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Microbes in aquifers are present suspended in groundwater or attached to the aquifer sediment. Groundwater is often sampled at gasoline ether oxygenate (GEO)-impacted sites to assess the potential biodegradation of organic constituents. However, the distribution of GEO-degrading microorganisms between the groundwater and aquifer sediment must be understood to interpret this potential. In this study, the distribution of ethyl tert-butyl ether (ETBE)-degrading organisms and ETBE biodegradation potential was investigated in laboratory microcosm studies and mixed groundwater-aquifer sediment samples obtained from pumped monitoring wells at ETBE-impacted sites. ETBE biodegradation potential (as determined by quantification of the ethB gene) was detected predominantly in the attached microbial communities and was below detection limit in the groundwater communities. The copy number of ethB genes varied with borehole purge volume at the field sites. Members of the Comamonadaceae and Gammaproteobacteria families were identified as responders for ETBE biodegradation. However, the detection of the ethB gene is a more appropriate function-based indicator of ETBE biodegradation potential than taxonomic analysis of the microbial community. The study shows that a mixed groundwater-aquifer sediment (slurry) sample collected from monitoring wells after minimal purging can be used to assess the aquifer ETBE biodegradation potential at ETBE-release sites using this function-based concept.

The aim of this work was to investigate the technical as well as the economic feasibility of producing 2-ethyl hexyl oleate (2-EHO), a non-phthalate plasticizer in a solvent free medium. The esterification reaction between oleic acid and 2-ethyl hexyl alcohol was carried out in a packed bed reactor (PBR) using Candida antarctica lipase B (Novozym 435; Novozymes; Copenhagen-Denmark) as biocatalyst. RSM was employed to optimize the esterification reaction conditions. The optimum reaction conditions were found to be flow rate of 1.5 mL/min, No. of cycles of 12 and molar ratio of 4:1 2-ethyl hexanol to oleic acid. The maximum experimental and predicated conversions were found to be 95.8% and 95.61% respectively. Formation of 2-EHO was approved by FTIR, 1HNMR and 13CNMR. From the economic prospective, PBR was capable of producing 2-EHO with a purity of more than 94% over 480 h without remarkable reduction of enzyme activity. This revealed an economic production of 2-EHO at a yield of 2 tons kg-1 lipase. The manufacturing cost was found to be $ 1.88 /kg 2-EHO, this contributed to a profit of about 30% compared to the commercial price of 2-EHO. Such results approve the technical and economic feasibility for this sustainable method in esters production.

Aqueous-liquid crystal (LC) interfaces offer promise as responsive interfaces at which biomolecular recognition events can be amplified into macroscopic signals. However, the design of LC interfaces that distinguish between specific and non-specific protein interactions remains an unresolved challenge. Herein we report the synthesis of amphiphilic monomers, dimers and trimers conjugated to sulfonamide ligands via triazole rings, their assembly at aqueous-LC interfaces, and the orientational response of LCs to the interactions of carbonic anhydrase II (CAII) and serum albumin with the oligomer-decorated LC interfaces. Of six oligomers synthesized, only dimers without amide methylation were found to assemble at aqueous interfaces of nematic 4-cyano-4’-pentylbiphenyl (5CB) to induce perpendicular LC orientations. At dimer-decorated LC interfaces, we found that concentrations of CAII less than 4 μM did not measurably perturb the LC but prevented non-specific adsorption and penetration of serum albumin into the dimer-decorated interface that otherwise triggered bright, globular LC optical domains. These experiments and others (including competitive adsorption of CAII, BSA and lysozyme) support our hypothesis that specific binding of CAII to the dimer prevents LC anchoring transitions triggered by non-specific adsorption of serum albumin. We illustrate the utility of the approach by reporting (i) the relative activity of two small molecule inhibitors (6-ethoxy-2-benzothiazolesulfonamide and benzenesulfonamide) of binding of CAII to sulfonamide, and (ii) proteolytic digestion of a protein (CAII) by thermolysin. Overall, the results in this paper provide new insight into the interactions of proteins at aqueous-LC interfaces and fresh ideas for either blocking non-specific interactions of proteins at surfaces or reporting specific binding events at LC interfaces in the presence of non-specific proteins.

In this work, a systematic investigation on the mechanism and kinetics of the reactions of t-amyl methyl ether (TAME) and t-amyl ethyl ether (TAEE) with OH radicals in the gas phase has been performed within the Density Functional Theory (DFT) framework. The potential energy surfaces were obtained at the M06-2X/6-311++G(d,p) level. Kinetic data for the initial step in the oxidative degradation of TAME and TAEE were obtained, as well as branching ratios between the possible reaction channels. The calculated total rate constants are 3.9 × 10−11 cm3 molecules−1 s−1 and 1.3 × 10−12 cm3 molecules−1 s−1, for TAME and TAEE, respectively. Contrary to what occurs in the case of the MTBE and ETBE oxidation initiated by OH radicals, for TAME and TAEE the H-abstraction from α methoxy or ethoxy groups is not favored. For both molecules, the contribution of the reaction channels involving H-abstraction from the t-amyl group amounts to about 70% of the total rate coefficients. Using our calculated rate constants and a chosen OH tropospheric concentration of 1 × 106 molecule cm−3, lifetimes of ∼43 and ∼128 min were obtained for TAME and TAEE, respectively.

Background Several human-produced volatiles have been reported to mediate the host-seeking process under laboratory conditions, yet no effective lure or repellent has been developed for field application. Previously, we found a gradation of the attractiveness of foot odors of different malaria free individuals to Anopheles gambiae sensu stricto Giles. In this study, foot odor of the individual with the most attractive ‘smelly’ feet to the An. gambiae was collected, analyzed and attractive blend components identified. Methods The foot odor of the individual with the most attractive ‘smelly’ feet to the An. gambiae was trapped on Porapak Q and analyzed by gas chromatography-linked mass spectrometry (GC-MS). Specific constituents perceived by the insect olfactory system were then identified by GC-linked to electro-antennography detector (GC-EAD) and characterized by GC-MS. The contribution of each constituent to the behavioral response of An. gambiae was assessed through subtractive assays under semi-field conditions in a screen-house using Counter Flow Geometry (CFG traps) baited with (i) the blend of all the EAD-active and (ii) other blends containing all components with exclusion of one component at a time. The number of mosquitoes trapped in the baited CFG traps were compared with those in the control traps. Results Eleven major and minor constituents: 2 carboxylic acids, six aldehydes, two ketones and one phenolic compound, were confirmed to be EAD-active. The contribution of each constituent to the behavioral response of An. gambiae was assessed through subtractive assays under semi- field conditions. Exclusion/ subtraction of one of the following compounds: i-butyric acid, i-valeric acid, n-octanal, n-nonanal, n-decanal, n-dodecanal, undecanal or n-tridecanal, from each blend led to reduction in the attractiveness of all the resulting blends, suggesting that all of them are critical/important for the attractiveness of the foot odor to An. gambiae mosquitoes. However, exclusion/subtraction of 4-ethoxyacetophenone, 4-ethylacetophenone and/or 2-methylphenol, led to significant enhancements in the attractiveness of the resulting blends, suggesting that each of these compounds had repellent effect on An. gambiae ss. Undecanal exhibited kairomonal activity at low natural concentrations under semi-field conditions but repellent activity at high unnatural conditions in the laboratory. Furthermore, the comparison of the mean mosquito catches in traps baited with the nine-component blend without 4-ethoxyacetophenone, 4-ethylacetophenone and the complete foot odor collection revealed that the former is significantly more attractive and confirmed the repellent effect of the two carbonyl compounds at low natural concentration levels. Conclusion These results suggest that differential attractiveness of An. gambiae to human feet is due to qualitative and/or qualitative differences in the chemical compositions of the foot odors from individual human beings and relative proportions of the two chemical signatures (attractants versus repellents) as observed from the ratios of the bioactive components in the foot odors of the most attractive and least attractive individuals. Chemical signature means the ensemble of the compounds released by the organism in a specific physiological state. The chemical signature is emitter-dependent, but does not depend on receiver response. Thus, there is only one chemical signature for one individual or species that may eventually include inactive, attractive and repellent components for another organism. The nine-component attractive blend has a potential as an effective field bait for trapping of malaria vectors in human dwellings.

