Comparative embryotoxicity of a pentabrominated diphenyl ether mixture to common terns (Sterna hirundo) and American kestrels (Falco sparverius)

USGS Publications Warehouse

Rattner, Barnett A.; Lazarus, Rebecca S.; Heinz, Gary H.; Karouna-Reiner, Natalie K.; Schultz, Sandra L.; Hale, Robert C.

2013-01-01

Concentrations of polybrominated diphenyl ethers (PBDEs) in Forster’s tern (Sterna forsteri) eggs from San Francisco Bay have been reported to range up to 63 μg g−1 lipid weight. This value exceeds the lowest-observed-adverse-effect level (1.8 μg g−1 egg wet weight; ∼32 μg−1 lipid weight) reported in an embryotoxicity study with American kestrels (Falco sparverius). As a surrogate for Forster’s terns, common tern (Sterna hirundo) eggs were treated by air cell injection with corn oil vehicle (control) or a commercial penta-BDE formulation (DE-71) at nominal concentrations of 0.2, 2, and 20 μg g−1 egg. As a positive control, kestrel eggs received vehicle or 20 μg DE-71 g−1 egg. In terns, there were no effects of DE-71 on embryonic survival, and pipping or hatching success; however, treated eggs hatched later (0.44 d) than controls. Organ weights, organ-to-body weight ratios, and bone lengths did not differ, and histopathological observations were unremarkable. Several measures of hepatic oxidative stress in hatchling terns were not affected by DE-71, although there was some evidence of oxidative DNA damage (8-hydroxy-deoxyguanosine; 8-OH-dG). Although DE-71 did not impair pipping and hatching of kestrels, it did result in a delay in hatch, shorter humerus length, and reduced total thyroid weight. Concentrations of oxidized glutathione, reduced glutathione, thiobarbituric acid reactive substances, and 8-OH-dG in liver were greater in DE-71-treated kestrels compared to controls. Our findings suggest common tern embryos, and perhaps other tern species, are less sensitive to PBDEs than kestrel embryos.

Thyroid hormone disruption and cognitive impairment in rats exposed to PBDE during postnatal development.

PubMed

de-Miranda, Andressa S; Kuriyama, Sergio N; da-Silva, Camille S; do-Nascimento, Monicke S C; Parente, Thiago E M; Paumgartten, Francisco J R

2016-08-01

Polybrominated diphenyl ether flame-retardants (PBDEs) are thyroid-disrupting environmental chemicals. We investigated the effects of postnatal exposure to DE-71 (a mixture of tetra- and penta-brominated congeners), n-propylthiouracil (PTU) and thyroxine (T4) replacement on open-field (OF) and radial maze (RAM) tests. Wistar rats (5 males/5 females per litter, 32 litters) were treated orally (PND 5-22) with PTU (4mg/kg bw/d), DE-71 (30mg/kg bw/d), with and without co-administration of T4 (15μg/kg bw/d, sc). PTU depressed T4 serum levels and body weight gain and enlarged thyroid gland. Although decreasing T4 levels, DE-71 did not change thyroid and body weights. PTU-treated rats showed hyperactivity (PND 42 and 70), and working and reference memory learning deficits (RAM, PND 100). Although not altering motor activity and working memory, DE-71 caused a reference memory deficit (females only). T4 co-administration averted hypothyroxinemia and long-term cognitive deficits caused by PTU and DE-71. Copyright © 2016 Elsevier Inc. All rights reserved.

Developmental exposure to a commercial PBDE mixture, DE-71: neurobehavioral, hormonal, and reproductive effects.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kodavanti, Prasada; Coburn, Cary; Moser, Virginia

2010-06-01

Developmental effects of polybrominated diphenyl ethers (PBDEs) have been suspected due to their structural similarities to polychlorinated biphenyls (PCBs). This study evaluated neurobehavioral, hormonal, and reproductive effects in rat offspring perinatally exposed to a widely used pentabrominated commercial mixture, DE-71. Pregnant Long-Evans rats were exposed to 0, 1.7, 10.2, or 30.6 mg/kg/day DE-71 in corn oil by oral gavage from gestational day 6 to weaning. DE-71 did not alter maternal or male offspring body weights. However, female offspring were smaller compared with controls from postnatal days (PNDs) 35-60. Although several neurobehavioral endpoints were assessed, the only statistically significant behavioral findingmore » was a dose-by-age interaction in the number of rears in an open-field test. Developmental exposure to DE-71 caused severe hypothyroxinemia in the dams and early postnatal offspring. DE-71 also affected anogenital distance and preputial separation in male pups. Body weight gain over time, reproductive tissue weights, and serum testosterone concentrations at PND 60 were not altered. Mammary gland development of female offspring was significantly affected at PND 21. Congener-specific analysis of PBDEs indicated accumulation in all tissues examined. Highest PBDE concentrations were found in fat including milk, whereas blood had the lowest concentrations on a wet weight basis. PBDE concentrations were comparable among various brain regions. Thus, perinatal exposure to DE-71 leads to accumulation of PBDE congeners in various tissues crossing blood-placenta and blood-brain barriers, causing subtle changes in some parameters of neurobehavior and dramatic changes in circulating thyroid hormone levels, as well as changes in both male and female reproductive endpoints. Some of these effects are similar to those seen with PCBs, and the persistence of these changes requires further investigation.« less

CONGENER PROFILES OF POLYBROMINATED BIPHENYLS, -DIBENZO-P-DIOXINS AND -DIBENZOFURANS AS IMPURITIES IN TECHNICAL PREPARATION OF POLYBROMIANTED DIPHENYL ETHERS.

EPA Science Inventory

Polybrominated diphenyl ethers (PBDEs) are flame retardants used in textiles, and electronic equipment to prevent these products from burning. PBDEs have been marketed as penta- (DE-71), octa- (DE-79), and deca-brominated (DE-83) preparations. Commercial PBDE preparations were an...

Polybrominated Diphenyl Ethers Alter Hepatic Phosphoenolpyruvate Carboxykinase Enzyme Kinetics in Male Wistar Rats: Implications for Lipid and Glucose Metabolism

EPA Science Inventory

Polybrominated diphenyl ethers (PBDE) are a family of lipophilic brominated flame-retardants consisting of 209 possible congeners. Three PBDE commercially-produced mixtures are decabrominated diphenyl ether (e.g. deca-BDE or DE-83R); octabrominated diphenyl ether (e.g. octa-BDE o...

Endocrine disruption and reproduction impairment in zebrafish after long-term exposure to DE-71.

PubMed

Yu, Liqin; Liu, Chunsheng; Chen, Qi; Zhou, Bingsheng

2014-06-01

The objective of the present study was to investigate the impact of polybrominated diphenyl ethers (PBDEs) on fish reproduction over 2 generations. Zebrafish (Danio rerio) embryos (F0) were exposed to low concentrations (3 µg/L, 10 µg/L, and 30 µg/L) of the PBDE mixture DE-71 until they were sexually mature, and steroid hormone production, expression of genes involved in steroidogenesis, gonadal development, and gamete characteristics were examined. Exposure of female zebrafish to DE-71 resulted in lower estradiol production and downregulation of cytochrome P450 aromatase mRNA. In males, exposure to DE-71 resulted in greater testosterone production and greater cytochrome P450 c17 α-hydroxylase,17,20-lase mRNA expression. Moreover, hepatic vitellogenin mRNA and estrogenic receptor β gene transcription were downregulated in females and males. Expression of the follicle-stimulating hormone β gene in the pituitary was upregulated, and the expression of luteinizing hormone β was downregulated in both sexes. Histological examination showed inhibition of oocyte maturation in females and retarded spermiation in males. The average number of eggs (F1) produced was also reduced. Additionally, exposure of F0 embryos to DE-71 did not result in developmental toxicity, whereas delayed hatching, reduced survival, and decreased growth were observed in the F1 embryos derived from parent fish exposed to DE-71. Therefore, long-term exposure to low concentrations of PBDEs in zebrafish could cause reproductive impairment, suggesting that PBDEs might have significant adverse effects on fish population in the highly PBDEs-contaminated aquatic environment. © 2014 SETAC.

Polybrominated Diphenyl Ether (DE-71)Interferes with Thyroid Hormone Action Independent Of Effects On Circulating Levels of Thyroid Hormone in Male Rats

EPA Science Inventory

Polybrominated diphenyl ethers (PBDEs) are routinely found in human tissues including cord blood and breast milk. PBDEs may interfere with thyroid hormone (TH) during development, which could produce neurobehavioral deficits. An assumption in experimental and epidemiological stud...

Effects of Chronic Exposure to an Environmentally Relevant Mixture of Brominated Flame Retardants on the Reproductive and Thyroid System in Adult Male Rats

PubMed Central

Ernest, Sheila R.; Wade, Michael G.; Lalancette, Claudia; Ma, Yi-Qian; Berger, Robert G.; Robaire, Bernard; Hales, Barbara F.

2012-01-01

Brominated flame retardants (BFRs) are incorporated into a wide variety of consumer products, are readily released into home and work environments, and are present in house dust. Studies using animal models have revealed that exposure to polybrominated diphenyl ethers (PBDEs) may impair adult male reproductive function and thyroid hormone physiology. Such studies have generally characterized the outcome of acute or chronic exposure to a single BFR technical mixture or congener but not the impact of environmentally relevant BFR mixtures. We tested whether exposure to the BFRs found in house dust would have an adverse impact on the adult male rat reproductive system and thyroid function. Adult male Sprague Dawley rats were exposed to a complex BFR mixture composed of three commercial brominated diphenyl ethers (52.1% DE-71, 0.4% DE-79, and 44.2% decaBDE-209) and hexabromocyclododecane (3.3%), formulated to mimic the relative congener levels in house dust. BFRs were delivered in the diet at target doses of 0, 0.02, 0.2, 2, or 20 mg/kg/day for 70 days. Compared with controls, males exposed to the highest dose of BFRs displayed a significant increase in the weights of the kidneys and liver, which was accompanied by induction of CYP1A and CYP2B P450 hepatic drug–metabolizing enzymes. BFR exposure did not affect reproductive organ weights, serum testosterone levels, testicular function, or sperm DNA integrity. The highest dose caused thyroid toxicity as indicated by decreased serum thyroxine (T4) and hypertrophy of the thyroid gland epithelium. At lower doses, the thickness of the thyroid gland epithelium was reduced, but no changes in hormone levels (T4 and thyroid-stimulating hormone) were observed. Thus, exposure to BFRs affected liver and thyroid physiology but not male reproductive parameters. PMID:22387749

Toxicity of polybrominated diphenyl ethers (de-71) in chicken (Gallus gallus), mallard (Anas platyrhynchos), and American kestrel (Falco sparverius) embryos and hatchlings

USGS Publications Warehouse

McKernan, M.A.; Rattner, B.A.; Hale, R.C.; Ottinger, M.A.

2009-01-01

Embryonic survival, pipping and hatching success, and sublethal biochemical, endocrine, and histological endpoints were examined in hatchling chickens (Gallus gallus), mallards (Anas platyrhynchos), and American kestrels (Falco sparverius) following air cell administration of a pentabrominated diphenyl ether (penta-BDE; DE-71) mixture (0.01-20 mu g/g egg) or polychlorinated biphenyl (PCB) congener 126 (3,3', 4,4', 5-pentachlorobiphenyl; 0.002 mu g/g egg). The penta-BDE decreased pipping and hatching success at concentrations of 10 and 20 mu g/g egg in kestrels but had no effect on survival endpoints in chickens or mallards. Sublethal effects in hatchling chickens included ethoxyresorufin-O-dealkylase (EROD) induction and histological changes in the bursa, but these responses were not observed in other species. Polychlorinated biphenyl congener 126 (positive control) reduced survival endpoints in chicken and kestrel embryos and caused sublethal effects (EROD induction, reduced bursal mass and follicle size) in chickens. Mallards were clearly less sensitive than the other species to administered penta-BDE and PCB 126. In a second experiment, the absorption of penta-BDE (11.1 mu g/g egg, air cell administered during early development) into the contents of chicken and kestrel eggs was determined at various intervals (24 h postinjection, midincubation, and pipping). By pipping, 29% of the penta-BDE administered dose was present in the egg contents in chickens, and 18% of the administered dose was present in kestrel egg contents. Based on uptake in kestrels, the lowest-observed-effect level on pipping and hatching success may be as low as 1.8 mu g total penta-BDE/g egg, which approaches concentrations detected in eggs of free-ranging birds. Because some penta-BDE congeners are still increasing in the environment, the toxic effects observed in the present study are cause for concern in wildlife.

CHANGES IN PROTEOMIC PROFILES OF CEREBELLUM FOLLOWING DEVELOPMENTAL EXPOSURE TO AROCLOR 1254 OR DE-71.

EPA Science Inventory

Chronic low level exposure to polychlorinated biphenyls (PCBs) has been shown to adversely affect human health, including learning and memory. Polybromiated diphenyl ethers (PBDEs) are structurally similar to PCBs and have been shown to have neurotoxic effects in vitro and in viv...

NEUROBEHAVIORAL ASSESSMENT USING A FUNCTIONAL OBSERVATIONAL BATTERY AND MOTOR ACTIVITY IN RATS PERINATALLY EXPOSED TO DE-71.

EPA Science Inventory

Polybrominated Diphenyl ethers (PBDEs) have been widely used as flame retardants in a variety of commercial products. Their persistence in the environment and detection in populations throughout the world has raised concern about their toxic effects. Developmental Neurotoxic ef...

Partitioning and diffusion of PBDEs through an HDPE geomembrane.

PubMed

Rowe, R Kerry; Saheli, Pooneh T; Rutter, Allison

2016-09-01

Polybrominated diphenyl ether (PBDE) has been measured in MSW landfill leachate and its migration through a modern landfill liner has not been investigated previously. To assure environmental protection, it is important to evaluate the efficacy of landfill liners for controlling the release of PBDE to the environment to a negligible level. The partitioning and diffusion of a commercial mixture of PBDEs (DE-71: predominantly containing six congeners) with respect to a high-density polyethylene (HDPE) geomembrane is examined. The results show that the partitioning coefficients of the six congeners in this mixture range from 700,000 to 7,500,000 and the diffusion coefficients range from 1.3 to 6.0×10(-15)m(2)/s depending on the congener. This combination of very high partitioning coefficients and very low diffusion coefficients suggest that a well constructed HDPE geomembrane liner will be an extremely effective barrier for PBDEs with respect to diffusion from a municipal solid waste landfill, as illustrated by an example. The results for pure diffusion scenario showed that the congeners investigated meet the guidelines by at least a factor of three for an effective geomembrane liner where diffusion is the controlling transport mechanism. Copyright © 2016 Elsevier Ltd. All rights reserved.

IN VIVO AND IN VITRO ANTI-ANDROGENIC EFFECTS OF DE-71

EPA Science Inventory

Recently, we showed that the PBDE mixture, DE-71, delayed preputial separation (PPS) and suppressed the growth of androgen-dependent tissues in the Wistar rat following a peri-pubertal exposure. These effects occurred concurrently with hypothyroidism and suggested that in additi...

2,2",4,4"-TETRABROMODIPHENYL (PBDE 47) ALTERS THYROID FUNCTION IN THE RAT.

EPA Science Inventory

Two commercial PBDE mixtures, DE-71 and DE-79, cause dose-dependent depletion of serum T4 via induction of UGTs and increased CYP1A1 activity. This work characterized the effect of a major congener, PBDE-47, in DE-71 for effects on hepatic enzymes and thyroid hormones. Female 27...

Successful Initial Development of Styrene Substitutes and Suppressants for Vinyl Ester Resin Formulations

DTIC Science & Technology

2003-08-01

into a separatory funnel. Distilled water was added to remove the acid from the ether phase. The layers were allowed to separate, and the water layer...The reaction mixtures were removed from the heat 2 hr after the last acrylic acid aliquot was added. The acrylated oils were purified via ether... remove inhibitor and any unreacted acid , the reaction mixture was ether extracted (25). The mixture was dissolved in diethyl ether and poured into a

The influence of water mixtures on the dermal absorption of glycol ethers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Traynor, Matthew J.; Wilkinson, Simon C.; Williams, Faith M.

2007-01-15

Glycol ethers are solvents widely used alone and as mixtures in industrial and household products. Some glycol ethers have been shown to have a range of toxic effects in humans following absorption and metabolism to their aldehyde and acid metabolites. This study assessed the influence of water mixtures on the dermal absorption of butoxyethanol and ethoxyethanol in vitro through human skin. Butoxyethanol penetrated human skin up to sixfold more rapidly from aqueous solution (50%, 450 mg/ml) than from the neat solvent. Similarly penetration of ethoxyethanol was increased threefold in the presence of water (50%, 697 mg/ml). There was a correspondingmore » increase in apparent permeability coefficient as the glycol ether concentration in water decreased. The maximum penetration rate of water also increased in the presence of both glycol ethers. Absorption through a synthetic membrane obeyed Fick's Law and absorption through rat skin showed a similar profile to human skin but with a lesser effect. The mechanisms for this phenomenon involves disruption of the stratum corneum lipid bilayer by desiccation by neat glycol ether micelles, hydration with water mixtures and the physicochemical properties of the glycol ether-water mixtures. Full elucidation of the profile of absorption of glycol ethers from mixtures is required for risk assessment of dermal exposure. This work supports the view that risk assessments for dermal contact scenarios should ideally be based on absorption data obtained for the relevant formulation or mixture and exposure scenario and that absorption derived from permeability coefficients may be inappropriate for water-miscible solvents.« less

Synergic effects in the extraction of paracetamol from aqueous NaCl solution by the binary mixtures of diethyl ether and low molecular weight primary alcohols

NASA Astrophysics Data System (ADS)

Nikolić, G. M.; Živković, J. V.; Atanasković, D. S.; Nikolić, M. G.

2013-12-01

Liquid-liquid extraction of paracetamol from aqueous NaCl solutions was performed with diethyl ether, 1-propanol, 1-butanol, isobutanol, 1-pentanol, and binary mixtures diethyl ether/1-propanol, diethyl ether/1-butanol, and diethyl ether/isobutanol. Among the pure solvents investigated in this study best extraction efficacy was obtained with 1-butanol. Synergic effects in the extraction with binary mixtures was investigated and compared with some other systems used for the extraction of poorly extractable compounds. Results obtained in this study may be of both fundamental and practical importance.

Altered cardiovascular reactivity and osmoregulation during hyperosmotic stress in adult rats developmentally exposed to polybrominated diphenyl ethers (PBDEs)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shah, Ashini; Coburn, Cary G.; Watson-Siriboe, Abena

2011-10-15

Polybrominated diphenyl ethers (PBDEs) and the structurally similar chemicals polychlorinated biphenyls (PCBs) disrupt the function of multiple endocrine systems. PCBs and PBDEs disrupt the secretion of vasopressin (VP) from the hypothalamus during osmotic activation. Since the peripheral and central vasopressinergic axes are critical for osmotic and cardiovascular regulation, we examined whether perinatal PBDE exposure could impact these functions during physiological activation. Rats were perinatally dosed with a commercial PBDE mixture, DE-71. Dams were given 0 (corn oil control), 1.7 (low dose) or 30.6 mg/kg/day (high dose) in corn oil from gestational day (GD) 6 through postnatal day (PND) 21 bymore » oral gavage. In the male offspring exposed to high dose PBDE plasma thyroxine and triiodothyronine levels were reduced at PND 21 and recovered to control levels by PND 60 when thyroid stimulating hormone levels were elevated. At 14-18 months of age, cardiovascular responses were measured in four groups of rats: Normal (Oil, normosmotic condition), Hyper (Oil, hyperosmotic stress), Hyper PBDE low (1.7 mg/kg/day DE-71 perinatally, hyperosmotic stress), and Hyper PBDE high (30.6 mg/kg/day DE-71 perinatally, hyperosmotic stress). Systolic blood pressure (BP), diastolic BP, and heart rate (HR) were determined using tail cuff sphygmomanometry and normalized to pretreatment values (baseline) measured under basal conditions. Hyperosmotic treatment yielded significant changes in systolic BP in PBDE exposed rats only. Hyper PBDE low and high dose rats showed 36.1 and 64.7% greater systolic BP responses at 3 h post hyperosmotic injection relative to pretreatment baseline, respectively. No treatment effects were measured for diastolic BP and HR. Hyper and Hyper PBDE rats showed increased mean plasma osmolality values by 45 min after injection relative to normosmotic controls. In contrast to Hyper rats, Hyper PBDE (high) rats showed a further increase in mean plasma osmolality at 3 h (358.3 {+-} 12.4 mOsm/L) relative to 45 min post hyperosmotic injection (325.1 {+-} 11.4 mOsm/L). Impaired osmoregulation in PBDE-treated animals could not be attributed to decreased levels of plasma vasopressin. Our findings suggest that developmental exposure to PBDEs may disrupt cardiovascular reactivity and osmoregulatory responses to physiological activation in late adulthood. - Highlights: > We examined whether PBDE exposure could impact osmotic and cardiovascular regulation. > Hyperosmotic treatment yielded significant changes in systolic BP in PBDE exposed rats only. > PBDEs may disrupt cardiovascular and osmoregulatory responses to physiological activation.« less

Isolation of bacterial strains able to degrade biphenyl, diphenyl ether and the heat transfer fluid used in thermo-solar plants.

PubMed

Blanco-Moreno, Rafael; Sáez, Lara P; Luque-Almagro, Víctor M; Roldán, M Dolores; Moreno-Vivián, Conrado

2017-03-25

Thermo-solar plants use eutectic mixtures of diphenyl ether (DE) and biphenyl (BP) as heat transfer fluid (HTF). Potential losses of HTF may contaminate soils and bioremediation is an attractive tool for its treatment. DE- or BP-degrading bacteria are known, but up to now bacteria able to degrade HTF mixture have not been described. Here, five bacterial strains which are able to grow with HTF or its separate components DE and BP as sole carbon sources have been isolated, either from soils exposed to HTF or from rhizospheric soils of plants growing near a thermo-solar plant. The organisms were identified by 16S rRNA gene sequencing as Achromobacter piechaudii strain BioC1, Pseudomonas plecoglossicida strain 6.1, Pseudomonas aeruginosa strains HBD1 and HBD3, and Pseudomonas oleovorans strain HBD2. Activity of 2,3-dihydroxybiphenyl dioxygenase (BphC), a key enzyme of the biphenyl upper degradation pathway, was detected in all isolates. Pseudomonas strains almost completely degraded 2000ppm HTF after 5-day culture, and even tolerated and grew in the presence of 150,000ppm HTF, being suitable candidates for in situ soil bioremediation. Degradation of both components of HTF is of particular interest since in the DE-degrader Sphingomonas sp. SS3, growth on DE or benzoate was strongly inhibited by addition of BP. Copyright © 2016 Elsevier B.V. All rights reserved.

Global Gridded Emission Inventories of Pentabrominated Diphenyl Ether (PeBDE)

NASA Astrophysics Data System (ADS)

Li, Yi-Fan; Tian, Chongguo; Yang, Meng; Jia, Hongliang; Ma, Jianmin; Li, Dacheng

2010-05-01

Polybrominated diphenyl ethers (PBDEs) are flame retardants widely used in many everyday products such as cars, furniture, textiles, and other electronic equipment. The commercial PBDEs have three major technical mixtures: penta-(PeBDE), octa-(OBDE) and decabromodiphenyl ethers (DeBDE). PeBDE is a mixture of several BDE congeners, such as BDE-47, -99, and -100, and has been included as a new member of persistent organic pollutants (POPs) under the 2009 Stockholm Convention. In order to produce gridded emission inventories of PeBDE on a global scale, information of production, consumption, emission, and physiochemical properties of PeBDE have been searched for published papers, government reports, and internet publications. A methodology to estimate the emissions of PeBDE has been developed and global gridded emission inventories of 2 major congener in PeBDE mixture, BDE-47 and -99, on a 1 degree by 1degree latitude/longitude resolution for 2005 have been compiled. Using these emission inventories as input data, the Canadian Model for Environmental Transport of Organochlorine Pesticides (CanMETOP) model was used to simulate the transport of these chemicals and their concentrations in air were calculated for the year of 2005. The modeled air concentration of BDE-47 and -99 were compared with the monitoring air concentrations of these two congeners in the same year obtained from renowned international/national monitoring programs, such as Global Atmospheric Passive Sampling (GAPS), the Integrated Atmospheric Deposition Network (IADN), and the Chinese POPs Soil and Air Monitoring Program (SAMP), and significant correlations between the modeled results and the monitoring data were found, indicating the high quality of the produced emission inventories of BDE-47 and -99. Keywords: Pentabrominated Diphenyl Ether (PeBDE), Emission Inventories, Global, Model

Editor’s Highlight: Comparative Toxicity of Organophosphate Flame Retardants and Polybrominated Diphenyl Ethers to Caenorhabditis elegans

PubMed Central

Behl, Mamta; Rice, Julie R.; Smith, Marjo V.; Co, Caroll A.; Bridge, Matthew F.; Hsieh, Jui-Hua; Freedman, Jonathan H.; Boyd, Windy A.

2016-01-01

With the phasing-out of the polybrominated diphenyl ether (PBDE) flame retardants due to concerns regarding their potential developmental toxicity, the use of replacement compounds such as organophosphate flame retardants (OPFRs) has increased. Limited toxicity data are currently available to estimate the potential adverse health effects of the OPFRs. The toxicological effects of 4 brominated flame retardants, including 3 PBDEs and 3,3',5,5'-tetrabromobisphenol A, were compared with 6 aromatic OPFRs and 2 aliphatic OPFRs. The effects of these chemicals were determined using 3 biological endpoints in the nematode Caenorhabditis elegans (feeding, larval development, and reproduction). Because C. elegans development was previously reported to be sensitive to mitochondrial function, results were compared with those from an in vitro mitochondrial membrane permeabilization (MMP) assay. Overall 11 of the 12 flame retardants were active in 1 or more C. elegans biological endpoints, with only tris(2-chloroethyl) phosphate inactive across all endpoints including the in vitro MMP assay. For 2 of the C. elegans endpoints, at least 1 OPFR had similar toxicity to the PBDEs: triphenyl phosphate (TPHP) inhibited larval development at levels comparable to the 3 PBDEs; whereas TPHP and isopropylated phenol phosphate (IPP) affected C. elegans reproduction at levels similar to the PBDE commercial mixture, DE-71. The PBDEs reduced C. elegans feeding at lower concentrations than any OPFR. In addition, 9 of the 11 chemicals that inhibited C. elegans larval development also caused significant mitochondrial toxicity. These results suggest that some of the replacement aromatic OPFRs may have levels of toxicity comparable to PBDEs. PMID:27566445

Molecular Engineering of Liquid Crystalline Polymers by Living Polymerization. 8. Influence of Molecular Weight on the Phase Behavior pf Poly(Omega-((4-cyano-4’Biphenyl)oxy)alkyl Vinyl Ether)s with Ethyl, Propyl and Butyl Alkyl Groups

DTIC Science & Technology

1990-10-16

methanol (15 ml). The mixture was refluxed for 12 hr. After cooling and filtration (to remove the catalyst ) the solvent was distilled in a rotavapor and...was controlled by the monomer/initiator ([M]/[I]0 ) ratio. After quenching the polymerization with ammoniacal methanol , the reaction mixture was...The Phase Behavior of Poly(co-[(4-cyano-4’- biphenyl)oxy] alkyl Vinyl Ether]s with Ethyl, Propyl and Butyl Alkyl Groups Acc,--.o ,; ., x .... V

Change in the Gibbs energy of 18-crown-6 ether transfer from methanol to methanol-acetonitrile mixtures at 298 K

NASA Astrophysics Data System (ADS)

Kuz'mina, I. A.; Usacheva, T. R.; Kuz'mina, K. I.; Volkova, M. A.; Sharnin, V. A.

2015-01-01

The Gibbs energies of the transfer of 18-crown-6 ether from methanol to its mixtures with acetonitrile (χAN = 0.0-1.0 mole fraction) are determined by means of interphase distribution at 298 K. The effect the solvent composition has on the thermodynamic characteristics of the solvation of 18-crown-6 ether is analyzed. An increase in the content of acetonitrile in the mixed solvent enhances the solvation of crown ether due to changes in the energy of the solution. Resolvation of the macrocycle is assumed to be complete at acetonitrile concentrations higher than 0.6 mole fraction.

40 CFR 799.5000 - Testing consent orders for substances and mixtures with Chemical Abstract Service Registry Numbers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Environmental Releases Report November 18, 1994. 112-35-6 Triethylene glycol monomethyl ether Health effects... Health effects November 23, 1993. 994-05-8 Tertiary-amyl methyl ether Health effects March 21, 1995. 1634-04-4 Methyl tert-butyl ether Health effects March 31, 1988. 2461-18-9 Lauryl glycidyl ether 1 Health...

"Dry-column" chromatography of plant pigments

NASA Technical Reports Server (NTRS)

Woeller, F. H.; Lehwalt, M. F.; Oyama, V. I.

1973-01-01

Separation of plant pigments which can be accomplished on thin-layer silica plates with mixture of petroleum ether, halocarbon, acetone, and polar solvent can be readily translated into dry-column technique that yields reproducible chromatograms after elution in fashion of liquid chromatography with fluorimeter as detector. Best solvent system was found to be mixture of petroleum ether, dichloromethane, acetone, and ethyl acetate.

Effect of substrate interaction on the degradation of methyl tert-butyl ether, benzene, toluene, ethylbenzene, and xylene by Rhodococcus sp.

PubMed

Lee, Eun-Hee; Cho, Kyung-Suk

2009-08-15

It was examined the substrate interactions of benzene (B), tolulene (T), ethylbenzene (E), xylene (X), and methyl tert-butyl ether (M) in binary, ternary, quaternary, and quinary mixtures by Rhodococcus sp. EH831 that could aerobically degrade all of five single components. The specific degradation rates (SDRs) of B, T, E, X, and M were 234, 913, 131, 184 and 139 micromol g-dry cell weight (DCW)(-1)h(-1), respectively. In binary, ternary, quaternary, and quinary mixtures of them, ethylbenzene was the strongest inhibitor for the other substrates, and methyl tert-butyl ether was the weakest inhibitor. Interestingly, no degradation of benzene and methyl tert-butyl ether was found in the coexistence of ethylbenzene. The degradation of benzene followed only after toluene became exhausted when both was present. Ethylbenzene was least inhibited by methyl tert-butyl ether and most inhibited by toluene.

Dielectric properties of binary mixtures of ethylene glycol monophenyl ether and methanol

NASA Astrophysics Data System (ADS)

Vaghela, K. C.; Vankar, H. P.; Trivedi, C. M.; Rana, V. A.

2017-05-01

Static permittivity (ɛ0) and permittivity at optical frequency (ɛ∞) of ethylene glycol monophenyl ether (EGMPE), methanol (MeOH) and their binary mixtures of varying concentrations have been measured at room temperature (T=299.15 K). The investigation showed a systematic change in permittivity with change in concentration of MeOH in binary mixture system. Measured data have been used to calculate the various dielectric parameters such as E E excess static permittivity (ɛ0E), excess permittivity at optical frequency (ɛ∞E) and Bruggeman factor (fB). Determined parameters provided some information about the molecular interaction among the molecular species of the binary mixtures.

Two-carbon homologation of aldehydes and ketones to α,β-unsaturated aldehydes.

PubMed

Petroski, Richard J; Vermillion, Karl; Cossé, Allard A

2011-06-17

Phosphonate reagents were developed for the two-carbon homologation of aldehydes or ketones to unbranched- or methyl-branched α,β-unsaturated aldehydes. The phosphonate reagents, diethyl methylformyl-2-phosphonate dimethylhydrazone and diethyl ethylformyl-2-phosphonate dimethylhydrazone, contained a protected aldehyde group instead of the usual ester group. A homologation cycle entailed condensation of the reagent with the starting aldehyde, followed by removal of the dimethylhydrazone protective group with a biphasic mixture of 1 M HCl and petroleum ether. This robust two-step process worked with a variety of aldehydes and ketones. Overall isolated yields of unsaturated aldehyde products ranged from 71% to 86% after the condensation and deprotection steps.

Lower critical solution temperature (LCST) phase separation of glycol ethers for forward osmotic control.

PubMed

Nakayama, Daichi; Mok, Yeongbong; Noh, Minwoo; Park, Jeongseon; Kang, Sunyoung; Lee, Yan

2014-03-21

Lower critical solution temperature (LCST) phase transition of glycol ether (GE)-water mixtures induces an abrupt change in osmotic pressure driven by a mild temperature change. The temperature-controlled osmotic change was applied for the forward osmosis (FO) desalination. Among three GEs evaluated, di(ethylene glycol) n-hexyl ether (DEH) was selected as a potential FO draw solute. A DEH-water mixture with a high osmotic pressure could draw fresh water from a high-salt feed solution such as seawater through a semipermeable membrane at around 10 °C. The water-drawn DEH-water mixture was phase-separated into a water-rich phase and a DEH-rich phase at around 30 °C. The water-rich phase with a much reduced osmotic pressure released water into a low-salt solution, and the DEH-rich phase was recovered into the initial DEH-water mixture. The phase separation behaviour, the residual GE concentration in the water-rich phase, the osmotic pressure of the DEH-water mixture, and the osmotic flux between the DEH-water mixture and salt solutions were carefully analysed for FO desalination. The liquid-liquid phase separation of the GE-water mixture driven by the mild temperature change between 10 °C and 30 °C is very attractive for the development of an ideal draw solute for future practical FO desalination.

Polybrominated diphenyl ethers (PBDEs) in soil and outdoor dust from a multi-functional area of Shanghai: levels, compositional profiles and interrelationships.

PubMed

Wu, Ming-Hong; Pei, Jing-Cheng; Zheng, Ming; Tang, Liang; Bao, Yang-Yang; Xu, Ben-Tuo; Sun, Rui; Sun, Yan-Feng; Xu, Gang; Lei, Jian-Qiu

2015-01-01

In this study, 14 polybrominated diphenyl ethers (PBDEs) congeners were investigated in soil and outdoor dust taken from Jiading District, Shanghai City. The concentrations of Σ13PBDEs (BDE-17, BDE-28, BDE-47, BDE-66, BDE-71, BDE-85, BDE-99, BDE-100, BDE-138, BDE-153, BDE-154, BDE-183 and BDE-190) and BDE-209 ranged from 0.37 to 32.9ngg(-1) and 4.31 to 141.8ngg(-1) dry weight (dw) in soil. Concentrations in outdoor dust ranged from 1.03 to 112.5ngg(-1) and 6.71 to 342.1ngg(-1) (dw) for Σ13PBDEs and BDE-209. BDE-209 was the predominant congener both in soil and outdoor dust, but the BDE-209 contribution was much lower in dust compared with that in soil. A significant correlation between PBDEs congeners and specific land use type was observed, and principal component analysis (PCA) revealed that the major source of PBDE in samples was associated with prevalent use of technical Deca-BDE, which also suggested the contributions from Penta-BDE and Octa-BDE mixtures. Canonical correlation analysis suggested the two sets of PBDEs data (soil and outdoor dust) were uncorrelated, and Spearman correlation coefficient matrix implied that the degradation pathways of PBDEs were different between soil and outdoor dust. Copyright © 2014 Elsevier Ltd. All rights reserved.

40 CFR 401.15 - Toxic pollutants.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (technical mixture and metabolites) 14. Chlorinated benzenes (other than di-chlorobenzenes) 15. Chlorinated... ethers (chloroethyl and mixed ethers) 17. Chlorinated naphthalene 18. Chlorinated phenols (other than those listed elsewhere; includes trichlorophenols and chlorinated cresols) 19. Chloroform 20. 2...

Acute exposure to PBDEs at an environmentally realistic concentration causes abrupt changes in the gut microbiota and host health of zebrafish.

