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1

Synthesis and anti-microbial activities of choline-like quaternary ammonium chlorides.  

PubMed

New choline-like quaternary ammonium chlorides were obtained. The work-up procedure of synthesis was quick and efficient. The obtained chlorides showed anti-microbial activities. Quaternary ammonium chlorides derivatives of deanol esters exhibited strong activity and wide anti-bacterial spectra, similar to the activity of benzalkonium chloride. The relationship between chemical structure and anti-microbial activity was analyzed by the QSAR method. PMID:14642336

Pernak, Juliusz; Chwa?a, Przemys?aw

2003-01-01

2

40 CFR 721.10479 - Quaternary ammonium compounds, tris(hydrogenated tallow alkyl)methyl, chlorides.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Quaternary ammonium compounds, tris(hydrogenated tallow alkyl... § 721.10479 Quaternary ammonium compounds, tris(hydrogenated tallow alkyl...substance identified as quaternary ammonium compounds, tris(hydrogenated tallow...

2013-07-01

3

Surface-Bonded Antimicrobial Activity of an Organosilicon Quaternary Ammonium Chloride  

PubMed Central

The hydrolysis product of 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride exhibited antimicrobial activity against a broad range of microorganisms while chemically bonded to a variety of surfaces. The chemical was not removed from surfaces by repeated washing with water, and its antimicrobial activity could not be attributed to a slow release of the chemical, but rather to the surface-bonded chemical. Images

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

1972-01-01

4

Sorption of quaternary ammonium compounds to municipal sludge  

Microsoft Academic Search

The sorptive behavior of four quaternary ammonium compounds (QACs) – hexadecyl trimethyl ammonium chloride (C16TMA), dodecyl trimethyl ammonium chloride (C12TMA), hexadecyl benzyl dimethyl ammonium chloride (C16BDMA), and dodecyl benzyl dimethyl ammonium chloride (C12BDMA) – to municipal primary, waste activated, mesophilic digested, and thermophilic digested sludges was assessed at 22°C. Batch adsorption of all four separately tested QACs to primary sludge

Zainab Z. Ismail; Ulas Tezel; Spyros G. Pavlostathis

2010-01-01

5

Development, Characterization and Performance Evaluation of Positively-Charged Thin Film-Composite Nanofiltration Membrane Containing Fixed Quaternary Ammonium Moieties  

Microsoft Academic Search

Thin film composite (TFC) type positively-charged nanofiltration membranes, bearing fixed quaternary ammonium moieties, have been developed and studied. Branched polyethyleneimine (PEI) was functionalized by reaction with glycidyl trimethyl ammonium chloride (GTACl) to introduce quaternary ammonium chloride. Positively-charged TFC membranes were prepared by in situ interfacial polymerization of functionalized PEI and terephthaloyl chloride. The effects of variation of chemical compositions and

T. K. Dey; R. C. Bindal; S. Prabhakar; P. K. Tewari

2011-01-01

6

40 CFR 721.10582 - Quaternary ammonium compound (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Quaternary ammonium compound (generic). 721.10582 Section... § 721.10582 Quaternary ammonium compound (generic). (a) Chemical substance...identified generically as quaternary ammonium compound (PMN P-10-571) is subject...

2013-07-01

7

40 CFR 721.655 - Ethoxylated alkyl quaternary ammonium compound.  

Code of Federal Regulations, 2013 CFR

...Ethoxylated alkyl quaternary ammonium compound. 721.655 Section 721.655 ...Ethoxylated alkyl quaternary ammonium compound. (a) Chemical substance and significant...ethoxylated alkyl quaternary ammonium compound (PMN P-96-573) is subject...

2013-07-01

8

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

2013-12-14

9

Humidity sensor using epoxy resin containing quaternary ammonium salts  

Microsoft Academic Search

Humidity-sensitive epoxy monomer, glycidyl trimethyl ammonium chloride (GTMAC) was selected as the humidity-sensing resin. Polypropylene glycol diglycidyl ether (PPGDGE) and methyl tetrahydrophthalic anhydride (MTPHA) were used as a comonomer and a curing agent, respectively. The humidity-sensitive membranes were composed of GTMAC, PPGDGE and MTPHA. When impedance characteristics of the epoxy resins containing quaternary ammonium salts were measured, the impedance decreased

Chil-Won Lee; Hee-Woo Rhee; Myoung-Seon Gong

2001-01-01

10

Bacterial adhesion inhibition of the quaternary ammonium functionalized silica nanoparticles.  

PubMed

Quaternary ammonium compounds have been considered as excellent antibacterial agents due to their effective biocidal activity, long term durability and environmentally friendly performance. In this work, 3-(trimethoxysilyl)-propyldimethyloctadecylammonium chloride as a quaternary ammonium silane was applied for the surface modification of silica nanoparticles. The quaternary ammonium silane provided silica surface with hydrophobicity and antibacterial properties. In addition, the glass surface which was coated with the surface modified silica nanoparticles presented bacterial growth inhibition activity. For comparison of bacterial growth resistance, hydrophobic silane (alkyl functionalized silane) modified silica nanoparticles and pristine silica nanoparticles were prepared. As a result of bacterial adhesion test, the quaternary ammonium functionalized silica nanoparticles exhibited the enhanced inhibition performance against growth of Gram-negative Escherichia coli (96.6%), Gram-positive Staphylococcus aureus (98.5%) and Deinococcus geothermalis (99.6%) compared to pristine silica nanoparticles. These bacteria resistances also were stronger than that of hydrophobically modified silica nanoparticles. It could be explained that the improved bacteria inhibition performance originated from the synergistic effect of hydrophobicity and antibacterial property of quaternary ammonium silane. Additionally, the antimicrobial efficacy of the fabricated nanoparticles increased with decreasing size of the nanoparticles. PMID:21115282

Song, Jooyoung; Kong, Hyeyoung; Jang, Jyongsik

2011-02-01

11

Ototoxic effect of quaternary ammonium compounds.  

PubMed

In earlier investigations by the author it has been shown that chlorhexidine, when introduced into the middle ear of guinea pigs, caused serious damage to the inner ear. The present investigation was performed in order to study if the quaternary ammonium compounds benzethonium chloride and benzalkonium chloride, frequently used for skin disinfection, can also induce inner ear damage when introduced into the tympanic cavity of guinea pigs. The disinfectants in question, at a concentration of 0.1% and in a solution of aqua dest. or 70% alcohol, were introduced into the animals' middle ear for exposure times of 10, 30, or 60 min. The animals were sacrificed 2 or 9 weeks after the exposure and the organ of Corti and vestibular neuroepithelia were studied as surface preparations with phase contrast microscopy. It was found that most of the ears exposed to the disinfectants had suffered damage, affecting both the vestibular and cochlear parts of the inner ear. The extent of the damage was related both to the duration of exposure and to the length of the animals' survival after the exposure. Furthermore it was found that the tympanic cavity and the perilymphatic spaces of vestibulum and cochlea were pathologically changed. PMID:6125078

Aursnes, J

1982-01-01

12

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

Federal Register 2010, 2011, 2012, 2013

...chemical residue in or on a food) only if EPA determines that...ethylbenzyl ammonium chloride on food contact surfaces when applied...processing equipment, and/or food processing equipment and utensils...quaternary ammonium compounds in this cluster is chloride. However,...

2010-07-14

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

[Evaluating the effect of quaternary ammonium disinfectants on bacterial strains of animal origin].  

PubMed

The authors evaluate two quaternary ammonium compounds, first and second generation, using three methods: minimum bactericide concentration, the suspension test of the German Society for Hygiene and Microbiology and the agar gel diffusion test. The compounds were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis from sheep and pigs. The results show that quaternary ammonia compounds with dodecyl chains have greater efficacy than benzalconium chloride, and that quaternary ammonium compounds are more effective against gram-positive bacteria. No resistance linked to the strains used in the tests was detected. Finally, the authors demonstrate that all three techniques are valid for the evaluation of quaternary ammonium disinfectants. PMID:15005566

Rueda, J; Amigot Lázaro, J A; Ducha, J

2003-12-01

15

21 CFR 184.1138 - Ammonium chloride.  

Code of Federal Regulations, 2010 CFR

...12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution. The less soluble sodium salt separates out at elevated temperatures, and ammonium chloride is recovered from the filtrate on...

2009-04-01

16

21 CFR 184.1138 - Ammonium chloride.  

Code of Federal Regulations, 2010 CFR

...12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution. The less soluble sodium salt separates out at elevated temperatures, and ammonium chloride is recovered from the filtrate on...

2010-01-01

17

The Importance of Molecular Parameters of Quaternary Ammonium Salts in Their Antigibberellin (Retardant) Activity  

Microsoft Academic Search

The importance of six theoretically calculated molecular parameters in the antigibberellin (retardant) activity of quaternary ammonium salts is studied using a regression analysis. A bioassay system based on cell culture of fungus Gibberella fujikuroi is used to determine the activity. In the case of N,N,N-trimethyl-N-(2-hydroxyethyl)ammonium chloride (choline) and N,N,N-triethyl-N-(2-hydroxyethyl)ammonium chloride (N,N,N-triethylcholine) derivatives with linear structure, the polarizability, proton acceptor activity,

R. G. Gafurov; V. Yu. Grigor'ev; A. N. Proshin; V. G. Chistyakov; I. V. Martynov; N. S. Zefirov

2004-01-01

18

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

19

Sorption of quaternary ammonium compounds to municipal sludge.  

PubMed

The sorptive behavior of four quaternary ammonium compounds (QACs) - hexadecyl trimethyl ammonium chloride (C(16)TMA), dodecyl trimethyl ammonium chloride (C(12)TMA), hexadecyl benzyl dimethyl ammonium chloride (C(16)BDMA), and dodecyl benzyl dimethyl ammonium chloride (C(12)BDMA) - to municipal primary, waste activated, mesophilic digested, and thermophilic digested sludges was assessed at 22 degrees C. Batch adsorption of all four separately tested QACs to primary sludge reached equilibrium within 4h. At a nominal, initial QAC concentration of 300mg/L and a sludge volatile solids concentration of 1g/L, the extent of adsorption was 13, 88, 67, and 89% for the C(12)TMA, C(16)TMA, C(12)BDMA, and C(16)BDMA, respectively, and correlated positively to the QAC hydrophobicity and negatively to their critical micelle concentration. Equilibrium partitioning data were described by the Freundlich isotherm model. The adsorption capacity of the four sludges was very similar. In binary QAC mixtures, QACs with relatively high adsorption affinity and at relatively high aqueous concentrations decreased the adsorption of QACs with a low adsorption affinity. At pH 7, about 40% of the sludge-C(12)TMA desorbed, whereas less than 5% of the sludge-C(16)BDMA desorbed in 10 days. The effect of pH was negligible on the desorption extent of C(12)TMA at a pH range 4-10 over 10 days, whereas increasing the solution pH to 10 resulted in more than 50% desorption of C(16)BDMA. Given the fact that approximately 50% of the municipal biosolids are land-applied in the US, the data of this study would help in the assessment of the fate of QACs and their potential effect on human and environmental health. PMID:20045549

Ismail, Zainab Z; Tezel, Ulas; Pavlostathis, Spyros G

2010-04-01

20

40 CFR 721.10666 - Quaternary ammonium compounds, bis(fattyalkyl) dimethyl, salts with tannins (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Quaternary ammonium compounds, bis(fattyalkyl) dimethyl, salts... § 721.10666 Quaternary ammonium compounds, bis(fattyalkyl) dimethyl, salts...identified generically as quaternary ammonium compounds, bis(fattyalkyl) dimethyl,...

2013-07-01

21

40 CFR 721.10342 - Quaternary ammonium compounds, fatty alkyl dialkyl hydroxide (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Quaternary ammonium compounds, fatty alkyl dialkyl hydroxide (generic... § 721.10342 Quaternary ammonium compounds, fatty alkyl dialkyl hydroxide (generic...identified generically as quaternary ammonium compounds, fatty alkyl dialkyl...

2013-07-01

22

40 CFR 721.9075 - Quaternary ammonium salt of fluorinated alkylaryl amide.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Quaternary ammonium salt of fluorinated alkylaryl amide. 721...Substances § 721.9075 Quaternary ammonium salt of fluorinated alkylaryl amide. ...identified generically as quaternary ammonium salt of fluorinated alkylaryl amide...

2011-07-01

23

40 CFR 721.9075 - Quaternary ammonium salt of fluorinated alkylaryl amide.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Quaternary ammonium salt of fluorinated alkylaryl amide. 721...Substances § 721.9075 Quaternary ammonium salt of fluorinated alkylaryl amide. ...identified generically as quaternary ammonium salt of fluorinated alkylaryl amide...

2010-07-01

24

Tri-benzyl-ammonium chloride.  

PubMed

Single crystals of the title salt, C21H21NH(+)·Cl(-), were isolated as a side product from the reaction involving [(C6H5CH2)3NH]2[HPO4] and Sn(CH3)3Cl in ethanol. Both the cation and the anion are situated on a threefold rotation axis. The central N atom in the cation has a slightly distorted tetra-hedral environment, with angles ranging from 107.7 to 111.16?(10)°. In the crystal, the tri-benzyl-ammonium cations and chloride anions are linked through N-H?Cl and C-H?Cl hydrogen bonds, leading to the formation of infinite chains along [001]. The crystal studied was a merohedral twin. PMID:24860409

Diallo, Waly; Diop, Libasse; Plasseraud, Laurent; Cattey, Hélène

2014-05-01

25

Tri-benzyl-ammonium chloride  

PubMed Central

Single crystals of the title salt, C21H21NH+·Cl?, were isolated as a side product from the reaction involving [(C6H5CH2)3NH]2[HPO4] and Sn(CH3)3Cl in ethanol. Both the cation and the anion are situated on a threefold rotation axis. The central N atom in the cation has a slightly distorted tetra­hedral environment, with angles ranging from 107.7 to 111.16?(10)°. In the crystal, the tri­benzyl­ammonium cations and chloride anions are linked through N—H?Cl and C—H?Cl hydrogen bonds, leading to the formation of infinite chains along [001]. The crystal studied was a merohedral twin.

Diallo, Waly; Diop, Libasse; Plasseraud, Laurent; Cattey, Helene

2014-01-01

26

Low Sensitivity of Listeria monocytogenes to Quaternary Ammonium Compounds  

PubMed Central

Ninety-seven epidemiologically unrelated strains of Listeria monocytogenes were investigated for their sensitivities 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 pump, and the orfA gene, a putative transcriptional repressor of mdrL. The absence of plasmids in four of the seven resistant strains and the conservation of resistance after plasmid curing suggested that the resistance genes are not plasmid borne. Moreover, PCR amplification and Southern blot hybridization experiments failed to find genes phylogenetically related to the qacA and smr genes, encoding multidrug efflux systems previously described for the genus Staphylococcus. The high association between nontypeability by phages and the loss of sensitivity to quaternary ammonium compounds are suggestive of an intrinsic resistance due to modifications in the cell wall.

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

2000-01-01

27

Crystalline molecular sieve synthesis using quaternary ammonium-functionalized organosiliconate  

US Patent & Trademark Office Database

This invention relates to a method for preparing crystalline silicates such as zeolites from a forming mixture containing quaternary ammonium-functionalized organosiliconate as a directing agent. The products prepared depend, inter alia, on reaction conditions such as temperature, crystallization time, and pH. More particularly, this invention relates to the use of a quaternary ammonium-functionalized organosiliconate in the preparation of ZSM-5, ZSM-48, ZSM-51 and the ZSM-48 composition thus prepared.

1993-03-16

28

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

2013-04-01

29

21 CFR 184.1138 - Ammonium chloride.  

Code of Federal Regulations, 2013 CFR

...NH4 Cl, CAS Reg. No. 12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution...strengthener as defined in § 170.3(o)(6) of this chapter; a flavor enhancer as defined in § 170.3(o)(11) of this...

2013-04-01

30

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

SciTech Connect

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 used. Some inorganic anions thus titratable are perrhenate, persulfate, ferricyanide, hexafluorophosphate, and hexachloroplatinate. Examples of organic anions titratable are nitroform, tetraphenylborate, cyanotriphenylborate, picrate, long-chain sulfates and sulfonates, and some soaps. The reverse titration of quaternary ammonium halides vs dodecylsulfate is also feasible. Some titrations are feasible in a partially nonaqueous medium.

Selig, W.

1980-01-01

31

New quaternary benzyl chloride salts for inclusion in hair cream rinse formulations  

Microsoft Academic Search

Quaternary ammonium salts have been prepared from benzyl chloride and amino amides and an amino ester of a long chain fatty\\u000a acid. These benzyl salts were incorporated in simple hair conditioner formulations containing the quaternary salt, anhydrous\\u000a lanolin, cetyl alcohol, and water. Preliminary evaluations indicated that the formulations were effective in the removal of\\u000a tangles and snarls following washing with

A. V. Bailey; G. Sumrell; T. E. Gurtner

1974-01-01

32

[The biological activity of quaternary ammonium salts (QASs)].  

PubMed

Quaternary ammonium salts (QASs), especially those of cationic surfactant character, are applied as antibacterial and antifungal disinfectants. QASs affect lipid-enveloped viruses, including human immunodeficiency virus (HIV) and hepatitis B virus (HBV), but not non-enveloped viruses. These compounds are extensively used in domestic (as ingredients of shampoos, hair conditioners), agricultural (as fungicides, pesticides, insecticides), healthcare (as medications), and industrial applications (as biocides, fabric softeners, corrosion inhibitors). The extensive use of quaternary ammonium disinfectants in recent years has led to the development of resistance in microorganisms to these drugs. Thus Staphylococcus aureus strains contain the plasmid-carrying genes qacA and qacB encoding resistance to quaternary ammonium compounds and acriflavine. The membrane proteins QacA and QacB confer multidrug resistance by exporting the compound by the proton motive force which is generated by the transmembrane electrochemical proton gradient. PMID:20400784

Ob?ak, Ewa; Gamian, Andrzej

2010-01-01

33

Quaternary ammonium functionalized poly(propylene imine) dendrimers as effective antimicrobials: structure-activity studies.  

PubMed

Quaternary ammonium functionalized poly(propyleneimine) dendrimers were synthesized and their antibacterial properties were evaluated using a bioluminescence method. These quaternary ammonium dendrimers are very potent biocides. The antibacterial properties depend on the size of the dendrimer, the length of hydrophobic chains in the quaternary ammonium groups, and the counteranion. Since these dendrimers are well characterized and monodisperse, they also serve as an effective system to study the structure-activity relationship. The antimicrobial properties of these dendrimer biocides have a parabolic dependence on molecular weight, which is different from the bell-shaped molecular weight dependence of conventional polymer biocides. The dependence on the hydrophobic chain of the quaternary ammonium structure is similar to conventional polymer biocides, and shows a parabolic relationship with dendrimer biocides carrying C10 hydrophobes the most potent. The antimicrobial properties of these novel biocides with bromide anions are more potent than those with chloride anions. Biocides derived from hyperbranched polymers were also synthesized and found to possess somewhat lower effectiveness. PMID:11710139

Chen, C Z; Beck-Tan, N C; Dhurjati, P; van Dyk, T K; LaRossa, R A; Cooper, S L

2000-01-01

34

Fractionation of Serum Proteins with a Quaternary Ammonium Detergent  

Microsoft Academic Search

THE fractionation of serum proteins with the aid of quaternary ammonium compounds has met with difficulties, because the detergent\\/protein ratio must be maintained at a very constant level1. We have shown that this is no longer necessary if `Desogen' (methylphenyl dodecyltrimethyl-ammonium-methosulphate, Geigy S.A., Basle) is used. Separation into at least four components can be performed by the following method.

F. J. Loomeijer

1950-01-01

35

Double-Chain Surfactants with Two Quaternary Ammonium Head Groups.  

National Technical Information Service (NTIS)

Double-chain surfactants with two quaternary ammonium head groups were prepared: 2-(7-trimethylammo nioheptyl)-2-decyl-4-(8-trimethyla mmoniooctyl)-5-octyl-1- 3-dioxolane dibromide (3) and 2-(3- trimethylammoniopropyl) -2-tetradecyl-4-(8-trimethylammo nio...

D. A. Jaeger S. G. Russell H. Shinozaki

1994-01-01

36

Biologically active polymers: synthesis and antimicrobial activity of modified glycidyl methacrylate polymers having a quaternary ammonium and phosphonium groups  

Microsoft Academic Search

Polymers with antibacterial activity have been synthesized by chemical modification of poly(glycidyl methacrylate). The glycidyl methacrylate was polymerized by the free radical polymerization technique. The poly(glycidyl methacrylate) was hydrolyzed and was chloroacetylated using chloroacetyl chloride. The chloroacetylated product was modified to yield polymers with either quaternary ammonium or phosphonium salts. The antimicrobial activity of the modified glycidyl methacrylate polymers has

El-Refaie Kenawy; Fouad I Abdel-Hay; Abd El-Raheem R El-Shanshoury; Mohamed H El-Newehy

1998-01-01

37

Antimicrobial cotton containing N-halamine and quaternary ammonium groups by grafting copolymerization  

NASA Astrophysics Data System (ADS)

The monomer (3-acrylamidopropyl)trimethylammonium chloride (APTMAC) was used to treat cotton fibers by grafting copolymerization. The grafted cotton fabrics were characterized by SEM image and FTIR spectra. The treated samples with quaternary ammonium groups could decrease 96.08% of Staphylococcus aureus and 48.74% of Escherichia coli O157:H7 within 30 min. After chlorination with dilute sodium hypochlorite, the treated cotton fabrics containing both N-halamine and quaternary ammonium groups effectively inactivated 100% (log reduction 5.82) of S. aureus and 100% (log reduction 6.26) of E. coli O157:H7 within 5 min of contact time. The grafting process of cotton fabric has small effect on the thermal stability and tensile strength, which favors the practical application. Compared to the traditional pad-dry-cure method to produce antibacterial materials, the radical grafting copolymerization method occurred in water without any organic solvents involved in the whole treatment.

Liu, Ying; Liu, Yin; Ren, Xuehong; Huang, T. S.

2014-03-01

38

?-CD assisted dissolution of quaternary ammonium permanganates in aqueous medium.  

PubMed

The non-polar internal cavity of ?-cyclodextrin (?-CD) has been exploited for the entrapment of the hydrophobic tails of two water insoluble quaternary ammonium permanganates (QAPs): cetyltrimethylammonium permanganate (CTAP) and tetrabutylammonium permanganate (TBAP), for solubilization in aqueous medium. The solubilization and organizational behavior of the QAPs in aqueous ?-CD solution have been determined from the comparison of their rates of self-oxidation in presence and in absence of ?-CD. Effect of QAP concentration on their observed rate constants (kobs) at a fixed ?-CD concentration, phase solubility analysis in varying ?-CD concentration, impact of quaternary ammonium bromides (QABs) on the kobs values of CTAP and TBAP at fixed QAP and ?-CD concentrations, and the temperature effect have been reported. A scheme to explain the solvation of QAPs in aqueous ?-CD has been proposed based on dynamic light scattering (DLS) analysis of the samples. PMID:25037419

Bank, Suraj Prakash; Guru, Partha Sarathi; Dash, Sukalyan

2014-10-13

39

Sorption of Polymeric Quaternary Ammonium Compounds to Humic Acid  

Microsoft Academic Search

Polymeric quaternary ammonium salts or polyquaterniums are used not only in the water and wastewater industry but also in\\u000a cosmetics. The former have been extensively studied with sorption to wastewater treatment plant (WWTP) biosolids an important\\u000a factor in their fate, mitigating release to the environment. Compounds of cosmetic origin have not received the same scrutiny\\u000a as those used in other

Janet Cumming; Darryl William Hawker; Heather Chapman; Kerry Nugent

2011-01-01

40

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 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...

2010-07-01

41

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

42

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

Code of Federal Regulations, 2013 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...

2013-07-01

43

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

44

Antibacterial effects of three experimental quaternary ammonium salt (QAS) monomers on bacteria associated with oral infections.  

PubMed

The aim of this study was to test the antibacterial effects of three experimental quaternary ammonium salt monomers in order to evaluate their potential applications as dental materials. In vitro susceptibility testing of the monomers was performed by the broth dilution method on bacteria associated with oral infections: Streptococcus mutans ATCC 25175, Actinomyces viscosus ATCC 15987, Staphylococcus aureus ATCC 29213 and Lactobacillus casei ATCC 393. The time-kill kinetics of the monomer with relatively higher antibacterial activity against S. mutans were also investigated. It was found that all the tested bacteria strains were susceptible to the three monomers, among which methacryloxylethyl cetyl ammonium chloride (DMAE-CB) exhibited the lowest minimal inhibitory concentrations, ranging from 1.2 to 4.8 microg/ml. The time-kill curve showed that DMAE-CB achieved 99.44% killing at 19.2 microg/ml (4 times the minimal bactericidal concentration) against S. mutans after 1 min and 100% killing within 10 min of contact. This result indicates that the quaternary ammonium salt monomer DMAE-CB may be a candidate antibacterial agent for incorporation into dental restorative materials. PMID:18818469

Xiao, Yu-Hong; Chen, Ji-Hua; Fang, Ming; Xing, Xiao-Dong; Wang, Hui; Wang, Ying-Jie; Li, Fang

2008-09-01

45

Dispersion copolymerization of acrylamide with quaternary ammonium cationic monomer in aqueous salts solution  

Microsoft Academic Search

Dispersion copolymerization of acrylamide (AM) with 2-methylacryloylxyethyl trimethyl ammonium chloride (DMC) has been carried out in aqueous salts solution containing ammonium sulfate and sodium chloride with poly(acryloylxyethyl trimethyl ammonium chloride) (PDAC) as the stabilizer and 2,2?-azobis[2-(2-inidazolin-2-yl)propane]-dihydro chloride (VA-044) as the initiator. A new particle formation mechanism of the dispersion polymerization for the present system has been proposed. The effects of

Dongnian Chen; Xiaoguang Liu; Yumei Yue; Wende Zhang; Pixin Wang

2006-01-01

46

Flocculation of Escherichia coli Using a Quaternary Ammonium Salt Grafted Carboxymethyl Chitosan Flocculant.  

PubMed

Only few studies are available on bacteria removal efficiencies and antibacterial properties of flocculants, which is one of the important requirements in water treatment work. Escherichia coli (E. coli) was selected as an example of a Gram-negative bacteria for testing the flocculating properties of a quaternary ammonium salt grafted chitosan (carboxymethyl chitosan-graft-poly[(2-methacryloyloxyethyl) trimethylammonium chloride] copolymer; i.e., CMC-g-PDMC). The effect of various flocculation parameters, including flocculant dosage, initial bacterial density, nutrient medium content, and pH were successively investigated. The experimental results indicated that, besides flocculation effects, CMC-g-PDMC also exhibited a bactericidal effect (not requiring additional treatment facilities). Moreover, the flocculation mechanisms were investigated via zeta potential measurements, floc observation, and three-dimensional excitation-emission matrix spectra analysis. Apart from its flocculating and settling effect, this chitosan-based material has bactericidal action through the breaking of bacterial cell walls by grafted quaternary ammonium salt. PMID:24871697

Yang, Zhen; Degorce-Dumas, Jean-Regis; Yang, Hu; Guibal, Eric; Li, Aimin; Cheng, Rongshi

2014-06-17

47

Sorption of quaternary ammonium compounds in soils: Implications to the soil microbial activities  

Microsoft Academic Search

Despite their widespread use in household activities and various industries, information on the toxicity of quaternary ammonium compounds (QACs) to microbial activities in soil is scant. This study investigated the effect of three commonly used QACs namely hexadecyltrimethyl ammonium bromide (HDTMA), octadecyltrimethyl ammonium bromide (ODTMA) and Arquad on dehydrogenase and potential nitrification activities in three different soils. The toxicity of

Binoy Sarkar; Mallavarapu Megharaj; Yunfei Xi; G. S. R. Krishnamurti; Ravi Naidu

2010-01-01

48

Quaternary ammonium derivatives as spasmolytics for irritable bowel syndrome.  

PubMed

Quaternary ammonium derivatives such as cimetropium, n-butyl scopolammonium, otilonium and pinaverium bromide have been discovered and developed as potent spasmolytics of the gastrointestinal tract. Their pharmacological activity has been proven in both "in vivo" and "in vitro" studies of hypermotility. "In vitro" experiments showed that they possess antimuscarinic activity at nM level but only pinaverium and otilonium are endowed with calcium channel blocker properties. These latter compounds relaxed the gastrointestinal smooth muscle mainly through a specific inhibition of calcium ion influx through L-type voltage operated calcium channels. Molecular pharmacology trials have indicated that pinaverium and otilonium can bind specific subunits of the calcium channel in the external surface of the plasma membrane and in this way they block the machinery of the contraction. Recent evidence showed that otilonium is able to bind tachykinin NK(2) receptors and not only inhibits one of the major contractile agents but can reduce the activation of afferent nerves devoted to the passage of sensory signals from the periphery to the central nervous system. Thanks to their typical physico-chemical characteristics, they are poorly absorbed by the systemic circulation and generally remain in the gastrointestinal tract where they exert the muscle relaxant activity by a local activity. Some differences exists in the absorption among these compounds: both n-butyl scopolammonium and cimetropium are partially taken up in the bloodstream, pinaverium has a low absorption (8-10 %) but is endowed with an excellent hepato-biliary excretion and otilonium, which has the lowest absorption (3 %), is almost totally excreted by faeces. Quaternary ammonium derivatives are widely used for the treatment of irritable bowel syndrome and recent meta-analyses have supported their efficacy in this disease. Due to its therapeutic index, the use of n-butyl scopolammonium is more indicated to treat acute colics than a chronic disease such as irritable bowel syndrome. Taking into consideration the published trials carried out with validated methodology in irritable bowel syndrome, cimetropium and otilonium are the best demonstrated drugs for the improvement in global assessment, pain and abdominal distension. PMID:15579053

Evangelista, S

2004-01-01

49

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

50

Antibacterial properties of poly(quaternary ammonium) modified gold and titanium dioxide nanoparticles.  

PubMed

We report excellent antibacterial effect induced by amine-functionalized gold and titanium dioxide nanoparticles without external excitations. The idea originates from the excellent antibacterial property of quaternary ammonium salts. The effects of poly(quaternary ammonium) and polyacrylate sodium functional groups as nanoparticle surfactants are compared to show that poly(quaternary ammonium) functional groups are the main cause of the induced antibacterial effect. 99.999% of E. coli can be destructed in 10 minutes by simply mixing bacteria with nanoparticle dispersions. The effect of nanoparticle concentrations on the antibacterial property is evaluated. Time required to significantly suppress bacteria growth is studied. The result indicates that the excellent antibacterial property can be introduced to any nanomaterials by using poly(quaternary ammonium) functional groups as surfactants. The engineered nanoparticles can find enormous applications such as self-cleaning surfaces, waste water treatment, Lab-on-a-Chip devices and many more. PMID:22905506

Wan, Weijie; Yeow, John T W

2012-06-01

51

Biological evaluation of quaternary bis ammonium salt and cetylpyridinum bromide against S. epidermidis biofilm.  

PubMed

Quaternary ammonium compounds are broad-spectrum bacteriocides widely used as antiseptics, disinfection and preservation agents. The aim of this study was to examine the activity of two quaternary ammonium salts, cetylpyridinum bromide and a newly synthesized quaternary bis ammonium salt, against S. epidermidis biofilm. The average values of killing efficiency for cetylpyridinum bromide ranged from 26.6% to 64.1% for all tested concentrations (0.125 to 8.0 microg x mL(-1)) and for quaternary bis ammonium salt the percentage of killing efficiency ranged from 59.7% to 88.4% for tested concentrations (from 2.0 to 128.0 microg x mL(-1)). Both tested compounds significantly affect staphylococcal biofilms, but any of used concentrations caused a total eradication of bacterial biofilm. PMID:24730129

Stefa?ska, Joanna; Pietruczuk-Padzik, Anna; Struga, Marta; Borkowski, Maciej; Tyski, Stefan

2013-01-01

52

Kinetics of tethering quaternary ammonium compounds to K(+) channels.  

PubMed

Polymeric maleimido-quaternary ammonium (QA) compounds have been shown to function as molecular tape measures when covalently tethered to external cysteine residues of a Shaker K(+) channel (Blaustein R.O., P.A. Cole, C. Williams, and C. Miller. 2000. Nat. Struct. Biol. 7:309-311). For sufficiently long compounds, the cysteine-maleimide tethering reaction creates a high concentration, at the channel's pore, of a TEA-like moiety that irreversibly blocks current. This paper investigates a striking feature of the maleimide-cysteine tethering kinetics. Strong blockers-those that induce substantial levels (>80%) of irreversible inhibition of current-react with channel cysteines much more rapidly than weak blockers and, when delivered to channels with four cysteine targets, react with multiexponential kinetics. This behavior is shown to arise from the ability of a strong blocker to concentrate its maleimide end near a channel's cysteine target by exploiting the reversible pore-blocking affinity of its QA headgroup. PMID:12149281

Blaustein, Robert O

2002-08-01

53

Antibacterial Nanocomposite with Calcium Phosphate and Quaternary Ammonium  

PubMed Central

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-PO4 release capability, may render it useful for caries-inhibiting restorations.

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

2012-01-01

54

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

2011-12-01

55

Effects of quaternary ammonium chain length on antibacterial bonding agents.  

PubMed

The objectives of this study were to synthesize new quaternary ammonium methacrylates (QAMs) with systematically varied alkyl chain lengths (CL) and to investigate, for the first time, the CL effects on antibacterial efficacy, cytotoxicity, and dentin bond strength of bonding agents. QAMs were synthesized with CL of 3 to 18 and incorporated into Scotchbond Multi-Purpose (SBMP) bonding agent. The cured resins were inoculated with Streptococcus mutans. Bacterial early attachment was investigated at 4 hrs. Biofilm colony-forming units (CFU) were measured after 2 days. With CL increasing from 3 to 16, the minimum inhibitory concentration and minimum bactericidal concentration were decreased by 5 orders of magnitude. Incorporating QAMs into SBMP reduced bacterial early attachment, with the least colonization at CL = 16. Biofilm CFU for CL = 16 was 4 log lower than SBMP control (p < .05). All groups had similar dentin bond strengths (p > .1). The new antibacterial materials had fibroblast/odontoblast viability similar to that of commercial controls. In conclusion, increasing the chain length of new QAMs in bonding agents greatly increased the antibacterial efficacy. A reduction in Streptococcus mutans biofilm CFU by 4 log could be achieved, without compromising bond strength and cytotoxicity. New QAM-containing bonding agents are promising for a wide range of restorations to inhibit biofilms. PMID:23958761

Li, F; Weir, M D; Xu, H H K

2013-10-01

56

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

2012-05-01

57

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

58

Modelling growth responses of soil nitrifiers to additions of ammonium sulphate and ammonium chloride  

Microsoft Academic Search

Summary Following the addition of 0–75 ?mole N g?1 as ammonium chloride or ammonium sulphate to a sandy loam soil the nitrate formed was measured daily for a period of 15–17 days. The nitrate produced as a function of time was described using the Monod equation for microbial growth. An optimisation technique is described for obtaining, from the nitrification time

P. R. Darrah; P. H. Nye; R. E. White

1985-01-01

59

Synthesis and characterization of poly(vinyl alcohol) membranes with quaternary ammonium groups for wound dressing.  

PubMed

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 properties, water take, water vapor transmission rate (WVTR), contact angle, antibacterial activity and cytotoxicity of PVA-g-PAETMAC membranes were investigated. The experiment results showed that PVA-g-PAETMAC membrane has a higher equilibrium swelling ratio, surface hydrophilicity and WVTR than pure PVA membrane. Moreover, the higher the content of AETMAC, the higher were equilibrium swelling ratio, surface hydrophilicity and WVTR. In vitro bacterial adhesion study demonstrated a significantly reduced number of Staphylococcus aureus and Escherichia coli on PVA-g-PAETMAC surfaces when compared to PVA surface. In addition, no significant difference in the in vitro cytotoxicity was observed between PVA and PVA-g-PAETMAC membranes. The presence of quaternary ammonium groups did not reduce L929 cell growth. Therefore, the PVA-g-PAETMAC membranes have the potential for wound-dressing application. PMID:20233501

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

2010-01-01

60

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

61

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

62

Synthesis and structure-activity study of quaternary ammonium functionalized beta-cyclodextrin-carboxymethylcellulose polymers.  

PubMed

Carboxymethylcellulose (CMC) and beta-cyclodextrin (beta-CD)-based polymers functionalized with two types of quaternary ammonium compounds (QACs), the alkaquat DMB-451 (N-alkyl (50% C14, 40% C12, 10% C10) dimethylbenzylammonium chloride) (DMD-451) named polymer DMB-451, and FMB 1210-8 (a blend of 32 w% N-alkyl (50% C14, 40% C12, 10% C10) dimethylbenzylammonium chloride and 48 w% of didecyldimethylammonium chloride) named polymer FMB 1210-8, were synthethized and characterized by Fourier transform infrared spectroscopy. The antimicrobial activities of these polymers against Eschericia coli were also evaluated at 25 degrees C in wastewater. The results have indicated that the polymer FMB 1210-8 possesses a high-affinity binding with bacterial cells that induces a rapid disinfection process. Moreover, in the same experimental conditions of disinfection (mixture of 1.0 g of polymer and 100 mL of wastewater), the polymer FMB 1210-8 has a higher antimicrobial efficiency (99.90%) than polymer DMB-451 (92.8%). This phenomenon might be associated to a stronger interaction with bacterial cells due to stronger binding affinity for E. coli cells and greater killing efficiency of the C10 alkyl chains QAC of polymer FMB 1210-8 to disrupt the bacterial cell membrane as compared to N-alkyl (50% C14, 40% C12, 10% C10) dimethylbenzylammonium chloride. Together, these results suggest that the polymer FMB 1210-8 could constitute a good disinfectant against Escherichia coli, which could be advantageously used in wastewater treatments due to the low toxicity of beta-CD and CMC, and moderated toxicity of FMB 1210-8 to human and environment. PMID:22049706

Bonenfant, Danielle; Bourgeois, François-René; Mimeault, Murielle; Monette, Frédéric; Niquette, Patrick; Hausler, Robert

2011-01-01

63

Thermodynamics of Aqueous Solutions of Quaternary Ammonium Salts.  

National Technical Information Service (NTIS)

Activity and osmotic coefficients were determined by the isopiestic method, and density measurements were made in order to determine partial molal volumes. The solute salts were n-tetra-butyl ammonium bromide and fluoride, tetra methyl ammonium fluoride, ...

W. Y. Wen

1965-01-01

64

Mercury intoxication from skin ointment containing mercuric ammonium chloride  

Microsoft Academic Search

Objective. A one-year follow-up was performed of a 21-year-old man with a 16-year history of diabetes mellitus type I, who had been using ointment containing 10% mercuric ammonium chloride (hydrargyrum amidochloratum; HgNH2Cl) for eczema for approximately 3 weeks. Tiredness, fasciculations on the extremities and poor control of diabetes appeared after the end of the ointment treatment. Nephrotic syndrome and hypertension

D. Pelclová; E. Lukáš; P. Urban; J. Preiss; R. Ryšavá; P. Lebenhart; B. Okrouhlík; Z. Fenclová; J. Lebedová; A. Stejskalová; P. Ridzo?

2002-01-01

65

Alkyl dimethyl benzyl ammonium chloride adsorption mechanism on wood  

Microsoft Academic Search

The adsorption of alkyl dimethyl benzyl ammonium chloride (ADBAC) on wood was investigated. The changes in zeta potential\\u000a curves of wood and ADBAC adsorption with increasing ADBAC concentration were highly correlated and showed two different mechanisms\\u000a for ADBAC adsorption on wood: ion exchange reaction at low concentration and additional aggregation form of adsorption by\\u000a hydrophobic interaction at high concentration. ADBAC

Myung Jae Lee; Paul Cooper

2010-01-01

66

Combined hydrous ferric oxide and quaternary ammonium surfactant tailoring of granular activated carbon for concurrent arsenate and perchlorate removal  

Microsoft Academic Search

Activated carbon was tailored with both iron and quaternary ammonium surfactants so as to concurrently remove both arsenate and perchlorate from groundwater. The iron (hydr)oxide preferentially removed the arsenate oxyanion but not perchlorate; while the quaternary ammonium preferentially removed the perchlorate oxyanion, but not the arsenate. The co-sorption of two anionic oxyanions via distinct mechanisms has yielded intriguing phenomena. Rapid

Min Jang; Fred S. Cannon; Robert B. Parette; Soh-joung Yoon; Weifang Chen

2009-01-01

67

Effects of Quaternary Ammonium Silane Coatings on Mixed Fungal and Bacterial Biofilms on Tracheoesophageal Shunt Prostheses  

PubMed Central

Two quaternary ammonium silanes (QAS) were used to coat silicone rubber tracheoesophageal shunt prostheses, yielding a positively charged surface. One QAS coating [(trimethoxysilyl)-propyldimethyloctadecylammonium chloride] was applied through chemical bonding, while the other coating, Biocidal ZF, was sprayed onto the silicone rubber surface. The sprayed coating lost its stability within an hour, while the chemically bonded coating appeared stable. Upon incubation in an artificial throat model, allowing simultaneous adhesion and growth of yeast and bacteria, all coated prostheses showed significant reductions in the numbers of viable yeast (to 12% to 16%) and bacteria (to 27% to 36%) compared with those for silicone rubber controls, as confirmed using confocal laser scanning microscopy after live/dead staining of the biofilms. In situ hybridization with fluorescently labeled oligonucleotide probes showed that yeasts expressed hyphae on the untreated and Biocidal ZF-coated prostheses but not on the QAS-coated prostheses. Whether this is a result of the positive QAS coating or is due to the reduced number of bacteria is currently unknown. In summary, this is the first report on the inhibitory effects of positively charged coatings on the viability of yeasts and bacteria in mixed biofilms. Although the study initially aimed at reducing voice prosthetic biofilms, its relevance extends to all biomedical and environmental surfaces where mixed biofilms develop and present a problem.

Oosterhof, Janine J. H.; Buijssen, Kevin J. D. A.; Busscher, Henk J.; van der Laan, Bernard F. A. M.; van der Mei, Henny C.

2006-01-01

68

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

69

Dual action antimicrobials: nitric oxide release from quaternary ammonium-functionalized silica nanoparticles.  

PubMed

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-diazeniumdiolate NO donors to yield dual functional nanomaterials with surface QAs and total NO payloads of 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 Gram-positive 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. PMID:22998760

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

2012-10-01

70

Synthesis and biological activity of quaternary ammonium salt-type agents containing cholesterol and terpenes.  

