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Query: UMLS:C0016382 (flushing)
 6,387 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Zein, the prolamine of corn, has been investigated for its potential as an industrial biopolymer. In previous research, zein was plasticized with oleic acid and formed into sheets/films. Physical properties of films were affected by film structure and controlled in turn by zein-oleic acid interactions. The nature of such interactions is not well understood. Thus, protein-fatty acid interactions were investigated in this work by the use of surface plasmon resonance (SPR). Zein adsorption from 75% aqueous 2-propanol solutions, 0.05% to 0.5% w/v, onto hydrophilic and hydrophobic self-assembled monolayers (SAMs) formed by 11-mercaptoundecanoic acid and 1-octanethiol, respectively, was monitored by high time resolution SPR. Initial adsorption rate and ultimate surface coverage increased with bulk protein concentration for both surfaces. The initial slope of plotted adsorption isotherms was higher on 11-mercaptoundecanoic acid than on 1-octanethiol, indicating higher zein affinity for hydrophilic SAMs. Also, maximum adsorption values were higher for zein on hydrophilic than on hydrophobic SAMs. Flushing off loosely bound zein in the SPR cell allowed estimation of apparent monolayer values. Differences in monolayer values for hydrophobic and hydrophilic surfaces were explained in terms of zein adsorption footprint.
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PMID:Zein adsorption to hydrophilic and hydrophobic surfaces investigated by surface plasmon resonance. 1524 51

The adsorption of a commercial zein sample on carboxylic (COOH) and alkyl (CH(3)) surfaces was monitored by high time resolution surface plasmon resonance. Zein showed higher affinity and higher mass adsorption on carboxylic than alkyl surfaces. A zein layer specific for each surface was obtained after flushing off loosely bound zein with 75% 2-propanol solutions. Zein deposits were examined under atomic force microscopy. Differences in layer thickness between carboxylic and alkyl surfaces were explained in terms of zein adsorption footprint.
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PMID:Zein dynamic adsorption to carboxylic and alkyl coated surfaces. 1641 14

The ability of two biodegradable surfactants, polyoxyethylene (20) sorbitan monooleate (Tween 80) and sodium dihexyl sulfosuccinate (Aerosol MA), to recover a representative dense non-aqueous-phase liquid (DNAPL), trichloroethene (TCE), from heterogeneous porous media was evaluated through a combination of batch and aquifer cell experiments. An aqueous solution containing 3.3% Aerosol MA, 8% 2-propanol and 6 g/l CaCl(2) yielded a weight solubilization ratio (WSR) of 1.21 g TCE/g surfactant, with a corresponding liquid-liquid interfacial tension (IFT) of 0.19 dyn/cm. Flushing of aquifer cells containing a TCE-DNAPL source zone with approximately two pore volumes of the AMA formulation resulted in substantial (>30%) mobilization of TCE-DNAPL. However, a TCE mass recovery of 81% was achieved when the aqueous-phase flow rate was sufficient to displace the mobile TCE-DNAPL toward the effluent well. Aqueous solutions of Tween 80 exhibited a greater capacity to solubilize TCE (WSR=1.74 g TCE/g surfactant) and exerted markedly less reduction in IFT (10.4 dyn/cm). These data contradict an accepted empirical correlation used to estimate IFT values from solubilization capacity, and indicate a unique capacity of T80 to form concentrated TCE emulsions. Flushing of aquifer cells with less than 2.5 pore volumes of a 4% T80 solution achieved TCE mass recoveries ranging from 66 to 85%, with only slight TCE-DNAPL mobilization (<5%) occurring when the total trapping number exceeded 2 x 10(-5). These findings demonstrate the ability of Tween 80 and Aerosol MA solutions to efficiently recover TCE from a heterogeneous DNAPL source zone, and the utility of the total trapping number as a design parameter for a priori prediction of DNAPL mobilization and bank angle formation when flushing with low-IFT solutions. Given their potential to stimulate microbial reductive dechlorination at low concentrations, these surfactants are well-suited for remedial action plans that couple aggressive mass removal followed by enhanced bioremediation to treat chlorinated solvent source zones.
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PMID:Evaluation of trichloroethene recovery processes in heterogeneous aquifer cells flushed with biodegradable surfactants. 1762 5