PubMed

Chen, Lianguo; Hu, Chenyan; Lok-Shun Lai, Nelson; Zhang, Weipeng; Hua, Jianghuan; Lam, Paul K S; Lam, James C W; Zhou, Bingsheng

2018-05-02

Contamination from lower brominated PBDEs is ubiquitous in the environments. However, their effects on gut microbiota and intestinal health have not yet been investigated. This study exposed adult zebrafish to an environmentally realistic concentration of pentaBDE mixture (DE-71) at 5.0 ng/L for 7 days, after which metagenomic sequencing of the intestinal microbiome was conducted and host physiological activities in the intestine and liver were also examined. The results showed that acute exposure to DE-71 significantly shifted the gut microbial community in a sex-specific manner. Certain genera (e.g., Mycoplasma, Ruminiclostridium, unclassified Firmicutes sensu stricto, and Fusobacterium) disappeared from the DE-71-exposed intestines, resulting in decreased bacterial diversity. Bacterial metabolic functions in guts were also affected by DE-71, namely those covering energy metabolism, virulence, respiration, cell division, cell signaling, and stress response. In addition, measurement of diverse sensitive biomarkers showed that the health of male intestines was remarkably compromised by the DE-71 exposure, as indicated by the disruption to its neural signaling (serotonin), epithelial barrier integrity (tight junction protein 2), inflammatory response (interleukin 1β), oxidative stress and antioxidant capacity, as well as detoxifying potential (ethoxyresorufin-O-deethylase activity). However, female intestines maintained intact physiological activities. Compared to the direct impact on intestines, a latent effect of DE-71 was observed in livers. Co-occurrence network analysis demonstrated that the gut bacteria vigorously interacted to establish the fittest community under DE-71 stress by promoting the reproduction of favorable genera, while diminishing the survival of unfavorable ones. Significant correlations between the zebrafish gut microbiota and physiological activities (e.g., oxidative stress, detoxification, neurotransmission, and epithelial integrity) were also observed. Overall, this study has demonstrated, for the first time, the high susceptibility of gut microbiota and intestinal health of zebrafish to DE-71, thus warranting more work to reveal its mode of toxicity. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Design, Synthesis and Screening of Potential Pyridinium Oxime Prodrugs.

DTIC Science & Technology

1985-07-31

copper sulfate pentahydrate , and 15 g (87 mol) of the mixture of bromo- picolines 13c and 131. The combined reactions produced 27 g (96%) of a brown...extracted with ethyl ether. The ether extracts were washed with brine, dried with sodium sulfate , filtered and flashed. The residue was then purified by...stirring to the reaction mix. The addition was exothermic as the copper complexes decomposed. The cooled mixture was extracted with several 20 ml

Neurobehavioral, Hormonal, and Reproductive Effects following Developmental Exposure to a Commercial PBDE Mixture, DE-71

EPA Science Inventory

Developmental effects caused by PBDEs have been suspected due to their chemically structural similarities to polychlorinated biphenyls (PCBs). This study evaluated neurobehavioral, hormonal, and reproductive effects in rat offspring perinatally exposed to a widely used pentabromi...

NIOSH Manual of Analytical Methods (third edition). Fourth supplement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-08-15

The NIOSH Manual of Analytical Methods, 3rd edition, was updated for the following chemicals: allyl-glycidyl-ether, 2-aminopyridine, aspartame, bromine, chlorine, n-butylamine, n-butyl-glycidyl-ether, carbon-dioxide, carbon-monoxide, chlorinated-camphene, chloroacetaldehyde, p-chlorophenol, crotonaldehyde, 1,1-dimethylhydrazine, dinitro-o-cresol, ethyl-acetate, ethyl-formate, ethylenimine, sodium-fluoride, hydrogen-fluoride, cryolite, sodium-hexafluoroaluminate, formic-acid, hexachlorobutadiene, hydrogen-cyanide, hydrogen-sulfide, isopropyl-acetate, isopropyl-ether, isopropyl-glycidyl-ether, lead, lead-oxide, maleic-anhydride, methyl-acetate, methyl-acrylate, methyl-tert-butyl ether, methyl-cellosolve-acetate, methylcyclohexanol, 4,4'-methylenedianiline, monomethylaniline, monomethylhydrazine, nitric-oxide, p-nitroaniline, phenyl-ether, phenyl-ether-biphenyl mixture, phenyl-glycidyl-ether, phenylhydrazine, phosphine, ronnel, sulfuryl-fluoride, talc, tributyl-phosphate, 1,1,2-trichloro-1,2,2-trifluoroethane, trimellitic-anhydride, triorthocresyl-phosphate, triphenyl-phosphate, and vinyl-acetate.

DEVELOPMENTAL EVALUATIONS OF C57BL/6 MICE EXPOSED TO 2,2',4,4'-BROMINATED DIPHENYL ETHER (DE47) ON POSTNATAL DAY 10.

EPA Science Inventory

Polybrominated diphenyl ethers (PBDEs) are widely used commercial flame retardants that are accumulating in the environment. 2,2',4,4'-Brominated diphenyl ether (DE47) is the most stable congener of this group and is undergoing the most rapid accumulation in humans, despite the ...

Application of a constant hole volume Sanchez-Lacombe equation of state to mixtures relevant to polymeric foaming.

PubMed

von Konigslow, Kier; Park, Chul B; Thompson, Russell B

2018-06-06

A variant of the Sanchez-Lacombe equation of state is applied to several polymers, blowing agents, and saturated mixtures of interest to the polymer foaming industry. These are low-density polyethylene-carbon dioxide and polylactide-carbon dioxide saturated mixtures as well as polystyrene-carbon dioxide-dimethyl ether and polystyrene-carbon dioxide-nitrogen ternary saturated mixtures. Good agreement is achieved between theoretically predicted and experimentally determined solubilities, both for binary and ternary mixtures. Acceptable agreement with swelling ratios is found with no free parameters. Up-to-date pure component Sanchez-Lacombe characteristic parameters are provided for carbon dioxide, dimethyl ether, low-density polyethylene, nitrogen, polylactide, linear and branched polypropylene, and polystyrene. Pure fluid low-density polyethylene and nitrogen parameters exhibit more moderate success while still providing acceptable quantitative estimations. Mixture estimations are found to have more moderate success where pure components are not as well represented. The Sanchez-Lacombe equation of state is found to correctly predict the anomalous reversal of solubility temperature dependence for low critical point fluids through the observation of this behaviour in polystyrene nitrogen mixtures.

Densities and viscosities for binary mixtures of N-methyldiethanolamine + triethylene glycol monomethyl ether from 25 C to 70 C and N-methyldiethanolamine + ethanol mixtures at 40 C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henni, A.; Maham, Y.; Tontiwachwuthikul, P.

2000-04-01

Recent studies done on the absorption and desorption of acid gases (CO{sub 2}, H{sub 2}S) from natural gas, petroleum, and ammonia synthesis streams have shown that aqueous solutions of N-methyldiethanolamine (MDEA) can be used effectively for the selective removal of H{sub 2}S. This paper reports the measured values of the density and viscosity of binary mixtures of N-methyldiethanolamine (MDEA) and triethylene glycol monomethyl ether (TEGMME) at five temperatures in the range 25 C to 70 C over the whole concentration range. The authors also report the density and viscosity of the binary mixture MDEA + ethanol at 40 C. Themore » results are compared with data for aqueous mixtures and other alkanolamines when these are available. The derived excess molar volumes and viscosity deviations were correlated as a function of composition. The Grunberg-Nissan interaction energy constants are also reported.« less

Fractionation of technical octabromodiphenyl ether by countercurrent chromatography combined with gas chromatography/mass spectrometry and offline and online (1)H nuclear magnetic resonance spectroscopy.

PubMed

Hammann, Simon; Conrad, Jürgen; Vetter, Walter

2015-06-12

Countercurrent chromatography (CCC) is a technique, which uses two immiscible liquid phases for a separation process in a long and hollow tube. The technique allows the separation of high amounts of sample (50mg to several grams) with a low consumption of solvents. In this study, we fractionated 50mg technical octabromodiphenyl ether (DE-79) and analyzed the fractions by gas chromatography with mass spectrometry (GC/MS) and proton nuclear magnetic resonance ((1)H NMR) spectroscopy. CCC separations were performed with n-hexane/acetonitrile as solvent system in tail-to-head (i.e. the upper phase is mobile) mode. Twelve CCC fractions were studied for the PBDE composition. CCC elution of PBDE congeners was dependent both on the degree of bromination and substitution pattern. Higher brominated congeners eluted faster than lower brominated congeners and isomers with vicinal hydrogen atoms eluted last. In addition to several known PBDE congeners in DE-79, we were able to unequivocally identify BDE 195 in DE-79 and we could verify the presence of BDE 184. Finally, we also established the online hyphenation of CCC with (1)H NMR. The use of deuterated solvents could be avoided by using n-hexane/acetonitrile as two-phase system. By online CCC-(1)H NMR in stop-flow mode we were able to detect eight PBDE congeners in the mixture. Copyright © 2015 Elsevier B.V. All rights reserved.

Chemical Aspects of General Anesthesia: Part 1. From Ether to Halothane

ERIC Educational Resources Information Center

Brunsvold, Robert; Ostercamp, Daryl L.

2006-01-01

The history and evolution of general anesthesia, which invokes a variety of drugs, each compound having a specific purpose from muscle relaxation to unconsciousness is discussed. Some of the popular anesthetics discussed are ether, chloroform, halocarbons, gaseous nitrous oxide, halothane, and mixture of 70% nitrous oxide and 30% oxygen.

TOXICOKINETICS OF BDE 47 IN FEMALE MICE: EFFECT OF DOSE, ROUTE OF EXPOSURE, AND TIME

EPA Science Inventory

2,2',4,4'-Tetrabromodiphenyl ether (BDE 47) is present in commercial mixtures of polybrominated diphenyl ethers (PBDEs) which are used as flame retardants in a wide variety of consumer products. Despite its small contribution to PBDE global production and usage, BDE 47 is the ma...

Potential Replacements for Solvents that are Ozone Depleting Substances

DTIC Science & Technology

1994-09-01

18.4 d-Lumonene 17.8 Glidsafe-LUI54B 18.2 Turpentine 16.5 isobutyl acetate 17.2 Diisobutyl phthalate 18.3 Dipropylene glycol monomethyl ether 19.0...Diethylene glycol monomethyl ether 22.3 N- Methyl pyrrolidone 23.0 Water 47.8 1. Barton (1983): 2. Gallagher (date unknown). 9 TI DSTO-TR-0046 For blends...parameters. For example, Glidsafe UTS-4B which is a mixture of terpenes and dipropylene glycol monomethyl ether has a Hildebrand solubility of 18.2 MPal/ 2

PBDES: TOXICOLOGY UPDATE

EPA Science Inventory

Polybrominated diphenyl ethers (PBDEs) have been major commercial products used as flame retardants. While two of the commercial mixtures, Penta and Octa, have either been withdrawn or banned in Europe and the US respectively, the largest volume mixture, Deca, continues to be wi...

Larval susceptibility of Aloe barbadensis and Cannabis sativa against Culex quinquefasciatus, the filariasis vector.

PubMed

Maurya, Prejwltta; Mohan, Lalit; Sharma, Preeti; Srivastava, C N

2008-11-01

Larvicidal potential of petroleum ether, carbon tetrachloride and methanol extracts of Aloe barbadensis and Cannabis sativa has been investigated against Culex quinquefasciatus. Among the extracts examined, Carbon tetrachloride extract (Cte) of Aloe barbadensis was the most effective with LC50 values of 15.31 and 11.01 ppm after 24 and 48 hr of exposure, respectively followed by pertoleum ether extract (Pee) of A barbadensis, Cte of C. sativa, methanol extract (Mee) of A. barbadensis, methanol and petroleum ether of C. saliva, LC, being 25.97, 88.51, 144.44, 160.78 and 294.42 ppm affer 24hr and 16.60, 68.69, 108.38, 71.71 and 73.32 ppm after 48 hr of post treatment, respectively. Cte of both the plants exhibits potential larvicidal activity and can be used as ecofriendly alternative in the management of the filariasis vector, Culex quinquefasciatus.

DETERMINATION OF SURFACTANT SODIUM LAURYL ETHER SULFATE BY ION PAIRING CHROMATOGRAPHY WITH SUPPRESSED CONDUCTIVITY DETECTION

EPA Science Inventory

A method for the determination of the anionic Steol CS-330 surfactant is described. CS-330 is a complex mixture of oligomers due to the various sizes of fatty alcohols and the number of moles of the ethoxylation. The main component of CS-330 is sodium lauryl ether sulfate (SLES)....

Efficacy of pinosylvins against white-rot and brown-rot fungi

Treesearch

Catherine C. Celimene; Jessie A. Micales; Leslie Ferge; Raymond A. Young

1999-01-01

Three stilbenes, pinosylvin (PS), pinosylvin monomethyl ether (PSM) and pinosylvin dimethyl ether (PSD), were extracted from white spruce (Picea glauca), jack pine (Pinus banksiana), and red pine (Pinus resinosa) pine cones, and their structures were confirmed by spectroscopic and chromatographic (HPLC, GC/MS, NMR and FTIR) analysis. PS, PSM, PSD or a 1:1:1 mixture of...

LACK OF ALTERATIONS IN THYROID HORMONES FOLLOWING EXPOSURE TO POLYBROMINATED DIPHENYL ETHER 47 DURING A PERIOD OF RAPID BRAIN DEVELOPMENT IN MICE

EPA Science Inventory

Polybrominated diphenyl ether 47 (PBDE-47) is one of a class of commonly used flame retardants that are accumulating in the environment, including human tissues. There are reports of thyroid alterations following exposure to PBDE mixtures, and it is possible that disruptions in t...

Explosion characteristics of flammable organic vapors in nitrous oxide atmosphere.

PubMed

Koshiba, Yusuke; Takigawa, Tomihisa; Matsuoka, Yusaku; Ohtani, Hideo

2010-11-15

Despite unexpected explosion accidents caused by nitrous oxide have occurred, few systematic studies have been reported on explosion characteristics of flammable gases in nitrous oxide atmosphere compared to those in air or oxygen. The objective of this paper is to characterize explosion properties of mixtures of n-pentane, diethyl ether, diethylamine, or n-butyraldehyde with nitrous oxide and nitrogen using three parameters: explosion limit, peak explosion pressure, and time to the peak explosion pressure. Then, similar mixtures of n-pentane, diethyl ether, diethylamine, or n-butyraldehyde with oxygen and nitrogen were prepared to compare their explosion characteristics with the mixtures containing nitrous oxide. The explosion experiments were performed in a cylindrical vessel at atmospheric pressure and room temperature. The measurements showed that explosion ranges of the mixtures containing nitrous oxide were narrow compared to those of the mixtures containing oxygen. On the other hand, the maximum explosion pressures of the mixtures containing nitrous oxide were higher than those of the mixtures containing oxygen. Moreover, our experiments revealed that these mixtures differed in equivalence ratios at which the maximum explosion pressures were observed: the pressures of the mixtures containing nitrous oxide were observed at stoichiometry; in contrast, those of the mixtures containing oxygen were found at fuel-rich area. Chemical equilibrium calculations confirmed these behaviors. Copyright © 2010 Elsevier B.V. All rights reserved.

Environmental analysis of higher brominated diphenyl ethers and decabromodiphenyl ethane.

PubMed

Kierkegaard, Amelie; Sellström, Ulla; McLachlan, Michael S

2009-01-16

Methods for environmental analysis of higher brominated diphenyl ethers (PBDEs), in particular decabromodiphenyl ether (BDE209), and the recently discovered environmental contaminant decabromodiphenyl ethane (deBDethane) are reviewed. The extensive literature on analysis of BDE209 has identified several critical issues, including contamination of the sample, degradation of the analyte during sample preparation and GC analysis, and the selection of appropriate detection methods and surrogate standards. The limited experience with the analysis of deBDethane suggests that there are many commonalities with BDE209. The experience garnered from the analysis of BDE209 over the last 15 years will greatly facilitate progress in the analysis of deBDethane.

Partial Molar Volumes of 15-Crown-5 Ether in Mixtures of N,N-Dimethylformamide with Water.

PubMed

Tyczyńska, Magdalena; Jóźwiak, Małgorzata

2014-01-01

The density of 15-crown-5 ether (15C5) solutions in the mixtures of N,N -dimethylformamide (DMF) and water (H 2 O) was measured within the temperature range 293.15-308.15 K using an Anton Paar oscillatory U-tube densimeter. The results were used to calculate the apparent molar volumes ( V Φ ) of 15C5 in the mixtures of DMF + H 2 O over the whole concentration range. Using the apparent molar volumes and Redlich and Mayer equation, the standard partial molar volumes of 15-crown-5 were calculated at infinite dilution ([Formula: see text]). The limiting apparent molar expansibilities ( α ) were also calculated. The data are discussed from the point of view of the effect of concentration changes on interactions in solution.

High energy electron beam curing of epoxy resin systems incorporating cationic photoinitiators

DOEpatents

Janke, C.J.; Lopata, V.J.; Havens, S.J.; Dorsey, G.F.; Moulton, R.J.

1999-03-02

A mixture of epoxy resins such as a semi-solid triglycidyl ether of tris (hydroxyphenyl) methane and a low viscosity bisphenol A glycidyl ether and a cationic photoinitiator such as a diaryliodonium salt is cured by irradiating with a dosage of electron beams from about 50 to about 150 kGy, forming a cross-linked epoxy resin polymer.

High energy electron beam curing of epoxy resin systems incorporating cationic photoinitiators

DOEpatents

Janke, Christopher J.; Lopata, Vincent J.; Havens, Stephen J.; Dorsey, George F.; Moulton, Richard J.

1999-01-01

A mixture of epoxy resins such as a semi-solid triglycidyl ether of tris (hydroxyphenyl) methane and a low viscosity bisphenol A glycidyl ether and a cationic photoinitiator such as a diaryliodonium salt is cured by irradiating with a dosage of electron beams from about 50 to about 150 kGy, forming a cross-linked epoxy resin polymer.

In vitro study comparing the ability of mono-octanoin and mono-octanoin plus methyl tert-butyl ether to dissolve biliary stones.

PubMed

Tritapepe, R; Cesana, B

1996-01-01

This in vitro study compared the gallstone dissolution rates of mono-octanoin, mono-octanoin plus 10% distilled water, and mono-octanoin plus methyl tert-butyl ether 2:1. Sixteen stones were treated with each solvent at a slow perfusion rate of 3-4 ml/h and a rapid perfusion rate of 2.5 ml/30 min with 20-sec instillation/aspiration cycles, both with and without bile. The stones were weighed before, and 3, 6, 12 and 24 hrs after the start of treatment: the solvent was changed every 30 min. After 24 hrs of instillation/aspiration without bile, the mono-octanoin/methyl tert-butyl ether mixture reduced the weight of the stones by 93%, mono-octanoin plus water by 63%, and mono-octanoin alone by 52%; with bile, the figures were, respectively, 86%, 42% and 40%. The mono-octanoin/methyl tert-butyl ether mixture thus took approximately half the time needed by the other two preparations to dissolve the stones to the same extent, a finding which may be relevant for the clinical dissolution of bile duct stones.

Anti-Helicobacter pylori activity of derivatives of the phthalide-containing antibacterial agents spirolaxine methyl ether, CJ-12,954, CJ-13,013, CJ-13,102, CJ-13,104, CJ-13,108 and CJ-13,015.

PubMed

Radcliff, Fiona J; Fraser, John D; Wilson, Zoe E; Heapy, Amanda M; Robinson, James E; Bryant, Christina J; Flowers, Christopher L; Brimble, Margaret A

2008-06-01

The naturally occurring phthalide-containing antibiotics spirolaxine methyl ether, CJ-12,954, CJ-13,013, CJ-13,015, CJ-13,102, CJ-13,103, CJ-13,104 and CJ-13,108, have been reported to exhibit anti-H. pylori activity. However, the exact stereochemistry of spirolaxine methyl ether, CJ-12,954 or CJ-13,013, contributing to this observed activity has not been confirmed. The anti-H. pylori activity of several analogues of spirolaxine methyl ether, CJ-12,954 and CJ-13,013 of defined stereochemistry together with the anti-H. pylori activity of several indole analogues of the simpler phthalide-containing antibiotics CJ-13,102, CJ-13,104, CJ-13,108 and CJ-13,015 is reported herein. A 1:1 mixture of spiroacetals 5b and 6b in which the phthalide substituent exhibited (3R)-stereochemistry was sixty times more active than the corresponding 1:1 mixture of spiroacetals with (3S)-stereochemistry. Notably, the unnatural (2''S)-diastereomer of spirolaxine methyl ether exhibited more potent anti-H. pylori activity than the natural product spirolaxine methyl ether. The 4,6-dimethoxyindoles 9, 10, 11 and 13 were all found to be less active than their parent compounds 1, 2, 3 and 4, respectively. Chain-shortened 4,6-dimethoxyindole analogue 12 of CJ-13,108 3 and 4,6-dimethoxyindole-spiroacetal 13 exhibited weak anti-H. pylori activity thus providing future opportunity for drug discovery programs.

Reductive Etherification of Fatty Acids or Esters with Alcohols using Molecular Hydrogen.

PubMed

Erb, Benjamin; Risto, Eugen; Wendling, Timo; Gooßen, Lukas J

2016-06-22

In the presence of a catalyst system consisting of a ruthenium/triphos complex and the Brønsted acid trifluoromethanesulfonimide, mixtures of fatty acids and aliphatic alcohols are converted into the corresponding ethers at 70 bar H2 . The protocol allows the sustainable one-step synthesis of valuable long-chain ether fragrances, lubricants, and surfactants from renewable sources. The reaction protocol is extended to various fatty acids and esters both in pure form and as mixtures, for example, tall oil acids or rapeseed methyl ester (RME). Even the mixed triglyceride rapeseed oil was converted in one step. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

AFOSR Technical Report Summaries, April-June 1986,

DTIC Science & Technology

1986-06-01

C1HARGE DENSITY. ELECTRODES. INTERrACIAL TENSION. PRESSURE, SIIRFACE PROPERTIES. CORROSION INHIBITION, MOLECULES, ORGANIC COMPOUNDS . SORPTION . FILMS... Perfluorinated derivatives of hydrocarbon Compounds usually ewhibit different propeties than their hydrocarbon analogues. The perfluoro crown ether-s are m.arkedly...Binary Hydrocarbon Mixtures, AD-A166 130 Materials for Emergency Repair AD-A167 094 of Runways. -BROMINE COMPOUNDS AD-Ai64 225 tCHEMICAL LASERS Analysis of

FTIR cryospectroscopic and ab initio studies of desflurane-dimethyl ether H-bonded complexes.

PubMed

Melikova, S M; Rutkowski, K S; Rospenk, M

2017-09-05

The IR spectra of mixtures of desflurane and dimethyl ether are studied with the help of FTIR cryospectroscopy in liquefied Kr at T~118-158K. Comparative analysis of the experimental data and results of ab initio calculations show that either of the two C-H groups of desflurane is involved in heterodimer formation of comparable strengths. The blue frequency shift is found for stretching vibrations of those C-H donors which directly participate in H-bond formation. Additionally the complexes are stabilized by weaker contacts between hydrogen atoms of dimethyl ether and fluorine atoms of desflurane. Copyright © 2017 Elsevier B.V. All rights reserved.

RECOVERY OF URANIUM FROM PITCHBLENDE

DOEpatents

Ruehle, A.E.

1958-06-24

The decontamination of uranium from molybdenum is described. When acid solutions containing uranyl nitrate are contacted with ether for the purpose of extracting the uranium values, complex molybdenum compounds are coextracted with the uranium and also again back-extracted from the ether with the uranium. This invention provides a process for extracting uranium in which coextraction of molybdenum is avoided. It has been found that polyhydric alcohols form complexes with molybdenum which are preferentially water-soluble are taken up by the ether extractant to only a very minor degree. The preferred embodiment of the process uses mannitol, sorbitol or a mixture of the two as the complexing agent.

Catalytic and electrocatalytic hydrogenolysis of brominated diphenyl ethers.

PubMed

Bonin, Pascale M L; Edwards, Patrick; Bejan, Dorin; Lo, Chun Chi; Bunce, Nigel J; Konstantinov, Alexandre D

2005-02-01

Polybrominated diphenyl ethers (PBDEs) are ubiquitous environmental contaminants due to their use as additive flame-retardants. Conventional catalytic hydrogenolysis in methanol solution and electrocatalytic hydrogenolysis in aqueous methanol were examined as methods for debrominating mono- and di-bromodiphenyl ethers, as well as a commercial penta-PBDE mixture, in each case using palladium on alumina as the catalyst. Electrocatalytic hydrogenolysis employed a divided flow-through batch cell, with reticulated vitreous carbon cathodes and IrO2/Ti dimensionally stable anodes. Both methods gave efficient sequential debromination, with essentially complete removal of bromine from the PBDEs, but the electrocatalytic method was limited by the poor solubility of PBDEs in aqueous methanol.

Bioavailability and mass balance studies of a commercial pentabromodiphenyl ether mixture in male Sprague-Dawley rats.

PubMed

Huwe, Janice; Hakk, Heldur; Lorentzsen, Margaret

2007-01-01

Polybrominated diphenyl ethers (PBDE) are common flame retardants used in polyurethane foam, high impact polystyrene, and textiles which appear to be increasing in the environment and biota. Two PBDE congeners that are particularly prominent in environmental samples are 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) and 2,2',4,4',5-pentabromodiphenyl ether (BDE-99). These two congeners are major components in penta-BDE formulations which constitute a minor percentage of the commercial PBDE market. In order to determine the bioavailability and bioconcentration potential of these PBDEs, we have conducted a feeding experiment in rats, dosing with low amounts of a commercial penta-BDE mixture for 21 days to mimic an environmental exposure. The carcasses, livers, and feces from control and dosed rats were quantitated for PBDEs by a high resolution GC-MS isotope dilution method. Between 25% and 50% of each of the dosed congeners was retained in the rats with the liver being a minor depot (<1% of the dose). Fecal excretion accounted for 4-12% of the dosed congeners. A large percent of the dose (40-60%) was not recovered indicating that metabolic transformations may have occurred in the rats. Hydroxylated metabolites were qualitatively identified in the feces and carcass by GC-MS. The relative congener distribution in each tissue was nearly identical to the congener distribution of the commercial mixture. Conclusions from the study suggest that the tetra- to hexa-BDEs present in commercial penta-BDE formulations are largely bioavailable, that bioavailability in the rat is not dependent on the degree of bromination, and that metabolism may occur to a large extent during a chronic exposure.

Ether bond effects in quaternary ammonium and phosphonium ionic liquid-propanol solutions

NASA Astrophysics Data System (ADS)

Kishimura, Hiroaki; Kohki, Erica; Nakada, Ayumu; Tamatani, Kentaro; Abe, Hiroshi

2018-03-01

The liquid-liquid equilibria (LLE) of quaternary ammonium and phosphonium ionic liquid (IL)-propanol solutions were examined. The ILs contained cations with or without ether bonds; the anion in all the ILs was bis(trifluoromethanesulfonyl)imide (TFSI-). The cations without ether groups are tributylmethyl ammonium (N4441+), triethylpentyl phosphonium (P2225+), triethyloctyl phosphonium (P2228+), and tributylmethyl phosphonium (P4441+). The cations containing ether groups are N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium, (N122(2O1)+), triethyl(methoxymethyl) phosphonium (P222(1O1)+), and triethyl(2-methoxyethyl) phosphonium, (P222(2O1)+). Propanol isomer effect was observed to affect the LLEs, reflecting the geometrical factors and hydrophobicities of 1-propanol and 2-propanol. According to Raman spectroscopy, the TFSI- anion conformers in the mixtures were altered in the presence of ether bonds in the cations. The universal quasichemical (UNIQUAC) interaction parameters are consistent with significant factors affecting IL-propanol solutions, such as the type of cation (ammonium or phosphonium), ether bonds, TFSI- conformers, and propanol isomer effects.

The influence of water-ethanol mixture on the thermodynamics of complex formation between 18-crown-6 ether and L-phenylalanine

NASA Astrophysics Data System (ADS)

Usacheva, T. R.; Sharnin, V. A.; Chernov, I. V.; Matteoli, E.; Terekhova, I. V.; Kumeev, R. S.

2012-08-01

The influence of water-ethanol mixture composition on the complex formation between 18-crown-6 ether and L-phenylalanine was studied by titration calorimetry at Т = 298.15 K. The standard thermodynamic parameters (ΔrGо, ΔrHо, ТΔrSо) of formation of [Phe18C6] molecular complex were calculated from data obtained by means of the microcalorimetric system TAM III (TA Instruments, USA) at X(EtOH) = 0.0/0.6 mol fraction. The stability of [Phe18C6] and the mechanism of complexation in water were investigated using the 1Н and 13С NMR spectroscopy. The increase of EtOH concentration results in an increase of the complex stability and of the exothermicity of complexation.

Phase Behavior of Binary Mixture of Heptaethylene Glycol Decyl Ether and Water: Formation of Phase Compound in Solid Phase

PubMed

Nibu; Suemori; Inoue

1997-07-01

Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) were used to construct and characterize the phase diagram for a binary mixture of heptaethylene glycol decyl ether (C10 E7 ) and water in the temperature range from -60 to 80°C. Plots of the endothermic peak temperatures obtained by DSC measurements against compositions provided eutectic solid-liquid phase boundaries with a eutectic composition of 34 wt% of H2 O. On the other hand, heat of fusion per unit weight of the mixture changed discretely at the composition corresponding to the "eutectic" composition. Furthermore, the IR spectra obtained for the mixture in the solid phase were well reproduced as a superposition of those for the mixture of 34 wt% H2 O and pure components but were not reproduced by superimposing the spectra obtained for the solid surfactant and ice. These observations indicate that a solid phase compound is formed between C10 E7 and water with a stoichiometry of 1:14 and that the compound and pure components exist as separate phases, rather than the phases separating into surfactant and ice, which would be expected if the C10 E7 /water mixture formed a true eutectic mixture system. It is estimated from the composition corresponding to the phase compounds that two molecules of water per oxyethylene unit are bound to hydrophilic polyoxyethylene chain of C10 E7 to form a hydrated compound.

Alkyl Azides, Diazides, Haloazides and Bridged Polycyclic Diazides

DTIC Science & Technology

1991-05-16

temperature. Most of the methyl ether was removed during this process. The ehtyl ether was distilled from the reaction mixture using a water aspirator into a...Street PROGRAM IPROJECT ITASK IWORK li1111? ArliiqIoh, VA 22217-5000 EILIMENT NO I NO. I oACCESSION P10) Alkyl Azides, Dlazides, laloazides and...REPRODUCE LEGIBLY. ALKYL AZIDES, DIAZIDES, HALOAZIDES AND BRIDGED POLYCYCLIC DIAZIDES Final REPORTe July 1, 1989-November 14, 1990 A6jd.%4gi0 F’or

Mass spectrometer calibration standard

NASA Technical Reports Server (NTRS)

Ross, D. S.

1978-01-01

Inert perfluorinated alkane and alkyl ethers mixture is used to calibrate mass spectrometer. Noncontaminating, commercially-available liquid provides series of reproducible reference peaks over broad mass spectrum that ranges over mass numbers from 1 to 200.

Electrochemistry for biofuel generation: transformation of fatty acids and triglycerides to diesel-like olefin/ether mixtures and olefins.

PubMed

dos Santos, Tatiane R; Harnisch, Falk; Nilges, Peter; Schröder, Uwe

2015-03-01

Electroorganic synthesis can be exploited for the production of biofuels from fatty acids and triglycerides. With Coulomb efficiencies (CE) of up to 50 %, the electrochemical decarboxylation of fatty acids in methanolic and ethanolic solutions leads to the formation of diesel-like olefin/ether mixtures. Triglycerides can be directly converted in aqueous solutions by using sonoelectrochemistry, with olefins as the main products (with a CE of more than 20 %). The latter reaction, however, is terminated at around 50 % substrate conversion by the produced side-product glycerol. An energy analysis shows that the electrochemical olefin synthesis can be an energetically competitive, sustainable, and--in comparison with established processes--economically feasible alternative for the exploitation of fats and oils for biofuel production. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Process to convert biomass and refuse derived fuel to ethers and/or alcohols

DOEpatents

Diebold, James P.; Scahill, John W.; Chum, Helena L.; Evans, Robert J.; Rejai, Bahman; Bain, Richard L.; Overend, Ralph P.

1996-01-01

A process for conversion of a feedstock selected from the group consisting of biomass and refuse derived fuel (RDF) to provide reformulated gasoline components comprising a substantial amount of materials selected from the group consisting of ethers, alcohols, or mixtures thereof, comprising: drying said feedstock; subjecting said dried feedstock to fast pyrolysis using a vortex reactor or other means; catalytically cracking vapors resulting from said pyrolysis using a zeolite catalyst; condensing any aromatic byproduct fraction; catalytically alkylating any benzene present in said vapors after condensation; catalytically oligomerizing any remaining ethylene and propylene to higher olefins; isomerizing said olefins to reactive iso-olefins; and catalytically reacting said iso-olefins with an alcohol to form ethers or with water to form alcohols.

Investigation of HCCI Combustion of Diethyl Ether and Ethanol Mixtures Using Carbon 14 Tracing and Numerical Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mack, J H; Dibble, R W; Buchholz, B A

2004-01-16

Despite the rapid combustion typically experienced in Homogeneous Charge Compression Ignition (HCCI), components in fuel mixtures do not ignite in unison or burn equally. In our experiments and modeling of blends of diethyl ether (DEE) and ethanol (EtOH), the DEE led combustion and proceeded further toward completion, as indicated by {sup 14}C isotope tracing. A numerical model of HCCI combustion of DEE and EtOH mixtures supports the isotopic findings. Although both approaches lacked information on incompletely combusted intermediates plentiful in HCCI emissions, the numerical model and {sup 14}C tracing data agreed within the limitations of the single zone model. Despitemore » the fact that DEE is more reactive than EtOH in HCCI engines, they are sufficiently similar that we did not observe a large elongation of energy release or significant reduction in inlet temperature required for light-off, both desired effects for the combustion event. This finding suggests that, in general, HCCI combustion of fuel blends may have preferential combustion of some of the blend components.« less

Immiscible Systems

ERIC Educational Resources Information Center

Eckelmann, Jens; Luning, Ulrich

2013-01-01

layers of liquids. The setup of both demonstrations is such that one homogeneous layer in a multiphasic mixture separates into two new layers upon shaking. The solvents used are methanol, toluene, petroleum ether or "n"-pentane, silicone oil, perfluoroheptanes,…

Composition of zeotropic mixtures having predefined temperature glide

DOEpatents

Mahmoud, Ahmad M.; Lee, Jaeseon; Luo, Dong

2015-05-26

A composition of a zeotropic mixture has a first chemical constituent and at least one second, different chemical constituent. The zeoptropic mixture has a temperature glide of 5.degree. C.-25.degree. C. with regard to its saturated vapor temperature and its saturated liquid temperature. The first chemical constituent is selected from 1,1,1,3,3-pentafluoropropane, 1,1,2,2,3-pentafluoropropane, 1,1,1,3,3-pentafluorobutane, methyl perfluoropropyl ether, 1,1,1,2,3,3-hexafluoropropane and 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone.

Design, Fabrication, Characterization and Modeling of Integrated Functional Materials

DTIC Science & Technology

2009-10-01

cobalt ferrite (CoFe2O4) nanoparticles dispersed in a low-loss commercial polymer matrix obtained from Rogers Corporation. 2 mmol of Cobalt (II...oleylamine and 20 ml benzyl ether were added to the Iron (III) acetylacetonate and Cobalt (II) acetylacetonate mixture. The mixture was stirred...microwave applications Multiferroic bilayers of Cobalt Ferrite and PZT: The objective of this project is to fabricate bilayers of ferroelectric

Catalytic distillation process

DOEpatents

Smith, Jr., Lawrence A.

1982-01-01

A method for conducting chemical reactions and fractionation of the reaction mixture comprising feeding reactants to a distillation column reactor into a feed zone and concurrently contacting the reactants with a fixed bed catalytic packing to concurrently carry out the reaction and fractionate the reaction mixture. For example, a method for preparing methyl tertiary butyl ether in high purity from a mixed feed stream of isobutene and normal butene comprising feeding the mixed feed stream to a distillation column reactor into a feed zone at the lower end of a distillation reaction zone, and methanol into the upper end of said distillation reaction zone, which is packed with a properly supported cationic ion exchange resin, contacting the C.sub.4 feed and methanol with the catalytic distillation packing to react methanol and isobutene, and concurrently fractionating the ether from the column below the catalytic zone and removing normal butene overhead above the catalytic zone.