In Canada, the potato (Solanum tuberosum) is by far the most cultivated vegetable and plays a major nutritional role. However, during storage, the potato can easily undergo germination. In this study we have shown the inhibition potential of ethylene as an anti-germinative agent acting especially on phenols. In both varieties assayed (Yukon Gold and Russet Burbank) in this study, the ethylene treatment led to a decrease in total phenol concentration of about 20%. The analysis of potato extracts showed the decrease of specific phenol concentrations which was dependant on the time and temperature of extraction. Our hypothese that the transformation of phenols into phenolic ethyl ethers via possible radical mechanism were then formulated and confirmed by LC and LC/MS., Phenolic acids from Yukon Gold and Russet Burbank potatoes, Ethylenization of potato extracts, Inhibition of germination in potatoes (Solanum).

International audience; Surfactants are used in various applications: cosmetics, pharmaceuticals, petrochemicals, environmental, etc. Many of these compounds are polydisperse, and because of this intrinsic polydispersity, it is essential to have a universal detector with a uniform response to quantify them in a simple way. Indeed, Charged Aerosol Detector (CAD) was presented as a universal detector with a uniform response. Thus, in the present study, the CAD response, in a High-Performance Liquid Chromatography-CAD configuration (HPLC-CAD), was evaluated using purified alcohol ethoxylated surfactants. A semi-preparative liquid chromatography step using a Hydrophilic interaction chromatography (HILIC) bare silica column (150 mm, 4.6 mm, 2.6 µm) was implemented to prepare eleven homologues of BrijC10, a nonionic surfactant. These homologues differed only by the number of ethylene oxide units. BrijC10 homologues were analyzed by HPLC-CAD, using a HILIC bare silica column (150 mm, 2.1 mm, 2.6 µm) to determine the HPLC-CAD response factors of purified homologues. From the calibration curves (from 100 to 500 mg.kg-1), their response factors were estimated: differences in response factors were observed and a maximum difference in response factors of 3.6 was obtained. Thus, it could be concluded that CAD hyphenated to HILIC separation did not present a uniform response for this homologue's distribution.

Several drugs are currently in use as glutathione (GSH) enhancers in clinical, pre-clinical and experimental research. Here we compare the ability of N-acetylcysteine (NAC), 2-oxothiazolidine-4-carboxylic acid (OTC), glutathione ethyl ester (GSH-EE) and N-acetylcysteine ethyl ester (NACET) to increase the intracellular concentration of GSH using primary human umbilical vein endothelial cells (HUVEC) as in vitro model. Our experiments highlighted that NACET is largely the most efficient molecule in increasing the intracellular levels of GSH, cysteine, and γ-glutamylcysteine. This is because NACET is lipophilic and can freely cross plasma membrane but, inside the cell, it is de-esterified to the more hydrophilic NAC, which, in turn, is trapped into the cell and slowly transformed into cysteine. The higher availability of cysteine is matched by an increase in GSH synthesis, cysteine availability being the rate limiting step for this reaction. Surprisingly, the increase in GSH concentration was not linear but peaked at 0.5 mM NACET and gradually decreased when cells were treated with higher concentrations of NACET. We demonstrated that this puzzling ceiling effect was due to the fact that NAC released from NACET turned out to be a competitive inhibitor of the enzyme glutamate-cysteine ligase, with a Ki value of 3.2 mM. By using a cell culture medium lacking of cysteine and methionine, we could demonstrate that the slight increase in intracellular levels of cysteine and GSH induced by NAC in HUVEC grown in standard medium was due to the reduction of the cystine present in the medium itself there rather than to the action of NAC as Cys pro-drug. This fact may explain why NAC works well as GSH enhancer at very high concentrations in pre-clinical and in vitro studies, whereas it failed in most clinical trials.

Alkylidenemalonates have been subjected to dichlorocyclopropanation to produce novel spiro-gem-dichlorocyclopropylmalonates in quantitative yields. The latter have been reacted with urea in the presence of sodium ethoxide to produce the corresponding barbiturates in 80–95% yields. The cleavage of the spiro-gem-dichlorocyclopropylmalonate carbocycle with ethanol with the aid of aluminum chloride has led to ethyl ethers, while carbocycle expansion with isobutyraldehyde has afforded polysubstituted tetrahydrofurans. The prepared compounds have been structurally characterized in detail by 1H and 13C NMR spectroscopy.

Anhydrous alkali sulfide (M2S, M = Li and Na) nanocrystals (NCs) are important materials central to the development of next generation cathodes and solid state electrolytes for advanced batteries, but not commercially available at present. This work reports an innovative method to directly synthesize M2S-NCs through alcohol-mediated reactions between alkali metals and hydrogen sulfide (H2S). In the first step, the alkali metal is complexed with alcohol in solution, forming metal alkoxide (ROM) and releasing hydrogen (H2). Next, H2S is bubbled through the ROM solution, where both chemicals are completely consumed to produce phase-pure M2S-NC precipitates and regenerate alcohol that can be recycled. The M2S-NC morphology may be tuned through choice of the alcohol and the solvent. Both synthetic steps are thermodynamically favorable (∆Gmo M2S + H2, makes good use of a hazardous chemical H2S and delivers two value-added products that naturally phase separate for easy recovery. This scalable approach provides an energy-efficient and environmentally-benign solution to the production of nanostructured materials required in emerging battery technologies.

This review summarises the current state of knowledge on the biodegradation and fate of the gasoline ether oxygenate ethyl tert-butyl ether (ETBE) in soil and groundwater. Microorganisms have been identified in soil and groundwater with the ability to degrade ETBE aerobically as a carbon and energy source, or via cometabolism using alkanes as growth substrates. Aerobic biodegradation of ETBE initially occurs via hydroxylation of the ethoxy carbon by a monooxygenase enzyme, with subsequent formation of intermediates which include acetaldehyde, tert-butyl acetate (TBAc), tert-butyl alcohol (TBA), 2-hydroxy-2-methyl-1-propanol (MHP) and 2-hydroxyisobutyric acid (2-HIBA). Slow cell growth and low biomass yields on ETBE are believed to result from the ether structure and slow degradation kinetics, with potential limitations on ETBE metabolism. Genes known to facilitate transformation of ETBE include ethB (within the ethRABCD cluster), encoding a cytochrome P450 monooxygenase, and alkB-encoding alkane hydroxylases. Other genes have been identified in microorganisms but their activity and specificity towards ETBE remains poorly characterised. Microorganisms and pathways supporting anaerobic biodegradation of ETBE have not been identified, although this potential has been demonstrated in limited field and laboratory studies. The presence of co-contaminants (other ether oxygenates, hydrocarbons and organic compounds) in soil and groundwater may limit aerobic biodegradation of ETBE by preferential metabolism and consumption of available dissolved oxygen or enhance ETBE biodegradation through cometabolism. Both ETBE-degrading microorganisms and alkane-oxidising bacteria have been characterised, with potential for use in bioaugmentation and biostimulation of ETBE degradation in groundwater.

In cancer bioassays, inhalation, but not drinking water exposure to ethyl tertiary‐butyl ether (ETBE), caused liver tumors in male rats, while tertiary‐butyl alcohol (TBA), an ETBE metabolite, caused kidney tumors in male rats following exposure via drinking water. To understand the contribution of ETBE and TBA kinetics under varying exposure scenarios to these tumor responses, a physiologically based pharmacokinetic model was developed based on a previously published model for methyl tertiary‐butyl ether, a structurally similar chemical, and verified against the literature and study report data. The model included ETBE and TBA binding to the male rat‐specific protein α2u–globulin, which plays a role in the ETBE and TBA kidney response observed in male rats. Metabolism of ETBE and TBA was described as a single, saturable pathway in the liver. The model predicted similar kidney AUC0–∞ for TBA for various exposure scenarios from ETBE and TBA cancer bioassays, supporting a male‐rat‐specific mode of action for TBA‐induced kidney tumors. The model also predicted nonlinear kinetics at ETBE inhalation exposure concentrations above ~2000 ppm, based on blood AUC0–∞ for ETBE and TBA. The shift from linear to nonlinear kinetics at exposure concentrations below the concentration associated with liver tumors in rats (5000 ppm) suggests the mode of action for liver tumors operates under nonlinear kinetics following chronic exposure and is not relevant for assessing human risk. Copyright © 2016 The Authors Journal of Applied Toxicology Published by John Wiley & Sons Ltd, Inhalation, but not drinking‐water exposure, to a high concentration of ethyl tertiary butyl ether was reported to cause liver tumors in male rats. Using a PBPK model for ethyl tertiary butyl ether and its metabolite tertiary butyl alcohol, under cancer bioassay exposure scenarios, showed a shift from linear to nonlinear kinetics at the exposure concentration associated with liver tumors. This suggests that a liver tumor mode of action that occurs under a high exposure concentration is not relevant for assessing human risk.