PubMed

New quaternary ammonium salt-type compounds with lipophilic cholesterol and terpene moieties were synthesized. The compounds showed promising antibacterial and antimycobacterial activities. Those compounds containing the cholesterol moiety showed significant activity against Staphylococcus aureus, Staphylococcus epidermidis, and Enterococcus faecium. On the contrary, the antimycobacterial activity increased with the presence of the terpene unit in the molecule. PMID:24664885

Novotná, Eva; Waisser, Karel; Kuneš, Ji?í; Palát, Karel; Buchta, Vladimír; Stola?íková, Ji?ina; Beckert, Rainer; Wsól, Vladimír

2014-06-01

71

Effect of ten quaternary ammonium cations on tetrachloromethane sorption to clay from water  

Microsoft Academic Search

The mineral surface of Wyoming bentonite (clay) was modified by replacing inorganic ions by each of 10 quaternary ammonium compounds, and tetrachloromethane sorption to the modified sorbents from water was studied. Tetrachloromethane sorption from solution to clay modified with tetramethyl-, tetraethyl-, benzyltrimethyl-, or benzyltriethylammonium cations generally is characterized by relatively high solute uptake, isotherm nonlinearity, and competitive sorption (with trichloroethene

James A. Smith; Peter R. Jaffe; Cary T. Chiou

1990-01-01

72

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

Microsoft Academic Search

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

A. F. Nikiforov; O. V. Astafeva; T. V. Lobukhina

1987-01-01

73

Thermal analysis of montmorillonites modified with quaternary phosphonium and ammonium surfactants  

Microsoft Academic Search

The thermal stability of seven organically modified montmorillonites (‘organoclays’) has been investigated using differential thermal analysis, differential scanning calorimetry, and thermogravimetry in conjunction with X-ray diffractometry. Six organoclays were synthesised by replacing the interlayer inorganic cations, initially present, with quaternary phosphonium and ammonium surfactant cations. The samples modified with tetrabutylphosphonium (TBP), and butyltriphenylphosphonium (BTPP) ions have an appreciably higher thermal

C. B. Hedley; G. Yuan; B. K. G. Theng

2007-01-01

74

An innovative quaternary ammonium methacrylate polymer can provide improved antimicrobial properties for a dental adhesive system.  

PubMed

A quaternary ammonium methacrylate polymer (QAMP) with antimicrobial potential was synthesized. The resulting product (QAMP) was characterized by FTIR spectroscopy, NMR spectroscopy, visible spectrophotometry, XRPD and TGA. The in vitro susceptibility tests against Streptococcus mutans of QAMP were investigated prior and after incorporation into a commercial adhesive system (Clearfil™ SE Bond). The release of quaternary ammonium compounds from the experimental adhesive system (Clearfil™ SE Bond + 5% QAMP) was performed during 1, 7, 14, 21 and 30 days. Spectroscopic data confirmed that QAMP was successfully obtained. Thermogravimetric analysis indicated that QAMP was heat stable. Prior incorporation into the adhesive system, QAMP revealed an inhibition halo of 18.33 ± 0.6 mm. By agar disk diffusion test, Clearfil™ SE Bond containing 5% QAMP presented an inhibition halo (16.67 ± 1.5 mm) similar to Clearfil™ Protect Bond (positive control, 17.00 ± 1.7, p = 0.815) and significantly higher than Clearfil™ SE Bond (negative control, 11.00 ± 1.0, p = 0.006). The minimum inhibitory/bactericidal concentrations for Clearfil™ SE Bond containing 5% QAMP were 20 ?L mL(-1). The release of quaternary ammonium compounds from the experimental adhesive containing QAMP was very low (5.1%) when compared to Clearfil™ Protect Bond that released 47.2% of its quaternary ammonium monomer (MDPB) after 30 days. The QAMP can offer enhanced antimicrobial properties for self-etching adhesive systems. PMID:23829457

Pupo, Yasmine Mendes; Farago, Paulo Vitor; Nadal, Jessica Mendes; Esmerino, Luis Antônio; Maluf, Daniela Florencio; Zawadzki, Sônia Faria; Michél, Milton Domingos; dos Santos, Fábio André; Gomes, Osnara Maria Mongruel; Gomes, João Carlos

2013-01-01

75

ELECTROSPINNING OF LOW SURFACE ENERGY QUATERNARY AMMONIUM SALT CONTAINING POLYMERS AND THEIR ANTIBACTERIAL ACTIVITY  

Microsoft Academic Search

Antibacterial agent (quaternary ammonium salt) containing perfluorinated polymers had been synthesized at different agent concentrations. The polymers were dissolved in solvent mixture and electrospun, to increase effective surface area, at 12 kV which had resulted nanofibers with diameters as low as 40 nanometers and fluffy structures. The resultant electrospun webs' biocidal activities relative to the solution cast film samples and

Kazim Acatay; Mert Akel

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

Selective removal and inactivation of bacteria by nanoparticle composites prepared by surface modification of montmorillonite with quaternary ammonium compounds.  

PubMed

The purpose of the present study was to prepare new nanocomposites with antibacterial activities by surface modification of montmorillonite using quaternary ammonium compounds that are widely applied as disinfectants and antiseptics in food-processing environments. The intercalation of four quaternary ammonium compounds namely benzalkonium chloride, cetylpyridinium chloride monohydrate, hexadecyltrimethylammonium bromide, tetraethylammonium chloride hydrate into montmorillonite layers was confirmed by X-ray diffraction. The antibacterial influences of the modified clay variants against important foodborne pathogens differed based on modifiers quantities, microbial cell densities, and length of contact. Elution experiments through 0.1 g of the studied montmorillonite variants indicated that Staphylococcus aureus, Pseudomonas aeroginosa, and Listeria monocytogenes were the most sensitive strains. 1 g of hexadecyltrimethylammonium bromide intercalated montmorillonites demonstrated maximum inactivation of L. monocytogenes populations, with 4.5 log c.f.u./ml units of reduction. In adsorption experiments, 0.1 g of tetraethylammonium chloride hydrate montmorillonite variants significantly reduced the growth of Escherichia coli O157:H7, L. monocytogenes, and S. aureus populations by 5.77, 6.33, and 7.38 log units respectively. Growth of wide variety of microorganisms was strongly inhibited to undetectable levels (chloride montmorillonite variants. This investigation highlights that reduction in counts of microbial populations adsorbed to the new nanocomposites was substantially different from that in elution experiments, where interactions of nanocomposites with bacteria were specific and more complex than simple ability to inactivate. Treatment columns packed with modified variants maintained their inactivation capacity to the growth of Salmonella Tennessee and S. aureus populations after 48 h of incubation at room temperature with maximum reductions of 6.3 and 5.0 log units respectively. New nanocomposites presented in this research may have potential applications in industrial scale for the control of foodborne pathogens by their incorporation into high-performance filters in food processing plant environments where selectivity in removal and/or inactivation of species in fluid flow streams is desirable. Nevertheless, extensive in vitro and in vivo studies of these new nanocomposites is essential to outpace the understanding of their potential impacts and consequences on human health and the environment if they will make an appearance in commercialized food packaging and containment food materials in the future. PMID:23709187

Khalil, Rowaida K S

2013-10-01

78

Identification and characterization of quaternary ammonium compound resistant staphylococci from the food industry  

Microsoft Academic Search

The distribution of known genes conferring resistance to quaternary ammonium compounds (QACs) among different species of staphylococci isolated from the food industry was investigated. Twenty-four isolates hosting one of the genes qacA\\/qacB, smr, qacG or qacH, were subjected to species identification. Species determination was performed by biochemical analyses (API STAPH), comparative 16S rDNA sequence analysis and tDNA intergenic spacer length

Even Heir; Gunhild Sundheim; Askild L Holck

1999-01-01

79

HPLC Analysis of Mixtures of Acrylamide and Quaternary Ammonium Cationic Monomers  

Microsoft Academic Search

The HPLC separation of acrylamide from the quaternary ammonium cationic monomers dimethylaminoethyl acrylate and dimethylaminoethyl methacrylate has been investigated. It was found that a cyano-bonded silica stationary phase provided superior separations relative to an octyldecyl-bonded coated substrate. For either stationary phase, a binary mixture of acetonitrile and water gave far improved elution characteristics to a methanol-water mobile phase. An optimum

D. Hunkeler; H. Nl; J. Hernandez-barajas; M. Petro

1996-01-01

80

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

81

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

82

Compatibility of quaternary ammonium-based ionic liquid electrolytes with electrodes in lithium ion batteries  

Microsoft Academic Search

Electrochemical intercalation\\/deintercalation behavior of lithium into\\/from electrodes of lithium ion batteries was comparatively investigated in 1mol\\/L LiClO4 ethylene carbonate–diethyl carbonate (EC-DEC) electrolyte and a quaternary ammonium-based ionic liquid electrolyte. The natural graphite anode exhibited satisfactory electrochemical performance in the ionic liquid electrolyte containing 20vol.% chloroethylenene carbonate (Cl-EC). This is attributed to the mild reduction of solvated Cl-EC molecules at the

Honghe Zheng; Bao Li; Yanbao Fu; Takeshi Abe; Zempachi Ogumi

2006-01-01

83

Evaluation of three-dimensional biofilms on antibacterial bonding agents containing novel quaternary ammonium methacrylates  

PubMed Central

Antibacterial adhesives are promising to inhibit biofilms and secondary caries. The objectives of this study were to synthesize and incorporate quaternary ammonium methacrylates into adhesives, and investigate the alkyl chain length effects on three-dimensional biofilms adherent on adhesives for the first time. Six quaternary ammonium methacrylates with chain lengths of 3, 6, 9, 12, 16 and 18 were synthesized and incorporated into Scotchbond Multi-Purpose. Streptococcus mutans bacteria were cultured on resin to form biofilms. Confocal laser scanning microscopy was used to measure biofilm thickness, live/dead volumes and live-bacteria percentage vs. distance from resin surface. Biofilm thickness was the greatest for Scotchbond control; it decreased with increasing chain length, reaching a minimum at chain length 16. Live-biofilm volume had a similar trend. Dead-biofilm volume increased with increasing chain length. The adhesive with chain length 9 had 37% live bacteria near resin surface, but close to 100% live bacteria in the biofilm top section. For chain length 16, there were nearly 0% live bacteria throughout the three-dimensional biofilm. In conclusion, strong antibacterial activity was achieved by adding quaternary ammonium into adhesive, with biofilm thickness and live-biofilm volume decreasing as chain length was increased from 3 to 16. Antibacterial adhesives typically only inhibited bacteria close to its surface; however, adhesive with chain length 16 had mostly dead bacteria in the entire three-dimensional biofilm. Antibacterial adhesive with chain length 16 is promising to inhibit biofilms at the margins and combat secondary caries.

Zhou, Han; Weir, Michael D; Antonucci, Joseph M; Schumacher, Gary E; Zhou, Xue-Dong; Xu, Hockin HK

2014-01-01

84

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

85

Effects of particle size and chain length on flotation of quaternary ammonium salts onto kaolinite  

NASA Astrophysics Data System (ADS)

Effects of particle size and chain length on flotation of quaternary ammonium salts (QAS) onto kaolinite have been investigated by flotation tests. Dodecyltrimethylammonium chloride (DTAC) and cetyltrimethylammonium chloride (CTAC) were used as collectors for kaolinite in different particle size fractions (0.075 ~ 0.01 mm, 0.045 ~ 0.075 mm, 0 ~ 0.045 mm). The anomalous flotation behavior of kaolinite have been further explained based on crystal structure considerations by adsorption tests and molecular dynamics (MD) simulation. The results show that the flotation recovery of kaolinite in all different particle size fractions decreases with an increase in pH. As the concentration of collectors increases, the flotation recovery increases. The longer the carbon chain of QAS is, the higher the recoveries of coarse kaolinite (0.075 ~ 0.01 mm and 0.045 ~ 0.075 mm) are. But the flotation recovery of the finest kaolinite (0 ~ 0.045 mm) decreases with chain lengths of QAS collectors increasing, which is consistent with the flotation results of unscreened kaolinite (0 ~ 0.075 mm). It is explained by the froth stability related to the residual concentration of QAS collector in mineral pulp. In lower residual concentration, the froth stability becomes worse. Within the range of flotation collector concentration, it's easy of CTAC to be completely adsorbed by kaolinite in the particle size fraction (0-0.045 mm), which led to lower flotation recovery. Moreover, it is interesting that the coarser particle size of kaolinite is, the higher flotation recovery is. The anomalous flotation behavior of kaolinite is rationalized based on crystal structure considerations. The results of MD simulations show that the (001) kaolinite surface has the strongest interaction with DTAC, compared with the (001) face, (010) and (110) edges. On the other hand, when particle size of kaolinite is altered, the number of basal planes and edge planes is changed. It is observed that the finer kaolinite particles size become, the greater relative surface area of edges and the more the number of edges are. It means that fine kaolinite particles have more edges to adsorb fewer cationic colletors than that of coarse kaolinite particles, which is responsible for the poorer floatability of fine kaolinite.

Longhua, Xu; Yuehua, Hu; Faqin, Dong; Hao, Jiang; Houqin, Wu; Zhen, Wang; Ruohua, Liu

2014-05-01

86

Hibiscus sabdariffa Affects Ammonium Chloride-Induced Hyperammonemic Rats  

PubMed Central

Hibiscus sabdariffa (HS) is an edible medicinal plant, indigenous to India, China and Thailand and is used in Ayurveda and traditional medicine. Alcoholic extract of HS leaves (HSEt) was studied for its anti-hyperammonemic and antioxidant effects in brain tissues of ammonium chloride-induced hyperammonemic rats. Oral administration of HSEt (250 mg kg?1 body weight) significantly normalizes the levels of ammonia, urea, uric acid, creatinine and non-protein nitrogen in the blood. HSEt significantly reduced brain levels of lipid peroxidation products such as thiobarbituric acid and reactive substances (TBARS) and hydroperoxides (HP). However, the administered extract significantly increased the levels of antioxidants such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and reduced glutathione (GSH) in brain tissues of hyperammonemic rats. This investigation demonstrates significant anti-hyperammonemic and antioxidant activity of HS.

Essa, M. Mohamed

2007-01-01

87

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 organic species 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) ≥ 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 organic species 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.

2013-12-01

88

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

89

Fluoroponytailed crown ethers and quaternary ammonium salts as solid-liquid phase transfer catalysts in organic synthesis.  

PubMed

Fluorous derivatives of dibenzo-18-crown-6 ether were prepared, and then successfully applied in representative solid-liquid phase transfer catalysis reactions, which were performed in standard organic solvents, such as chlorobenzene and toluene, as well as in fluorous solvents, such as perfluoro-1,3-dimethylcyclohexane. It was clearly shown that properly designed fluoroponytailed crown ethers could promote the disintegration of the crystal lattice of alkali salts, and transfer anions from the solid surface into an apolar, non-coordinating perfluorocarbon phase, for phase transfer catalysis reactions in organic synthesis. Furthermore, 3,5-bis(perfluorooctyl)benzyl bromide and triethylamine were reacted under mild conditions to provide an analogue of the versatile phase transfer catalyst, benzyltriethylammonium chloride, containing two fluoroponytails. This fluoroponytailed quaternary ammonium salt was also successfully employed as a catalyst in a variety of organic reactions conducted under solid-liquid phase transfer catalysis conditions, without a perfluorocarbon phase. Thus, being both hydrophobic and lipophobic, fluorous crown ethers and ammonium salts, could be rapidly recovered in quantitative yields, and reused without loss of activity, over several reaction cycles. PMID:21928010

Pozzi, Gianluca; Fish, Richard H

2012-01-01

90

Mechanism of Osmotic Activation of the Quaternary Ammonium Compound Transporter (QacT) of Lactobacillus plantarum  

PubMed Central

The accumulation of quaternary ammonium compounds in Lactobacillus plantarum is mediated via a single transport system with a high affinity for glycine betaine (apparent Km of 18 ?M) and carnitine and a low affinity for proline (apparent Km of 950 ?M) and other analogues. Mutants defective in the uptake of glycine betaine were generated by UV irradiation and selected on the basis of resistance to dehydroproline (DHP), a toxic proline analogue. Three independent DHP-resistant mutants showed reduced glycine betaine uptake rates and accumulation levels but behaved similarly to the wild type in terms of direct activation of uptake by high-osmolality conditions. Kinetic analysis of glycine betaine uptake and efflux in the wild-type and mutant cells is consistent with one uptake system for quaternary ammonium compounds in L. plantarum and a separate system(s) for their excretion. The mechanism of osmotic activation of the quaternary ammonium compound transport system (QacT) was studied. It was observed that the uptake rates were inhibited by the presence of internal substrate. Upon raising of the medium osmolality, the QacT system was rapidly activated (increase in maximal velocity) through a diminished inhibition by trans substrate as well as an effect that is independent of intracellular substrate. We also studied the effects of the cationic amphipath chlorpromazine, which inserts into the cytoplasmic membrane and thereby influences the uptake and efflux of glycine betaine. The results provide further evidence for the notion that the rapid efflux of glycine betaine upon osmotic downshock is mediated by a channel protein that is responding to membrane stretch or tension. The activation of QacT upon osmotic upshock seems to be brought about by a turgor-related parameter other than membrane stretch or tension.

Glaasker, Erwin; Heuberger, Esther H. M. L.; Konings, Wil N.; Poolman, Bert

1998-01-01

91

Evaluation of three-dimensional biofilms on antibacterial bonding agents containing novel quaternary ammonium methacrylates.  

PubMed

Antibacterial adhesives are promising to inhibit biofilms and secondary caries. The objectives of this study were to synthesize and incorporate quaternary ammonium methacrylates into adhesives, and investigate the alkyl chain length effects on three-dimensional biofilms adherent on adhesives for the first time. Six quaternary ammonium methacrylates with chain lengths of 3, 6, 9, 12, 16 and 18 were synthesized and incorporated into Scotchbond Multi-Purpose. Streptococcus mutans bacteria were cultured on resin to form biofilms. Confocal laser scanning microscopy was used to measure biofilm thickness, live/dead volumes and live-bacteria percentage vs. distance from resin surface. Biofilm thickness was the greatest for Scotchbond control; it decreased with increasing chain length, reaching a minimum at chain length 16. Live-biofilm volume had a similar trend. Dead-biofilm volume increased with increasing chain length. The adhesive with chain length 9 had 37% live bacteria near resin surface, but close to 100% live bacteria in the biofilm top section. For chain length 16, there were nearly 0% live bacteria throughout the three-dimensional biofilm. In conclusion, strong antibacterial activity was achieved by adding quaternary ammonium into adhesive, with biofilm thickness and live-biofilm volume decreasing as chain length was increased from 3 to 16. Antibacterial adhesives typically only inhibited bacteria close to its surface; however, adhesive with chain length 16 had mostly dead bacteria in the entire three-dimensional biofilm. Antibacterial adhesive with chain length 16 is promising to inhibit biofilms at the margins and combat secondary caries. PMID:24722581

Zhou, Han; Weir, Michael D; Antonucci, Joseph M; Schumacher, Gary E; Zhou, Xue-Dong; Xu, Hockin Hk

2014-06-01

92

Temperature field measurements for a growing ammonium chloride mushy layer  

NASA Astrophysics Data System (ADS)

Experiments study the solidification from below of aqueous ammonium chloride. Thermochromic liquid crystal paints enable visualization of the temperature field in both the liquid and mushy regions. Spacetime plots of isotherm positions show the development of mushy-layer (plume) and boundary-layer (salt-finger) convection(M.G. Worster, J. Fluid Mech. 237), 649 (1992).. Boundary-layer convection is present in the fluid above the mushy layer at early times; whereas the larger-wavelength mushy-layer mode dominates over longer time scales. In a thin (Hele-Shaw) cell, plume evolution is compared to the development of chimneys in the mush. A coarsening mechanism is identified whereby a plume spontaneously decays, after which dendrites grow into the previously-empty channels, resulting in the demise of a chimney. In rare cases, two nearby plumes (and their channels) oscillate out of phase for several periods, evidence, perhaps, of an oscillatory instability predicted recently.(F. Chen, J.W. Wu and T. L. Yang, J. Fluid Mech. 276), 163 (1994). We also present studies of the effects of varying mush permeability on chimney formation. It is found experimentally that increases in mush permeability enhance chimney formation substantially.

Solomon, T. H.; Hartley, R. R.; Lee, A. T.

1996-11-01

93

Analysis of multiple quaternary ammonium compounds in the brain using tandem capillary column separation and high resolution mass spectrometric detection.  

PubMed

Endogenous quaternary ammonium compounds are involved in various physiological processes in the central nervous system. In the present study, eleven quaternary ammonium compounds, including acetylcholine, choline, carnitine, acetylcarnitine and seven other acylcarnitines of low polarity, were analyzed from brain extracts using a two dimension capillary liquid chromatography-Fourier transform mass spectrometry method. To deal with their large difference in hydrophobicities, tandem coupling between reversed phase and hydrophilic interaction chromatography columns was used to separate all the targeted quaternary ammonium compounds. Using high accuracy mass spectrometry in selected ion monitoring mode, all the compounds could be detected from each brain sample with high selectivity. The developed method was applied for the relative quantification of these quaternary ammonium compounds in three different brain regions of tree shrews: prefrontal cortex, striatum, and hippocampus. The comparative analysis showed that quaternary ammonium compounds were differentially distributed across the three brain areas. The analytical method proved to be highly sensitive and reliable for simultaneous determination of all the targeted analytes from brain samples. PMID:22533909

Falasca, Sara; Petruzziello, Filomena; Kretz, Robert; Rainer, Gregor; Zhang, Xiaozhe

2012-06-01

94

Quaternary ammonium salt derived thiadiazoles as multifunctional antioxidant and antiwear additives  

SciTech Connect

An improved liquid hydrocarbon fuel composition is described comprising a major proportion of said fuel and a minor proportion of a multifunctional antiwear, antioxidant, corrosion inhibiting and metal passivating additive product of reaction obtained by reacting (1) a thiadiazole derivative having one or two mercaptan functionalities with a quaternary ammonium salt and (2) the product thereof with an organic dibasic anhydride in substantially molar amounts at temperatures varying from ambient to about 150 C under ambient or autogenous pressures for a time sufficient to obtain the desired additive product of reaction.

Shihying Hsu; Horodysky, H.G.

1993-06-08

95

New quaternary ammonium polymers as antimicrobial agents. Part II. Alkylation products of linear aliphatic poly (aminodisulphides)  

Microsoft Academic Search

Two new polymeric disulphides containing t-amino groups in their main chain, namely poly[1,8-(3,6-dimethyl-3,6-diaza) octaine diyl disulphide] (5) and poly[1,8-(1,12-(3,10-dimethyl-3,10-diaza) dodecane diyl disulphide] (6) were prepared by the polyoxidation of 3,6-dimethyl-3,6-diazaoctane-1,8-dithiol (3) and 3,10-dimethyl-3,10-diazadodecane-1,12-dithiol (4), respectively. They were quaternized with methyl iodide and benzyl bromide, and the resulting quaternary ammonium polymers were preliminarily tested for antimicrobial activity against Escherichia coli K12,

Elisabetta Ranucci; Paolo Ferruti; Maria Grazia Neri

1991-01-01

96

Reversible phase transformation-type layer shape electrolyte based on POM and quaternary ammonium salt  

NASA Astrophysics Data System (ADS)

A novel kind of organic-inorganic layer shape material, polyoxymetalates (POM)-type ionic liquid (IL) with Keggin structure and simple quaternary ammonium salt, (TOAMe)4PW11VO40 (trioctylmethylammonium = TOAMe,…) is synthesized and characterized by IR, UV, X-ray diffraction (XRD), TG-DTA. Its electrochemical property was investigated by cyclic voltammgram. Research results released the vanadium and the POM structure in the compound can process reduction in DMSO, which is unlikely in water solution as a simple hydrated ion because water will protonize substrate.

Wu, Xuefei; Li, Yunyan; Wu, Qingyin; Ding, Hong; Yan, Wenfu

2014-02-01

97

Development of highly diastereo- and enantioselective direct asymmetric aldol reaction of a glycinate Schiff base with aldehydes catalyzed by chiral quaternary ammonium salts.  

PubMed

A highly efficient direct asymmetric aldol reaction of a glycinate Schiff base with aldehydes has been achieved under mild organic/aqueous biphasic conditions with excellent stereochemical control, using chiral quaternary ammonium salt 1b as a phase-transfer catalyst. The initially developed reaction conditions, using 2 equiv of aqueous base (1% NaOH (aq)), exhibited inexplicably limited general applicability in terms of aldehyde acceptors. The mechanistic investigation revealed the intervention of an unfavorable yet inevitable retro aldol process involving the chiral catalyst. On the basis of this information, a reliable procedure has been established by use of a catalytic amount of 1% NaOH (aq) and ammonium chloride, which tolerates a wide range of aldehydes to afford the corresponding anti-beta-hydroxy-alpha-amino esters almost exclusively in an essentially optically pure form. PMID:15291572

Ooi, Takashi; Kameda, Minoru; Taniguchi, Mika; Maruoka, Keiji

2004-08-11

98

Reduction of quaternary ammonium-induced ocular surface toxicity by emulsions: an in vivo study in rabbits  

PubMed Central

Purpose To evaluate and compare the toxicological profiles of two quaternary ammonium compounds (QAC), benzalkonium chloride (BAK), and cetalkonium chloride (CKC), in standard solution or cationic emulsion formulations in rabbit eyes using newly developed in vivo and ex vivo experimental approaches. Methods Seventy eyes of 35 adult male New Zealand albino rabbits were used in this study. They were randomly divided into five groups: 50 µl of phosphate-buffered saline (PBS), PBS containing 0.02% BAK or 0.002% CKC (BAK Sol and CKC Sol, respectively), and emulsion containing 0.02% BAK or 0.002% CKC (BAK Em and CKC Em, respectively) were applied to rabbit eyes 15 times at 5-min intervals. The ocular surface changes induced by these eye drops were investigated using slit-lamp examination, flow cytometry (FCM), impression cytology (IC) on conjunctiva, and corneal in vivo confocal microscopy (IVCM). Standard immunohistology in cryosections was also examined for cluster of differentiation (CD) 45+ infiltrating and terminal deoxynucleotidyl transferase-mediated dUTP-nick end labeling (TUNEL)+ apoptotic cells. Results Clinical observations and IVCM showed that the highest toxicity was induced by BAK Sol, characterized by damaged corneal epithelium and a high level of inflammatory infiltration. BAK Em and CKC Sol presented moderate effects, and CKC Em showed the lowest toxicity with results similar to those of PBS. Conjunctival imprints analyzed by FCM showed a higher expression of RLA-DR and TNFR1 markers in BAK Sol-instilled eyes than in all other groups, especially at 4 h. Immunohistology was correlated with in vivo and ex vivo findings and confirmed this toxicity profile. A high level of infiltration of CD45+ inflammatory cells and TUNEL+ apoptotic cells was observed in limbus and conjunctiva, especially in QAC solution-receiving eyes compared to QAC emulsion-instilled eyes. Conclusions The acute administration of 15 instillations at 5 min intervals was a rapid and efficient model to assess quaternary ammonium toxicity profiles. This model showed the highest toxicity, induced by the BAK solution, and the lowest level of toxicity, induced by the CKC emulsion. These in vivo and ex vivo experimental approaches demonstrated that ocular surface toxicity was reduced by using an emulsion instead of a traditional solution and that a CKC emulsion was safe for future ocular administration.

Liang, H.; Brignole-Baudouin, F.; Rabinovich-Guilatt, L.; Mao, Z.; Riancho, L.; Faure, M.O.; Warnet, J.M.; Lambert, G.

2008-01-01

99

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

100

21 CFR 520.310 - Caramiphen ethanedisulfonate and ammonium chloride tablets.  

Code of Federal Regulations, 2013 CFR

...contains 10 milligrams of 5st caramiphen ethanedisulfonate and 80 milligrams of ammonium chloride.1 1 These conditions are NAS/NRC reviewed and deemed effective. Applications for these uses need not include effectiveness data as specified by §...

2013-04-01

101

Reductive Coupling of Carbonyl Compounds to Pinacols with Zinc in THF Saturated Aqueous Ammonium Chloride  

Microsoft Academic Search

Summary.  ?In the presence of metallic zinc, aldehydes and ketones experience reductive coupling in tetrahydrofuran-saturated aqueous\\u000a ammonium chloride (5:3) to afford the corresponding pinacols in moderate to high yields.

Rahim Hekmatshoar; Issa Yavari; Yahya S. Beheshtiha; Majid M. Heravi

2001-01-01

102

New quaternary ammonium oxicam derivatives targeted toward cartilage: synthesis, pharmacokinetic studies, and antiinflammatory potency.  

PubMed

Analogues of nonsteroidal antiinflammatory drugs (NSAIDs) oxicams, in which the active group was linked to a quaternary ammonium function [(4-hydroxy-2-methyl-2H-1,2-benzothiazine-1, 1-dioxide-3-carboxamido)2-methylpyridinium iodide or piroxicam-N(+) and [3-(4-hydroxy-2-methyl-2H-1,2-benzothiazine-1, 1-dioxide-3-carboxamido)propyl]trimethylammonium iodide or propoxicam-N(+)] were synthesized. Compounds were labeled with tritium for piroxicam-N(+) and carbon-14 for propoxicam-N(+). Pharmacokinetic studies conducted on rats showed that these molecules were able to highly concentrate in joint cartilages but their bioavailability by the oral way was low. Only propoxicam-N(+) exhibited a sufficient water solubility to be administered intravenously. This molecule was able to restore proteoglycans biosynthesis in cultured articular chondrocytes treated with Interleukin-1beta with an efficiency identical to that of indomethacin. These results suggest that the functionalization of oxicam derivatives by a quaternary ammonium group greatly increases their affinity toward articular cartilage without eliminating their pharmacological activity. New drugs synthesized according to this scheme could be useful to obtain a significant decrease of the efficient administered dose and consequently an attenuation of adverse effects such as digestive toxicity. PMID:10602708

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

1999-12-16

103

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

104

Ion Exchange Behavior of Natural Zeolites in Distilled Water, Hydrochloric Acid, and Ammonium Chloride Solution  

Microsoft Academic Search

This study presents basic research on the use of natural zeolites for the removal of ammonium ions from aqueous solutions. Three natural zeolites from Shimane, Japan, used in this study are shown to contain varying amounts of clinoptilolite and mordenite. The chemical behavior of these natural zeolites was investigated in distilled water, hydrochloric acid, and ammonium chloride solution. The amount

Yujiro Watanabe; Hirohisa Yamada; Hisao Kokusen; Junzo Tanaka; Yusuke Moriyoshi; Yu Komatsu

2003-01-01

105

Aggregation and chimney formation during the solidification of ammonium chloride.  

PubMed

Experiments study large-scale pattern formation during the growth of ammonium chloride (NH4Cl) from solution in a thin (Hele-Shaw) geometry. In particular a solid-liquid mixture ("mushy layer") forms in which growing solid NH4Cl crystals form a solid network interspersed with liquid. There are different ways that the mushy layer can be formed, however. If the cell is heated from below and cooled from above, thermal convection generates large-scale recirculating flows that carry seed crystals from the upper (cold) boundary to the (warmer) side and bottom boundaries. Ballistic deposition of these seed crystals leads to aggregation patterns with significant voids (filled with liquid) with a wide range of length scales. If the cell is cooled from below with a warm environment, the solid NH4Cl grows dendritically without deposition, resulting in a compact mushy layer. Plume convection within this mushy layer produces one or two well-defined "chimneys." If the environment is cool (comparable to the liquidus temperature of the solution), the mushy layer forms by a combination of dendritic growth and ballistic deposition, resulting in a more permeable mushy layer and enhanced chimney formation. The effects of ballistic deposition are enhanced if the cell is tipped, in which case the voids reappear. Plume convection and chimney formation are dramatically enhanced in this case. Additional experiments are done in which fluid flows in the system are enhanced artificially to verify that enhancements in chimney formation are due primarily to the aggregation process, and not to the increases in fluid flows due to thermal and compositional convection. PMID:11970113

Solomon, T H; Hartley, R R; Lee, A T

1999-09-01

106

Capillary electrophoresis with detection by inverse UV spectroscopy and electrospray mass spectrometry for the examination of quaternary ammonium herbicides  

Microsoft Academic Search

The value of capillary electrophoresis (CE) and combined capillary electrophoresis-electrospray mass spectrometry (CE-ES-MS) for the analysis of simple quaternary ammonium ions, including herbicides, has been assessed. Choline, chlormequat, known contaminants of their formulation products, and some other small ammonium cations have been examined. Lacking a chromophore, the cations were detected by inverse UV absorption utilizing a buffer containing creatinine as

Darren Wycherley; Malcolm E. Rose; Kevin Giles; Therese M. Hutton; Duncan A. Rimmer

1996-01-01

107

Sorption of quaternary ammonium compounds in soils: implications to the soil microbial activities.  

PubMed

Despite their widespread use in household activities and various industries, information on the toxicity of quaternary ammonium compounds (QACs) to microbial activities in soil is scant. This study investigated the effect of three commonly used QACs namely hexadecyltrimethyl ammonium bromide (HDTMA), octadecyltrimethyl ammonium bromide (ODTMA) and Arquad on dehydrogenase and potential nitrification activities in three different soils. The toxicity of QACs on the dehydrogenase activity and potential nitrification in these soils followed the order: HDTMA>ODTMA>Arquad and Arquad>HDTMA>ODTMA, respectively. HDTMA, ODTMA and Arquad exhibited toxicity to dehydrogenase activity at concentration of 50, 100 and 750 mg kg(-1) soil, respectively, whereas potential nitrification was inhibited by HDTMA and ODTMA even at 50 mg kg(-1) soil. Arquad exhibited toxicity to potential nitrification at comparatively higher concentration of 250 mg kg(-1) soil, with the severity of toxicity very intense at higher concentrations. The nature of QACs and soil properties influenced the toxicity. The toxic effect of QACs on soil microbial activities was more influenced by the relative release of sorbed QACs in soils. This study provides valuable information on the toxicological properties of some widely used QACs on important soil microbial activity parameters. To our knowledge, this is the first report. PMID:20855157

Sarkar, Binoy; Megharaj, Mallavarapu; Xi, Yunfei; Krishnamurti, G S R; Naidu, Ravi

2010-12-15

108

Extraction-spectrophotometric determination of aluminium in river water with pyrocatechol violet and a quaternary ammonium salt.  

PubMed

The simple removal of excess of co-extracted reagent in the solvent extraction of anionic metal complexes with a quaternary ammonium salt greatly improves the determination of aluminium with Pyrocatechol Violet (PV) and zephiramine (tetradecyldimethylbenzylammonium chloride). The exchange equilibrium constants for PV reagent and aluminium complex with four univalent anions (halides and nitrate) were determined when chloroform and 1,2-dichloroethane were used as extracting solvents. The constants were compared with those obtained with Pyrogallol Red. The method with PV and chloroform is suitable for the determination of micro-amounts of aluminium in river water. The apparent molar absorptivity of the aluminium complex in chloroform is 8.9 x 10(4) 1 mol(-1) cm(-1) at 587 nm. The limit of detection and precision achieved with the method are 3 mug l(-1) and within 4% respectively. A large excess of reagent can be used, and the ternary complex can be completely extracted over the pH range 5.5-10. Masking agents allow most interferences to be suppressed. PMID:18962608

Korenaga, T; Motomizu, S; Tôei, K

1980-01-01

109

Adaptation of Pseudomonas sp. strain 7-6 to quaternary ammonium compounds and their degradation via dual pathways.  

PubMed

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. PMID:17261523

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

2007-03-01

110

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

111

Ion-exchange properties and electrochemical characterization of quaternary ammonium-functionalized silica microspheres obtained by the surfactant template route.  

PubMed

Porous silica spheres functionalized with quaternary ammonium groups have been prepared by co-condensation of N-((trimethoxysilyl)propyl)-N,N,N-trimethylammonium chloride (TMTMAC) and tetraethoxysilane (TEOS) in the presence of cetyltrimethylammonium as a template and ammonia as a catalyst. The physicochemical characteristics of the resulting ion exchangers have been analyzed by various techniques and discussed with respect to the amount of organofunctional groups in the materials. For comparison purposes, both an ordered MCM-41 type mesoporous silica and two silica gels of different pore size have been grafted with TMTMAC. The ion-exchange capabilities were first evaluated from batch experiments (determination of anion-exchange capacities) and then by ion-exchange voltammetry at carbon paste electrodes modified with these hybrid materials. Effective concentration of Fe(CN)(6)(3)(-) species in the anion exchangers was pointed out, while no significant accumulation of Ru(NH(3))(6)(3+) was observed. The preconcentration efficiency was discussed on the basis of the organic group content in the materials as well as their structure and porosity. A second series of materials displaying zwitterionic surfaces was finally prepared and characterized with respect to their physicochemical properties and ion-exchange voltammetric behavior. They consisted of sulfonic acid-functionalized mesoporous silica samples resulting from the oxidation of thiol-functionalized silica spheres obtained by co-condensation of mercaptopropyl-trimethoxysilane (MPTMS) and TEOS, which were then grafted with TMTMAC at various functionalization levels. Possible interactions between the ammonium and sulfonate moieties in the confined medium were pointed out from X-ray photoelectron spectroscopy. The competitive accumulation-rejection of Fe(CN)(6)(3)(-) and Ru(NH(3))(6)(3+) redox probes was finally studied by cyclic voltammetry. PMID:16378461

Walcarius, Alain; Ganesan, Vellaichamy

2006-01-01

112

Combined hydrous ferric oxide and quaternary ammonium surfactant tailoring of granular activated carbon for concurrent arsenate and perchlorate removal.  

PubMed

Activated carbon was tailored with both iron and quaternary ammonium surfactants so as to concurrently remove both arsenate and perchlorate from groundwater. The iron (hydr)oxide preferentially removed the arsenate oxyanion but not perchlorate; while the quaternary ammonium preferentially removed the perchlorate oxyanion, but not the arsenate. The co-sorption of two anionic oxyanions via distinct mechanisms has yielded intriguing phenomena. Rapid small-scale column tests (RSSCTs) with these dually prepared media employed synthetic waters that were concurrently spiked with arsenate and perchlorate; and these trial results showed that the quaternary ammonium surfactants enhanced arsenate removal bed life by 25-50% when compared to activated carbon media that had been preloaded merely with iron (hydr)oxide; and the surfactant also enhanced the diffusion rate of arsenate per the Donnan effect. The authors also employed natural groundwater from Rutland, MA which contained 60 microg/L As and traces of silica, and sulfate; and the authors spiked this with 40 microg/L perchlorate. When processing this water, activated carbon that had been tailored with iron and cationic surfactant could treat 12,500 bed volumes before 10 microg/L arsenic breakthrough, and 4500 bed volumes before 6 microg/L perchlorate breakthrough. Although the quaternary ammonium surfactants exhibited only a slight capacity for removing arsenate, these surfactants did facilitate a more favorably positively charged avenue for the arsenate to diffuse through the media to the iron sorption site (i.e. via the Donnan effect). PMID:19476961

Jang, Min; Cannon, Fred S; Parette, Robert B; Yoon, Soh-Joung; Chen, Weifang

2009-07-01

113

Influence of concentration and structure of quaternary ammonium salts on their antifouling efficiency tested against a community of marine bacteria  

Microsoft Academic Search

With the view of incorporating quaternary ammonium salts (QAs) in marine paints, nineteen of these were tested against a community of marine bacteria, at a temperature and salinity close to those of seawater. The concentration of QAs and the length of the main substituting chain are the main parameters affecting the growth and adhesion of bacteria, but the nature of

F. Baudrion; A. Perichaud; E. Vacelet

2000-01-01

114

Effect of quaternary ammonium cation loading and pH on heavy metal sorption to Ca bentonite and two organobentonites  

Microsoft Academic Search

Sorption of four heavy metals (Pb, Cd, Zn and Hg) to calcium bentonite (Ca bentonite), hexadecyltrimethylammonium bentonite (HDTMA bentonite) and benzyltriethylammonium bentonite (BTEA bentonite) was measured as a function of the quaternary ammonium cation (QAC) loading at 25, 50 and 100% of the clay's cation-exchange capacity (CEC). The effects of pH on the surface charge of the clays and heavy

Vinka A. Oyanedel-Craver; James A. Smith

2006-01-01

115

Sorption studies of chromium(VI) onto new ion exchanger with tertiary amine, quaternary ammonium and ketone groups  

Microsoft Academic Search

A new acrylic anion exchanger with both tertiary and quaternary ammonium as well as ketone groups in the structural unit has been prepared by the nucleophilic substitution reaction of aminolyzed vinylacetate:acrylonitrile:divinylbenzene copolymer of porosity structure in the swelling state with 2-chloroacetone as a halogenated compound. The new compound exhibits better qualities of strong base exchange capacity than the weak base

Grzegorz Wójcik; Violeta Neagu; Ion Bunia

2011-01-01

116

Solution-processed white organic light-emitting diodes with enhanced efficiency by using quaternary ammonium salt doped conjugated polyelectrolyte.  

PubMed

Solution-processed white organic light emitting diodes (WOLEDs) with quaternary ammonium salt doped water/alcohol soluble conjugated polyelectrolyte, poly[(9,9-bis(3'-((N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluoren)] dibromide (PFNBr), as electron transport material has been fabricated. Compared with the undoped devices, the performances of such devices with a doped electron transport layer have been dramatically improved to be nearly twice high in luminous efficiency and nearly one-third in response time when the weight ratio of PFNBr to tetraethylammonium bromide (TEAB) was 10:3. Four kinds of quaternary ammonium salts have been investigated to be dopants in the conjugated polyelectrolyte electron transport layer. It has been shown that both the anions and the cations of quaternary ammonium salts can influence the device performance. The dopant who has both a smaller anion and a smaller cation size can exhibit a better device performance. In addition, ultraviolet photoelectron spectroscopy measurement and single-carrier device testing have been employed to investigate the reason why such quaternary ammonium salt dopants can make an obvious improvement in the device performance of WOLEDs. These findings will be beneficial to the progress in design and fabrication of solution-processed WOLEDs suitable for lighting. PMID:24786821

Tian, Yuan; Xu, Xinjun; Wang, Jinshan; Yao, Chuang; Li, Lidong

2014-06-11

117

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

118

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

119

Effect of ten quaternary ammonium cations on tetrachloromethane sorption to clay from water  

SciTech Connect

The mineral surface of Wyoming bentonite (clay) was modified by replacing inorganic ions by each of 10 quaternary ammonium compounds, and tetrachloromethane sorption to the modified sorbents from water was studied. Tetrachloromethane sorption from solution to clay modified with tetramethyl-, tetraethyl-, benzyltrimethyl-, or benzyltriethylammonium cations generally is characterized by relatively high solute uptake, isotherm nonlinearity, and competitive sorption (with trichloroethene as the competing sorbate). For these sorbents, the ethyl functional groups yield reduced sorptive capacity relative to methyl groups, whereas the benzyl group appears to have a similar effect on sorbent capacity as the methyl group. Sorption of tetrachloromethane to clay modified with dodecyldimethyl(2-phenoxyethyl)-, dodecyltrimethyl-, tetradecyltrimethyl-, hexadecyltrimethyl-, or benzyldimethylhexadecylammonium bromide is characterized by relatively low solute uptake, isotherm linearity, and noncompetitive sorption. For these sorbents, an increase in the size of the nonpolar functional group(s) causes an increase in the organic carbon normalized sorption coefficient (K{sub oc}).

Smith, J.A. (Geological Survey, Trenton, NJ (USA)); Jaffe, P.R. (Princeton Univ., NJ (USA)); Chiou, C.T. (Geological Survey, Denver, CO (USA))

1990-08-01

120

Bio-based ionic liquid crystalline quaternary ammonium salts: properties and applications.  