Catalytic distillation process

DOEpatents

Smith, L.A. Jr.

1982-06-22

A method is described for conducting chemical reactions and fractionation of the reaction mixture comprising feeding reactants to a distillation column reactor into a feed zone and concurrently contacting the reactants with a fixed bed catalytic packing to concurrently carry out the reaction and fractionate the reaction mixture. For example, a method for preparing methyl tertiary butyl ether in high purity from a mixed feed stream of isobutene and normal butene comprising feeding the mixed feed stream to a distillation column reactor into a feed zone at the lower end of a distillation reaction zone, and methanol into the upper end of said distillation reaction zone, which is packed with a properly supported cationic ion exchange resin, contacting the C[sub 4] feed and methanol with the catalytic distillation packing to react methanol and isobutene, and concurrently fractionating the ether from the column below the catalytic zone and removing normal butene overhead above the catalytic zone.

Extraction processes and solvents for recovery of cesium, strontium, rare earth elements, technetium and actinides from liquid radioactive waste

DOEpatents

Zaitsev, Boris N.; Esimantovskiy, Vyacheslav M.; Lazarev, Leonard N.; Dzekun, Evgeniy G.; Romanovskiy, Valeriy N.; Todd, Terry A.; Brewer, Ken N.; Herbst, Ronald S.; Law, Jack D.

2001-01-01

Cesium and strontium are extracted from aqueous acidic radioactive waste containing rare earth elements, technetium and actinides, by contacting the waste with a composition of a complex organoboron compound and polyethylene glycol in an organofluorine diluent mixture. In a preferred embodiment the complex organoboron compound is chlorinated cobalt dicarbollide, the polyethylene glycol has the formula RC.sub.6 H.sub.4 (OCH.sub.2 CH.sub.2).sub.n OH, and the organofluorine diluent is a mixture of bis-tetrafluoropropyl ether of diethylene glycol with at least one of bis-tetrafluoropropyl ether of ethylene glycol and bis-tetrafluoropropyl formal. The rare earths, technetium and the actinides (especially uranium, plutonium and americium), are extracted from the aqueous phase using a phosphine oxide in a hydrocarbon diluent, and reextracted from the resulting organic phase into an aqueous phase by using a suitable strip reagent.

Ternary mixtures of nitrile-functionalized glyme, non-flammable hydrofluoroether and fluoroethylene carbonate as safe electrolytes for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Liu, Yi; Fang, Shaohua; Shi, Pei; Luo, Dong; Yang, Li; Hirano, Shin-ichi

2016-11-01

New mixtures of 3-(2-methoxyethoxy)propanenitrile, fluoroethylene carbonate and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether are introduced as safe electrolytes for lithium-ion batteries. The electrolytes with 30 wt% 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether can own high safety and better wettability to separator and electrodes than the conventional electrolyte. The oxidation potentials of these electrolytes are about 4.8 V versus Li/Li+, and their conductivity can reach 5.42 mS cm-1 at 25 °C. Graphite/LiMn2O4 coin cells are used to evaluate the electrochemical performances, and this kind of safe electrolytes can exhibit better rate and cycle performances than the conventional electrolyte. These results indicate that such ternary electrolytes have a great potential for practical application.

Metal reduction at point-of-use filtration

NASA Astrophysics Data System (ADS)

Umeda, Toru; Daikoku, Shusaku; Varanasi, Rao; Tsuzuki, Shuichi

2016-03-01

We explored the metal removal efficiency of Nylon 6,6 and HDPE (High Density Polyethylene) membrane based filters, in solvents of varying degree of polarity such as Cyclohexanone and 70:30 mixture of PGME (Propylene Glycol Monomethyl Ether) and PGMEA (Propylene Glycol Monomethyl Ether), In all the solvents tested, Nylon 6,6 membrane filtration was found to be significantly more effective in removing metals than HDPE membranes, regardless of their respective membrane pore sizes. Hydrophilic interaction chromatography (HILIC) mechanism was invoked to rationalize metal removal efficiency dependence on solvent hydrophobicity.

Chemoselective Cleavage of p-Methoxybenzyl and 2-Naphthylmethyl Ethers Using a Catalytic Amount of HCl in Hexafluoro-2-propanol.

PubMed

Volbeda, Anne Geert; Kistemaker, Hans A V; Overkleeft, Herman S; van der Marel, Gijsbert A; Filippov, Dmitri V; Codée, Jeroen D C

2015-09-04

A new, fast, mild and chemoselective deprotection method to cleave p-methoxybenzyl and 2-naphthylmethyl ethers using catalytic amounts of hydrochloric acid in a 1:1 mixture of hexafluoro-2-propanol (HFIP) and methylene chloride (DCM) is described. The scope of the methodology becomes apparent from 14 examples of orthogonally protected monosaccharides that are subjected to HCl/HFIP treatment. The applicability of the HCl/HFIP method is illustrated by the synthesis of a sulfated β-mannuronic acid disaccharide.

Process to convert biomass and refuse derived fuel to ethers and/or alcohols

DOEpatents

Diebold, J.P.; Scahill, J.W.; Chum, H.L.; Evans, R.J.; Rejai, B.; Bain, R.L.; Overend, R.P.

1996-04-02

A process is described for conversion of a feedstock selected from the group consisting of biomass and refuse derived fuel (RDF) to provide reformulated gasoline components comprising a substantial amount of materials selected from the group consisting of ethers, alcohols, or mixtures thereof, comprising: drying said feedstock; subjecting said dried feedstock to fast pyrolysis using a vortex reactor or other means; catalytically cracking vapors resulting from said pyrolysis using a zeolite catalyst; condensing any aromatic byproduct fraction; catalytically alkylating any benzene present in said vapors after condensation; catalytically oligomerizing any remaining ethylene and propylene to higher olefins; isomerizing said olefins to reactive iso-olefins; and catalytically reacting said iso-olefins with an alcohol to form ethers or with water to form alcohols. 35 figs.

Lipase-catalyzed kinetic resolution of novel antitubercular benzoxazole derivatives.

PubMed

Łukowska-Chojnacka, Edyta; Kowalkowska, Anna; Napiórkowska, Agnieszka

2018-04-01

Novel benzoxazole derivatives were synthesized, and their antitubercular activity against sensitive and drug-resistant Mycobacterium tuberculosis strains (M. tuberculosis H 37 Rv, M. tuberculosis sp. 210, M. tuberculosis sp. 192, Mycobacterium scrofulaceum, Mycobacterium intracellulare, Mycobacterium fortuitum, Mycobacterium avium, and Mycobacterium kansasii) was evaluated. The chemical step included preparation of ketones, alcohols, and esters bearing benzoxazole moiety. All racemic mixtures of alcohols and esters were separated in Novozyme SP 435-catalyzed transesterification and hydrolysis, respectively. The transesterification reactions were carried out in various organic solvents (tert-butyl methyl ether, toluene, diethyl ether, and diisopropyl ether), and depending on the solvent, the enantioselectivity of the reactions ranged from 4 to >100. The enzymatic hydrolysis of esters was performed in 2 phase tert-butyl methyl ether/phosphate buffer (pH = 7.2) system and provided also enantiomerically enriched products (ee 88-99%). The antitubercular activity assay has shown that synthesized compounds exhibit an interesting antitubercular activity. Racemic mixtures of alcohols, (±)-4-(1,3-benzoxazol-2-ylsulfanyl)butan-2-ol ((±)-3a), (±)-4-[(5-bromo-1,3-benzoxazol-2-yl)sulfanyl]butan-2-ol ((±)-3b), and (±)-4-[(5,7-dibromo-1,3-benzoxazol-2-yl)sulfanyl]butan-2-ol ((±)-3c), displayed as high activity against M. scrofulaceum, M. intracellulare, M. fortuitum, and M. kansasii as commercially available antituberculosis drug-Isoniazid. Moreover, these compounds exhibited twice higher activity toward M. avium (MIC 12.5) compared with Isoniazid (MIC 50). © 2017 Wiley Periodicals, Inc.

Alteration of thyroid hormone concentrations in juvenile Chinook salmon (Oncorhynchus tshawytscha) exposed to polybrominated diphenyl ethers, BDE-47 and BDE-99.

PubMed

Arkoosh, Mary R; Van Gaest, Ahna L; Strickland, Stacy A; Hutchinson, Greg P; Krupkin, Alex B; Dietrich, Joseph P

2017-03-01

Polybrominated diphenyl ethers (PBDEs) have been used as flame-retardants in consumer products and are currently detected in salmon globally. The two most predominant PBDE congeners found in salmon are BDE-47 (2,2',4,4'-tetrabromodiphenyl ether) and BDE-99 (2,2',4,4',5-pentabromodiphenyl ether). In the present study, groups of juvenile Pacific Chinook salmon were fed five environmentally relevant concentrations of either BDE-47 (0.3-552 ng total PBDEs/g food), BDE-99 (0.3-580 ng total PBDEs/g food), or nearly equal mixtures of both congeners (0.7-690 ng total PBDEs/g food) for 39-40 days. The concentrations of circulating total thyroid hormones, thyroxine (T 4 ) and 3,5,3'-triiodothyronine (T 3 ), were measured using a hormone-specific time-resolved fluoroimmunoassay to determine if PBDE exposure disrupts the hypothalamic-pituitary-thyroid endocrine axis. The concentrations of both circulating T 4 and T 3 were altered in juvenile salmon by dietary uptake of BDE-99. Exposure to BDE-47 did not alter either T 3 or T 4 circulating hormone concentrations. However, exposure to a mixture of BDE-47 and BDE-99 reduced T 3 in fish with lower concentrations of total whole body PBDEs than with either congener alone at equivalent PBDE whole body concentrations. Accordingly, the disruption of PBDEs on circulating thyroid hormone concentrations has the potential to impact a number of critical functions in juvenile salmon including growth, parr-smolt transformation, and immunological processes. Published by Elsevier Ltd.

Evolution of mixed surfactant aggregates in solutions and at solid/solution interfaces

NASA Astrophysics Data System (ADS)

Zhang, Rui

Surfactant systems have been widely used in such as enhanced oil recovery, waste treatment and metallurgy, etc., in order to solve the problem of global energy crisis, to remove the pollutants and to generate novel energy resources. Almost all surfactant systems are invariably mixtures due to beneficial and economic considerations. The sizes and shapes of aggregates in solutions and at solid/solution interfaces become important, since the nanostructures of mixed aggregates determine solution and adsorption properties. A major hurdle in science is the lack of information on the type of complexes and aggregates formed by mixtures and the lack of techniques for deriving such information. Using techniques such as analytical ultracentrifuge, small angle neutron scattering, surface tension, fluorescence, cryo-TEM, light scattering and ultrafiltration, the nanostructures of aggregates of sugar based n-dodecyl-beta-D-maltoside (DM) and nonionic pentaethyleneglycol monododecyl ether or nonyl phenol ethoxylated decyl ether (NP-10) and their mixtures have been investigated to prove the hypothesis that the aggregation behavior is linked to packing of the surfactant governed by the molecular interactions as well as the molecular structures. The results from both sedimentation velocity and sedimentation equilibrium experiments suggest coexistence of two types of micelles in nonyl phenol ethoxylated decyl ether solutions and its mixtures with n-dodecyl-beta-D-maltoside while only one micellar species is present in n-dodecyl-beta-D-maltoside solutions, in good agreement with those from small angle neutron scattering, cryo-TEM, light scattering and ultrafiltration. Type I micelles were primary micelles at cmc while type II micelles were elongated micelles. On the other hand, the nanostructures of mixed surface aggregates have been quantitatively predicted for the first time using a modified packing index. As a continuation of the Somasundaran-Fuersteneau adsorption model, a modified one-step model has been developed to fully understand the adsorption behavior of surfactant mixtures and obtained thermodynamic information on aggregation number and standard free energy for surface aggregation. The findings are expected to provide fundamental basis for the design optimal surfactant schemes for desired purposes.

SIMULATION OF PERFORMANCE OF CHLORINE-FREE FLURORINATED ETHERS AND FLUORINATED HYDROCARBONS TO REPLACE CFC-11 AND CFC-114 IN CHILLERS

EPA Science Inventory

The paper discusses simulation of the performance of chlorine-free fluorinated ethers and fluorinated hydrocarbons as potential long-term replacements for CFC-11 and -114. Modeling has been done with in-house refrigeration models based on the Carnahan-Starling-DeSantis Equation o...

Modeling of multiple equilibria in the self-aggregation of di-n-decyldimethylammonium chloride/octaethylene glycol monododecyl ether/cyclodextrin ternary systems.

PubMed

Leclercq, Loïc; Lubart, Quentin; Aubry, Jean-Marie; Nardello-Rataj, Véronique

2013-05-28

The surface tension equations of binary surfactant mixtures (di-n-decyldimethylammonium chloride and octaethylene glycol monododecyl ether) are established by combining the Szyszkowski equation of surfactant solutions, the ideal or nonideal mixing theory, and the phase separation model. For surfactant mixtures, the surface tension at the air-water interface is calculated using nonideal theory due to synergism between the two adsorbed surfactant types. The incorporation of cyclodextrin complexation model to the surface tension equations gives a robust model for the description of the surface tension isotherms of binary, ternary, and more complex systems involving numerous inclusion complexes. The surface tension data obtained experimentally shows excellent agreement with the theoretical model below and above the formation of micelles. The strong synergistic effect observed between the two surfactants is disrupted by the presence of CDs, leading to ideal behavior of ternary systems. Indeed, depending on the nature of the cyclodextrin (i.e., α, β, or γ), which allows a tuning of the cavity size, the binding constants with the surfactants are modified as well as the surface properties due to strong modification of equilibria involved in the ternary mixture.

Destruction of decabromodiphenyl ether (BDE-209) in a ternary carbonate molten salt reactor.

PubMed

Yao, Zhi-tong; Li, Jin-hui; Zhao, Xiang-yang

2013-09-30

Soil contamination by PBDEs has become a significant environmental concern and requires appropriate remediation technologies. In this study, the destruction of decabromodiphenyl ether (BDE-209) in a ternary molten salt (Li, Na, K)2 CO3 reactor was evaluated. The effects of reaction temperature, additive amount of BDE-209 and salt mixture, on off-gas species, were investigated. The salt mixture after reaction was characterized by XRD analysis and a reaction pathway proposed. The results showed that the amounts of C2H6, C2H4, C4H8 and CH4 in the off-gas decreased with increases in temperature, while the CO2 level increased. When the reaction temperature reached 750 °C, incomplete combustion products (PICs) were no longer detected. Increasing BDE-209 loading was not helpful for the reaction, as more PICs were produced. Larger amounts of salt mixture were helpful for the reaction and PICs were not observed with the mole ratio 1: 2000 of BDE-209 to carbonate melt. XRD analysis confirmed the capture of bromine in BDE-209 by the molten salt. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of polyoxyethylene n-alkyl ethers on carrier-mediated transport of lanthanide ions through cellulose triacetate membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sugiura, Masaaki

1992-02-01

Fluxes of 14 kinds of lanthanides across cellulose triacetate membranes were determined by using mixtures of o-nitrophenyl n-octyl ether and a series of polyoxythylene n-alkyl ethers (POE ethers) as plasticizers, and hinokitiol as carrier. Effects of alkyl and polyoxyethylene (POE) chains of POE ether on the flux were demonstrated. The transport of the lanthanides was coupled to a flow of hydrogen ions. The POE ethers used (C{sub n}H{sub 2n+1}(OCH{sub 2}CH{sub 2}){sub x}OH, referred to as C{sub n}E{sub x}) were C{sub 10}E{sub 3}, C{sub 12}E{sub 3}, C{sub 14}E{sub 3}, C{sub 16}E{sub 3}, C{sub 12}E{sub 2}, C{sub 12}E{sub 4}, C{sub 12}E{sub 6}more » and C{sub 12}E{sub 8}, In all cases, high fluxes were observed for the lanthanides from samarium to lutetium. On the contrary, the fluxes for lanthanum to neodymium were extremely low. In experiments testing the effect of the alkyl chain, the order of the POE ethers in the lanthanide flux for samarium to lutetium was C{sub 12}E{sub 3} > C{sub 10}E{sub 3} > C{sub 14}E{sub 3} >C{sub 16}E{sub 3}. In experiments testing the effect of the POE chain, the flux decreased with an increase in the chain length.« less

Polyamideimides containing carbonyl and ether connecting groups

NASA Technical Reports Server (NTRS)

Havens, S. J.; Hergenrother, P. M.

1990-01-01

Polyamidenimides were prepared from the reaction of trimellitic anhydride chloride with seven diamines containing carbonyl and ether groups between the aromatic rings. Several of these polyamideimides were semicrystalline as evidenced by wide-angle X-ray diffraction and differential scanning calorimetry. Glass transition temperatures ranged between 187 and 245 C, and crystalline transition temperatures ranged between 317 and 416 C. A series of copolyamideimides from a mixture of 1,3-bis(4-aminophenoxy 4-prime-benzoyl) benzene and 1,4-bis(4-aminophenoxy 4-prime-benzoyl)benzene were similarly prepared. These copolyamideimides were semicrystalline and formed tough, solvent resistant films with good tensile properties.

SEPARATION OF URANIUM FROM THORIUM

DOEpatents

Hellman, N.N.

1959-07-01

A process is presented for separating uranium from thorium wherein the ratio of thorium to uranium is between 100 to 10,000. According to the invention the thoriumuranium mixture is dissolved in nitric acid, and the solution is prepared so as to obtain the desired concentration within a critical range of from 4 to 8 N with regard to the total nitrate due to thorium nitrate, with or without nitric acid or any nitrate salting out agent. The solution is then contacted with an ether, such as diethyl ether, whereby uranium is extracted into ihe organic phase while thorium remains in the aqueous phase.

Phosphorescence and Energy Transfer in Rigid Solutions.

ERIC Educational Resources Information Center

Enciso, E.; Cabello, A.

1980-01-01

Describes an experiment which illustrates the general aspects of intermolecular energy transfer between triplet states in rigid solutions of organic compounds solved in an ethanol-ether mixture. Measurements of quenching and energy transfer processes are made using the chemicals of benzophenone and naphthalene. (CS)

Brominated flame retardants, polychlorinated biphenyls, and organochlorine pesticides in captive giant panda (ailuropoda melanoleuca) and red panda (Ailurus fulgens) from China.

PubMed

Hu, Guo-Cheng; Luo, Xiao-Jun; Dai, Jia-Yin; Zhang, Xiu-Lan; Wu, Hua; Zhang, Cheng-Lin; Guo, Wei; Xu, Mu-Qi; Mai, Bi-Xian; Weit, Fu-Wen

2008-07-01

Organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and brominated flame retardants (BFRs) were investigated in captive giant and red panda tissues from China. The total concentrations of OCPs, PCBs, and polybrominated diphenyl ethers (PBDEs) in tissues ranged from 16.3 to 888 ng/g lipid weight (lw), 24.8 to 854 ng/g lw, and 16.4 to 2158 ng/g lw, respectively. p,p'-DDE and beta-HCH were major OCP contaminants. PCBs 99, 118, 153/132, 170, 180, and 209 were the major contributing congeners determined. Among PBDEs, congener BDE-209 was the most frequent and abundant, followed by BDE-206, BDE-208, BDE-207, BDE-203, BDE-47, and BDE-153. Decabromodiphenyl ethane (DeBDethane) was detected in 87 and 71% of the giant and red panda samples with concentrations up to 863 ng/g lw, respectively. The remarkable levels and dominance of BDE-209 and DeBDethane may relate to significant production, usage, or disposal of BFRs in China. The positive significant correlation between concentrations of PBDEs and PCBs in captive pandas may suggest that the exposure routes of PBDEs and PCBs to panda are similar. To our knowledge, this is the first report of the occurrence of DeBDethane in captive wildlife samples. Therefore, further studies are warranted to better understand DeBDethane production, transport, uptake, and toxicological effect.

40 CFR Table 1 to Subpart Dd of... - List of Hazardous Air Pollutants (HAP) for Subpart DD

Code of Federal Regulations, 2011 CFR

2011-07-01

... Methanol 0.855 74-83-9 Methyl bromide (Bromomethane) 1.000 74-87-3 Methyl chloride (Choromethane) 1.000 71... more common glycol ethers can be obtained by contacting the Waste and Chemical Processes Group, Office...

40 CFR Table 1 to Subpart Dd of... - List of Hazardous Air Pollutants (HAP) for Subpart DD

Code of Federal Regulations, 2010 CFR

2010-07-01

... Methanol 0.855 74-83-9 Methyl bromide (Bromomethane) 1.000 74-87-3 Methyl chloride (Choromethane) 1.000 71... more common glycol ethers can be obtained by contacting the Waste and Chemical Processes Group, Office...

Developmental Exposure to A Commercial PBDE Mixture: Effects on Protein Networks in the Cerebellum and Hippocampus of Rats

EPA Science Inventory

BACKGROUND: Polybrominated diphenyl ethers (PBDEs) are structurally similar topolychlorinated biphenyls (PCBs) and have both central (learning and memory deficits) and peripheral (motor dysfunction) neurotoxic effects at concentrations/doses similar to those of PCBs. The cellular...

IDENTIFICATION OF BIS(2-CHLOROETHYL) ETHER HYDROLYSIS PRODUCTS BY DIRECT AQUEOUS INJECTION GC/FT-IR

EPA Science Inventory

Gas chromatography coupled to Fourier-transform infrared spectroscopy (GC/FT-IR) is rapidly becoming an accepted analytical technique complementary to GC/mass spectroscopy for identifying organic compounds in mixtures at low to moderate concentrations. irect aqueous injection (DA...

Toughening of BIS maleimide resins: Synthesis and characterization of maleimide terminated poly(arylene ether) oligomers and polymers

NASA Technical Reports Server (NTRS)

Mcgrath, J. E.; Lyle, G. D.; Jurek, M. J.; Mohanty, D.; Hedrick, J. C.

1986-01-01

Amine functional poly(arylene ether) sulfones were previously reported. Herein, the chemistry was extended to amorphous poly(arylene ether) ketones because of their higher fracture toughness values, relative to the polysulfones. It was demonstrated that the amino functional oligomers undergo a self-crosslinking reaction at temperatures above about 220 C. This produces an insoluble, but ductile network that has excellent resistance. A ketamine structure hypothesis was proposed and verified using solid state magic angle NMR. In most cases, the water generated upon ketamine formation is too low to produce porosity and solid networks are obtained. The stability of the ketamine networks towards hydrolysis is excellent. The chemistry was further demonstrated to be able to crosslink preformed nonfunctional poly(arylene ether) ketones if a difunctional amine was utilized. This concept has the possibility of greatly improving the creep resistance of thermoplastics. Also, a new technique was developed for converting the amine functional oligomers cleanly into maleimide structures. This method involves reacting maleic anhydride with monomeric aminophenols in the presence of solvent mixtures.

SEPARATION OF URANIUM FROM THORIUM AND PROTACTINIUM

DOEpatents

Musgrave, W.K.R.

1959-06-30

This patent relates to the separation of uranium from thorium and protactinium; such mixtures of elements usually being obtained by neutron irradiation of thorium. The method of separating the constituents has been first to dissolve the mixture of elements in concertrated nitric acid and then to remove the protactinium by absorption on manganese dioxide and the uranium by solvent extraction with ether. Prior to now, comparatively large amounts of thorium were extracted with the uranium. According to the invention this is completely prevented by adding sodium diethyldithiocarbamate to the mixture of soluble nitrate salts. The organic salt has the effect of reacting only with the uranyl nitrate to form the corresponding uranyl salt which can then be selectively extracted from the mixture with amyl acetate.

Aggregation behavior of sodium lauryl ether sulfate with a positively bicharged organic salt and effects of the mixture on fluorescent properties of conjugated polyelectrolytes.

PubMed

Tang, Yongqiang; Liu, Zhang; Zhu, Linyi; Han, Yuchun; Wang, Yilin

2015-02-24

The aggregation behavior of anionic single-chain surfactant sodium lauryl ether sulfate containing three ether groups (SLE3S) with positively bicharged organic salt 1,2-bis(2-benzylammoniumethoxy)ethane dichloride (BEO) has been investigated in aqueous solution, and the effects of the BEO/SLE3S aggregate transitions on the fluorescent properties of anionic conjugated polyelectrolyte MPS-PPV with a larger molecular weight and cationic conjugated oligoelectrolyte DAB have been evaluated. Without BEO, SLE3S does not affect the fluorescent properties of MPS-PPV and only affects the fluorescent properties of DAB at a higher SLE3S concentration. With the addition of BEO, SLE3S and BEO form gemini-like surfactant (SLE3S)2-BEO. When the BEO/SLE3S molar ratio is fixed at 0.25, with increasing the BEO/SLE3S concentration, the BEO/SLE3S mixture forms large, loosely arranged aggregates and then transforms to closely packed spherical aggregates and finally to long thread-like micelles. The photoluminescence (PL) intensity of MPS-PPV varies with the morphologies of the BEO/SLE3S aggregates, while the PL intensity of DAB is almost independent of the aggregate morphologies. The results demonstrate that gemini-like surfactants formed through intermolecular interactions can effectively adjust the fluorescent properties of conjugated polyelectrolytes.

Abiotic Reductive Dechlorination of Tetrachloroethylene and Trichloroethylene in Anaerobic Environments

DTIC Science & Technology

2009-01-15

Measurement of Henry’s Law Constant for methyl tert-butyl ether Using Solid-phase Microextraction. Environmental Toxicology and Chemistry 2001, 20, 1625...and Environmental Microbiology 2005, 71, 3413-3419. Nirmalakhandan, N. N., R. E. Speece. QSAR Model for Predicting Henry’s Constant. Environmental

OCCURRENCE OF POLYBROMINATED BIPHENYLS, POLYBROMINATED DIBENZO-P-DIOXINS AND POLYBROMINATED DIBENZOFURANS AS IMPURITIES IN COMMERCIAL POLYBROMINATED DIPHENYL ETHER MIXTURES.

EPA Science Inventory

The objective of the present study is to determine the concentrations and compositions of polybrominated biphenyls (PBBs), polybrominated dibenzo-p-dioxins (PBDDs), and polybrominated dibenzofurans (PBDFs) as contaminants in the commercial polybrominated diphenylether (PBDE) mixt...

Variable mixture ratio performance through nitrogen augmentation

NASA Technical Reports Server (NTRS)

Beichel, R.; Obrien, C. J.; Bair, E. K.

1988-01-01

High/variable mixture ratio O2/H2 candidate engine cycles are examined for earth-to-orbit vehicle application. Engine performance and power balance information are presented for the candidate cycles relative to chamber pressure, bulk density, and mixture ratio. Included in the cycle screening are concepts where a third fluid (liquid nitrogen) is used to achieve a variable mixture ratio over the trajectory from liftoff to earth orbit. The third fluid cycles offer a very low risk, fully reusable, low operation cost alternative to high/variable mixture ratio bipropellant cycles. Variable mixture ratio engines with extendible nozzle are slightly lower performing than a single mixture ratio engine (MR = 7:1) with extendible nozzle. Dual expander engines (MR = 7:1) have slightly better performance than the single mixture ratio engine. Dual fuel dual expander engines offer a 16 percent improvement over the single mixture ratio engine.

Deetherification process

DOEpatents

Smith, Jr., Lawrence A.

1985-01-01

Ethers such as isobutyl tertiary butyl ether are dissociated into their component alcohols and isolefins by heat stabilized catalyst compositions prepared from nuclear sulfonic acid, for example, macroporous crosslinked polyvinyl aromatic compounds containing sulfonic acid groups are neutralized with a metal of Al, Fe, Zn, Cu, Ni, ions or mixtures and alkali, alkaline earth metals or ammonium ions by contacting the resin containing the sulfonic acid with aqueous solutions of the metals salts and alkali, alkaline earth metal or ammonium salts. The catalysts have at least 50% of the sulfonic acid groups neutralized with metal ions and the balance of the sulfonic acid groups neutralized with alkali, alkaline earth ions or ammonium ions.

Deetherification process

DOEpatents

Smith, L.A. Jr.

1985-11-05

Ethers such as isobutyl tertiary butyl ether are dissociated into their component alcohols and isoolefins by heat stabilized catalyst compositions prepared from nuclear sulfonic acid, for example, macroporous crosslinked polyvinyl aromatic compounds containing sulfonic acid groups are neutralized with a metal of Al, Fe, Zn, Cu, Ni, ions or mixtures and alkali, alkaline earth metals or ammonium ions by contacting the resin containing the sulfonic acid with aqueous solutions of the metals salts and alkali, alkaline earth metal or ammonium salts. The catalysts have at least 50% of the sulfonic acid groups neutralized with metal ions and the balance of the sulfonic acid groups neutralized with alkali, alkaline earth ions or ammonium ions.

Oxygen-free atomic layer deposition of indium sulfide

DOEpatents

Martinson, Alex B.; Hock, Adam S.; McCarthy, Robert; Weimer, Matthew S.

2016-07-05

A method for synthesizing an In(III) N,N'-diisopropylacetamidinate precursor including cooling a mixture comprised of diisopropylcarbodiimide and diethyl ether to approximately -30.degree. C., adding methyllithium drop-wise into the mixture, allowing the mixture to warm to room temperature, adding indium(III) chloride as a solid to the mixture to produce a white solid, dissolving the white solid in pentane to form a clear and colorless solution, filtering the mixture over a celite plug, and evaporating the solution under reduced pressure to obtain a solid In(III) N,N'-diisopropylacetamidinate precursor. This precursor has been further used to develop a novel atomic layer deposition technique for indium sulfide by dosing a reactor with the precursor, purging with nitrogen, dosing with dilute hydrogen sulfide, purging again with nitrogen, and repeating these steps to increase growth.

Direct Numerical Simulations of Autoignition in Stratified Dimethyl-ether (DME)/Air Turbulent Mixtures

DOE PAGES

Bansal, Gaurav; Mascarenhas, Ajith; Chen, Jacqueline H.

2014-10-01

In our paper, two- and three-dimensional direct numerical simulations (DNS) of autoignition phenomena in stratified dimethyl-ether (DME)/air turbulent mixtures are performed. A reduced DME oxidation mechanism, which was obtained using rigorous mathematical reduction and stiffness removal procedure from a detailed DME mechanism with 55 species, is used in the present DNS. The reduced DME mechanism consists of 30 chemical species. This study investigates the fundamental aspects of turbulence-mixing-autoignition interaction occurring in homogeneous charge compression ignition (HCCI) engine environments. A homogeneous isotropic turbulence spectrum is used to initialize the velocity field in the domain. Moreover, the computational configuration corresponds to amore » constant volume combustion vessel with inert mass source terms added to the governing equations to mimic the pressure rise due to piston motion, as present in practical engines. DME autoignition is found to be a complex three-staged process; each stage corresponds to a distinct chemical kinetic pathway. The distinct role of turbulence and reaction in generating scalar gradients and hence promoting molecular transport processes are investigated. Then, by applying numerical diagnostic techniques, the different heat release modes present in the igniting mixture are identified. In particular, the contribution of homogeneous autoignition, spontaneous ignition front propagation, and premixed deflagration towards the total heat release are quantified.« less

Disruption of oxidative phosphorylation (OXPHOS) by hydroxylated polybrominated diphenyl ethers (OH-PBDEs) present in the marine environment.

PubMed

Legradi, Jessica; Dahlberg, Anna-Karin; Cenijn, Peter; Marsh, Göran; Asplund, Lillemor; Bergman, Åke; Legler, Juliette

2014-12-16

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) are of growing concern, as they have been detected in both humans and wildlife and have been shown to be toxic. Recent studies have indicated that OH-PBDEs can be more toxic than PBDEs, partly due to their ability to disrupt oxidative phosphorylation (OXPHOS), an essential process in energy metabolism. In this study, we determined the OXPHOS disruption potential of 18 OH-PBDE congeners reported in marine wildlife using two in vitro bioassays, namely the classic rat mitochondrial respiration assay, and a mitochondrial membrane potential assay using zebrafish PAC2 cells. Single OH-PBDE congeners as well as mixtures were tested to study potential additive or synergistic effects. An environmental mixture composed of seven OH-PBDE congeners mimicking the concentrations reported in Baltic blue mussels were also studied. We report that all OH-PBDEs tested were able to disrupt OXPHOS via either protonophoric uncoupling and/or inhibition of the electron transport chain. Additionally we show that OH-PBDEs tested in combinations as found in the environment have the potential to disrupt OXPHOS. Importantly, mixtures of OH-PBDEs may show very strong synergistic effects, stressing the importance of further research on the in vivo impacts of these compounds in the environment.

Aqueous solutions of didecyldimethylammonium chloride and octaethylene glycol monododecyl ether: Toward synergistic formulations against enveloped viruses.

PubMed

Nardello-Rataj, Véronique; Leclercq, Loïc

2016-09-10

Micellization of di-n-decyldimethylammonium chloride, [DiC10][Cl], and octaethylene glycol monododecyl ether, C12E8, mixtures have been investigated by surface tension and conductivity measurements. From these results, various physicochemical and thermodynamic key parameters (e.g. micellar mole fraction of [DiC10][Cl], interaction parameter, free energy of micellization, etc.) have been evaluated and discussed in detail. The results prove high synergistic effect between the two surfactants. Based on these results, the virucidal activity of an equimolar mixture of [DiC10][Cl] and C12E8 has been investigated. A marked synergism was observed on lipid-containing deoxyribonucleic and ribonucleic acid viruses, such as herpes virus, respiratory syncytial virus, and vaccinia viruses. In contrast, Coxsackievirus (non-enveloped virus) was not inactivated. These results support that the mechanism is based on the extraction of lipids and/or proteins from the envelope inside the mixed micelles. This extraction creates "holes" the size of which increases with concentration up to a specific value which triggers the virus inactivation. Such a mixture could be used to extend the spectrum of virucidal activity of the amphiphiles virucides commonly employed in numerous disinfectant solutions. Copyright © 2016 Elsevier B.V. All rights reserved.

Molecular Signatures of Methanogens in Cultures and Environmental Samples

NASA Astrophysics Data System (ADS)

Summons, R. E.; Embaye, T.; Jahnke, L. L.; Baumgartner, M.

2002-12-01

The core lipids of methanogens comprise C20 and C40 isoprenoid chains, linked through ether bonds to glycerol. Additional structural diversity is encoded into the polar head groups that are attached to the glycerol ether cores. These compounds are potentially very useful as taxonomic markers in microbial mats and other environmental samples while the nature of the hydrocarbon chains provide a means to identify methanogenic inputs to ancient sediments. The structural diversity of methanogen polar lipids is most valuable when it can be directly correlated to 16S rRNA phylogeny. On the other hand, this diversity can also leads to analytical challenges because there is no single approach that works for all structural types. While some intact methanogen lipids have been identified using mass spectrometry and NMR spectroscopy, the most common means of analysing the lipid cores involves cleavage of the ether bonds using HI and subsequent reduction of the alkyl iodides to hydrocarbons with LiAlH4. One class of methanogenic lipids, the 3?-hydroxyarchaeols, escaped detection for some years because strong acid treatments in the analysis protocols destroyed hydroxyl-containing isoprenoid chains. We have been systematically re-examining the lipids of methanogens, using milder procedures involving weak acid hydrolysis of polar head groups, derivatisation to form trimethylsilyl ethers and analysis by GC-MS. As well as archaeol, sn-2- and sn-3-hydroxyarchaeol, we have tentatively identified a dihydroxyarchaeol in several Methanococcus sp. For Methanococcus thermolithotrophicus an analysis of the total lipid extracts using BBr3 as an ether cleavage reagent followed by LiBEt3H, reduction revealed a very complex mixture consisting of phytane, phytenes, biphytane, biphytenes and a suite of related alcohols. The latter compounds were analysed by GC-MS as their trimethylsilyl ethers and found to comprise a mixture tentatively identified as phytan-N-ol and biphytan-N-ol where N= 3 or 7 or 11 or 15. Apart from phytan-3-ol, these compounds appear to have been overlooked in previous analyses of methanogen lipids. Methanopyrus kandleri, a hyperthermophile that is distinguished from other methanogens by some unusual biochemical features, is also differentiated by having biphytanyl chains with cyclopentane rings. This is a structural feature more commonly found in the Crenarchaeota. We are applying this biomarker methodology to environmental samples in studies of the spatial distribution of methanogenesis relative to other physiologies.