Several new energetic ethyl ethers of 1,2,4,5-tetrazine have been synthesized. These molecules display good thermal stability, good oxygen balance, and high densities. Included in these studies are a 2,2,2-trinitroethoxy 1,2,4,5-tetrazine and two fluorodinitroethoxy 1,2,4,5-tetrazines. One of these compounds was converted into the di-N-oxide derivative. The sensitivity of these materials towards destructive stimuli was determined, and overall the materials show promising energetic performance properties.

The production of biofuel has increased considerably over the last years. Glycerol, a by-product of biodiesel synthesis, accounts for about 10 wt% of the total mass balance in the transesterification process and has a limited range of applications. The acid-catalyzed etherification of glycerol with alcohols could be an attractive solution to address the excess of glycerol. This study is focused on the etherification of glycerol with ethanol over solid acid catalysts, such as zeolites, clays and sulfonic resins. All the catalysts produced mono, di and tri-glycerol-ethers that can be used as biodiesel fuel components. Higher conversion and selectivity to ethyl glyceryl ethers were obtained at 180 °C, ethanol/glycerol molar ratio of 3:1 and 4 h of reaction time, with Amberlyst-15 acid resin as catalyst. Under these reaction conditions, 96% of glycerol conversion and 80% selectivity to the ethyl ethers were observed. Laboratory tests using a blend containing 0.5–1.0 vol% of the ethyl glyceryl ethers in biodiesel showed reduction of pour and cloud points, indicating the potential of these ethers as bioadditives to fuels.

Aerobic biodegradation of ethyl tert butyl ether (ETBE) in a gasoline-impacted aquifer was investigated in laboratory microcosms containing groundwater and aquifer material from ETBE-impacted and non-impacted locations amended with either ETBE, or ETBE plus methyl tert butyl ether (MTBE). As sole substrate, ETBE was biodegraded (maximum rate of 0.54 day-1) without a lag in ETBE-impacted microcosms but with a lag of up to 66 days in non-impacted microcosms (maximum rate of 0.38 day-1). As co-substrate, ETBE was biodegraded preferentially (maximum rate of 0.25 and 0.99 day-1 in non-impacted and impacted microcosms, respectively) before MTBE (maximum rate of 0.24 and 0.36 day-1 in non-impacted and impacted microcosms, respectively). Further addition of ETBE and MTBE reduced lags and increased biodegradation rates. ethB gene copy numbers increased significantly (>100 fold) after exposure to ETBE, while overall cell numbers remained constant, suggesting that ethB-containing microorganisms come to dominate the microbial communities. Deep sequencing of 16S rRNA genes identified members of the Comamonadaceae family that increased in relative abundance upon exposure to ETBE. This study demonstrates the potential for ETBE biodegradation within the unsaturated and saturated zone, and that ETBE biodegrading capability is rapidly developed and maintained within the aquifer microbial community over extended timescales.

Owing to dopamine's excellent adhesion ability and easy modification, it has been widely applied for enzyme immobilization, while the high cost of dopamine and low activity recovery of immobilized enzyme highly impede large-scale application of immobilized enzyme. We herein developed a low-cost and ideal activity recovery enzyme immobilization strategy based on magnetic nanoparticles by replacing dopamine with cheap Catechol/tetraethylene pentamine (CPA) binary system and introducing spacer-arms. In brief, CPA was first polymerized and deposited on the surface of magnetic nanoparticles with a modified mussel-inspired method, and the generated poly(CPA) layer was further functionalized with ethylene glycol diglycidyl ether (EGDE) molecules as spacer-arms for enzyme immobilization. Subsequently, lipases as model enzymes were firmly immobilized on the surface of such amino-epoxy functionalized magnetic materials through ion exchange and covalent attachment with 180.6 mg/g support of loading capacity and 69.2% of activity recovery under the optimized conditions. Furthermore, the immobilized lipase exhibited the improved tolerance rang of pH, temperature and storage stability as well as excellent reusability. Most strikingly, the theoretical simulation and secondary structure analysis of immobilized lipase revealed that the biocompatible microenvironment and flexible tethering at interface could effectively improve performance of the immobilized enzyme and stability. Thus, this novel immobilized enzyme strategy will open up a new perspective for the development of enzyme immobilization and lower the cost of immobilized enzyme in large-scale industrial application.

Background Biomarkers of alcohol consumption are important not only in forensic contexts, e.g., in child custody proceedings or as documentation of alcohol abstinence after temporary confiscation of a driver's license. They are increasingly being used in clinical medicine as well for verification of abstinence or to rule out the harmful use of alcohol. Methods This review is based on pertinent publications that were retrieved by a selective literature search in PubMed concerning the direct and indirect alcohol markers discussed here, as well as on the authors' experience in laboratory analysis and clinical medicine. Results Alongside the direct demonstration of ethanol, the available markers of alcohol consumption include the classic indirect markers carbohydrate-deficient transferrin (CDT), gamma-glutamyltransferase (GGT), and mean corpuscular volume (MCV) as well as direct alcohol markers such as ethyl glucuronide (EtG) and ethyl sulfate (EtS) in serum and urine and EtG and fatty acid ethyl esters (FAEE) in hair. Phosphatidylethanol (PEth) is a promising parameter that com - plements the existing spectrum of tests with high specificity (48-89%) and sensi - tivity (88-100%). In routine clinical practice, the demonstration of positive alcohol markers often leads patients to admit previously denied alcohol use. This makes it possible to motivate the patient to undergo treatment for alcoholism. Conclusion The available alcohol biomarkers vary in sensitivity and specificity with respect to the time period over which they indicate alcohol use and the minimum extent of alcohol use that they can detect. The appropriate marker or combination of markers should be chosen in each case according to the particular question that is to be answered by laboratory analysis.

The single most common cause of chronic pancreatitis (CP, a serious inflammatory disease) is chronic alcohol abuse, which impairs hepatic alcohol dehydrogenase (ADH, a major ethanol oxidizing enzyme). Previously, we found ~5 fold greater fatty acid ethyl esters (FAEEs), and injury in the pancreas of hepatic ADH deficient (ADH-) vs. hepatic normal ADH (ADH+) deer mice fed 3.5g% ethanol via liquid diet daily for two months. Therefore, progression of ethanol-induced pancreatic injury was determined in ADH- deer mice fed ethanol for four months to delineate the mechanism and metabolic basis of alcoholic chronic pancreatitis (ACP). In addition to a substantially increased blood alcohol concentration and plasma FAEEs, significant degenerative changes, including atrophy and loss of acinar cells in some areas, ultrastructural changes evident by such features as swelling and disintegration of endoplasmic reticulum (ER) cisternae and ER stress were observed in the pancreas of ethanol-fed ADH- deer mice vs. ADH+ deer mice. These changes are consistent with noted increases in pancreatic injury markers (plasma lipase, pancreatic trypsinogen activation peptide, FAEE synthase and cathepsin B) in ethanol-fed ADH- deer mice. Most importantly, an increased levels of pancreatic glucose regulated protein (GRP) 78 (a prominent ER stress marker) were found to be closely associated with increased phosphorylated eukaryotic initiation factor (eIF) 2α signaling molecule in PKR-like ER kinase branch of unfolded protein response (UPR) as compared to X box binding protein 1S and activating transcription factor (ATF)6 - 50kDa protein of inositol requiring enzyme 1α and ATF6 branches of UPR, respectively, in ethanol-fed ADH- vs. ADH+ deer mice. These results along with findings on plasma FAEEs, and pancreatic histology and injury markers suggest a metabolic basis of ethanol-induced pancreatic injury, and provide new avenues to understand metabolic basis and molecular mechanism of ACP.