PubMed

In the present work, we describe the preparation, properties, and applications of novel ionic liquid crystalline quaternary ammonium salts (QSs) of 3-pentadecylphenol, a bio-based low-cost material derived from cashew nut shell liquid. Amphotropic liquid crystalline phase formation in QSs was characterized using a combination of techniques, such as DSC, PLM, XRD, SEM, and rheology, which revealed the formation of one, two, and three dimensionally ordered mesophases in different length scales. On the basis of these results, a plausible mechanism for the formation of specific modes of packing in various mesophases was proposed. Observation of anisotropic ionic conductivity and electrochemical stability suggests their application as a solid electrolyte. PMID:24571658

Sasi, Renjith; Rao, Talasila P; Devaki, Sudha J

2014-03-26

121

Synthesis and characterization of dimethacrylates containing quaternary ammonium functionalities for dental applications  

PubMed Central

Objectives The widespread incidence of recurrent caries highlights the need for improved dental restorative materials. The objective of this study was to synthesize low viscosity ionic dimethacrylate monomers (IDMAs) that contain quaternary ammoniums groups (antimicrobial functionalities) and are compatible with existing dental dimethacrylate-based monomers. Such monomers have the potential to copolymerize with other methacrylate monomers and produce antibacterial polymers. Methods Two monomers (IDMA-1 and IDMA-2) were synthesized using the Menschutkin reaction and incorporated at 0% to 30% (by mass) into a 1:1 (by mass) bisphenol A glycerolate dimethacrylate (BisGMA):triethylene glycol dimethacrylate (TEGDMA) resin. Resin viscosity was quantified using rheology, and polymer degree of conversion (DC) and surface charge density were measured using Fourier transform infrared spectroscopy (FTIR) and fluorescein binding, respectively. Effects of IDMA-1 on initial attachment of Streptococcus mutans and on viability and enzymatic activity (formazan reduction) of RAW 264.7 macrophage-like cells were quantified. Results IDMA-1 and IDMA-2 were prepared and characterized. IDMA-1 was miscible with BisGMA:TEGDMA and slightly increased the resin viscosity and DC. As expected, polymeric surface charge density increased with increasing IDMA-1. Incorporation of 10% IDMA-1 into BisGMA:TEGDMA reduced bacterial colonization without affecting viability or enzymatic activity of mammalian cells. Increasing IDMA-1 up to 30% had no additional effect on bacterial coverage, but ? 20% IDMA-1 significantly reduced macrophage density, viability, and enzymatic activity. Leachables from polymers containing IDMA-1 were not cytotoxic. Significance The Menschutkin reaction provides a facile, convenient means to synthesize new monomers with quaternary ammonium groups for dental and medical applications.

Antonucci, Joseph M.; Zeiger, Diana N.; Tang, Kathy; Lin-Gibson, Sheng; Fowler, Bruce O.; Lin, Nancy J.

2011-01-01

122

Bis(tribenzyl-ammonium) tetra-chloridoaurate(III) chloride  

PubMed Central

In the title compound, (C21H22N)2[AuCl4]Cl, the AuIII atom adopts a square-planar coordination geometry defined by four chloride ions. In the crystal structure, inter­molecular N—H?Cl hydrogen bonds link the organic cations and the uncoordinated chloride ion.

Fazaeli, Yousef; Amani, Vahid; Amini, Mostafa M.; Khavasi, Hamid Reza

2010-01-01

123

Effect of ten quaternary ammonium cations on tetrachloromethane sorption to clay from water  

USGS Publications Warehouse

The mineral surface of Wyoming bentonite (clay) was modified by replacing inorganic ions by each of 10 quaternary ammonium compounds, and tetrachloromethane sorption to the modified sorbents from water was studied. Tetrachloromethane sorption from solution to clay modified with tetramethyl-, tetraethyl-, benzyltrimethyl-, or benzyltriethylammonium cations generally is characterized by relatively high solute uptake, isotherm nonlinearity, and competitive sorption (with trichloroethene as the competing sorbate). For these sorbents, the ethyl functional groups yield reduced sorptive capacity relative to methyl groups, whereas the benzyl group appears to have a similar effect on sorbent capacity as the methyl group. Sorption of tetrachloromethane to clay modified with dodecyldimethyl(2-phenoxyethyl)-, dodecyltrimethyl-, tetradecyltrimethyl-, hexadecyltrimethyl-, or benzyldimethylhexadecylammonium bromide is characterized by relatively low solute uptake, isotherm linearity, and noncompetitive sorption. For these sorbents, an increase in the size of the nonpolar functional group(s) causes an increase in the organic carbon normalized sorption coefficient (Koc). No measurable uptake of tetrachloromethane sorption by the unmodified clay or clay modified by ammonium bromide was observed. ?? 1990 American Chemical Society.

Smith, J. A.

1990-01-01

124

Pongamia pinnata modulates the oxidant-antioxidant imbalance in ammonium chloride-induced hyperammonemic rats.  

PubMed

The effect of Pongamia pinnata (an indigenous plant used in Ayurvedic Medicine in India) leaf extract (PPEt) on circulatory lipid peroxidation and antioxidant status was evaluated in ammonium chloride-induced hyperammonemic rats. Enhanced lipid peroxidation in the circulation of ammonium chloride-treated rats was accompanied by a significant decrease in the levels of vitamin A, vitamin C, vitamin E, reduced glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT). PPEt-administered rats experienced a significant reduction in lipid peroxidation with a simultaneous elevation in antioxidant levels. Our results indicate that PPEt modulates these changes by reversing the oxidant-antioxidant imbalance during ammonium chloride-induced hyperammonemia and this could be due to its (i) antihyperammonemic effect by means of detoxifying excess ammonia, urea and creatinine and (ii) antioxidant property. The exact mechanism has to be still investigated and isolation of active constituents is required. PMID:16671965

Essa, M Mohamed; Subramanian, P

2006-06-01

125

Fetal abnormalities produced after preimplantation exposure of mouse embryos to ammonium chloride  

Microsoft Academic Search

BACKGROUND: The aims of this study were to determine whether preimplantation exposure of mouse embryos to ammonium resulted in abnormal fetal development and to evaluate similar risks to the outcome of human assisted conception. METHODS: Mouse embryos cultured from the 1-cell stage were exposed to 0.3 mmol\\/l ammonium chloride for 3 days. Embryos cultured from the 2-cell stage were exposed

Supat Sinawat; Wei-Chih Hsaio; Jean H. Flockhart; Matthew H. Kaufman; John Keith; John D. West

2003-01-01

126

Ethyl-enedi-ammonium chloride thio-cyanate  

PubMed Central

In the ethyl­enedi­ammonium dication of the title salt, C2H10N2 2+·Cl?·SCN?, the N—C—C—N torsion angle is 72.09?(12)°. In the crystal, an extensive three-dimensional hydrogen-bonding network, formed by N—H?Cl and N—H?N hydrogen bonds, holds all the ions together.

Karoui, Sahel; Kamoun, Slaheddine; Michaud, Francois

2013-01-01

127

Quaternary ammonium chitosan derivative dynamic coating for the separation of veterinary sulfonamide residues by CE with field-amplified sample injection.  

PubMed

A quaternary ammonium chitosan, 2-hydroxypropyltrimethylammonium chloride chitosan (HACC), has been developed for the dynamic coating material in CE for the first time. It presented many advantages such as favorable water solubility, satisfactory coating efficiency, and EOF toward the anode at pH >7.0. Using the modified fused-silica capillary, sulfonamides (SAs), an important group of veterinary drugs, were separated and detected by CE combined with field-amplified sample injection (FASI). The LODs of sulfonamides with UV detection were less than 0.5 ng/mL. The proposed method has been applied to the determination of veterinary sulfonamide residues in samples such as chicken, beef, and honey with fast separation (15 sulfonamides within 20 min), low LODs (0.1-0.5 ng/mL), and good reliability compared to the criteria of China (GB/T 18932.17-2003). PMID:17960537

Ma, Ming; Zhang, Hua-Shan; Xiao, Ling-Yan; Xiao, Ling; Wang, Peng; Cui, Hai-Rong; Wang, Hong

2007-11-01

128

Genetic linkage between resistance to quaternary ammonium compounds and beta-lactam antibiotics in food-related Staphylococcus spp.  

PubMed

Little is known about the occurrence of antimicrobial resistance determinants in staphylococci isolated from food and food processing industries. Quaternary ammonium compound (QAC)-resistant coagulase-negative staphylococci (CNS) isolated from food and food-processing industries were investigated for the presence of genetic determinants (qacA/B and qacC/smr) encoding resistance to the QAC benzalkonium chloride (BC), several antibiotic resistance genes, and staphylococcal insertion sequences IS257 and IS256. Six qacA/B-harboring strains were resistant to penicillin and hybridized to a blaZ probe. The qacA/B and blaZ probes hybridized to plasmids of similar size in three isolates. Molecular and genetic characterization of the 23-kb plasmid (pST6) of Staphylococcus epidermidis St.6 revealed the presence of qacB adjacent to an incomplete beta-lactamase transposon Tn552 encoding the gene cluster blaZ, blaR, and blaI. Sequence analysis of flanking regions and the intergenic region between blaZ and qacB revealed the presence of IS257 downstream of blaZ as well as sin and binR between blaZ and qacB. In the three other BC and penicillin-resistant strains, the qacA/B and blaZ genes were located on separate plasmids. A qacC harboring S. epidermidis strain (St.17) also hybridized to tetK (tetracycline resistance) and ermB (erythromycin resistance) genes. The individual genes were located on separate plasmids, suggesting no linkage between QAC and antibiotic resistance determinants. Plasmid-free Staphylococcus aureus RN4220 allowed uptake of the pST6 plasmid DNA, indicating that the resistance genes could potentially be transferred to pathogens under selective stress. In conclusion, presence of both resistance determinants could lead to co-selection during antimicrobial therapy or disinfection in hospitals or in food industries. PMID:11822776

Sidhu, M S; Heir, E; Sørum, H; Holck, A

2001-01-01

129

The effect of the ionic size of small quaternary ammonium BF4 salts on electrochemical double layer capacitors.  

PubMed

By varying the cation size of quaternary ammonium salts, approximately 10% higher capacitance was achieved with trimethylethylammonium BF4 and trimethylpropylammonium BF4 relative to tetraethylammonium BF4 using microporous activated carbon (AC) electrodes. The ions carried solvation shells in the bulk electrolytes, but became desolvated within the narrow AC pores when the electrochemical double-layer capacitor was charged to a high potential. The capacitance depended on the size of the cation rather than that of the BF4 anion because the anion is smaller than the quaternary ammonium ions. The capacitance was found to be proportional to the reciprocal radii of the neat cations. The effective radius of the asymmetric trimethylpropylammonium ion was estimated to be 0.314 nm based on the present results. PMID:24935222

Koh, Ah Reum; Hwang, Byunghyun; Chul Roh, Kwang; Kim, Ketack

2014-07-01

130

Permeability of a polyurethane membrane, Halthane 73-18, to aqueous ammonium chloride  

Microsoft Academic Search

Conclusions of this study are (1) that a thin Halthane 73-18 film is not permeable to NHâCl from a concentrated solution, and (2) that an intact Halthane coating on TATB would almost certainly protect metals adjacent to the explosive from attack by ammonium chloride.

Leider

1978-01-01

131

Permeability of a polyurethane membrane, Halthane 73-18, to aqueous ammonium chloride  

Microsoft Academic Search

Conclusions reached in this study are that a thin Halthane 73-18 film is not permeable to NHâC1 from a concentrated solution, and that an intact Halthane coating on TATB would almost certainly protect metals adjacent to the explosive from attack by ammonium chloride.

Leider

1978-01-01

132

New multilayer coating using quaternary ammonium chitosan and ?-carrageenan in capillary electrophoresis: Application in fast analysis of betaine and methionine.  

PubMed

The aim of this study was to develop a new multilayer coating with crosslinked quaternary ammonium chitosan (hydroxypropyltrimethyl ammonium chloride chitosan; HACC) and ?-carrageenan for use in capillary electrophoresis. A new semi-permanent multilayer coating was formed using the procedure developed and the method does not require the presence of polymers in the background electrolyte (BGE). The new capillary multilayer coating showed a cathodic electroosmotic flow (EOF) of around 30×10(-9)m(2)V(-1)s(-1) which is pH-independent in the range of pH 2 to 10. The enhanced EOF at low pH obtained contributed significantly to the development of a fast method of separation. The multilayer coating was then applied in the development of a fast separation method to determine betaine and methionine in pharmaceutical formulations by capillary zone electrophoresis (CZE). The BGE used to determine the betaine and methionine concentrations was composed of 10mmolL(-1) tris(hydroxymethyl) aminomethane, 40mmolL(-1) phosphoric acid and 10% (v/v) ethanol, at pH 2.1. A fused-silica capillary of 32cm (50µm ID×375µm OD) was used in the experiments and samples and standards were analyzed employing the short-end injection procedure (8.5cm effective length). The instrumental analysis time of the optimized method was 1.53min (approx. 39 runs per hour). The validation of the proposed method for the determination of betaine and methionine showed good linearity (R(2)>0.999), adequate limit of detection (LOD <8mgL(-1)) for the concentration in the samples and inter-day precision values lower than 3.5% (peak area and time migration). The results for the quantification of the amino acids in the samples determined by the CZE-UV method developed were statistically equal to those obtained with the comparative LC-MS/MS method according to the paired t-test with a confidence level of 95%. PMID:24725863

Vitali, Luciano; Della Betta, Fabiana; Costa, Ana Carolina O; Vaz, Fernando Antonio Simas; Oliveira, Marcone Augusto Leal; Pereira Vistuba, Jacqueline; Fávere, Valfredo T; Micke, Gustavo A

2014-06-01

133

Prediction of copolymer composition drift using artificial neural networks: copolymerization of acrylamide with quaternary ammonium cationic monomers  

Microsoft Academic Search

The free radical copolymerization of acrylamide with a quaternary ammonium cationic comonomer, diethylaminoethyl acrylate (DMAEA), has been investigated in inverse-emulsion. The copolymer composition was determined from residual monomer concentrations using an h.p.l.c. method. Both reactivity ratios were observed to change with conversion. Furthermore, the reactivity ratio of the cationic monomer was found to be a function of the ionic strength

Huafang Ni; David Hunkeler

1997-01-01

134

Synthesis and pharmacokinetic profile of a quaternary ammonium derivative of chlorambucil, a potential anticancer drug for the chemotherapy of chondrosarcoma.  

PubMed

As a part of our targeting program based on the affinity of the quaternary ammonium moiety for cartilage, our objective was to develop more selective anticancer drugs towards chondrosarcoma that would concentrate in this malignant cartilaginous tissue and so improve the therapeutic index through a reduction of side effects. For this purpose we have synthesized and labeled with 14C a quaternary ammonium (QA) derivative of chlorambucil. Biological studies performed in rats showed that [14C]-CQA and [14C]-chlorambucil exhibited different pharmacokinetic profiles. The blood elimination of [14C]-CQA was faster than that of parent compound. [14C]-CQA was principally excreted by the fecal way. However, until 15 min after administration, levels of radioactivity were measured in cartilaginous tissues of rats given [14C]-CQA which was not the case for the rats which had received [14C]-chlorambucil. Although rates of radioactivity were quantified only during 15 min, these results prove that the functionalization of chlorambucil by a quaternary ammonium group allows the molecule to be carried selectively to cartilaginous tissues. PMID:14604663

Rapp, Maryse; Giraud, Isabelle; Maurizis, Jean Claude; Madelmont, Jean Claude

2003-11-17

135

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

136

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

137

Quaternary ammonium bromide surfactant adsorption on low-index surfaces of gold. 1. Au(111).  

PubMed

The coadsorption of the anionic and cationic components of a model quaternary ammonium bromide surfactant on Au(111) has been measured using the thermodynamics of an ideally polarized electrode. The results indicate that both bromide and trimethyloctylammonium (OTA(+)) ions are coadsorbed over a broad range of the electrical state of the gold surface. At negative polarizations, the Gibbs surface excess of the cationic surfactant is largely unperturbed by the presence of bromide ions in solution. However, when the Au(111) surface is weakly charged the existence of a low-coverage, gaslike phase of adsorbed halide induces an appreciable (~25%) enhancement of the interfacial concentration of the cationic surfactant ion. At more positive polarizations, the coadsorbed OTA(+)/Br(-) layer undergoes at least one phase transition which appears to be concomitant with the lifting of the Au(111) reconstruction and the formation of a densely packed bromide adlayer. In the absence of coadsorbed halide, the OTA(+) ions are completely desorbed from the Au(111) surface at the most positive electrode polarizations studied. However, with NaBr present in the electrolyte, a high surface excess of bromide species leads to the stabilization of adsorbed OTA(+) at such positive potentials (or equivalent charge densities). PMID:22375812

Vivek, J P; Burgess, Ian J

2012-03-20

138

Anti-biofilm Dentin Primer with Quaternary Ammonium and Silver Nanoparticles  

PubMed Central

Antibacterial bonding agents could combat recurrent caries at the tooth-composite margins. The objectives of this study were to develop novel antibacterial dentin primers containing quaternary ammonium dimethacrylate (QADM) and nanoparticles of silver (NAg), and to investigate the effects on dentin bond strength and dental plaque microcosm biofilms for the first time. Scotchbond Multi-Purpose (“SBMP”) bonding agent was used. QADM and NAg were incorporated into SBMP primer, yielding 4 primers: SBMP primer (control), control + 10% QADM (mass), control + 0.05% NAg, and control + 10% QADM + 0.05% NAg. Human saliva was collected to grow microcosm biofilms. The NAg particle size (mean ± SD; n = 100) was 2.7 ± 0.6 nm. Dentin shear bond strengths (n = 10) with human third molars were approximately 30 MPa for all groups (p > 0.1). QADM-NAg-containing primer increased the bacteria inhibition zone by 9-fold, compared with control primer (p < 0.05). QADM-NAg-containing primer reduced lactic acid production and colony-forming units of total micro-organisms, total streptococci, and mutans streptococci by an order of magnitude. In conclusion, novel QADM-NAg-containing primers were strongly antibacterial without compromising dentin bond strength, and hence are promising to inhibit biofilms and secondary caries. The processing method of incorporating QADM and NAg together into the same primer produced the strongest antibacterial effect, which could have a wide applicability to other bonding systems.

Cheng, L.; Zhang, K.; Melo, M.A.S.; Weir, M.D.; Zhou, X.; Xu, H.H.K.

2012-01-01

139

Anti-biofilm dentin primer with quaternary ammonium and silver nanoparticles.  

PubMed

Antibacterial bonding agents could combat recurrent caries at the tooth-composite margins. The objectives of this study were to develop novel antibacterial dentin primers containing quaternary ammonium dimethacrylate (QADM) and nanoparticles of silver (NAg), and to investigate the effects on dentin bond strength and dental plaque microcosm biofilms for the first time. Scotchbond Multi-Purpose ("SBMP") bonding agent was used. QADM and NAg were incorporated into SBMP primer, yielding 4 primers: SBMP primer (control), control + 10% QADM (mass), control + 0.05% NAg, and control + 10% QADM + 0.05% NAg. Human saliva was collected to grow microcosm biofilms. The NAg particle size (mean ± SD; n = 100) was 2.7 ± 0.6 nm. Dentin shear bond strengths (n = 10) with human third molars were approximately 30 MPa for all groups (p > 0.1). QADM-NAg-containing primer increased the bacteria inhibition zone by 9-fold, compared with control primer (p < 0.05). QADM-NAg-containing primer reduced lactic acid production and colony-forming units of total micro-organisms, total streptococci, and mutans streptococci by an order of magnitude. In conclusion, novel QADM-NAg-containing primers were strongly antibacterial without compromising dentin bond strength, and hence are promising to inhibit biofilms and secondary caries. The processing method of incorporating QADM and NAg together into the same primer produced the strongest antibacterial effect, which could have a wide applicability to other bonding systems. PMID:22492276

Cheng, L; Zhang, K; Melo, M A S; Weir, M D; Zhou, X; Xu, H H K

2012-06-01

140

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

2013-04-01

141

Structural and conformational properties of the quaternary ammonium ionic liquid N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium iodide  

NASA Astrophysics Data System (ADS)

We have used single-crystal X-ray structural analysis and Raman spectroscopy to study the crystalline structure and conformational properties of a quaternary ammonium ionic liquid, N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium iodide ([DEME][I]). At 296 K the crystal structure of [DEME][I] was determined to be monoclinic (P21/a, Z = 8) with a = 13.216 (5), b = 12.842 (3), c = 14.417 (6), ? = 104.10 (3)°, and V = 2373.1 (15) Å3. With results from X-ray diffraction measurements and density functional theory calculations, we have identified two folded forms: Gauche--Gauche--gauche--gauche--trans and Gauche+-Gauche+-gauche+-gauche+-trans conformers, having intramolecular attractive N+⋯O- interactions of [DEME]+ in the single-crystal state. In the liquid state, [DEME]+ exists in equilibrium between folded and (non-interacting) extended forms.

Tsuge, Shu; Uno, Kenjiro; Hanasaki, Tomonori; Takekiyo, Takahiro; Abe, Hiroshi; Yoshimura, Yukihiro

2014-02-01

142

Thiolated quaternary ammonium-chitosan conjugates for enhanced precorneal retention, transcorneal permeation and intraocular absorption of dexamethasone.  

PubMed

Previously, a quaternary ammonium (N(+))-chitosan (Ch) conjugate (N(+)(60)-Ch) characterized by short pendant chains, made of 1.7+/-0.1 adjacent diethyl-dimethylene-ammonium groups, substituted onto the primary amino group of the chitosan repeating units (degree of substitution, 59.2+/-4.5%) was used to synthesize a multifunctional non-cytotoxic thiomer (N(+)(60)-Ch-SH(5)), carrying 4.5+/-0.7% thiol-bearing 3-mercaptopropionamide besides quaternary ammonium groups. The present work was aimed at evaluating the potential of N(+)(60)-Ch-SH(5) and N(+)(60)-Ch as bioactive excipients for dexamethasone (DMS) eyedrops. The DMS permeability across excised rabbit cornea was enhanced over the control value by the thiomer and the parent polymer to about the same extent (3.8 vs. 4.1 times). The mean precorneal retention time and AUC in the aqueous of DMS instilled in rabbit eyes via eyedrops were enhanced by the thiomer (MRT=77.96+/-3.57 min, AUC=33.19+/-6.96 microg ml(-1) min) more than the parent polymer (MRT=65.74+/-4.91 min, AUC=21.48+/-3.81 microg ml(-1) min) over the control (MRT=5.07+/-0.25 min, AUC=6.25+/-0.65 microg ml(-1) min). The quaternary ammonium ions were responsible for both permeabilization of corneal epithelium and polymer adhesion to precorneal mucus, while the thiols increased the latter. This synergistic action is the basis of the higher thiomer bioactivity in vivo. A good ocular tolerability of the chitosan derivatives resulted from in vivo experiments. PMID:20171277

Zambito, Ylenia; Di Colo, Giacomo

2010-06-01

143

Thin-film microextraction coupled to LC-ESI-MS/MS for determination of quaternary ammonium compounds in water samples.  

PubMed

The dual nature of the quaternary ammonium compounds, having permanently charged hydrophilic quaternary ammonium heads and long-chain hydrophobic tails, makes the sample preparation step and analysis of these compounds challenging. A high-throughput method based on thin-film solid-phase microextraction (SPME) and liquid chromatography mass spectrometry was developed for simultaneous quantitative analysis of nine benzylic and aliphatic quaternary ammonium compounds. Chromatographic separation and detection of analytes were obtained in reverse-phase mode in 8 min using a triple quadrupole mass spectrometer. Hydrophilic lipophilic balance particle-coated blades were found to be the most suitable among the different coatings tested in terms of recoveries and carryover on the blades. For desorption solvents, 70/30, v/v (A/B) with 0.1 % formic acid (where A is 10 mM ammonium acetate in acetonitrile/water (95/5?, v/v) and B is 0.1 %? (v/v) formic acid in isopropyl alcohol) was shown to be the most efficient solvent for the desorption of the analytes from the SPME sorbent. The SPME method was optimised in terms of extraction, pH, and preconditioning, as well as extraction and desorption times. Optimum conditions were 45 min of extraction time and 15 min of desorption time, all with agitation. The extraction was found to be optimum in a range of pH 6.0 to 8.0, which is consistent with the natural pH of water samples. Wide linear dynamic ranges with the developed method were obtained for each compound, enabling the application of the method for a wide range of concentrations. The developed method was validated according to the Food and Drug Administration criteria. The proposed method is the first SPME-based approach describing the applicability of the high-throughput thin-film SPME in a 96-well system for analysis of such challenging compounds. PMID:24337184

Boyac?, Ezel; Sparham, Chris; Pawliszyn, Janusz

2014-01-01

144

Identification of quaternary ammonium compounds as potent inhibitors of hERG potassium channels  

PubMed Central

The human ether-a-go-go-related gene (hERG) channel, a member of a family of voltage-gated potassium (K+) channels, plays a critical role in the repolarization of the cardiac action potential. The reduction of hERG channel activity as a result of adverse drug effects or genetic mutations may cause QT interval prolongation and potentially lead to acquired long QT syndrome. Thus, screening for hERG channel activity is important in drug development. Cardiotoxicity associated with the inhibition of hERG channels by environmental chemicals is also a public health concern. To assess the inhibitory effects of environmental chemicals on hERG channel function, we screened the National Toxicology Program (NTP) collection of 1408 compounds by measuring thallium influx into cells through hERG channels. Seventeen compounds with hERG channel inhibition were identified with IC50 potencies ranging from 0.26 to 22 ?M. Twelve of these compounds were confirmed as hERG channel blockers in an automated whole cell patch clamp experiment. In addition, we investigated the structure-activity relationship of seven compounds belonging to the quaternary ammonium compound (QAC) series on hERG channel inhibition. Among four active QAC compounds, tetra-n-octylammonium bromide was the most potent with an IC50 value of 260 nM in the thallium influx assay and 80 nM in the patch clamp assay. The potency of this class of hERG channel inhibitors appears to depend on the number and length of their aliphatic side-chains surrounding the charged nitrogen. Profiling environmental compound libraries for hERG channel inhibition provides information useful in prioritizing these compounds for cardiotoxicity assessment in vivo.

Xia, Menghang; Shahane, Sampada; Huang, Ruili; Titus, Steven A.; Shum, Enoch; Zhao, Yong; Southall, Noel; Zheng, Wei; Witt, Kristine L.; Tice, Raymond R.; Austin, Christopher P.

2011-01-01

145

Antibacterial amorphous calcium phosphate nanocomposites with a quaternary ammonium dimethacrylate and silver nanoparticles  

PubMed Central

Objectives Calcium and phosphate ion-releasing resin composites are promising for remineralization. However, there has been no report on incorporating antibacterial agents to these composites. The objective of this study was to develop antibacterial and mechanically-strong nanocomposites incorporating a quaternary ammonium dimethacrylate (QADM), nanoparticles of silver (NAg), and nanoparticles of amorphous calcium phosphate (NACP). Methods The QADM, bis(2-methacryloyloxyethyl) dimethylammonium bromide (ionic dimethacrylate-1), was synthesized from 2-(N,N-dimethylamino)ethyl methacrylate and 2-bromoethyl methacrylate. Ng was synthesized by dissolving Ag 2-ethylhexanoate salt in 2-(tertbutylamino)ethyl methacrylate. Mechanical properties were measured in three-point flexure with bars of 2×2×25 mm (n = 6). Composite disks (diameter = 9 mm, thickness = 2 mm) were inoculated with Streptococcus mutans. The metabolic activity and lactic acid production of biofilms were measured (n = 6). Two commercial composites were used as controls. Results Flexural strength and elastic modulus of NACP+QADM, NACP+NAg, and NACP+QADM+NAg matched those of commercial composites with no antibacterial property (p > 0.1). The NACP+QADM+NAg composite decreased the titer counts of adherent S. mutans biofilms by an order of magnitude, compared to the commercial composites (p < 0.05). The metabolic activity and lactic acid production of biofilms on NACP+QADM+NAg composite were much less than those on commercial composites (p < 0.05). Combining QADM and NAg rendered the nanocomposite more strongly antibacterial than either agent alone (p < 0.05). Significance QADM and NAg were incorporated into calcium phosphate composite for the first time. NACP+QADM+NAg was strongly-antibacterial and greatly reduced the titer counts, metabolic activity, and acid production of S. mutans biofilms, while possessing mechanical properties similar to commercial composites. These nanocomposites are promising to have the double benefits of remineralization and antibacterial capabilities to inhibit dental caries.

Cheng, Lei; Weir, Michael D.; Xu, Hockin H. K.; Antonucci, Joseph M.; Kraigsley, Alison M.; Lin, Nancy J.; Lin-Gibson, Sheng; Zhou, Xuedong

2012-01-01

146

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

2008-01-24

147

Mapping peptide thiol accessibility in membranes using a quaternary ammonium isotope-coded mass tag (ICMT).  

PubMed

The plasma membrane contains a diverse array of proteins, including receptors, channels, and signaling complexes, that serve as decision-making centers. Investigation of membrane protein topology is important for understanding the function of these types of protein. Here, we report a method to determine protein topology in the membrane that utilizes labeling of cysteine with isotope-coded mass tags. The mass tags contain a thiol reactive moiety, linker, and a quaternary ammonium group to aid ionization in the mass spectrometer and were synthesized in both light and heavy (deuterated) forms. The probes were found to be membrane impermeable when applied to lipid vesicles. To assess the utility of the probes for mapping peptide thiol topology, we employed a two-step labeling procedure. Vesicles containing ?-helical transmembrane peptides were labeled with heavy (or light) probe, solubilized by detergent, and then labeled by an excess of the complementary probe. Peptide for which the cysteine was oriented in the center of the lipid bilayer was not labeled until the lipid vesicles were lysed with detergent, consistent with the membrane impermeability of the probes and reduced ionization of the thiol in the hydrophobic membrane. Peptide for which the cysteine was positioned in the headgroup zone of the lipid bilayer was labeled rapidly. Peptide for which the cysteine was positioned below the headgroup abutting the hydrocarbon region was labeled at a reduced rate compared to the fully accessible cysteine. Moreover, the effect of lipid bilayer structure on the kinetics of peptide and lipid flipping in the bilayer was readily measured with our two-step labeling method. The small sample size required, the ease and rapidity of sample preparation, and the amenability of MALDI-TOF mass spectral analysis to the presence of lipids will enable future facile investigation of membrane proteins in a cellular context. PMID:23725486

Su, Chiao-Yung; London, Erwin; Sampson, Nicole S

2013-07-17

148

Cyclic quaternary ammonium ionic liquids with perfluoroalkyltrifluoroborates: synthesis, characterization, and properties.  

PubMed

New cyclic quaternary ammonium salts, composed of N-alkyl(alkyl ether)-N-methylpyrrolidinium, -oxazolidinium, -piperidinium, or -morpholinium cations (alkyl = nC4H9, alkyl ether = CH3OCH2, CH3OCH2CH2) and a perfluoroalkyltrifluoroborate anion ([R(F)BF3]-, R(F) = CF3, C2F5, nC3F7, nC4F9), were synthesized and characterized. Most of these salts are liquids at room temperature. The key properties of these salts--phase transitions, thermal stability, density, viscosity, conductivity, and electrochemical windows--were measured and compared to those of their corresponding [BF4]- and [(CF3SO2)2N]- salts. The structural effect on all the above properties was intensively studied in terms of the identity of the cation and anion, variation of the side chain in the cation (i.e., alkyl versus alkyl ether), and change in the length of the perfluoroalkyl group (R(F)) in the [R(F)BF3]- ion. The reduction of Li+ ions and reoxidation of Li metal took place in pure N-butyl-N-methylpyrrolidinium pentafluoroethyltrifluoroborate as the supporting electrolyte. Such comprehensive studies enhance the knowledge necessary to design and optimize ionic liquids for many applications, including electrolytes. Some of these new salts show desirable properties, including low melting points, high thermal stabilities, low viscosities, high conductivities, and wide electrochemical windows, and may thus be potential candidates for use as electrolytes in high-energy storage devices. In addition, many salts are ionic plastic crystals. PMID:16389616

Zhou, Zhi-Bin; Matsumoto, Hajime; Tatsumi, Kuniaki

2006-03-01

149

Molecular dynamics simulation of secondary sorption behavior of montmorillonite modified by single chain quaternary ammonium cations.  

PubMed

Organoclays synthesized from single chain quaternary ammonium cations (QAC) ((CH(3))(3)NR(+)) exhibit different mechanisms for the sorption of nonpolar organic compounds as the length of the carbon chain is increased. The interaction between a nonpolar sorbate and an organoclay intercalated with small QACs has been demonstrated to be surface adsorption, while partitioning is the dominant mechanism in clays intercalated with long chain surfactants. This study presents the results of a molecular dynamics (MD) simulation performed to examine the sorption mechanisms of benzene in the interlayer of three organoclays with chain lengths ranging from 1 to 16 carbons: tetramethylammonium (TMA) clay; decyltrimethylammonium (DTMA) clay; and hexadecyltrimethylammonium (HDTMA) clay. The basis of the overall simulation was a combined force field of ClayFF and CVFF. In the simulations, organic cations were intercalated and benzene molecules were introduced to the interlayer, followed by whole system NPT and NVT time integration. Trajectories of all the species were recorded after the system reached equilibrium and subsequently analyzed. Simulation results confirmed that the arrangement of the surfactants controlled the sorption mechanism of organoclays. Benzene molecules were observed to interact directly with the clay surface in the presence of TMA cations, but tended to interact with the aliphatic chain of the HDTMA cation in the interlayer. The simulation provided insight into the nature of the adsorption/partitioning mechanisms in organoclays, and explained experimental observations of decreased versus increased uptake capacities as a function of increasing total organic carbon (TOC) for TMA clay and HDTMA clay, respectively. The transition of sorption mechanisms was also quantified with simulation of DTMA clay, with a chain length between that of TMA and HDTMA. Furthermore, this study suggested that at the molecular level, the controlling factor for the ultimate sorption capacity is available surface sites in the case of TMA clay, and density of aliphatic chains within the interlayer space for HDTMA clay. PMID:22364194

Zhao, Qian; Burns, Susan E

2012-04-01

150

Asymmetric phase-transfer catalysis with homo- and heterochiral quaternary ammonium salts: a theoretical study.  

PubMed

A thorough theoretical study of phase-transfer quaternary ammonium catalysts designed by the Maruoka group has been performed in an attempt to gain better understanding of the properties and catalytic behavior of the homo- and heterochiral forms of these systems. The conformationally flexible analogue is found to easily undergo interconversion from the homo- to the heterochiral form driven by the higher thermodynamic stability of the heterochiral isomer and resulting in alternation in catalytic behavior. Theoretical calculations of (1)H NMR spectra of the two isomers for different model systems are in good agreement with the experimental data, allowing us to conclude that the upfield shift of signals for the benzylic protons in the heterochiral form could be explained by an increase in the shielding effect of the aromatic parts of the system around these protons due to the conformational changes. By applying the automated transition state (TS) search procedure for the alkylation of glycine derivatives catalyzed by the homo-/heterochiral form of a conformationally rigid analogue, we were able to locate more than 40 configurations of the TS structures. In brief, the homochiral form was theoretically confirmed to catalyze the formation of the predominant R-product, while for the heterochiral form the catalytic activity is found to depend on two factors: (i) formation of a tight ion pair between the catalyst and the glycine derivative, which results in a decrease in the reaction rate, in agreement with the experimental data, and formation of only the R-product, and (ii) the possibility that the reaction occurs without the initial formation of the ion pair or after its dissociation, in which case the formation of an S-product is predominant. The combined effects of both factors would explain the lower reaction rate and the poor enantioselectivity observed experimentally for the heterochiral form. PMID:24720781

Petrova, Galina P; Li, Hai-Bei; Maruoka, Keiji; Morokuma, Keiji

2014-05-15

151

Mapping peptide thiol accessibility in membranes using a quaternary ammonium isotope-coded mass tag (ICMT)  

PubMed Central

The plasma membrane contains a diverse array of proteins, including receptors, channels, and signaling complexes, that serve as decision-making centers. Investigation of membrane protein topology is important for understanding the function of these types of protein. Here, we report a method to determine protein topology in the membrane that utilizes labeling of cysteine with isotope-coded mass tags. The mass tags contain a thiol reactive moiety, linker, and a quaternary ammonium group to aid ionization in the mass spectrometer and were synthesizes as both light and heavy (deuterated) forms. The probes were found to be membrane impermeable when applied to lipid vesicles. To assess the utility of the probes for mapping peptide thiol topology, we employed a two-step labeling procedure. Vesicles containing ?-helical transmembrane peptides were labeled with heavy (or light) probe, solubilized by detergent, and then labeled by an excess of the complementary probe. Peptide for which the cysteine was oriented in the center of the lipid bilayer was not labeled until the lipid vesicles were lysed with detergent, consistent with the membrane impermeability of the probes and reduced ionization of the thiol in the hydrophobic membrane. Peptide for which the cysteine was positioned in the head group zone of the lipid bilayer was labeled rapidly. Peptide for which the cysteine was positioned below the head group abutting the hydrocarbon region was labeled at a reduced rate compared to the fully accessible cysteine. Moreover, the effect of lipid bilayer structure on the kinetics of peptide and lipid flipping in the bilayer was readily measured with our two-step labeling method. The small sample size required, the ease and rapidity of sample preparation, and the amenability of MALDI-TOF mass spectral to analysis in the presence of lipids will enable future facile investigation of membrane proteins in a cellular context.

Su, Chiao-Yung; London, Erwin; Sampson, Nicole S.

2013-01-01

152

Radiation Stability of Benzyl Tributyl Ammonium Chloride towards Technetium-99 Extraction - 13016  

SciTech Connect

A closed nuclear fuel cycle combining new separation technologies along with generation III and generation IV reactors is a promising way to achieve a sustainable energy supply. But it is important to keep in mind that future recycling processes of used nuclear fuel (UNF) must minimize wastes, improve partitioning processes, and integrate waste considerations into processes. New separation processes are being developed worldwide to complement the actual industrialized PUREX process which selectively separates U(VI) and Pu(IV) from the raffinate. As an example, the UREX process has been developed in the United States to co-extract hexavalent uranium (U) and hepta-valent technetium (Tc) by tri-n-butyl phosphate (TBP). Tc-99 is recognized to be one of the most abundant, long-lived radio-toxic isotopes in UNF (half-life, t{sub 1/2} = 2.13 x 10{sup 5} years), and as such, is targeted in UNF separation strategies for isolation and encapsulation in solid waste-forms for final disposal in a nuclear waste repository. Immobilization of Tc-99 by a durable solid waste-form is a challenge, and its fate in new advanced technology processes is of importance. It is essential to be able to quantify and locate 1) its occurrence in any new developed flowsheets, 2) its chemical form in the individual phases of a process, 3) its potential quantitative transfer in any waste streams, and consequently, 4) its quantitative separation for either potential transmutation to Ru-100 or isolation and encapsulation in solid waste-forms for ultimate disposal. In addition, as a result of an U(VI)-Tc(VII) co-extraction in a UREX-based process, Tc(VII) could be found in low level waste (LLW) streams. There is a need for the development of new extraction systems that would selectively extract Tc-99 from LLW streams and concentrate it for feed into high level waste (HLW) for either Tc-99 immobilization in metallic waste-forms (Tc-Zr alloys), and/or borosilicate-based waste glass. Studies have been launched to investigate the suitability of new macro-compounds such as crown-ethers, aza-crown ethers, quaternary ammonium salts, and resorcin-arenes for the selective extraction of Tc-99 from nitric acid solutions. The selectivity of the ligand is important in evaluating potential separation processes and also the radiation stability of the molecule is essential for minimization of waste and radiolysis products. In this paper, we are reporting the extraction of TcO{sub 4}{sup -} by benzyl tributyl ammonium chloride (BTBA). Experimental efforts were focused on determining the best extraction conditions by varying the ligand's matrix conditions and concentration, as well as varying the organic phase composition (i.e. diluent variation). Furthermore, the ligand has been investigated for radiation stability. The ?-irradiation was performed on the neat organic phases containing the ligand at different absorbed doses to a maximum of 200 kGy using an external Co-60 source. Post-irradiation solvent extraction measurements will be discussed. (authors)

Paviet-Hartmann, Patricia; Horkley, Jared; Campbell, Keri [Idaho National Laboratory, 2525 Fremont Street, Idaho Falls, ID 83402 (United States)] [Idaho National Laboratory, 2525 Fremont Street, Idaho Falls, ID 83402 (United States); Roman, Audrey [University of Nevada - Las Vegas, Harry Reid Center, 4505 S. Maryland Pkwy, Box 4009, Las Vegas, NV 89154-4009 (United States)] [University of Nevada - Las Vegas, Harry Reid Center, 4505 S. Maryland Pkwy, Box 4009, Las Vegas, NV 89154-4009 (United States); Nunez, Ana; Espartero, Amparo [CIEMAT, Avda Complutense, 40, 28040- Madrid (Spain)] [CIEMAT, Avda Complutense, 40, 28040- Madrid (Spain)

2013-07-01

153

Solubility of hydrogen sulfide in aqueous solutions of the single salts sodium sulfate, ammonium sulfate, sodium chloride, and ammonium chloride at temperatures from 313 to 393 K and total pressures up to 10 MPa  

Microsoft Academic Search

New experimental results for the solubility of hydrogen sulfide in aqueous solutions of the single salts sodium sulfate, ammonium sulfate, sodium chloride, and ammonium chloride at temperatures from 313 to 393 K and total pressures up to 10 MPa are reported. As in the salt-free system, a second-hydrogen sulfide-rich--liquid phase is observed at high hydrogen sulfide concentrations. A model to

Jianzhong Xia; A. P. S. Kamps; Bernd Rumpf; Gerd Maurer

2000-01-01

154

Solubility of hydrogen sulfide in aqueous solutions of the single salts sodium sulfate, ammonium sulfate, sodium chloride, and ammonium chloride at temperatures from 313 to 393 K and total pressures up to 10 MPa  

SciTech Connect

New experimental results for the solubility of hydrogen sulfide in aqueous solutions of the single salts sodium sulfate, ammonium sulfate, sodium chloride, and ammonium chloride at temperatures from 313 to 393 K and total pressures up to 10 MPa are reported. As in the salt-free system, a second-hydrogen sulfide-rich--liquid phase is observed at high hydrogen sulfide concentrations. A model to describe the phase equilibrium is presented. Calculations are compared to the new experimental data.

Xia, J.; Kamps, A.P.S.; Rumpf, B.; Maurer, G.

2000-04-01

155

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

2008-03-01

156

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

2009-08-01

157

21 CFR 878.4015 - Wound dressing with poly (diallyl dimethyl ammonium chloride) (pDADMAC) additive.  

Code of Federal Regulations, 2013 CFR

...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4015 Wound dressing with poly (diallyl dimethyl ammonium chloride) (pDADMAC)...

2013-04-01

158

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

159

Aerogels from quaternary ammonium-functionalized cellulose nanofibers for rapid removal of Cr(VI) from water.  

PubMed

An efficient heavy metal adsorbent from quaternary ammonium-functionalized cellulose nanofiber aerogels was successfully developed. The highly porous aerogel could well retain its large specific surface area, which allowed rapid and effective removal of Cr(VI) from contaminated water. The aerogel adsorbent became mechanically robust after chemical crosslinking. It could be easily separated from water after adsorption without complicated centrifugation or filtration process. With only 1g of aerogel, more than 99% of Cr(VI) in 1L of 1mg/L solution could be removed in 50min. Besides, the aerogel also exhibited excellent reusability. PMID:25037403

He, Xu; Cheng, Long; Wang, Yaru; Zhao, Jiangqi; Zhang, Wei; Lu, Canhui

2014-10-13

160

Process of inhibiting scale formation in aqueous systems using quaternary ammonium salts of. cap alpha. -1,4-thiazine  

SciTech Connect

Quaternary ammonium salts of ..cap alpha..-1,4-thiazine alkanephosphonic acids are described which inhibit scale formation in aqueous systems. The compounds also can be used in formation of acid corrosion inhibitors, as sequestering agents, and as microbiocides. These compounds are prepared by reacting an ..cap alpha..-1,4-thiazine alkanephosphonic acid compound with an alkylating agent in a suitable polar solvent or a mixture of polar solvents. Examples of solvents are water, mixtures of water and lower alcohols, lower alcohols, dimethyl formamide, dimethyl sulfoxide, and hexamethyulphosphorotrimide. 10 claims.