Persulfate Oxidation of MTBE- and Chloroform-Spent Granular Activated Carbon

EPA Science Inventory

Activated persulfate (Na2S2O8) regeneration of methyl tert-butyl ether (MTBE) and chloroform-spent GAC was evaluated in this study. Thermal-activation of persulfate was effective and resulted in greater MTBE removal than either alkaline-activation or H2O2–persulfate binary mixtur...

Evaluation of different solvent mixtures in esterifiable lipids extraction from microalgae Botryococcus braunii for biodiesel production.

PubMed

Hidalgo, Pamela; Ciudad, Gustavo; Navia, Rodrigo

2016-02-01

Non-polar and polar solvents as well as their mixtures were tested for the extraction of microalgae lipids and thus, to evaluate their effect on total and esterifiable lipids extraction yields with potential to be converted to biodiesel. The obtained results show an increase in lipids and esterifiable lipids extraction yields when non-polar and polar solvent mixtures were used. The higher esterifiable lipids extraction yield was 19.2%wt (based on dry biomass) using a chloroform-methanol mixture (75%v/v of methanol), corresponding to a 98.9%wt esterifiable lipids extraction. In addition, esterifiable lipids extraction yield of 18.9%wt (based on dry biomass) was obtained when a petroleum ether-methanol mixture (75%v/v of methanol) was used, corresponding to a 96.9%wt esterifiable lipids extraction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Contact angle and surface tension measurements of a five-ring polyphenyl ether

NASA Technical Reports Server (NTRS)

Jones, W. R., Jr.

1986-01-01

Contact angle measurements were performed for a five-ring polyphenyl ether isomeric mixture on M-50 steel in a dry nitrogen atmosphere. Two different techniques were used: (1) a tilting plate apparatus, and (2) a sessile drop apparatus. Measurements were made for the temperature range 25 to 190 C. Surface tension was measured by a differential maximum bubble pressure technique over the range 23 to 220 C in room air. The critical surface energy of spreading (gamma /sub c/) was determined for the polyphenyl ether by plotting the cosine of the contact angle (theta) versus the surface tension (gamma /sub LV/). The straight line intercept at cosine theta = 1 is defined as gamma (sub c). Gamma (sub c) was found to be 30.1 dyn/cm for the tilting plate technique and 31.3 dyn/cm for the sessile drop technique. These results indicate that the polyphenyl ether is inherently autophobic (i.e., it will not spread on its own surface film until its surface tension is less than gamma /sub c/). This phenomenon is discussed in light of the wettability and wear problems encountered with this fluid.

Contact angle and surface tension measurements of a five-ring polyphenyl ether

NASA Technical Reports Server (NTRS)

Jones, W. R., Jr.

1985-01-01

Contact angle measurements were performed for a five-ring polyphenyl ether isomeric mixture on M-50 steel in a dry nitrogen atmosphere. Two different techniques were used: (1) a tilting plate apparatus, and (2) a sessile drop apparatus. Measurements were made for the temperature range 25 to 190 C. Surface tension was measured by a differential maximum bubble pressure technique over the range 23 to 220C in room air. The critical surface energy of spreading (gamma (sub c)) was determined for the polyphenyl ether by plotting the cosine of the contact angle (theta) versus the surface tension (gamma (sub LV)). The straight line intercept at cosine theta = 1 is defined as gamma (sub c). Gamma (sub c) was found to be 30.1 dyn/cm for the tilting plate technique and 31.3 dyn/cm for the sessile drop technique. These results indicate that the polyphenyl ether is inherently autophobic (i.e., it will not spread on its own surface film until its surface tension is less than gamma (sub c). This phenomenon is discussed in light of the wettability and wear problems encountered with this fluid.

Catalysis and co-catalysis of bond cleavages in coal and coal analogs. Final report, August 1, 1990--January 31, 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, B.

1994-05-01

In work prior to the inception of this project, the authors observed that mixtures of phenolic materials and polyalkoxyaromatic molecules were appreciably more effective in catalyzing the decompositions of di-2-naphthyl ether and of di-1-naphthyl sulfide in tetralin solutions at 450{degrees}C than were the phenols by themselves, even though the polyalkoxyaromatic molecules, in the absence of phenolic co- catalysts, show essentially no catalytic activity. This was of appreciable interest in coal research because dinapthyl ether and dinapthyl sulfide have been employed as model compounds for coals in studies aimed at cleaving ether and sulfide bonds similar to those in coals. Themore » authors proposed (R. K. Sharma, K. P. Raman, and B. Miller) that the mixed catalysts used in these studies catalyze cleavages of ether and sulfide bonds by means of a mechanism involving electron transfer from the polyalkoxyaromatics to the substrates, which are activated as electron acceptors by hydrogen bonding to phenols. Since phenols themselves are electron donors, they also proposed that the well known effects of phenols in catalyzing the conversion of coals are due to similar electron transfer mechanisms.« less

The hydrolysis of geminal ethers: a kinetic appraisal of orthoesters and ketals.

PubMed

Repetto, Sonia L; Costello, James F; Butts, Craig P; Lam, Joseph K W; Ratcliffe, Norman M

2016-01-01

A novel approach to protecting jet fuel against the effects of water contamination is predicated upon the coupling of the rapid hydrolysis reactions of lipophilic cyclic geminal ethers, with the concomitant production of a hydrophilic acyclic hydroxyester with de-icing properties (Fuel Dehydrating Icing Inhibitors - FDII). To this end, a kinetic appraisal of the hydrolysis reactions of representative geminal ethers was undertaken using a convenient surrogate for the fuel-water interface (D2O/CD3CN 1:4). We present here a library of acyclic and five/six-membered cyclic geminal ethers arranged according to their hydroxonium catalytic coefficients for hydrolysis, providing for the first time a framework for the development of FDII. A combination of (1)H NMR, labelling and computational studies was used to assess the effects that may govern the observed relative rates of hydrolyses.

A New Synthesis of Tertiary Alkyl N-Arylcarbamates from Isocyanates.

ERIC Educational Resources Information Center

Bailey, William J.; Griffith, James R.

1978-01-01

The method involves the dissolution of a small piece of metallic lithium in a small quantity of tertiary alcohol followed by addition to a mixture of the isocyanate and the tertiary alcohol in ether. This should be useful in organic chemistry laboratory courses for the identification of tertiary alcohols. (Author/BB)

Process for synthesis of beryllium chloride dietherate

DOEpatents

Bergeron, Charles; Bullard, John E.; Morgan, Evan

1991-01-01

A low temperature method of producing beryllium chloride dietherate through the addition of hydrogen chloride gas to a mixture of beryllium metal in ether in a reaction vessel is described. A reflux condenser provides an exit for hydrogen produced form the reaction. A distillation condenser later replaces the reflux condenser for purifying the resultant product.

A SHORT-TERM DOSING MODEL FOR DETECTING THE EFFECTS OF ENVIRONMENTAL CONTAMINANTS ON THYROID HORMONES IN THE RAT: EFFECTS OF PESTICIDES.

EPA Science Inventory

Recently, a short-term rat dosing model has been developed to examine the effects of environmental mixtures on thyroid homeostasis (TH). Prototypic chemicals such as dioxins, polychlorinated biphenyls and polybrominated diphenyl ethers have been tested and shown to adversely impa...

Triacylglycerol estolides, a new class of mammalian lipids, in the paracloacal gland of the brushtail possum (Trichosurus vulpecula).

PubMed

McLean, Stuart; Davies, Noel W; Nichols, David S; Mcleod, Bernie J

2015-06-01

The paracloacal glands are the most prevalent scent glands in marsupials, and previous investigation of their secretions in the brushtail possum (Trichosurus vulpecula) has identified many odorous compounds together with large amounts of neutral lipids. We have examined the lipids by LC-MS, generating ammonium adducts of acylglycerols by electrospray ionisation. Chromatograms showed a complex mixture of coeluting acylglycerols, with m/z from about 404 to 1048. Plots of single [M + NH4](+) ions showed three groups of lipids clearly separated by retention time. MS-MS enabled triacylglycerols and diacylglycerol ethers to be identified from neutral losses and formation of diacylglycerols and other product ions. The earliest-eluting lipids were found to be triacylglycerol estolides, in which a fourth fatty acid forms an ester link with a hydroxy fatty acid attached to the glycerol chain. This is the first report of triacylglycerol estolides in animals. They form a complex mixture with the triacylglycerols and diacylglycerol ethers of lipids with short- and long-chain fatty acids with varying degrees of unsaturation. This complexity suggests a functional role, possibly in social communication.

Phase equilibrium measurements on twelve binary mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giles, N.F.; Wilson, H.L.; Wilding, W.V.

1996-11-01

Phase equilibrium measurements have been performed on twelve binary mixtures. The PTx method was used to obtain vapor-liquid equilibrium data for the following binary systems at two temperatures each: ethanethiol + propylene; nitrobenzene + methanol; pyridine + ethyl acetate; octane + tert-amyl methyl ether; diisopropyl ether + butane; 1,3-dichloro-2-propanol + epichlorohydrin; 2,3-dichloro-1-propanol + epichlorohydrin; 2,3-epoxy-1-propanol + epichlorohydrin; 3-chloro-1,2-propanediol + epichlorohydrin; methanol + hydrogen cyanide. For these systems, equilibrium vapor and liquid phase compositions were derived from the PTx data using the Soave equation of state to represent the vapor phase and the Wilson, NRTL, or Redlich-Kister activity coefficient model tomore » represent the liquid phase. The infinite dilution activity coefficient of methylamine in N-methyl-2-pyrrolidone was determined at three temperatures by performing PTx measurements on the N-methyl-2-pyrrolidone was determined at three temperatures by performing PTx measurements on the N-methyl-2-pyrrolidone-rich half of the binary. Liquid-liquid equilibrium studies were made on the triethylene glycol + 1-pentene system at two temperatures by directly analyzing samples taken from each liquid phase.« less

Fabrication of Free-Standing, Self-Aligned, High-Aspect-Ratio Synthetic Ommatidia.

PubMed

Jun, Brian M; Serra, Francesca; Xia, Yu; Kang, Hong Suk; Yang, Shu

2016-11-16

Free-standing, self-aligned, high-aspect-ratio (length to cross-section, up to 15.5) waveguides that mimic insects' ommatidia are fabricated. Self-aligned waveguides under the lenses are created after exposing photoresist SU-8 film through the negative polydimethylsiloxane (PDMS) lens array. Instead of drying from the developer, the waveguides are coated with poly(vinyl alcohol) and then immersed into a mixture of PDMS precursor and diethyl ether. The slow drying of diethyl ether, followed by curing and peeling off PDMS, allows for the fabrication of free-standing waveguides without collapse. We show that the synthetic ommatidia can confine light and propagate it all the way to the tips.

Semi-Microscale Williamson Ether Synthesis and Simultaneous Isolation of an Expectorant from Cough Tablets

NASA Astrophysics Data System (ADS)

Stabile, Ryan G.; Dicks, Andrew P.

2003-03-01

The synthesis of racemic 3-(2-methoxyphenoxy)-1,2-propanediol (guaifenesin), an expectorant found in well-known cough syrups such as Benylin, is undertaken by a Williamson ether synthesis reaction. The same compound is simultaneously isolated and characterized from commercially available Guai-Aid cough tablets. The experiment is well-suited towards the introductory part of an advanced organic laboratory course and complements typical lecture topics in a stimulating manner. Consideration is given towards reaction mechanisms, stereochemistry, optical activity, pharmaceutical synthesis, and spectroscopic analysis. Discussion of the merits or disadvantages of marketing a drug as a racemic mixture, with reference to the notorious thalidomide case study, and the concept of enantioselective synthesis is possible.

A Short, One-Pot Synthesis of Bupropion (Zyban®, Wellbutrin®)

NASA Astrophysics Data System (ADS)

Perrine, Daniel M.; Ross, Jason T.; Nervi, Stephen J.; Zimmerman, Richard H.

2000-11-01

A one-pot synthesis of (±)-2-(t-butylamino)-3'-chloropropiophenone (bupropion) as its hydrochloride salt (Zyban, Wellbutrin), an important antidepressant drug used in the treatment of nicotine addiction, is described. The procedure, suitable for students in their first year of organic chemistry, can be carried out in less than two hours and provides material of high purity in overall yield of 75-85%. A solution of m-chloropropiophenone in CH2Cl2 is treated with Br2. After removal of the solvent, t-butylamine and N-methylpyrrolidinone are added and the mixture is warmed briefly, quenched with water, and extracted with ether. Concentrated HCl is added to the ether solution to precipitate the product.

Rotational Investigation of the Adducts of Formic Acid with Alcohols, Ethers and Esters

NASA Astrophysics Data System (ADS)

Evangelisti, Luca; Spada, Lorenzo; Li, Weixing; Caminati, Walther

2016-06-01

Mixtures of formic acid with methyl alcohol, with isopropyl alcohol, with tert-butyl alcohol, with dimethylether and with isopropylformiate have been supersonically expanded as pulsed jets. The obtained cool plumes have been analyzed by Fourier transform microwave spectroscopy. It has been possible to assign the rotational spectra of the 1:1 adducts of formic acid with tert-butyl alcohol, with dimethyl ether and with isopropylformiate. The conformational shapes and geometries of these adducts, as well as the topologies of their itermolecular hydrogen bonds will be presented. An explanation is given of the failure of the assignments of the rotational spectra of the adducts of formic acid with methyl alcohol and isopropyl alcohol.

A Human Mixture Risk Assessment for Neurodevelopmental Toxicity Associated with Polybrominated Diphenyl Ethers Used as Flame Retardants

PubMed Central

Martin, Olwenn V.; Evans, Richard M.; Faust, Michael

2017-01-01

Background: The European Food Safety Authority recently concluded that the exposure of small children (1–3 y old) to brominated diphenyl ether (BDE)-99 may exceed acceptable levels defined in relation to neurodevelopmental toxicity in rodents. The flame retardant BDE-209 may release BDE-99 and other lower brominated BDEs through biotic and abiotic degradation, and all age groups are exposed not only to BDE-209 and -99 but also to a cocktail of BDE congeners with evidence of neurodevelopmental toxicity. The possible risks from combined exposures to these substances have not been evaluated. Objectives: We performed a congener-specific mixture risk assessment (MRA) of human exposure to combinations of BDE-209 and other BDEs based on estimated exposures via diet and dust intake and on measured levels in biologic samples. Methods: We employed the Hazard Index (HI) method by using BDE congener-specific reference doses for neurodevelopmental toxicity. Results: Our HI analysis suggests that combined exposures to polybrominated diphenyl ethers (PBDEs) may exceed acceptable levels in breastfeeding infants (0–3 mo old) and in small children (1–3 y old), even for moderate (vs. high) exposure scenarios. Our estimates also suggest that acceptable levels of combined PBDEs may be exceeded in adults whose diets are high in fish. Small children had the highest combined exposures, with some estimated body burdens that were similar to body burdens associated with developmental neurotoxicity in rodents. Conclusions: Our estimates corroborate reports from several recent epidemiological studies of associations between PBDE exposures and neurobehavioral outcomes, and they support the inclusion of BDE-209 in the persistent organic pollutant (POP) convention as well as the need for strategies to reduce exposures to PBDE mixtures, including maximum residue limits for PBDEs in food and measures for limiting the release of PBDEs from consumer waste. https://doi.org/10.1289/EHP826 PMID:28886598

Passive air sampling of polybrominated diphenyl ethers in New Delhi, Kolkata, Mumbai and Chennai: Levels, homologous profiling and source apportionment.

PubMed

Chakraborty, Paromita; Zhang, Gan; Cheng, Hairong; Balasubramanian, Prithiviraj; Li, Jun; Jones, Kevin C

2017-12-01

Several studies in the recent past reported new sources for industrial persistent organic pollutants (POPs) from metropolitan cities of India. To fill the data gap for atmospheric polybrominated diphenyl ethers (PBDEs), polyurethane foam disk passive air sampling (PUF-PAS) was conducted along urban-suburban-rural transects in four quadrilateral cities viz., New Delhi, Kolkata, Mumbai and Chennai from northern, eastern, western and southern India respectively. Average concentration of Σ 8 PBDEs in pg/m 3 for New Delhi, Kolkata, Mumbai and Chennai were 198, 135, 264 and 144 respectively. We observed a distinct urban > suburban > rural trend for atmospheric PBDEs in Mumbai. Principal component analysis (PCA) attributed three different source types. BDE-47, -99, -100, -153 and -154 loaded in the first component were relatively high in the sites where industrial and informal electronic waste (e-waste) recycling activities were prevalent. Penta congener, BDE-99 and tetra congener, BDE-47 contributed 50%-75% of total PBDEs. Ratio of BDE-47 and -99 in Indian cities reflected the usage of penta formulations like Bromkal -70DE and DE-71 in the commercial and electrical products. PC-2 was loaded with BDE-28 and -35. Percentage of BDE-28 and BDE-35 (>10%) were comparatively much higher than commercial penta products. Abundance of BDE-28 in majority sites can be primarily due to re-emission from surface soil. PC-3 was loaded with BDE-183 and elevated levels were observed mostly in the industrial corridor of Indian cities. BDE-183 was notably high in the urban industrial sites of New Delhi. We suspect this octa-BDE congener resulted from recycling process of plastic products containing octa-BDE formulation used as flame retardants. Copyright © 2017 Elsevier Ltd. All rights reserved.

The hydrolysis of geminal ethers: a kinetic appraisal of orthoesters and ketals

PubMed Central

Repetto, Sonia L; Butts, Craig P; Lam, Joseph K W; Ratcliffe, Norman M

2016-01-01

Summary A novel approach to protecting jet fuel against the effects of water contamination is predicated upon the coupling of the rapid hydrolysis reactions of lipophilic cyclic geminal ethers, with the concomitant production of a hydrophilic acyclic hydroxyester with de-icing properties (Fuel Dehydrating Icing Inhibitors - FDII). To this end, a kinetic appraisal of the hydrolysis reactions of representative geminal ethers was undertaken using a convenient surrogate for the fuel–water interface (D2O/CD3CN 1:4). We present here a library of acyclic and five/six-membered cyclic geminal ethers arranged according to their hydroxonium catalytic coefficients for hydrolysis, providing for the first time a framework for the development of FDII. A combination of 1H NMR, labelling and computational studies was used to assess the effects that may govern the observed relative rates of hydrolyses. PMID:27559399

Regioselective desymmetrization of diaryltetrahydrofurans via directed ortho-lithiation: an unexpected help from green chemistry.

PubMed

Mallardo, Valentina; Rizzi, Ruggiero; Sassone, Francesca C; Mansueto, Rosmara; Perna, Filippo M; Salomone, Antonio; Capriati, Vito

2014-08-14

An efficient functionalization of diaryltetrahydrofurans via a regioselective THF-directed ortho-lithiation is first described. This reaction can be successfully carried out in cyclopentyl methyl ether as a "greener" alternative to Et2O, with better results in terms of yield and selectivity and, surprisingly, also in protic eutectic mixtures competitively with protonolysis.

Solvent effects on the polar network of ionic liquid solutions

NASA Astrophysics Data System (ADS)

Bernardes, Carlos E. S.; Shimizu, Karina; Canongia Lopes, José N.

2015-05-01

Molecular dynamics simulations were used to probe mixtures of ionic liquids (ILs) with common molecular solvents. Four types of systems were considered: (i) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide plus benzene, hexafluorobenzene or 1,2-difluorobenzene mixtures; (ii) choline-based ILs plus ether mixtures (iii) choline-based ILs plus n-alkanol mixtures; and (iv) 1-butyl-3-methylimidazolium nitrate and 1-ethyl-3-methylimidazolium ethyl sulfate aqueous mixtures. The results produced a wealth of structural and aggregation information that highlight the resilience of the polar network of the ILs (formed by clusters of alternating ions and counter-ions) to the addition of different types of molecular solvent. The analysis of the MD data also shows that the intricate balance between different types of interaction (electrostatic, van der Waals, H-bond-like) between the different species present in the mixtures has a profound effect on the morphology of the mixtures at a mesoscopic scale. In the case of the IL aqueous solutions, the present results suggest an alternative interpretation for very recently published x-ray and neutron diffraction data on similar systems.

Isolation and Identification of Active Compounds from Papaya Plants and Activities as Antimicrobial

NASA Astrophysics Data System (ADS)

Prasetya, A. T.; Mursiti, S.; Maryan, S.; Jati, N. K.

2018-04-01

Extraction and isolation of papaya seeds and leaves (Carica papaya L) has been performed using n-hexane and ethanol solvents. Further isolation of the extract obtained using ethyl acetate and diethyl ether solvents. The result of the phytochemical test of papaya extract obtained by mixture of an active compound of flavonoids, alkaloids, tannins, steroids, and saponins. Ethyl acetate isolates containing only flavonoids and diethyl ether isolates contain only alkaloids. Extracts and isolates from papaya plants had gram-positive antibacterial activity greater than the gram-negative bacteria, but both did not have antifungal activity. Papaya extracts have greater antibacterial activity than flavonoid isolates and alkaloid isolates. Strong antibacterial inhibitory sequences are extracts of papaya plants, flavonoid isolates, and alkaloid isolates.

Measurements of Flat-Flame Velocities of Diethyl Ether in Air

PubMed Central

Gillespie, Fiona; Metcalfe, Wayne K.; Dirrenberger, Patricia; Herbinet, Olivier; Glaude, Pierre-Alexandre; Battin-Leclerc, Frédérique; Curran, Henry J.

2013-01-01

This study presents new adiabatic laminar burning velocities of diethyl ether in air, measured on a flat-flame burner using the heat flux method. The experimental pressure was 1 atm and temperatures of the fresh gas mixture ranged from 298 to 398 K. Flame velocities were recorded at equivalence ratios from 0.55 to 1.60, for which stabilization of the flame was possible. The maximum laminar burning velocity was found at an equivalence ratio of 1.10 or 1.15 at different temperatures. These results are compared with experimental and computational data reported in the literature. The data reported in this study deviate significantly from previous experimental results and are well-predicted by a previously reported chemical kinetic mechanism. PMID:23710107

Low-temperature radiation copolymerization of tetrafluoroethylene with perfluorovinyl ethers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, I.P.; Pirozhnaya, L.N.; Loginova, N.N.

1986-12-01

The copolymerization of perfluorovinyl ethers with tetrafluoroethylene at low temperature was studied and compared with the process conducted with chemical initiation in bulk or aqueous medium. A calorimetric method was used for studying the kinetics of copolymerization, the phase state of the system, and the phase transition dynamics. Ampules containing the samples of monomers and mixtures were irradiated at 77/sup 0/K with /sup 60/Co ..gamma.. rays with a dose rate of 25 kGy/h. Radiolysis in the solid phase at 77/sup 0/K with a 130 kGy dose resulted in the formation of 0.5-1.0 wt.% of a polymer, and this polymer wasmore » soluble in the monomer.« less

Synthesis of Improved Antileishmanial and Antitrypanosomal Drugs Treatment and Prophylaxis

DTIC Science & Technology

1986-11-01

for a diphenyl ether analog ((2) p. 44). 16 - -r , ü$$m&±ysc$c .<v£*^Ä VV’-Orfs aB9*>ratfe>^v CHART NO. 1 8-[(6-AMIDOXIMINOHEXYL)AMINO]-6-METHOXY...MALEATE (SNL-130) cico—(f)V-ci A1C1 CS 1 (58%) • Brü 1) »3PCH2CH2NMe2/n-BuLi 2) H30* 3) Oxalic Acid 4) OH 0 «CHCH,NMe 2ŕ,c2 2 (79%), Free base... diphenyl ether analog ((2) p. 44). A mixture of sodium amide (11.6 g, O.J mol), acetonitrile (15 mL, 11.8 g> 0.29 mol) and dry benzene (1 L) was heated

Methyl-perfluoroheptene-ethers (CH3OC7F13): measured OH radical reaction rate coefficients for several isomers and enantiomers and their atmospheric lifetimes and global warming potentials.

PubMed

Jubb, Aaron M; Gierczak, Tomasz; Baasandorj, Munkhbayar; Waterland, Robert L; Burkholder, James B

2014-05-06

Mixtures of methyl-perfluoroheptene-ethers (CH3OC7F13, MPHEs) are currently in use as replacements for perfluorinated alkanes (PFCs) and poly-ether heat transfer fluids, which are persistent greenhouse gases with lifetimes >1000 years. At present, the atmospheric processing and environmental impact from the use of MPHEs is unknown. In this work, rate coefficients at 296 K for the gas-phase reaction of the OH radical with six key isomers (including stereoisomers and enantiomers) of MPHEs used commercially were measured using a relative rate method. Rate coefficients for the six MPHE isomers ranged from ∼ 0.1 to 2.9 × 10(-12) cm(3) molecule(-1) s(-1) with a strong stereoisomer and -OCH3 group position dependence; the (E)-stereoisomers with the -OCH3 group in an α- position relative to the double bond had the greatest reactivity. Rate coefficients measured for the d3-MPHE isomer analogues showed decreased reactivity consistent with a minor contribution of H atom abstraction from the -OCH3 group to the overall reactivity. Estimated atmospheric lifetimes for the MPHE isomers range from days to months. Atmospheric lifetimes, radiative efficiencies, and global warming potentials for these short-lived MPHE isomers were estimated based on the measured OH rate coefficients along with measured and theoretically calculated MPHE infrared absorption spectra. Our results highlight the importance of quantifying the atmospheric impact of individual components in an isomeric mixture.

Headspace Solid-Phase Microextraction and Ultrasonic Extraction with the Solvent Sequences in Chemical Profiling of Allium ursinum L. Honey.

PubMed

Jerković, Igor; Kuś, Piotr M

2017-11-06

A volatile profile of ramson (wild garlic, Allium ursinum L.) honey was investigated by headspace solid-phase microextraction (HS-SPME) and ultrasonic solvent extraction (USE) followed by gas chromatography and mass spectrometry (GC-FID/GC-MS) analyses. The headspace was dominated by linalool derivatives: cis - and trans -linalool oxides (25.3%; 9.2%), hotrienol (12.7%), and linalool (5.8%). Besides direct extraction with dichloromethane and pentane/diethyl ether mixture (1:2, v / v ), two solvent sequences (I: pentane → diethyl ether; II: pentane → pentane/diethyl ether (1:2, v / v ) → dichloromethane) were applied. Striking differences were noted among the obtained chemical profiles. The extracts with diethyl ether contained hydroquinone (25.8-36.8%) and 4-hydroxybenzoic acid (11.6-16.6%) as the major compounds, while ( E )-4-(r-1',t-2',c-4'-trihydroxy-2',6',6'-trimethylcyclohexyl)but-3-en-2-one predominated in dichloromethane extracts (18.3-49.1%). Therefore, combination of different solvents was crucial for the comprehensive investigation of volatile organic compounds in this honey type. This particular magastigmane was previously reported only in thymus honey and hydroquinone in vipers bugloss honey, while a combination of the mentioned predominant compounds is unique for A. ursinum honey.

Uptake of polybrominated diphenyl ethers by carrot and lettuce crops grown in compost-amended soils.

PubMed

Bizkarguenaga, E; Iparraguirre, A; Oliva, E; Quintana, J B; Rodil, R; Fernández, L A; Zuloaga, O; Prieto, A

2016-02-01

The uptake of polybrominated diphenyl ethers (PBDEs) by carrot and lettuce was investigated. Degradation of PBDEs in soil in the absence of the plants was discarded. Different carrot (Nantesa and Chantenay) and lettuce (Batavia Golden Spring and Summer Queen) varieties were grown in fortified or contaminated compost-amended soil mixtures under greenhouse conditions. After plant harvesting, roots (core and peel) and leaves were analyzed separately for carrot, while for lettuce, leaves and hearts were analyzed together. The corresponding bioconcentration factors (BCFs) were calculated. In carrots, a concentration gradient of 2,2',3,4,4',5'-hexabromodiphenyl ether (BDE-138) became evident that decreased from the root peel via root core to the leaves. For decabromodiphenyl ether (BDE-209) at the low concentration level (7 and 20 ng g(-1)), the leaves incorporated the highest concentration of the target substance. For lettuce, a decrease in the BCF value (from 0.24 to 0.02) was observed the higher the octanol-water partition coefficient, except in the case of BDE-183 (BCF = 0.51) and BDE-209 (BCF values from 0.41 to 0.74). Significant influence of the soils and crop varieties on the uptake could not be supported. Metabolic debromination, hydroxylation or methylation of the target PBDEs in the soil-plant system was not observed.

Preparation of reminiscent aroma mixture of Japanese soy sauce.

PubMed

Bonkohara, Kaori; Fuji, Maiko; Nakao, Akito; Igura, Noriyuki; Shimoda, Mitsuya

2016-01-01

To prepare an aroma mixture of Japanese soy sauce by fewest components, the aroma concentrate of good sensory attributes was prepared by polyethylene membrane extraction, which could extract only the volatiles with diethyl ether. GC-MS-Olfactometry was done with the aroma concentrate, and 28 odor-active compounds were detected. Application of aroma extract dilution analysis to the separated fraction revealed high flavor dilution factors with respect to acetic acid, 4-hydroxy-2(or5)-ethyl-5(or2)-methyl-3(2H)-furanone (HEMF), 3-methyl-1-butanol (isoamyl alcohol), and 3-(methylsulfanyl)propanal (methional). A model aroma mixture containing above four odorants showed a good similarity with the aroma of the soy sauce itself. Consequently, the reminiscent aroma mixture of soy sauce was prepared in water. The ratio of acetic acid, HEMF, isoamyl alcohol, and methional was 2500:300:100:1.

Renewable Gasoline, Solvents, and Fuel Additives from 2,3-Butanediol.

PubMed

Harvey, Benjamin G; Merriman, Walter W; Quintana, Roxanne L

2016-07-21

2,3-Butanediol (2,3-BD) is a renewable alcohol that can be prepared in high yield from biomass sugars. 2,3-BD was selectively dehydrated in a solvent-free process to a complex mixture of 2-ethyl-2,4,5-trimethyl-1,3-dioxolanes and 4,5-dimethyl-2isopropyl dioxolanes with the heterogeneous acid catalyst Amberlyst-15. The purified dioxolane mixture exhibited an anti-knock index of 90.5, comparable to high octane gasoline, and a volumetric net heat of combustion 34 % higher than ethanol. The solubility of the dioxolane mixture in water was only 0.8 g per 100 mL, nearly an order of magnitude lower than the common gasoline oxygenate methyl tert-butyl ether. The dioxolane mixture has potential applications as a sustainable gasoline blending component, diesel oxygenate, and industrial solvent. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecular dynamics simulations of polyethers and a quaternary ammonium ionic liquid as CO2 absorbers

NASA Astrophysics Data System (ADS)

Cardoso, Piercarlo Fortunato; Fernandez, Juan S. L. C.; Lepre, Luiz Fernando; Ando, Rômulo Augusto; Costa Gomes, Margarida F.; Siqueira, Leonardo J. A.

2018-04-01

The properties of mixtures of butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, [N4111][NTf2], with poly(ethyleneglycol) dimethyl ether, PEO, were described as a function of PEO chain size by molecular dynamics simulations. Both PEO chain size and mixture composition revealed to play a significant role in determining the structure and the dynamics of the fluids. The remarkably higher viscosity observed for mixtures composed by 0.25 mole fraction of PEO was attributed to the increase in the gauche population of OCCO dihedral of the polyether of longer chains. The negative solvation enthalpy (ΔsolH < 0) and entropy (ΔsolS < 0) revealed a favorable CO2 absorption by the neat and mixture systems. The CO2 absorption was higher in neat PEO, particularly considering longer chains. The gas solubility in the mixtures presented intermediate values in comparison to the neat PEO and neat ionic liquid. The CO2 solutions had their structures discussed in the light of the calculated radial and spatial distribution functions.

Molecular dynamics simulations of polyethers and a quaternary ammonium ionic liquid as CO2 absorbers.

PubMed

Cardoso, Piercarlo Fortunato; Fernandez, Juan S L C; Lepre, Luiz Fernando; Ando, Rômulo Augusto; Costa Gomes, Margarida F; Siqueira, Leonardo J A

2018-04-07

The properties of mixtures of butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, [N 4111 ][NTf 2 ], with poly(ethyleneglycol) dimethyl ether, PEO, were described as a function of PEO chain size by molecular dynamics simulations. Both PEO chain size and mixture composition revealed to play a significant role in determining the structure and the dynamics of the fluids. The remarkably higher viscosity observed for mixtures composed by 0.25 mole fraction of PEO was attributed to the increase in the gauche population of OCCO dihedral of the polyether of longer chains. The negative solvation enthalpy (Δ sol H < 0) and entropy (Δ sol S < 0) revealed a favorable CO 2 absorption by the neat and mixture systems. The CO 2 absorption was higher in neat PEO, particularly considering longer chains. The gas solubility in the mixtures presented intermediate values in comparison to the neat PEO and neat ionic liquid. The CO 2 solutions had their structures discussed in the light of the calculated radial and spatial distribution functions.

Synergism and Physicochemical Properties of Anionic/Amphoteric Surfactant Mixtures with Nonionic Surfactant of Amine Oxide Type

NASA Astrophysics Data System (ADS)

Blagojević, S. M.; Pejić, N. D.; Blagojević, S. N.

2017-12-01

The physicochemical properties of initial formulation, that is anionic/amphoteric surfactants mixture SLES/AOS/CAB (sodium lauryl ether sulfate (SLES), α-olefin sulfonates (AOS) and cocamidopropyl betaine (CAB) at ratio 80 : 15 : 5) with nonionic surfactant of amine oxide type (lauramine oxide (AO)) in various concentration (1-5%) were studied. To characterize the surfactants mixture, the critical micelle concentration (CMC), surface tension (γ), foam volume, biodegradability and irritability were determined. This study showed that adding of AO in those mixtures lowered both γ and CMC as well as enhanced SLES/AOS/CAB foaming properties, but did not significantly affect biodegradability and irritability of initial formulation. Moreover, an increase in AO concentration has a meaningful synergistic effect on the initial formulation properties. All those results indicates that a nonionic surfactant of amine oxide type significantly improves the performance of anionic/amphoteric mixed micelle systems, and because of that anionic/amphoteric/nonionic mixture can be used in considerably lower concentrations as a cleaning formulation.

Novel Chromatographic Methods for Simultaneous Quantification of Fish and Wheat Germ Oils Mixture in Pharmaceutical Dosage Forms.

PubMed

El-Yazbi, Amira F; El-Hawiet, Amr

2017-05-01

Two simple, direct and environment-friendly chromatographic methods, high-performance liquid chromatography (HPLC) and high-performance thin layer chromatographic (HPTLC), were developed for the determination of a binary mixture of fish oil (FO) and wheat germ oil (WGO), for the first time, in their pharmaceutical dosage forms with no need for any sample pretreatment. The HPLC separation was carried out using C-18 stationary phase with mobile phase of 15% formic acid (pH 6), methanol and acetonitrile through gradient-elution, 1.5 mL min-1 flow-rate and detection at 215 nm for FO and 280 nm for WGO. HPTLC separation was carried out on silica-coated plates using diethyl ether-petroleum ether (0.5:9.5, v/v) as mobile phase. Detection was at 215 nm for FO and 240 nm for WGO. Regression analysis showed good linear relationship with r > 0.999 in the concentration-ranges of 0.2-2 mg mL-1 and 2.5-20 μg band-1 for WGO by HPLC and HPTLC methods, respectively, and 0.4-10 mg mL-1 and 25-200 μg band-1 for FO by HPLC and HPTLC methods, respectively. The methods were validated, showed good analytical performance and were successfully applied for the analysis of pharmaceutical formulations and synthetic mixtures of the analytes with good recoveries. Therefore, the two methods could be conveniently adopted for routine analysis of similar products in quality control laboratories of pharmaceutical industries especially that simultaneous determination of FO-WGO mixture has not been reported previously. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

New evidences in the complexity of contamination of the lagoon of Venice: polybrominated diphenyl ethers (PBDEs) pollution.