Subchronic and chronic studies in rats of the gasoline oxygenates ethyl tert-butyl ether (ETBE) and tert-butanol (TBA) report similar noncancer kidney and liver effects but differing results with respect to kidney and liver tumors. Because TBA is a major metabolite of ETBE, it is possible that TBA is the active toxic moiety in all these studies, with reported differences due simply to differences in the internal dose. To test this hypothesis, a physiologically-based pharmacokinetic (PBPK) model was developed for ETBE and TBA to calculate internal dosimetrics of TBA following either TBA or ETBE exposure. This model, based on earlier PBPK models of methyl tert-butyl ether (MTBE), was used to evaluate whether kidney and liver effects are consistent across routes of exposure, as well as between ETBE and TBA studies, on the basis of estimated internal dose. The results demonstrate that noncancer kidney effects, including kidney weight changes, urothelial hyperplasia, and chronic progressive nephropathy (CPN), yielded consistent dose-response relationships across routes of exposure and across ETBE and TBA studies using TBA blood concentration as the dose metric. Relative liver weights were also consistent across studies on the basis of TBA metabolism, which is proportional to TBA liver concentrations. However, kidney and liver tumors were not consistent using any dose metric. These results support the hypothesis that TBA mediates the noncancer kidney and liver effects following ETBE administration; however, additional factors besides internal dose are necessary to explain the induction of liver and kidney tumors.

Nanoparticles (NPs) have received much attention in recent years for their diverse potential biomedical applications. However, the synthesis of NPs with desired biodistribution and pharmacokinetics is still a major challenge, with NP size and surface chemistry being the main factors determining the behavior of NPs in vivo. Here we report on the surface chemistry and in vitro cellular uptake of magnetic iron oxide NPs coated with zwitterionic dopamine sulfonate (ZDS). ZDS-coated NPs were compared to similar iron oxide NPs coated with PEG-like 2-[2-(2-methoxyethoxy)ethoxy]acetic acid (MEEA) to investigate how surface chemistry affects their in vitro behavior. ZDS-coated NPs had a very dense coating, guaranteeing high colloidal stability in several aqueous media and negligible interaction with proteins. Treatment of HepG2 cells with increasing doses (2.5-100 mug Fe/mL) of ZDS-coated iron oxide NPs had no effect on cell viability and resulted in a low, dose-dependent NP uptake, inferior than most reported data for the internalization of iron oxide NPs by HepG2 cells. MEEA-coated NPs were scarcely stable and formed micrometer-sized aggregates in aqueous media. They decreased cell viability for dose >=50 mug Fe/mL, and were more efficiently internalized than ZDS-coated NPs. In conclusion, our data indicate that the ZDS layer prevented both aggregation and sedimentation of iron oxide NPs and formed a biocompatible coating that did not display any biocorona effect. The very low cellular uptake of ZDS-coated iron NPs can be useful to achieve highly selective targeting upon specific functionalization.

BACKGROUND Human hair is a well-validated matrix for detecting a variety of xenobiotics, including drugs of abuse (cocaine, tetrahydrocannabinol, and morphine) and fatty acid ethyl ethers. Recent studies have shown that hair can also be useful in determining an individual's exposure to polybrominated diphenyl ethers (PBDEs), flame retardants that contaminate the dust in our daily environment. Hair processing before assay varies with each analyte; in particular, the wash protocol must be optimized to remove external contaminants while not affecting levels of the chemical of interest. The aim of this study was to determine whether hair needs to be washed before analysis for PBDEs, and if so, which protocol is most effective to ensure that the level of PBDEs is neither overestimated nor underestimated. METHOD Individual hair samples from 10 adults (5 men and 5 women) were subjected to 4 different wash protocols: (1) no wash, (2) water, (3) 10% sodium dodecyl sulfate (SDS), and (4) hexane. Both the washes and hair were analyzed for 8 PBDEs by gas chromatography/mass spectrometry. RESULTS The sum of PBDEs (ΣPBDEs) in the washes was (1) no wash: 0 pg/mg, (2) water: 0.39 ± 0.19 (mean ± SEM), (3) 10% SDS: 1.34 ± 0.68, and (4) hexane: 1.92 ± 0.87. The ΣPBDEs in the hair were: (1) no wash: 20.32 ± 3.05, (2) water: 20.30 ± 2.41, (3) 10% SDS: 19.27 ± 1.87, and (4) hexane: 16.91 ± 2.89. Washing with water, 10% SDS, and hexane decreased the PBDE levels by 1.9%, 7%, and 11.4%, respectively (P < 0.05). CONCLUSIONS Thus, of the washes evaluated, water is the wash that had the least effect on total PBDE concentrations, providing the best evaluation of an individual's exposure to PBDEs.

As one of the most important biomass platform molecules, ethanol needs to have its product chain chemically extended to meet future demands in renewable fuels and chemicals. Additionally, chemical conversion of ethanol under mild and green conditions is still a major challenge. In this work, ethanol is directly converted into 1,1-diethoxyethane (DEE) and H2 under mild photocatalytic conditions over platinum-loaded TiO2 nanotubes and nanorods. The reaction follows a tandem dehydrogenation-acetalization mechanism, in which ethanol is first dehydrogenated into acetaldehyde and H(+) ion by photogenerated holes, and then acetalization between acetaldehyde and ethanol proceeds through promotion by H(+) ions formed in real time. Excess H(+) ions are simultaneously reduced into H2 by photogenerated electrons. This photocatalytic process has a very high reaction rate over nanosized tubular and rod-like TiO2 photocatalysts, reaching 157.7 mmol g(-1) h(-1) in relatively low photocatalyst feeding. More importantly, the reaction is highly selective, with a nearly stoichiometric conversion of reacted ethanol into DEE. This photocatalytic dehydrogenation CO coupling of ethanol is a new green approach to the direct efficient conversion of ethanol into DEE and provides a promising channel for sustainable bioethanol applications.

Following a systematic search of desferrithiocin analogs, a polyether derivative, deferitazole (formerly FBS0701), has entered into phase 1 and 2 clinical trials with promising biological properties. However, until now, detailed physicochemical properties of this chelator have not been reported. The compound displays a high affinity and selectivity for iron(III) as demonstrated by the log β2 = 33.39 ± 0.03 and the pFe(3+) value of 22.3. Two equilibrating isomeric forms of the iron(III) complex exist under biological conditions. Deferitazole also binds the trivalent metals Al(III) and La(III) with high affinity; log β2 values, 26.68 and 21.55 respectively. The affinity of deferitazole for divalent cations is somewhat lower, with the exception of Cu(II) which possesses a log β2 value of 25.5; deferitazole scavenges iron from labile sources such as citrate and albumin with efficiencies comparable with those of other therapeutic iron chelators, including deferasirox, deferiprone and desferrioxamine. The Fe(III)(deferitazole)2 is stable under physiological conditions and does not redox cycle. The high affinity of deferitazole for iron(III) renders it unlikely that this chelator will lead to the redistribution of iron and consequently deferitazole shows considerable promise as a therapeutic iron(III) chelator.