Quinlan, P.M.

1982-04-06

161

Improvement of the adsorption of quaternary ammonium on polypropylene affinity membrane through the control of its surface properties.  

PubMed

Polypropylene fiber meshes were plasma-treated in order to attach new chemical functions corresponding to acidic or basic groups without altering the roughness of such thin material. An almost complete wettability of these plasma-treated materials is obtained. Because of the plasma-grafting of acid or amino moieties, such surface treatment allows increasing the adsorption rate of quaternary ammonium molecule like Aliquat 336. This increase was explained by specific interactions of ammonium head of the Aliquat 336 and hydrophilic group of plasma-treated PP, followed by the adsorption of a further layer of Aliquat 336 through hydrophobic interactions of its hydrocarbon chain. These interactions between the carrier and the polymeric surface were characterized leading to physisorption mechanism. Such new material could be applied to the extraction process since no evidence of aging was given. PMID:24411392

Hachache, Naima; Bal, Youcef; Debarnot, Dominique; Poncin-Epaillard, Fabienne

2014-02-01

162

Quaternary ammonium block of mutant Na+ channels lacking inactivation: features of a transition-intermediate mechanism.  

PubMed

1. The quaternary ammonium (QA) lidocaine derivative QX-314 (2-(triethylamino)-N-(2,6-dimethylphenyl)-acetamide) induces internal pore blockade of single cardiac Na+ channels enzymatically modified (papain) to eliminate fast inactivation. The mechanism involves dual, interacting blocking modes (rapid and discrete) with binding domains deep in the pore from the cytoplasmic mouth, and where the rapid blocked configuration serves as a transition-intermediate for the development of discrete block. The primary goals of this study were to test for this mechanism in a recombinant Na+ channel genetically engineered to selectively lack fast inactivation, and if present, to explore the underlying structural features. 2. Fast inactivation was removed in rat skeletal muscle mu1 Na+ channels (RSkM1) with an IFM-QQQ mutation in the cytoplasmic III-IV interdomain (QQQ). QQQ was expressed in Xenopus oocytes and single-channel activity was studied in cell-free, inside-out membrane patches. Application of QX-314 (QX, 0-4 mM) to the cytoplasmic membrane surface caused two distinct modalities of single-channel blockade: reduction of unitary current and interruptions of current lasting tens of milliseconds. These are consistent with rapid and discrete pore block, respectively. The voltage and concentration dependence of block indicates that the modes interact and have binding sites that share a deep location in the pore, at approximately 65 % of the membrane electric field in from the cytoplasmic mouth. 3. Mutation of phenylalanine (F1579) in domain IV-S6, critical in local anaesthetic block, to alanine in QQQ (QQQ-F1579A) disabled discrete block but notably failed to alter rapid block, single-channel gating and slope conductance. 4. Amplitude distribution analysis was applied to long bursts (> 50 ms) of QQQ-F1579A activity to investigate the kinetics of rapid block. Computed rapid blocking and unblocking rate constants are 42 000 +/- 18 000 m-1 ms-1 and 82 +/- 22 ms-1, respectively (n = 3, -20 mV). 5. The results support a general transition-intermediate mechanism that governs internal QX and local anaesthetic pore block of voltage-gated Na+ channels and provide insight into underlying structural features. PMID:11080254

Kimbrough, J T; Gingrich, K J

2000-11-15

163

Metabolites and dead-end products from the microbial oxidation of quaternary ammonium alcohols  

Microsoft Academic Search

Methyl-triethanol-ammonium originates from the hydrolysis of the parent esterquat surfactant, which is used as softener in fabric care. The initial steps of the catabolism were investigated in cell-free extracts of the bacterial strain MM 1 able to grow with methyl-triethanol-ammonium as sole source of carbon, energy and nitrogen. The initial degradation of methyl-triethanol-ammonium is an enzymatically catalyzed reaction, located in

Andres Kaech; Martina Hofer; Daniel Rentsch; Christian Schnider; Thomas Egli

2005-01-01

164

Accelerated OH(-) Transport in Activated Carbon Air Cathode by Modification of Quaternary Ammonium for Microbial Fuel Cells.  

PubMed

Activated carbon (AC) is a promising catalyst for the air cathode of microbial fuel cells (MFCs) because of its high performance and low cost. To increase the performance of AC air cathodes, the acceleration of OH(-) transport is one of the most important methods, but it has not been widely investigated. Here we added quaternary ammonium to ACs by in situ anchoring of a quaternary ammonium/epoxide-reacting compound (QAE) or ex situ mixing with anion exchange resins in order to modify ACs from not only the external surface but also inside the pores. In 50 mM phosphate buffer solution (PBS), the in situ anchoring of QAE was a more effective way to increase the power. The highest power density of 2781 ± 36 mW/m(2), which is 10% higher than that of the control, was obtained using QAE-anchored AC cathodes. When the medium was switched to an unbuffered NaCl solution, the increase in maximum power density (885 ± 25 mW/m(2)) was in accordance with the anion exchange capacity (0.219 mmol/g). The highest power density of the anion exchange resin-mixed air cathode was 51% higher than that of the control, indicating that anion exchange is urgently needed in real wastewaters. Excess anchoring of QAE blocked both the mesopores and micropores, causing the power output to be inhibited. PMID:24597673

Wang, Xin; Feng, Cuijuan; Ding, Ning; Zhang, Qingrui; Li, Nan; Li, Xiaojing; Zhang, Yueyong; Zhou, Qixing

2014-04-01

165

Effect of quaternary ammonium cations on dye sorption to fly ash from aqueous media  

Microsoft Academic Search

The efficacy of the surface modification of fly ash by quarternary ammonium cations in the removal of dyes from aqueous solution is demonstrated. A series of organo-fly ash materials were synthesized by treating fly ash with quarternary ammonium cations such as tetraethylammonium, hexadecyltrimethylammonium, and benzyldimethyltetradecylammonium (TEA, HDTMA, and BDTDA). Two types of dyes were used for the investigation, disperse and

Shashwat S. Banerjee; Milind V. Joshi; Radha V. Jayaram

2006-01-01

166

Radiation-induced grafting of vinyl benzyl trimethyl ammonium chloride onto nylon-6 fabric  

NASA Astrophysics Data System (ADS)

Vinyl benzyl trimethyl ammonium chloride (VBTAC) was grafted onto nylon-6 fabric in the presence of 2- hydroxy ethyl methacrylate (HEMA) by the simultaneous irradiation method in the presence of air with 60Co ?-radiations. An increase in grafting was observed with increasing dose. Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) confirmed the grafting of VBTAC. Morphological changes after grafting were confirmed by scanning electron microscopy (SEM). The X-ray diffraction (XRD) pattern showed changes in crystallinity on grafting. The initial studies carried out with grafted nylon fabric showed behavioural changes in the burning properties.

Kolhe, Shailesh M.; Kumar, Ashok

2007-05-01

167

Charge–discharge and high temperature reaction of LiCoO 2 in ionic liquid electrolytes based on cyano-substituted quaternary ammonium cation  

Microsoft Academic Search

The charge–discharge performance of LiCoO2 positive electrode was observed in a mixed electrolyte system consisting of two ionic liquids: cyano-substituted quaternary ammonium bis(trifluoromethane)sulfoneimide (TFSI) and a same-anion salt of 1-ethyl-3-methyl imidazolium (EMI). The positive electrode exhibited a discharge capacity rather close to the theoretical one when N,N,N,N-cyanoethyl trimethyl ammonium salt was applied. Differential scanning calorimetry (DSC) studies revealed that these

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

2006-01-01

168

Metabolites and dead-end products from the microbial oxidation of quaternary ammonium alcohols.  

PubMed

Methyl-triethanol-ammonium originates from the hydrolysis of the parent esterquat surfactant, which is used as softener in fabric care. The initial steps of the catabolism were investigated in cell-free extracts of the bacterial strain MM 1 able to grow with methyl-triethanol-ammonium as sole source of carbon, energy and nitrogen. The initial degradation of methyl-triethanol-ammonium is an enzymatically catalyzed reaction, located in the particulate fraction of strain MM 1. The oxygen dependent reaction occurred also in presence of phenazine methosulfate as an alternative electron acceptor. As soon as one ethanol group of methyl-triethanol-ammonium was oxidized to the aldehyde, cyclic hemiacetals were formed by intramolecular cyclization. The third ethanol group of methyl-triethanol-ammonium was oxidized to the aldehyde and the carboxylic acid sequentially. The structurally related compounds dimethyl-diethanol-ammonium and choline were oxidized as well, whereas (+/-)-2,3-dihydroxypropyl-trimethyl-ammonium was not converted at all. The structures of the metabolites were established by 1D and 2D 1H, 13C and 14N NMR spectroscopy and by capillary electrophoresis mass spectrometry. PMID:15865159

Kaech, Andres; Hofer, Martina; Rentsch, Daniel; Schnider, Christian; Egli, Thomas

2005-10-01

169

Specific variations of fatty acid composition of Pseudomonas aeruginosa ATCC 15442 induced by quaternary ammonium compounds and relation with resistance to bactericidal activity.  

PubMed

The role of membrane fatty acid composition in the resistance of Pseudomonas aeruginosa ATCC 15442 to the bactericidal activity of Quaternary Ammonium Compounds (QACs) was investigated. The strain was grown in a medium with increasing concentrations of a QAC, benzyldimethyltetradecylammonium chloride (C14) and two non-QACs, sodium dichloroisocyanurate and tri-sodium phosphate. In the presence of C14 only, the strain was able to grow in concentrations higher than the minimal inhibitory concentration. As the strain adapted to C14, resistance to bactericidal activity of the same biocide increased. For the non-QACs, no change was noted when cells were grown in the presence of biocides. The C14-adapted cells showed variations in membrane fatty acid composition. A hierarchical clustering analysis was used to compare all fatty acid compositions of cultures in the presence, or not, of the three biocides used here and another QAC studied previously. The clusters obtained underlined specific variations of membrane fatty acids in response to the presence of QACs. Furthermore, with a simple linear regression analysis, a relationship was shown between the membrane fatty acids and the resistance developed by the strain against the bactericidal activity of C14. PMID:10594715

Guérin-Méchin, L; Dubois-Brissonnet, F; Heyd, B; Leveau, J Y

1999-11-01

170

Influence of pH and diluent on the ion-pair solvent extraction of aromatic carboxylic acids using quaternary ammonium salts  

SciTech Connect

The influence of pH and diluent on the ion-pair solvent extraction of benzene polycarboxylic acids have been investigated for the separation of the coal oxidation products, which are formed by the treatment with alkaline solutions at high temperatures. Although the extent of the solvent extraction of benzoic acid (1BE) with a quaternary ammonium reagent (tri-n-octylmethylammonium chloride) into chloroform and benzene did not change at a very acidic and alkaline solutions, those of 1,2-benzenedicarboxylic acid (12BE) and trimellitic acid (124BE) somewhat decreased at very low pH and very high pH. The magnitudes of the equilibrium constants (K{sub ex}) of 1BE using a different diluent decreased in the order benzene {gt} carbontetrachloride {gt} 1,2-dichloroethane {gt} cyclohexane {gt} hexane {gt} chloroform {gt} 1-octanol and those of 12BE decreased in the order benzene {gt} cyclohexane {gt} carbontetrachloride {gt} hexane {gt} 1,2-dichloroethane {gt} chloroform. The inspection of the correlation between the values of K{sub ex} and several parameters of the diluent implies that the magnitude of K{sub ex} can be described by using the dielectric constant and the solubility parameter of diluent.

Kawamura, K.; Takahashi, K.; Okuwaki, A. [Tohoku University, Miyagi (Japan). Graduate School for Environmental Studies

2006-07-01

171

Receptor model source attributions for Utah's Salt Lake City airshed and the impacts of wintertime secondary ammonium nitrate and ammonium chloride aerosol.  

PubMed

Communities along Utah's Wasatch Front are currently developing strategies to reduce daily average PM2.5 levels to below National Ambient Air Quality Standards during wintertime persistent stable atmospheric conditions, or cold-air pools. Speciated PM2.5 data from the Wasatch Front airshed indicate that wintertime exceedances of the PM2.5 standard are mainly driven by high levels of ammonium nitrate. Stable wintertime conditions foster the formation of ammonium nitrate aerosol when sufficient sources of NO(x), ammonia, and oxidative capacity exist. However this work demonstrates that secondary ammonium chloride aerosol can also be a significant source of secondary wintertime PM2.5 if sufficient sources of atmospheric chlorine exist. Two factor analysis techniques, positive matrix factorization (PMF) and Unmix, were used to identify contributors to PM2.5 at three monitoring stations along Utah's Wasatch Front: Bountiful, Lindon, and Salt Lake City. The monitoring data included chemically speciated PM2.5 data for 227, 227, and 429 days at each location, respectively, during the period from May 2007 through May 2011. PMF identified 10-12 factors and Unmix identified 4-5 factors for each of the locations. The wintertime PMF and Unmix results showed large contributions from secondary PM2.5 when PM2.5 concentrations exceeded 20 microg/m3. PMF identified both ammonium nitrate and ammonium chloride aerosol as significant secondary contributors to PM2.5 (10-15% of total PM2.5 from ammonium chloride) during wintertime pollution episodes. Subsequent ion balance analysis of the monitoring data confirmed the presence of significant ammonium chloride aerosol on these highly polluted days at all three monitoring sites. The directly emitted primary PM2.5 portions of the source attribution results were further compared to county-level emissions inventories and showed generally good agreement for Salt Lake City and Lindon during wintertime except for wood smoke and fugitive dust, which have higher contributions in the receptor modeling results than in the emissions inventories. Implications: The study suggests that secondary ammonium chloride aerosol can be a significant source ofwintertime PM2.5 in an ammonia-rich environment, like the Wasatch Front airshed, if sufficient sources of atmospheric chlorine exist. During wintertime, cold-air-pool events, the source attribution results generally agree with the county emission inventories with the exception of wood smoke and cooking sources. At the Salt Lake City monitoring station, the estimated contributions from wood smoke and cooking are nearly double those of the corresponding inventory, suggesting that they are nearly as important as gasoline emissions. PMID:23786149

Kelly, Kerry E; Kotchenruther, Robert; Kuprov, Roman; Silcox, Geoffrey D

2013-05-01

172

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

173

Deliquescence and crystallization of ammonium sulfate-glutaric acid and sodium chloride-glutaric acid particles  

NASA Astrophysics Data System (ADS)

In the following, we report the deliquescence relative humidities (DRH) and crystallization relative humidities (CRH) of mixed inorganic-organic particles, specifically ammonium sulfate-glutaric acid and sodium chloride-glutaric acid particles. Knowledge of the DRH and CRH of mixed inorganic-organic particles is crucial for predicting the role of aerosol particles in the atmosphere. Our DRH results are in good agreement with previous measurements, but our CRH results are significantly lower than some of the previous measurements reported in the literature. Our studies show that the DRH and CRH of ammonium sulfate and sodium chloride only decreased slightly when the mole fraction of the acid was less than 0.4. If other organics in the atmosphere behave in a similar manner, then the DRH and CRH of mixed inorganic-organic atmospheric particles will only be slightly less than the DRH and CRH of pure inorganic particles when the organic mole fraction is less than 0.4. Our results also show that if the particles contain a significant amount of organics (mole fraction > 0.5) the crystallization relative humidity decreases significantly and the particles are more likely to remain in the liquid state. Further work is needed to determine if other organics species of atmospheric importance have a similar effect.

Pant, Atul; Fok, Abel; Parsons, Matthew T.; Mak, Jackson; Bertram, Allan K.

2004-06-01

174

New trimeric Cinchona alkaloid-based quaternary ammonium salts as efficient chiral phase transfer catalysts for enantioselective synthesis of ?-amino acids  

Microsoft Academic Search

New trimeric quaternary ammonium salts derived from cinchonine or cinchonidine bridging N,N?-bis(ethyl)-4-(methyl)-phenyl-amine moiety are used as a chiral phase transfer catalysts for the asymmetric alkylation of a N-(diphenylmethylene)glycine tert-butyl ester with very good chemical yield (up to 97%) and ee's (up to 98%).

Ayyanar Siva; Eagambaram Murugan

2006-01-01

175

Inverse-emulsion copolymerization of acrylamide and quaternary ammonium cationic monomers with block copolymeric surfactants: copolymer composition control using batch and semi-batch techniques  

Microsoft Academic Search

An experimental investigation of the inverse-emulsion copolymerization of acrylamide and quaternary ammonium cationic monomers (dimethylaminoethylacrylate, DMAEA and dimethylaminoethylmethacrylate, DMAEM) has been carried out using both a block copolymeric surfactant (HB246) whose hydrophilic moiety is polyethylene oxide and whose hydrophobic moiety is poly(12 hydroxy stearic acid) and sorbitan monoleate (SMO). Our results indicate that the choice of surfactant influences strongly the

José Hernández-Barajas; David J. Hunkeler

1997-01-01

176

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

177

Occurrence of quaternary ammonium compounds (QACs) and their application as a tracer for sewage derived pollution in urban estuarine sediments.  

PubMed

Particle reactive organic contaminants in estuarine sediments can lead to various environmental problems affecting ecosystem and public health. In this study, the occurrence and homologous distribution pattern of quaternary ammonium compounds (QACs) in the surficial sediments collected from the Pearl River Estuary (PRE), China were examined along with polychlorinated biphenyls (PCBs) and polybrominated diphenylethers (PBDEs). The composition pattern of the QACs was found to be uniform in most of the sediments analyzed throughout the PRE, and the average composition pattern was identical to that determined in the sewage sludge from Guangzhou, the biggest city in the PRE. Dialkyldimethylammonium compounds, the most abundant type of QACs, positively correlated to the total concentrations of PCBs and PBDEs in most of the sediments with similar composition patterns. Therefore, the QACs are proposed as potential tracers to evaluate the transport of sewage-derived pollution in estuarine environments. PMID:24270101

Li, Xiaolin; Luo, Xiaojun; Mai, Bixian; Liu, Jingqin; Chen, Li; Lin, Shanshan

2014-02-01

178

Quaternary ammonium-functionalized silica sorbents for the solid-phase extraction of aromatic amines under normal phase conditions.  

PubMed

Quaternary ammonium-functionalized silica materials were synthesized and applied for solid-phase extraction (SPE) of aromatic amines, which are classified as priority pollutants by US Environmental Protection Agency. Hexamethylenetetramine used for silica surface modification for the first time was employed as SPE sorbent under normal phase conditions. Hexaminium-functionalized silica demonstrated excellent extraction efficiencies for o-toluidine, 4-ethylaniline and quinoline (recoveries 101-107%), while for N,N-dimethylaniline and N-isopropylaniline recoveries were from low to moderate (14-46%). In addition, the suitability of 1-alkyl-3-(propyl-3-sulfonate) imidazolium-functionalized silica as SPE sorbent was tested under normal phase conditions. The recoveries achieved for the five aromatic amines ranged from 89 to 99%. The stability of the sorbent was evaluated during and after 150 extractions. Coefficients of variation between 4.5 and 10.2% proved a high stability of the synthesized sorbent. Elution was carried out using acetonitrile in the case of hexaminium-functionalized silica and water for 1-alkyl-3-(propyl-3-sulfonate) imidazolium-functionalized silica sorbent. After the extraction the analytes were separated and detected by liquid chromatography ultraviolet detection (LC-UV). The retention mechanism of the materials was primarily based on polar hydrogen bonding and ?-? interactions. Comparison made with activated silica proved the quaternary ammonium-functionalized materials to offer different selectivity and better extraction efficiencies for aromatic amines. Finally, 1-alkyl-3-(propyl-3-sulfonate) imidazolium-functionalized silica sorbent was successfully tested for the extraction of wastewater and soil samples. PMID:23473515

Vidal, Lorena; Robin, Orlane; Parshintsev, Jevgeni; Mikkola, Jyri-Pekka; Riekkola, Marja-Liisa

2013-04-12

179

A Systematic Investigation of Quaternary Ammonium Ions as Asymmetric Phase Transfer Catalysts. Application of Quantitative Structure Activity/Selectivity Relationships  

PubMed Central

While the synthetic utility of asymmetric phase transfer catalysis continues to expand, the number of proven catalyst types and design criteria remains limited. At the origin of this scarcity is a lack in understanding of how catalyst structural features affect the rate and enantioselectivity of phase transfer catalyzed reactions. Described in this paper is the development of quantitative structure-activity relationships (QSAR) and -selectivity relationships (QSSR) for the alkylation of a protected glycine imine with libraries of quaternary ammonium ion catalysts. Catalyst descriptors including ammonium ion accessibility, interfacial adsorption affinity, and partition coefficient were found to correlate meaningfully with catalyst activity. The physical nature of the descriptors was rationalized through differing contributions of the interfacial and extraction mechanisms to the reaction under study. The variation in the observed enantioselectivity was rationalized employing a comparative molecular field analysis (CoMFA) using both the steric and electrostatic fields of the catalysts. A qualitative analysis of the developed model reveals preferred regions for catalyst binding to afford both configurations of the alkylated product.

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

2011-01-01

180

Synthesis, characterization and thermal properties of new aromatic quaternary ammonium bromides: precursors for ionic liquids and complexation studies  

SciTech Connect

Series of new aromatic R{sub 2}R'{sub 2}N{sup +}Br{sup -} (R=benzyl, 4-methylbenzyl, 2-phenylethyl, 3-phenylpropyl; R'=ethyl, methyl, isopropyl) or RR'{sub 2}NH{sup +}Br{sup -}-type (R=benzyl, R'=isopropyl) quaternary ammonium bromides were prepared by using novel synthetic route in which a formamide (N,N-diethylformamide, N,N-dimethylformamide, N,N-diisopropylformamide) is treated with aralkyl halide in presence of a weak base. The compounds were characterized by {sup 1}H-NMR and {sup 13}C-NMR spectroscopy and mass spectrometry. Structures of the crystalline compounds were determined by X-ray single crystal diffraction, and in addition the powder diffraction method was used to study the structural similarities between the single crystal and microcrystalline bulk material. Three of the compounds crystallized in monoclinic, two in orthorhombic and one in triclinic crystal system, showing ion pairs, which are interconnected by weak hydrogen bonds and weak {pi}-{pi} interactions between the phenyl rings. Three of the compounds appeared as viscous oil or waxes. Finally, TG/DTA and DSC methods were used to analyze thermal properties of the prepared compounds. The lowest melting points were obtained for diethyldi-(2-phenylethyl)ammonium bromide (122.2{sup o}C) and for diethyldi-(3-phenylpropyl)-ammonium bromide (109.1{sup o}C). In general, decomposition of the compounds started at 170-190{sup o}C without identifiable cleavages, thus liquid ranges of 30-70{sup o}C were observed for some of the compounds.

Busi, Sara [Department of Chemistry, University of Jyvaeskylae, P.O. Box 35, 40014 Jyvaeskylae (Finland); Lahtinen, Manu [Department of Chemistry, University of Jyvaeskylae, P.O. Box 35, 40014 Jyvaeskylae (Finland)]. E-mail: makrla@cc.jyu.fi; Ropponen, Jarmo [Department of Chemistry, University of Jyvaeskylae, P.O. Box 35, 40014 Jyvaeskylae (Finland); Valkonen, Jussi [Department of Chemistry, University of Jyvaeskylae, P.O. Box 35, 40014 Jyvaeskylae (Finland); Rissanen, Kari [Department of Chemistry, University of Jyvaeskylae, P.O. Box 35, 40014 Jyvaeskylae (Finland)

2004-10-01

181

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

182

Ion-exchange sorption of quaternary ammonium bases on sulfo-resins of various structures  

Microsoft Academic Search

1.High selectivity of the polycondensation resins KU-5A and KU-1 with respect to the ion of a quarternary ammonium basetriethylbenzylammonium was detected.2.The coefficient of selectivity in the TEBA-Na system changes negligibly with increasing temperature: it decreases on the resins KU-6, Dowex 50×1, and KU-5A and increases on the resin KU-1.3.The coefficient of selectivity in the systems studied decreases sharply with increasing

G. V. Samsonov; B. V. Moskvichev

1967-01-01

183

Multicomponent reactions of ammonium thiocyanate, acyl chlorides, alkyl bromides, and enaminones: a facile one-pot synthesis of thiophenes.  

PubMed

An efficient synthesis of thiophene derivatives is described via one-pot reaction between ammonium thiocyanate, acyl chlorides, ?-halocarbonyls, and enaminones under solvent-free conditions at 65 °C. The mild reaction conditions and high yields of the products exhibit the good synthetic advantage of these methods. PMID:21695452

Hossaini, Zinatossadat; Rostami-Charati, Faramarz; Soltani, Samira; Mirzaei, Anwar; Berijani, Kayhaneh

2011-11-01

184

Determination of the Optimum Conditions for Leaching of Zinc Cathode Melting Furnace Slag in Ammonium Chloride Media  

NASA Astrophysics Data System (ADS)

This research is part of a continuing effort to leach zinc from zinc cathode melting furnace slags (ZCMFSs) to produce zinc oxide. The slag with an assay of 68.05 pct Zn was used in ammonium chloride leaching for zinc extraction. In this paper, the effects of influential factors on extraction efficiency of Zn from a ZCMFS were investigated. The Taguchi's method based on orthogonal array (OA) design has been used to arrange the experimental runs in order to maximize zinc extraction from a slag. The softwares named Excel and Design-Expert 7 have been used to design experiments and subsequent analysis. OA L 25 (55) consisting of five parameters, each with five levels, was employed to evaluate the effects of reaction time ( t = 10, 30, 50, 70, 90 minutes), reaction temperature [ T = 313, 323, 333, 343, 353 (40, 50, 60, 70, 80) K (°C)], pulp density ( S/ L = 20, 40, 60, 80, 100 g/L), stirring speed ( R = 300, 400, 500, 600, 700 rpm), and ammonium chloride concentration ( C = 10, 15, 20, 25, 30 pctwt), on zinc extraction percent. Statistical analysis, ANOVA, was also employed to determine the relationship between experimental conditions and yield levels. The results showed that the significant parameters affecting leaching of slag were ammonium chloride concentration and pulp density, and increasing pulp density reduced leaching efficiency of zinc. However, increasing ammonium chloride concentration promoted the extraction of zinc. The optimum conditions for this study were found to be t 4: 70 minutes, T 5: 353 K (80 °C), ( S/ L)2: 40 g/L, R 3: 500 rpm, and C 4: 25 pctwt. Under these conditions, the dissolution percentage of Zn in ammonium chloride media was 94.61 pct.

Behnajady, Bahram; Babaeidehkordi, Amin; Moghaddam, Javad

2014-04-01

185

Quaternary ammonium and phosphonium based ionic liquids: a comparison of common anions.  

PubMed

A series of ammonium-based ionic liquids and their phosphonium analogues have been investigated using X-ray Photoelectron Spectroscopy (XPS). A robust C 1s peak fitting model has been developed and described for the tetraalkylphosphonium and tetraalkylammonium families of ionic liquid, with comparisons made between the two series. Cation-anion interactions have been investigated to determine the impact of changing the cationic core from nitrogen to phosphorus upon the electronic environment of the anion. Comparisons between long and short chain cationic systems are also described. PMID:24942199

Blundell, Rebecca K; Licence, Peter

2014-08-01

186

Relationship between the resistance genes to quaternary ammonium compounds and antibiotic resistance in staphylococci isolated from surgical site infections  

PubMed Central

Background We aimed to investigate the prevalence of disinfectant resistance genes (qacA/qacB,qacC) and the aminoglycosides resistance genes [(aac(6?)aph(2?),aph(3?)-IIIa,ant(4?)-Ia)] in both S. aureus and coagulase-negative staphylococcal strains (CoNS) isolated from surgical site infections. Material/Methods Totally, 130 staphylococcal strains isolated from surgical site infections between January 2012 and February 2013 were included in the study. The PCR technique was employed to verify any presence of methicillin resistance gene (mecA), aminoglycoside resistance genes [(aac(6?)/aph (2?), aph(3)-III a ant (4?)-1a)], and disinfectant resistance genes (qacA/qacB,qacC) in staphylococci. Results MecA gene was determined in 58 (44.6%) of 130 staphylococcal isolates. A total of 28 (73.7%) of 38 S. aureus isolates were found to be positive for the mecA gene, and 4 (12.9%) of 31 isolates sensitive to amikacin were sensitive to methicillin. Eighteen (47.4%) of 38 amikacin-resistant S. aureus isolates were found to be positive for qacA/qacB genes and 11 (8.9%) of them were positive for qacC gene. Both mecA and qacA/qacB genes were found to be positive at the same time in 19 amikacin-resistant S. aureus strains. Seven (18.4%) S. aureus isolates were determined to be positive for qacA/qacB and qacC genes. Frequency of qacA/B genes was found to be 47.4% among amikacin-resistant S. aureus strains, while qacC gene was found to be 28.9% (p<0.05). The ratio of qacA/B and qacC genes in CoNS was found to be 37.9% and 20.7%, respectively (p<0.05). Conclusions Quaternary ammonium resistance genes were found to be positive at a remarkable ratio in the staphylococcal isolates from surgical wounds. Especially, the high rates of aminoglycosides and methicillin-resistance gene was remarkable in S. aureus isolates. Quaternary ammonium resistance genes were found to be positive.

Temiz, Muhyittin; Duran, Nizami; Duran, Gulay Gulbol; Ery?lmaz, Naciye; Jenedi, Kemal

2014-01-01

187

Preparation and characterisation of anion exchangers with dihydroxy-containing alkyl substitutes in the quaternary ammonium functional groups.  

PubMed

Novel poly(styrene-divinylbenzene) (PS-DVB) based anion exchangers having one and two (2,3-dihydroxypropyl) substitutes in the quaternary ammonium functional groups are prepared and characterised by ion chromatography (IC). The introduction of bulky and hydrophilic substitutes to the anion-exchange groups allows the elimination of non-ionic interactions between the polarisable anions and the aromatic rings from the matrix and the improvement of separation selectivity as compared with the traditional trimethylammonium (TMA) functionalised ion exchangers. The synthesis of the ion exchangers includes acylation of PS-DVB particles with acetic anhydride followed by reductive amination either with methylamine hydrochloride or dimethylamine and further alkylation with oxiranes under varied conditions. The ion exchange selectivity and separation efficiency of nine adsorbents having different structure of bonded groups, ion exchange capacity (9-98?equiv.g(-1)) or particle size is studied for model mixture of inorganic anions (F(-), Cl(-), NO2(-), Br(-), NO3(-), HPO4(2-) and SO4(2-)) using carbonate and hydroxide eluents. The adsorbents with more hydrophilic substitutes provided superior columns efficiencies and better peak symmetry as compared with analogues having hydrophobic functional groups. The calculated values of column efficiencies for polarisable NO3(-) and HPO4(2-) are 18,500 and 29,000N/m, respectively, for anion-exchanger, having N-methyl-N',N?-di-(2,3-dihydroxypropyl)ammonium groups which is significantly higher than 1800 and 12,000N/m obtained for these anions with anion exchanger bearing TMA functional groups. PMID:24309716

Zatirakha, A V; Smolenkov, A D; Pirogov, A V; Nesterenko, P N; Shpigun, O A

2014-01-01

188

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

Microsoft Academic Search

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

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

2009-01-01

189

Quaternary Ammonium Ionic Liquids as Bifunctional Catalysts for One-step Synthesis of Dimethyl Carbonate from Ethylene Oxide, Carbon Dioxide and Methanol  

Microsoft Academic Search

\\u000a Abstract  One kind of novel ionic liquids (ILs) with a tertiary amino moiety and a quaternary ammonium group were synthesized and identified\\u000a by FT-IR, 1H and 13C NMR. The elemental chemical state and basicity of ILs were determined by XPS and Hammett indicator method, respectively.\\u000a Then the catalytic performance of these bi-functional catalysts was investigated in one-step synthesis of dimethyl carbonate

Jian Li; Liguo Wang; Feng Shi; Shimin Liu; Yude He; Liujin Lu; Xiangyuan Ma; Youquan Deng

2011-01-01

190

Synthesis and in vitro evaluation of quaternary ammonium derivatives of chlorambucil and melphalan, anticancer drugs designed for the chemotherapy of chondrosarcoma.  

PubMed

To enhance affinity for malignant cartilaginous tumors (chondrosarcomas), quaternary ammonium (QA) conjugates of chlorambucil and melphalan were prepared by linking the QA moiety to nitrogen mustards via an amide bond. They exhibited closely similar and sometimes more favorable values than their parent compounds. In the cell lines tested, the two QA conjugates displayed appreciable cytotoxicity, the QA conjugate of chlorambucil even showing an enhanced efficiency against chondrosarcoma compared with chlorambucil. PMID:11985479

Giraud, Isabelle; Rapp, Maryse; Maurizis, Jean-Claude; Madelmont, Jean-Claude

2002-05-01

191

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

192

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

2013-03-01

193

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

194

Efficacies of Sodium Hypochlorite and Quaternary Ammonium Sanitizers for Reduction of Norovirus and Selected Bacteria during Ware-Washing Operations  

PubMed Central

Cross-contamination of ready-to-eat (RTE) foods with pathogens on contaminated tableware and food preparation utensils is an important factor associated with foodborne illnesses. To prevent this, restaurants and food service establishments are required to achieve a minimum microbial reduction of 5 logs from these surfaces. This study evaluated the sanitization efficacies of ware-washing protocols (manual and mechanical) used in restaurants to clean tableware items. Ceramic plates, drinking glasses and stainless steel forks were used as the food contact surfaces. These were contaminated with cream cheese and reduced-fat milk inoculated with murine norovirus (MNV-1), Escherichia coli K-12 and Listeria innocua. The sanitizing solutions tested were sodium hypochlorite (chlorine), quaternary ammonium (QAC) and tap water (control). During the study, the survivability and response to the experimental conditions of the bacterial species was compared with that of MNV-1. The results showed that current ware-washing protocols used to remove bacteria from tableware items were not sufficient to achieve a 5 log reduction in MNV-1 titer. After washing, a maximum of 3 log reduction in the virus were obtained. It was concluded that MNV-1 appeared to be more resistant to both the washing process and the sanitizers when compared with E. coli K-12 and L. innocua.

Feliciano, Lizanel; Li, Jianrong; Lee, Jaesung; Pascall, Melvin A.

2012-01-01

195

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

196

Quaternary ammonium compounds in urban estuarine sediment environments--a class of contaminants in need of increased attention?  

PubMed

The distributions of wastewater-derived quaternary ammonium compounds (QACs) were determined in surficial sediments (n = 47) collected from the urbanized lower Hudson River basin. The most abundant class of QACs were dialkyldimethylammonium compounds (DADMACs, with C8 to C18 carbon chain lengths; median ?DADMAC = 26 ?g/g), followed by benzylalkyldimethylammonium compounds (BAC, C12-C18; 1.5 ?g/g), and alkyltrimethylammonium compounds (ATMAC, primarily C16 and C18; 0.52 ?g/g). The concentrations of total QACs are higher than those of other conventional organic contaminants determined on the same samples (e.g., median ?PAH level of 2.1 ?g/g). Comparatively high concentrations, correlations with sewage derived contaminants, and the relatively constant compositions of QACs observed over large areas suggest that many sediment-sorbed QACs can be relatively persistent in receiving waters. Unusually large concentration-dependent sorption is considered as a mechanism that likely affects persistence of these intrinsically biodegradable chemicals under field conditions. There has been comparatively little field-based research on these classes of cationic surfactants; given the levels of QACs observed here, it is suggested that further investigation is warranted. PMID:20804121

Li, Xiaolin; Brownawell, Bruce J

2010-10-01

197

Integrating Conjugative Elements as Vectors of Antibiotic, Mercury, and Quaternary Ammonium Compound Resistance in Marine Aquaculture Environments  

PubMed Central

The presence of SXT/R391-related integrating conjugative elements (ICEs) in bacterial strains isolated from fish obtained from marine aquaculture environments in 2001 to 2010 in the northwestern Iberian Peninsula was studied. ICEs were detected in 12 strains taxonomically related to Vibrio scophthalmi (3 strains), Vibrio splendidus (5 strains), Vibrio alginolyticus (1 strain), Shewanella haliotis (1 strain), and Enterovibrio nigricans (2 strains), broadening the known host range able to harbor SXT/R391-like ICEs. Variable DNA regions, which confer element-specific properties to ICEs of this family, were characterized. One of the ICEs encoded antibiotic resistance functions in variable region III, consisting of a tetracycline resistance locus. Interestingly, hot spot 4 included genes providing resistance to rifampin (ICEVspPor2 and ICEValPor1) and quaternary ammonium compounds (QACs) (ICEEniSpa1), and variable region IV included a mercury resistance operon (ICEVspSpa1 and ICEEniSpa1). The S exclusion group was more represented than the R exclusion group, accounting for two-thirds of the total ICEs. Mating experiments allowed ICE mobilization to Escherichia coli strains, showing the corresponding transconjugants' rifampin, mercury, and QAC resistance. These results show the first evidence of ICEs providing rifampin and QAC resistances, suggesting that these mobile genetic elements contribute to the dissemination of antimicrobial, heavy metal, and QAC resistance determinants in aquaculture environments.

Rodriguez-Blanco, Arturo; Lemos, Manuel L.

2012-01-01

198

The synergistic effect of organic silicone quaternary ammonium salt and 5-fluorouracil on hepatocellular carcinoma in vitro and in vivo.  

PubMed

Hepatocellular carcinoma (HCC) is the third most common type of cancer worldwide, causing over 370 000 deaths per year, with approximately half of them in China. Chemotherapy is the optimal treatment for patients with advanced HCC, although chemoresistance has become a significant obstacle to successful liver cancer surgery. In this paper, we have assessed the characteristics of drugs to explore the effects of individual and combined action of organic silicone quaternary ammonium salt (Jieyoushen) and 5-fluorouracil (5-FU). The results of MTT assays showed that single and combined action of Jieyoushen and 5-FU can inhibit the proliferation of liver carcinoma cell lines in a dose-dependent and time-dependent manner, respectively. Electron microscopy and Hoechst 33342 staining showed characteristic apoptotic bodies in apoptotic cells treated with Jieyoushen and 5-FU. Flow cytometry results indicated that the percentage of cells at G0/G1 phase gradually increased, whereas it gradually decreased during the S phase after treatment. Taken together, these results suggest that the combination of Jieyoushen with 5-FU exerts a synergistic anticancer effect on HCC growth and that targeted therapeutic strategies may improve HCC sensitivity to chemotherapy. PMID:25072280

Wang, Juan-Xia; Zhang, Ling-Yi; Zhang, Jun; Ding, Hui; Wang, Dong-Min; Wang, Zhi-Ping

2014-09-01

199

Cytotoxic evaluation of some 3,5-diarylidene-4-piperidones and various related quaternary ammonium compounds and analogs.  

PubMed

A number of 3,5-diarylidene-4-piperidones (1) and some related quaternary ammonium salts (5) as well as closely related analogs were prepared principally as candidate cytotoxic agents in two screens. The first test system used an average of 54 human tumor cell lines from eight neoplastic diseases, namely leukemia, melanoma, colon, non-small-cell lung, small-cell lung, central nervous system, ovarian, and renal cancers. Selective toxicity was demonstrated by some of the compounds, especially toward leukemia. The second screen used L1210 lymphoid leukemia cells. In general, the compounds were less cytotoxic than the reference drug melphalan in both screens. Linear plots were made between the Hammett (sigma), fragment (f), and molar refractivity (MR) constants of the nuclear substituents in series 1 and 5 with the IC50 figures of both the human tumor cell lines and L1210 cells. Evaluation against the human tumor cell lines revealed that increases in the f values were correlated with elevation of cytotoxicity in both series 1 and 5; MR constants were also important in series 5. In the L1210 screen, sigma and MR constants were positively correlated with cytotoxicity. X-ray crystallography was undertaken on 3,5-bis-[[4'-(methylthio)phenyl]methylene]-1-methyl-4-piperidone methiodide (5d), which had significant cytotoxicity, and 3,5-bis(4-pyridylmethylene)-1-methyl-4-piperidone methiodide (6), which was virtually inactive in both screens.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7983596

Dimmock, J R; Arora, V K; Quail, J W; Pugazhenthi, U; Allen, T M; Kao, G Y; De Clercq, E

1994-08-01

200

Nitric oxide-releasing quaternary ammonium-modified poly(amidoamine) dendrimers as dual action antibacterial agents.  

PubMed

Herein we describe the synthesis of nitric oxide (NO)-releasing quaternary ammonium (QA)-functionalized generation 1 (G1) and generation 4 (G4) poly(amidoamine) (PAMAM) dendrimers. Dendrimers were modified with QA moieties of different alkyl chain lengths (i.e., methyl, butyl, octyl, dodecyl) via a ring-opening reaction. The resultant secondary amines were then modified with N-diazeniumdiolate NO donors to yield NO-releasing QA-modified PAMAM dendrimers capable of spontaneous NO release (payloads of ~0.75 ?mol/mg over 4 h). The bactericidal efficacy of individual (i.e., non-NO-releasing) and dual action (i.e., NO-releasing) QA-modified PAMAM dendrimers was evaluated against Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa bacteria. Bactericidal activity was found to be dependent on dendrimer generation, QA alkyl chain length, and bacterial Gram class for both systems. Shorter alkyl chains (i.e., methylQA, butylQA) demonstrated increased bactericidal activity against P. aeruginosa versus S. aureus for both generations, with NO release markedly enhancing overall killing. PMID:24797526

Worley, Brittany V; Slomberg, Danielle L; Schoenfisch, Mark H

2014-05-21

201

Gamma radiation-induced grafting of acrylamide and dimethyl diallyl ammonium chloride onto starch.  

PubMed

Corn starch graft copolymers were prepared from acrylamide/dimethyl diallyl ammonium chloride binary monomers (AM/DMDAAC) by a simultaneous radiation grafting method, and were characterized by FTIR and (1)H NMR techniques, weight measurement and titration method. The copolymers with high grafting ratio and high grafting efficiency of binary monomers were achieved at absorbed doses of 2 kGy and 3 kGy using a 6:9.8:4.2 (w/w/w) ratio of starch/AM/DMDAAC, but their cationic degrees were low. Grafting ratio, grafting efficiency and cationic degree of the copolymers increased with increasing AM content in comonomer mixtures and then decreased at 3kGy using a 6:14 ratio of starch:total comonomers, but their cationic degrees generally decreased with increasing AM content. The grafting ratio, the grafting efficiency and the cationic degree of the copolymers increased, but the grafting efficiency of DMDAAC decreased with varying starch/(AM+DMDAAC) ratio from 6:3 to 6:18 at 3 kGy by using a fixed 7:3 ratio of AM:DMDAAC. PMID:23218310

Lv, Xiaohua; Song, Weiqiang; Ti, Yongzhou; Qu, Lingbo; Zhao, Zhiwei; Zheng, Hongjuan

2013-01-30

202

Joint action of binary mixtures of cetyltrimethyl ammonium chloride and aromatic hydrocarbons on Chlorella vulgaris.  