PubMed

Parolini, Marco; Binelli, Andrea; Marin, Maria Gabriella; Matozzo, Valerio; Masiero, Luciano; Provini, Alfredo

2012-04-01

This study presents the first evaluation of the current pollution by polybrominated diphenyl ethers (PBDEs) of surface sediments from the Lagoon of Venice. We focused the research on tri-to hepta-BDEs, the main components of penta- and octa-mixtures, which are considered to be the most toxic for the biocoenosis. The results pointed out a quite homogeneous contamination of this keystone European transitional environment, with ∑ (13)PBDEs values ranging from 0.39 to 6.78 ng/g dry weight; these values reflect low to moderate pollution levels, which is in conformity to other coastal European ecosystems. The average PBDE profile of the lagoon sediments follows this decreasing trend of congeners: BDE-47>BDE-99> >BDE-190>BDE-28>BDE-153>BDE-154>BDE-138, BDE-183, and BDE-17, which is similar to the worldwide distribution pattern. BDE-47 and BDE-99 revealed a recent use of a penta-BDE mixture, while the presence of hepta-BDEs (BDE-183 and BDE-190) in all of the sites can indicate the actual use of a deca-BDE formulation, because these congeners are considered to be debrominated byproducts of BDE-209 degradation.

An international survey of decabromodiphenyl ethane (deBDethane) and decabromodiphenyl ether (decaBDE) in sewage sludge samples.

PubMed

Ricklund, Niklas; Kierkegaard, Amelie; McLachlan, Michael S

2008-12-01

Decabromodiphenyl ethane (deBDethane) is an additive flame retardant marketed as a replacement for decabromodiphenyl ether (decaBDE). The structures of the two chemicals are similar, and hence deBDethane may also become an environmental contaminant of concern. Environmental data on deBDethane are scarce. Since sewage sludge is an early indicator of leakage of these chemicals into the environment, an international survey of deBDethane and decaBDE levels in sludge was conducted. Samples were collected from 42 WWTPs in 12 different countries and analyzed with GC/LRMS. DeBDethane was present in sludge from all countries and may therefore be a worldwide concern. The levels of deBDethane in sludge samples from the Ruhr area of Germany were the highest so far reported in the literature (216 ng g(-1)d.wt.). The [deBDethane]/[decaBDE] quotient for the whole data set ranged from 0.0018 to 0.83. High ratios were found in and around Germany where deBDethane imports are known to have been high and substitution of decaBDE with deBDethane is likely to have occurred. Low ratios were found in the USA and the UK, countries that have traditionally been large users of decaBDE. An estimate of the flux of deBDEthane from the technosphere via WWTPs to the environment within the European Union gave 1.7+/-0.34 mg annually per person. The corresponding value for decaBDE was 41+/-22 mg annually per person.

Self-ignition of S.I. engine model fuels: A shock tube investigation at high pressure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fieweger, K.; Blumenthal, R.; Adomeit, G.

1997-06-01

The self-ignition of several spark-ignition (SI) engine fuels (iso-octane, methanol, methyl tert-butyl ether and three different mixtures of iso-octane and n-heptane), mixed with air, was investigated experimentally under relevant engine conditions by the shock tube technique. Typical modes of the self-ignition process were registered cinematographically. For temperatures relevant to piston engine combustion, the self-ignition process always starts as an inhomogeneous, deflagrative mild ignition. This instant is defined by the ignition delay time, {tau}{sub defl}. The deflagration process in most cases is followed by a secondary explosion (DDT). This transition defines a second ignition delay time, {tau}{sub DDT}, which is amore » suitable approximation for the chemical ignition delay time, if the change of the thermodynamic conditions of the unburned test gas due to deflagration is taken into account. For iso-octane at p = 40 bar, a NTC (negative temperature coefficient), behavior connected with a two step (cool flame) self-ignition at low temperatures was observed. This process was very pronounced for rich and less pronounced for stoichiometric mixtures. The results of the {tau}{sub DDT} delays of the stoichiometric mixtures were shortened by the primary deflagration process in the temperature range between 800 and 1,000 K. Various mixtures of iso-octane and n-heptane were investigated. The results show a strong influence of the n-heptane fraction in the mixture, both on the ignition delay time and on the mode of self-ignition. The self-ignition of methanol and MTBE (methyl tert-butyl ether) is characterized by a very pronounced initial deflagration. For temperatures below 900 K (methanol: 800 K), no secondary explosion occurs. Taking into account the pressure increase due to deflagration, the measured delays {tau}{sub DDT} of the secondary explosion are shortened by up to one order of magnitude.« less

Applications of the Simple Multi-Fluid Model to Correlations of the Vapor-Liquid Equilibrium of Refrigerant Mixtures Containing Carbon Dioxide

NASA Astrophysics Data System (ADS)

Akasaka, Ryo

This study presents a simple multi-fluid model for Helmholtz energy equations of state. The model contains only three parameters, whereas rigorous multi-fluid models developed for several industrially important mixtures usually have more than 10 parameters and coefficients. Therefore, the model can be applied to mixtures where experimental data is limited. Vapor-liquid equilibrium (VLE) of the following seven mixtures have been successfully correlated with the model: CO2 + difluoromethane (R-32), CO2 + trifluoromethane (R-23), CO2 + fluoromethane (R-41), CO2 + 1,1,1,2- tetrafluoroethane (R-134a), CO2 + pentafluoroethane (R-125), CO2 + 1,1-difluoroethane (R-152a), and CO2 + dimethyl ether (DME). The best currently available equations of state for the pure refrigerants were used for the correlations. For all mixtures, average deviations in calculated bubble-point pressures from experimental values are within 2%. The simple multi-fluid model will be helpful for design and simulations of heat pumps and refrigeration systems using the mixtures as working fluid.

Effect of benzene and ethylbenzene on the transcription of methyl-tert-butyl ether degradation genes of Methylibium petroleiphilum PM1.

PubMed

Joshi, Geetika; Schmidt, Radomir; Scow, Kate M; Denison, Michael S; Hristova, Krassimira R

2016-09-01

Methyl-tert-butyl ether (MTBE) and its degradation by-product, tert-butyl alcohol (TBA), are widespread contaminants detected frequently in groundwater in California. Since MTBE was used as a fuel oxygenate for almost two decades, leaking underground fuel storage tanks are an important source of contamination. Gasoline components such as BTEX (benzene, toluene, ethylbenzene and xylenes) are often present in mixtures with MTBE and TBA. Investigations of interactions between BTEX and MTBE degradation have not yielded consistent trends, and the molecular mechanisms of BTEX compounds' impact on MTBE degradation are not well understood. We investigated trends in transcription of biodegradation genes in the MTBE-degrading bacterium, Methylibium petroleiphilum PM1 upon exposure to MTBE, TBA, ethylbenzene and benzene as individual compounds or in mixtures. We designed real-time quantitative PCR assays to target functional genes of strain PM1 and provide evidence for induction of genes mdpA (MTBE monooxygenase), mdpJ (TBA hydroxylase) and bmoA (benzene monooxygenase) in response to MTBE, TBA and benzene, respectively. Delayed induction of mdpA and mdpJ transcription occurred with mixtures of benzene and MTBE or TBA, respectively. bmoA transcription was similar in the presence of MTBE or TBA with benzene as in their absence. Our results also indicate that ethylbenzene, previously proposed as an inhibitor of MTBE degradation in some bacteria, inhibits transcription of mdpA, mdpJ and bmoAgenes in strain PM1.

Effect of benzene and ethylbenzene on the transcription of methyl-tert-butyl ether degradation genes of Methylibium petroleiphilum PM1

PubMed Central

Joshi, Geetika; Schmidt, Radomir; Scow, Kate M.; Denison, Michael S.; Hristova, Krassimira R.

2016-01-01

Methyl-tert-butyl ether (MTBE) and its degradation by-product, tert-butyl alcohol (TBA), are widespread contaminants detected frequently in groundwater in California. Since MTBE was used as a fuel oxygenate for almost two decades, leaking underground fuel storage tanks are an important source of contamination. Gasoline components such as BTEX (benzene, toluene, ethylbenzene and xylenes) are often present in mixtures with MTBE and TBA. Investigations of interactions between BTEX and MTBE degradation have not yielded consistent trends, and the molecular mechanisms of BTEX compounds’ impact on MTBE degradation are not well understood. We investigated trends in transcription of biodegradation genes in the MTBE-degrading bacterium, Methylibium petroleiphilum PM1 upon exposure to MTBE, TBA, ethylbenzene and benzene as individual compounds or in mixtures. We designed real-time quantitative PCR assays to target functional genes of strain PM1 and provide evidence for induction of genes mdpA (MTBE monooxygenase), mdpJ (TBA hydroxylase) and bmoA (benzene monooxygenase) in response to MTBE, TBA and benzene, respectively. Delayed induction of mdpA and mdpJ transcription occurred with mixtures of benzene and MTBE or TBA, respectively. bmoA transcription was similar in the presence of MTBE or TBA with benzene as in their absence. Our results also indicate that ethylbenzene, previously proposed as an inhibitor of MTBE degradation in some bacteria, inhibits transcription of mdpA, mdpJ and bmoAgenes in strain PM1. PMID:27450417

Mass balance of decabromodiphenyl ethane and decabromodiphenyl ether in a WWTP.

PubMed

Ricklund, Niklas; Kierkegaard, Amelie; McLachlan, Michael S; Wahlberg, Cajsa

2009-01-01

The additive flame retardant decabromodiphenyl ethane (deBDethane) has been identified in the environment, but little is known about its environmental behaviour. It is structurally similar to decabromodiphenyl ether (decaBDE), making it conceivable that it may also become an environmental contaminant of concern. In this study a mass balance of deBDethane and decaBDE was undertaken in a modern WWTP in Stockholm serving 7.05x10(5) inhabitants. Flow proportional samples of plant influent and effluent as well as daily grab samples of digested sludge were collected during two 7-day periods. All samples were analyzed with GC/HRMS using isotope labelled internal standards. The mean mass flows of deBDethane and decaBDE to the WWTP were 6.0 g per day and 55 g per day, respectively. Of this, less than 1% of both BFRs left the WWTP via the effluent, while the bulk was sequestered into the digested sludge, where the mean concentrations of deBDethane and decaBDE were 81 and 800 ng g(-1)d.wt., respectively. It is concluded that the transfer efficiency of deBDethane from the technosphere to the environment via WWTPs is similar to that of decaBDE.

Extraction and GC determination of volatile aroma compounds from extracts of three plant species of the Apiaceae family

NASA Astrophysics Data System (ADS)

Stan, M.; Soran, M. L.; Varodi, C.; Lung, I.; Copolovici, L.; MǎruÅ£oiu, C.

2013-11-01

Parsley (Petroselinum crispum), dill (Anethum graveolens) and celery (Apium graveolens), three aromatic plants belonging to the Apiaceae (Umbelliferae) botanical family, were selected as sources of essential or volatile oils. Essential oils are composed of a large diversity of volatile aroma compounds. Plant-derived essential oils and extracts have long been used as natural agents in food preservation, pharmaceuticals and medicinal therapies. In the present study, the plant extracts from leaves of parsley, dill and celery, were obtained by maceration, ultrasound-assisted extraction and microwave-assisted extraction. All extractions were performed at 30°C, using different solvents (ethanol, diethyl ether, n-hexane) and solvent mixtures (1:1, v/v). The most effective solvent system for the extraction of volatile aroma compounds was diethyl ether - n-hexane (1:1, v/v). Extraction efficiency and determination of aroma volatiles were performed by GC-FID and GC-MS, respectively. The major volatile compounds present in plant extracts were myristicin, α-phellandrene, β-phellandrene, 1,3,8-p-menthatriene, apiol, dill ether and allyl phenoxyacetate.

Catalyst activity maintenance study for the liquid phase dimethyl ether process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peng, X.D.; Toseland, B.A.; Underwood, R.P.

1995-12-31

The co-production of dimethyl ether (DME) and methanol from syngas is a process of considerable commercial attractiveness. DME coproduction can double the productivity of a LPMEOH process when using coal-derived syngas. This in itself may offer chemical producers and power companies increased flexibility and more profitable operation. DME is also known as a clean burning liquid fuel; Amoco and Haldor-Topsoe have recently announced the use of DME as an alternative diesel fuel. Moreover, DME can be an interesting intermediate in the production of chemicals such as olefins and vinyl acetate. The current APCl liquid phase dimethyl ether (LPDME) process utilizesmore » a physical mixture of a commercial methanol synthesis catalyst and a dehydration catalyst (e.g., {gamma}-alumina). While this arrangement provides a synergy that results in much higher syngas conversion per pass compared to the methanol-only process, the stability of the catalyst system suffers. The present project is aimed at reducing catalyst deactivation both by understanding the cause(s) of catalyst deactivation and by developing modified catalyst systems. This paper describes the current understanding of the deactivation mechanism.« less

The susceptibility critical exponent for a nonaqueous ionic binary mixture near a consolute point

NASA Technical Reports Server (NTRS)

Zhang, Kai C.; Briggs, Matthew E.; Gammon, Robert W.; Levelt Sengers, J. M. H.

1992-01-01

We report turbidity measurements of a nonaqueous ionic solution of triethyl n-hexylammonium triethyl n-hexylboride in diphenyl ether. A classical susceptibility critical exponent gamma = 1.01 +/- 0.01 is obtained over the reduced temperature range t between values of 0.1 and 0.0001. The best fits of the sample transmission had a standard deviation of 0.39 percent over this range. Ising and spherical model critical exponents are firmly excluded. The correlation length amplitude xi sub 0 from fitting is 1.0 +/- 0.2 nm which is much larger than values found in neutral fluids and some aqueous binary mixtures.

Use of aluminum phosphate as the dehydration catalyst in single step dimethyl ether process

DOEpatents

Peng, Xiang-Dong; Parris, Gene E.; Toseland, Bernard A.; Battavio, Paula J.

1998-01-01

The present invention pertains to a process for the coproduction of methanol and dimethyl ether (DME) directly from a synthesis gas in a single step (hereafter, the "single step DME process"). In this process, the synthesis gas comprising hydrogen and carbon oxides is contacted with a dual catalyst system comprising a physical mixture of a methanol synthesis catalyst and a methanol dehydration catalyst. The present invention is an improvement to this process for providing an active and stable catalyst system. The improvement comprises the use of an aluminum phosphate based catalyst as the methanol dehydration catalyst. Due to its moderate acidity, such a catalyst avoids the coke formation and catalyst interaction problems associated with the conventional dual catalyst systems taught for the single step DME process.

A New Approach to Highly Fluorinated Lubricants.

DTIC Science & Technology

1987-10-30

demonstrated the value of perfluoroalkyl groups being present. 7 In this way, xrious perfluoroethers were characterised, thus demonstrating the...mixture, containing four components (g.l.c. col. A 450C), was separated using preparative scale g.l.c. techniques to give:- perfluoropentane (4%); perfluoro ...CHRFOCHRFCH2 OCHRFCH 3 ) (where RF - CF 2CFHCF3 ) 2. These adducts were then fluorinated by cobalt trifluoride to give corresponding perfluoro -ethers

Polybrominated diphenyl ethers (PBDEs) in leachates from selected landfill sites in South Africa.

PubMed

Odusanya, David O; Okonkwo, Jonathan O; Botha, Ben

2009-01-01

The last few decades have seen dramatic growth in the scale of production and the use of polybrominated diphenyl ethers (PBDEs) as flame retardants. Consequently, PBDEs such as BDE -28, -47, -66, -71, -75, -77, -85, -99, -100, -119, -138, -153, -154, and -183 have been detected in various environmental matrices. Generally, in South Africa, once the products containing these chemicals have outlived their usefulness, they are discarded into landfill sites. Consequently, the levels of PBDEs in leachates from landfill sites may give an indication of the general exposure and use of these compounds. The present study was aimed at determining the occurrence and concentrations of most common PBDEs in leachates from selected landfill sites. The extraction capacities of the solvents were also tested. Spiked landfill leachate samples were used for the recovery tests. Separation and determination of the PBDE congeners were carried out with a gas chromatograph equipped with Ni63 electron capture detector. The mean percentage recoveries ranged from 63% to 108% (n=3) for landfill leachate samples with petroleum ether giving the highest percentage extraction. The mean concentrations of PBDEs obtained ranged from ND to 2670pgl(-1), ND to 6638pgl(-1), ND to 7230pgl(-1), 41 to 4009pgl(-1), 90 to 9793pgl(-1) for the Garankuwa, Hatherly, Kwaggarsrand, Soshanguve and Temba landfill sites, respectively. Also BDE -28, -47, -71 and BDE-77 were detected in the leachate samples from all the landfill sites; and all the congeners were detected in two of the oldest landfill sites. The peak concentrations were recorded for BDE-47 at three sites and BDE-71 and BDE-75 at two sites. The highest concentration, 9793+/-1.5pgl(-1), was obtained for the Temba landfill site with the highest BOD value. This may suggest some influence of organics on the level of PBDEs. Considering the leaching characteristics of brominated flame retardants, there is a high possibility that with time these compounds may infiltrate into the groundwater around the sites since most of the sites are not adequately lined.

Polybrominated diphenyl ethers (PBDEs) in leachates from selected landfill sites in South Africa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Odusanya, David O.; Okonkwo, Jonathan O.; Botha, Ben

The last few decades have seen dramatic growth in the scale of production and the use of polybrominated diphenyl ethers (PBDEs) as flame retardants. Consequently, PBDEs such as BDE -28, -47, -66, -71, -75, -77, -85, -99, -100, -119, -138, -153, -154, and -183 have been detected in various environmental matrices. Generally, in South Africa, once the products containing these chemicals have outlived their usefulness, they are discarded into landfill sites. Consequently, the levels of PBDEs in leachates from landfill sites may give an indication of the general exposure and use of these compounds. The present study was aimed atmore » determining the occurrence and concentrations of most common PBDEs in leachates from selected landfill sites. The extraction capacities of the solvents were also tested. Spiked landfill leachate samples were used for the recovery tests. Separation and determination of the PBDE congeners were carried out with a gas chromatograph equipped with Ni{sup 63} electron capture detector. The mean percentage recoveries ranged from 63% to 108% (n = 3) for landfill leachate samples with petroleum ether giving the highest percentage extraction. The mean concentrations of PBDEs obtained ranged from ND to 2670 pg l{sup -1}, ND to 6638 pg l{sup -1}, ND to 7230 pg l{sup -1}, 41 to 4009 pg l{sup -1}, 90 to 9793 pg l{sup -1} for the Garankuwa, Hatherly, Kwaggarsrand, Soshanguve and Temba landfill sites, respectively. Also BDE -28, -47, -71 and BDE-77 were detected in the leachate samples from all the landfill sites; and all the congeners were detected in two of the oldest landfill sites. The peak concentrations were recorded for BDE-47 at three sites and BDE-71 and BDE-75 at two sites. The highest concentration, 9793 {+-} 1.5 pg l{sup -1}, was obtained for the Temba landfill site with the highest BOD value. This may suggest some influence of organics on the level of PBDEs. Considering the leaching characteristics of brominated flame retardants, there is a high possibility that with time these compounds may infiltrate into the groundwater around the sites since most of the sites are not adequately lined.« less

Iron(II) catalysis in oxidation of hydrocarbons with ozone in acetonitrile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bataineh, Hajem; Pestovsky, Oleg; Bakac, Andreja

Oxidation of alcohols, ethers, and sulfoxides by ozone in acetonitrile is catalyzed by submillimolar concentrations of Fe(CH 3CN) 6 2+. The catalyst provides both rate acceleration and greater selectivity toward the less oxidized products. For example, Fe(CH 3CN) 6 2+-catalyzed oxidation of benzyl alcohol yields benzaldehyde almost exclusively (>95%), whereas the uncatalyzed reaction generates a 1:1 mixture of benzaldehyde and benzoic acid. Similarly, aliphatic alcohols are oxidized to aldehydes/ketones, cyclobutanol to cyclobutanone, and diethyl ether to a 1:1 mixture of ethanol and acetaldehyde. The kinetics of oxidation of alcohols and diethyl ether are first-order in [Fe(CH 3CN) 6 2+] andmore » [O 3] and independent of [substrate] at concentrations greater than ~5 mM. In this regime, the rate constant for all of the alcohols is approximately the same, k cat = (8 ± 1) × 10 4 M –1 s –1, and that for (C 2H 5) 2O is (5 ± 0.5) × 10 4 M –1 s –1. In the absence of substrate, Fe(CH 3CN) 6 2+ reacts with O 3 with k Fe = (9.3 ± 0.3) × 10 4 M –1 s –1. The similarity between the rate constants k Fe and k cat strongly argues for Fe(CH 3CN) 6 2+/O 3 reaction as rate-determining in catalytic oxidation. The active oxidant produced in Fe(CH 3CN) 6 2+/O 3 reaction is suggested to be an Fe(IV) species in analogy with a related intermediate in aqueous solutions. As a result, this assignment is supported by the similarity in kinetic isotope effects and relative reactivities of the two species toward substrates.« less

Iron(II) catalysis in oxidation of hydrocarbons with ozone in acetonitrile

DOE PAGES

Bataineh, Hajem; Pestovsky, Oleg; Bakac, Andreja

2015-02-11

Oxidation of alcohols, ethers, and sulfoxides by ozone in acetonitrile is catalyzed by submillimolar concentrations of Fe(CH 3CN) 6 2+. The catalyst provides both rate acceleration and greater selectivity toward the less oxidized products. For example, Fe(CH 3CN) 6 2+-catalyzed oxidation of benzyl alcohol yields benzaldehyde almost exclusively (>95%), whereas the uncatalyzed reaction generates a 1:1 mixture of benzaldehyde and benzoic acid. Similarly, aliphatic alcohols are oxidized to aldehydes/ketones, cyclobutanol to cyclobutanone, and diethyl ether to a 1:1 mixture of ethanol and acetaldehyde. The kinetics of oxidation of alcohols and diethyl ether are first-order in [Fe(CH 3CN) 6 2+] andmore » [O 3] and independent of [substrate] at concentrations greater than ~5 mM. In this regime, the rate constant for all of the alcohols is approximately the same, k cat = (8 ± 1) × 10 4 M –1 s –1, and that for (C 2H 5) 2O is (5 ± 0.5) × 10 4 M –1 s –1. In the absence of substrate, Fe(CH 3CN) 6 2+ reacts with O 3 with k Fe = (9.3 ± 0.3) × 10 4 M –1 s –1. The similarity between the rate constants k Fe and k cat strongly argues for Fe(CH 3CN) 6 2+/O 3 reaction as rate-determining in catalytic oxidation. The active oxidant produced in Fe(CH 3CN) 6 2+/O 3 reaction is suggested to be an Fe(IV) species in analogy with a related intermediate in aqueous solutions. As a result, this assignment is supported by the similarity in kinetic isotope effects and relative reactivities of the two species toward substrates.« less

Direct screening of ground water samples for fuel oxygenates by headspace liquid phase microextraction-gas chromatography.

PubMed

Kaykhaii, Massoud; Mirbaloochzahi, Mohammad Reza

2008-12-01

The applicability of the headspace liquid phase microextraction and gas chromatography (HS-LPME/GC) for the expeditious and reliable screening of 68 well water samples for selected fuel oxygenates compounds, viz. methyl tertiary-butyl ether (MTBE), tertiary-amyl methyl ether (TAME), ethyl tertiary-butyl ether (ETBE) and n-butyl ethyl ether (n-BEE) has been evaluated. The method used 3 microl of 1:1 benzyl alcohol/1-octanol as extraction solvent, 20 min extraction time with stirring at 1,250 rpm, at 20 degrees C and salt addition of a mixture of 0.3 g ml(-1) sodium sulphate/0.1 g ml(-1) sodium chloride. The enrichment factors of this method were from 171 to 571. Limits of detection were in the range of 77-110 ng l(-1). The relative standard deviations (RSDs) at 0.05, 0.50 and 10.0 mg l(-1) of spiking levels were in the range of 1.28-6.80% with recoveries between 96.2 and 106.0%. Sixty-eight groundwater wells that were located near different gasoline reservoirs in eight largest cities of the Sistan and Balouchestan province were screened by the method. Eight contaminated wells were identified contained MTBE at levels between 0.3 and 1.7 mg l(-1). In all cases, other target analytes were at low concentrations or not detected.

Suitability of polydimethylsiloxane rods for the headspace sorptive extraction of polybrominated diphenyl ethers from water samples.

PubMed

Montes, R; Rodríguez, I; Rubí, E; Cela, R

2007-03-02

The suitability of an inexpensive polydimethysiloxane (PDMS) sorbent, produced on an industrial scale, for the extraction of polybrominated diphenyl ethers (PBDEs), from tetra- to hexabrominated congeners, from water samples was assessed. Experiments were carried out using samples spiked with a pentabromo diphenyl ether (pentaBDE) mixture, PDMS rods with a diameter of 2 mm and gas chromatography with micro-electron-capture detection (GC-micro-ECD). Influence of several variables on the efficiency of the enrichment step and the further desorption of the analytes was investigated in detail. The best performance was achieved in the headspace sorptive extraction (HSSE) mode, at 95 degrees C, using 80 mL water samples containing a 30% of sodium chloride. Extractions were performed overnight using disposable PDMS rods with a length of 10 mm (31 microL volume). Analytes were further recovered from the PDMS sorbent using just 1 mL of diethyl ether. This solvent was evaporated and extracts reconstituted with 25 microL of isooctane. Under final working conditions absolute extraction efficiencies from 69 to 93% and enrichment factors higher than 2200 folds were achieved for all species. The proposed method provided acceptable precisions (relative standard deviations values under 12%), correlation coefficients higher than 0.998 and the yield of the HSSE process remained constant for different water samples.

A study on flammability limits of fuel mixtures.

PubMed

Kondo, Shigeo; Takizawa, Kenji; Takahashi, Akifumi; Tokuhashi, Kazuaki; Sekiya, Akira

2008-07-15

Flammability limit measurements were made for various binary and ternary mixtures prepared from nine different compounds. The compounds treated are methane, propane, ethylene, propylene, methyl ether, methyl formate, 1,1-difluoroethane, ammonia, and carbon monoxide. The observed values of lower flammability limits of mixtures were found to be in good agreement to the calculated values by Le Chatelier's formula. As for the upper limits, however, some are close to the calculated values but some are not. It has been found that the deviations of the observed values of upper flammability limits from the calculated ones are mostly to lower concentrations. Modification of Le Chatelier's formula was made to better fit to the observed values of upper flammability limits. This procedure reduced the average difference between the observed and calculated values of upper flammability limits to one-third of the initial value.

Equilibration of a polycation - anionic surfactant mixture at the water/vapor interface.

PubMed

Akanno, Andrew; Guzmán, Eduardo; Fernández-Peña, Laura; Llamas, Sara; Ortega, Francisco; Rubio, Ramon Gonzalez

2018-06-01

The adsorption of concentrated poly(diallyldimethylammonium chloride) (PDADMAC) - sodium lauryl ether sulfate (SLES) mixtures at the water / vapor interface has been studied by different surface tension techniques and dilational visco-elasticity measurements. This work tries to shed light on the way in which the formation of polyelectrolyte - surfactant complexes in the bulk affects to the interfacial properties of mixtures formed by a polycation and an oppositely charged surfactant. The results are discussed in terms of a two-step adsorption-equilibration of PDADMAC - SLES complexes at the interface, with the initial stages involving the diffusion of kinetically trapped aggregates formed in the bulk to the interface followed by the dissociation and spreading of such aggregates at the interface. This latter process becomes the main contribution to the surface tension decrease. This work helps on the understanding of the most fundamental bases of the physico-chemical behavior of concentrated polyelectrolyte - surfactant mixtures which present complex bulk and interfacial interactions with interest in both basic and applied sciences.

Absorption degree analysis on biogas separation with ionic liquid systems.

PubMed

Zhang, Xin; Zhang, Suojiang; Bao, Di; Huang, Ying; Zhang, Xiangping

2015-01-01

For biogas upgrading, present work mainly focuses on either thermodynamics or mass transfer properties. A systematical study on these two aspects is important for developing a new biogas separation process. In this work, a new criterion "absorption degree", which combines both thermodynamics and mass transfer properties, was proposed for the first time to comprehensively evaluate the absorption performance. Henry's law constants of CO2 and CH4 in ionic liquids-polyethylene glycol dimethyl ethers mixtures were investigated. The liquid-side mass transfer coefficients (kL) were determined. The results indicate that IL-NHD mixtures exhibit not only a high CO2/CH4 selectivity, but also a fast kL for CO2 absorption. The [bmim][NO3]+NHD mixtures present a high absorption degree value for CO2 but a low value for CH4. For presenting a highest relative absorption degree value, the 50wt% [bmim][NO3]+50wt% NHD mixture is recommended for biogas upgrading. Copyright © 2014 Elsevier Ltd. All rights reserved.

Homogeneous catalyst formulations for methanol production

DOEpatents

Mahajan, Devinder; Sapienza, Richard S.; Slegeir, William A.; O'Hare, Thomas E.

1991-02-12

There is disclosed synthesis of CH.sub.3 OH from carbon monoxide and hydrogen using an extremely active homogeneous catalyst for methanol synthesis directly from synthesis gas. The catalyst operates preferably between 100.degree.-150.degree. C. and preferably at 100-150 psia synthesis gas to produce methanol. Use can be made of syngas mixtures which contain considerable quantities of other gases, such as nitrogen, methane or excess hydrogen. The catalyst is composed of two components: (a) a transition metal carbonyl complex and (b) an alkoxide component. In the simplest formulation, component (a) is a complex of nickel tetracarbonyl and component (b) is methoxide (CH.sub.3 O.sup.-), both being dissolved in a methanol solvent system. The presence of a co-solvent such as p-dioxane, THF, polyalcohols, ethers, hydrocarbons, and crown ethers accelerates the methanol synthesis reaction.

Homogeneous catalyst formulations for methanol production

DOEpatents

Mahajan, Devinder; Sapienza, Richard S.; Slegeir, William A.; O'Hare, Thomas E.

1990-01-01

There is disclosed synthesis of CH.sub.3 OH from carbon monoxide and hydrogen using an extremely active homogeneous catalyst for methanol synthesis directly from synthesis gas. The catalyst operates preferably between 100.degree.-150.degree. C. and preferably at 100-150 psia synthesis gas to produce methanol. Use can be made of syngas mixtures which contain considerable quantities of other gases, such as nitrogen, methane or excess hydrogen. The catalyst is composed of two components: (a) a transition metal carbonyl complex and (b) an alkoxide component. In the simplest formulation, component (a) is a complex of nickel tetracarbonyl and component (b) is methoxide (CH.sub.3 O.sup.13 ), both being dissolved in a methanol solvent system. The presence of a co-solvent such as p-dioxane, THF, polyalcohols, ethers, hydrocarbons, and crown ethers accelerates the methanol synthesis reaction.

Laminar Flame Velocity and Temperature Exponent of Diluted DME-Air Mixture

NASA Astrophysics Data System (ADS)

Naseer Mohammed, Abdul; Anwar, Muzammil; Juhany, Khalid A.; Mohammad, Akram

2017-03-01

In this paper, the laminar flame velocity and temperature exponent diluted dimethyl ether (DME) air mixtures are reported. Laminar premixed mixture of DME-air with volumetric dilutions of carbon dioxides (CO2) and nitrogen (N2) are considered. Experiments were conducted using a preheated mesoscale high aspect-ratio diverging channel with inlet dimensions of 25 mm × 2 mm. In this method, flame velocities are extracted from planar flames that were stabilized near adiabatic conditions inside the channel. The flame velocities are then plotted against the ratio of mixture temperature and the initial reference temperature. A non-linear power law regression is observed suitable. This regression analysis gives the laminar flame velocity at the initial reference temperature and temperature exponent. Decrease in the laminar flame velocity and increase in temperature exponent is observed for CO2 and N2 diluted mixtures. The addition of CO2 has profound influence when compared to N2 addition on both flame velocity and temperature exponent. Numerical prediction of the similar mixture using a detailed reaction mechanism is obtained. The computational mechanism predicts higher magnitudes for laminar flame velocity and smaller magnitudes of temperature exponent compared to experimental data.

Toughening reinforced epoxy composites with brominated polymeric additives

NASA Technical Reports Server (NTRS)

Nir, Z. (Inventor); Gilwee, W. J., Jr. (Inventor)

1985-01-01

Cured polyfunctional epoxy resins including tris(hydroxyphenyl)methane triglycidyl ether are toughened by addition of polybrominated polymeric additives having an EE below 1500 to the pre-cure composition. Carboxy-terminated butadiene-acrylonitrile rubber is optionally present in the pre-cure mixture as such or as a pre-formed copolymer with other reactants. Reinforced composites, particularly carbon-reinforced composites, of these resins are disclosed and shown to have improved toughness.

Electronics Manufacturing Seminar Proceedings. 17th Annual

DTIC Science & Technology

1992-12-01

a CFC Solvent Cleaning Alternative Page 3 In operation dirty parts are immersed in the boil cham- ber where they contact the agitated mixture of...component. Some glycol ethers have an uncertain regulatory future due to a variety of health concerns. Semi-aqueous solvents can have a strong odor . Proper...thermoset 5 materials, elastomers, marking inks, sealants, and locking compounds after repeated exposure to the selected cleaners. Epoxy and polyimide PWBs

Toughening reinforced epoxy composites with brominated polymeric additives

NASA Technical Reports Server (NTRS)

Nir, Z.; Gilwee, W. J., Jr. (Inventor)

1985-01-01

Cured polyfunctional epoxy resins including tris (hydroxyphenyl) methane triglycidyl ether are toughened by addition of polybrominated polymeric additives having an EE below 1500 to the pre-cure composition. Carboxy terminated butadiene acrylonitrile rubber is optionally present in the precure mixture as such or as a pre-formed copolymer with other reactants. Reinforced composites, particularly carbon reinforced composites, of these resins are disclosed and shown to have improved toughness.

SOLVENT EXTRACTION OF RUTHENIUM

DOEpatents

Hyman, H.H.; Leader, G.R.

1959-07-14

The separation of rathenium from aqueous solutions by solvent extraction is described. According to the invention, a nitrite selected from the group consisting of alkali nitrite and alkaline earth nitrite in an equimolecular quantity with regard to the quantity of rathenium present is added to an aqueous solution containing ruthenium tetrantrate to form a ruthenium complex. Adding an organic solvent such as ethyl ether to the resulting mixture selectively extracts the rathenium complex.

A predictive multi-linear regression model for organic micropollutants, based on a laboratory-scale column study simulating the river bank filtration process.

PubMed

Bertelkamp, C; Verliefde, A R D; Reynisson, J; Singhal, N; Cabo, A J; de Jonge, M; van der Hoek, J P

2016-03-05

This study investigated relationships between OMP biodegradation rates and the functional groups present in the chemical structure of a mixture of 31 OMPs. OMP biodegradation rates were determined from lab-scale columns filled with soil from RBF site Engelse Werk of the drinking water company Vitens in The Netherlands. A statistically significant relationship was found between OMP biodegradation rates and the functional groups of the molecular structures of OMPs in the mixture. The OMP biodegradation rate increased in the presence of carboxylic acids, hydroxyl groups, and carbonyl groups, but decreased in the presence of ethers, halogens, aliphatic ethers, methyl groups and ring structures in the chemical structure of the OMPs. The predictive model obtained from the lab-scale soil column experiment gave an accurate qualitative prediction of biodegradability for approximately 70% of the OMPs monitored in the field (80% excluding the glymes). The model was found to be less reliable for the more persistent OMPs (OMPs with predicted biodegradation rates lower or around the standard error=0.77d(-1)) and OMPs containing amide or amine groups. These OMPs should be carefully monitored in the field to determine their removal during RBF. Copyright © 2015 Elsevier B.V. All rights reserved.

New ether-functionalized ionic liquids for lipase-catalyzed synthesis of biodiesel.