Fatty acid ethyl esters (FAEE) are direct metabolites of ethanol and have been shown to be suitable markers for the evaluation of alcohol consumption. Previous research has suggested that the regular use of alcohol containing cosmetic products can influence the concentration of FAEE detected in hair. In this study we investigated the influence of alcohol containing and alcohol free hair cosmetics (hairspray and waxes) on the FAEE concentrations in hair. The effect of cosmetic treatment was measured against the impact on ethyl palmitate in isolation as compared to the sum of four esters. 10 volunteers treated part of their scalp with cosmetic products every day during a 2 month period (alcohol free hairspray n=2, hairspray containing alcohol (42% by volume) n=3, alcohol free wax n=2, wax containing alcohol (11% by volume) n=3). After the 2 month period of cosmetic application hair samples from volunteers were collected from both sides of the scalp. Hair samples were washed with n-heptane, and then cut finely into small pieces. All samples were subjected to clean-up by HS-SPME and then GC PCI-MS/MS for analysis of FAEEs. Comparison of FAEE concentrations between treated and untreated hair showed in some instances that application of hair spray or wax products caused an increase in FAEE levels. Products containing alcohol caused a more substantial increase in alcohol metabolite concentrations in hair when compared to alcohol free products. Three volunteers using an alcohol based hairspray in the study experienced a significant increase in FAEE levels (+27.4%, +205.5%, and +1287.5%), with one of the volunteers showing levels below the cut off for 'abstinence' in the untreated scalp portion, and levels above the cut off for 'chronic excessive consumption' in the treated scalp portion. Performance evaluation of ethyl palmitate as sole marker, compared to the sum of four esters approach suggested that the two quantification approaches react in a very similar manner to the application of hair sprays and waxes. We would suggest that the interpretative value of FAEE hair measurements from people reporting the use of alcohol based hairsprays are treated with caution.

This paper reports the efficient synthesis of the first class of polyisobutylene(PIB)-supported palladium-PEPPSI precatalyst (PEPPSI = pyridine-enhanced precatalyst preparation, stabilization, and initiation). The new complexes are employed in Buchwald–Hartwig amination of aryl chlorides and are found to be reasonably active in the titled cross-coupling reaction. The supported catalysts are tested in polar (1,4-dioxane and 1,2-dimethoxyethane) as well as in aliphatic reaction media (toluene and n-heptane) and display superior activity in the highly lipophilic solvent (n-heptane). The catalytic efficacy of PIB-Pd-PEPPSI precatalyst is measured to be comparable to its nonsupported analog. Pd-leaching is determined by inductively coupled plasma mass spectrometry (ICP-MS) after a simple liquid/liquid extraction and is found to be 2 ppb in the product phase, translating into a recovery of ≈99.8% of the palladium.

The ethers produced through the etherification reaction of glycerol with ethanol or t-butanol are used as oxygenated fuel additives, intermediates in the pharmaceutical industry, and non-ionic surfactants. However, the identification of these ethers has not been accurately done, because only some mass spectra of these compounds are available in the libraries. Moreover, there is a lack of discussion on their identification in the literature. In this work, a detailed identification of all ethers produced in the etherification of glycerol with ethanol or t-butanol was performed considering the mass spectra of isolated products and the comparison of the retention times. The elution order of the products was: tri-alkyl, 1,3-dialkyl, 2,3-dialkyl, 3-monoalkyl and 2-monoalkyl. In all mass spectra of the ethyl ethers, the base peak was m/z 61, while in the case of t-butyl ethers it was m/z 57.

The hydroxylation reactions of ethyl vinyl ether (EVE) in the present of O2 and NO are analyzed by using MPWB1K/6-311++G(3df,2p)//MPWB1K/6-31+G(d,p) level of theory. According to the calculated thermodynamic data, the detailed reaction mechanisms of EVE and OH are proposed. All of the ten possible reaction pathways are discussed. The major products of the title reaction are ethyl formate and formaldehyde, which is in accordance with experimental detection. The rate constants of the primary reactions over the temperature of 250-400K and the pressure range of 100-2000Torr are computed by employing MESMER program. At 298K and 760Torr, OH-addition channels are predominate and the total rate constant is ktot=4.53×10(-11)cm(3)molecule(-1)s(-1). The Arrhenius equation is obtained as ktot=6.27×10(-12)exp(611.5/T), according to the rate constants given at different temperatures. Finally, the atmospheric half life of EVE with respect to OH is estimated to be 2.13h.

International audience; The ethyl tert-butyl ether (ETBE) degradation capacity and phylogenetic composition of five aerobic enrichment cultures with ETBE as the sole carbon and energy source were studied. In all cases, ETBE was entirely degraded to biomass and CO2. Clone libraries of the 16S rRNA gene were prepared from each enrichment. The analyses of the DNA sequences obtained showed different taxonomic compositions with a majority of Proteobacteria in three cases. The two other enrichments have different microbiota with an abundance of Acidobacteria in one case, whereas the microbiota in the second was more diverse (majority of Actinobacteria, Chlorobi and Gemmatimonadetes). Actinobacteria were detected in all five enrichments. Several bacterial strains were isolated from the enrichments and five were capable of degrading ETBE and/or tert-butyl alcohol (TBA), a degradation intermediate. The five included three Rhodococcus sp. (IFP 2040, IFP 2041, IFP 2043), one Betaproteobacteria (IFP 2047) belonging to the Rubrivivax/Leptothrix/Ideonella branch, and one Pseudonocardia sp. (IFP 2050). Quantification of these five strains and two other strains, Rhodococcus sp. IFP 2042 and Bradyrhizobium sp. IFP2049, which had been previously isolated from one of the enrichments was carried out on the different enrichments based on quantitative PCR with specific 16S rRNA gene primers and the results were consistent with the hypothesized role of Actinobacteria and Betaproteobacteria in the degradation of ETBE and the possible role of Bradyrhizobium strains in the degradation of TBA.

The development of new protecting groups that undergo neighbouring group participation (NGP) via six-membered ring intermediates to promote the formation of α-1,2-cis glycosidic linkages complements the established use of 5-ring NGP in terms of stereochemical outcome. A selection of glycosyl donors was synthesised that possessed novel 2-iodo- and 2-(phenylseleno)ethyl ether protecting groups in an attempt to promote highly α-selective glycosylation by 6-ring NGP. Although the fully armed donors produced α-glucosides as the predominant reaction products, low-temperature NMR studies did not show NGP by the observation of cyclised reaction intermediates. The corresponding disarmed glycosyl donors were unexpectedly less stereoselective. NMR spectroscopy revealed that the 2-iodoethyl ether did not participate in any of the glycosylation processes; however, the 2-(phenylseleno)ethyl ether did participate, and β-configured cyclic intermediates were observed. The fact that considerable amounts of β-glycoside product were formed in these latter cases indicated that the predominant reaction pathway to product did not occur through the observed cyclic species. Clearly, a fine balance exists during glycosylation reactions, and the reaction pathway to product depends on a variety of factors. Notably, the formation of cyclised intermediates by 6-ring NGP is not on its own sufficient to ensure high levels of α-stereoselectivity.

A rapid and relatively clean method for determining six organotin compounds (OtC) in textile goods with a gas chromatograph equipped with a conventional flame photometric detector (GC-FPD) has been developed. After the reflux-extraction to use methanol containing 1% (v/v) of hydrochloric acid, five hydrophobic OtC (e.g. tributyltin: TBT) and slightly less hydrophobic dibutyltin (DBT) could be drawn out through partitioning between the methanolic buffer solution and tert-butyl ethyl ether instead of hazardous dichloromethane, of which usage is provided by the official-methods notified in Japan, and following the ethylation procedure to use sodium tetraethylborate, the OtC were determined with the GC-FPD. The recoveries of DBT, TBT, tetrabutyltin, triphenyltin, dioctyltin, and trioctyltin from textile products (cloth diaper, socks, and undershirt) were 60–77, 89–98, 86–94, 71–78, 85–109, and 70–79% respectively, and their coefficients of variation were 2.5–16.5%. Calibration curves for OtC were linear (0.01–0.20 μg as Sn mL−1), and the correlation coefficients were 0.9922–1.0000. Their detection limits were estimated to be 2.7–9.7 ng as Sn g−1. These data suggested that this method would be applicable to their simultaneous determination. Five retailed textile goods were analyzed by this proposed method, and 0.013–0.65 µg as Sn g−1 of OtC (e.g. DBT) were determined in three. Moreover, a possibility that various OtC including non-targeted species in textile would be specifically detected by applying the studying speciation-technique of controlling signal intensity-flame fuel gas pressures of the GC-FPD was found.