PubMed

The joint action of binary mixtures of cetyltrimethyl ammonium chloride (CTAC), a cationic surfactant, and six aromatic hydrocarbons (AHs) on green algae Chlorella vulgaris was investigated. In single systems, inhibition efficiency of CTAC on the growth of algae was much higher than that of AHs (benzene, toluene, phenol, nitrobenzene, phenanthrene and fluoranthene). In combined systems, the toxicity of CTAC was enhanced by low concentrations of AHs. 96 h EC(50) value of CTAC varied from 145±13.35-56±8.27 to 56±8.27-226±8.22 ?g/L when exposed to 0-1.13 and 1.13-100.84 ?g/L fluoranthene, respectively. Zeta potential of algae initially increased and then decreased with the increase of fluoranthene concentration, whereas residual CTAC concentration displayed an opposite trend in the combined system. These results of this investigation showed that fluoranthene influenced the sorption of CTAC by C. vulgaris. The above results indicated that cationic surfactants and AHs have synergetic toxic effects on aquatic biota. PMID:20708266

Ge, Fei; Xu, Yin; Zhu, Runliang; Yu, Fangqin; Zhu, Menjun; Wong, Minghung

2010-10-01

203

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

NASA Astrophysics Data System (ADS)

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 been derived as rAM = 0.23 and rDMC = 1.40 at pH 6.8. Initial emulsions and final inverse latexes displayed the same broad size distribution. The effects of dose rate, concentration and composition of the monomer, emulsifier concentration, etc. on polymerization rate and intrinsic viscosity of polymer have been examined. The rate of polymerization ( Rp) can be represented by Rp ? D0.87[M] 1.37[E] 0.53. The overall activation activation energy for the rate of polymerization is 16.9 kJ/mol (32-55°C). Based on these experimental results, some aspects of the polymerization mechanism are discussed.

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

204

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

NASA Astrophysics Data System (ADS)

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 been derived as ram = 0.23 and rdmc = 1.40 at pH 6.8. Initial emulsions and final inverse latexes displayed the same broad size distribution. The effects of dose rate, concentration and composition of the monomer, emulsifier concentration, etc. on polymerization rate and intrinsic viscosity of polymer have been examined. The rate of polymerization (Rp) can be represented by Rp ? D0.87[M]1.37[E]0.53. The overall activation energy for the rate of polymerization is 16.9 kJ/mol (32-55°C). Based on these experimental results, some aspects of the polymerization mechanism are discussed.

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

1997-09-01

205

THE EFFECTS OF PARATHORMONE AND AMMONIUM CHLORIDE ON THE BONES OF RABBITS  

PubMed Central

1. A very large single dose of parathormone produced rapid and extensive decalcification of the bones of a young rabbit. 2. Gradually increased doses of parathormone failed to produce significant changes in the bones of young and fully grown adult rabbits. 3. Ammonium chloride, administered by stomach tube was without effect on the bones, when given to rabbits treated with parathormone or to otherwise untreated rabbits. 4. Calcium lactate did not promote the appearance of signs of parathormone overdosage in rabbits during treatment, nor were metastatic calcifications observed in the soft tissues after termination of the experiment. 5. The rabbit is relatively very resistant to the decalcifying effects of gradually increased repeated doses of parathormone, and therefore is not satisfactory material for experimental studies of bone changes of chronic hyperparathyroidism. 6. The appearance of actively transforming bones of a young growing rabbit, particularly at the sites of rapid growth, is not to be confused with the more severe fibrous processes produced by parathormone in guinea pigs, dogs and rats.

Jaffe, Henry L.; Bodansky, Aaron; Blair, John E.

1932-01-01

206

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

207

A Contributive Study on the Stripping of Zinc(II) from Loaded TBP Using an Ammonia\\/Ammonium Chloride Solution  

Microsoft Academic Search

The stripping of zinc(II) from undiluted and 80 v\\/v% TBP in low aromatic kerosene by means of ammonia\\/ammonium chloride solution has been studied. It was found that the equilibrium in the system was reached within 2–3 min of vigorous shaking of aqueous and organic phases. The stripping isotherms for zinc, when using undiluted or 80% TBP and 10% or 1.8% hydrochloric

Ivo V. Mishonov; Krzysztof Alejski; Jan Szymanowski

2004-01-01

208

Ammonium Chloride–Catalyzed One-Pot Synthesis of Tetrahydrobenzo[?]xanthen-11-one Derivatives Under Solvent-Free Conditions  

Microsoft Academic Search

A one-pot, multicomponent reaction of aldehydes, dimedone, and ?-naphthols is described for the preparation of 12-aryl- or 12-alkyl-8,9,10,12-tetrahydrobenzo[?]xanthen-11-one derivatives using ammonium chloride as a mild, inexpensive, and environmentally benign catalyst under solvent-free conditions. Different types of aldehyde and ?-naphthol derivatives are used in the reaction, and in all cases the products were synthesized successfully.

Naser Foroughifar; Akbar Mobinikhaledi; Hassan Moghanian; Reza Mozafari; Hamid R. M. Esfahani

2011-01-01

209

Sorption studies of chromium(VI) onto new ion exchanger with tertiary amine, quaternary ammonium and ketone groups.  

PubMed

A new acrylic anion exchanger with both tertiary and quaternary ammonium as well as ketone groups in the structural unit has been prepared by the nucleophilic substitution reaction of aminolyzed vinylacetate:acrylonitrile:divinylbenzene copolymer of porosity structure in the swelling state with 2-chloroacetone as a halogenated compound. The new compound exhibits better qualities of strong base exchange capacity than the weak base anion exchangers. The obtained acrylic anion exchanger was used to remove Cr(VI) from the aqueous solution. Batch adsorption studies have been carried out to determine the effect of contact time, concentration of hexavalent chromium in the solution and pH on the sorption capacity. The kinetic parameters were determined on the basis of the static results. The thermodynamic parameters of Cr(VI) sorption process on the anion exchanger were calculated based on the Langmuir and Freundlich isotherms. Sorption was studied in the pH range of 1.5-7 and it was found that it depends on the solution acidity. At the pH values of 3.5 and 7 the anion exchanger exhibited large values of chromium sorption capacity. The speciation of chromium was investigated in the studied pH range by the Diffuse Reflectance Spectroscopy (DRS) method. Reduction of chromium(VI) to chromium(III) under acidic conditions was observed. The performed acrylic strong base anion exchanger is superior compared to the conventional one based on the styrene:divinylbenzene matrix due to its ability for reposition of the long spacer arm for providing exchange sites, hydrophilic character of matrix, and possible hydrogen bonds provided by carbonyl functional groups. PMID:21497994

Wójcik, Grzegorz; Neagu, Violeta; Bunia, Ion

2011-06-15

210

Diverse inhibitory actions of quaternary ammonium cholinesterase inhibitors on Torpedo nicotinic ACh receptors transplanted to Xenopus oocytes  

PubMed Central

Background and purpose: This work was aimed at comparing and analysing the effects and mechanisms of action of the quaternary ammonium cholinesterase inhibitors (QChEIs) BW284c51, decamethonium and edrophonium, on nicotinic ACh receptor (nAChR) function. Experimental approach: nAChRs purified from Torpedo electroplax were transplanted to oocytes and currents elicited by ACh (IACh) either alone or in presence of these QChEIs were recorded. Key results: None of the QChEIs, by itself, elicited changes in membrane conductance; however, when co-applied with ACh, all of them decreased IACh in a concentration-dependent way. The mechanisms of nAChR inhibition were different for these QChEIs. BW284c51 blockade was non-competitive and voltage-dependent, although it also affected the nH of the dose-response curve. By contrast, decamethonium and edrophonium inhibition, at –60 mV, was apparently competitive and did not modify either desensitisation or nH. Decamethonium effects were voltage-independent and washed out slowly after its removal; by contrast, edrophonium blockade had strong voltage dependence and its effects disappeared quickly after its withdrawal. Analysis of the voltage-dependent blockade indicated that BW284c51 bound to a shallow site into the channel pore, whereas edrophonium bound to a deeper locus. Accordingly, additive inhibitory effects on IACh were found among any pairs of these QChEIs. Conclusions and implications: The tested QChEIs bound to the nAChR at several and different loci, which might account for their complex inhibitory behaviour, acting both as allosteric effectors and, in the case of BW284c51 and edrophonium, as open channel blockers.

Olivera-Bravo, Silvia; Ivorra, Isabel; Morales, Andres

2007-01-01

211

Effect of quaternary ammonium and silver nanoparticle-containing adhesives on dentin bond strength and dental plaque microcosm biofilms  

PubMed Central

Objectives Antibacterial bonding agents are promising to hinder the residual and invading bacteria at the tooth-restoration interfaces. The objectives of this study were to develop an antibacterial bonding agent by incorporation of quaternary ammonium dimethacrylate (QADM) and nanoparticles of silver (NAg), and to investigate the effect of QADM-NAg adhesive and primer on dentin bond strength and plaque microcosm biofilm response for the first time. Methods Scotchbond Multi-Purpose adhesive and primer were used as control. Experimental adhesive and primer were made by adding QADM and NAg into control adhesive and primer. Human dentin shear bond strengths were measured (n = 10). A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate biofilm metabolic activity, colony-forming unit (CFU) counts, lactic acid production, and live/dead staining assay (n = 6). Results Adding QADM and NAg into adhesive and primer did not compromise the dentin shear bond strength which ranged from 30 to 35 MPa (p > 0.1). Scanning electron microscopy (SEM) examinations revealed numerous resin tags, which were similar for the control and the QADM and NAg groups. Adding QADM or NAg markedly reduced the biofilm viability, compared to adhesive control. QADM and NAg together in the adhesive had a much stronger antibacterial effect than using each agent alone (p < 0.05). Adding QADM and NAg in both adhesive and primer had the strongest antibacterial activity, reducing metabolic activity, CFU, and lactic acid by an order of magnitude, compared to control. Significance Without compromising dentin bond strength and resin tag formation, the QADM and NAg containing adhesive and primer achieved strong antibacterial effects against microcosm biofilms for the first time. QADM-NAg adhesive and primer are promising to combat residual bacteria in tooth cavity and invading bacteria at the margins, thereby to inhibit secondary caries. QADM and NAg incorporation may have a wide applicability to other dental bonding systems.

Zhang, Ke; Melo, Mary Anne S.; Cheng, Lei; Weir, Michael D.; Bai, Yuxing; Xu, Hockin H. K.

2012-01-01

212

Assessment of bactericidal effects of quaternary ammonium-based antibacterial monomers in combination with colloidal platinum nanoparticles.  

PubMed

Pretreatment of dentin using colloidal platinum nanoparticles (CPtN) can enhance the bond strength of dentin adhesives. However, the combination of CPtN, which is negatively charged, with cationic monomer-containing adhesive may reduce the antibacterial activity of the original material. Thus, the purpose of this study was to assess the effect of CPtN on the bactericidal activity of two cationic antibacterial monomers, 12-methacryloyloxydodecylpyridinium bromide (MDPB) and methacryloxylethyl cetyl dimethyl ammonium chloride (DMAE-CB). The rapid killing effects of the two monomers against planktonic or attached Streptococcus mutans in the presence or absence of CPtN were examined by viable cell counts. The measurement of minimum inhibitory and bactericidal concentrations demonstrated that CPtN up to 2.5 mM has no antibacterial activity. In the absence of CPtN, rapid killing of both planktonic and attached Streptococcus mutans were achieved by the two cationic monomers. Combination with 0.1 mM CPtN did not reduce the bactericidal effects of the two monomers, indicating that CPtN may be used as a pretreatment with antibacterial adhesives. PMID:22277619

Ma, Sai; Izutani, Naomi; Imazato, Satoshi; Chen, Ji-Hua; Kiba, Wakako; Yoshikawa, Ranna; Takeda, Kahoru; Kitagawa, Haruaki; Ebisu, Shigeyuki

2012-02-01

213

Effect of a Novel Quaternary Ammonium Methacrylate Polymer (QAMP) on Adhesion and Antibacterial Properties of Dental Adhesives.  

PubMed

This study investigated the resin-dentin bond strength (?TBS), degree of conversion (DC), and antibacterial potential of an innovative adhesive system containing a quaternary ammonium methacrylate polymer (QAMP) using in situ and in vitro assays. Forty-two human third molars were flattened until the dentin was exposed and were randomly distributed into three groups of self-etching adhesive systems: Clearfil™ SE Bond containing 5% QAMP (experimental group), Clearfil™ Protect Bond (positive control) and Clearfil™ SE Bond (negative control). After light curing, three 1 mm-increments of composite resin were bonded to each dentin surface. A total of thirty of these bonded teeth (10 teeth per group) was sectioned to obtain stick-shaped specimens and tested under tensile stress immediately, and after 6 and 12 months of storage in distilled water. Twelve bonded teeth (4 teeth per group) were longitudinally sectioned in a mesio-to-distal direction to obtain resin-bonded dentin slabs. In situ DC was evaluated by micro-Raman spectroscopy. In vitro DC of thin films of each adhesive system was measured using Fourier transform infrared spectroscopy. In vitro susceptibility tests of these three adhesive systems were performed by the minimum inhibitory/minimum bactericidal concentration (MIC/MBC) assays against Streptococcus mutans, Lactobacillus casei, and Actinomyces naeslundii. No statistically significant difference in ?TBS was observed between Clearfil™ SE Bond containing 5% QAMP and Clearfil™ SE Bond (p > 0.05) immediately, and after 6 and 12 months of water storage. However Clearfil™ Protect Bond showed a significant reduction of ?TBS after 12 months of storage (p = 0.039). In addition, QAMP provided no significant change in DC after incorporating into Clearfil™ SE Bond (p > 0.05). Clearfil™ SE Bond containing 5% QAMP demonstrated MIC/MBC values similar to the positive control against L. casei and A. naeslundii and higher than the negative control for all evaluated bacterial strains. The use of QAMP in an adhesive system demonstrated effective bond strength, a suitable degree of conversion, and adequate antibacterial effects against oral bacteria, and may be useful as a new approach to provide long-lasting results for dental adhesives. PMID:24853131

Pupo, Yasmine M; Farago, Paulo Vitor; Nadal, Jessica M; Simão, Luzia C; Esmerino, Luís Antônio; Gomes, Osnara M M; Gomes, João Carlos

2014-01-01

214

Quaternary ammonium salt of U50488H, a new ?-opioid receptor agonist, protects rat heart against ischemia/reperfusion injury.  

PubMed

To keep U50488H from going through the blood-brain barrier, U50488H, a selective ?-opioid receptor agonist, was structurally transformed into its quaternary ammonium salt (Q-U50488H). The effect of Q-U50488H on ischemic/reperfused myocardium and its underlying mechanisms were also investigated. U50488H was transformed into Q-U50488H, which was identified with mass spectrometry. The existences of U50488H and Q-U50488H in serum and brain tissue fluid were determined by high performance liquid chromatography (HPLC). SD rats' hearts were subjected to 30min of ischemia followed by 120min of reperfusion in vivo. After reperfusion, myocardial enzymes and free radicals in serum, area of myocardial infarction, cardiomyocyte apoptosis and the expression of Kir6.2 in rats' myocardium were determined. Molecular weight and solubility of Q-U50488H were higher than those of U50488H. Result of HPLC showed that Q-U50488H existed in serum but not in brain tissue after Q-U50488H intravenous injection. However, U50488H was detected in both serum and brain tissue. Compared with the I/R group, treatment with Q-U50488H significantly attenuated the activity of LDH, CK, AST/GOT and content of MDA in serum, upregulated the activity of SOD, and increased the expression of myocardial Kir6.2. It also reduced myocardial infarct size and cardiomyocyte apoptosis induced by I/R. Moreover, pretreatment with Nor-BNI (a selective ?-opioid receptor antagonist), 5-HD and glibenclamide (KATP antagonists) abolished the effects of Q-U50488H. It is suggested Q-U50488H, a new compound of ?-opioid receptor agonist, which is not able to pass the blood-brain barrier, elicits a protective effect against myocardial ischemia/reperfusion injury. The cardioprotective effect of Q-U50488H is associated with the opening of KATP. PMID:24855042

Wang, Qianmei; Sun, Yang; Li, Juan; Xing, Wenjuan; Zhang, Shumiao; Gu, Xiaoming; Feng, Na; Zhao, Lei; Fan, Rong; Wang, Yuemin; Yin, Wen; Pei, Jianming

2014-08-15

215

Effect of a Novel Quaternary Ammonium Methacrylate Polymer (QAMP) on Adhesion and Antibacterial Properties of Dental Adhesives  

PubMed Central

This study investigated the resin–dentin bond strength (?TBS), degree of conversion (DC), and antibacterial potential of an innovative adhesive system containing a quaternary ammonium methacrylate polymer (QAMP) using in situ and in vitro assays. Forty-two human third molars were flattened until the dentin was exposed and were randomly distributed into three groups of self-etching adhesive systems: Clearfil™ SE Bond containing 5% QAMP (experimental group), Clearfil™ Protect Bond (positive control) and Clearfil™ SE Bond (negative control). After light curing, three 1 mm-increments of composite resin were bonded to each dentin surface. A total of thirty of these bonded teeth (10 teeth per group) was sectioned to obtain stick-shaped specimens and tested under tensile stress immediately, and after 6 and 12 months of storage in distilled water. Twelve bonded teeth (4 teeth per group) were longitudinally sectioned in a mesio-to-distal direction to obtain resin-bonded dentin slabs. In situ DC was evaluated by micro-Raman spectroscopy. In vitro DC of thin films of each adhesive system was measured using Fourier transform infrared spectroscopy. In vitro susceptibility tests of these three adhesive systems were performed by the minimum inhibitory/minimum bactericidal concentration (MIC/MBC) assays against Streptococcus mutans, Lactobacillus casei, and Actinomyces naeslundii. No statistically significant difference in ?TBS was observed between Clearfil™ SE Bond containing 5% QAMP and Clearfil™ SE Bond (p > 0.05) immediately, and after 6 and 12 months of water storage. However Clearfil™ Protect Bond showed a significant reduction of ?TBS after 12 months of storage (p = 0.039). In addition, QAMP provided no significant change in DC after incorporating into Clearfil™ SE Bond (p > 0.05). Clearfil™ SE Bond containing 5% QAMP demonstrated MIC/MBC values similar to the positive control against L. casei and A. naeslundii and higher than the negative control for all evaluated bacterial strains. The use of QAMP in an adhesive system demonstrated effective bond strength, a suitable degree of conversion, and adequate antibacterial effects against oral bacteria, and may be useful as a new approach to provide long-lasting results for dental adhesives.

Pupo, Yasmine M.; Farago, Paulo Vitor; Nadal, Jessica M.; Simao, Luzia C.; Esmerino, Luis Antonio; Gomes, Osnara M. M.; Gomes, Joao Carlos

2014-01-01

216

Biocidal quaternary ammonium resin  

NASA Technical Reports Server (NTRS)

Activated carbon (charcoal) and polymeric resin sorbents are widely used in the filtration and treatment of drinking water, mainly to remove dissolved organic and inorganic impurities and to improve the taste. Earlier hopes that activated carbon might "disinfect' water proved to be unfounded. The feasibility of protecting against microbial infestation in charcoal and resin beds such as those to be incorporated into total water reuse systems in spacecraft was investigated. The biocidal effect of IPCD (insoluable polymeric contact disinfectants) in combination with a representative charcoal was assessed. The ion exchange resins (IPCD) were shown to adequately protect charcoal and ion exchange beds.

Janauer, G. E.

1983-01-01

217

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

PubMed

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 of the species Pseudomonas putida (Syst. Appl. Microbiol. 24 (2001) 252). Two bacteria were isolated with DM, referred to as strains DM 1 and DM 2, respectively. Based on 16S-rDNA analysis, they provided 97% (DM 1) and 98% (DM 2) identities to the closest related strain Zoogloea ramigera Itzigsohn 1868AL. Both strains were long, slim, motile rods but only DM 1 showed the floc forming activity, which is typical for representatives of the genus Zoogloea. Using MM we isolated a Gram-negative, non-motile rod referred to as strain MM 1. The 16S-rDNA sequence of the isolated bacterium revealed 94% identities (best match) to Rhodobacter sphaeroides only. The strains MM 1 and DM 1 exclusively grew with the QAA which was used for their isolation. DM 2 was also utilizing TM as sole source of carbon and nitrogen. However, all of the isolated bacteria were growing with the natural and structurally related compound choline. PMID:15900970

Kaech, Andres; Vallotton, Nathalie; Egli, Thomas

2005-04-01

218

Occupational asthma due to indirect exposure to lauryl dimethyl benzyl ammonium chloride used in a floor cleaner.  

PubMed Central

The case is described of a 44 year old pharmacist who developed severe occupational asthma threatening his continued employment, confirmed by serial measurement of peak expiratory flow at home and work. The cause was found to be the cleaning agent used in his office when it was unoccupied. Bronchial challenge testing identified the specific agent to which he was sensitised as lauryl dimethyl benzyl ammonium chloride, a constituent of the floor cleaner. Substitution of this floor cleaner by a simple detergent cleaner led to a substantial improvement in his asthma, confirmed by repeated serial peak flow measurements. Images

Burge, P. S.; Richardson, M. N.

1994-01-01

219

Selective Detection of Carbohydrates and Their Peptide Conjugates by ESI-MS Using Synthetic Quaternary Ammonium Salt Derivatives of Phenylboronic Acids  

NASA Astrophysics Data System (ADS)

We present new tags based on the derivatives of phenylboronic acid and apply them for the selective detection of sugars and peptide-sugar conjugates in mass spectrometry. We investigated the binding of phenylboronic acid and its quaternary ammonium salt (QAS) derivatives to carbohydrates and peptide-derived Amadori products by HR-MS and MS/MS experiments. The formation of complexes between sugar or sugar-peptide conjugates and synthetic tags was confirmed on the basis of the unique isotopic distribution resulting from the presence of boron atom. Moreover, incorporation of a quaternary ammonium salt dramatically improved the efficiency of ionization in mass spectrometry. It was found that the formation of a complex with phenylboronic acid stabilizes the sugar moiety in glycated peptides, resulting in simplification of the fragmentation pattern of peptide-derived Amadori products. The obtained results suggest that derivatization of phenylboronic acid as QAS is a promising method for sensitive ESI-MS detection of carbohydrates and their conjugates formed by non-enzymatic glycation or glycosylation.

Kijewska, Monika; Kuc, Adam; Kluczyk, Alicja; Waliczek, Mateusz; Man-Kupisinska, Aleksandra; Lukasiewicz, Jolanta; Stefanowicz, Piotr; Szewczuk, Zbigniew

2014-04-01

220

Selective Detection of Carbohydrates and Their Peptide Conjugates by ESI-MS Using Synthetic Quaternary Ammonium Salt Derivatives of Phenylboronic Acids  

NASA Astrophysics Data System (ADS)

We present new tags based on the derivatives of phenylboronic acid and apply them for the selective detection of sugars and peptide-sugar conjugates in mass spectrometry. We investigated the binding of phenylboronic acid and its quaternary ammonium salt (QAS) derivatives to carbohydrates and peptide-derived Amadori products by HR-MS and MS/MS experiments. The formation of complexes between sugar or sugar-peptide conjugates and synthetic tags was confirmed on the basis of the unique isotopic distribution resulting from the presence of boron atom. Moreover, incorporation of a quaternary ammonium salt dramatically improved the efficiency of ionization in mass spectrometry. It was found that the formation of a complex with phenylboronic acid stabilizes the sugar moiety in glycated peptides, resulting in simplification of the fragmentation pattern of peptide-derived Amadori products. The obtained results suggest that derivatization of phenylboronic acid as QAS is a promising method for sensitive ESI-MS detection of carbohydrates and their conjugates formed by non-enzymatic glycation or glycosylation.

Kijewska, Monika; Kuc, Adam; Kluczyk, Alicja; Waliczek, Mateusz; Man-Kupisinska, Aleksandra; Lukasiewicz, Jolanta; Stefanowicz, Piotr; Szewczuk, Zbigniew

2014-06-01

221

Selective Detection of Carbohydrates and Their Peptide Conjugates by ESI-MS Using Synthetic Quaternary Ammonium Salt Derivatives of Phenylboronic Acids.  

PubMed

We present new tags based on the derivatives of phenylboronic acid and apply them for the selective detection of sugars and peptide-sugar conjugates in mass spectrometry. We investigated the binding of phenylboronic acid and its quaternary ammonium salt (QAS) derivatives to carbohydrates and peptide-derived Amadori products by HR-MS and MS/MS experiments. The formation of complexes between sugar or sugar-peptide conjugates and synthetic tags was confirmed on the basis of the unique isotopic distribution resulting from the presence of boron atom. Moreover, incorporation of a quaternary ammonium salt dramatically improved the efficiency of ionization in mass spectrometry. It was found that the formation of a complex with phenylboronic acid stabilizes the sugar moiety in glycated peptides, resulting in simplification of the fragmentation pattern of peptide-derived Amadori products. The obtained results suggest that derivatization of phenylboronic acid as QAS is a promising method for sensitive ESI-MS detection of carbohydrates and their conjugates formed by non-enzymatic glycation or glycosylation. PMID:24687577

Kijewska, Monika; Kuc, Adam; Kluczyk, Alicja; Waliczek, Mateusz; Man-Kupisinska, Aleksandra; Lukasiewicz, Jolanta; Stefanowicz, Piotr; Szewczuk, Zbigniew

2014-06-01

222

Toxic effects of linear alkylbenzenesulfonate and quaternary alkylammonium chloride on Dunaliella sp. as measured by 1H-NMR analysis of glycerol  

Microsoft Academic Search

A new method to assess the toxic effects of linear alkylbenzenesulfonate (LAS : alkyl carbon number; 12) and quaternary alkylammonium chloride was established by using living green alga, Dunaliella sp.. This method is based on the 1H-NMR determination of glycerol which decreased quantitatively with increased concentrations of surfactants.The flagella immobilities and the cell mortalities following the exposure of LAS and

Akiko Utsunomiya; Tomohiko Watanuki; Kazuhiro Matsushita; Isao Tomita

1997-01-01

223

Monte Carlo Studies of the Orientational Order-Disorder Phase Transition in Solid Ammonium Chloride  

Microsoft Academic Search

Monte Carlo methods are used to study the phase transition in ammonium\\u000achloride from the orientationally ordered $\\\\delta$ phase to the orientationally\\u000adisordered $\\\\gamma$ phase. An effective pair potential is used to model the\\u000ainteraction between ions. Thermodynamic properties are computed in the\\u000acanonical and isothermal-isobaric ensembles. Each ammonium ion is treated as a\\u000arigidly rotating body and the lattice

Robert Q. Topperand; David L. Freeman

1994-01-01

224

The versatility of metal halide-quaternary ammonium salt catalysts for organic processes. From homogeneous to glass-encapsulated ion pairs  

Microsoft Academic Search

Ion pairs generated from transition metal halides and quaternary onium salts are versatile catalysts for many organic processes.\\u000a Under phase transfer conditions, RhCl3- and\\/or PtCl4-Aliquat 336 catalyze (a) double bond migration in allylic compounds, (b) disproportionation of cyclic 1,3-dienes, (c) selective transfer\\u000a reduction of alkenes, alkynes, ?,?-carbonyl compounds, and aroyl chlorides by polymethylhydrosiloxane, (d) hydrogenation of\\u000a double, triple, and aromatic

Jochanan Blum

1993-01-01

225

In situ continuous monitoring of chloride, nitrate and ammonium in a temporary stream Comparison with standard methods.  

PubMed

A multi-parameter probe was used for in situ chloride, nitrate and ammonium measurements in a temporary stream (Ribeira da Pardiela, in the South of Portugal). Comparison with standard analytical methods was performed for all elements. For chloride, the results of the probe depicted the same behaviour as that obtained with the standard method, although it is clear that the matrix effects were present. For nitrate, the results obtained with the probe were in agreement with the other standard methods used, except for samples collected during drought, when the stream water became brownish and exhaled an offensive smell, due to the decomposition of organic matter. For ammonium, surprisingly the probe show to be the best option, the phenate method being affected by matrix effects. The results still suggest an interference of the bicarbonate ion on nitrate determination, but standard additions approach was shown to minimize most of the matrix effects. Recoveries were reasonable to good for all the three anions under scrutiny. PMID:19071428

Capelo, S; Mira, F; de Bettencourt, A M

2007-02-28

226

Increased serum triglycerides and reduced HDL cholesterol in male rats after intake of ammonium chloride for 3 weeks  

PubMed Central

Background Previous data suggested that intake of sodas and other acid beverages might be associated with increased levels of serum triglycerides, lowered HDL cholesterol, and increased formation of mono unsaturated fatty acids, which are the preferred ones for triglyceride synthesis. The present work is an extension of these studies. Methods Thirty male rats were divided into 3 groups. All groups were given the same food, but various beverages: water (W), ammonium chloride, 200 mmol/L (AC), or sodium bicarbonate, 200 mmol/L (SB). Serum triglycerides, HDL cholesterol, and the fatty acid distribution in total serum lipids were determined. Delta9-desaturase in serum lipids was estimated by the ratio of palmitoleic to palmitic acid, and by the oleic/stearic acid ratio. Correlation and ANOVA were used to study associations and group differences. Results After 3 weeks, the AC group had higher triglyceride concentration and higher Delta9 desaturase indexes, but lower serum HDL and body weight as compared with the SB and W groups. In each of the groups, the oleic acid/stearic acid ratio correlated positively with serum triglycerides; in the pooled group the correlation coefficient was r?=?0.963, p<0.01. Conclusions Rats ingesting ammonium chloride as compared with sodium bicarbonate responded with increased desaturase indexes, increased serum triglycerides, and lowered HDL cholesterol concentration, thereby possibly contributing to explain the increased triglyceride concentration previously observed in subjects with a frequent intake of acid beverages, such as sodas containing carbonic acid, citric acid, and phosphoric acid.

2013-01-01

227

Radiation Stability of Benzyl Tributyl Ammonium Chloride Towards Technetium-99 Extraction  

SciTech Connect

A closed nuclear fuel cycle combining new separation technologies along with generation III and generation IV reactors is a promising way to achieve a sustainable energy supply. But it is important to keep in mind that future recycling processes of used nuclear fuel (UNF) must minimize wastes, improve partitioning process, and integrate waste considerations into processes. New separation processes are being developed worldwide to complement the actual industrialized PUREX process which selectively separates U(VI) and Pu(IV) from the raffinate. As an example, low nitric acid concentration in the aqueous phase of a UREX based process will co-extract U(VI) and Tc(VII) by tri-n-butyl phosphate (TBP). Technetium (Tc-99) is recognized to be one of the most abundant, long-lived radiotoxic isotopes in UNF (half-life, t1/2 = 2.13 × 105 years), and as such, it is targeted in UNF separation strategies for isolation and encapsulation in solid waste forms for final disposal in a nuclear waste repository. Immobilization of Tc-99 by a durable solid waste form is a challenge, and its fate in new advanced technology processes is of importance. It is essential to be able to quantify and locate 1) its occurrence in any new developed flow sheets, 2) its chemical form in the individual phases of a process, 3) its potential quantitative transfer in any waste streams, and consequently, 4) its quantitative separation for either potential transmutation to Ru-100 or isolation and encapsulation in solid waste forms for ultimate disposal. Furthermore, as a result of an U(VI)-Tc(VII) co-extraction in a UREX-based process, Tc(VII) could be found in low level waste (LLW) streams. There is a need for the development of new extraction systems that would selectively extract Tc-99 from LLW streams and concentrate it for feed into high level waste (HLW) for either Tc-99 immobilization in metallic waste forms (Tc-Zr alloys), and/or borosilicate-based waste glass. Studies have been launched to investigate the suitability of new macrocompounds such as crown-ethers, aza-crown ethers, and resorcinarenes for the selective extraction of Tc-99 from nitric acid solutions. The selectivity of the ligand is important in evaluating potential separation processes and also the radiation stability of the molecule is essential for minimization of waste and radiolysis products. In this paper, we are reporting the extraction of TcO4- by benzyltributyl ammonium chloride (BTBA). Experimental efforts were focused on determining the best extraction conditions by varying the ligand’s matrix conditions and concentration, as well as varying the organic phase composition (i.e., diluent variation). Furthermore, the ligand has been investigated for radiation stability. The ?-irradiation was performed on the neat organic phases containing the ligand at different absorbed doses to a maximum of 200 kGy using external Co-60 source. Post-irradiation solvent extraction measurements will be discussed.

Jared Horkley; Audrey Roman; Keri Campbell; Ana Nunez; Amparo Espartero

2013-02-01

228

Preparation of a stationary phase with quaternary ammonium embedded group for selective separation of alkaloids based on ion-exclusion interaction.  

PubMed

A stationary phase (named QA C10) with quaternary ammonium embedded between a propyl and a decyl chain was synthesized by immobilization of N,N-dimethyldecylamine on chloropropyl-silica surface. A set of representative neutral, basic, and acidic compounds was employed to evaluate its chromatographic properties. The results illustrated that QA C10 was a mixed-mode stationary phase possessing both hydrophobic and ionic characteristics. The QA C10 stationary phase was further used for selective separation of alkaloids from Cortex phellodendri. Under acidic condition, alkaloids could be eluted in first 8 min, while other neutral and acidic fractions were retained better on QA C10 column. Then, obtained alkaloid fraction was analyzed by LC-MS/MS and 22 alkaloids were identified. Our study confirmed the advantages and application potential of the QA C10 stationary phase for alkaloids separation. PMID:23008235

Liu, Qiaoxia; Liang, Tu; Li, Kuiyong; Ke, Yanxiong; Jin, Yu; Liang, Xinmiao

2012-10-01

229

AGING EFFECTS ON THE PROPERTIES OF IMIDAZOLIUM, QUATERNARY AMMONIUM, PYRIDINIUM AND PYRROLIDINIUM-BASED IONIC LIQUIDS USED IN FUEL AND ENERGY PRODUCTION  

SciTech Connect

Ionic liquids are often cited for their excellent thermal stability, a key property for their use as solvents and in the chemical processing of biofuels. However, there has been little supporting data on the long term aging effect of temperature on these materials. Imizadolium, quaternary ammonium, pyridinium, and pyrrolidnium-based ionic liquids with the bis(trifluoromethylsulfonyl)imide and bis(perfluoroethylsulfonyl)imide anions were aged for 2520 hours (15 weeks) at 200?C in air to determine the effects of an oxidizing environment on their chemical structure and thermal stability over time. It was found that the minor changes in the cation chemistry could greatly affect the properties of the ILs over time.

Fox, E.

2013-08-13

230

Bis-azaaromatic quaternary ammonium salts as antagonists at nicotinic receptors mediating nicotine-evoked dopamine release: An investigation of binding conformation  

PubMed Central

A series of conformationally restricted bis-azaaromatic quaternary ammonium salts (3 and 4) have been designed and synthesized in order to investigate the possible binding conformations of N,N?-dodecane-1,12-diyl-bis-3-picolinium dibromide (bPiDDB; 2), a compound which potently inhibits neuronal nicotinic acetylcholine receptors (nAChRs) mediating nicotine-evoked dopamine release. The preliminary structure–activity relationships of these new analogues suggest that bPiDDB binds in an extended conformation at the nAChR binding site, and that flexibility of the linker may be important for its high potency in inhibiting nAChRs mediating nicotine-evoked dopamine release.

Zheng, Guangrong; Zhang, Zhenfa; Pivavarchyk, Marharyta; Deaciuc, Agripina G.; Dwoskin, Linda P.; Crooks, Peter A.

2014-01-01

231

Trp82 and Tyr332 are involved in two quaternary ammonium binding domains of human butyrylcholinesterase as revealed by photoaffinity labeling with [3H]DDF.  

PubMed

Purified butyrylcholinesterase (BuChE) was photolabeled by [3H]-p-N, N-dimethylamino benzene diazonium ([3H]DDF) to identify the quaternary ammonium binding sites on this protein [Ehret-Sabatier, L. , Schalk, I., Goeldner, M., and Hirth, C. (1992) Eur. J. Biochem. 203, 475-481]. The covalent photoincorporation occurs with a stoichiometry of one mole of probe per mole of inactivated site and could be fully prevented by several cholinergic inhibitors such as tacrine or tetramethylammonium. After complete deglycosylation of the enzyme using N-glycosidase F, the alkylated protein was trypsinolyzed and the digests were analyzed by HPLC coupled to ES-MS. A direct comparison of tryptic fragments from labeled and unlabeled BuChE allowed us to identify the tryptic peptide Tyr61-Lys103 as carrying the probe. Purification of the labeled peptides by anion-exchange chromatography gave a major radioactive peak which was further fractionated by reversed-phase HPLC leading to three, well-resolved, radioactive peaks. Microsequencing revealed that two of these peaks contained an overlapping sequence starting at Tyr61, while the third peak contained a sequence extending from Thr315. Radioactive signals could be unambiguously attributed to positions corresponding to residues Trp82 and Tyr332. This labeling study establishes the existence of two different binding domains for quaternary ammonium in BuChE and exemplifies additional cation/pi interactions in cholinergic proteins. This work strongly supports the existence of a peripheral anionic site in BuChE, implying residue Tyr332 as a key element. PMID:9671522

Nachon, F; Ehret-Sabatier, L; Loew, D; Colas, C; van Dorsselaer, A; Goeldner, M

1998-07-21

232

Trp279 is involved in the binding of quaternary ammonium at the peripheral site of Torpedo marmorata acetylcholinesterase.  

PubMed

Specific photoaffinity labelling of purified acetylcholinesterase from Torpedo marmorata by p-N,N-[3H]dimethylamino benzenediazonium and p-N,N-[3H]dibutylamino benzenediazonium derivatives was demonstrated. This occurred at the active site of the enzyme for lower concentrations of the probes and at the peripheral ammonium binding site for higher concentrations. The affinities and the rate constants of alkylation for each probe on both sites have been established. Specific labelling at the peripheral site of the enzyme with both probes allowed the identification of radio-labelled peptides having the common sequence K270PQELIDVEW. The radioactivity was always associated with the residue Trp279 indicating the preferential ammonium complexation with this aromatic residue. PMID:8306982

Schalk, I; Ehret-Sabatier, L; Bouet, F; Goeldner, M; Hirth, C

1994-01-15

233

The optical constants of several atmospheric aerosol species - Ammonium sulfate, aluminum oxide, and sodium chloride  

NASA Technical Reports Server (NTRS)

An investigation is conducted of problems which are related to a use of measured optical constants in the simulation of the optical constants of real atmospheric aerosols. The techniques of measuring optical constants are discussed, taking into account transmission measurements through homogeneous and inhomogeneous materials, the immersion of a material in a liquid of a known refractive index, the consideration of the minimum deviation angle of prism measurement, the interference of multiply reflected light, reflectivity measurements, and aspects of mathematical analysis. Graphs show the real and the imaginary part of the refractive index as a function of wavelength for aluminum oxide, NaCl, and ammonium sulfate. Tables are provided for the dispersion parameters and the optical constants.

Toon, O. B.; Pollack, J. B.; Khare, B. N.

1976-01-01

234

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

235

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

236

Self-assembled structures of anionic hydrophobically modified polyacrylamide with star-shaped trimeric and hexameric quaternary ammonium surfactants.  

PubMed

The self-assembly of a 1% hydrophobically modified and 30% hydrolyzed polyacrylamide (C12PAM) with cationic star-shaped oligomeric surfactants has been investigated by isothermal titration microcalorimetry, turbidimetry, ? potential, scanning electron microscopy, and (1)H NMR techniques. The oligomeric surfactants are composed of quaternary dodecyldimethylammonium ions with three or six hydrophobic chains connected by a polyamine spacer at the headgroup level, abbreviated as DTAD and PAHB, respectively. DTAD/C12PAM and PAHB/C12PAM mixed systems undergo the same aggregate transitions with increases in surfactant concentration from soluble networklike aggregates to precipitated denser and more cross-linked structures and then to soluble spherical aggregates. The networklike aggregates are generated at very low surfactant concentration. However, at the corresponding surfactant concentration without C12PAM, DTAD cannot form aggregates and PAHB forms only networklike aggregates with a very loose structure. The strong electrostatic and hydrophobic interaction of DTAD and PAHB with C12PAM and the hydrophobic interaction between the alkyl chains of DTAD and PAHB themselves evidently promote the formation of networklike aggregates. As the surfactant concentration increases, cationic surfactants become excessive. The molecular configuration is changed by the stronger hydrophobic association among the DTAD and PAHB molecules and the enhanced electrostatic repulsion between the mixed aggregates. Thus, the networklike aggregates transfer to spherical aggregates. PMID:24866373

Fan, Yaxun; Wu, Chunxian; Wang, Meina; Wang, Yilin; Thomas, Robert K

2014-06-17

237

The relation between structure and distribution of quaternary ammonium ions in mice and rats. Simple tetraalkylammonium and a series of m-substituted trimethylphenylammonium ions.  

PubMed

In order to determine the relationship between structure and distribution in mono-quaternary ammonium ions, the distribution of a series of 14C-labeled tetraalkylammonium and substituted trimethylanilinium ions in mice were comparatively studied by means of whole-body autoradiography and radioassay. The partition coefficient in n-octanol/water were also determined. With tetraalkylammonium, the concentration in blood and tissues decreased in the order of tetramethyl, tetraethyl and tetrapropylammonium, which was opposite to expectation based on their partition coefficient values, but was in the order of increasing steric hindrance at the cationic head. With substituted trimethylanilinium, the concentrations in the blood, skeletal and cardiac muscles, diaphragm and salivary gland after i.v. injection to mice increased in the order: m-NO2 less than Cl less than OCH3 less than H less than CH3. This did not coincide with the order of increasing the partition coefficients, but coincided with the decrease of the Hammett sigma-constants of the substituent. These results were interpreted on the basis of the assumption that the ion-pair formation of the cationic head with an anionic site of the tissue macromolecules played an important role in determining distribution. It was pointed out that although the lipophilic character of the molecule has been often cited as the most important factor determining the distribution of the drugs, the ionic character of the molecule or of the functional group can participate as a more important factor in determining tissue distribution. PMID:3794993

Tsubaki, H; Nakajima, E; Shigehara, E; Komai, T; Shindo, H

1986-09-01

238

Synthesis and in vivo biodisposition of [14C]-quaternary ammonium-melphalan conjugate, a potential cartilage-targeted alkylating drug.  

PubMed

For the purpose of developing more selective anticancer drugs that would concentrate in the malignant cartilaginous tumors (chondrosarcomas), and so improve therapeutic index through a reduction of side effects, a quaternary ammonium (QA) conjugate of melphalan was synthesized and labeled with (14)C by linking the QA moiety to nitrogen mustard via an amide bond. Comparative pharmacokinetic study of [(14)C]-melphalan and its [(14)C]-QA conjugate conducted on rats showed that the two compounds were principally excreted by the urinary way. The blood elimination of the QA conjugate was faster than that of the melphalan. In the other hand a higher rate of radioactivity derived of [(14)C]-MQA was found in feces. In the biodisposition for most organs, no striking differences were found between melphalan and its QA conjugate except for cartilages which exhibited more higher radioactivity level. Amounts of radioactivity derived from [(14)C]-QA conjugates measured in cartilaginous tissues until 1 h after injection demonstrate that the introduction of a QA moiety on melphalan allows the molecule to be carried selectively to cartilaginous tissues. As the [(14)C]-QA conjugate is radiolabeled on the chloroethyl alkylating moiety, levels of radioactivity measured in the cartilaginous tissues results from unchanged compound or metabolite having kept the active group. PMID:12643763

Rapp, Maryse; Giraud, Isabelle; Maurizis, Jean-Claude; Galmier, Marie-Josèphe; Madelmont, Jean-Claude

2003-01-01

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

2009-12-15

240

Inactivation of monazomycin-induced voltage-dependent conductance in thin lipid membranes. I. Inactivation produced by long chain quaternary ammonium ions  

PubMed Central

The voltage-dependent conductance induced in thin lipid membranes by monazomycin undergoes inactivation upon the introduction of quaternary ammonium ions (QA) having a long alkyl chain (e.g. dodecyltrimethylammonium [C12]) to the side containing monazomycin. That is, in response to a step of voltage the conductance rises to a peak and then falls to a much lower steady-state value. We demonstrate that the basis of this phenomenon is the ability of QA to pass through the stimulated membrane and bind to the opposite surface. As a consequence, the surface potential on that side becomes more positive, thus reducing the voltage across the membrane proper and turning off the monazomycin-induced conductance. Because the flux of QA through the membrane increases linearly with conductance, we believe that these ions pass through the monazomycin channels. QA permeability increases with alkyl chain length; remarkably, in spite of its much larger size, C12 is about 150 times more permeant than K+. It appears, therefore, that there is a hydrophobic region of the cahnnel that favors the alkyl chain; we propose that this region is formed by the hydrophobic faces of the monazomycin channels in lipid bilayers to QA inactivation of potassium channels in the squid giant azon, and suggest that there may be a common structural feature for the two channels. It is possible that some of the inactivation phenomena in excitable cells may arise from local field changes not measurable by the recording electrodes.