PubMed

Zhao, Hua; Song, Zhiyan; Olubajo, Olarongbe; Cowins, Janet V

2010-09-01

Ionic liquids (ILs) are being explored as solvents for the enzymatic methanolysis of triglycerides. However, most available ILs (especially hydrophobic ones) have poor capability in dissolving lipids, while hydrophilic ILs tend to cause enzyme inactivation. Recently, we synthesized a new type of ether-functionalized ionic liquids (ILs) carrying anions of acetate or formate; they are capable of dissolving a variety of substrates and are also lipase-compatible (Green Chem., 2008, 10, 696-705). In the present study, we carried out the lipase-catalyzed transesterifications of Miglyol oil 812 and soybean oil in these novel ILs. These ILs are capable of dissolving oils at the reaction temperature (50 degrees C); meanwhile, lipases maintained high catalytic activities in these media even in high concentrations of methanol (up to 50% v/v). High conversions of Miglyol oil were observed in mixtures of IL and methanol (70/30, v/v) when the reaction was catalyzed by a variety of lipases and different enzyme preparations (free and immobilized), especially with the use of two alkylammonium ILs 2 and 3. The preliminary study on the transesterification of soybean oil in IL/methanol mixtures further confirms the potential of using oil-dissolving and lipase-stabilizing ILs in the efficient production of biodiesels.

Cascade Reductive Etherification of Bioderived Aldehydes over Zr-Based Catalysts.

PubMed

Shinde, Suhas; Rode, Chandrashekhar

2017-10-23

An efficient one-pot catalytic cascade sequence has been developed for the production of value-added ethers from bioderived aldehydes. Etherification of 5-(hydroxymethyl)furfural with different aliphatic alcohols over acidic Zr-montmorillonite (Zr-Mont) catalyst produced a mixture of 5-(alkoxymethyl)furfural and 2-(dialkoxymethyl)-5-(alkoxymethyl)furan. The latter was selectively converted back into 5-(alkoxymethyl)furfural by treating it with water over the same catalyst. The synthesis of 2,5-bis(alkoxymethyl)furan was achieved through a cascade sequence involving etherification, transfer hydrogenation, and re-etherification over a combination of acidic Zr-Mont and the charge-transfer hydrogenation catalyst [ZrO(OH) 2 ]. This catalyst combination was further explored for the cascade conversion of 2-furfuraldehyde into 2-(alkoxymethyl)furan. The scope of this strategy was then extended for the reductive etherification of lignin-derived arylaldehydes to obtain the respective benzyl ethers in >80 % yield. Additionally, the mixture of Zr-Mont and ZrO(OH) 2 does not undergo mutual destruction, which was proved by recycling experiments and XRD analysis. Both the catalysts were thoroughly characterized using BET, temperature-programmed desorption of NH 3 and CO 2 , pyridine-FTIR, XRD, inductively coupled plasma optical emission spectroscopy, and X-ray photoelectron spectroscopy techniques. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Occurrence of polybrominated diphenyl ethers in floor and elevated surface house dust from Shanghai, China.

PubMed

Niu, Dong; Qiu, Yanling; Li, Li; Zhou, Yihui; Du, Xinyu; Zhu, Zhiliang; Chen, Ling; Lin, Zhifen

2018-04-24

House dust is the main source of human exposure to flame retardants by ingestion. This study investigated the occurrence of polybrominated diphenyl ethers (PBDEs) in indoor dust from 22 houses in Shanghai, China. House dust was separately collected from the floor and elevated furnishings surface (mostly between 0.5 and 2 m height) for comparison. The concentrations of ∑ 22 PBDEs ranged from 19.4 to 3280 ng/g (with a geometric mean of 203 ng/g) and from 55.1 to 792 ng/g (with a geometric mean of 166 ng/g) in floor dust (FD) and elevated surface dust (ESD), respectively. BDE-209 was the predominant congener, accounting for about 73.1% of total PBDE burdens. In terms of congener profiles, the comparison of FD and ESD revealed no significant differences except for the ratio of BDE-47/BDE-99. ESD samples displayed a ratio of BDE-47/BDE-99 very similar to commercial penta-BDE products DE-71 while the ratio in FD was exceptionally higher. Significant correlation was found between concentrations of commercial penta-BDE compositions in FD and ESD (p < 0.05). Except for some occasional values, PBDE levels in house dust exhibited temporal stability. Human exposure to PBDEs via dust ingestion was estimated. The highest daily intake of PBDEs was for toddlers by using 95th percentile concentrations of PBDEs via high dust ingestion in FD (23.07 ng/kg bw/day). About 20-fold difference in exposure estimates between toddlers and adults supports that toddlers are facing greater risk from indoor floor dust. Expectedly, this study highlighted the point that residents in Shanghai were exposed to low doses of PBDEs in house dust.

Isopycnic Phases and Structures in H2O/CO2/Ethoxylated Alcohol Surfactant Mixtures

NASA Technical Reports Server (NTRS)

Paulaitis, Michael E.; Zielinski, Richard G.; Kaler, Eric W.

1996-01-01

Ternary mixtures of H2O and CO2 with ethoxylated alcohol (C(i)E(j)) surfactants can form three coexisting liquid phases at conditions where two of the phases have the same density (isopycnic phases). Isopycnic phase behavior has been observed for mixtures containing the surfactants C8E5, C10E6, and C12E6, but not for those mixtures containing either C4E1 or CgE3. Pressure-temperature (PT) projections for this isopycnic three-phase equilibrium were determined for H2O/CO2/C8E5 and H2O/CO2/C10E6 mixtures at temperatures from approximately 25 to 33 C and pressures between 90 and 350 bar. As a preliminary to measuring the microstructure in isopycnic three component mixtures, phase behavior and small angle neutron scattering (SANS) experiments were performed on mixtures of D2O/CO2/ n-hexaethyleneglycol monododecyl ether (C12E6) as a function of temperature (25-31 C), pressure (63.1-90.7 bar), and CO2 composition (0-3.9 wt%). Parameters extracted from model fits of the SANS spectra indicate that, while micellar structure remains essentially unchanged, critical concentration fluctuations increase as the phase boundary and plait point are approached.

Gas chromatography with mass spectrometry for the quantification of ethylene glycol ethers in different household cleaning products.

PubMed

Pastor-Belda, Marta; Campillo, Natalia; Hernández-Córdoba, Manuel; Viñas, Pilar

2016-06-01

A rapid and simple procedure is reported for the determination of six ethylene glycol ethers in cleaning products and detergents using gas chromatography with mass spectrometry. The analytes were extracted from 2.0 g samples in acetonitrile (3 mL) and the extract was submitted to a clean-up step by QuEChERS method, using a mixture containing 0.3 g magnesium sulfate, 0.15 g primary/secondary amine, and 0.05 g C18 . The clean acetonitrile extract (1 μL) was injected into the chromatographic system. No matrix effect was observed, so the quantification of the samples was carried out against external standards. Detection limits were in the range 3.0-27 ng/g for the six ethylene glycol ethers. The recoveries obtained, using the optimized procedure, were in the 89.4-118% range, with relative standard deviations lower than 14%. Twenty-three different household cleaning products, including glass cleaner, degreaser, floor, softeners, and clothes and dishwashing detergents, were analyzed. Large interindividual variations were observed between samples and compounds. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemical Clearing and Dehydration of GFP Expressing Mouse Brains

PubMed Central

Saghafi, Saiedeh; Weiler, Reto; Dodt, Hans-Ulrich

2012-01-01

Generally, chemical tissue clearing is performed by a solution consisting of two parts benzyl benzoate and one part benzyl alcohol. However, prolonged exposure to this mixture markedly reduces the fluorescence of GFP expressing specimens, so that one has to compromise between clearing quality and fluorescence preservation. This can be a severe drawback when working with specimens exhibiting low GFP expression rates. Thus, we screened for a substitute and found that dibenzyl ether (phenylmethoxymethylbenzene, CAS 103-50-4) can be applied as a more GFP-friendly clearing medium. Clearing with dibenzyl ether provides improved tissue transparency and strikingly improved fluorescence intensity in GFP expressing mouse brains and other samples as mouse spinal cords, or embryos. Chemical clearing, staining, and embedding of biological samples mostly requires careful foregoing tissue dehydration. The commonly applied tissue dehydration medium is ethanol, which also can markedly impair GFP fluorescence. Screening for a substitute also for ethanol we found that tetrahydrofuran (CAS 109-99-9) is a more GFP-friendly dehydration medium than ethanol, providing better tissue transparency obtained by successive clearing. Combined, tetrahydrofuran and dibenzyl ether allow dehydration and chemical clearing of even delicate samples for UM, confocal microscopy, and other microscopy techniques. PMID:22479475

Chemical clearing and dehydration of GFP expressing mouse brains.

PubMed

Becker, Klaus; Jährling, Nina; Saghafi, Saiedeh; Weiler, Reto; Dodt, Hans-Ulrich

2012-01-01

Generally, chemical tissue clearing is performed by a solution consisting of two parts benzyl benzoate and one part benzyl alcohol. However, prolonged exposure to this mixture markedly reduces the fluorescence of GFP expressing specimens, so that one has to compromise between clearing quality and fluorescence preservation. This can be a severe drawback when working with specimens exhibiting low GFP expression rates. Thus, we screened for a substitute and found that dibenzyl ether (phenylmethoxymethylbenzene, CAS 103-50-4) can be applied as a more GFP-friendly clearing medium. Clearing with dibenzyl ether provides improved tissue transparency and strikingly improved fluorescence intensity in GFP expressing mouse brains and other samples as mouse spinal cords, or embryos. Chemical clearing, staining, and embedding of biological samples mostly requires careful foregoing tissue dehydration. The commonly applied tissue dehydration medium is ethanol, which also can markedly impair GFP fluorescence. Screening for a substitute also for ethanol we found that tetrahydrofuran (CAS 109-99-9) is a more GFP-friendly dehydration medium than ethanol, providing better tissue transparency obtained by successive clearing. Combined, tetrahydrofuran and dibenzyl ether allow dehydration and chemical clearing of even delicate samples for UM, confocal microscopy, and other microscopy techniques.

Pentan isomers compound flame front structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mansurov, Z.A.; Mironenko, A.W.; Bodikov, D.U.

1995-08-13

The fuels (hexane, pentane, diethyl ether) and conditions investigated in this study are relevant to engine knock in spark- ignition engines. A review is provided of the field of low temperature hydrocarbon oxidation. Studies were made of radical and stable intermediate distribution in the front of cool flames: Maximum concentrations of H atoms and peroxy radicals were observed in the luminous zone of the cool flame front. Peroxy radicals appear before the luminous zone at 430 K due to diffusion. H atoms were found in cool flames of butane and hexane. H atoms diffuses from the luminous zone to themore » side of the fresh mixture, and they penetrate into the fresh mixture to a small depth. Extension of action sphear of peroxy radicals in the fresh mixture is much greater than that of H atoms due to their small activity and high concentrations.« less

Differential scanning calorimetric study of nonionic surfactant mixtures with a room temperature ionic liquid, bmimBF4.

PubMed

Inoue, Tohru; Higuchi, Yuka; Misono, Takeshi

2009-10-01

The melting behavior of polyethyleneglycol dodecyl ethers (C(12)E(6), C(12)E(7), and C(12)E(8)) in a room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)), was investigated by means of differential scanning calorimetry (DSC). The melting temperature as a function of the surfactant concentration, combined with the cmc curve and cloud point curve, provided phase diagrams for the surfactant/bmimBF(4) mixtures in solvent-rich region. The characteristic feature of the mixtures is an existence of the Krafft temperature which is usually not observed with aqueous solutions of nonionic surfactants. The heat of fusion as a function of the surfactant concentration provided the interaction energy between the surfactant and bmimBF(4). The interaction energy shows a linear dependence on the length of polyoxyethylene (POE) chain of the surfactants, which suggests that the solvation takes place around the POE chain.

Study of dynamic emission spectra from lubricant films in an elastohydrodynamic contact using Fourier transform spectroscopy

NASA Technical Reports Server (NTRS)

Lauer, J. L.

1978-01-01

Infrared emission spectra were obtained through a diamond window from lubricating fluids in an operating sliding elastohydrodynamic contact and analyzed by comparison with static absorption spectra under similar pressures. Different loads, shear rates and temperatures were used. Most of the spectra exhibited polarization characteristics, indicating directional alignment of the lubricant in the EHD contact. Among the fluids studied were a "traction" fluid, an advanced ester, and their mixtures, a synthetic paraffin, a naphthenic reference fluid (N-1), both neat and containing 1 percent of p-tricresyl phosphate as an anti-wear additive, and a C-ether. Traction properties were found to be nearly proportional to mixture composition for traction fluid and ester mixtures. The anti-wear additive reduced traction and fluid temperature under low loads but increased them under higher loads, giving rise to formation of a friction polymer.

Simultaneous determination of triacetin, acetic ether, butyl acetate and amorolfine hydrochloride in amorolfine liniment by HPLC.

PubMed

Gao, Yuan; Li, Li; Zhang, Jianjun; Shu, Wenjuan; Gao, Liqiong

2012-04-01

A simple, rapid, specific and precise reversed-phase high-performance liquid chromatographic method was developed for simultaneous estimation of triacetin, acetic ether, butyl acetate and amorolfine in marketed pharmaceutical liniment. Chromatographic separation was performed on a Shimadzu VP-ODS C(18) column using the mixture of citric acid-hydrochloric acid-sodium hydrate buffer (pH 3.0), acetonitrile and methanol (32:30:38) as the mobile phase at a flow rate of 1.0 mL/min with UV-detection at 215 nm. The method separated the four components simultaneously in less than 10 min. The validation of the method was performed with respect to specificity, linearity, accuracy, and precision. The calibration curves were linear in the range of 35.1-81.9 μ/mL for triacetin, 431.1-1005.9 μ/mL for acetic ether, 167.0-389.7 μ/mL for butyl acetate and 151.0-352.3 μ/mL for amorolfine. The mean 100% spiked recovery for triacetin, acetic ether, butyl acetate and amorolfine is 99.43 ± 0.42, 101.5 ± 1.09, 101.4 ± 1.02 and 100.8 ± 0.69, respectively. The intra-day and inter-day relative standard deviation values were <2.0%. The limits of detection of these compounds ranged from 0.08 to 5.88 ng. The utility of the procedure was verified by its application to the commercial liniment.

Improvement of electrochemical performances of sulfonated poly(arylene ether sulfone) via incorporation of sulfonated poly(arylene ether benzimidazole)

NASA Astrophysics Data System (ADS)

Hong, Young Taik; Lee, Chang Hyun; Park, Hyung Su; Min, Kyung A.; Kim, Hyung Joong; Nam, Sang Yong; Lee, Young Moo

In the present study, modified acid-base blend membranes were fabricated via incorporation of sulfonated poly(arylene ether benzimidazole) (SPAEBI) into sulfonated poly(arylene ether sulfone) (SPAES). These membranes had excellent methanol-barrier properties in addition to an ability to compensate for the loss of proton conductivity that typically occurs in general acid-base blend system. To fabricate the membranes, SPAEBIs, which served as amphiphilic polymers with different degrees of sulfonation (0-50 mol%), were synthesized by polycondensation and added to SPAES. It resulted in the formation of acid-amphiphilic complexes such as [PAES-SO 3] - +[H-SPAEBI] through the ionic crosslinking, which prevented SO 3H groups in the complex from transporting free protons in an aqueous medium, contributing to a reduction of ion exchange capacity values and water uptake in the blend membranes, and leading to lower methanol permeability in a water-methanol mixture. Unfortunately, the ionic bonding formation was accompanied by a decrease of bound water content and proton conductivity, although the latter problem was solved to some extent by the incorporation of additional SO 3H groups in SPAEBI. In the SPAES-SPAEBI blend membranes, enhancement of proton conductivity and methanol-barrier property was prominent at temperatures over 90 °C. The direct methanol fuel cell (DMFC) performance, which was based on SPAES-SPAEBI-50-5, was 1.2 times higher than that of Nafion ® 117 under the same operating condition.

Synthetic Polymers as Gasoline Thickening Agents

DTIC Science & Technology

1944-10-02

Polyvinyl Ethers —---- 71 2. Vistanex and Synthetic Rubbers — 73 3. Ethyl Cellulose 7* a. Solubility Studies 75 b. Gel Preparation — 75 c...Surveillance Tests —- 77 d. Static Firing Tests 78 e. Ethyl Cellulose as a Methacrylate Extender 78 f. Modification of Ethyl Cellulose 78 4...Miscellaneous Polymers 79 5. Emulsions 81 6. Pactices 81 B. Preparation of Polymers not nov in Commercial Production— ---——--— 81 1. Cellulose Esters

Actinide extraction methods

DOEpatents

Peterman, Dean R [Idaho Falls, ID; Klaehn, John R [Idaho Falls, ID; Harrup, Mason K [Idaho Falls, ID; Tillotson, Richard D [Moore, ID; Law, Jack D [Pocatello, ID

2010-09-21

Methods of separating actinides from lanthanides are disclosed. A regio-specific/stereo-specific dithiophosphinic acid having organic moieties is provided in an organic solvent that is then contacted with an acidic medium containing an actinide and a lanthanide. The method can extend to separating actinides from one another. Actinides are extracted as a complex with the dithiophosphinic acid. Separation compositions include an aqueous phase, an organic phase, dithiophosphinic acid, and at least one actinide. The compositions may include additional actinides and/or lanthanides. A method of producing a dithiophosphinic acid comprising at least two organic moieties selected from aromatics and alkyls, each moiety having at least one functional group is also disclosed. A source of sulfur is reacted with a halophosphine. An ammonium salt of the dithiophosphinic acid product is precipitated out of the reaction mixture. The precipitated salt is dissolved in ether. The ether is removed to yield the dithiophosphinic acid.

Vapor Pressure of Three Brominated Flame Retardants Determined via Knudsen Effusion Method

PubMed Central

Fu, Jinxia; Suuberg, Eric M.

2012-01-01

Brominated flame retardants (BFRs) have been used in a variety of consumer products in the past four decades. The vapor pressures for three widely used BFRs, that is, tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD), and octabromodiphenyl ethers (octaBDEs) mixtures, were determined using the Knudsen effusion method and compared to those of decabromodiphenyl ether (BDE209). The values measured extrapolated to 298.15 K are 8.47 × 10−9, 7.47 × 10−10, and 2.33 × 10−9 Pa, respectively. The enthalpies of sublimation for these BFRs were estimated using the Clausius-Clapeyron equation and are 143.6 ± 0.4, 153.7 ± 3.1, and 150.8 ± 3.2 kJ/mole, respectively. In addition, the enthalpies of fusion and melting temperatures for these BFRs were also measured in the present study. PMID:22213441

Enzymatic Addition of Alcohols to Terpenes by Squalene Hopene Cyclase Variants.

PubMed

Kühnel, Lisa C; Nestl, Bettina M; Hauer, Bernhard

2017-11-16

Squalene-hopene cyclases (SHCs) catalyze the polycyclization of squalene into a mixture of hopene and hopanol. Recently, amino-acid residues lining the catalytic cavity of the SHC from Alicyclobacillus acidocaldarius were replaced by small and large hydrophobic amino acids. The alteration of leucine 607 to phenylalanine resulted in increased enzymatic activity towards the formation of an intermolecular farnesyl-farnesyl ether product from farnesol. Furthermore, the addition of small-chain alcohols acting as nucleophiles led to the formation of non-natural ether-linked terpenoids and, thus, to significant alteration of the product pattern relative to that obtained with the wild type. It is proposed that the mutation of leucine at position 607 may facilitate premature quenching of the intermediate by small alcohol nucleophiles. This mutagenesis-based study opens the field for further intermolecular bond-forming reactions and the generation of non-natural products. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Oxidation resistant organic hydrogen getters

DOEpatents

Shepodd, Timothy J [Livermore, CA; Buffleben, George M [Tracy, CA

2008-09-09

A composition for removing hydrogen from an atmosphere, comprising a mixture of a polyphenyl ether and a hydrogenation catalyst, preferably a precious metal catalyst, and most preferably Pt. This composition is stable in the presence of oxygen, will not polymerize or degrade upon exposure to temperatures in excess of 200.degree. C., or prolonged exposure to temperatures in the range of 100-300.degree. C. Moreover, these novel hydrogen getter materials can be used to efficiently removing hydrogen from mixtures of hydrogen/inert gas (e.g., He, Ar, N.sub.2), hydrogen/ammonia atmospheres, such as may be encountered in heat exchangers, and hydrogen/carbon dioxide atmospheres. Water vapor and common atmospheric gases have no adverse effect on the ability of these getter materials to absorb hydrogen.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Underwood, R.P.

As part of the DOE-sponsored contract Synthesis of Dimethyl Ether and Alternative Fuels in the Liquid Phase from Coal-Derived Syngas'' experimental evaluations of the one-step synthesis of alternative fuels were carried out. The objective of this work was to develop novel processes for converting coal-derived syngas to fuels or fuel additives. Building on a technology base acquired during the development of the Liquid Phase Methanol (LPMEOH) process, this work focused on the development of slurry reactor based processes. The experimental investigations, which involved bench-scale reactor studies, focused primarily on three areas: (1) One-step, slurry-phase syngas conversion to hydrocarbons or methanol/hydrocarbonmore » mixtures using a mixture of methanol synthesis catalyst and methanol conversion catalyst in the same slurry reactor. (2) Slurry-phase conversion of syngas to mixed alcohols using various catalysts. (3) One-step, slurry-phase syngas conversion to mixed ethers using a mixture of mixed alcohols synthesis catalyst and dehydration catalyst in the same slurry reactor. The experimental results indicate that, of the three types of processes investigated, slurry phase conversion of syngas to mixed alcohols shows the most promise for further process development. Evaluations of various mixed alcohols catalysts show that a cesium-promoted Cu/ZnO/Al[sub 2]O[sub 3] methanol synthesis catalyst, developed in Air Products' laboratories, has the highest performance in terms of rate and selectivity for C[sub 2+]-alcohols. In fact, once-through conversion at industrially practical reaction conditions yielded a mixed alcohols product potentially suitable for direct gasoline blending. Moreover, an additional attractive aspect of this catalyst is its high selectivity for branched alcohols, potential precursors to iso-olefins for use in etherification.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Underwood, R.P.

As part of the DOE-sponsored contract ``Synthesis of Dimethyl Ether and Alternative Fuels in the Liquid Phase from Coal-Derived Syngas`` experimental evaluations of the one-step synthesis of alternative fuels were carried out. The objective of this work was to develop novel processes for converting coal-derived syngas to fuels or fuel additives. Building on a technology base acquired during the development of the Liquid Phase Methanol (LPMEOH) process, this work focused on the development of slurry reactor based processes. The experimental investigations, which involved bench-scale reactor studies, focused primarily on three areas: (1) One-step, slurry-phase syngas conversion to hydrocarbons or methanol/hydrocarbonmore » mixtures using a mixture of methanol synthesis catalyst and methanol conversion catalyst in the same slurry reactor. (2) Slurry-phase conversion of syngas to mixed alcohols using various catalysts. (3) One-step, slurry-phase syngas conversion to mixed ethers using a mixture of mixed alcohols synthesis catalyst and dehydration catalyst in the same slurry reactor. The experimental results indicate that, of the three types of processes investigated, slurry phase conversion of syngas to mixed alcohols shows the most promise for further process development. Evaluations of various mixed alcohols catalysts show that a cesium-promoted Cu/ZnO/Al{sub 2}O{sub 3} methanol synthesis catalyst, developed in Air Products` laboratories, has the highest performance in terms of rate and selectivity for C{sub 2+}-alcohols. In fact, once-through conversion at industrially practical reaction conditions yielded a mixed alcohols product potentially suitable for direct gasoline blending. Moreover, an additional attractive aspect of this catalyst is its high selectivity for branched alcohols, potential precursors to iso-olefins for use in etherification.« less

Solvent effects on quantitative analysis of brominated flame retardants with Soxhlet extraction.

PubMed

Zhong, Yin; Li, Dan; Zhu, Xifen; Huang, Weilin; Peng, Ping'an

2017-05-18

Reliable quantifications of brominated flame retardants (BFRs) not only ensure compliance with laws and regulations on the use of BFRs in commercial products, but also is key for accurate risk assessments of BFRs. Acetone is a common solvent widely used in the analytical procedure of BFRs, but our recent study found that acetone can react with some BFRs. It is highly likely that such reactions can negatively affect the quantifications of BFRs in environmental samples. In this study, the effects of acetone on the extraction yields of three representative BFRs [i.e., decabrominated diphenyl ether (decaBDE), hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA)] were evaluated in the Soxhlet extraction (SE) system. The results showed that acetone-based SE procedure had no measureable effect for the recovery efficiencies of decaBDE but could substantially lower the extraction yields for both TBBPA and HBCD. After 24 h of extraction, the recovery efficiencies of TBBPA and HBCD by SE were 93 and 78% with acetone, 47 and 70% with 3:1 acetone:n-hexane, and 82 and 94% with 1:1 acetone:n-hexane, respectively. After 72 h of extraction, the extraction efficiencies of TBBPA and HBCD decreased to 68 and 55% with acetone, 0 and 5% with 3:1 acetone/n-hexane mixtures, and 0 and 13% with 1:1 acetone/n-hexane mixtures, respectively. The study suggested that the use of acetone alone or acetone-based mixtures should be restricted in the quantitative analysis of HBCD and TBBPA. We further evaluated nine alternative solvents for the extraction of the three BFRs. The result showed that diethyl ether might be reactive with HBCD and may not be considered as the alternative to acetone used solvents for the extraction of HBCD.

Method for producing microcomposite powders using a soap solution

DOEpatents

Maginnis, Michael A.; Robinson, David A.

1996-01-01

A method for producing microcomposite powders for use in superconducting and non-superconducting applications. A particular method to produce microcomposite powders for use in superconducting applications includes the steps of: (a) preparing a solution including ammonium soap; (b) dissolving a preselected amount of a soluble metallic such as silver nitrate in the solution including ammonium soap to form a first solution; (c) adding a primary phase material such as a single phase YBC superconducting material in particle form to the first solution; (d) preparing a second solution formed from a mixture of a weak acid and an alkyl-mono-ether; (e) adding the second solution to the first solution to form a resultant mixture; (f) allowing the resultant mixture to set until the resultant mixture begins to cloud and thicken into a gel precipitating around individual particles of the primary phase material; (g) thereafter drying the resultant mixture to form a YBC superconducting material/silver nitrate precursor powder; and (h) calcining the YBC superconducting material/silver nitrate precursor powder to convert the silver nitrate to silver and thereby form a YBC/silver microcomposite powder wherein the silver is substantially uniformly dispersed in the matrix of the YBC material.

Exposure assessment of ETBE in gas station workers and gasoline tanker truck drivers.

PubMed

Eitaki, Yoko; Kawai, Toshio; Omae, Kazuyuki

2011-01-01

In order to measure occupational exposure concentrations of ethyl tertiary-butyl ether (ETBE), we developed a diffusive sampling method for monitoring ETBE and performed an ETBE exposure assessment. The applicability of diffusive samplers was examined by exposing the samplers to ETBE vapor in test chambers. The personal exposure levels of workers and airborne concentrations were measured at 4 gas stations. The ETBE sampling rate for the diffusive samplers (VOC-SD, Sigma-Aldrich Japan) was 25.04 ml/min (25°C). Compared with the active sampling method, the diffusive samplers could be used for short-term measurements and in environments containing a mixture of organic solvents. The geometric mean (GM) of TWA-8h ETBE was 0.08 ppm (0.02-0.28 ppm) in 28 gas station workers and 0.04 ppm (0.01-0.21 ppm) in 2 gasoline tanker truck drivers. With regard to ETBE airborne concentrations, the GM was 4.12 ppm (0.93-8.71 ppm) at the handles of hanging pumps but dropped to less than 0.01 ppm (less than 0.01-0.01 ppm) at the side of a public road. The diffusive sampling method can be used for the measurement of occupational ETBE exposure. The threshold limit of TLV-TWA 5 ppm recommended by the ACGIH was not exceeded in any of the workers in this study.

Structural wood panels with improved fire resistance

NASA Technical Reports Server (NTRS)

Sawko, P. M. (Inventor)

1980-01-01

Structural wood paneling or other molded wood compositions consisting of finely divided wood chips, flour, or strands are bound together and hot pressed with a modified novolac resin which is the cured product of a prepolymer made from an aralkyl ether or halide with a phenol and a hardening agent such as hexamethylene tetramine. The fire resistance of these articles is further improved by incorporating in the binder certain inorganic fillers, especially a mixture of ammonium oxalate and ammonium phosphate.

SALICYLATE PROCESS FOR THORIUM SEPARATION FROM RARE EARTHS

DOEpatents

Cowan, G.A.

1959-08-25

The separation of thorium from rare earths is accomplished by forming an aqueous solution of salts of thorium and rare earths and sufficient acetate buffer to provide a pH of between 2 and 5, adding an ammonium salicylate to the aqueous buffered solution, contacting the resultant solution with a substantially water-immiscible organic solvent mixture of an ether and an ester, and separating the solvent extract phase containing thorium salicylate from the aqueous phase containing the rare earths.

Phase behavior of the mixtures of poly(oxyethylene) (10) stearyl ether (Brij-76), 1-butanol, isooctane, and mixed polar solvents II. Water and ethylene glycol (EG) or tetraethylene glycol (TEG).

PubMed

Nandy, Debdurlav; Mitra, Rajib K; Paul, Bidyut K

2007-06-01

The phase diagrams of the pseudo-quaternary systems poly(oxyethylene) (10) stearyl ether (Brij-76)/1-butanol/isooctane/water (with equal amounts of oil and water in the presence of two nonaqueous polar solvents (NPS), ethylene glycol (EG), and tetraethylene glycol (TEG)), have been constructed at 30 degrees C. Regular fish-tail diagrams were obtained up to psi (weight fraction of EG or TEG in the mixture of polar solvents) equal to 0.5, confirming the establishment of hydrophile-lipophile balance (HLB) of the systems. The maximum solubilization capacity passed through a minimum at psi=0.2. No HLB was obtained at higher psi. The usual fish-tail diagrams were also obtained in temperature-induced phase mapping at fixed W(1) (weight fraction of 1-butanol in total amphiphile). Solubilization capacity and HLB temperature (T(HLB)) decreased with increasing psi at a fixed W(1), the effect being more pronounced for TEG than EG. A correlation between HLB temperature (T(HLB)) and HLB number (N(HLB)) of mixed amphiphiles (Brij-76+Bu) in pseudo-quaternary systems (in the presence of water and partial substitution of water with both NPS) has been established. The novelty of the work with respect to possible applications has been discussed.

Preparation of siRNA encapsulated nanoliposomes suitable for siRNA delivery by simply discontinuous mixing.

PubMed

Mokhtarieh, Amir Abbas; Lee, Jieun; Kim, Semi; Lee, Myung Kyu

2018-06-01

Previously a scalable and extrusion-free method has been developed for efficient liposomal encapsulation of DNA by twice stepwise mixing of lipids in ethanol and DNA solution using T-shape mixing chamber. In this study, we prepared nanoliposomes encapsulating siRNA by simply discontinuous mixing of lipids in ethanol/ether/water mixture and acidic siRNA solution without use of special equipment. The simple mixing siRNA/liposomal particles (siRNA/SMLs) prepared using ethanol/ether/water (3:1:1) mixture showed 120.4 ± 20.2 nm particle size, 0.174 ± 0.033 polydispersity and 86.5 ± 2.76% siRNA encapsulation rate. In addition, the SMLs almost completely protected the encapsulated siRNA from RNase A digestion. Coupling of anti-human epidermal growth factor receptor (EGFR) Fab' to siRNA/SMLs enhanced EGFR-specific cell penetration of SMLs and induced siRNA dependent gene silencing. Unexpectedly, the Cy5.5-labeled Fab' showed almost no in vivo targeting to the xenografted A549 tumors in SCID-NOD mice. However, multiple injection of the unmodified siRNA/SMLs accumulated in the tumors and induced siRNA-dependent in vivo gene silencing. These results demonstrate that the siRNA/SMLs can be used as a siRNA delivery tool for gene therapy. Copyright © 2018 Elsevier B.V. All rights reserved.

Factorial-design optimization of gas chromatographic analysis of tetrabrominated to decabrominated diphenyl ethers. Application to domestic dust.

PubMed

Regueiro, Jorge; Llompart, Maria; Garcia-Jares, Carmen; Cela, Rafael

2007-07-01

Gas chromatographic analysis of polybrominated diphenyl ethers (PBDEs) has been evaluated in an attempt to achieve better control of the separation process, especially for highly substituted congeners. Use of a narrow-bore capillary column enabled adequate determination of tetra, penta, hexa, hepta, octa, nona and decaBDE congeners in only one chromatographic run while maintaining resolution power similar to that of conventional columns. A micro electron-capture detector (GC-microECD) was used. Chromatographic conditions were optimized by multifactorial experimental design, with the objective of obtaining not only high sensitivity but also good precision. In this way two different approaches to maximizing response and minimizing variability were tested, and are fully discussed. These optimum chromatographic conditions were then used to determine PBDEs extracted from domestic dust samples by microwave-assisted solvent extraction (MASE). Quantitative recovery (90-108%) was achieved for all the PBDEs and method precision (RSD < 13%) was satisfactory. Accuracy was tested by use of the standard reference material SRM 2585, and sub-ng g(-1) limits of detection were obtained for all compounds except BDE-209 (1.44 ng g(-1)). Finally, several samples of house dust were analysed by use of the proposed method and all the target PBDEs were detected in all the samples. BDE-209 was the predominant congener. Amounts varied from 58 to 1615 ng g(-1) and the average contribution to the total PBDE burden of 52%. The main congeners of the octaBDE mixture (BDE-183, BDE-197, BDE-207 and BDE-196) also made an important contribution (29%) to the total. These are the first data about the presence of these compounds in European house-dust samples. Finally, the sum of the main congeners in the pentaBDE commercial mixture (BDE-47, BDE-99, and BDE-100) contributed 14% to the total. Figure Polybrominated diphenyl ethers in House Dust.

Drop-in substitute for dichlorodifluoromethane refrigerant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goble, G.H.

1993-06-01

A method for producing refrigeration in a refrigeration system designed for a dichlorodifluoromethane refrigerant is described, comprising drop-in substituting for said dichlorodifluoromethane a ternary mixture of about 2 to 20 weight percent isobutane, about 21 to 51 weight percent 1-chloro-1,1-difluoroethane, and about 41 to 71 weight percent chlorodifluoromethane, with the weight percentages of said components being weight percentages of the overall mixture; condensing said ternary mixture; and thereafter evaporating said ternary mixture in the vicinity of a body to be cooled.

Novel and high volume use flame retardants in US couches reflective of the 2005 PentaBDE phase out.

PubMed

Stapleton, Heather M; Sharma, Smriti; Getzinger, Gordon; Ferguson, P Lee; Gabriel, Michelle; Webster, Thomas F; Blum, Arlene

2012-12-18

California's furniture flammability standard Technical Bulletin 117 (TB 117) is believed to be a major driver of chemical flame retardant (FR) use in residential furniture in the United States. With the phase-out of the polybrominated diphenyl ether (PBDE) FR mixture PentaBDE in 2005, alternative FRs are increasingly being used to meet TB 117; however, it was unclear which chemicals were being used and how frequently. To address this data gap, we collected and analyzed 102 samples of polyurethane foam from residential couches purchased in the United States from 1985 to 2010. Overall, we detected chemical flame retardants in 85% of the couches. In samples purchased prior to 2005 (n = 41) PBDEs associated with the PentaBDE mixture including BDEs 47, 99, and 100 (PentaBDE) were the most common FR detected (39%), followed by tris(1,3-dichloroisopropyl) phosphate (TDCPP; 24%), which is a suspected human carcinogen. In samples purchased in 2005 or later (n = 61) the most common FRs detected were TDCPP (52%) and components associated with the Firemaster550 (FM 550) mixture (18%). Since the 2005 phase-out of PentaBDE, the use of TDCPP increased significantly. In addition, a mixture of nonhalogenated organophosphate FRs that included triphenyl phosphate (TPP), tris(4-butylphenyl) phosphate (TBPP), and a mix of butylphenyl phosphate isomers were observed in 13% of the couch samples purchased in 2005 or later. Overall the prevalence of flame retardants (and PentaBDE) was higher in couches bought in California compared to elsewhere, although the difference was not quite significant (p = 0.054 for PentaBDE). The difference was greater before 2005 than after, suggesting that TB 117 is becoming a de facto standard across the U.S. We determined that the presence of a TB 117 label did predict the presence of a FR; however, lack of a label did not predict the absence of a flame retardant. Following the PentaBDE phase out, we also found an increased number of flame retardants on the market. Given these results, and the potential for human exposure to FRs, health studies should be conducted on the types of FRs identified here.