Ethyl tertiary butyl ether (ETBE) is biofuel additive recently used in Japan and some other countries. Limited evidence shows that ETBE has low toxicity. Acetaldehyde (AA), however, as one primary metabolite of ETBE, is clearly genotoxic and has been considered to be a potential carcinogen. The aim of this study was to evaluate the effects of ALDH2 gene on ETBE-induced genotoxicity and metabolism of its metabolites after inhalation exposure to ETBE. A group of wild-type (WT) and Aldh2 knockout (KO) C57BL/6 mice were exposed to 500 ppm ETBE for 1–6 h, and the blood concentrations of ETBE metabolites, including AA, tert-butyl alcohol and 2-methyl-1,2-propanediol, were measured. Another group of mice of WT and KO were exposed to 0, 500, 1750, or 5000 ppm ETBE for 6 h/day with 5 days per weeks for 13 weeks. Genotoxic effects of ETBE in these mice were measured by the alkaline comet assay, 8-hydroxyguanine DNA-glycosylase modified comet assay and micronucleus test. With short-term exposure to ETBE, the blood concentrations of all the three metabolites in KO mice were significantly higher than the corresponding concentrations of those in WT mice of both sexes. After subchronic exposure to ETBE, there was significant increase in DNA damage in a dose-dependent manner in KO male mice, while only 5000 ppm exposure significantly increased DNA damage in male WT mice. Overall, there was a significant sex difference in genetic damage in both genetic types of mice. These results showed that ALDH2 is involved in the detoxification of ETBE and lack of enzyme activity may greatly increase the sensitivity to the genotoxic effects of ETBE, and male mice were more sensitive than females.

Fuel oxygenates are environmentally detrimental compounds due to their rapid migration to groundwater. Fuel oxygenates have been reported to cause taste and odour problems in drinking water, and they also have long-term health effects. Feasible analytical methods are required to observe the presence of fuel oxygenates in drinking and natural water. The authors studied ion mobility spectrometry (IMS) to determinate isomeric fuel ether oxygenates; ethyl tert-butyl ether (ETBE), diisopropyl ether (DIPE), and tert-amyl methyl ether (TAME), separated from aqueous matrices with a pervaporation membrane module. Methyl tert-butyl ether (MTBE) was also membrane extracted and detected with IMS. The authors demonstrated that fuel ethers (MTBE, ETBE, DIPE, and TAME) can be quantified at μg/L level with membrane extraction IMS. A membrane extraction module coupled to IMS is a time and cost effective analysis method because sampling can be performed in a single procedure and from different natural water matrices within a few minutes. Consequently, IMS combined with membrane extraction is suitable not only for waterworks and other online applications but also in the field monitoring the quality of drinking and natural water.

Glymes (i.e. glycol diethers) were explored as alternative benign solvents for enzymatic reactions, specifically the lipase-catalyzed transesterification. Long-chain glymes were found highly compatible with immobilized Candida antarctica lipase B (iCALB), leading to higher enzyme activities and stabilities than t-butanol and ionic liquids (e.g. the rate of transesterification in diethylene glycol dibutyl ether (G2-Bu) was 77% higher than that in t-butanol). Furthermore, soybean oil was found fully miscible with glymes, which enabled a homogeneous reaction mixture for the enzymatic preparation of biodiesel. In the presence of glymes, CALB showed a very high tolerance to high methanol concentrations (up to 60–70% v/v), and nearly stoichiometric triglyceride conversions could be obtained under mild reaction conditions. A laboratory scale-up achieved a high conversion of soybean oil (95.5%). This study suggests that glymes can be environmentally friendly and inexpensive solvents for lipase-catalyzed reactions, such as the enzymatic preparation of biodiesel.

Fatty acid ethyl esters (FAEEs) have been widely studied as specific markers of ethanol intake and mediators of ethanol-induced diseases. In the present study, a simple and rapid gas chromatography-mass spectrometry (GC-MS) method was established for the qualitative and quantitative analysis of six fatty acid ethyl esters (FAEEs), including ethyl myristate, ethyl palmitate, ethyl stearate, ethyl oleate, ethyl linoleate, and ethyl arachidonate, in human whole blood. FAEEs were extracted from 200 μL of human whole blood by a modified liquid-liquid extraction, and the hexane layer was injected directly into GC-MS with ethyl heptadecanoate as the internal standard. The limits of detection (LODs) and limits of quantification (LOQs) were in the range of 5–50 ng/mL and 15–200 ng/mL, respectively. Linearity ranged up to 10 μg/mL with r 2 higher than 0.998. Accuracy was in the range of 90.3–109.7%, while intra-day and inter-day precision were 0.7–9.3% and 3.4–12.5%, respectively. This method was then applied to 38 real samples from forensic cases. Differences in the most common FAEEs between Chinese and Western subjects were discussed. The relationship of FAEE concentrations with age and gender was also investigated.

In this work, the ethanolysis of triglycerides catalyzed by immobilized lipase was studied, focusing on the secondary reaction of acyl migration. The catalytic tests were performed in a solvent-free reaction medium using Novozym 435 as biocatalyst. The selected experimental variables were biocatalyst loading (5-20 mg), reaction time (30-90 min), and chain length of the fatty acids in triglycerides with and without unsaturation (short (triacetin), medium (tricaprylin) and long (tripalmitin/triolein)). The formation of 2-monoglyceride by ethanolysis of triglycerides was favored by long reaction times and large biocatalyst loading with saturated short- to medium-chain triglycerides. In the case of long-chain triglycerides, the formation of this monoglyceride was widely limited by acyl migration. In turn, acyl migration increased the yield of ethyl esters and minimized the content of monoglycerides and diglycerides. Thus, the enzymatic synthesis of biodiesel was favored by long-chain triglycerides (which favor the acyl migration), long reaction times and large biocatalyst loading. The conversion of acylglycerides made from long-chain fatty acids with unsaturation was relatively low due to limitations in their access to the active site of the lipase. Fil: Sanchez, Daniel Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina Fil: Tonetto, Gabriela Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina Fil: Ferreira, María Luján. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina

a b s t r a c t Gasoline additives ethyl tert butyl ether (ETBE) and tertiary amyl methyl ether (TAME) are used world wide, but the consequence of developmental exposure to these hydrophilic chemicals is unknown for aquatic vertebrates. The effect of ETBE and TAME on zebrafish embryos was determined following OECD 212 guidelines, and their toxicity was compared to structurally related methyl tert-butyl ether (MTBE), which is known to target developing vasculature. LC50s for ETBE and TAME were 14 mM (95% CI = 10-20) and 10 mM (CI = 8-12.5), respectively. Both chemicals caused dose dependent developmental lesions (0.625-10 mM), which included pericardial edema, abnormal vascular development, whole body edema, and craniofacial abnormalities. The lesions were suggestive of a dysregulation of WNT ligands and matrix metalloproteinase (MMP) protein families based on their roles in development. Exposure to 5 mM ETBE significantly (p ≤ 0.05) decreased relative mRNA transcript levels of mmp-9 and wnt3a, while 2.5 and 5 mM TAME significantly decreased wnt3a, and wnt8a. TAME also significantly decreased mmp-2 and -9 mRNA levels at 5 mM. ETBE and TAME were less effective in altering the expression of vascular endothe- lial growth factor-a and -c, which were the only genes tested that were significantly decreased by MTBE. This is the first study to characterize the aquatic developmental toxicity following embryonic expo- sure to ETBE and TAME. Unlike MTBE, which specifically targets angiogenesis, ETBE and TAME disrupt multiple organ systems and significantly alter the mRNA transcript levels of genes required for general development.