1976-01-01

241

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

242

Study on the effects of electrolytes and solvents in the determination of quaternary ammonium ions by nonaqueous capillary electrophoresis with contactless conductivity detection.  

PubMed

A study on the separation of lipophilic quaternary ammonium cations in NACE coupled with contactless conductivity detection (NACE-C(4)D) is presented. The suitability of different salts dissolved in various organic solvents as running electrolytes in NACE-C(4)D was investigated. A solvent mixture of methanol/acetonitrile at a ratio of 90%:10% v/v showed the best results. Deoxycholic acid sodium salt as BGE was found to provide exceptional high stability with low baseline noise that leads to highest S/N ratios for the target analytes among all BGEs tested. Under the optimum conditions, capillaries with different internal diameters were examined and an id of 50 ?m was found to give best detection sensitivity. The proposed method was validated and showed good linearity in the range from 2.5 to 200 ?M, low limits of detection (0.1-0.7 ?M) and acceptable reproducibility of peak area (intraday RSD 0.1-0.7%, n = 3; interday RSD 5.9-9.4%, n = 3). PMID:23161565

Buglione, Lucia; See, Hong Heng; Hauser, Peter C

2013-01-01

243

Does the wide use of quaternary ammonium compounds enhance the selection and spread of antimicrobial resistance and thus threaten our health?  

PubMed

Quaternary ammonium compounds (QACs) are widely used biocides that possess antimicrobial effect against a broad range of microorganisms. These compounds are used for numerous industrial purposes, water treatment, antifungal treatment in horticulture, as well as in pharmaceutical and everyday consumer products as preserving agents, foam boosters, and detergents. Resistance toward QACs is widespread among a diverse range of microorganisms and is facilitated by several mechanisms such as modifications in the membrane composition, expression of stress response and repair systems, or expression of efflux pump genes. Development of resistance in both pathogenic and nonpathogenic bacteria has been related to application in human medicine and the food industry. QACs in cosmetic products will inevitably come into intimate contact with the skin or mucosal linings in the mouth and thus are likely to add to the selection pressure toward more QAC-resistant microorganisms among the skin or mouth flora. There is increasing evidence of coresistance and cross-resistance between QACs and a range of other clinically important antibiotics and disinfectants. Use of QACs may have driven the fixation and spread of certain resistance cassette collectors (class 1 integrons), currently responsible for a major part of antimicrobial resistance in gram-negative bacteria. More indiscriminate use of QACs such as in cosmetic products may drive the selection of further new genetic elements that will aid in the persistence and spread of antimicrobial resistance and thus in limiting our treatment options for microbial infections. PMID:20370507

Hegstad, Kristin; Langsrud, Solveig; Lunestad, Bjørn Tore; Scheie, Anne Aamdal; Sunde, Marianne; Yazdankhah, Siamak P

2010-06-01

244

Tris(cyclo-hexyl-ammonium) cis-di-chlorido-bis-(oxalato-?2 O 1,O 2)stann-ate(IV) chloride monohydrate  

PubMed Central

The crystal structure of the title compound, (C6H14N)3[Sn(C2O4)2Cl2]Cl·H2O, contains three cyclo­hexyl­ammonium cations, one stannate(IV) dianion, one isolated chloride anion and one lattice water mol­ecule. The cyclo­hexyl­ammonium cations adopt chair conformations. In the complex anion, two bidentate oxalate ligands and two chloride anions in cis positions coordinate octa­hedrally to the central SnIV atom. The cohesion of the mol­ecular entities is ensured by the formation of N—H?O, O—H?O, O—H?Cl and N—H?Cl inter­actions involving cations, anions and the lattice water mol­ecule, giving rise to a layer-like arrangement parallel to (010).

Sarr, Modou; Diallo, Waly; Diasse-Sarr, Aminata; Plasseraud, Laurent; Cattey, Helene

2013-01-01

245

Synthesis and structure characterization of diethyldiallylammonium chloride  

Microsoft Academic Search

The unsaturated quaternary ammonium salt diethyladiallylammonium chloride(DEDAAC) was synthesized in a two-step synthetic\\u000a method. The influences of the adding method of raw materials and temperature on the yields of diethylallylamine (DEAA), and\\u000a drying and temperature on the synthesis of DEDAAC were investigated. The content of in-process product DEAA was determined\\u000a by non-aqueous titration. The structure of product DEDAAC was identified

Li-hua Liu; Zhu-qing Gong; Ya-jie Zheng

2003-01-01

246

An instrument for semi-continuous monitoring of the size-distribution of nitrate, ammonium, sulphate and chloride in aerosol  

NASA Astrophysics Data System (ADS)

An instrument was developed for semi-continuous measurement of the size-distribution of submicron nitrate, ammonium, sulphate and chloride. Novel in the instrumentation is the size-classification, which is realised with a pre-separator that consists of a set of four parallel impactors. The cut-off diameters of the impactors are at 0.18, 0.32, 0.56 and 1.0 ?m. Aerosols smaller than the associated cut-off size pass the respective impactor and arrive in the detector. The manifold with impactors contains two additional lines, one open line and one containing a filter that removes all aerosols. This latter line provides an on-line field-blank. The sample air-flow is automatically switched by wide-bore ball valves to one of the six sampling lines for a period of 20 min; a measuring cycle thus takes 2 h. Down-stream of the pre-separator the sampling and automated on-line analysis of the transmitted aerosol is accomplished with a "MARGA". In this instrument steam condensation is used to grow the aerosol. The droplets formed are collected in a cyclone that drains to wet-chemical analysis systems. A wet-denuder between pre-separator and collector removes interfering gases, like nitric acid and ammonia. This enables artefact-free and thus representative semi-continuous measurement of the size-distribution of the semi-volatile (ammonium) nitrate. The novel MARGA-sizer was first used in a 1 week field-test. After modifications it was then deployed in a monitoring campaign of 2 months in the summer of 2002, at the top level of the meteo-tower of Cabauw in the centre of the Netherlands. The high location, 200 m, was chosen to obtain data on ammonium nitrate that are minimally affected by surface emissions of ammonia. The data coverage over the period was over 60%; failure of the instrumentation was mainly associated with spells of extreme solar heating of the tower and associated high temperatures inside. The average concentration of nitrate was 2.6 ?g m -3, which was very similar to the value interpolated from data in the national network. The mass concentration of submicron nitrate was 2.0 ?g m -3, of which 46% was in particles smaller than 0.32 ?m. To put this in perspective: the concentration of submicron sulphate was similar to that of nitrate, while 53% was in particles smaller than 0.32 ?m. The ion balance showed that the compounds were present as the fully neutralised salts. Quite large diurnal variations were observed for nitrate, with a surprising maximum in the afternoon. The size-distribution of the semi-volatile nitrate was rather constant over a daily cycle.

ten Brink, Harry; Otjes, René; Jongejan, Piet; Slanina, Sjaak

247

The effect of ammonium chloride and urea application on soil bacterial communities closely related to the reductive transformation of pentachlorophenol.  

PubMed

Pentachlorophenol (PCP) is widely distributed in the soil, and nitrogen fertilizer is extensively used in agricultural production. However, studies on the fate of organic contaminants as affected by nitrogen fertilizer application have been rare and superficial. The present study aimed to examine the effect of ammonium chloride (NH4Cl) and urea (CO(NH2)2) application on the reductive transformation of PCP in a paddy soil. The study showed that the addition of low concentrations of NH4Cl/CO(NH2)2 enhanced the transformation of PCP, while the addition of high concentrations of NH4Cl/CO(NH2)2 had the opposite effect. The variations in the abundance of soil microbes in response to NH4Cl/CO(NH2)2 addition showed that both NH4Cl and CO(NH2)2 had inhibitory effects on the growth of dissimilatory iron-reducing bacteria (DIRB) of the genus Comamonas. In contrast, for the genus Shewanella, low concentrations of NH4Cl inhibited growth, and high concentrations of NH4Cl enhanced growth, whereas all concentrations of CO(NH2)2 showed enhancement effects. In addition, consistent patterns of variation were found between the abundances of dechlorinating bacteria in the genus Dehalobacter and PCP transformation rates under NH4Cl/CO(NH2)2 addition. In conclusion, nitrogen application produced variations in the structure of the soil microbial community, especially in the abundance of dissimilatory iron-reducing bacteria and dechlorinating bacteria, which, in turn, affected PCP dechlorination. PMID:24662270

Yu, Huan-Yun; Wang, Yong-Kui; Chen, Peng-Cheng; Li, Fang-Bai; Chen, Man-Jia; Hu, Min

2014-05-15

248

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

249

Application to a cartilage targeting strategy: synthesis and in vivo biodistribution of (14)C-labeled quaternary ammonium-glucosamine conjugates.  

PubMed

As part of a cartilage targeting program based on the affinity of the quaternary ammonium (QA) moiety for cartilage, QA derivatives of D-glucosamine (DG), an antirheumatic drug exhibiting a natural tropism for cartilaginous tissues, were designed and evaluated by pharmacokinetic studies. Two QA-DG conjugates were synthesized and labeled with (14)C by cross-linking the QA entity (trimethylammonium or pyridinium) to [(14)C]DG via an amide bond in a two-step procedure. After intravenous injection to male Sprague-Dawley rats, the two (14)C-labeled conjugates exhibited similar pharmacokinetic profiles, but their behavior clearly differed from that of unconjugated DG in several ways. (i) The tissue distribution for the conjugates was more restricted, with a decreased radioactivity level for whole tissues except for kidney, cartilage, and skin. (ii) The radioactivity concentrated more rapidly and strongly in cartilage for the conjugates than for DG for the short times after injection; on the other hand, 1 h after administration, the radioactivity level in cartilage was higher for DG, this result being consistent with the tropism already observed for this compound. (iii) Both conjugates were eliminated predominantly by the urinary route (85%); the radioactivity level in urine for DG was lower (45% of the injected dose), and significant (14)CO(2) was found in expired air, indicating metabolization and utilization of DG for energy-consuming processes. (iv) Blood and plasma kinetics studies displayed an enterohepatic cycle for DG, whereas for the QA conjugates, a rapid disappearance was observed. (v) HPLC analyses of plasma and urine indicated a low degree of metabolization for the conjugates, most of the radioactivity recovered in urine and plasma corresponding to the unchanged molecule. This study demonstrates that the introduction of the QA moiety on DG modifies its biodistribution and lends it a greater specificity for cartilage, at least for short times after injection. These findings justify further work on QA derivatives of other antirheumatic agents. PMID:10725098

Giraud, I; Rapp, M; Maurizis, J C; Madelmont, J C

2000-01-01

250

21 CFR 878.4015 - Wound dressing with poly (diallyl dimethyl ammonium chloride) (pDADMAC) additive.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Wound dressing with poly (diallyl dimethyl ammonium...Surgical Devices § 878.4015 Wound dressing with poly (diallyl dimethyl ammonium... (a) Identification . A wound dressing with pDADMAC additive is intended...

2010-04-01

251

Synthesis of Quaternary Heterocyclic Salts  

PubMed Central

The microwave synthesis of twenty quaternary ammonium salts is described. The syntheses feature comparable yields to conventional synthetic methods reported in the current literature with reduced reaction times and the absence of solvent or minimal solvent.

Winstead, Angela J.; Nyambura, Grace; Matthews, Rachael; Toney, Deveine; Oyaghire, Stanley

2014-01-01

252

Facile preparation of magnetic 2-hydroxypropyltrimethyl ammonium chloride chitosan/Fe3O4/halloysite nanotubes microspheres for the controlled release of ofloxacin.  

PubMed

Magnetic microspheres, 2-hydroxypropyltrimethyl ammonium chloride chitosan/Fe3O4/halloysite nanotubes/ofloxacin (HACC/Fe3O4/HNTs/OFL), for the controlled release of OFL were prepared by in situ crosslinking with glutaraldehyde in the spray-drying process. The magnetic microspheres were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis and a magnetometer. Various parameters influencing the encapsulation efficiency, drug loading and in vitro controlled release properties of the magnetic microspheres for OFL were also studied. Many stripes were formed and some tubular HNTs could be seen at higher magnification on the surface of the HACC/Fe3O4/HNTs/OFL magnetic microspheres. The magnetic microspheres show superparamagnetic property and fast magnetic response. The encapsulation efficiency and the cumulative release of OFL are closely related to HACC concentration, HNTs contents and crosslinking density. The release of OFL follows the first-order kinetics. PMID:24507359

Wang, Qin; Zhang, Junping; Mu, Bin; Fan, Ling; Wang, Aiqin

2014-02-15

253

Investigations of the ex situ ionic conductivities at 30 degrees C of metal-cation-free quaternary ammonium alkaline anion-exchange membranes in static atmospheres of different relative humidities.  

PubMed

This article presents the first systematic study of the effect of Relative Humidity (RH) on the water content and hydroxide ion conductivity of quaternary ammonium-based Alkaline Anion-Exchange Membranes (AAEMs). These AAEMs have been developed specifically for application in alkaline membrane fuel cells, where conductivities of >0.01 S cm(-1) are mandatory. When fully hydrated, an ETFE-based radiation-grafted AAEM exhibited a hydroxide ion conductivity of 0.030 +/- 0.005 S cm(-1) at 30 degrees C without additional incorporation of metal hydroxide salts; this is contrary to the previous wisdom that anion-exchange membranes are very low in ionic conductivity and represents a significant breakthrough for metal-cation-free alkaline ionomers. Desirably, this AAEM also showed increased dimensional stability on full hydration compared to a Nafion-115 proton-exchange membrane; this dimensional stability is further improved (with no concomitant reduction in ionic conductivity) with a commercial AAEM of similar density but containing additional cross-linking. However, all of the AAEMs evaluated in this study demonstrated unacceptably low conductivities when the humidity of the surrounding static atmospheres was reduced (RH = 33-91%); this highlights the requirement for continued AAEM development for operation in H(2)/air fuel cells with low humidity gas supplies. Preliminary investigations indicate that the activation energies for OH(-) conduction in these quaternary ammonium-based solid polymer electrolytes are typically 2-3 times higher than for H(+) conduction in acidic Nafion-115 at all humidities. PMID:17356755

Varcoe, John R

2007-03-28

254

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

2013-03-20

255

5-Acetyl-4-(3-hy-droxy-phen-yl)-6-methyl-1,2,3,4-tetra-hydro-pyrimidin-2-one-tris-(hy-droxy-meth-yl)ammonium chloride (2/1)  

PubMed Central

The asymmetric unit of the title compound, 2C13H14N2O3·C3H10NO3 +·Cl?, contains two independent mol­ecules (A and B) of the title pyrimidine derivative and one ion-pair of tris­(hy­droxy­meth­yl)ammonium chloride. The pyrimidine ring in each pyrimidine derivative has a half-chair conformation. Its mean plane is inclined to the benzene ring by 87.2?(3)° in mol­ecule A and 85.7?(2)° in mol­ecule B. In the crystal, the pyrimidine derivatives are connected to each other by N—H?O hydrogen bonds, forming chains propagating along the b-axis direction. The chains are linked via O—H—Cl hydrogen bonds, forming corrugated sheets lying parallel to the bc plane. The sheets are linked via C—H?O hydrogen bonds, forming a three-dimensional framework. The tris­(hy­droxy­meth­yl)ammonium chloride mol­ecules are located in the cages of the framework. There are also further C—H?O hydrogen bonds and C—H?? inter­actions present in the three-dimensional framework structure. Both the cation and chloride anion of the tris­(hy­droxy­meth­yl)ammonium chloride ion pair are disordered over two positions, with a refined occupancy ratio of 0.418?(8):0.582?(8) for the cation and 0.71?(4):0.29?(4) for the anion.

Huq, C. A. M. A.; Fouzia, S.; NizamMohideen, M.

2013-01-01

256

The preparation of quaternary ammonium-based ionic liquid containing a cyano group and its properties in a lithium battery electrolyte  

Microsoft Academic Search

A room temperature ionic liquid consisting of N,N,N,N-cyanomethyl trimethyl ammonium (CTMA) cation and bis(trifluoromethane sulfone)imide (TFSI) anion was newly synthesized, and its electrochemical properties were investigated. This ionic liquid has a melting point of 35°C and an order of conductivity of 10?4Scm?1. Lithium deposition\\/dissolution tests in 0.2moldm?3 LiTFSI\\/CTMATFSI electrolytes showed an improved cycle behavior compared with that of a Li

Minato Egashira; Shigeto Okada; Jun-ichi Yamaki; Diego Alejandro Dri; Francesco Bonadies; Bruno Scrosati

2004-01-01

257

Reactivity of Ammonium Chloride\\/Mercuric Chloride Mixtures with Monel Containers. The New Compounds (NH 4) 2(NH 3) x [Ni(NH 3) 2Cl 4] and (NH 4) 5Cl 2[CuCl 2][CuCl 4  

Microsoft Academic Search

Ammonium chloride\\/mercuric chloride mixtures (molar ratio 2:1) react at 350°C with Monel (Cu68Ni32) to yield (NH4)NiCl3 and mercury and copper amalgam, respectively. With larger amounts of (NH4)Cl in the reaction mixture, dark green (NH4)2(NH3)x[Ni(NH3)2Cl4] (x?0.77) (1) is also formed as a main product. Light blue crystals of the mixed-valent copper(I,II) chloride (NH4)5Cl2[CuCl2][CuCl4] (2) were obtained as a minor byproduct from

Gerd Meyer; Peter Nockemann

2001-01-01

258

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

259

Electrodialytic Transport Properties of Anion-Exchange Membranes Prepared from Poly(vinyl alcohol) and Poly(vinyl alcohol-co-methacryloyl aminopropyl trimethyl ammonium chloride)  

PubMed Central

Random-type anion-exchange membranes (AEMs) have been prepared by blending poly(vinyl alcohol) (PVA) and the random copolymer-type polycation, poly(vinyl alcohol-co-methacryloyl aminopropyl trimethyl ammonium chloride) at various molar percentages of anion-exchange groups to vinyl alcohol groups, Cpc, and by cross-linking the PVA chains with glutaraldehyde (GA) solution at various GA concentrations, CGA. The characteristics of the random-type AEMs were compared with blend-type AEMs prepared in our previous study. At equal molar percentages of the anion exchange groups, the water content of the random-type AEMs was lower than that of the blend-type AEMs. The effective charge density of the random-type AEMs increased with increasing Cpc and reached a maximum value. Further, the maximum value of the effective charge density increased with increasing CGA. The maximum value of the effective charge density, 0.42 mol/dm3, was obtained for the random-type AEM with Cpc = 4.2 mol % and CGA = 0.15 vol %. A comparison of the random-type and blend-type AEMs with almost the same Cpc showed that the random-type AEMs had lower membrane resistance than the blend-type ones. The membrane resistance and dynamic transport number of the random-type AEM with Cpc = 6.0 mol % and CGA = 0.15 vol % were 4.8 ? cm2 and 0.83, respectively.

Jikihara, Atsushi; Ohashi, Reina; Kakihana, Yuriko; Higa, Mitsuru; Kobayashi, Kenichi

2012-01-01

260

Effect of C.C.C. [2-(chloroethyl)] trimethyl ammonium chloride on growth and sporulation in Fusarium oxysporum f. udum (butl.) Sn. et H.  

PubMed

In Fusarium oxysporum f. udum sporulation of macroconidia was completely inhibited due to the influence of C.C.C. [2-(Chloroethyl)] trimethyl ammonium chloride). Microconidial proliferation, on the other hand, was adversely affected and with increase in concentration of this compound a parallel and proportional decrease in the amount of microconidia was found. Size of microconidia, too, showed a concomitant decline. Although the size of the chlamydospores was also reduced, a tremendous increase in its population was evident, showing a positive response in favour of C.C.C. addition. Fungal mat accumulation, another important aspect of growth, did not evince any inhibitory pattern, compared to the progressive increase in C.C.C. amoung in younger cultures. In older cultures (15-day old), an initial depressing shock of C.C.C. addition could be seen. However, after stepwise and gradual adjustment to the new environment the same positive response of mycelial growth was discernible, although in a less degree than that of the young cultures. PMID:664938

Prasad, M; Chaudhary, S K

1978-01-01

261

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

PubMed Central

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 CEC. 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 MALDI mass spectrometry.

Augustin, Violaine; Stachowiak, Timothy; Svec, Frantisek; Frechet, Jean M.J.

2009-01-01

262

Analysis of benzalkonium chloride in the effluent from European hospitals by solid-phase extraction and high-performance liquid chromatography with post-column ion-pairing and fluorescence detection  

Microsoft Academic Search

A highly reproducible and specific method for the analysis of the quaternary ammonium compound, benzalkonium chloride, in effluents from European hospitals is presented. Benzalkonium chloride was extracted with end-capped RP-18 solid-phase cartridges and was selectively eluted. The resulting solution was analysed by high-performance liquid chromatography (HPLC). After elution from the analytical column of the HPLC system, 9,10-dimethoxyanthracene-2-sulfonate was added continuously

Klaus Kümmerer; Andreas Eitel; Ulrich Braun; Peter Hubner; Franz Daschner; Georges Mascart; Milena Milandri; Franz Reinthaler; Jan Verhoef

1997-01-01

263

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

264

Phase-Transfer Catalysis: Free-Radical Polymerization of Methyl Methacrylate using K2S2O8Quaternary Ammonium Salt Catalyst System. A Kinetic Study  

Microsoft Academic Search

The kinetics of phase-transfer-agent-assisted free-radical polymerization of methyl methacrylate using K2S2O8 as the water-soluble initiator and triethylbenzylammonium chloride (TEBA) as the phase-transfer catalyst (PTC) was investigated in toluene-water biphase media at 60°C. The effect of varying [MMA], [K2S2O8], [TEBA], [H], the ionic strength of the medium, and the temperature on the rate of polymerization (Rp) was studied. Rp was found

T. Balakrishnan; N. Jayachandramani

1994-01-01

265

Adsorption properties of biologically active derivatives of quaternary ammonium surfactants and their mixtures at aqueous/air interface II. Dynamics of adsorption, micelles dissociation and cytotoxicity of QDLS.  

PubMed

The main aim of our study was analysis of adsorption dynamics of mixtures containing quaternary derivatives of lysosomotropic substance (QDLS). Two types of equimolar mixtures were considered: the ones containing two derivatives of lysosomotropic substances (DMALM-12 and DMGM-12) as well as the catanionic mixtures i.e. the systems containing QDLS and DBSNa. Dynamic surface tension measurements of surfactant mixtures were made. The results suggested that the diffusivity of the mixed system could be treated as the average value of rates of diffusion of individual components, micelles and ion pairs, which are present in the mixtures studied. Moreover, an attempt was made to explain the influence of the presence of micelles in the mixtures on their adsorption dynamics. The compounds examined show interesting biological properties which can be useful, especially for drug delivery in medical treatment. In vitro cytotoxic activities of the mixtures studied towards human cancer cells were evaluated. Most of the mixtures showed a high antiproliferative potential, especially the ones containing DMALM-12. Each cancer cell line used demonstrated different sensitivity to the same dose of the mixtures tested. PMID:24768517

Rojewska, Monika; Prochaska, Krystyna; Olejnik, Anna; Rychlik, Joanna

2014-07-01

266

Inactivation of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE) on various environmental surfaces by mist application of a stabilized chlorine dioxide and quaternary ammonium compound-based disinfectant.  

PubMed

Contaminated environmental surfaces are important reservoirs in the transmission of many human pathogens. Although several options exist for disinfecting contaminated environmental surfaces, few are compatible with use on both hard smooth non-porous (hard) and soft porous surfaces (soft) while still offering significant disinfection of the contaminating organisms. This study evaluated the efficacy of mist application of a stabilized chlorine dioxide and quaternary ammonium compound-based disinfectant (Cryocide20) for inactivation of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE) on various environmental surfaces. MRSA and VRE were applied to hard and soft surfaces (glass, steel, tile, carpet, and cotton fabric), allowed to dry, and exposed to a uniform mist application of the disinfectant solution. After 1 hr of contact time, the residual disinfectant was neutralized, and the bacteria were recovered and enumerated on brain heart infusion (BHI) agar. Reduction of both test bacteria was observed on most of the hard and soft surfaces tested. Log(10) reduction of the organisms tended to be higher on steel, tile, and carpet than glass or cotton. Overall, these results suggest that mist application of Cryocide20 disinfectant may be an effective option for reduction of low levels of infectious bacterial pathogens from contaminated environmental surfaces. PMID:20574884

Callahan, K L; Beck, N K; Duffield, E A; Shin, G; Meschke, J S

2010-09-01

267

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

268

The cytotoxicity of methacryloxylethyl cetyl ammonium chloride, a cationic antibacterial monomer, is related to oxidative stress and the intrinsic mitochondrial apoptotic pathway.  

PubMed

Antibacterial monomers incorporated in dentin bonding systems may have toxic effects on the pulp. Thus, the cytotoxicity of antibacterial monomers and its underlying mechanisms must be elucidated to improve the safety of antibacterial monomer application. The influence of an antibacterial monomer, methacryloxylethyl cetyl ammonium chloride (DMAE-CB), on the vitality of L929 mouse fibroblasts was tested using MTT assay. Cell cycle progression was studied using flow cytometry. Production of intracellular reactive oxygen species (ROS) after DMAE-CB treatment was measured using 2,7-dichlorodihydrofluorescein diacetate staining and flow cytometry analysis. Loss of mitochondrial membrane potential, disturbance of Bcl-2 and Bax expression, as well as release of cytochrome C were also measured using flow cytometry analysis or Western blot to explore the possible involvement of the mitochondrial-related apoptotic pathway. DMAE-CB elicited cell death in a dose-dependent manner and more than 50% of cells were killed after treatment with 30 µM of the monomer. Both necrosis and apoptosis were observed. DMAE-CB also induced G1- and G2-phase arrest. Increased levels of intracellular ROS were observed after 1 h and this overproduction was further enhanced by 6-h treatment with the monomer. DMAE-CB may cause apoptosis by disturbing the expression of Bcl-2 and Bax, reducing the mitochondrial potential and inducing release of cytochrome C. Taken together, these findings suggest that the toxicity of the antibacterial monomer DMAE-CB is associated with ROS production, mitochondrial dysfunction, cell cycle disturbance, and cell apoptosis/necrosis. PMID:22002093

Ma, Sai; Shan, Le-qun; Xiao, Yu-hong; Li, Fang; Huang, Li; Shen, Lijuan; Chen, Ji-hua

2011-11-01

269

Evaluation of reduced susceptibility to quaternary ammonium compounds and bisbiguanides in clinical isolates and laboratory-generated mutants of Staphylococcus aureus.  

PubMed

The MICs and minimum bactericidal concentrations (MBCs) for the biocides benzalkonium chloride and chlorhexidine were determined against 1,602 clinical isolates of Staphylococcus aureus. Both compounds showed unimodal MIC and MBC distributions (2 and 4 or 8 mg/liter, respectively) with no apparent subpopulation with reduced susceptibility. To investigate further, all isolates were screened for qac genes, and 39 of these also had the promoter region of the NorA multidrug-resistant (MDR) efflux pump sequenced. The presence of qacA, qacB, qacC, and qacG genes increased the mode MIC, but not MBC, to benzalkonium chloride, while only qacA and qacB increased the chlorhexidine mode MIC. Isolates with a wild-type norA promoter or mutations in the norA promoter had similar biocide MIC distributions; notably, not all clinical isolates with norA mutations were resistant to fluoroquinolones. In vitro efflux mutants could be readily selected with ethidium bromide and acriflavine. Multiple passages were necessary to select mutants with biocides, but these mutants showed phenotypes comparable to those of mutants selected by dyes. All mutants showed changes in the promoter region of norA, but these were distinct from this region of the clinical isolates. Still, none of the in vitro mutants displayed fitness defects in a killing assay in Galleria mellonella larvae. In conclusion, our data provide an in-depth comparative overview on efflux in S. aureus mutants and clinical isolates, showing also that plasmid-encoded efflux pumps did not affect bactericidal activity of biocides. In addition, current in vitro tests appear not to be suitable for predicting levels of resistance that are clinically relevant. PMID:23669380

Furi, Leonardo; Ciusa, Maria Laura; Knight, Daniel; Di Lorenzo, Valeria; Tocci, Nadia; Cirasola, Daniela; Aragones, Lluis; Coelho, Joana Rosado; Freitas, Ana Teresa; Marchi, Emmanuela; Moce, Laura; Visa, Pilar; Northwood, John Blackman; Viti, Carlo; Borghi, Elisa; Orefici, Graziella; Morrissey, Ian; Oggioni, Marco Rinaldo

2013-08-01

270

Synthesis of a quaternary amine anion exchange resin and study [of] its adsorption behaviour for chromate oxyanions.  

PubMed

Glycidyl methacrylate/N,N'-methylene bis-acrylamide (GMA/MBA) was prepared and allowed to react with tetraethylenepentamine (TEP) to give glycidyl methacrylate amine resin (RPA) followed by treatment with glycidyl trimethylammonium chloride (GTA) to give glycidyl methacrylate resin bearing quaternary ammonium chloride moieties (RQA). Zeta potential measurements showed that RQA particles are positively charged over pH 2-10 indicating the strong basic nature of the quaternary amine sites. The effect of pH on the recovery of chromate by RPA and RQA was examined. The results indicated that RQA is an efficient sorbent for chromate from both acidic and basic media. The repeated use of RQA was tested through stripping the adsorbed chromate using a mixture of 0.05 NaOH and 2 M NaCl in the case of the uptake from acidic media and using 2 M NaCl solution in the case of alkaline solutions. PMID:16682117

Atia, Asem A

2006-09-21

271

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

272

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

273

Quaternary Studies  

NSDL National Science Digital Library

First, 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" (1). Visitors can learn about the importance of quaternary studies as well as find out the latest news and upcoming meetings. At the second website, the University of Wisconsin-Madison describes the current and recent studies dealing with "basic and applied problems in glacial geology, surficial geology, palynology, sedimentology, geologic mapping, hydrogeology, soils, and environmental geology "(2). The website offers abstracts of publications of members of the Department of Geology and Geophysics and the Wisconsin Geological and Natural History Survey along with descriptions of the lab, a shaded relief map of the Wisconsin area, and amusing glacial songs. Next, the Godwin Institute of Quaternary Research (GIQR) presents the University of Cambridge's history in quaternary research and the seven current research groups and four recent research projects (3 ). The website furnishes news from the research groups, a gallery of historical images of the East Anglia excursion, and summaries of the Institute's reference collections. Fourth, the International Union for Quaternary Research (INQUA) discusses quaternary scientists' investigations "to interpret the changing world of the glacial ages and their impact on our planet's surface environments" (4). Researchers can find out about INQUA-funded projects, meetings, and scientific commissions. Next, the Quaternary Research Association explains that it "exists to promote understanding of the Quaternary Period by publishing field guides, technical guides, and an international journal as well as holding field meetings and speaker meetings" (5). Students and researchers can discover employment, research, grant, meetings, and educational opportunities. Sixth, the University of Wales presents its investigations in the Remote Sensing Laboratory, Palaeoecology Laboratory, and the Luminescence Laboratory (6 ). Users can find concise descriptions of individual researchers' successes, abstracts of published papers, and links to conference information. The seventh website illustrates the Alaska Quaternary Center's commitment "to the promotion of interdisciplinary research and the enhancement of interdisciplinary instruction in Quaternary sciences" (7). Users can view images of the field work and learn how to obtain quaternary data from the Geographic Information Network of Alaska (GINA). Lastly, 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 (8). Students and educators can find information on the researchers involved with the program and the necessary course work.

274

Preparation of Butyl Chloride from Butanol and Hydrochloric Acid Using Ionic Liquids as Catalyst * * Supported by the National Natural Science Foundation of China (No.20376004)  

Microsoft Academic Search

The catalytic performance of some quaternary ammonium salts for the liquid phase reaction of butanol and hydrochloric acid at different conditions was studied experimentally and compared with the traditional catalyst (ZnCl2). The organic ammonium catalysts investigated include ionic liquids N-butyl-N-methyl imidazolium fluoborate ([BMIM][BF4]) and N-butyl-N-methylimidazolium chloride ([BMIM]Cl) as well as hydrochloric salts of N-methylimidazol ([HMIM]Cl), pyridine ([HPy]Cl) and triethylamine ([HEt3N]Cl).

Aijun SUN; Yi NIE; Chunxi LI; Zihao WANG

2008-01-01

275

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

276

High performance ammonium nitrate propellant  

NASA Technical Reports Server (NTRS)

A high performance propellant having greatly reduced hydrogen chloride emission is presented. It is comprised of: (1) a minor amount of hydrocarbon binder (10-15%), (2) at least 85% solids including ammonium nitrate as the primary oxidizer (about 40% to 70%), (3) a significant amount (5-25%) powdered metal fuel, such as aluminum, (4) a small amount (5-25%) of ammonium perchlorate as a supplementary oxidizer, and (5) optionally a small amount (0-20%) of a nitramine.

Anderson, F. A. (inventor)

1979-01-01

277

depth measurement temperature measurement pressure measurement conductivity measurement (Salinity measurement TDS measurement) Oxygen Concentration measurement (Oxygen saturation measurement) pH-value measurement Red-ox-potential ORP measurement turbidity measurement (TSS measurement) measurement ion selective electrode (nitrate chloride ammonium potassium calcium sodium fluoride gas ammonia) fluorescence measurements (chlorophyll a cyanobacteria rhodamine ) optical oxygen measurements.  

EPA Pesticide Factsheets

Did you mean: depth measurement temperature measurement pressure measurement conductivity measurement (Salinity measurement TDS measurement) Oxygen Concentration measurement (Oxygen saturation measurement) pH-value measurement Red-ox-potential ORP measurement turbidity measurement (TSS measurement) measurement ion selective electrode (nitrate chloride ammonium potassium calcium sodium fluoride gas ammonia) fluorescence measurements (chlorophyll a cyanobacteria rhodamine ) optical oxygen measurements. ?

278

(2SR,3RS)-Benz-yl[4-chloro-1-(4-chloro-phen-yl)-1-methoxy-carbon-yl-2-but-yl]-ammonium chloride.  

PubMed

In the racemic hydro-chloride salt of the title ester, C(19)H(22)Cl(2)NO(2) (+)·Cl(-), the penta-noic acid chain shows a mixture of trans and gauche orientations to give an overall helical conformation. The dihedral angle between the two aromatic rings is 26.11?(10)°. The charged secondary amine function participates in two N-H?Cl hydrogen bonds. PMID:21201230

Kaupang, Asmund; Bolsønes, Marianne; Gamadeku, Thywill; Hansen, Tore; Hennum, Martin Johanson; Görbitz, Carl Henrik

2008-01-01

279

Synthesis, self-aggregation and biological properties of alkylphosphocholine and alkylphosphohomocholine derivatives of cetyltrimethylammonium bromide, cetylpyridinium bromide, benzalkonium bromide (C16) and benzethonium chloride.  

PubMed

A series of alkylphosphocholine and alkylphosphohomocholine derivatives of cetyltrimethylammonium bromide, cetylpyridinium bromide, benzalkonium bromide (C16) and benzethonium chloride have been synthesized. Their physicochemical properties were also investigated. The critical micelle concentration (cmc), the surface tension value at the cmc (?cmc), and the surface area at the surface saturation per head group (Acmc) were determined by means of surface tension measurements. The prepared compounds exhibit significant cytotoxic, antifungal and antiprotozoal activities. Alkylphosphocholines and alkylphosphohomocholines possess higher antifungal activity against Candida albicans in comparison with quaternary ammonium compounds in general. However, quaternary ammonium compounds exhibit significantly higher activity against human tumor cells and pathogenic free-living amoebae Acanthamoeba lugdunensis and Acanthamoeba quina compared to alkylphosphocholines. The relationship between structure, physicochemical properties and biological activity of the tested compounds is discussed. PMID:23792315

Luká?, Miloš; Mrva, Martin; Garajová, Mária; Mojžišová, Gabriela; Varinská, Lenka; Mojžiš, Ján; Sabol, Marián; Kubincová, Janka; Haragová, Hana; Ondriska, František; Devínsky, Ferdinand

2013-08-01

280

Ammonium and urea removal by Spirulina platensis  

Microsoft Academic Search

Different concentrations either of ammonium chloride or urea were used in batch and fed-batch cultivations of Spirulina platensis to evaluate the possibility of substituting nitrate by cheaper reduced nitrogen sources in wastewaters biotreatment. The\\u000a maximum nitrogen concentration able to sustain the batch growth of this microalga without inhibition was 1.7 mM in both cases.\\u000a Ammonium chloride was limiting for the growth

A. Converti; S. Scapazzoni; A. Lodi; J. C. M. Carvalho

2006-01-01

281

Reactivity of Ammonium Chloride/Mercuric Chloride Mixtures with Monel Containers. The New Compounds (NH 4) 2(NH 3) x[Ni(NH 3) 2Cl 4] and (NH 4) 5Cl 2[CuCl 2][CuCl 4  

NASA Astrophysics Data System (ADS)

Ammonium chloride/mercuric chloride mixtures (molar ratio 2:1) react at 350°C with Monel (Cu68Ni32) to yield (NH 4)NiCl 3 and mercury and copper amalgam, respectively. With larger amounts of (NH 4)Cl in the reaction mixture, dark green (NH 4) 2(NH 3) x[Ni(NH 3) 2Cl 4] ( x?0.77) (1) is also formed as a main product. Light blue crystals of the mixed-valent copper(I,II) chloride (NH 4) 5Cl 2[CuCl 2][CuCl 4] (2) were obtained as a minor byproduct from a 4:1 reaction mixture. The crystal structures were determined from single crystal X-ray data; (1): tetragonal, I4/ mmm, a=770.9(1), c=794.2(2) pm, 190 reflections, R1=0.0263; (2): tetragonal, I4/ mcm, a=874.8(1), c=2329.2(3) pm, 451 reflections, R1=0.0736. In (1) Ni 2+ resides in trans-[Ni(NH 3) 2Cl 4] 2- octahedra, and in (2) copper(I) is linearly two-coordinated in [CuCl 2] - and copper(II) resides in a flattened tetrahedron [CuCl 4] 2- with a tetrahedricity of 89%.

Meyer, Gerd; Nockemann, Peter

2001-12-01

282

Liquid chromatography of hydrocarbonaeous quaternary amines on cyclodextrin bonded silica  

USGS Publications Warehouse

Mixtures of n-alkylbenzyldimethylammonium chloride (ABDAC) were resolved into homologous components by high-performance liquid chromatography (HPLC) with a cyclodextrin-bonded silica stationary phase. With a few exceptions, results from this study are similar to those obtained from traditional reversed-phase HPLC. It was found that the presence of electrolytes in aqueous mobile phases is not a critical factor in determining the success of HPLC separation. Under normal HPLC conditions, a mobile phase consisting of either methanol–water (50:50) or acetonitrile–water (30:70) was employed for obtaining adequate resolution of the quaternary ammonium mixtures. Although the percent organic modifier–water profiles were similar to those in previous studies with these compounds, resolution (R) and selectivity (?) parameters were found to be quite susceptible to changes in the mobile phase solvent composition. The retention behavior of the cationic analytes in the homologous series is consistent with the hydrophobic-interaction concept proposed for the retention mechanism via dominant inclusion complex formation. Several electrolytes were chosen for a study of the counter ion effect on the chromatographic characteristics of ABDAC components. Among the electrolytes examined, the perchlorate ion was found most likely to act as an ion-pairing counter ion for ammonium cations in the HPLC system studied. A correlation study established linear relationships between the chain length of ABDAC and the logarithmic capacity factor (k2). The analytical utility of the HPLC method was demonstrated by the analysis of various unknown mixtures.

Abidi, S. L.

1986-01-01

283

Enrichment of polychlorinated biphenyls from aqueous solutions using fe(3)o(4) grafted multiwalled carbon nanotubes with poly dimethyl diallyl ammonium chloride.  

PubMed

In this paper, Fe(3)O(4) nanoparticles (Fe(3)O(4) NPs) grafted carboxyl groups of multiwalled carbon nanotubes with cationic polyelectrolyte poly (dimethyldiallylammonium chloride) (PDDA) (MWCNTs-COO(-)/PDDA@Fe(3)O(4)), are successfully synthesized and used for the extraction of six kinds of major toxic polychorinated biphenyls (PCBs) from a large volume of water solution. The hydrophilicity of the PDDA cage can enhance the dispersibility of sorbents in water samples, and the superparamagnetism of the Fe(3)O(4) NPs facilitate magnetic separation which directly led to the simplification of the extraction procedure. With the magnetic solid-phase extraction (MSPE) technique based on the MWCNTs-COO(-)/PDDA@Fe(3)O(4) sorbents, it requires only 30 min to extract trace levels of PCBs from 500 mL water samples. When the eluate condensed to 1.0 mL, concentration factors for PCBs became over 500. The spiked recoveries of several real water samples for PCBs were in the range of 73.3-98.9% with relative standard deviations varying from 3.8% to 9.4%, reflecting good accuracy of the method. Therefore, preconcentration of trace level of PCBs by using this MWCNTs-COO(-)/PDDA@Fe(3)O(4) sorbent, which are stable for multiple reuses, from water solution can be performed. PMID:22754371

Zeng, Shaolin; Cao, Yuting; Sang, Weiguo; Li, Tianhua; Gan, Ning; Zheng, Lei

2012-01-01

284

Study of the sensitization of tetradecyl benzyl dimethyl ammonium chloride for the color development reaction between lysine and sodium 1,2-naphthoquinone-4-sulfonate and the determination of lysine in pharmaceutical and biological samples  

NASA Astrophysics Data System (ADS)

A rapid, simple and sensitive method for the determination of lysine (Lys) using sodium 1,2-naphthoquinone-4-sulfonate (NQS) and tetradecyl benzyl dimethyl ammonium chloride (Zeph) is presented in this paper. The method is based on the russety product formed from Lys, NQS and Zeph in a buffer solution of pH 9.60, and the stoichiometric ratio of the product is 1:2:2. Beer's law is obeyed in a range of 0.09-18 ?g ml -1 of Lys at the maximum absorption of 474 nm ( ?474 is 8.1 × 10 5 l mol -1 cm -1). The equation of linear regression is A = 0.40427 + 0.06112 C, with a linearly correlation coefficient of 0.9972. The limit of detection is 0.07 ?g ml -1, R.S.D. 0.8%, and average recovery rate in a range of 98.9-100.1%. This paper further optimizes the determination of Lys compared with the previous methods, and the reaction mechanism is studied intensively. The proposed method has been successfully applied to the determination of Lys in pharmaceutical and biological samples. The common components as nutritional additives in pharmaceuticals and other compounds in biological samples nearly do not interfere with the proposed method.