Thermal diffusion behavior of nonionic surfactants in water.

PubMed

Ning, Hui; Kita, Rio; Kriegs, Hartmut; Luettmer-Strathmann, Jutta; Wiegand, Simone

2006-06-08

We studied the thermal diffusion behavior of hexaethylene glycol monododecyl ether (C12E6) in water by means of thermal diffusion forced Rayleigh scattering (TDFRS) and determined Soret coefficients, thermal diffusion coefficients, and diffusion constants at different temperatures and concentrations. At low surfactant concentrations, the measured Soret coefficient is positive, which implies that surfactant micelles move toward the cold region in a temperature gradient. For C12E6/water at a high surfactant concentration of w1 = 90 wt % and a temperature of T = 25 degrees C, however, a negative Soret coefficient S(T) was observed. Because the concentration part of the TDFRS diffraction signal for binary systems is expected to consist of a single mode, we were surprised to find a second, slow mode for C12E6/water system in a certain temperature and concentration range. To clarify the origin of this second mode, we investigated also, tetraethylene glycol monohexyl ether (C6E4), tetraethylene glycol monooctyl ether (C8E4), pentaethylene glycol monododecyl ether (C12E5), and octaethylene glycol monohexadecyl ether (C16E8) and compared the results with the previous results for octaethylene glycol monodecyl ether (C10E8). Except for C6E4 and C10E8, a second slow mode was observed in all systems usually for state points close to the phase boundary. The diffusion coefficient and Soret coefficient derived from the fast mode can be identified as the typical mutual diffusion and Soret coefficients of the micellar solutions and compare well with the independently determined diffusion coefficients in a dynamic light scattering experiment. Experiments with added salt show that the slow mode is suppressed by the addition of w(NaCl) = 0.02 mol/L sodium chloride. This suggests that the slow mode is related to the small amount of absorbing ionic dye, less than 10(-5) by weight, which is added in TDFRS experiments to create a temperature grating. The origin of the slow mode of the TDFRS signal will be tentatively interpreted in terms of a ternary mixture of neutral micelles, dye-charged micelles, and water.

Interactions between selected bile salts and Triton X-100 or sodium lauryl ether sulfate.

PubMed

Cirin, Dejan M; Poša, Mihalj M; Krstonošić, Veljko S

2011-12-29

In order to develop colloidal drug carriers with desired properties, it is important to determine physico-chemical characteristics of these systems. Bile salt mixed micelles are extensively studied as novel drug delivery systems. The objective of the present investigation is to develop and characterize mixed micelles of nonionic (Triton X-100) or anionic (sodium lauryl ether sulfate) surfactant having oxyethylene groups in the polar head and following bile salts: cholate, deoxycholate and 7-oxodeoxycholate. The micellization behaviour of binary anionic-nonionic and anionic-anionic surfactant mixtures was investigated by conductivity and surface tension measurements. The results of the study have been analyzed using Clint's, Rubingh's, and Motomura's theories for mixed binary systems. The negative values of the interaction parameter indicate synergism between micelle building units. It was noticed that Triton X-100 and sodium lauryl ether sulfate generate the weakest synergistic interactions with sodium deoxycholate, while 7-oxodeoxycholate creates the strongest attractive interaction with investigated co-surfactants. It was concluded that increased synergistic interactions can be attributed to the larger number of hydrophilic groups at α side of the bile salts. Additionally, 7-oxo group of 7-oxodeoxycholate enhance attractive interactions with selected co-surfactants more than 7-hydroxyl group of sodium cholate.

Interactions between selected bile salts and Triton X-100 or sodium lauryl ether sulfate

PubMed Central

2011-01-01

Background In order to develop colloidal drug carriers with desired properties, it is important to determine physico-chemical characteristics of these systems. Bile salt mixed micelles are extensively studied as novel drug delivery systems. The objective of the present investigation is to develop and characterize mixed micelles of nonionic (Triton X-100) or anionic (sodium lauryl ether sulfate) surfactant having oxyethylene groups in the polar head and following bile salts: cholate, deoxycholate and 7-oxodeoxycholate. Results The micellization behaviour of binary anionic-nonionic and anionic-anionic surfactant mixtures was investigated by conductivity and surface tension measurements. The results of the study have been analyzed using Clint's, Rubingh's, and Motomura's theories for mixed binary systems. The negative values of the interaction parameter indicate synergism between micelle building units. It was noticed that Triton X-100 and sodium lauryl ether sulfate generate the weakest synergistic interactions with sodium deoxycholate, while 7-oxodeoxycholate creates the strongest attractive interaction with investigated co-surfactants. Conclusion It was concluded that increased synergistic interactions can be attributed to the larger number of hydrophilic groups at α side of the bile salts. Additionally, 7-oxo group of 7-oxodeoxycholate enhance attractive interactions with selected co-surfactants more than 7-hydroxyl group of sodium cholate. PMID:22206681

Anthropogenic and Naturally Produced Brominated Phenols in Pet Blood and Pet Food in Japan.

PubMed

Mizukawa, Hazuki; Nomiyama, Kei; Nakatsu, Susumu; Yamamoto, Miyuki; Ishizuka, Mayumi; Ikenaka, Yoshinori; Nakayama, Shouta M M; Tanabe, Shinsuke

2017-10-03

Present study determined concentrations and residue patterns of bromophenols (BPhs) in whole blood samples of pet cats and pet dogs collected from veterinary hospitals in Japan. BPhs concentrations were higher in cat blood than in dog blood, with statistically insignificant differences (p = 0.07). Among the congeners, 2,4,6-tribromophenol (TBPh) constituted the majority of BPhs (>90%) detected in both species. Analysis of commercial pet food to estimate exposure routes showed that the most abundant congener in all pet food samples was 2,4,6-TBPh, accounting for >99% of total BPhs. This profile is quite similar to the blood samples of the pets, suggesting that diet might be an important exposure route for BPhs in pets. After incubation in polybrominated diphenyl ether (PBDE) mixtures (BDE-47, BDE-99 and BDE-209), 2,4,5-TBPh was found in dog liver microsomes but not in cat liver microsomes, implying species-specific metabolic capacities for PBDEs. Formation of 2,4,5-TBPh occurred by hydroxylation at the 1' carbon atom of the ether bond of BDE-99 is similar to human study reported previously. Hydroxylated PBDEs were not detected in cats or dogs; therefore, diphenyl ether bond cleavage of PBDEs can also be an important metabolic pathway for BPhs formation in cats and dogs.

Organic monolith frits encased in polyether ether ketone tubing with improved durability for liquid chromatography.

PubMed

Park, Sin Young; Cheong, Won Jo

2015-09-01

This study introduces a preparation method for polymer-encased monolith frits with improved durability for liquid chromatography columns. The inner surface of the polyether ether ketone tubing is pretreated with sulfuric acid in the presence of catalysts (vanadium oxide and sodium sulfate). The tubing was rinsed with water and acetone, flushed with nitrogen, and treated with glycidyl methacrylate. After washing, the monolith reaction mixture composed of lauryl methacrylate, ethylene glycol dimethacrylate, initiator, and porogenic solvent was filled in the tubing and subjected to in situ polymerization. The tubing was cut into thin slices and used as frits for microcolumns. To check their durability, the frit slices were placed in a vial and a heavy impact was applied on the vial by a vortex mixer for various periods. The frits made in the presence of catalysts were found to be more durable than those made without catalysts. Furthermore, when the monolith-incorporated tubing was used as a chromatography column, the column prepared in the presence of catalysts resulted in a better separation efficiency. The separation performance of the columns installed with the polyether ether ketone encased monolith frits was comparable to that of the columns installed with the commercial stainless-steel screen frits. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sterol Alkyl Ethers in Immature Callovian (Middle Jurassic) Sediments of Pas de Calais and Normandy (France): Environmental Constraints on their Potential Origins.

NASA Astrophysics Data System (ADS)

Kenig, F. P. H.

2017-12-01

Steryl alkyl ethers (SAEs), steroids with C8-C12 alkyl ether substituent at C3have only been reported in a limited number of studies since their first identification in modern diatomaceous ooze (Boon and de Leeuw, 1979 Mar. Chem. 7, 117-132). These compounds were identified in Holocene to Eocene sediments, but only once in the Cretaceous, in the Valanginian sediments of Shasky Rise (Brassell, 2009; Palaeo Palaeo Palaeo 282, 45-57). The origin of these compounds remains unclear, though they have been proposed to be associated with diatoms and biologically productive environments and cold water. Here we report the occurrence of SAEs in Callovian (Middle Jurassic), thermally immature sediments of the Marnes d'Argences near Caen (Normandy, France) and near Le Wast (Pas de Calais, France), extanding their geological occurrence by 28 million years. These marls contain C36 to C41 SAEs with C9 or C10 alkyl moieties. The steroid moieties (C27 to C31) are saturated, unsaturated (at C5 or C22), or di-unsaturated (at C5 and C22). Some of the samples collected near Le Wast contain only 4-methyl substituted C27, C28 and C29 steroid moieties as well as steroid moieties typical of dinoflagellates such 4,23,24-trimethylsteroids saturated and unsaturated at C22, and diatoms such as 4-desmethyl-23,24-dimethyl-steroid. The origin of SAEs will be discussed in view of their novel identification in Jurassic sediments and considering the environment of deposition of the Marnes d'Argences and comparison with their stratigraphic equivalent in England (Oxford Clay) and Eastern France where none of these compounds were observed.

Assessing the combined influence of TOC and black carbon in soil-air partitioning of PBDEs and DPs from the Indus River Basin, Pakistan.

PubMed

Ali, Usman; Mahmood, Adeel; Syed, Jabir Hussain; Li, Jun; Zhang, Gan; Katsoyiannis, Athanasios; Jones, Kevin C; Malik, Riffat Naseem

2015-06-01

Levels of polybrominated diphenyl ethers (PBDEs) and dechlorane plus (DPs) were investigated in the Indus River Basin from Pakistan. Concentrations of ∑PBDEs and ∑DPs were ranged between 0.05 and 2.38 and 0.002-0.53 ng g(-1) in the surface soils while 1.43-22.1 and 0.19-7.59 pg m(-3) in the passive air samples, respectively. Black carbon (fBC) and total organic carbon (fTOC) fractions were also measured and ranged between 0.73 and 1.75 and 0.04-0.2%, respectively. The statistical analysis revealed strong influence of fBC than fTOC on the distribution of PBDEs and DPs in the Indus River Basin soils. BDE's congener profile suggested the input of penta-bromodiphenylether (DE-71) commercial formulation in the study area. Soil-air partitioning of PBDEs were investigated by employing octanol-air partition coefficients (KOA) and black carbon-air partition coefficients (KBC-A). The results of both models suggested the combined influence of total organic carbon (absorption) and black carbon (adsorption) in the studied area. Copyright © 2015 Elsevier Ltd. All rights reserved.

Brominated Flame Retardants in Sediments of Four Coastal Lagoons of Yucatan, Mexico.

PubMed

Valenzuela-Sánchez, I S; Gold-Bouchot, G; Hernández-Núñez, E; Barrientos-Medina, R C; Garza-Gisholt, E; Zapata-Pérez, O

2018-05-02

We examined the sediments of four coastal lagoons (Ria Lagartos, Bocas de Dzilam, Laguna de Chelem and Ria Celestun) from the state of Yucatan, Mexico, for three widely used commercial polybrominated diphenyl ethers formulations (penta-, octa- and deca-BDE). The most commonly found congeners in all four lagoons were BDEs 47, 99 and 100 (all in the penta-BDE formulation) and BDE209 (deca-BDE formulation). The greatest variety and highest concentrations of brominated flame retardants were found in Ria Lagartos, which also showed the highest BDE 100 concentration (24.129 ng/g). Hexabromocyclododecane was found in all lagoons, but at lower concentrations than those of the various polybrominated diphenyl ethers. Dispersal routes of these compounds are discussed, such as a ring of sinkholes (cenotes) adjacent to the lagoons. Moreover, electronic waste is a serious problem because municipal landfills have been the primary disposal method for these wastes and therefore represent a reservoir of brominated fire retardants.

Activation of C-O and C-C bonds and formation of novel HAlOH-ether complexes: an EPR study of the reaction of ground-state Al atoms with methylethyl ether and diethyl ether.

PubMed

Brunet, François D; Feola, Julie C; Joly, Helen A

2012-03-15

Reaction mixtures, containing Al atoms and methylethyl ether (MEE) or diethyl ether (DEE) in an adamantane matrix, were prepared with the aid of a metal-atom reactor known as a rotating cryostat. The EPR spectra of the resulting products were recorded from 77-260 K, at 10 K intervals. Al atoms were found to insert into methyl-O, ethyl-O, and C-C bonds to form CH(3)AlOCH(2)CH(3), CH(3)OAlCH(2)CH(3), and CH(3)OCH(2)AlCH(3), respectively, in the case of MEE while DEE produced CH(3)CH(2)AlOCH(2)CH(3) and CH(3)AlCH(2)OCH(2)CH(3), respectively. From the intensity of the transition lines attributed to the Al atom C-O insertion products of MEE, insertion into the methyl-O bond is preferred. The Al hyperfine interaction (hfi) extracted from the EPR spectra of the C-O insertion products was greater than that of the C-C insertion products, that is, 5.4% greater for the DEE system and 7% greater for the MEE system. The increase in Al hfi is thought to arise from the increased electron-withdrawing ability of the substituents bonded to Al. Besides HAlOH, resulting from the reaction of Al atoms with adventitious water, novel mixed HAlOH:MEE and HAlOH:DEE complexes were identified with the aid of isotopic studies involving H(2)(17)O and D(2)O. The Al and H hfi of HAlOH were found to decrease upon complex formation. These findings are consistent with the nuclear hfi calculated using a density functional theory (DFT) method with close agreement between theory and experiment occurring at the B3LYP level using a 6-311+G(2df,p) basis set.

Isolation of homoleptic platinum oxyanionic complexes with doubly protonated diazacrown cation

NASA Astrophysics Data System (ADS)

Vasilchenko, Danila; Tkachev, Sergey; Baidina, Iraida; Romanenko, Galina; Korenev, Sergey

2017-02-01

Doubly protonated diazacrown ether cation (1,4,10,13-tetraoxa-7,16-diazoniacyclooctadecane DCH22+) was used for the efficient isolation of the homoleptic platinum complexes [Pt(NO3)6]2- and [Pt(C2O4)2]2- to crystalline solid phases from solutions containing mixtures of related platinum complexes. DCH22+ molecules in nitric acid solution were shown to prevent the condensation of mononuclear [Pt(H2O)n(NO3)6-n]n-2 species.

Boron determination in steels by Inductively-Coupled Plasma spectometry (ICP)

NASA Technical Reports Server (NTRS)

Coedo, A. G.; Lopez, M. T. D.

1986-01-01

The sample is treated with 5N H2SO4 followed by concentrated HNO3 and the diluted mixture is filtered. Soluble B is determined in the filtrate by Inductively-Coupled Plasma (ICP) spectrometry after addition HCl and extraction of Fe with ethyl-ether. The residue is fused with Na2CO3 and, after treatment with HCl, the insoluble B is determined by ICP spectrometry as before. The method permits determination of ppm amounts of B in steel.

Lithiated imines: solvent-dependent aggregate structures and mechanisms of alkylation.

PubMed

Zuend, Stephan J; Ramirez, Antonio; Lobkovsky, Emil; Collum, David B

2006-05-03

We describe efforts to understand the structure and reactivity of lithiated cyclohexanone N-cyclohexylimine. The lithioimine affords complex solvent-dependent distributions of monomers, dimers, and trimers in a number of ethereal solvents. Careful selection of solvent provides exclusively monosolvated dimers. Rate studies on the C-alkylations reveal chronic mixtures of monomer- and dimer-based pathways. We explore the factors influencing reactants and alkylation transition structures and the marked differences between lithioimines and isostructural lithium dialkylamides with the aid of density functional theory calculations.

Alkylation of phenol by alcohols in the presence of aluminum phenolate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koshchii, V.A.; Kozlikovskii, Ya.B.; Matyusha, A.A.

1988-12-20

The reaction of phenol with alcohols in the presence of aluminum phenolate leads to a mixture of 2- and 4-alkylphenols, of which the former predominate in the case of benzyl, tert-butyl, and cyclohexyl alcohols, and the latter in the case of dimethylphenyl- and diphenylmethylcarbinols. Only triphenyl(4-hydroxyphenyl)-methane is formed during the alkylation of phenol by triphenylcarbinol. In individual experiments the formation of small amounts of alkyl phenyl ethers and 2,6-dialkylphenols was observed.

Method for absorbing hydrogen using an oxidation resisant organic hydrogen getter

DOEpatents

Shepodd, Timothy J [Livermore, CA; Buffleben, George M [Tracy, CA

2009-02-03

A composition for removing hydrogen from an atmosphere, comprising a mixture of a polyphenyl ether and a hydrogenation catalyst, preferably a precious metal catalyst, and most preferably platinum, is disclosed. This composition is stable in the presence of oxygen, will not polymerize or degrade upon exposure to temperatures in excess of 200.degree. C., or prolonged exposure to temperatures in the range of 100-300.degree. C. Moreover, these novel hydrogen getter materials can be used to efficiently remove hydrogen from mixtures of hydrogen/inert gas (e.g., He, Ar, N.sub.2), hydrogen/ammonia atmospheres, such as may be encountered in heat exchangers, and hydrogen/carbon dioxide atmospheres. Water vapor and common atmospheric gases have no adverse effect on the ability of these getter materials to absorb hydrogen.

Off-line real-time FTIR analysis of a process step in imipenem production

NASA Astrophysics Data System (ADS)

Boaz, Jhansi R.; Thomas, Scott M.; Meyerhoffer, Steven M.; Staskiewicz, Steven J.; Lynch, Joseph E.; Egan, Richard S.; Ellison, Dean K.

1992-08-01

We have developed an FT-IR method, using a Spectra-Tech Monit-IR 400 systems, to monitor off-line the completion of a reaction in real-time. The reaction is moisture-sensitive and analysis by more conventional methods (normal-phase HPLC) is difficult to reproduce. The FT-IR method is based on the shift of a diazo band when a conjugated beta-diketone is transformed into a silyl enol ether during the reaction. The reaction mixture is examined directly by IR and does not require sample workup. Data acquisition time is less than one minute. The method has been validated for specificity, precision and accuracy. The results obtained by the FT-IR method for known mixtures and in-process samples compare favorably with those from a normal-phase HPLC method.

Formation of hollow silica nanospheres by reverse microemulsion

NASA Astrophysics Data System (ADS)

Lin, Cheng-Han; Chang, Jen-Hsuan; Yeh, Yi-Qi; Wu, Si-Han; Liu, Yi-Hsin; Mou, Chung-Yuan

2015-05-01

Uniform hollow silica nanospheres (HSNs) synthesized with reverse microemulsion have great application potential as nanoreactors because enzymes or nanocatalysts can be easily encapsulated de novo in synthesis. Water-in-oil (w/o) reverse microemulsions comprising the polymeric surfactant polyoxyethylene (5) isooctylphenyl ether (Igepal CA-520), ammonia and water in a continuous oil phase (alkanes) coalesce into size-tunable silica nanoparticles via diffusion aggregation after the introduction of silica precursors. Here, we elucidate in detail the growth mechanism for silica nanoparticles via nucleation of ammonium-catalyzed silica oligomers from tetraethylorthosilicate (TEOS) and nanoporous aminopropyltrimethoxy silane (APTS) in the reverse microemulsion system. The formation pathway was studied in situ with small-angle X-ray scattering (SAXS). We find a four-stage process showing a sigmoidal growth behavior in time with a crossover from the induction period, early nucleation stage, coalescence growth and a final slowing down of growth. Various characterizations (TEM, N2 isotherm, dynamic light scattering, zeta potential, NMR, elemental analysis) reveal the diameters, scattering length density (SLD), mesoporosity, surface potentials and chemical compositions of the HSNs. Oil phases of alkanes with different alkyl chains are systematically employed to tune the sizes of HSNs by varying oil molar volumes, co-solvent amounts or surfactant mixture ratios. Silica condensation is incomplete in the core region, with the silica source of TEOS and APTS leading to the hollow silica nanosphere after etching with warm water.Uniform hollow silica nanospheres (HSNs) synthesized with reverse microemulsion have great application potential as nanoreactors because enzymes or nanocatalysts can be easily encapsulated de novo in synthesis. Water-in-oil (w/o) reverse microemulsions comprising the polymeric surfactant polyoxyethylene (5) isooctylphenyl ether (Igepal CA-520), ammonia and water in a continuous oil phase (alkanes) coalesce into size-tunable silica nanoparticles via diffusion aggregation after the introduction of silica precursors. Here, we elucidate in detail the growth mechanism for silica nanoparticles via nucleation of ammonium-catalyzed silica oligomers from tetraethylorthosilicate (TEOS) and nanoporous aminopropyltrimethoxy silane (APTS) in the reverse microemulsion system. The formation pathway was studied in situ with small-angle X-ray scattering (SAXS). We find a four-stage process showing a sigmoidal growth behavior in time with a crossover from the induction period, early nucleation stage, coalescence growth and a final slowing down of growth. Various characterizations (TEM, N2 isotherm, dynamic light scattering, zeta potential, NMR, elemental analysis) reveal the diameters, scattering length density (SLD), mesoporosity, surface potentials and chemical compositions of the HSNs. Oil phases of alkanes with different alkyl chains are systematically employed to tune the sizes of HSNs by varying oil molar volumes, co-solvent amounts or surfactant mixture ratios. Silica condensation is incomplete in the core region, with the silica source of TEOS and APTS leading to the hollow silica nanosphere after etching with warm water. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr01395j

In vitro toxicities of experimental jet fuel system ice-inhibiting agents.

PubMed

Geiss, K T; Frazier, J M

2001-07-02

One research emphasis within the Department of Defense has been to seek the replacement of operational compounds with alternatives that pose less potential risk to human and ecological systems. Alternatives to glycol ethers, such as diethylene glycol monomethyl ether (M-DE), were investigated for use as jet fuel system ice-inhibiting agents (FSIIs). This group of chemicals includes three derivatives of 1,3-dioxolane-4-methanol (M-1, M-2, and M-3) and a 1,3-dioxane (M-27). In addition, M-DE was evaluated as a reference compound. Our approach was to implement an in vitro test battery based on primary rat hepatocyte cultures to perform initial toxicity evaluations. Hepatocytes were exposed to experimental chemicals (0, 0.001, 0.01, 0.1, 1, 10 mM dosages) for periods up to 24 h. Samples were assayed for lactate dehydrogenase (LDH) release, MTT dye reduction activity, glutathione level, and rate of protein synthesis as indicators of toxicity. Of the compounds tested, M-1, especially at the 10-mM dose, appeared to be more potent than the other chemicals, as measured by these toxicity assays. M-DE, the current FSII, elicited little response in the toxicity assays. Although some variations in toxicity were observed at the 10-mM dose, the in vitro toxicities of the chemicals tested (except for M-1) were not considerably greater than that of M-DE.

Removal of phenol from aqueous solution using polymer inclusion membrane based on mixture of CTA and CA

NASA Astrophysics Data System (ADS)

Benosmane, Nadjib; Boutemeur, Baya; Hamdi, Safouane M.; Hamdi, Maamar

2018-03-01

Nowadays, there are increasingly stringent regulations requiring more and more treatment of industrial effluents to generate product waters which could be easily reused or disposed of to the environment without any harmful effects. In the present work, the removal of phenol from aqueous solution across polymer inclusion membrane (PIM), based on mixture of cellulose triacetate and cellulose acetate as support (75/25%), calix[4]resorcinarene derivative as a carrier and 2-nitrophenyl octyl ether (2-NPOE) as plasticizer was investigated. The experimental part of this investigation involved the influence of carrier nature, plasticizer concentration, pH phases, and phenol initial concentration on the removal efficiency of phenol from synthetic wastewater. A PIM containing 0.1 g (of mixture polymer), (0.15 g/g mixture of polymer) of carrier and (0.03 ml/g mixture of polymer) of 2-NPOE provided the highest percentage of phenol removal efficiency over a 6-day transport; the removal was found to be about 95%, indeed the removal was found to be highly dependent of pH phases. The feed solution in these transport experiments was at pH 2, while the stripping solution contained 0.20 M NaOH. This study claims that the PIM with a mixture of cellulose derivatives can be used effectively to remove phenols from wastewaters.

Fluorescent microarray for multiplexed quantification of environmental contaminants in seawater samples.

PubMed

Sanchis, Ana; Salvador, J-Pablo; Campbell, Katrina; Elliott, Christopher T; Shelver, Weilin L; Li, Qing X; Marco, M-Pilar

2018-07-01

The development of a fluorescent multiplexed microarray platform able to detect and quantify a wide variety of pollutants in seawater is reported. The microarray platform has been manufactured by spotting 6 different bioconjugate competitors and it uses a cocktail of 6 monoclonal or polyclonal antibodies raised against important families of chemical pollutants such as triazine biocide (i.e. Irgarol 1051®), sulfonamide and chloramphenicol antibiotics, polybrominated diphenyl ether flame-retardant (PBDE, i.e. BDE-47), hormone (17β-estradiol), and algae toxin (domoic acid). These contaminants were selected as model analytes, however, the platform developed has the potential to detect a broader group of compounds based on the cross-reactivity of the immunoreagents used. The microarray chip is able to simultaneously determine these families of contaminants directly in seawater samples reaching limits of detection close to the levels found in contaminated areas (Irgarol 1051®, 0.19 ± 0,06 µg L -1 ; sulfapyridine, 0.17 ± 0.07 µg L -1 ; chloramphenicol, 0.11 ± 0.03 µg L -1 ; BDE-47, 2.71 ± 1.13 µg L -1 ; 17β-estradiol, 0.94 ± 0.30 µg L -1 and domoic acid, 1.71 ± 0.30 µg L -1 ). Performance of the multiplexed microarray chip was assessed by measuring 38 blind spiked seawater samples containing either one of these contaminants or mixtures of them. The accuracy found was very good and the coefficient of variation was < 20% in all the cases. No sample pre-treatment was necessary, and the results could be obtained in just 1 h 30 min. The microarray shows high sample throughput capabilities, being able to measure simultaneously more than 68 samples and screen them for a significant number of chemical contaminants of interest in environmental screening programs. Copyright © 2018 Elsevier B.V. All rights reserved.

Glove permeation by semiconductor processing mixtures containing glycol-ether derivatives.

PubMed

Zellers, E T; Ke, H Q; Smigiel, D; Sulewski, R; Patrash, S J; Han, M W; Zhang, G Z

1992-02-01

Results of permeation tests of several glove materials challenged with semiconductor processing formulations containing glycolether derivatives are described. Commercial glove samples of nitrile rubber (Edmont), natural rubber (Edmont and Baxter), butyl rubber (North), PVC Baxter), a natural rubber/neoprene/nitrile blend (Pioneer), and a natural rubber/neoprene blend (Playtex) were tested according to the ASTM F739-85 permeation test method (open-loop configuration). The liquid formulations examined included a positive photoresist thinner containing 2-ethoxyethyl acetate (2-EEA), n-butyl acetate, and xylene; a positive photoresist containing 2-EEA, n-butyl acetate, xylene, polymer resins, and photoactive compounds; a negative photoresist containing 2-methoxyethanol (2-ME), xylene, and cyclized poly(isoprene); and pure 2-methoxyethyl acetate (2-MEA), which is the solvent used in a commercial electron-beam resist. With the exception of the negative photoresist, butyl rubber provided the highest level of protection against the solvent mixtures tested, with no breakthrough observed after 4 hr of continuous exposure at 25 degrees C. Nitrile rubber provided the highest level of protection against the negative photoresist and reasonably good protection against initial exposure to the other solvent mixtures. Gloves consisting of natural rubber or natural rubber blends provided less protection against the mixtures than either nitrile or butyl rubber. For most of the glove samples, permeation of the glycol-ether derivatives contained in the mixtures was faster than that predicted from the permeation of the pure solvents. Increasing the exposure temperature from 25 to 37 degrees C did not significantly affect the performance of the butyl rubber glove. For the other gloves, however, exposures at 37 degrees C resulted in decreases in breakthrough times of 25-75% and increases in steady-state permeation rates of 80-457% relative to values obtained at 25 degrees C. Repeated exposure of nitrile rubber samples resulted in shorter breakthrough times for all mixture components. In fact, exposure for as little as one-half of the nominal breakthrough time followed by air drying overnight resulted in measurable quantities of one or more of the component solvents at the inner surface of the gloves at the beginning of the next exposure. This effect was not observed with the butyl rubber samples. With the exception of the negative photoresist, heating previously exposed nitrile rubber samples at 70 degrees C for 20 hr prior to retesting reduced or eliminated the effects of residual solvents, permitting reuse of the gloves. The use of thin PVC or natural rubber gloves adjacent to the nitrile gloves provided moderate increases in permeation resistance.(ABSTRACT TRUNCATED AT 400 WORDS)

Atmospheric Chemistry of Six Methyl-perfluoroheptene-ethers Used as Heat Transfer Fluid Replacement Compounds: Measured OH Radical Reaction Rate Coefficients, Atmospheric Lifetimes, and Global Warming Potentials

NASA Astrophysics Data System (ADS)

Jubb, A. M.; Gierczak, T.; Baasandorj, M.; Waterland, R. L.; Burkholder, J. B.

2013-12-01

Mixtures of methyl-perfluoroheptene-ethers (C7F13OCH3, MPHEs) are currently in use as a replacement for perfluorinated alkane (PFC) and polyether mixtures (both persistent greenhouse gases with atmospheric lifetimes >1000 years) used as heat transfer fluids. Currently, the atmospheric fate of the MPHE isomers are not well characterized, however, reaction with the OH radical is expected to be a dominant tropospheric loss process for these compounds. In order to assess the atmospheric lifetimes and environmental implications of MPHE use, rate coefficients for MPHE isomers' reaction with OH radicals are desired. In the work presented here, rate coefficients, k, for the gas-phase reaction of the OH radical with six MPHEs commonly used in commercial mixtures (isomers and stereoisomers) and their deuterated analogs (d3-MPHE) were determined at 296 K using a relative rate method with combined gas-chromatography/IR spectroscopy detection. A range of OH rate coefficient values was observed, up to a factor of 20× different, between the MPHE isomers with the (E)-stereoisomers exhibiting the greatest reactivity. The measured OH reaction rate coefficients for the d3-MPHE isomers were lower than the observed MPHE values although a large range of k values between isomers was still observed. The reduction in reactivity with deuteration signifies that the MPHE + OH reaction proceeds via both addition to the olefinic C=C bond and H-abstraction from the methyl ester group. OH addition to the C=C bond was determined to be the primary reaction channel. Atmospheric lifetimes with respect to the OH reaction for the six MPHE isomers were found to be in the range of days to months. The short lifetimes indicate that MPHE use will primarily impact tropospheric local and regional air quality. A MPHE atmospheric degradation mechanism will be presented. As part of this work, radiative efficiencies and global warming potentials (GWPs) for the MPHE isomers were estimated based on measured infrared absorption spectra of MPHE mixture samples and infrared spectra calculated theoretically. Here the calculated GWPs for the MPHE isomers are considered to be estimates, as the actual GWPs for short-lived gases will depend greatly on the season and location of their emission. The results presented highlight the importance of quantifying the individual component atmospheric fate for all mixture components when assessing the atmospheric behavior of mixtures.

Improving the de-agglomeration and dissolution of a poorly water soluble drug by decreasing the agglomerate strength of the cohesive powder.

PubMed

Allahham, Ayman; Stewart, Peter J; Das, Shyamal C

2013-11-30

Influence of ternary, poorly water-soluble components on the agglomerate strength of cohesive indomethacin mixtures during dissolution was studied to explore the relationship between agglomerate strength and extent of de-agglomeration and dissolution of indomethacin (Ind). Dissolution profiles of Ind from 20% Ind-lactose binary mixtures, and ternary mixtures containing additional dibasic calcium phosphate (1% or 10%; DCP), calcium sulphate (10%) and talc (10%) were determined. Agglomerate strength distributions were estimated by Monte Carlo simulation of particle size, work of cohesion and packing fraction distributions. The agglomerate strength of Ind decreased from 1.19 MPa for the binary Ind mixture to 0.84 MPa for 1DCP:20Ind mixture and to 0.42 MPa for 1DCP:2Ind mixture. Both extent of de-agglomeration, demonstrated by the concentration of the dispersed indomethacin distribution, and extent of dispersion, demonstrated by the particle size of the dispersed indomethacin, were in descending order of 1DCP:2Ind>1DCP:20Ind>binary Ind. The addition of calcium sulphate dihydrate and talc also reduced the agglomerate strength and improved de-agglomeration and dispersion of indomethacin. While not definitively causal, the improved de-agglomeration and dispersion of a poorly water soluble drug by poorly water soluble components was related to the agglomerate strength of the cohesive matrix during dissolution. Copyright © 2013 Elsevier B.V. All rights reserved.

Study of sulfonated polyether ether ketone with pendant lithiated fluorinated sulfonic groups as ion conductive binder in lithium-ion batteries

NASA Astrophysics Data System (ADS)

Wei, Zengbin; Xue, Lixin; Nie, Feng; Sheng, Jianfang; Shi, Qianru; Zhao, Xiulan

2014-06-01

In an attempt to reduce the Li+ concentration polarization and electrolyte depletion from the electrode porous space, sulfonated polyether ether ketone with pendant lithiated fluorinated sulfonic groups (SPEEK-FSA-Li) is prepared and attempted as ionic conductivity binder. Sulfonated aromatic poly(ether ether ketone) exhibits strong adhesion and chemical stability, and lithiated fluorinated sulfonic side chains help to enhance the ionic conductivity and Li+ ion diffusion due to the charge delocalization over the sulfonic chain. The performances are evaluated by cyclic voltammetry, electrochemical impedance spectroscopy, charge-discharge cycle testing, 180° peel testing, and compared with the cathode prepared with polyvinylidene fluoride binder. The electrode prepared with SPEEK-FSA-Li binder forms the relatively smaller resistances of both the SEI and the charge transfer of lithium ion transport. This is beneficial to lithium ion intercalation and de-intercalation of the cathode during discharging-charging, therefore the cell prepared with SPEEK-FSA-Li shows lower charge plateau potential and higher discharge plateau potential. Compared with PVDF, the electrode with ionic binder shows smaller decrease in capacity with the increasing of cycle rate. Meanwhile, adhesion strength of electrode prepared with SPEEK-FSA-Li is more than five times greater than that with PVDF.

Biofiltration and inhibitory interactions of gaseous benzene, toluene, xylene, and methyl tert-butyl ether.