By employing multi-dimension gas chromatography with capillary flow technology in combination with highly selective capillary columns and a pressurized liquid injection system, light oxygenated compounds such as methanol, ethanol, n-propanol, 2-propanol, and n-butanol in the presence of either light hydrocarbon, heavy hydrocarbon, or aromatic matrices can be measured accurately with minimal possibility of a false positive. Using this technique, a detection limit of at least 0.20 ppm (w/w) with a linear correlation coefficient greater than 0.9993 over a range from 0.5 ppm to 600 ppm (w/w) and a relative standard deviation of greater than 2.7% are achieved for the solutes tested. The technique can also be effective for the measurement of other classes of oxygenated compounds such as ethers, aldehydes, and ketones. Another added benefit for the implementation of capillary flow technology is the capability to conduct column back-flushing, where heavier, undesired solutes in a sample can be back-flushed from the chromatographic system to improve system cleanliness and sample throughput.
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PMID:Capillary flow technology with multi-dimensional gas chromatography for trace analysis of oxygenated compounds in complex hydrocarbon matrices. 1807 74

Functionalized monolithic columns were prepared via ring-opening metathesis polymerization (ROMP) within silanized fused silica capillaries with an internal diameter of 200 microm by in situ grafting. This procedure is conducted in two steps, the first of which is the formation of the basic monolithic structure by polymerization of norborn-2-ene (NBE) and 1,4,4a,5,8,8a-hexahydro-1,4,5,8-exo,endo-dimethanonaphthalene (DMN-H6) in a porogenic system (toluene and 2-propanol) using RuCl(2)(PCy(3))(2)(CHPh) as ROMP initiator. In the second step the still active initiator sites located on the surface of the structure-forming microglobules were used as receptor groups for the attachment ("grafting") of functional groups onto the monolithic backbone by flushing the monolith with 7-oxanorborn-2-ene-5,6-carboxylic anhydride (ONDCA). Functionalization conditions were first defined that did not damage the backbone of low polymer content (20%) monoliths allowing high-throughput chromatographic separations. Variation of the functionalization conditions was then shown to provide a means of controlling the degree of functionalization and resulting ion-exchange capacity. The maximum level of in situ ONDCA grafting was obtained by a 3h polymerization in toluene at 40 degrees C. The weak cation-exchange monoliths obtained provided good separation of a standard peptide mixture comprising four synthetic peptides designed specifically for the evaluation of cation-exchange columns. An equivalent separation was also achieved using the lowest capacity column studied, indicative of a high degree of robustness of the functionalization procedure. As well as demonstrably bearing ionic functional groups enabling analyte separation in the cation-exchange mode, the columns exhibited additional hydrophobic characteristics which influenced the separation process. The functionalized monoliths thus represent useful tools for mixed-mode separations.
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PMID:Ring-opening metathesis polymerization for the preparation of norbornene-based weak cation-exchange monolithic capillary columns. 1902 22

A dicationic ruthenium-alkylidene complex [Ru(dmf)(3)(IMesH(2))(=CH-2-(2-PrO)-C(6)H(4))][(BF(4))(2)] (1; IMesH(2) =1,3-dimesitylimidazolin-2-ylidene) has been prepared and used in continuous metathesis reactions by exploiting supported ionic-liquid phase (SILP) technology. For these purposes, ring-opening metathesis polymerization (ROMP)-derived monoliths were prepared from norborn-2-ene, tris(norborn-5-ene-2-ylmethyloxy)methylsilane, and [RuCl(2)(PCy(3))(2)(CHPh)] (Cy=cyclohexyl) in the presence of 2-propanol and toluene and surface grafted with norborn-5-en-2-ylmethyl-N,N,N-trimethylammonium tetrafluoroborate ([NBE-CH(2)-NMe(3)][BF(4)]). Subsequent immobilization of the ionic liquid (IL), 1-butyl-2,3-dimethylimidazolium tetrafluoroborate ([BDMIM][BF(4)]), containing ionic catalyst 1 created the SILP catalyst. The use of a second liquid transport phase, which contained the substrate and was immiscible with the IL, allowed continuous metathesis reactions to be realized. High turnover numbers (TONs) of up to 3700 obtained in organic solvents for the ring-closing metathesis (RCM) of, for example, N,N-diallyltrifluoroacetamide, diethyl diallylmalonate, diethyl di(methallyl)malonate, tert-butyl-N,N-diallylcarbamate, N,N-diallylacetamide, diphenyldiallylsilane, and 1,7-octadiene, as well as in the self-metathesis of methyl oleate, could be further increased by using biphasic conditions with [BDMIM][BF(4)]/heptane. Under continuous SILP conditions, TONs up to 900 were observed. Due to the ionic character of the initiator, catalyst leaching into the transport phase was very low (<0.1 %). Finally, the IL can, together with decomposed catalyst, be removed from the monolithic support by flushing with methanol. Upon reloading with [BDMIM][BF(4)]/1, the recycled support material again qualified for utilization in continuous metathesis reactions.
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PMID:A dicationic ruthenium alkylidene complex for continuous biphasic metathesis using monolith-supported ionic liquids. 2299 38