Li, Quanmin; Zhang, Tiantian

2007-06-01

285

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

286

Method for the Abatement of Hydrogen Chloride.  

National Technical Information Service (NTIS)

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 coll...

S. J. Winston T. R. Thomas

1977-01-01

287

Method for the Abatement of Hydrogen Chloride.  

National Technical Information Service (NTIS)

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 coll...

S. J. Winston T. R. Thomas

1975-01-01

288

(Methyldiphenyl-phospho-ranylidene)-ammonium chloride  

PubMed Central

The title compound, C13H15NP+·Cl?, was obtained by hydrolysis of the N-trimethysilyl derivative of methydiphenyl­imino­phosphine. The dihedral angle between the phenyl rings in the cation is 61.5?(3)°. In the crystal structure, inter­molecular N—H?Cl hydrogen bonds links the two components, forming a centrosymmetric 2 + 2 aggregate.

Valerio-Cardenas, Cintya; Ortiz-Frade, Luis; Grevy M., Jean-Michel

2009-01-01

289

21 CFR 177.1980 - Vinyl chloride-propylene copolymers.  

Code of Federal Regulations, 2010 CFR

...50 percent by weight sodium hydroxide solution are added to prevent loss of chloride from ammonium chloride, if present, and the solution is evaporated to approximately...5 grams of granular sodium peroxide,...

2009-04-01

290

21 CFR 177.1980 - Vinyl chloride-propylene copolymers.  

Code of Federal Regulations, 2010 CFR

...50 percent by weight sodium hydroxide solution are added to prevent loss of chloride from ammonium chloride, if present, and the solution is evaporated to approximately...5 grams of granular sodium peroxide,...

2010-01-01

291

Quaternary and Geomorphology.  

ERIC Educational Resources Information Center

Highlights conferences and meetings of organizations involved with quaternary geology and geomorphology, including International Union of Quaternary Research Conference held in Moscow. The impetus of a revision of "The Quaternary of the United States" resulted from this conference. Includes activities/aims of "Friends of the Pleistocene"…

Andrews, J. T.; Graf, W. L.

1983-01-01

292

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

293

Cetyltrimethyl ammonium bromide assisted hydrothermal growth of hematite hollow cubes  

Microsoft Academic Search

Hematite hollow cubes have been prepared by forced hydrolysis of ferric chloride solutions under hydrothermal conditions. The effects of reaction time, reaction temperature and cetyltrimethyl ammonium bromide on the transformation process from akageneite to hematite were investigated in detail. The products were characterized by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. It is found that cetyltrimethyl ammonium

Wei-Wei Wang; Jia-Liang Yao

2010-01-01

294

Prediction of ammonium salt deposition in hydroprocessing air cooler tubes  

Microsoft Academic Search

Corrosion by wet ammonium salt is one of the main causes to the failure of reactor effluent air cooler (REAC) tubes. Based on a failure case, this paper presents the dynamic process of ammonium chloride (NH4Cl) deposition. A finite element method was used for the numerical simulation of the flow field, temperature field and concentration field to analysis this deposition

Guofu Ou; Haozhe Jin; Haoping Xie; Jing Cao; Jie Qiu

2011-01-01

295

Quaternary Research Association  

NSDL National Science Digital Library

The Quaternary Research Association explains that it "exists to promote understanding of the Quaternary Period by publishing field guides, technical guides, and an international journal as well as holding field meetings and speaker meetings." Students and researchers can discover employment, research, grant, meetings, and educational opportunities.

1969-12-31

296

The role of common urinary constituents in the precipitation of ammonium acid urate.  

PubMed

A high proportion of the inhibitory activity shown by urine toward precipitation of ammonium acid urate is ultrafilterable and most of this can be accounted for by the common, low molecular weight components of urine. The individual inhibitory effects of sodium chloride, sodium sulphate, potassium chloride, calcium chloride, magnesium sulphate, sodium dihydrogen phosphate, sodium pyrophosphate, citric acid, hippuric acid, creatinine and urea upon the precipitation of ammonium acid urate have been quantified in an aqueous test system. PMID:519860

Bowyer, R C; Brockis, J G; McCulloch, R K

1979-12-17

297

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

298

Estimation of bottom ammonium affinity in the New Caledonia lagoon  

NASA Astrophysics Data System (ADS)

Ammonium affinity of New Caledonia lagoon benthic communities was measured during the course of 33 in situ enrichment experiments, in order to estimate the contribution of benthos to ammonium fluxes. Ammonium chloride was injected into enclosures pushed into the sediment, in order to obtain a concentration of 20 22 ?mol l-1 in the enclosed water which approximated the interstitial water content. Ammonium kinetic uptake was then followed for two hours. Grey-sand bottom displayed the highest affinity for ammonium, but white-sand and muddy bottom affinity was of the same order of magnitude. Macrophytes, and microphytes (when macrophytes are absent), account for the bulk of ammonium bottom uptake. As a result, grey-sand bottoms with their dense macrophyte cover represent a sink for water column nitrogen and play a key role in nutrient cycling of the lagoon.

Boucher, G.; Clavier, J.; Garrigue, C.

1994-01-01

299

Bacterial resistance to Quaternary Ammonium Compounds (QAC) disinfectants.  

PubMed

Control of bacterial diseases has, for many years, been dependent on the use of antibiotics. Due to the high levels of efficacy of antibiotics in the past other disease control options have, to a large extent, been neglected. Mankind is now facing an increasing problem with antibiotic resistance. In an effort to retain some antibiotics for human use, there are moves afoot to limit or even ban the use of antibiotics in animal production. The use of antibiotics as growth promoters have been banned in the European Union and the USA. The potential ban on the use of antibiotics to treat diseases in production animals creates a dilemma for man-suffer significant problem with bacterial infection or suffer from a severe shortage of food! There are other options for the control of bacterial diseases. These include vaccine development, bacteriophage therapy, and improved biosecurity. Vaccine development against bacterial pathogens, particularly opportunistic pathogens, is often very challenging, as in many cases the molecular basis of the virulence is not always clearly understood. This is particularly true for Escherichia coli. Biosecurity (disinfection) has been a highly neglected area in disease control. With the ever-increasing problems with antibiotic resistance-the focus should return to improvements in biosecurity. As with antibiotics, bacteria also have mechanisms for resistance to disinfectants. To ensure that we do not replace one set of problems (increasing antibiotic resistance) with another (increasing resistance to disinfectants) we need to fully understand the modes of action of disinfectants and how the bacteria develop resistance to these disinfectants. Molecular studies have been undertaken to relate the presence of QAC resistance genes in bacteria to their levels of sensitivity to different generations of QAC-based products. The mode of action of QAC on bacteria has been studied using NanoSAM technology, where it was revealed that the QAC causes disruption of the bacterial cell wall and leaking of the cytoplasm out of the cells. Our main focus is on the control of bacterial and viral diseases in the poultry industry in a post-antibiotic era, but the principles remain similar for disease control in any veterinary field as well as in human medicine. PMID:24595606

Bragg, Robert; Jansen, Arina; Coetzee, Marisa; van der Westhuizen, Wouter; Boucher, Charlotte

2014-01-01

300

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

301

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

2011-09-29

302

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

303

Quaternary Research Center  

NSDL National Science Digital Library

"The Quaternary Research Center (QRC) fosters interdisciplinary research on the last two million years of the global environment: a time which encompasses massive, abrupt changes of climate, sea level, global biota and ice extent, as well the evolution of humans and the advent of civilization." Divided into six laboratories, the University of Washington's Center studies Cosmogenic Isotopes, Stable Isotopes, Old Quaternary Isotopes, Periglacial environments, quaternary ecology, paleoecology, and remote sensing. Researchers can find a tremendous amount of isotope, carbon dioxide, and chemistry data on the Taylor Dome, a part of the East Antarctic ice sheet. Students and educators can read papers by the center covering topics such as interactions among climate, surface, and tectonics; and glaciations and climate variations in the Pacific Northwest.

304

Contribution of ammonium ions to the lethality and antimetamorphic effects of ammonium perchlorate.  

PubMed

Ammonium perchlorate (AP) is a widespread military waste product in the United States and is a potent thyroid function disruptor in all vertebrates tested thus far. To determine the relative contribution of ammonium ions to the toxicity of AP, we exposed embryonic and larval Xenopus laevis to various concentrations of sodium perchlorate (SP) or ammonium chloride (AC). Ammonium perchlorate was significantly more lethal than SP; 5-d LC50s were 83 and 2,780 mg/L, respectively. To determine whether ammonium ions contribute to the antithyroid effects of AP, we exposed embryonic and larval X. laevis to two sublethal, environmentally relevant concentrations of AP or identical concentrations of AC or SP. At the smaller concentration, only AP delayed metamorphosis and reduced hindlimb growth. Sodium perchlorate and AP, but not AC, prevented metamorphosis and reduced hindlimb growth at the greater concentration. Although AP was slightly more effective in reducing outward manifestations of thyroid disruption, both perchlorate salts, unlike AC, caused profound histopathologic changes in the thyroid. Exposure to the higher concentration of either perchlorate salt produced a feminizing effect, resulting in a skewed sex ratio. We conclude that ammonium ions contribute significantly to the toxicity of AP but not to the direct antithyroid effects of perchlorate. PMID:16629145

Goleman, Wanda L; Carr, James A

2006-04-01

305

AMBIENT AMMONIA AND AMMONIUM AEROSOL ACROSS A REGION OF VARIABLE AMMONIA EMISSION DENSITY  

EPA Science Inventory

The paper presents one year of ambient ammonia (NH3), ammonium (NH4+), hydrochloric acid (HCI), chloride (CI¯), nitric acid (HNO3), nitrate (NO3¯), nitrous acid (HONO), sulfur dioxide (SO2), and sulfate (SO4...

306

Adverse Effect of Ammonium Salts on the Antibacterial Activity of Paraformaldehyde Solutions  

PubMed Central

The antibacterial activity of aqueous solutions of paraformaldehyde in concentrations from 0.1 to 0.4% (w/v) is bacteriostatic rather than bactericidal in the presence or absence of ammonium chloride. The presence of ammonium chloride significantly lengthened the time of exposure to paraformaldehyde necessary for inhibition of growth of the test organism (Staphylococcus aureus FDA 209) when unbuffered solutions were used. Elevation of the pH of the reacting mixture of paraformaldehyde and ammonium chloride by partial buffering lengthened the time of exposure necessary for inhibition of growth of the test organism. Decrease of antibacterial activity was concomitant with the disappearance of paraformaldehyde from the reacting mixture. The reaction of paraformaldehyde with ammonium chloride was rapid at room temperature (25 C) and at pH levels near neutrality. The fate of the reacting paraformaldehyde, including the possibility of the formation of hexamethylenetetramine or methylenimine, is discussed with particular reference to loss of antibacterial activity.

Myers, G. E.; McCready, R. G. L.

1963-01-01

307

Quaternary Alloy Microwave MESFET.  

National Technical Information Service (NTIS)

Liquid phase epitaxial growth techniques have been used to grow quaternary alloys, Ga sub 1-x In sub x P sub 1-y As sub y, on InP substrates, using (100), (111) A and (111) B orientations. Liquidus and solidus data at 660 C have been used to determine dis...

J. W. Harrison S. B. Phatak M. A. Littlejohn G. Kelner H. H. Stadelmaier

1979-01-01

308

Quaternary Faunal Environments  

NSDL National Science Digital Library

Students collect information the environments associated with a list of presently living mammals. Students use FAUNMAP to explore the spatial patterns associated with these living mammals during the late Quaternary. They compare these distributions for living mammals to the distribution patterns for a set of extinct mammals. Students answer a set of questions that provide a basis for a summary report.

Hill, Christopher

309

A novel N-acetophenone cinchona ammonium salts as chiral phase transfer catalysts for the alkylation of Schiff base in water  

Microsoft Academic Search

Novel N-acetophenone cinchona ammonium salts have been successfully synthesized and used as chiral phase transfer catalysts for the asymmetric alkylation of tert-butyl benzophenone Schiff base derivatives in aqueous media at room temperature with the highest ee and yield up to 96 and 98%, respectively. We have also studied the influence of substituted acetophenone groups in quaternary ammonium salts derived from

Xin Wang; Jian Lv; Lei Liu; Yongmei Wang; Yang Wu

2007-01-01

310

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

311

Aerobic biotransformation of n-tetradecylbenzyldimethylammonium chloride by an enriched Pseudomonas spp. community.  

PubMed

The biotransformation of n-tetradecylbenzyldimethylammonium chloride (C(14)BDMA-Cl), a quaternary ammonium compound (QAC), under aerobic conditions by an enriched microbial community growing on benzalkonium chlorides (BACs) was investigated. Biotransformation of C(14)BDMA-Cl commenced with cleavage of the C(alkyl)-N bond and formation of benzyldimethylamine (BDMA). BDMA was further degraded, but in contrast to a previously reported BAC biotransformation pathway, neither benzylmethylamine (BMA) nor benzylamine (BA) was detected as a BDMA biotransformation product. Kinetic assays further confirmed that BMA and BA were not intermediates of C(14)BDMA-Cl transformation by the enriched community. Thus, BDMA is thought to be transformed to dimethylamine and benzoic acid via debenzylation. The biomass-normalized rate of C(14)BDMA-Cl biotransformation was 0.09 ?mol/[mg of volatile suspended solids (VSS)·h]. The Microtox acute toxicity EC(50) value of BDMA was 500 times higher than that of C(14)BDMA-Cl. Thus, the aerobic biotransformation of C(14)BDMA-Cl to BDMA results in substantial toxicity reduction. Phylogenetic analysis of Bacteria diversity indicated that the majority of the sequenced clones (98% of the clone library) belonged to the genus Pseudomonas. PMID:22794799

Tezel, Ulas; Tandukar, Madan; Martinez, Robert J; Sobecky, Patricia A; Pavlostathis, Spyros G

2012-08-21

312

Noncovalent Complexation of Monoamine Neurotransmitters and Related Ammonium Ions by Tetramethoxy Tetraglucosylcalix[4]arene  

NASA Astrophysics Data System (ADS)

The noncovalent complexation of monoamine neurotransmitters and related ammonium and quaternary ammonium ions by a conformationally flexible tetramethoxy glucosylcalix[4]arene was studied by electrospray ionization Fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometry. The glucosylcalixarene exhibited highest binding affinity towards serotonin, norepinephrine, epinephrine, and dopamine. Structural properties of the guests, such as the number, location, and type of hydrogen bonding groups, length of the alkyl spacer between the ammonium head-group and the aromatic ring structure, and the degree of nitrogen substitution affected the complexation. Competition experiments and guest-exchange reactions indicated that the hydroxyl groups of guests participate in intermolecular hydrogen bonding with the glucocalixarene.

Torvinen, Mika; Kalenius, Elina; Sansone, Francesco; Casnati, Alessandro; Jänis, Janne

2012-02-01

313

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

314

Molecular Structure of Ammonium ion  

NSDL National Science Digital Library

The first widespread production of ammonium compounds occurred during the 1890s when ammonium sulfate was produced as a by-product from coke oven gas. Ammonium ion is produced as a product of the reaction of water and ammonia. Often, ammonium salts are isomorphous. They have a similar solubility to potassium and rubidium salts, whose ions are similar in size to ammonium. The ion is most stable in the presence of a large compound with a single negative charge.

2002-09-10

315

Benzylhexadecyldimethylammonium chloride in microemulsions and micelles  

Microsoft Academic Search

Benzylhexadecyldimethylammonium chloride (BHDC) micelles in water are very similar to their cetyltrimethyl ammonium bromide (CTAB) counterparts with respect to (1) nature of the micelle surface and polarity (pyrene and pyrene carboxyaldehyde measurements); (2) micelle aggregation number and size; and (3) nature of photochemical reactions centered on the micelle. NMR data indicate that the benzyl group of BHDC interacts with the

R. McNeil; J. K. Thomas

1981-01-01

316

Chloride Test  

MedlinePLUS

... Formal name: Chloride Related tests: Sodium , Potassium , Bicarbonate , Electrolytes , Comprehensive Metabolic Panel , Basic Metabolic Panel , Blood Gases ... if there is a problem with your body's electrolyte balance or acid-base balance and to monitor ...

317

Cesium Chloride  

MedlinePLUS

... with heart rhythm, seizures, loss of consciousness, and electrolyte (blood chemistry) imbalances after taking cesium chloride. How ... with heart rhythm, seizures, loss of consciousness, and electrolyte imbalances. Cesium appears to take the place of ...

318

Topic in Depth - Quaternary Studies  

NSDL National Science Digital Library

Quaternary Studies examines the geologic period of the Quaternary, the last two million years up to the present day. Glaciers formed and receded; animals evolved and went extinct. Here, visitors can learn all about current research and education initiatives in this field of stratigraphic geology.

2010-09-14

319

Formulation of a Product Containing the Multifunctional Corrosion Inhibitor System DNBM.  

National Technical Information Service (NTIS)

Four quaternary ammonium salt inhibitors-DNBM(dichromate, nitrite, borate, and molybdate)-based on the quaternary ammonium chloride phase-change catalyst Adogen 464 were synthesized by double displacement reactions in the laboratory. The DNBM product in k...

L. J. Bailin

1989-01-01

320

Studies on Ammonium Perchlorate Combustion.  

National Technical Information Service (NTIS)

This publication contains four articles: The effect of aluminum on the combustion of ammonium perchlorate with polyformaldehyde; Kinetics of the high-temperature thermal decomposition of ammonium perchlorate; Causes for anomalies during combustion of ammo...

A. A. Zenin G. B. Manelis A. P. Glazkova L. D. Romodanova

1969-01-01

321

Ammonium inhibition of nitrogenase activity in Herbaspirillum seropedicae  

SciTech Connect

The effect of oxygen, ammonium ion, and amino acids on nitrogenase activity in the root-associated N{sub 2}-fixing bacterium Herbaspirillum seropedicae was investigated in comparison with Azospirillum spp. and Rhodospirillum rubrum. H. seropedicae is microaerophilic, and its optimal dissolved oxygen level is from 0.04 to 0.2 kPa for dinitrogen fixation but higher when it is supplied with fixed nitrogen. No nitrogenase activity was detected when the dissolved O{sub 2} level corresponded to 4.0 kPa. Ammonium, a product of the nitrogenase reaction, reversible inhibited nitrogenase activity when added to derepressed cell cultures. However, the inhibition of nitrogenase activity was only partial even with concentrations of ammonium chloride as high as 20 mM. Amides such as glutamine and asparagine partially inhibited nitrogenase activity, but glutamate did not. Nitrogenase in crude extracts prepared from ammonium-inhibited cells showed activity as high as in extracts from N{sub 2}-fixing cells. The pattern of the dinitrogenase and the dinitrogenase reductase revealed by the immunoblotting technique did not change upon ammonium chloride treatment of cells in vivo. No homologous sequences were detected with the draT-draG probe from Azospirillum lipoferum. There is no clear evidence that ADP-ribosylation of the dinitrogenase reductase is involved in the ammonium inhibition of H. seropedicae. The uncoupler carbonyl cyanide m-chlorophenylhydrazone decreased the intracellular ATP concentration and inhibited the nitrogenase activity of whole cells. The ATP pool was significantly disturbed when cultures were treated with ammonium in vivo.

Fu, H.; Burris, R.H. (Univ. of Wisconsin, Madison (USA))

1989-06-01

322

Quantum realization of some quaternary circuits  

Microsoft Academic Search

We present the design of quaternary quantum version of reversible circuits such as Toffoli gate, modified Fredkin gate, mux, demux, encoder-decoder using linear ion realizable quaternary Muthukrishnan-Stroud gates. Our realization of quaternary Toffoli gate is more efficient than the previous realization and other quaternary circuits are realized for the time in literature.

Mahmud Muntakim Khan; Ayan Kumar Biswas; Shuvro Chowdhury; M. Tanzid; K. M. Mohsin; M. Hasan; A. I. Khan

2008-01-01

323

Quaternary GIS Laboratory  

NSDL National Science Digital Library

This is the home page of the Quaternary Geographic Information System (GIS) Laboratory at the Institute of Arctic and Alpine Research (INSTAAR) at the University of Colorado. The laboratory supports quantitative spatial analysis of glacier, climate, coastal, and other environmental relationships at high latitudes. Users can access a collection of climate animations for the State of Alaska which show seasonal variation in monthly temperature and precipitation. There is also a set of high-resolution imagery and terrain models for Barrow, Alaska, an animation of the land bridge between Asia and North America, an atlas of paleoglaciation for the state, and links to a variety of other projects involving climatology, paleoclimatology, and glacial geomorphology in the Sate of Alaska.

324

Quaternary GIS Laboratory  

NSDL National Science Digital Library

This is the home page of the Quaternary Geographic Information System (GIS) Laboratory at the Institute of Arctic and Alpine Research (INSTAAR) at the University of Colorado. The laboratory supports quantitative spatial analysis of glacier, climate, coastal, and other environmental relationships at high latitudes. Users can access a collection of climate animations for the State of Alaska which show seasonal variation in monthly temperature and precipitation. There is also a set of high-resolution imagery and terrain models for Barrow, Alaska, an animation of the land bridge between Asia and North America, an atlas of paleoglaciation for the state, and links to a variety of other projects involving climatology, paleoclimatology, and glacial geomorphology in the Sate of Alaska.

2007-02-27

325

Ammonium Homeostasis and Human Rhesus Glycoproteins  

Microsoft Academic Search

The brain ammonium production is detoxified by astrocytes, the gut ammonium production is detoxified by hepatic cells, and the renal ammonium production plays a major role in renal acid excretion. As a result of ammonium handling in these organs, the ammonium and pH values are strictly regulated in plasma. Up until recently, it was accepted that mammalian cell transmembrane ammonium

Gabrielle Planelles

2007-01-01

326

Experimental study of directional solidification of aqueous ammonium chloride solution  

NASA Technical Reports Server (NTRS)

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 the mushy layer in all experiments. Plume convection with associated chimneys in the mush occurred in experiments with bottom temperatures as high as +11.0 C. However, when the bottom temperature was raised to +11.9 C, no plume convection was observed, although finger convection continued as usual. A method has been devised to determine the porosity of the mush by computed tomography. Using the mean value of the porosity across the mush layer and the permeability calculated by the Kozeny-Carman relationship, the critical solute Rayleigh number across the mush layer for onset of plume convection was estimated to be between 200 and 250.

Chen, C. F.; Chen, Falin

1991-01-01

327

Hypoxia-selective antitumor agents. 12. Nitrobenzyl quaternary salts as bioreductive prodrugs of the alkylating agent mechlorethamine.  

PubMed

A series of benzene-substituted analogues of the novel hypoxia-selective cytotoxin N,N-bis(2-chloroethyl)-N-methyl-N-(2-nitrobenzyl)ammonium chloride (3a), together with three corresponding tetrahydroisoquinolinium "cyclic" analogues 21a-23a and two naphthalene derivatives (19a and 20a), have been prepared and evaluated for cytotoxicity in cultured mammalian tumor cells under aerobic and hypoxic conditions. The parent compound 3a has a one-electron reduction potential of -358 mV and undergoes reductively-induced fragmentation to release the nitrogen mustard mechlorethamine. The compounds were prepared by halogenation (SOCl2) of the corresponding quaternary diols, which in turn were synthesized from N-methyldiethalnolamine and substituted nitrobenzyl chlorides. The reduction potentials of the benzene-substituted compounds were generally well-predicted by Hammett substituent relationships. All of the compounds were much more toxic toward repair-deficient UV4 cells than the corresponding wild-type AA8 cells, as expected if the active cytotoxic species as a DNA alkylating agent. They were also more toxic toward the human cell lines EMT6 and FME compared to AA8, but the reasons for this are not known. Analogues of 3a substituted in the phenyl ring with electron-donating substituents provided compounds with widely differing selectivities for hypoxic AA8 cells, ranging from no selectivity for the 3-Me compound 9a to 3000-fold (at least as great as that of the parent 3a) for the 4-OMe compound 14a. The naphthalene derivatives 19a and 20a and the tetrahydroisoquinolinium compounds 21a-23a showed no hypoxic selectivity. Selective chemical reduction of 22a and 23a with nickel boride resulted in isolation of the corresponding stable amino derivatives, indicating that reduction of these compounds does not result in fragmentation. The reason(s) for the marked differences in hypoxic selectivity of the nitrobenzyl quaternary mustards is unknown, but may reflect differences in radical chemistry, cell uptake, or sensitivity to enzymatic reduction. PMID:8676343

Tercel, M; Wilson, W R; Anderson, R F; Denny, W A

1996-03-01

328

Cetyltrimethyl ammonium bromide assisted hydrothermal growth of hematite hollow cubes  

SciTech Connect

Hematite hollow cubes have been prepared by forced hydrolysis of ferric chloride solutions under hydrothermal conditions. The effects of reaction time, reaction temperature and cetyltrimethyl ammonium bromide on the transformation process from akageneite to hematite were investigated in detail. The products were characterized by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. It is found that cetyltrimethyl ammonium bromide was a critical factor influencing the phase transformation process of akageneite and the final morphology of the as-prepared products. With cetyltrimethyl ammonium bromide, hematite hollow cubes and porous spheres were obtained. Otherwise only dense cubes were observed even prolonging reaction time or increasing reaction temperature. The mechanism was proposed.

Wang, Wei-Wei, E-mail: weiweiwangsd@yahoo.com.cn [School of Materials Science and Engineering, Shandong University of Technology, 12 Zhang Zhou Road, Zibo, Shandong 255091 (China)] [School of Materials Science and Engineering, Shandong University of Technology, 12 Zhang Zhou Road, Zibo, Shandong 255091 (China); Yao, Jia-Liang [School of Materials Science and Engineering, Shandong University of Technology, 12 Zhang Zhou Road, Zibo, Shandong 255091 (China)] [School of Materials Science and Engineering, Shandong University of Technology, 12 Zhang Zhou Road, Zibo, Shandong 255091 (China)

2010-11-15

329

Hydrothermal synthesis of ammonium illite  

USGS Publications Warehouse

Synthetic gel and glass of illitic composition, natural kaolinite, and mixed-layer illite-smectite were used as starting materials for hydrothermal synthesis of ammonium illite. Ammonium illite was prepared from synthetic gel by hydrothermal treatment at 300??C. The onset of crystallization began within 3 h, and well-crystallized ammonium illite appeared at 24 h. Increasing reaction time (up to four weeks) led to many illite layers per crystal. In the presence of equivalent proportions of potassium and ammonium, the gel was transformed to illite with equimolar contents of K and NH4. In contrast, synthesis using glass under the same conditions resulted in a mixture of mixed-layer ammonium illite-smectite with large expandability and discrete illite. Hydrothermal treatments of the fine fractions of natural kaolinite and illite-smectite produced ammonium illite from kaolinite but the illite-smectite remained unchanged.

Sucha, V.; Elsass, F.; Eberl, D. D.; Kuchta, L'.; Madejova, J.; Gates, W. P.; Komadel, P.

1998-01-01

330

In vivo stability and distribution of (/sup 131/I)iodomethyl trimethylammonium chloride: concise communication  

SciTech Connect

(/sup 131/I)iodomethyl trimethylammonium chloride (I-131 TMA) was prepared by the isotope-exchange reaction of diiodomethane with Na/sup 131/I, followed by reaction with trimethylamine. A specific activity of 20 ..mu..Ci/mg was obtained. Tissue distributions following intravenous injection of I-131 TMA in mice showed that between 10 min and 2 h, the highest accumulations of radioactivity were in the urine, kidney, and heart. The uptake of this compound in the heart was very rapid, and the levels of radioactivity remained fairly high up to 2 h. At 10, 30, 60, and 120 min the heart-to-blood ratios were, respectively, 10.2, 7.7, 8.3, and 9.6. Thyroid uptake of this compound in the rats and analysis of urine samples of the mouse indicated no extensive deiodination of the compound in vivo. These results show that this compound does have potential for use in myocardial imaging. In addition, its stability in vivo makes it very useful for the radiolabeling of compounds containing quaternary ammonium moieties.

Huang, C.C.; Friedman, A.M.; Rayudu, G.V.S.; Clark, P.; Fordham, E.W.

1980-07-01

331

Biochemical characterization of a Pseudomonas fluorescens strain isolated from a benzalkonium chloride solution.  

PubMed

A bacterium isolated as the contaminant of a batch of commercial benzalkonium chloride (BAC) solution (10% (w/v)) stored in a loosely capped bottle in the Department of Pharmacy Shinshu University Hospital was identified as Pseudomonas fluorescens belonging to biotype G of Stanier, et al. The strain was highly resistant to BAC, and the lowest concentration of BAC that inhibited visible growth of the strain as measured on nutrient agar plates was > or = 5000 micrograms/ml. BAC is a typical quaternary ammonium detergent. Thus we examined the tolerable growth concentration of various strains on surfactants. We were able to confirm growth of P. fluorescens of BAC resistance strain (PFRB) in 5% concentration, but the other strains were not able to grow in 0.1% concentration. We investigated the relationship between biotype and resistance to BAC. PFRB and three clinical isolated strains were found to be the same biotype G. However, no apparent correlation was found between the same biotypes and minimum inhibitory concentration (MIC) of disinfectant or growth permissible concentration on surfactants. The strain was unable to decompose BAC, as no growth occurred in the minimum medium containing BAC as the sole source of carbon, nitrogen or both. Our finding caused us to realize that P. fluorescens might also be a contaminant of disinfectants, as we have seen in Pseudomonas cepacia. PMID:8799490

Nagai, K; Ohta, S; Zenda, H; Matsumoto, H; Makino, M

1996-06-01

332

Desorption kinetics of cadmium from soils using M ammonium nitrate and M ammonium chloride  

Microsoft Academic Search

The bioavailability and, hence, potential toxicity of a trace metal ion in the soil depends on its concentration in the soil solution and on the soil's ability to release the trace metal ions from the solid phase to replenish those removed from the soil solution by plants. Voluminous literature is available on the sorption characteristics of heavy metals by soils.

G. S. R. Krishnamurti; P. M. Huang; L. M. Kozak

1999-01-01

333

Ammonium generation during SRAT cycle  

SciTech Connect

During the IDMS noble-metal demonstration runs ammonium nitrate deposition was found in the vessel vent system of the feed preparation area. In the bench-scale experiments of studying the hydrogen generation during the sludge treatment cycle, ammonium ion production was also monitored. It was found that: During a simulation of the DWPF Cold Chemical Runs SRAT cycle no detectable amount of ammonium ions was generated when treating a non-noble-metal containing sludge simulant according to the nitric acid flowsheet. Ammonium ions were generated during the SRAT-SME cycle when treating the noble-metal containing sludge with either formic acid or nitric acid/late-washing PHA. This is due to the reaction between formic acid and nitrate catalyzed by the noble metals in the sludge simulant. Ammonium ion production closely followed the hydrogen evolution from the catalytic decomposition of formic acid. This report summarizes the results of the production of ammonia during the SRAT cycle.

Hsu, C.W.

1992-10-13

334

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

335

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

336

76 FR 70366 - Ammonium Nitrate Security Program  

Federal Register 2010, 2011, 2012, 2013

...NPRM for the Ammonium Nitrate Security Program. The agenda for the public...Department's Ammonium Nitrate Security Program Web site, at http://www.dhs...programs/ammonium-nitrate-security-program.shtm. This...

2011-11-14

337

76 FR 62311 - Ammonium Nitrate Security Program  

Federal Register 2010, 2011, 2012, 2013

...NPRM) for the Ammonium Nitrate Security Program. The agenda for the public...Department's Ammonium Nitrate Security Program Web site in mid-October at http...programs/ammonium-nitrate-security-program.shtm. Each...

2011-10-07

338

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

339

Late Quaternary vegetation - climate feedbacks  

Microsoft Academic Search

Feedbacks between vegetation and other components of the climate system are discussed with respect to their influence on climate dynamics during the late Quaternary, i.e., the last glacial - interglacial cycles. When weighting current understanding based on interpretation of palaeobotanic and palaeoclimatic evidence by numerical climate system models, a number of arguments speak in favour of vegetation dynamics being an

M. Claussen

2009-01-01

340

Anaerobic ammonium oxidation for treatment of ammonium-rich wastewaters  

Microsoft Academic Search

The concept of anaerobic ammonium oxidation (ANAMMOX) is presently of great interest. The functional bacteria belonging to\\u000a the Planctomycete phylum and their metabolism are investigated by microbiologists. Meanwhile, the ANAMMOX is equally valuable\\u000a in treatment of ammonium-rich wastewaters. Related processes including partial nitritation-ANAMMOX and completely autotrophic\\u000a nitrogen removal over nitrite (CANON) have been developed, and lab-scale experiments proved that both

Lei Zhang; Ping Zheng; Chong-jian Tang; Jin Ren-cun

2008-01-01

341

Metabolism of nitrate- and ammonium-nitrogen absorbed from ammonium nitrate and ammonium sulfate in the tobacco plant  

Microsoft Academic Search

In water culture experiments with tobacco plants, ammonium nitrate has been generally used as a nitrogen source. In a comparison among various nitrogen sources for water cultured tobacco, better growth has been obtained with ammonium nitrate than with sodium nitrate and ammonium sulfate (1). It has been shown that both ammonium- and nitrate-nitrogen are simultaneously absorbed by the tobacco plant

Daisuke Yoshida

1966-01-01

342

Rubidium and cesium ion adsorption by an ammonium molybdophosphate–calcium alginate composite adsorbent  

Microsoft Academic Search

A composite spherical adsorbent was prepared with ammonium molybdophosphate (AMP), sodium alginate (NaALG), and calcium chloride. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterize the composite adsorbent. The adsorption of rubidium and cesium ions onto the composite adsorbent in aqueous solutions was investigated comprehensively by varying the initial metal ion concentration, pH, ionic strength, and

Xiushen Ye; Zhijian Wu; Wu Li; Haining Liu; Quan Li; Binju Qing; Min Guo; Fei Ge

2009-01-01

343

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

344

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

2005-11-18

345

Long-term exposure to benzalkonium chloride disinfectants results in change of microbial community structure and increased antimicrobial resistance.  

PubMed

The effect of benzalkonium chlorides (BACs), a widely used class of quaternary ammonium disinfectants, on microbial community structure and antimicrobial resistance was investigated using three aerobic microbial communities: BACs-unexposed (DP, fed a mixture of dextrin/peptone), BACs-exposed (DPB, fed a mixture of dextrin/peptone and BACs), and BACs-enriched (B, fed only BACs). Long-term exposure to BACs reduced community diversity and resulted in the enrichment of BAC-resistant species, predominantly Pseudomonas species. Exposure of the two microbial communities to BACs significantly decreased their susceptibility to BACs as well as three clinically relevant antibiotics (penicillin G, tetracycline, ciprofloxacin). Increased resistance to BACs and penicillin G of the two BACs-exposed communities is predominantly attributed to degradation or transformation of these compounds, whereas resistance to tetracycline and ciprofloxacin is largely due to the activity of efflux pumps. Quantification of several key multidrug resistance genes showed a much higher number of copies of these genes in the DPB and B microbial communities compared to the DP community. Collectively, our findings indicate that exposure of a microbial community to BACs results in increased antibiotic resistance, which has important implications for both human and environmental health. PMID:23924280

Tandukar, Madan; Oh, Seungdae; Tezel, Ulas; Konstantinidis, Konstantinos T; Pavlostathis, Spyros G

2013-09-01

346

Quaternary polymethacrylate-magnesium aluminum silicate films: molecular interactions, mechanical properties and tackiness.  

PubMed

The aim of this study was to investigate the impact of the addition of magnesium aluminum silicate (MAS), a natural clay, on the properties of polymeric films based on quaternary polymethacrylates (QPMs). Two commercially available aqueous QPM dispersions were studied: Eudragit(®) RS 30D and Eudragit(®) RL 30D (the dry copolymers containing 5 and 10% quaternary ammonium groups, respectively). The composite QPM-MAS films were prepared by casting. Importantly, QPM interacted with MAS and formed small flocculates prior to film formation. Continuous films were obtained up to MAS contents of 19% (referred to the QPM dry mass). ATR-FTIR and PXRD revealed that the positively charged quaternary ammonium groups of QPM interacted with negatively charged SiO(-) groups of MAS, creating nanocomposite materials. This interaction led to improved thermal stability of the composite films. The puncture strength and elongation at break of dry systems decreased with increasing MAS content. In contrast, the puncture strength of the wet QPM-MAS films (upon exposure to acidic or neutral media) increased with increasing MAS content. Furthermore, incorporation of MAS into QPM films significantly decreased the latter's tackiness in the dry and wet state. These findings suggest that nanocomposite formation between QPM and MAS in the systems can enhance the strength of wet films and decrease their tackiness. Thus, MAS offers an interesting potential as novel anti-tacking agent for QPM coatings. PMID:24144950

Rongthong, Thitiphorn; Sungthongjeen, Srisagul; Siepmann, Juergen; Pongjanyakul, Thaned

2013-12-15

347

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

348

Anaerobic ammonium oxidation for treatment of ammonium-rich wastewaters*  

PubMed Central

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.

Zhang, Lei; Zheng, Ping; Tang, Chong-jian; Jin, Ren-cun

2008-01-01

349

Antimicrobial and inhibitory enzyme activity of N-(benzyl) and quaternary N-(benzyl) chitosan derivatives on plant pathogens.  

PubMed

Chemical modification of a biopolymer chitosan by introducing quaternary ammonium moieties into the polymer backbone enhances its antimicrobial activity. In the present study, a series of quaternary N-(benzyl) chitosan derivatives were synthesized and characterized by (1)H-NMR, FT-IR and UV spectroscopic techniques. The antimicrobial activity against crop-threatening bacteria Agrobacterium tumefaciens and Erwinia carotovora and fungi Botrytis cinerea, Botryodiplodia theobromae, Fusarium oxysporum and Phytophthora infestans were evaluated. The results proved that the grafting of benzyl moiety or quaternization of the derivatives onto chitosan molecule was successful in inhibiting the microbial growth. Moreover, increase water-solubility of the compounds by quaternization significantly increased the activity against bacteria and fungi. Exocellular enzymes including polygalacturonase (PGase), pectin-lyase (PLase), polyphenol oxidase (PPOase) and cellulase were also affected at 1000mg/L. These compounds especially quaternary-based chitosan derivatives that have good inhibitory effect should be potentially used as antimicrobial agents in crop protection. PMID:25037402

Badawy, Mohamed E I; Rabea, Entsar I; Taktak, Nehad E M

2014-10-13

350

Mucoadhesive nanoparticles made of thiolated quaternary chitosan crosslinked with hyaluronan.  

PubMed

Mucoadhesive polymeric nanoparticles intended for drug transport across the gastrointestinal mucosa were prepared from quaternary ammonium-chitosan conjugates synthesised from reduced-MW chitosan (32 kDa). Conjugates contained pendant moieties of 2-4 adjacent diethyl-dimethylene-ammonium groups substituted on repeating units (26-55%). Conjugates were thiolated via amide bonds with thioglycolic acid to yield products with thiol content in the 35-87 ?mol/g range. Nanoparticles with mean size in the 270-370 nm range and positive zeta-potential (+3.7 to +12.5 mV) resulted from ionotropic gelation of the thiolated conjugates with de-polymerised hyaluronic acid (470 kDa). The nanoparticles were fairly stable in size and thiol content and showed a significant mucoadhesivity, matching and even exceeding that of the constituent polymers. Nanoparticles were internalised by endothelial progenitor cells in direct relation to their surface charge intensity. Nanoparticle uptake significantly improved cell viability and resistance to oxidation. The lyophilised nanoparticles were re-dispersible and could make a manageable formulation for oral use. PMID:23218262

Zambito, Ylenia; Felice, Francesca; Fabiano, Angela; Di Stefano, Rossella; Di Colo, Giacomo

2013-01-30

351

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

352

Clinical pharmacokinetics of trospium chloride.  

PubMed

Trospium chloride, a quaternary amine with anticholinergic properties, is used for the treatment of overactive bladder with symptoms of urge urinary incontinence, urgency and urinary frequency. The pharmacokinetics of trospium chloride have been investigated in healthy volunteers, in patients with renal and hepatic impairment, and in those with symptoms of overactive bladder, after oral, intravenous and intravesical administration. After oral administration, absorption of the hydrophilic trospium chloride is slow and incomplete. Peak plasma concentrations (Cmax) of approximately 4 ng/mL are reached 4-5 hours after administration of a 20 mg immediate-release preparation. The mean bioavailability is approximately 10% and decreases by concomitant food intake (to a mean of 26% of the fasting area under the plasma concentration-time curve [AUC]). Trospium chloride displays dose proportional increases in AUC and Cmax after a single dose within the clinically relevant dose range (20-60 mg). The mean volume of distribution is approximately 350-800 L. The drug is minimally (mean approximately 10%) metabolised to spiroalcohol by hydrolysis, is 50% plasma protein bound and does not cross the blood-brain barrier. Urinary excretion of the parent compound plays a major role in the disposition of the drug, with a mean renal clearance of 29 L/h (accounting for approximately 70% of total clearance) and a mean elimination half-life ranging from 10 to 20 hours. Elimination of the drug is slowed in patients with renal insufficiency, and population pharmacokinetic modelling has demonstrated that drug clearance is correlated with serum creatinine concentration. Thus, dose reduction is needed in patients with severe renal impairment (i.e. creatinine clearance < 30 mL/min). To date, no clinically relevant pharmacokinetic drug-drug interactions have been identified; the drug does not bind to any of the drug metabolising cytochrome P450 enzymes. The pharmacokinetics of the drug are compatible with twice-daily administration. A once-daily schedule may also be appropriate, but this regimen needs formal clinical evaluation. PMID:15966754

Doroshyenko, Oxana; Jetter, Alexander; Odenthal, Karl P; Fuhr, Uwe

2005-01-01

353

Adaptations in urea ammonium excretion in metabolic acidosis in the rat: a reinterpretation.  

PubMed

1. The effects of oral hydrochloric acid, ammonium chloride, sodium bicarbonate and ammonium bicarbonate on urea and ammonium excretion in rats on a constant diet were studied. 2. Hydrochloric acid acidosis significantly reduced urea excretion in the rat, with an equimolar increase in NH+4 excretion and no change in their sum. In ammonium chloride acidosis, most of the additional nitrogen intake is excreted as NH+4 and a small percentage as urea. The converse holds true after administration of ammonium bicarbonate. The physiological significance of this is discussed. 3. The shift in nitrogen excretion from urea to NH+4 in acidosis is interpreted on the basis of bicarbonate production and utilization. Urea formation utilizes HCO-3. For amino acid sources, this utilization is offset by the metabolism of the carbon skeleton, which gives rise to HCO-3. When waste nitrogen is excreted as NH+4, no bicarbonate is utilized and the new HCO-3, generated by the carbon skeleton, hels to maintain hydrogen ion homeostasis. PMID:1056282

Oliver, J; Bourke, E

1975-06-01

354

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

355

Glycine methyl ester hydro-chloride.  

PubMed

THE TITLE COMPOUND [SYSTEMATIC NAME: (methoxy-carbonyl-meth-yl)ammonium chloride], crystallizes as a salt, C(3)H(8)NO(2) (+)·Cl(-), with the charged species inter-acting mutually via strong and highly directional N(+)-H?Cl(-) hydrogen bonds which lead to the formation of a supra-molecular tape running parallel to the c axis. Tapes close pack in the solid state mediated by multipoint recognition synthons based on weak C-H?O inter-actions and van der Waals contacts between adjacent methyl groups. PMID:21583646

Vilela, Sérgio M F; Almeida Paz, Filipe A; Tomé, João P C; de Zea Bermudez, Verónica; Cavaleiro, José A S; Rocha, João

2009-01-01

356

Cyclo-hexyl-ammonium nitrate  

PubMed Central

In the title salt, C6H14N+·NO3 ?, the cyclo­hexyl ring adopts a chair conformation. The ammonium group occupies an equatorial position and the crystal struture is stabilized by inter­molecular N—H?O hydrogen-bonding inter­actions, resulting in a three-dimensional network.