This article presents results from 1872 hair samples, which were analyzed for fatty acid ethyl esters (FAEEs) and ethyl glucuronide (EtG). The results were evaluated in the context of self-reported drinking behavior, the use of hair cosmetics, the gender of the sample donors and hair sample length. For comparison, CDT and GGT in serum were available in 477 and 454 cases, respectively. A number of alcohol abstainers or low moderate drinkers and excessive drinkers were selected for assessment of cut-offs for FAEEs in the proximal 6cm hair segments and for EtG in the proximal 3cm hair segments. Cut-off values were assessed by ROC analysis. It was found that the cut-offs of 1.0ng/mg FAEE and 30pg/mg EtG presently used for excessive drinking lead to a low portion of false positives (4% and 3% respectively) but to a higher portion of false negatives (23% and 25% respectively). Comparison of the mean and medium concentrations in samples without any reported hair cosmetics (N=1079) and in samples with reported use of hair spray (N=79) showed an increase by the factor of about two for FAEE but no significant difference for EtG. Mean values of EtG were decreased by 80% in bleached samples (N=164) and by 63% in dyed samples (N=96). There was no significant effect of bleaching and dyeing on FAEE. Hair gel and hair wax, oil or grease showed no significant effect on both FAEE and EtG. With respect to gender and investigated hair length ambiguous results were obtained because of major differences in the compared subpopulations of male with higher alcohol consumption and mainly shorter hair, and less drinking female with longer hair. For excessive drinkers FAEEs in the 0-6cm hair segment and EtG in the 0-3cm segment decreased with increasing time of reported abstinence before sample collection. These drinkers attain the level of teetotalers only after more than 10 months of abstinence. In comparison to scalp hair, FAEEs recovered from armpit hair and leg hair were lower and from chest hair were higher. EtG in armpit hair was lower and in leg hair higher than in scalp hair. It is concluded that the combined use of FAEE and EtG essentially increases the accuracy of interpretation since both markers complement each other by a different sensitivity to sources of error.

Although the uniform initial hydroxylation of methyl tert-butyl ether (MTBE) and other oxygenates during aerobic biodegradation has already been proven by molecular tools, variations in carbon and hydrogen enrichment factors (ε(C) and ε(H)) have still been associated with different reaction mechanisms (McKelvie et al. Environ. Sci. Technol. 2009, 43, 2793-2799). Here, we present new laboratory-derived ε(C) and ε(H) data on the initial degradation mechanisms of MTBE, ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME) by chemical oxidation (permanganate, Fenton reagents), acid hydrolysis, and aerobic bacteria cultures (species of Aquincola, Methylibium, Gordonia, Mycobacterium, Pseudomonas, and Rhodococcus). Plotting of Δδ(2)H/ Δδ(13)C data from chemical oxidation and hydrolysis of ethers resulted in slopes (Λ values) of 22 ± 4 and between 6 and 12, respectively. With A. tertiaricarbonis L108, R. zopfii IFP 2005, and Gordonia sp. IFP 2009, ε(C) was low (|-1|‰) and ε(H) was insignificant. Fractionation obtained with P. putida GPo1 was similar to acid hydrolysis and M. austroafricanum JOB5 and R. ruber DSM 7511 displayed Λ values previously only ascribed to anaerobic attack. The fractionation patterns rather correlate with the employment of different P450, AlkB, and other monooxygenases, likely catalyzing ether hydroxylation via different transition states. Our data questions the value of 2D-CSIA for a simple distinguishing of oxygenate biotransformation mechanisms, therefore caution and complementary tools are needed for proper interpretation of groundwater plumes at field sites.

In this paper, a theoretical study of 1,2-dimethoxyethane (DME) and 1,2-dimethoxypropane (DMP) at water/n-heptane and 1,2-dimyristoyl-sn-glycero-3- phospatidycholine (DMPC) lipid bilayer/water interfaces using the umbrella sampling method is reported. Recently proposed GROMOS96/OPLS compatible models for DME and DMP have been used for the simulation studies. The percolation free energy barrier of one DME and DMP molecule from water to n-heptane phase calculated using the umbrella sampling method turned out to be equal to ∼18.5 kJ/mol and ∼6 kJ/mol, respectively. In the case of the DMPC lipid bilayer, overall free energy barriers of ∼20 kJ/mol and ∼12 kJ/mol were obtained for DME and DMP, respectively. The spontaneous diffusion of DME and DMP in the lipid bilayer has also been investigated using unconstrained molecular dynamics simulations at the water/DMPC interface and inside the lipid bilayer. As expected from the estimated percolation barriers, simulation results show that DME, contrary to DMP, spontaneously diffuse into the aqueous solution from the lipid interior. In addition, simulations with multiple DME or DMP molecules at the interface show spontaneous diffusion within 50 ns inside the DMPC layer only for DMP. © 2012 American Chemical Society.

Two equivalents of the unsymmetrical Schiff base ligand (L(tBu))(-) (4-tert-butyl phenyl(pyrrolato-2-ylmethylene)amine) and MoCl(2)(NtBu)O(dme) (dme = 1,2-dimethoxyethane) gave a single stereoisomer of a mixed imido/oxido Mo(VI) complex 2(tBu). The stereochemistry of 2(tBu) was elucidated using X-ray diffraction, NMR spectroscopy, and DFT calculations. The complex is active in an oxygen atom transfer (OAT) reaction to trimethyl phosphane. The putative intermediate five-coordinate Mo(IV) imido complex coordinates a PMe(3) ligand, giving the six-coordinate imido phosphane Mo(IV) complex 5(tBu). The stereochemistry of 5(tBu) is different from that of 2(tBu) as shown by NMR spectroscopy, DFT calculations, and X-ray diffraction. Single-electron oxidation of 5(tBu) with ferrocenium hexafluorophosphate gave the stable cationic imido phosphane Mo(V) complex [5(tBu)](+) as the PF(6)(-) salt. EPR spectra of [5(tBu)](PF(6)) confirmed the presence of PMe(3) in the coordination sphere. Single-crystal X-ray diffraction analysis of [5(tBu)](PF(6)) revealed that electron transfer occurred under retention of the stereochemical configuration. The rate of OAT, the outcome of the electron transfer reaction, and the stabilities of the imido complexes presented here differ dramatically from those of analogous oxido complexes.

Mesoporous SBA-15 with different Fe2O3 loading were synthesized by an in-situ coating progress for removals of dichlorodiphenyltrichloroethane (DDT) and its derivatives, i.e., 1,1-dichloro-2,2-bis-(p-chlorophenyl)ethane (DDD) and 1,1-dichloro-2,2-bis-(4-chloro -phenyl) ethane (DDE). The results from XRD (X-ray diffractometer), TEM (transmission electron microscopy) indicated that the iron could be well dispersed on SBA-15 within 6 wt.% Fe2O3 loading. Nitrogen adsorption-desorption tests indicated that the synthesized materials were characterized by ordered meso-structure, high surface area and large pore volume. DDTs were removed from aqueous media in 12-hr treatment and high removal efficiency of DDTs was achieved at over 94%. DDTs could be completely degraded at 350 degrees C under the existence of SBA-15 with 4 wt.% Fe2O3 loading. The final degradation products of DDT were dichlorobenzophenone (DCB) and bis-(4-chloro-phenyl) methane (DDM), suggesting a complete dechlorination from trichloromethyl.

s The present work describes the preparation of new chitosan complex with 4-(ethoxycarbonyl) phenyl-1-amino-oxobutanoic acid (ETHA), as a matrix for silver nanoparticles to obtain a nanocomposite film by solution casing method. The characterization of the prepared nanocomposite film was made by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetry (TG) and scanning electron microscopy (SEM). The optical property of nanocomposite film was analyzed by UV–Visible and photo-luminescence (PL) spectroscopy. The nanocomposite film was screen for antibacterial activity with Staphylococcus aureus (gram positive), Pseudomonas aurigionasa (gram negative) and Escherichia coli (gram negative) bacteria by adopting the disk diffusion method. The result of antibacterial study revealed that the prepared nanocomposite film may be a promising candidate for wide range of bio-medical applications.

We propose a new transferable force field to simulate phase equilibrium and interfacial properties of systems involving ethers and glycol ethers. On the basis of the anisotropic united-atom force field, only one new group is introduced: the ether oxygen atom. The optimized Lennard-Jones (LJ) parameters of this atom are identical whatever the molecule simulated (linear ether, branched ether, cyclic ether, aromatic ether, diether, or glycol ether). Accurate predictions are achieved for pure compound saturated properties, critical properties, and surface tensions of the liquid-vapor interface, as well as for pressure-composition binary mixture diagrams. Multifunctional molecules (1,2-dimethoxyethane, 2-methoxyethanol, diethylene glycol) have also been studied using a recently proposed methodology for the calculation of the intramolecular electrostatic energy avoiding the use of additional empirical parameters. This new force field appears transferable for a wide variety of molecules and properties. It is furthermore worth noticing that binary mixtures have been simulated without introducing empirical binary parameters, highlighting also the transferability to mixtures. Hence, this new force field gives future opportunities to simulate complex systems of industrial interest involving molecules with ether functions.