Bagabas, Abdulaziz A.; Aboud, Mohamed F. A.; Shemsi, Ahsan M.; Addurihem, Emad S.; Al-Othman, Zeid A.; Chidan Kumar, C. S.; Fun, Hoong-Kun

2014-01-01

357

Cyclo-hexyl-ammonium nitrate.  

PubMed

In the title salt, C6H14N(+)·NO3 (-), the cyclo-hexyl ring adopts a chair conformation. The ammonium group occupies an equatorial position and the crystal struture is stabilized by inter-molecular N-H?O hydrogen-bonding inter-actions, resulting in a three-dimensional network. PMID:24764971

Bagabas, Abdulaziz A; Aboud, Mohamed F A; Shemsi, Ahsan M; Addurihem, Emad S; Al-Othman, Zeid A; Chidan Kumar, C S; Fun, Hoong-Kun

2014-03-01

358

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

359

Chloride - urine test  

MedlinePLUS

The urine chloride test measures the amount of chloride in urine. ... After you provide a urine sample, it is tested in the lab. If needed, the health care provider may ask you to collect your urine ...

360

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 ...

361

Application of the rough sets theory in structure activity relationship of antielectrostatic ammonium compounds.  

PubMed

The relationships between the chemical structure and the antielectrostatic effect of 112 ammonium compounds were analysed using the method of rough sets. The antielectrostatic activity was determined by measurements of the maximum voltage induced. Using the rough sets approach the smallest set of condition attributes significant for high quality of classification has been found. The resulting decision rules describe relations between the structure and the antielectrostatic properties of ammonium chlorides in terms of significant condition attributes. This may be helpful in predicting the structures of the new antielectrostatic compounds to be synthesized. PMID:13678321

Krysi?ski, Jerzy; Skrzypczak, Andrzej; Demski, Grzegorz

2003-01-01

362

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

2013-11-01

363

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

364

21 CFR 184.1137 - Ammonium carbonate.  

Code of Federal Regulations, 2013 CFR

...NH4 )2 CO3 , CAS Reg. No. 8000-73-5) 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...

2013-04-01

365

Extraction of urea and ammonium ion  

NASA Technical Reports Server (NTRS)

Water purification system keeps urea and ammonium ion concentration below toxic limits in recirculated water of closed loop aquatic habitat. Urea is first converted to ammonium ions and carbon dioxide by enzygmatic action. Ammonium ions are removed by ion exchange. Bioburden is controlled by filtration through 0.45 micron millipore filters.

Anselmi, R. T.; Husted, R. R.; Schulz, J. R.

1977-01-01

366

Influence of Ammonium Salts and Cane Molasses on Growth of Alcaligenes eutrophus and Production of Polyhydroxybutyrate  

PubMed Central

The production of polyhydroxybutyrate (PHB) by Alcaligenes eutrophus DSM 545 was studied in a synthetic medium with 3% glucose at pH 7.0 supplemented with several ammonium substrates and cane molasses. Growth was measured by dry cell weight, and the PHB content was measured by gas chromatography. The effects of ammonium sources such as sulfate, nitrate, phosphate, and chloride salts and those of different ammonium sulfate concentrations were evaluated. The best growth and PHB production were obtained with ammonium sulfate; however, NH(inf4)(sup+) concentrations between 0.5 and 1.5 g/liter showed no significant difference. Ammonium sulfate was therefore used as the sole source of NH(inf4)(sup+) for experiments with cane molasses as the growth activator. Optimal growth and PHB production were obtained with 0.3% molasses. However, the yields of biomass (39 to 48%) and PHB (17 to 26%) varied significantly among the different ammonium substrates and cane molasses concentrations.

Beaulieu, M.; Beaulieu, Y.; Melinard, J.; Pandian, S.; Goulet, J.

1995-01-01

367

Phase diagram of ammonium nitrate  

NASA Astrophysics Data System (ADS)

Ammonium Nitrate (AN) has often subjected to uses in improvised explosive devices, due to its wide availability as a fertilizer and its capability of becoming explosive with slight additions of organic and inorganic compounds. Yet, the origin of enhanced energetic properties of impure AN (or AN mixtures) is neither chemically unique nor well understood -resulting in rather catastrophic disasters in the past1 and thereby a significant burden on safety in using ammonium nitrates even today. To remedy this situation, we have carried out an extensive study to investigate the phase stability of AN at high pressure and temperature, using diamond anvil cells and micro-Raman spectroscopy. The present results confirm the recently proposed phase IV-to-IV' transition above 17 GPa2 and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400 °C.

Dunuwille, M.; Yoo, C. S.

2014-05-01

368

Genetic characterization of plasmid-associated benzalkonium chloride resistance determinants in a Listeria monocytogenes strain from the 1998-1999 outbreak.  

PubMed

Quaternary ammonium compounds such as benzalkonium chloride (BC) are widely used as disinfectants in both food processing and medical environments. BC-resistant strains of Listeria monocytogenes have been implicated in multistate outbreaks of listeriosis and have been frequently isolated from food processing plants. However, the genetic basis for BC resistance in L. monocytogenes remains poorly understood. In this study, we have characterized a plasmid (pLM80)-associated BC resistance cassette in L. monocytogenes H7550, a strain implicated in the 1998-1999 multistate outbreak involving contaminated hot dogs. The BC resistance cassette (bcrABC) restored resistance to BC (MIC, 40 ?g/ml) in a plasmid-cured derivative of H7550. All three genes of the cassette were essential for imparting BC resistance. The transcription of H7550 BC resistance genes was increased under sublethal (10 ?g/ml) BC exposure and was higher at reduced temperatures (4, 8, or 25°C) than at 37°C. The level of transcription was higher at 10 ?g/ml than at 20 or 40 ?g/ml. In silico analysis suggested that the BC resistance cassette was harbored by an IS1216 composite transposon along with other genes whose functions are yet to be determined. The findings from this study will further our understanding of the adaptations of this organism to disinfectants such as BC and may contribute to the elucidation of possible BC resistance dissemination in L. monocytogenes. PMID:20971860

Elhanafi, Driss; Dutta, Vikrant; Kathariou, Sophia

2010-12-01

369

Genetic Characterization of Plasmid-Associated Benzalkonium Chloride Resistance Determinants in a Listeria monocytogenes Strain from the 1998-1999 Outbreak ?  

PubMed Central

Quaternary ammonium compounds such as benzalkonium chloride (BC) are widely used as disinfectants in both food processing and medical environments. BC-resistant strains of Listeria monocytogenes have been implicated in multistate outbreaks of listeriosis and have been frequently isolated from food processing plants. However, the genetic basis for BC resistance in L. monocytogenes remains poorly understood. In this study, we have characterized a plasmid (pLM80)-associated BC resistance cassette in L. monocytogenes H7550, a strain implicated in the 1998-1999 multistate outbreak involving contaminated hot dogs. The BC resistance cassette (bcrABC) restored resistance to BC (MIC, 40 ?g/ml) in a plasmid-cured derivative of H7550. All three genes of the cassette were essential for imparting BC resistance. The transcription of H7550 BC resistance genes was increased under sublethal (10 ?g/ml) BC exposure and was higher at reduced temperatures (4, 8, or 25°C) than at 37°C. The level of transcription was higher at 10 ?g/ml than at 20 or 40 ?g/ml. In silico analysis suggested that the BC resistance cassette was harbored by an IS1216 composite transposon along with other genes whose functions are yet to be determined. The findings from this study will further our understanding of the adaptations of this organism to disinfectants such as BC and may contribute to the elucidation of possible BC resistance dissemination in L. monocytogenes.

Elhanafi, Driss; Dutta, Vikrant; Kathariou, Sophia

2010-01-01

370

Ammonium Toxicity and Potassium Limitation in Yeast  

PubMed Central

DNA microarray analysis of gene expression in steady-state chemostat cultures limited for potassium revealed a surprising connection between potassium and ammonium: potassium limits growth only when ammonium is the nitrogen source. Under potassium limitation, ammonium appears to be toxic for Saccharomyces cerevisiae. This ammonium toxicity, which appears to occur by leakage of ammonium through potassium channels, is recapitulated under high-potassium conditions by over-expression of ammonium transporters. Although ammonium toxicity is well established in metazoans, it has never been reported for yeast. To characterize the response to ammonium toxicity, we examined the filtrates of these cultures for compounds whose excretion might serve to detoxify the ammonium (such as urea in mammals). Using liquid chromatography–tandem mass spectrometry to assay for a wide array of metabolites, we detected excreted amino acids. The amounts of amino acids excreted increased in relation to the severity of growth impairment by ammonium, suggesting that amino acid excretion is used by yeast for ammonium detoxification.

Hess, David C; Lu, Wenyun; Rabinowitz, Joshua D; Botstein, David

2006-01-01

371

CHLORIDEDETERMINATION IN HIGH IONIC STRENGTH SOLUTION OF AMMONIUM ACETATE USING NEGATIVE ION ELECTRON SPRAY IONIZATION (HPLC/MS)  

EPA Science Inventory

A precise ion chromatography method has been developed for the determination of chloride in high ionic strength ammonium acetate solutions (10-5 M-5 M) using sodium carbonate/sodium bicarbonate as eluent. Negative ion electrospray ionization (ESI) mass spectrometry was used for q...

372

Influence of Quaternary Ammonium on Sorption of Selected Metal Cations onto Clinoptilolite Zeolite  

Microsoft Academic Search

have permanent negative charges on their surfaces, en- abling them to be modified by cationic surfactants. Such Clay minerals and zeolites have large cation exchange capacities, modification results in a significant increase in total which enable them to be modified by cationic surfactant to enhance their sorption of organic and anionic contaminants. In this study, the organic carbon content of

Zhaohui Li; Daniel Alessi; Lori Allen

2002-01-01

373

Synthesis and properties of side chain liquid crystalline ionomers containing quaternary ammonium salt groups  

Microsoft Academic Search

New thermotropic side chain liquid crystalline ionomers (LCIs), containing 4-(4-allyloxybenzyloxy)-4?-alkoxybiphenyl (IM) as mesogenic unit and allyltriethylammonium bromide (ATAB) as non-mesogenic unit, were synthesized by graft copolymerization upon polymethylhydrosiloxane. The chemical structures of the polymers were confirmed by IR spectroscopy. Differential scanning calorimetry (DSC) was used to measure the thermal properties of these polymers; the mesogenic properties were characterized by polarizing

Bin Tong; Yan Yu; Rongji Dai; Yulin Deng

2004-01-01

374

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

375

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

376

The Role of Molecular Parameters of Quaternary Ammonium Salts in Their Antigibberelin Activity  

Microsoft Academic Search

The role of the molecular parameters of phytoregulators in their growth-regulation activity, with rare exceptions, has not been studied by the method QSAR thus far. It has been found that the lipophilc properties of N-(2-phenoxyethyl)-pyridine bromides substituted at position 2, 3, or 4 of the phenyl group of the molecule exert an effect on the retardant properties of the compounds

R. G. Gafurov; V. Yu. Grigoriev; A. N. Proshin; V. G. Chistyakov; I. V. Martynov; N. S. Zefirov

2004-01-01

377

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

Microsoft Academic Search

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

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

2008-01-01

378

The Development of Dry-RO Membranes from Cellulosic and Noncellulosic Polymers Bearing Quaternary Ammonium Groups.  

National Technical Information Service (NTIS)

Studies were carried out on reverse osmosis (RO) membranes prepared from both cellulosic and noncellulosic materials. For cellulosic membranes produced from quarternized cellulose triesters (QCTE), a successful resolution was achieved to the problems of t...

R. E. Kesting

1982-01-01

379

Quaternary ammonium functionalized clay film electrodes modified with polyphenol oxidase for the sensitive detection of catechol.  

PubMed

Naturally occurring Cameroonian smectite clay has been grafted with trimethylpropylammonium (TMPA) groups and the resulting organoclay has been deposited onto a glassy carbon electrode surface as a suitable immobilization matrix for polyphenol oxidase (PPO). High sensitivity of the electrochemical device to catechol biosensing can be achieved when the enzyme was impregnated within the organoclay film subsequent to its deposition due to favorable electrostatic interaction between PPO and the TMPA-clay layer. The bioelectrode preparation method was also compatible with the use of a mediator (i.e., ferrocene) and the best performance was obtained with a three-layer configuration made of glassy carbon coated with a first layer of ferrocene (Fc), which was then covered with the PPO-impregnated TMPA-clay layer, and finally overcoated with an enzyme-free TMPA-clay film acting as a protecting overlayer to avoid leaching of the biomolecule in solution. The electrochemical behavior of the modified film electrodes was first characterized by cyclic voltammetry and, then, they were evaluated for the amperometric biosensing of the model analyte catechol in batch conditions and in flow injection analysis. Various experimental parameters likely to influence the biosensor response have been investigated, including the electrode preparation mode (composition configuration, thickness), the usefulness of a mediator, the operating potential and pH of the medium, as well as the advantageous features of the TMPA-clay in comparison to related film electrodes based on non-functionalized clays. The organoclay was found to provide a favorable environment to enzyme activity and the multilayer configuration of the film electrode to provide a biosensor with good characteristics, such as an extended linear range for catechol detection (2 x 10(-8) to 1.2 x 10(-5)M) and a detection limit in the nanomolar range (9 x 10(-9)M). PMID:17537626

Mbouguen, Justin Kemmegne; Ngameni, Emmanuel; Walcarius, Alain

2007-09-30

380

Ammonium detection by formation of colored zebra-bands in a detecting tube.  

PubMed

Ammonium ion was colorized by means of a diazo coupling reaction with 2-phenylphenol, where the color development reaction was conducted within 3min by using boric acid as a catalyst. The resulting colored solution (0.5ml) was supplied by suction to a detecting tube consisting of a nonwoven fabric test strip (2mm wide, 1mm thick, 150mm long) impregnated with benzylcetyldimethylammonium chloride in a stripe pattern and enclosed in a heat-shrinkable tube. When the colored solution was supplied to the detecting tube, blue zebra-bands formed, and the ammonium concentration was determined by counting the number of zebra-bands. The detection range was 1-20mg-Nl(-1). Ammonium ion in actual domestic wastewater samples was successfully detected by means of this method. PMID:20441924

Hori, Tatsuaki; Niki, Keizou; Kiso, Yoshiaki; Oguchi, Tatsuo; Kamimoto, Yuki; Yamada, Toshiro; Nagai, Masahiro

2010-06-15

381

Construction of Quaternary Stereogenic Carbon Centers through Copper-Catalyzed Enantioselective Allylic Cross-Coupling with Alkylboranes.  

PubMed

A combination of an in situ generated chiral Cu(I) /DTBM-MeO-BIPHEP catalyst system and EtOK enabled the enantioselective SN 2'-type allylic cross-coupling between alkylborane reagents and ?,?-disubstituted primary allyl chlorides with enantiocontrol at a useful level. The reaction generates a stereogenic quaternary carbon center having three sp(3) -alkyl groups and a vinyl group. This protocol allowed the use of terminal alkenes as nucleophile precursors, thus representing a formal reductive allylic cross-coupling of terminal alkenes. A reaction pathway involving addition/elimination of a neutral alkylcopper(I) species with the allyl chloride substrate is proposed. PMID:24668885

Hojoh, Kentaro; Shido, Yoshinori; Ohmiya, Hirohisa; Sawamura, Masaya

2014-05-01

382

Ultrasonic relaxation studies of ternary and quaternary systems containing 2-butoxyethanol, water, decane, and cetyltrimethylammonium bromide  

SciTech Connect

Ultrasonic absorption measurements have been made in ternary microemulsions composed of oil (decane, DEC)-cosurfactant (2-butoxyethanol, BE)-water and quaternary microemulsions of oil (DEC)-cosurfactant (BE)-surfactant (cetyltrimethylammonium bromide, C/sub 16/TAB)-water in order to study the exchange processes of BE between the bulk phase and the large aggregates present in these systems. The studies were done in the frequency range 5-210 MHz and at temperatures between 25 and 45/degrees/C. The effect of salt (sodium chloride and calcium chloride) on the ultrasonic absorption parameters was also studied in the quaternary systems. The results of these studies show that there are two relaxation processes which are located at /approximately/10 and /approximately/60 MHz for the majority of systems investigated. In the ternary systems, both relaxation frequencies are observed to be independent of decane concentration up to a specific mole percent and then they gradually decrease with increasing concentration of oil until phase separation occurs. In the quaternary systems, the higher relaxation frequency decreases while the lower one is invariant with increasing concentration of decane. The salts do not appear to affect, significantly, the ultrasonic parameters for the quaternary systems. The temperature dependence of the relaxation frequencies in ternary systems was analyzed to give an estimate of the activation enthalpies for the relaxation processes. Values of 15-25 and 13-17 kJ mol/sup -1/ were obtained for the low- and high-frequency relaxation processes, respectively. Photon correlation spectroscopy (PCS) measurements were made in an attempt to obtain additional information on the nature and size of the aggregates present.

Kato, S.; Jobe, D.; Rao, N.P.; Ho, C.H.; Verrall, R.E.

1988-07-14

383

Possibility of safe processing of ammonium nitrate solutions with ammonium formate impurity  

SciTech Connect

Results are presented from research aimed at the development of a method for effective utilization of production wastes consisting of ammonium nitrate solutions with comparatively low concentrations, containing ammonium formate as an impurity. From these data it can be seen that with increasing content of ammonium formate, there is a trend toward a higher level of explosive properties of the ammonium nitrate and higher shock sensitivity. The experimental data also show that the ammonium nitrate samples obtained by preconcentrating the original solutions with the ammonium formate to 80-83% NH/sub 4/NO/sub 3/, followed by fluid-bed granulation, have the highest shock sensitivity.

Kil'man, Y.I.; Usachev, V.A.; Vakhrushev, Y.A.

1985-06-20

384

Equilibrium Studies of Sodium-Ammonium, Potassium-Ammonium, and Calcium-Ammonium Exchanges on Clinoptilolite Zeolite  

Microsoft Academic Search

Forward and reverse ion-exchange isotherms for the binary sodium-ammonium, potassium-ammonium, and calcium-ammonium systems on clinoptilolite have been measured in aqueous solutions at a total concentration of 0.1 equiv\\/dm and at 298 K. Prior to exchange experiments it was attempted to prepare homoionic forms of the zeolite by exhaustive treatments with appropriate salt solutions of cations. With no binary exchanges, full

M. A. Jama; H. Yuecel

1989-01-01

385

Field leaching of alkaline copper quaternary-treated red pine lumber over 3 years: long-term dynamics.  

PubMed

Alkaline copper quaternary (ACQ), a wood preservative, consists of copper oxide and quaternary ammonium compounds. Three red pine piles were monitored over 3 years to evaluate the dynamics of contaminant leaching from ACQ-treated and untreated lumber. There were small temporal changes in the volumetric leachate/rain ratio with the ACQ-treated lumber, while the volumetric ratio decreased across the 3 years with the untreated lumber, most likely due to considerable weathering that increased the capacity of the untreated lumber to absorb rain water. The average copper (Cu) concentration in leachate from the ACQ-treated lumber (4,033 ?g/L) was much higher than that in leachate from the untreated lumber (87 ?g/L) and rain (48 ?g/L) in the first leaching year. Cu concentration in leachate from the ACQ-treated lumber in the second and third years decreased to 46-51% of that in the first year. There were significant seasonal decreases of Cu concentration in leachate from the ACQ-treated lumber, which were correlated to exposure time and meteorological parameters. ACQ-treatment did not affect leachate pH and concentrations of quaternary ammonium compounds and chemical oxygen demand. There were insignificant temporal changes of leachate pH and concentrations of chemical oxygen demand and total dissolved solids in leachate from both ACQ-treated and untreated lumber piles. PMID:24718339

Tao, Wendong

2014-01-01

386

Ammonium azide under hydrostatic compression  

NASA Astrophysics Data System (ADS)

The properties of ammonium azide NH4N3 upon compression were investigated using first-principles density functional theory. The equation of state was calculated and the mechanism of a phase transition experimentally observed at 3.3 GPa is elucidated. Novel polymorphs of NH4N3 were found using a simple structure search algorithm employing random atomic displacements upon static compression. The structures of three new polymorphs, labelled as B, C, and D, are similar to those of other metal azides.

Landerville, A. C.; Steele, B. A.; Oleynik, I. I.

2014-05-01

387

Ammonium Metabolism in the Green Hydra Symbiosis  

Microsoft Academic Search

Abstract. Inhibitors of enzymes,of ammonium,assimi- lation were used to test if assimilation of ammonium,in the green,hydra-Chlorella symbiosis,was,due,to host or symbionts. Both methionine sulphoximine (MSX, an in- hibitor of glutamine synthetase, found in both host and symbionts) and azaserine (AZS, an inhibitor of 2-oxoglu- tarate amido transferase, not found in the host) inhibited ammonium,uptake by the intact symbiosis. MSX was taken

P. J. Mcauley

1995-01-01

388

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

389

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

390

Quaternary glaciation of Mount Everest  

NASA Astrophysics Data System (ADS)

The Quaternary glacial history of the Rongbuk valley on the northern slopes of Mount Everest is examined using field mapping, geomorphic and sedimentological methods, and optically stimulated luminescence (OSL) and 10Be terrestrial cosmogenic nuclide (TCN) dating. Six major sets of moraines are present representing significant glacier advances or still-stands. These date to >330 ka (Tingri moraine), >41 ka (Dzakar moraine), 24-27 ka (Jilong moraine), 14-17 ka (Rongbuk moraine), 8-2 ka (Samdupo moraines) and ˜1.6 ka (Xarlungnama moraine), and each is assigned to a distinct glacial stage named after the moraine. The Samdupo glacial stage is subdivided into Samdupo I (6.8-7.7 ka) and Samdupo II (˜2.4 ka). Comparison with OSL and TCN defined ages on moraines on the southern slopes of Mount Everest in the Khumbu Himal show that glaciations across the Everest massif were broadly synchronous. However, unlike the Khumbu Himal, no early Holocene glacier advance is recognized in the Rongbuk valley. This suggests that the Khumbu Himal may have received increased monsoon precipitation in the early Holocene to help increase positive glacier mass balances, while the Rongbuk valley was too sheltered to receive monsoon moisture during this time and glaciers could not advance. Comparison of equilibrium-line altitude depressions for glacial stages across Mount Everest reveals asymmetric patterns of glacier retreat that likely reflects greater glacier sensitivity to climate change on the northern slopes, possibly due to precipitation starvation.

Owen, Lewis A.; Robinson, Ruth; Benn, Douglas I.; Finkel, Robert C.; Davis, Nicole K.; Yi, Chaolu; Putkonen, Jaakko; Li, Dewen; Murray, Andrew S.

2009-07-01

391

Structural study of ammonium metatungstate  

SciTech Connect

Several techniques have been used to study the structure of the Keggin-type polyoxometalate salt ammonium metatungstate (AMT)-(NH{sub 4}){sub 6}[H{sub 2}W{sub 12}O{sub 40}]*nH{sub 2}O, 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{approx_equal}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. - Graphical abstract: The structure of ammonium metatungstate powders are highly dependent on hydration and POM molecule rotation, with cation and hydrogen bonding forces directing a mixture of structures that have been studied with bulk and single-crystal methods. The illustration shows Monte Carlo simulated anion structural disorder for the fully dehydrated form of the title compound.

Christian, Joel B. [OSRAM SYLVANIA Global Tungsten and Powders, Towanda, PA 18848 (United States); SUNY at Binghamton, Materials Science Program, Binghamton, NY 13902 (United States)], E-mail: joel.christian@sylvania.com; Whittingham, M. Stanley [SUNY at Binghamton, Materials Science Program, Binghamton, NY 13902 (United States)

2008-08-15

392

Cs 2Gd 6N 2Te 7: The first quaternary nitride telluride of the lanthanides  

Microsoft Academic Search

The first quaternary nitride telluride with trivalent gadolinium, Cs2Gd6N2Te7, was obtained by the reaction of metallic gadolinium with cesium azide, elemental tellurium, and gadolinium trichloride as well as cesium chloride as flux at 900°C for 7 days in evacuated silica tubes. Single crystals occur as long black needles and crystallize in the monoclinic space group C2\\/m (a=2403.1(2)pm, b=424.03(3)pm, c=1142.91(7)pm, ?=103.709(4)°,

Falk Lissner; Thomas Schleid

2006-01-01

393

Ice Age refugia and Quaternary extinctions: An issue of Quaternary evolutionary palaeoecology  

NASA Astrophysics Data System (ADS)

Quaternary palaeoecology, as a discipline, involves the analysis of a large range of fossil organisms from the last ca. 2 million years. This paper considers the role that these Quaternary records can take in better understanding the evolution of those organisms. We also discuss the surprisingly low uptake of evolutionary biology in Quaternary palaeoecological studies. This leads us to encourage an advance on both these fronts with a greater degree of collaboration with phylogeographic and ancient DNA researchers. These discussions accompany a summary of a special issue of Quaternary Science Reviews representing the proceedings of the XVII INQUA held in Cairns Australia in 2007. This special issue includes papers on a wide variety of Quaternary evolutionary palaeoecological and population dynamic subjects including extinct Pacific Island palm trees, Beringian beetles, Scandinavian trees, and the effects on human and animal populations of an extraterrestrial impact event in the Late Glacial of North America.

Stewart, John R.; Cooper, Alan

2008-12-01

394

Phosphonium chloride for thermal storage  

NASA Technical Reports Server (NTRS)

Development of systems for storage of thermal energy is discussed. Application of phosphonium chloride for heat storage through reversible dissociation is described. Chemical, physical, and thermodynamic properties of phosphonium chloride are analyzed and dangers in using phosphonium chloride are explained.

Sutton, J. G.; Heimlich, P. F.; Tepper, E. H.

1972-01-01

395

Carcinogenicity of vinyl chloride and vinylidene chloride  

Microsoft Academic Search

Exposure of mice to 50, 250, or 1000 ppm of vinyl chloride (VC) in the air for 6 h\\/d, 5 d\\/wk, caused a high incidence of bronchioloalveolar adenoma, mammary gland tumors, and hemangiosarcoma. Mammary gland tumors occurred in the females and included ductular odenocarcinoma and squamous and anaplastic cell carcinomas with metastasis to the lung. Hemangiosarcoma occurred in the liver

C. C. Lee; J. C. Bhandari; J. M. Winston; W. B. House; R. L. Dixon; J. S. Woods

1978-01-01

396

An Electronic Tongue Designed to Detect Ammonium Nitrate in Aqueous Solutions  

PubMed Central

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.

Campos, Inmaculada; Pascual, Lluis; Soto, Juan; Gil-Sanchez, Luis; Martinez-Manez, Ramon

2013-01-01

397

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.; NH?NO?; MgSO?; NH?Cl; NaCl; Na?CO?; (NH?)?SO?; MgCl?; Na?PO?; K?SO?; K?CO?; CaCl?; NaH?PO?; KCl; NaNO?; K?HPO?. 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

2013-01-01

398

EXCHANGE PROPERTIES OF AMMONIUM SALTS OF 12-HETEROPOLYACIDS. IV. Cs EXCHANGE ON AMMONIUM PHOSPHOTUNGSTATE AND PHOSPHOMOLYBDATE  

Microsoft Academic Search

Functional relations have been established describing cesium sorption on ; ammonium phosphotungstate (NHâPW) and ammonium phosphomolybdate (NHâ; PMo) as a function of the concentrations of nitric acid, ammonium nitrate, and ; cesium in the solution, and on the amount of sorbent. (auth);

J Krtil

1962-01-01

399

Biological Treatment of Ammonium-Rich Wastewater with the Partial Nitrification and Anaerobic Ammonium Oxidation  

Microsoft Academic Search

The aim of the investigation was to evaluate the nitrogen removal efficiency by using the combined partial nitrification and anaerobic ammonium oxidation (anammox) process for high-strength ammonium synthetic wastewater. The partial nitrification and anaerobic ammonium oxidation reactors were inoculate with domesticated sludge and operated respectively during the startup period. Subsequently, they were combined for stable operation when the partial nitrification

Qinglin Xie; Xiaoxia Li; Shaoyuan Bai; Yanhong Li

2010-01-01

400

Surface treatment for preventing decay and termite attack in wood using didecyl dimethyl ammonium tetrafluoroborate (DBF) incorporated with acryl-silicon type resin  

Microsoft Academic Search

Surface treatment of wood was carried out using acryl-silicon type resin including didecyl dimethyl ammonium tetrafluoroborate (DBF), boron-containing quaternary ammonia compound. Surface-treated wood specimens were exposed laboratory decay resistance tests after completing a 10-cyle severe weathering process. In laboratory decay resistance tests, one brown-rot decay fungus, Fomitopsis palustris and one white-rot decay fungus, Trametes versicolor were used. The specimens were

W. J. Hwang; S. N. Kartal; K. Shinoda; Y. Imamura

2005-01-01

401

Experimental and Theoretical Investigation into the Correlation Between Mass and Ion Mobility for Choline and Other Ammonium Cations in N 2  

Microsoft Academic Search

\\u000a A number of tertiary amine and quaternary ammonium cations spanning a mass range of 60–146 amu (trimethylamine, tetramethylammonium,\\u000a trimethylethylammonium, N, N-dimethylaminoethanol, choline, N, N-dimethylglycine, betaine, acetylcholine, (3-carboxypropyl)trimethylammonium) were investigated using electrospray ionization\\u000a ion mobility spectrometry. Measured ion mobilities demonstrate a high correlation between mass and mobility in N2. In addition, identical mobilities within experimental uncertainties are observed for structurally dissimilar

Hyungjun Kim

402

Equilibrium studies of sodium-ammonium potassium-ammonium, and calcium-ammonium exchanges on clinoptilolite zeolite  

SciTech Connect

Forward and reverse ion-exchange isotherms for the binary sodium-ammonium, potassium-ammonium, and calcium-ammonium systems on clinoptilolite have been measured in aqueous solutions at a total concentration of 0.1 equiv/dm{sup 3} and at 298 K. Prior to exchange experiments it was attempted to prepare homoionic forms of the zeolite by exhaustive treatments with appropriate salt solutions of cations. With no binary exchanges, full replacement of the cation by the ammonium ion is observed, which conflicts with some earlier work on clinoptilolite. Despite the observed partial exchange levels, clinoptilolite shows a very high preference for ammonium ion over sodium and calcium but not over potassium. Thermodynamic values for the exchanges were calculated and compared with data in the literature. Both the selectivity and thermodynamic affinity sequence, in agreement with previous work reported in the literature, are K{sup +} > NH{sub 4}{sup +} > Na{sup +} > Ca{sup 2+}.

Jama, M.A.; Yuecel, H. (Middle East Technical Univ., Ankara (Turkey))

1989-12-01

403

Strontium-Isotope Studies Of Chloride-Contaminated Groundwater, Denmark  

NASA Astrophysics Data System (ADS)

Saline groundwater has three principal origins in Denmark: 1) Seawater infiltration into nearcoastal aquifers, 2) saline formation water in aquifers of marine sedimentary origin, and 3) intrusion of brines from deep saline formation waters and evaporitic deposits in the subsurface. Strontium-isotope studies of chloride-contaminated groundwater from a Quaternary sandy aquifer at Stautrup Waterworks, Denmark, indicate that the groundwater is heavily influenced by saline formation water from underlying Oligocene marine mica clay. Thus, strontium isotopic hydrochemical criteria were successfully used to identify the sources of saline groundwater.

Jørgensen, N. O.; Holm, P. M.

1995-02-01

404

Comparative toxicity of ammonium and nitrate compounds to Pacific treefrog and African clawed frog tadpoles  

SciTech Connect

The effects of ammonium nitrate, ammonium chloride, ammonium sulfate, and sodium nitrate on survival and growth of Pacific treefrog (Pseudacris regilla [Baird and Girard]) and African clawed frog (Xenopus laevis [Daudin]) tadpoles were determined in static-renewal tests. The 10-d ammonium nitrate and ammonium sulfate LC50s for P. regilla were 55.2 and 89.7 mg/L NH{sub 4}-N, respectively. The 10-d LC50s for X. laevis for the three ammonium compounds ranged from 45 to 64 mg/L NH{sub 4}-N. The 10-d sodium nitrate LC50s were 266.2 mg/L NO{sub 3}-N for P. regilla and 1,236.2 mg/L NO{sub 3}-N for X. laevis. The lowest observed adverse effect level (LOAEL) of ammonium compound based on reduced length or weight was 24.6 mg/L NH{sub 4}-N for P. regilla and 99.5 mg/L NH{sub 4}-N for X. laevis. The lowest sodium nitrate LOAELs based on reduced length or weight were {lt}30.1 mg/L NO{sub 3}-N for P. regilla and 126.3 mg/L NO{sub 3}-N for X. laevis. Calculated un-ionized NH{sub 3} comprised 0.3 to 1.0% of measured NH{sub 4}-N concentrations. Potential harm to amphibians could occur if sensitive life stages were impacted by NH{sub 4}-N and NO{sub 3}-N in agricultural runoff or drainage for a sufficiently long period.

Schuytema, G.S.; Nebeker, A.V.

1999-10-01

405

Phase diagram of ammonium nitrate.  

PubMed

Ammonium Nitrate (AN) is a fertilizer, yet becomes an explosive upon a small addition of chemical impurities. The origin of enhanced chemical sensitivity in impure AN (or AN mixtures) is not well understood, posing significant safety issues in using AN even today. To remedy the situation, we have carried out an extensive study to investigate the phase stability of AN and its mixtures with hexane (ANFO-AN mixed with fuel oil) and Aluminum (Ammonal) at high pressures and temperatures, using diamond anvil cells (DAC) and micro-Raman spectroscopy. The results indicate that pure AN decomposes to N2, N2O, and H2O at the onset of the melt, whereas the mixtures, ANFO and Ammonal, decompose at substantially lower temperatures. The present results also confirm the recently proposed phase IV-IV' transition above 17 GPa and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400°C. PMID:24320387

Dunuwille, Mihindra; Yoo, Choong-Shik

2013-12-01

406

Winter Wheat Fertilization: Post Ammonium Nitrate  

Microsoft Academic Search

Summary The potential for overwinter losses of nitrogen by denitrification and leaching have led to the recommendation that nitrogen fertilization of winter wheat be done using ammonium nitrate broadcast in the spring. However, spring broadcast application of urea can result in significant loss of nitrogen by volatilization and immobilization by surface residues. Since prilled ammonium nitrate is not available for

R. Byron Irvine; Guy Lafond; Randy Kutcher

407

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

408

Conversion of sodium chloride to hydrogen chloride in the atmosphere  

Microsoft Academic Search

A reaction route is suggested, based on experimental results, for the conversion of sodium chloride particles to gaseous hydrogen chloride in the atmosphere. The first step is the hydrolysis of nitrogen dioxide (NOâ) to form nitric acid (HNOâ) vapor. The second step is either adsorption on the relatively dry sodium chloride and the fourth is desorption of the hydrogen chloride,

R. C. Robbins; R. D. Cadle; D. L. Eckhardt

1959-01-01

409

21 CFR 582.1127 - Aluminum ammonium sulfate.  

Code of Federal Regulations, 2013 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

410

21 CFR 182.1127 - Aluminum ammonium sulfate.  

Code of Federal Regulations, 2013 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

411

40 CFR 721.10302 - Zinc ammonium phosphate (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Zinc ammonium phosphate (generic). 721.10302 Section...Substances § 721.10302 Zinc ammonium phosphate (generic). (a) Chemical substance...identified generically as zinc ammonium phosphate (PMN P-00-442) is subject...

2013-07-01

412

21 CFR 184.1141a - Ammonium phosphate, monobasic.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Ammonium phosphate, monobasic. 184.1141a Section 184...Affirmed as GRAS § 184.1141a Ammonium phosphate, monobasic. (a) Ammonium phosphate, monobasic (NH4 H2 PO4 , CAS...

2013-04-01

413

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

414

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

415

Ammonium Uptake by Micronesian Species of Gracilaria (Rhodophyta).  

National Technical Information Service (NTIS)

Research was carried out to examine the kinetics of ammonium uptake by thalli of several Gracilaria species from Micronesia to evaluate their relative potential for removing ammonium from mariculture systems. It was found that ammonium uptake was dependen...

S. G. Nelson R. N. Tsutsui

1981-01-01

416

[Congenital chloride diarrhea].  

PubMed

Congenital chloride diarrhea (CCD) is a rare hereditary disease, with a prenatal onset, secondary to a deficit in the intestinal chloride transport. In the present study, we describe the clinical characteristics of three patients with congenital watery diarrhea, two of them females, aged between 9 and 14 months at the first visit. All patients presented perinatal antecedents of polyhydramnios and prematurity, watery stools since birth and growth failure. Metabolic alkalosis, hypokalemia and hypochloremia were found. Stool ionogram with elevated doses of chloride, exceeding both sodium and potassium, confirmed the diagnosis of CCD. Substitute treatment with sodium and potassium chloride was started with good results. CCD should be considered as a differential diagnosis to congenital watery diarrhea, since early diagnosis and appropriate treatment are mandatory for the normal development of the child, avoiding severe complications such as neurological sequelae and even death. PMID:16127986

Contreras, Mónica; Rocca, Ana; Benedetti, Laura; Kakisu, Hisae; Delgado, Sabrina; Ruiz, José Antonio

2005-01-01

417

Hydrogen chloride test set  

NASA Technical Reports Server (NTRS)

Detector uses tertiary amine, which makes reaction fairly specific for relatively small highly polarized hydrogen chloride molecule. Reaction is monitored by any microbalance capable of measuring extremely small mass differences in real time.

Workman, G. L.

1976-01-01

418

40 CFR 61.65 - Emission standard for ethylene dichloride, vinyl chloride and polyvinyl chloride plants.  

Code of Federal Regulations, 2010 CFR

...dichloride, vinyl chloride and polyvinyl chloride plants. 61.65 Section...dichloride, vinyl chloride and polyvinyl chloride plants. An owner or operator...vinyl chloride, and/or polyvinyl chloride plant shall comply with...

2010-07-01

419

The radiolysis of poly(4-vinylpyridine) quaternary salt ion exchange resins  

NASA Astrophysics Data System (ADS)

The radiation chemical yields of gaseous products, especially molecular hydrogen (H 2), have been determined in the radiolysis of different poly(4-vinylpyridine) quaternary salt ion exchange resins with up to about 30 wt% of absorbed water. Irradiations were performed with 5 MeV 4He ions to simulate ?-particle radiolysis and with ?-rays for comparison. The resins were quaternary salts of chloride and nitrate that are commonly used as matrixes in anion exchange and in plutonium recovery processes. An increase in H 2 yields with increasing water loading was observed for both types of ionizing radiation in all of the resins. The yield of H 2 for the nitrate-form was lower than that for the chloride and the yield of H 2 was lower when the pyridinium nitrogen atom is coordinated to a methyl group rather than to atomic hydrogen. Spectroscopic studies included UV/vis, IR, and Raman and suggested that all the resins exhibit a high radiolytic stability.

Enomoto, Kazuyuki; LaVerne, Jay A.; Tandon, Lav; Enriquez, Alejandro E.; Matonic, John H.

2008-02-01

420

THE SALTING OUT OF GELATIN INTO TWO LIQUID LAYERS WITH SODIUM CHLORIDE AND OTHER SALTS  

PubMed Central

1. Conditions under which gelatin may be salted out into two liquid layers at 35° were studied. 2. The equilibria governing the amounts and composition of the layers salted out with sodium chloride are found to accord with the requirements of the phase rule for the quaternary system gelatin-sodium chloride-hydrogen ion-water. 3. So far, soaps and gelatin are found to be surprisingly similar in their behaviour and definite indications are given as to where further similarities may be sought. 4. It is evident from this work that the term "coagulation" as ordinarily applied to the salting out of proteins is definitely a misnomer.

McBain, James W.; Kellogg, Frederick

1928-01-01

421

Investigation of the Soret effect in binary, ternary and quaternary hydrocarbon mixtures: New expressions for thermodiffusion factors in quaternary mixtures  

Microsoft Academic Search

Thermodiffusion or the Soret effect in binary, ternary and quaternary hydrocarbon mixtures is studied. Using the linear non-equilibrium thermodynamic (LNET) approach, expressions are derived for the estimation of the thermodiffusion coefficients or factors in quaternary mixtures using different approaches. New series of experimental data for binary, ternary and quaternary mixtures are used to evaluate the performance of the Firoozabadi, Kempers

Morteza Eslamian; M. Ziad Saghir; M. Mounir Bou-Ali

2010-01-01

422

Mechanism by which ammonium bicarbonate and ammonium sulfate inhibit mycotoxigenic fungi.  

PubMed Central

In this study we examined the mechanism by which ammonium bicarbonate inhibits mycotoxigenic fungi. Elevated extracellular pH, alone, was not responsible for the antifungal activity. Although conidia of Penicillium griseofulvum and Fusarium graminearum had internal pH (pHi) values as high as 8.0 in buffer at an external pH (pHo) of 9.5, their viability was not markedly affected. The pHi values from conidia equilibrated in glycine-NaOH-buffered treatments without ammonium bicarbonate or ammonium sulfate were similar to values obtained from buffered treatments containing the ammonium salts. Thus, inhibition did not appear to be directly related to increased pHi. Ammonium sulfate in buffered media at pH greater than or equal to 8.7 was as inhibitory as ammonium bicarbonate, but was completely ineffective at pH less than or equal to 7.8. The hypothesis that free ammonia caused the fungal inhibition was tested by using ammonium sulfate as a model for ammonium bicarbonate. Viability, expressed as log CFU/ml, and percent germination of P. griseofulvum and F. graminearum decreased dramatically as the free ammonia concentration increased. Germination rate ratios (the germination rate in buffered ammonium sulfate divided by the germination rate in buffer alone) decreased linearly as the free ammonia concentration increased, further establishing NH3 as the toxic agent. Ammonium bicarbonate inhibits fungi because the bicarbonate anion supplies the alkalinity necessary to establish an antifungal concentration of free ammonia.

DePasquale, D A; Montville, T J

1990-01-01

423

Ionic liquid electrolytes based on multi-methoxyethyl substituted ammoniums and perfluorinated sulfonimides: Preparation, characterization, and properties  

Microsoft Academic Search

New functionalized ionic liquids (ILs), comprised of multi-methoxyethyl substituted quaternary ammonium cations (i.e. [N(CH2CH2OCH3)4?n(R)n]+; n=1, R=CH3OCH2CH2; n=1, R=CH3, CH2CH3; n=2, R=CH3CH2), and two representative perfluorinated sulfonimide anions (i.e. bis(fluorosulfonyl)imide (FSI?) and bis(trifluoromethanesulfonyl)imide (TFSI?)), were prepared. Their fundamental properties, including phase transition, thermal stability, viscosity, density, specific conductivity and electrochemical window, were extensively characterized. These multi-ether functionalized ionic liquids exhibit good

Hong-Bo Han; Kai Liu; Shao-Wei Feng; Si-Si Zhou; Wen-Fang Feng; Jin Nie; Hong Li; Xue-Jie Huang; Hajime Matsumoto; Michel Armand; Zhi-Bin Zhou

2010-01-01

424