In the National Toxicology Program’s toxicity studies, rats were more sensitive than mice to Bis(2-chloroethoxy)methane (CEM) – induced cardiac toxicity following dermal application to male and female F344/N rats and B6C3F1 mice. Thiodiglycolic acid (TDGA) is a major metabolite of CEM in rats. It has been implicated that chemicals metabolized to TDGA cause cardiac toxicity in humans. Therefore, the toxicokinetics of CEM and TDGA were investigated in male and female F344/N rats and B6C3F1 mice following a single intravenous administration or dermal application of CEM to aid in the interpretation of the toxicity data. Absorption of CEM following dermal application was rapid in both species and genders. Bioavailability following dermal application was low but was higher in rats than in mice with females of both species showing higher bioavailability than males. CEM was rapidly distributed to the heart, thymus, and liver following both routes of administration. Plasma CEM C(max) and AUC(∞) increased proportionally with dose, although at the dermal dose of 400 mg/kg in rats and 600 mg/kg in mice non-linear kinetics were apparent. Following dermal application, dose-normalized plasma CEM C(max) and AUC(∞) was significantly higher in rats than in mice (p-value < 0.0001 for all comparisons except for C(max) in the highest dose groups where p-value = 0.053). In rats, dose-normalized plasma CEM C(max) and AUC(∞) was higher in females than in males: however, the difference was significant only at the lowest dose (p-value = 0.009 for C(max) and 0.056 for AUC(∞)). Similar to rats, female mice also showed higher C(max) and AUC(∞) in females than in male: the difference was significant only for C(max) at the lowest dose (p-value = 0.002). Dose-normalized heart CEM C(max) was higher in rats than in mice and in females than their male counterparts. The liver CEM C(max) was lower compared to that of heart and thymus in both rats and mice following intravenous administration and in rats following dermal application. This is likely due to the rapid metabolism of CEM in the liver as evidenced by the high concentration of TDGA measured in the liver. Dose-normalized plasma and heart TDGA C(max) values were higher in rats compared to mice. In rats, females had higher plasma and heart TDGA C(max) than males; however, there was no gender difference in plasma or heart TDGA C(max) in mice. These findings support the increased sensitivity of rats compared to mice to CEM-induced cardiac toxicity. Data also suggest that, either CEM C(max) or AUC can be used to predict the CEM-induced cardiac toxicity. Although, both plasma and heart TDGA C(max) was consistent with the observed species difference and the gender difference in rats, the gender difference in mice to cardiac toxicity could not be explained based on the TDGA data. This animal study suggests that toxicologically significant concentrations of CEM and TDGA could possibly be achieved in the systemic circulation and/or target tissues in humans as a result of dermal exposure to CEM.

Microporous membranes are an attractive alternative to circumvent the typical drawbacks associated to bead-based chromatography. In particular, the present work intends to evaluate different affinity membranes for antibody capture, to be used as an alternative to Protein A resins. To this aim, two Mimetic Ligands™ A2P and B14, were coupled onto different epoxide and azide group activated membrane supports using different spacer arms and immobilization chemistries. The spacer chemistries investigated were 1,2-diaminoethane (2LP), 3,6-dioxa-1,8-octanedithiol (DES) and [1,2,3] triazole (TRZ). These new mimetic membrane materials were investigated by static and by dynamic binding capacity studies, using pure polyclonal human immunoglobulin G (IgG) solutions as well as a real cell culture supernatant containing monoclonal IgG1. The best results were obtained by combining the new B14 ligand with a TRZ-spacer and an improved Epoxy 2 membrane support material. The new B14-TRZ-Epoxy 2 membrane adsorbent provided binding capacities of approximately 3.1 mg/mL, besides (i) a good selectivity towards IgG, (ii) high IgG recoveries of above 90%, (iii) a high Pluronic-F68 tolerance and (iv) no B14-ligand leakage under harsh cleaning-in-place conditions (0.6 M sodium hydroxide). Furthermore, foreseeable improvements in binding capacity will promote the implementation of membrane adsorbers in antibody manufacturing.

Analysis of volatile organic compounds (VOCs) provides an elegant approach for cancer screening and disease monitoring, whose use is currently limited by a lack of validated cancer-derived metabolites, which may serve as biomarkers. The aim of the experiments presented here was to investigate the release and consumption of VOCs from the non small cell lung cancer cell line NCI-H1666, which was originally derived from a bronchoalveolar carcinoma.Following detachment by trypsinization suspended cells were incubated in a sealed fermenter for 21 hours. 200 ml of headspace from the cell culture were sampled, diluted with dry, highly purified air and preconcentrated by adsorption on three different solid sorbents with increasing adsorption strength. VOC-analysis was performed by thermodesorption-gas chromatography mass spectrometry (TD-GC-MS). In contrast to our previous studies experiments with NCI-H1666 cells only confirmed the consumption of several aldehydes, n-butyl acetate and the ethers methyl tert-butyl ether and ethyl tert-butyl ether, but no unequivocal release of VOCs was observed. Together with our previously published work these data indicate that the consumption of certain VOCs is commonly observed while their release shows cell line-restricted patterns, whose underlying causes are unknown.

Recently, many chemicals released into the environment have been shown to mimic endogenous hormones such as estradiol. It has been demonstrated that these compounds cause several adverse effects on wildlife and humans, such as the feminization of animal species, development of physical abnormalities and birth defects, and reproductive failure. In an effort to model the behaviour of some endocrine-disrupting chemicals (EDCs) and to establish the level of contamination in sewage samples, a quantitative method for the simultaneous determination of nonylphenol, octylphenol and corresponding ethoxylates (1-12), 17α-ethynylestradiol, bisphenol-A, and 17β-estradiol and two of its metabolites have been developed. Identification and quantification were achieved by high performance liquid chromatography-tandem mass spectrometry (LC-ESI-MS/MS). Satisfactory detection limits (between 0.5-6 ng L(-1) in the dissolved phase and 1.4-12.7 ng g(-1) in the particulate phase) and analyte recoveries (between 60% and 108%) were achieved for target compounds. The optimised method was applied to the determination of EDCs in liquid sewage samples collected from a wastewater treatment plant (WWTP) in Las Palmas de Gran Canaria (Spain). Concentrations of EDCs ranged from10 ng L(-1) to nearly 1200 ng L(-1) in the dissolved phase, and from 0.005 μg g(-1) to 2.8 μg g(-1) in the suspended particulate matter.

A range of methyl and ethyl ethers of aliphatic alcohols have been synthesized cleanly in high yield by reacting the corresponding alcohol with dimethyl carbonate or diethyl carbonate over the solid acid catalyst, γ-alumina. The reaction could be conducted at ambient pressure without the need for the large excess of dialkyl carbonate as previously reported in the literature. If the reaction was conducted at high pressure, the conversion of the starting alcohol was greatly reduced. However, high pressure CO2 can be used as the solvent without significant reduction in yield. This has implications for tandem reactions.

Analysis of trace amino acids (AA) in physiological fluids has received more attention, because the analysis of these compounds could provide fundamental and important information for medical, biological, and clinical researches. More accurate method for the determination of those compounds is highly desirable and valuable. In the present study, we developed a selective and sensitive method for trace AA determination in biological samples using 2-[2-(7H-dibenzo [a,g]carbazol-7-yl)-ethoxy] ethyl chloroformate (DBCEC) as labeling reagent by HPLC-FLD-MS/MS. Response surface methodology (RSM) was first employed to optimize the derivatization reaction between DBCEC and AA. Compared with traditional single-factor design, RSM was capable of lessening laborious, time and reagents consumption. The complete derivatization can be achieved within 6.3 min at room temperature. In conjunction with a gradient elution, a baseline resolution of 20 AA containing acidic, neutral, and basic AA was achieved on a reversed-phase Hypersil BDS C(18) column. This method showed excellent reproducibility and correlation coefficient, and offered the exciting detection limits of 0.19-1.17 fmol/μL. The developed method was successfully applied to determinate AA in human serum. The sensitive and prognostic index of serum AA for liver diseases has also been discussed.