PubMed

Shim, Eun-Hwa; Kim, Jaisoo; Cho, Kyung-Suk; Ryu, Hee Wook

2006-05-01

This study evaluated the individual and combined removal capacities of benzene, toluene, and xylene (B, T, and X) in the presence and absence of methyl tert-butyl ether (MTBE) in a polyurethane biofilter inoculated with a BTX-degrading microbial consortium, and further examined their interactive effects in various mixtures. In addition, Polymerase chain reaction-denaturing gradient gel electrophoresis and phylogenetic analysis of 16S rRNA gene sequences were used to compare the microbial community structures found in biofilters exposed to the various gases and gas mixtures. The maximum individual elimination capacities (MECs) of B, T, and X were 200, 238, and 400 g m(-3) h(-1), respectively. There was no significant elimination of MTBE alone. Addition of MTBE decreased the MECs of B,T, and X to 75, 100, and 300 g m(-3) h(-1), respectively, indicating that benzene was most strongly inhibited by MTBE. When the three gases were mixed (B + T + X), the removal capacities of individual B, T, and X were 50, 90, and 200 g m(-3) h(-1), respectively. These capacities decreased to 40, 50, and 100 g m(-3) h(-1) when MTBE was added to the mix. The MEC of the three-gas mixture (B + T + X) was 340 g m(-3) h(-1), and that of the four-gas mixture was 200 g m(-3) h(-1). Although MTBE alone was not degraded by the biofilter, it could be co-metabolically degraded in the presence of toluene, benzene, or xylene with the MECs of 34, 23, and 14 g m(-3) h(-1), respectively. The microbial community structure analysis revealed that two large groups could be distinguished based on the presence or absence of MTBE, and many of the dominant bacteria in the consortia were closely related to bacteria isolated from aromatic hydrocarbon-contaminated sites and/ or oil wastewaters. These findings provide important new insights into biofiltration and may be used to improve the rational design of biofilters for remediation of petroleum gas-contaminated airstreams according to composition types of mixed gases.

Draft genome sequence of Methylibium sp. strain T29, a novel fuel oxygenate-degrading bacterial isolate from Hungary.

PubMed

Szabó, Zsolt; Gyula, Péter; Robotka, Hermina; Bató, Emese; Gálik, Bence; Pach, Péter; Pekker, Péter; Papp, Ildikó; Bihari, Zoltán

2015-01-01

Methylibium sp. strain T29 was isolated from a gasoline-contaminated aquifer and proved to have excellent capabilities in degrading some common fuel oxygenates like methyl tert-butyl ether, tert-amyl methyl ether and tert-butyl alcohol along with other organic compounds. Here, we report the draft genome sequence of M. sp. strain T29 together with the description of the genome properties and its annotation. The draft genome consists of 608 contigs with a total size of 4,449,424 bp and an average coverage of 150×. The genome exhibits an average G + C content of 68.7 %, and contains 4754 protein coding and 52 RNA genes, including 48 tRNA genes. 71 % of the protein coding genes could be assigned to COG (Clusters of Orthologous Groups) categories. A formerly unknown circular plasmid designated as pT29A was isolated and sequenced separately and found to be 86,856 bp long.

Reactivity of long chain alkylamines to lignin moieties: implications on hydrophobicity of lignocellulose materials.

PubMed

Kudanga, Tukayi; Prasetyo, Endry Nugroho; Sipilä, Jussi; Guebitz, Georg M; Nyanhongo, Gibson S

2010-08-20

Enzymatic processes provide new perspectives for modification of lignocellulose materials. In the current study, laccase catalyzed coupling of long chain alkylamines to lignin model molecules and lignocellulose was investigated. Up to two molecules of dodecylamine (DA) and dihexylamine (DHA) were successfully coupled with lignin monomers (guaiacol, catechol and ferulic acid) while coupling onto complex lignin model compounds (syringylglycerol beta-guaiacyl ether, guaiacylglycerol beta-guaiacyl ether and dibenzodioxocin) yielded 1:1 coupling products. Surface analysis of beech veneers enzymatically grafted with DA showed an increase in nitrogen content of 3.18% compared to 0.71% in laccase only treated controls while the O/C ratio decreased from 0.52 to 0.46. Concomitantly the grafting of DHA or DA onto beech veneers resulted in a 53.8% and 84.2% increase in hydrophobicity, respectively when compared to simple adsorption. Therefore, laccase-mediated grafting of long chain alkylamines onto lignocellulose materials can be potentially exploited for improving their hydrophobicity. Copyright 2010 Elsevier B.V. All rights reserved.

Tree bark as a biomonitor for the determination of polychlorinated biphenyls and polybrominated diphenyl ethers from Southern Jiangsu, China: levels, distribution, and possible sources.

PubMed

Zhou, Li; Dong, Liang; Huang, Ye-Ru; Shi, Shuang-Xin; Zhang, Li-Fei; Zhang, Xiu-Lan; Yang, Wen-Long

2015-09-01

Tree bark was used as the passive air sampler to evaluate polychlorinated biphenyl (PCB) and polybrominated diphenyl ether (PBDE) pollution and possible sources in Southern Jiangsu. The concentrations of PCBs and Σ7PBDEs were in the range of 0.58-5.19 ng/g dry weight (dw; mean 1.79 ng/g dw) and 17.9-243 pg/g dw (mean 74.7 pg/g dw), respectively. Tri-PCBs were the major PCB homologs, and technical PCB product Ar1242 was identified as the main source. BDE209 concentrations (4.29-456 ng/g dw) were relatively high, indicating that BDE209 pollution was serious in this region. The deca-BDE commercial mixture was the predominant commercial PBDE product used in this region. A good correlation was found between tree bark and polyurethane foam (PUF) disks in Σ6PCB monitoring, suggesting that both of them respond well to the gas-phase PCB monitoring.

Detection and measurement of organic lampricide residues

USGS Publications Warehouse

Daniels, Stacy L.; Kempe, Lloyd L.; Billy, Thomas J.; Beeton, Alfred M.

1965-01-01

The selective lampricide, 3-trifluoromethyl-4-nitrophenol (TFM), and its synergist, 5,2'-dichloro-4'-nitrosalicylanilide (DCN), are separable from natural waters by anion exchange. The adsorbed compounds can then be recovered from the resin as concentrates by elution with selective solvent mixtures. Measurements of the amounts of lampricides in the final concentrates can be made colorimetrically at 395 mI? for TFM and at 530 mI? for the safranin complex of DCN. TFM has also been separated for quantitative determination from homogenates of whole fish. The fish is first macerated in a blender and then hydrolyzed in hot, 3 N hydrochloric acid. The amount of background color, due to certain components of the fish in the hydrolysate, is reduced by one or a combination of three methods: (1) a series of three extractions with ether, methylene chloride, and benzene; (2) cation exchange followed by methylene chloride extraction; or (3) ether extraction followed by anion exchange and subsequent desorption with amyl acetate-acetic acid.

Process for conversion of lignin to reformulated, partially oxygenated gasoline

DOEpatents

Shabtai, Joseph S.; Zmierczak, Wlodzimierz W.; Chornet, Esteban

2001-01-09

A high-yield process for converting lignin into reformulated, partially oxygenated gasoline compositions of high quality is provided. The process is a two-stage catalytic reaction process that produces a reformulated, partially oxygenated gasoline product with a controlled amount of aromatics. In the first stage of the process, a lignin feed material is subjected to a base-catalyzed depolymerization reaction, followed by a selective hydrocracking reaction which utilizes a superacid catalyst to produce a high oxygen-content depolymerized lignin product mainly composed of alkylated phenols, alkylated alkoxyphenols, and alkylbenzenes. In the second stage of the process, the depolymerized lignin product is subjected to an exhaustive etherification reaction, optionally followed by a partial ring hydrogenation reaction, to produce a reformulated, partially oxygenated/etherified gasoline product, which includes a mixture of substituted phenyl/methyl ethers, cycloalkyl methyl ethers, C.sub.7 -C.sub.10 alkylbenzenes, C.sub.6 -C.sub.10 branched and multibranched paraffins, and alkylated and polyalkylated cycloalkanes.

Mumijo Traditional Medicine: Fossil Deposits from Antarctica (Chemical Composition and Beneficial Bioactivity)

PubMed Central

Aiello, Anna; Fattorusso, Ernesto; Menna, Marialuisa; Vitalone, Rocco; Schröder, Heinz C.; Müller, Werner E. G.

2011-01-01

Mumijo is a widely used traditional medicine, especially in Russia, Altai Mountains, Mongolia, Iran Kasachstan and in Kirgistan. Mumijo preparations have been successfully used for the prevention and treatment of infectious diseases; they display immune-stimulating and antiallergic activity as well. In the present study, we investigate the chemical composition and the biomedical potential of a Mumijo(-related) product collected from the Antarctica. The yellow material originates from the snow petrels, Pagodroma nivea. Extensive purification and chemical analysis revealed that the fossil samples are a mixture of glycerol derivatives. In vitro experiments showed that the Mumijo extract caused in cortical neurons a strong neuroprotective effect against the apoptosis-inducing amyloid peptide fragment β-fragment 25–35 (Aβ25–35). In addition, the fraction rich in glycerol ethers/wax esters displayed a significant growth-promoting activity in permanent neuronal PC12 cells. It is concluded that this new Mumijo preparation has distinct and marked neuroprotective activity, very likely due to the content of glycerol ether derivatives. PMID:18996940

Unique low-molecular-weight lignin with high purity extracted from wood by deep eutectic solvents (DES): a source of lignin for valorization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alvarez-Vasco, Carlos; Ma, Ruoshui; Quintero, Melissa

This paper reports a new method of applying Deep Eutectic Solvents (DES) for extracting lignin from woody biomass with high yield and high purity. DES mixtures prepared from Choline Chloride (ChCl) and four hydrogen-bond donors–acetic acid, lactic acid, levulinic acid and glycerol–were evaluated for treatment of hardwood (poplar) and softwood (D. fir). It was found that these DES treatments can selectively extract a significant amount of lignin from wood with high yields: 78% from poplar and 58% from D. fir. The extracted lignin has high purity (95%) with unique structural properties. We discover that DES can selectively cleave ether linkagesmore » in wood lignin and facilitate lignin removal from wood. The mechanism of DES cleavage of ether bonds between phenylpropane units was investigated. The results from this study demonstrate that DES is a promising solvent for wood delignification and the production of a new source of lignin with promising potential applications.« less

Enhanced debromination of decabrominated diphenyl ether in aqueous solution by attapulgite supported Fe/Ni bimetallic nanoparticles: kinetics and pathways

NASA Astrophysics Data System (ADS)

Liu, Zongtang; Gu, Chenggang; Bian, Yongrong; Jiang, Xin; Sun, Yufeng; Fei, Zhenghao; Dai, Jingtao

2017-08-01

In this study, Fe/Ni bimetallic nanoparticles were supported on the attapulgite (A-Fe/Ni) to enhance the degradation reactivity of decabrominated diphenyl ether (BDE209) in aqueous solution. The Fe/Ni nanoparticles were well distributed on the attapulgite surface with an average diameter of 20-40 nm. The removal percentage of BDE209 by A-Fe/Ni was 1.59 times higher than Fe/Ni nanoparticles alone because attapulgite could act as supporting material to disperse Fe/Ni nanoparticles and prevent Fe/Ni nanoparticles from aggregation. The degradation kinetics for BDE209 debromination by A-Fe/Ni could be well described by a pseudo-first-order model, and the debromination rate constant of BDE209 increased with increasing the dosage of A-Fe/Ni, water/THF ratio, and decreasing the initial BDE209 concentration and solution pH. The degradation products were identified using a third-order polynomial regression equation between the experimental and reference gas chromatography relative retention times. Stepwise debromination from n-bromo-DE to (n  -  1)-bromo-DE was a possible pathway with bromines being substituted sequentially by hydrogen. The preferred elimination of bromines of BDE209 by A-Fe/Ni followed the debromination preference of para-Br  >  meta-Br  >  ortho-Br. The results provide evidences for understanding the debromination mechanism of polybrominated diphenyl ether by clay-supported Fe/Ni nanoparticles.

INVESTIGATION OF A MIXTURE CONTAINING ALPRAZOLAM, CODEINE AND PARACETAMOL USING THIN-LAYER AND HIGH PERFORMANCE LIQUID CHROMATOGRAPHY METHODS.

PubMed

Ciegis, Paulius; Zevzikovas, Andrejus; Zevzikoviene, Augusta; Nenortiene, Palma; Kazlauskiene, Daiva

2016-01-01

The increasing drug consumption in Lithuania and all over the world makes us think about the negative consequences - the risk of toxicity. Fast and accurate identification of material that caused the poisoning reduces the probability in death cases and makes easier to determine the main cause of death. The results have shown that the most appropriate systems of solvents for qualitative analysis by TLC method of the mixture consisting of alprazolam, codeine and paracetanol are: system "D" (trichloromethane : acetone : conc. ammonia = 55 : 40 : 5 (v/v/v)) and system "F" (trichloromethane : diethyl ether: isobutanol : conc. ammonia = 50 : 30 : 15 : 5 (v/v/v/v)). For qualitative analysis of the mixture consisting of alprazolam, codeine and paracetamol by HPLC method the chromatographic column ACE C18 (25 cm x 4.6 mm x 5 µm), gradient elution mode (mixture of 3% acetic acid and methanol and the flow rate 1 mL/min have been used. The injection volume was 10 pL. Photodiode array detector (210 - 240 nm range) has been used. UV absorption spectra of materials measured using photodiode array detector have been identical to those presented in the scientific literature.

Mixtures of glyme and aprotic-protic ionic liquids as electrolytes for energy storage devices

NASA Astrophysics Data System (ADS)

Stettner, T.; Huang, P.; Goktas, M.; Adelhelm, P.; Balducci, A.

2018-05-01

Ionic liquids (ILs) have been proven to be promising electrolytes for electrochemical energy storage devices such as supercapacitors and lithium ion batteries. In the last years, due to deficiency in storage of lithium on earth, innovative systems, such as sodium-based devices, attracted considerable attention. IL-based electrolytes have been proposed also as electrolytes for these devices. Nevertheless, in the case of these systems, the advantages and limits of IL-based electrolytes need to be further investigated. In this work we report an investigation about the chemical-physical properties of mixtures containing bis(2-methoxyethyl)ether diglyme (2G), which is presently considered as one of the most interesting solvents for sodium-based devices, and the ionic liquids 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI) and 1-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PyrH4TFSI). The conductivities, viscosities, and densities of several mixtures of 2G and these ILs have been investigated. Furthermore, their impact on the electrochemical behaviour of activated carbon composite electrodes has been considered. The results of this investigation indicate that these mixtures are promising electrolytes for the realization of advanced sodium-based devices.

Gene expression profiles in rainbow trout, Onchorynchus mykiss, exposed to a simple chemical mixture.

PubMed

Hook, Sharon E; Skillman, Ann D; Gopalan, Banu; Small, Jack A; Schultz, Irvin R

2008-03-01

Among proposed uses for microarrays in environmental toxiciology is the identification of key contributors to toxicity within a mixture. However, it remains uncertain whether the transcriptomic profiles resulting from exposure to a mixture have patterns of altered gene expression that contain identifiable contributions from each toxicant component. We exposed isogenic rainbow trout Onchorynchus mykiss, to sublethal levels of ethynylestradiol, 2,2,4,4-tetrabromodiphenyl ether, and chromium VI or to a mixture of all three toxicants Fluorescently labeled complementary DNA (cDNA) were generated and hybridized against a commercially available Salmonid array spotted with 16,000 cDNAs. Data were analyzed using analysis of variance (p<0.05) with a Benjamani-Hochberg multiple test correction (Genespring [Agilent] software package) to identify up and downregulated genes. Gene clustering patterns that can be used as "expression signatures" were determined using hierarchical cluster analysis. The gene ontology terms associated with significantly altered genes were also used to identify functional groups that were associated with toxicant exposure. Cross-ontological analytics approach was used to assign functional annotations to genes with "unknown" function. Our analysis indicates that transcriptomic profiles resulting from the mixture exposure resemble those of the individual contaminant exposures, but are not a simple additive list. However, patterns of altered genes representative of each component of the mixture are clearly discernible, and the functional classes of genes altered represent the individual components of the mixture. These findings indicate that the use of microarrays to identify transcriptomic profiles may aid in the identification of key stressors within a chemical mixture, ultimately improving environmental assessment.

House crickets can accumulate polybrominated diphenyl ethers (PBDEs) directly from polyurethane foam common in consumer products.

PubMed

Gaylor, Michael O; Harvey, Ellen; Hale, Robert C

2012-02-01

Polybrominated diphenyl ether (PBDE) flame retardants are added at percent levels to many polymers and textiles abundant in human spaces and vehicles, wherein they have been long assumed to be tightly sequestered. However, the mgkg(-1) burdens recently detected in indoor dust testify to substantial releases. The bulk of released PBDEs remain in the terrestrial environment, yet comparatively little research focuses on this compartment. There, insects/arthropods, such as crickets, are the most abundant invertebrate organisms and facilitate the trophic transfer of contaminants by breaking down complex organic matter (including discarded polymers) and serving as food for other organisms. Our experiments revealed that house crickets (Acheta domesticus) provided uncontaminated food and free access to PUF containing Penta-BDE (8.7%drywt) for 28 d accumulated substantial PBDE body burdens. Crickets allowed to depurate gut contents exhibited whole body burdens of up to 13.4 mg kg(-1) lipid ΣPenta-BDE, 1000-fold higher than typically reported in humans. Non-depurated crickets and molted exoskeletons incurred even higher ΣPenta-BDE, up to 80.6 and 63.3 mg kg(-1) lipid, respectively. Congener patterns of whole crickets and molts resembled those of PUF and the commercial Penta-BDE formulation, DE-71, indicative of minimal discrimination or biotransformation. Accumulation factor (AF) calculations were hampered by uncertainties in determining actual PUF ingestion. However, estimated AFs were low, in the range of 10(-4)-10(-3), suggesting that polymer-PBDE interactions limited uptake. Nonetheless, results indicate that substantial PBDE burdens may be incurred by insects in contact with current-use and derelict treated polymers within human spaces and solid waste disposal sites (e.g. landfills, automotive dumps, etc.). Once ingested, even burdens not absorbed across the gut wall may be dispersed within proximate terrestrial food webs via the insect's movements and/or predation. Copyright © 2011 Elsevier Ltd. All rights reserved.

[Studies on determination of p-aminophenol and its related compounds prepared with catalytic hydrogenation by reversed-phase high performance liquid chromatography].

PubMed

Li, S; Gu, H; Zheng, M; Zhan, Y

1997-07-01

Catalytic hydrogenation of nitrobenzene with supported palladium catalyst is a new method to produce p-aminophenol. p-Aminophenol, aniline and 4,4'-diaminodiphenyl ether obtained from this method were determined by reversed phase high performance liquid chromatography. The factors, e.g., concentration of methanol, pH and ionic strength which could affect separation efficiency were studied. UV spectra of p-aminophenol, aniline and 4,4'-diaminodiphenyl ether were recorded. Good separation was performed by using a 100 mm x 4.6 mm column with 5 microm Hypersil ODS, a mixture of 60% aqueous 8.0 mmol/L KH2PO4 buffered to 6.5 with 4.0 mmol/L Na2HPO4 and 40% methanol as mobile phase at a flow rate of 1.0 mL/min, and UV spectrophotometric detector at 232 nm wavelength. The calibration curves of p-aminophenol, aniline and 4,4'-diaminodiphenyl ether have good linearity over concentration range of 5-250, 5-150 and 0.2-120 mg/L, respectively. Minimum detectable limits at a signal-to-noise ratio of 2 were 0.1, 0.6 and 0.6 ng. This method has been applied to analysis of the reaction products of ultrasonic catalytic hydrogenation and industrial samples with good results and reproducibility.

Multi-stimuli-responsive organometallic gels based on ferrocene-linked poly(aryl ether) dendrons: reversible redox switching and Pb2+-ion sensing.

PubMed

Lakshmi, Neelakandan Vidhya; Mandal, Dipendu; Ghosh, Sundargopal; Prasad, Edamana

2014-07-14

We describe the design, synthesis, and "stimuli-responsive" study of ferrocene-linked Fréchet-type [poly(aryl ether)]-dendron-based organometallic gels, in which the ferrocene moiety is attached to the dendron framework through an acyl hydrazone linkage. The low-molecular-weight gelators (LMWGs) form robust gels in both polar and non-polar solvent/solvent mixtures. The organometallic gels undergo stimuli-responsive behavior through 1) thermal, 2) chemical, and 3) electrochemical methods. Among them, conditions 1 and 3 lead to seamlessly reversible with repeated cycles of identical efficiency. Results indicate that the flexible nature of the poly(aryl ether) dendron framework plays a key role in retaining the reversible electrochemical behavior of ferrocene moiety in the LMWGs. Further, the organometallic gelators have exhibited unique selectivity towards Pb(2+) ions (detection limit ≈10(-8)  M). The metal ion-sensing results in a gel-sol phase transition associated with a color change visible to the naked eye. Most importantly, decomplexing the metal ion from the system leads to the regeneration of the initial gel morphology, indicating the restoring ability of the organometallic gel. The metal-ligand binding nature has been analyzed by using (1)H NMR spectroscopy, mass spectrometry, and DFT calculations. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structural distinction of diacyl-, alkylacyl, and alk-1-enylacyl glycerophosphocholines as [M - 15]⁻ ions by multiple-stage linear ion-trap mass spectrometry with electrospray ionization.

PubMed

Hsu, Fong-Fu; Lodhi, Irfan J; Turk, John; Semenkovich, Clay F

2014-08-01

We describe a linear ion-trap (LIT) multiple-stage (MS(n)) mass spectrometric approach towards differentiation of alkylacyl, alk-1-enylacyl- and diacyl-glycerophoscholines (PCs) as the [M - 15]⁻ ions desorbed by electrospray ionization (ESI) in the negative-ion mode. The MS⁴ mass spectra of the [M - 15 - R²'CH = CO]⁻ ions originated from the three PC subfamilies are readily distinguishable, resulting in unambiguous distinction of the lipid classes. This method is applied to two alkyl ether rich PC mixtures isolated from murine bone marrow neutrophils and kidney, respectively, to explore its utility in the characterization of complex PC mixture of biological origin, resulting in the realization of the detailed structures of the PC species, including various classes and many minor isobaric isomers.

Studies on the oxidation of hexamethylbenzene 1: Oxidation of hexamethylbenzene with nitric acid

NASA Technical Reports Server (NTRS)

Chiba, K.; Tomura, S.; Mizuno, T.

1986-01-01

The oxidative reaction of hexamethylbenzene (HMB) with nitric acid was studied, and the hitherto unknown polymethylbenzenepolycarboxylic acids were isolated: tetramethylphthalic anhydride, tetramethylisophthalic acid, 1,3,5-, 1,2,4- and 1,2,3-trimethylbenzenetricarboxylic acids. When HMB was warmed with 50% nitric acid at about 80 C, tetramethylphthalic anhydride and tetramethylisophthalic acid were initially produced. The continued reaction led to the production of trimethylbenzenetricarboxylic acids, but only slight amounts of dimethylbenzenetetracarboxylic acids were detected in the reaction mixture. Whereas tetramethylphthalic anydride and tetramethylisophthalic acid were obtained, pentamethylbenzoic acid, a possible precursor of them, was scarcely produced. On the other hand, a yellow material extracted with ether from the initial reaction mixture contained bis-(nitromethyl)prehnitene (CH3)4C6(CH2NO2)2, which was easily converted into the phthalic anhydride.

An Approach for Peptide Identification by De Novo Sequencing of Mixture Spectra.

PubMed

Liu, Yi; Ma, Bin; Zhang, Kaizhong; Lajoie, Gilles

2017-01-01

Mixture spectra occur quite frequently in a typical wet-lab mass spectrometry experiment, which result from the concurrent fragmentation of multiple precursors. The ability to efficiently and confidently identify mixture spectra is essential to alleviate the existent bottleneck of low mass spectra identification rate. However, most of the traditional computational methods are not suitable for interpreting mixture spectra, because they still take the assumption that the acquired spectra come from the fragmentation of a single precursor. In this manuscript, we formulate the mixture spectra de novo sequencing problem mathematically, and propose a dynamic programming algorithm for the problem. Additionally, we use both simulated and real mixture spectra data sets to verify the merits of the proposed algorithm.

Effect of benzene, toluene, ethylbenzene, and p-xylene (BTEX) mixture on biodegradation of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) by pure culture UC1.

PubMed

Pruden, Amy; Suidan, Makram

2004-08-01

The effect of a BTEX mixture on the biodegradation of methyl tert-butyl ether (MTBE) and its degradation intermediate, tert-butyl alcohol (TBA) was investigated in the pure bacterial culture UC1, which has been identified to be a strain of the known MTBE-degrader PM1 based on greater than 99% 16S rDNA similarity. Several degradation studies were carried out on UC1 at three initial concentration levels of MTBE or TBA: 6-7; 15-17; and 40-45 mg/l, both with and without BTEX present cumulatively at about half of the MTBE or TBA molar mass in the system. The BTEX mixture was observed not to affect either the rate or the degradation lag period of MTBE or TBA degradation, except that the TBA degradation rate actually increased when BTEX was present initially in the highest concentration studies. When serving as the sole substrate, the MTBE degradation rate ranged from 48 +/- 1.2 to 200 +/- 7.0 mg(MTBE)/g(dw) h, and the TBA degradation rate from 140 +/- 18 to 530 +/- 70 mg(TBA)/g(dw) h. When present with BTEX, MTBE and TBA rates ranged from 46 +/- 2.2 to 210 +/- 14 and 170 +/- 28 to 780 +/- 43 mg(TBA)/g(dw) h, respectively. In studies where varying concentrations of TBA were present with 5 mg/l MTBE, both compounds were degraded simultaneously with no obvious preference for either substrate. In the highest concentration study of TBA with 5 mg/l MTBE, BTEX was also observed to increase the ultimate rate of TBA degradation. In addition to exploring the affect of BTEX, this study also provides general insight into the metabolism of MTBE and TBA by pure culture UC1.

Siloxane containing addition polyimides

NASA Technical Reports Server (NTRS)

Maudgal, S.; St. Clair, T. L.

1984-01-01

Addition polyimide oligomers have been synthesized from bis(gamma-aminopropyl) tetramethyldisiloxane and 3, 3', 4, 4'-benzophenonetetracarboxylic dianhydride using a variety of latent crosslinking groups as endcappers. The prepolymers were isolated and characterized for solubility (in amide, chlorinated and ether solvents), melt flow and cure properties. The most promising systems, maleimide and acetylene terminated prepolymers, were selected for detailed study. Graphite cloth reinforced composites were prepared and properties compared with those of graphite/Kerimid 601, a commercially available bismaleimide. Mixtures of the maleimide terminated system with Kerimid 601, in varying proportions, were also studied.

Modeling Joint Effects of Mixtures of Chemicals on Microorganisms Using Quantitative Structure Activity Relationships

DTIC Science & Technology

1993-08-22

Cyclohexane Alk 74 133 26 Pentane Alk 70 150 27 Hexane Alk 38 47 28 Heptane Alk 18 58 29 Octane Alk 8 60 30 Bis (2-chloroethyl) ether Alc 1,600 3,025 31...Triethanolarnine Amni 900 741 SAro- aromatic; Hal- balogemmaed aliphatic; Alk - alkanes; Alc- alcohols, este’s, ketones and et Aji- amineL -5- Correlation...chemicals using laboratory grown activated sludge by synthetic feed. They adapted the OECD Method 209, using inhibition of oxygen uptake rate as the measure

Mechanistic Analysis of Oxidative C–H Cleavages Using Inter- and Intramolecular Kinetic Isotope Effects

PubMed Central

Jung, Hyung Hoon; Floreancig, Paul E.

2009-01-01

A series of monodeuterated benzylic and allylic ethers were subjected to oxidative carbon–hydrogen bond cleavage to determine the impact of structural variation on intramolecular kinetic isotope effects in DDQ-mediated cyclization reactions. These values are compared to the corresponding intermolecular kinetic isotope effects that were accessed through subjecting mixtures of non-deuterated and dideuterated substrates to the reaction conditions. The results indicate that carbon–hydrogen bond cleavage is rate determining and that a radical cation is most likely a key intermediate in the reaction mechanism. PMID:20640173

Production of chemicals and fuels from biomass

DOEpatents

Qiao, Ming; Woods, Elizabeth; Myren, Paul; Cortright, Randy; Kania, John

2018-01-23

Methods, reactor systems, and catalysts are provided for converting in a continuous process biomass to fuels and chemicals, including methods of converting the water insoluble components of biomass, such as hemicellulose, cellulose and lignin, to volatile C.sub.2+O.sub.1-2 oxygenates, such as alcohols, ketones, cyclic ethers, esters, carboxylic acids, aldehydes, and mixtures thereof. In certain applications, the volatile C.sub.2+O.sub.1-2 oxygenates can be collected and used as a final chemical product, or used in downstream processes to produce liquid fuels, chemicals and other products.

Management, nutrition, and lactation performance are related to bulk tank milk de novo fatty acid concentration on northeastern US dairy farms.

PubMed

Woolpert, M E; Dann, H M; Cotanch, K W; Melilli, C; Chase, L E; Grant, R J; Barbano, D M

2016-10-01

This study investigated the relationship of management practices, dietary characteristics, milk composition, and lactation performance with de novo fatty acid (FA) concentration in bulk tank milk from commercial dairy farms with Holstein, Jersey, and mixed-breed cows. It was hypothesized that farms with higher de novo milk FA concentrations would more commonly use management and nutrition practices known to optimize ruminal conditions that enhance de novo synthesis of milk FA. Farms (n=44) located in Vermont and northeastern New York were selected based on a history of high de novo (HDN; 26.18±0.94g/100g of FA; mean ± standard deviation) or low de novo (LDN; 24.19±1.22g/100g of FA) FA in bulk tank milk. Management practices were assessed during one visit to each farm in March or April, 2014. Total mixed ration samples were collected and analyzed for chemical composition using near infrared spectroscopy. We found no differences in days in milk at the farm level. Yield of milk fat, true protein, and de novo FA per cow per day were higher for HDN versus LDN farms. The HDN farms had lower freestall stocking density (cows/stall) than LDN farms. Additionally, tiestall feeding frequency was higher for HDN than LDN farms. No differences between HDN and LDN farms were detected for dietary dry matter, crude protein, neutral detergent fiber, starch, or percentage of forage in the diet. However, dietary ether extract was lower for HDN than LDN farms. This research indicates that overcrowded freestalls, reduced feeding frequency, and greater dietary ether extract content are associated with lower de novo FA synthesis and reduced milk fat and true protein yields on commercial dairy farms. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Numerical modeling and analytical modeling of cryogenic carbon capture in a de-sublimating heat exchanger

NASA Astrophysics Data System (ADS)

Yu, Zhitao; Miller, Franklin; Pfotenhauer, John M.

2017-12-01

Both a numerical and analytical model of the heat and mass transfer processes in a CO2, N2 mixture gas de-sublimating cross-flow finned duct heat exchanger system is developed to predict the heat transferred from a mixture gas to liquid nitrogen and the de-sublimating rate of CO2 in the mixture gas. The mixture gas outlet temperature, liquid nitrogen outlet temperature, CO2 mole fraction, temperature distribution and de-sublimating rate of CO2 through the whole heat exchanger was computed using both the numerical and analytic model. The numerical model is built using EES [1] (engineering equation solver). According to the simulation, a cross-flow finned duct heat exchanger can be designed and fabricated to validate the models. The performance of the heat exchanger is evaluated as functions of dimensionless variables, such as the ratio of the mass flow rate of liquid nitrogen to the mass flow rate of inlet flue gas.

Development of new polyphenols applied to spin-on carbon hardmask with characteristics of high-heat resistance and good planarization

NASA Astrophysics Data System (ADS)

Horiuchi, Junya; Takigawa, Tomoaki; Shimizu, Yoko; Makinoshima, Takashi; Sato, Takashi; Echigo, Masatoshi

2018-03-01

We had developed various Polyphenols and Xanthene derivatives such as NF7177C and NF0197 which showed high heat resistance. In this paper, we reported on new Xanthene derivatives and Polyphenols with characteristics of not only high heat resistance but also low Tg which contributes to good planarization characteristic of Spin-On Carbon Hardmask [1]. One approach to decrease Tg is introducing alkyl group into the Xanthene derivatives. We synthesized the new Xanthene derivatives by the reaction of dihydroxynaphthalene with the aldehydes containing alkyl group. These Xanthene derivatives containing alkyl group showed lower Tg than those not containing alkyl group by about 20 30°C. Another approach to decrease Tg is increasing flexibility of molecular structure. We synthesized the new Polyphenols (NF71C7, NF71D7, NF91A7, and NF71A7) by the reaction of flexible or asymmetric phenols such as 4,4'- dihydroxydiphenyl ether or 4-phenylphenol. The Tg of these Polyphenols was 70 80°C and these values were much lower than the existing polyphenol (NF7177C) synthesized from 4,4-biphenol by about 50°C. We evaluated heat resistance of these Polyphenols with additive, and both NF71C7 and NF71D7 showed comparable heat resistance to NF0197 and NF7177C.

Natural mixtures of persistent organic pollutants (POP) increase weight gain, advance puberty, and induce changes in gene expression associated with steroid hormones and obesity in female zebrafish.

PubMed

Lyche, Jan L; Nourizadeh-Lillabadi, Rasoul; Almaas, Camilla; Stavik, Benedicte; Berg, Vidar; Skåre, Janneche Utne; Alestrøm, Peter; Ropstad, Erik

2010-01-01

In the present study, developmental and reproductive effects of lifelong exposure to environmental relevant concentrations of two natural mixtures of persistent organic pollutants (POP) were investigated using classical and molecular methods in a controlled zebrafish model. The mixtures used were extracted from burbot (Lota lota) liver originating from freshwater systems in Norway: one mixture with high levels and one mixture with background levels of polybrominated diphenyl ethers (PBDE), polychlorinated biphenyls (PCB), and dichlorodiphenyltrichloroethane metabolites (DDT). The concentration of POP measured in the zebrafish ranged from levels detected in wild fish from Lake Mjøsa to concentrations reported in human and wildlife populations, indicating that the experimental fish were exposed to concentrations comparable with wild fish. Phenotypic effects observed in both exposure groups included earlier onset of puberty, increased male/female sex ratio, and differences in body weight at 5 mo of age. Interestingly, genome-wide transcription profiling showed changes in regulation of genes involved in endocrine signaling and growth. The transcriptomics changes include key regulator genes for steroid hormone functions (ncoa3), and growth (c/ebp, ncoa3). The effects observed in the experimental zebrafish model raise the question whether chemical pollution represents a risk to reproductive health of wild fish inhabitating the freshwater system.

Preparation of quaternary amine monolithic column for strong anion-exchange chromatography and its application to the separation of Enterovirus 71.

PubMed

Gu, Huimin; Yin, Dezhong; Ren, Jie; Zhang, Baoliang; Zhang, Qiuyu

2016-10-15

Large size virion is unable to diffuse into pores of conventional porous chromatography particles. Therefore, separation of virion by conventional column-packing materials is not quite efficient. To solve this problem, a monolithic column with large convective pores and quaternary amine groups was prepared and was applied to separate Enterovirus 71 (EV71, ≈5700-6000kDa). Cross-section, pore structure, hydrodynamic performance, adsorption property and dynamic binding capacity of prepared monolithic column were determined. Double-pore structures, macropore at 2472nm and mesopore at 5-60nm, were formed. The porosity was up to 63.3%, which enable higher permeability and lower back pressure of the monolithic column than commercial UNO™ Q1 column. Based on the breakthrough curves, the loading capacity of bovine serum albumin was calculated to be 42.0mg per column. In addition, prepared quaternary amine monolithic column was proved to be suitable for the separation of protein mixture by strong anion-exchange chromatography. As a practical application, prepared monolith column presents excellent performance to the separation of EV71 from virus-proteins mixture. Copyright © 2016 Elsevier B.V. All rights reserved.

Ecotoxicological characterization of polyoxyethylene glycerol ester non-ionic surfactants and their mixtures with anionic and non-ionic surfactants.

PubMed

Ríos, Francisco; Fernández-Arteaga, Alejandro; Lechuga, Manuela; Fernández-Serrano, Mercedes

2017-04-01

This paper reports on a study that investigated the aquatic toxicity of new non-ionic surfactants derived from renewable raw materials, polyoxyethylene glycerol ester (PGE), and their binary mixtures with anionic and non-ionic surfactants. Toxicity of pure PGEs was determined using representative organisms from different trophic levels: luminescent bacteria (Vibrio fischeri), microalgae (Pseudokirchneriella subcapitata), and freshwater crustaceans (Daphnia magna). Relationships between toxicity and the structural parameters such as unit of ethylene oxide (EO) and hydrophilic-lipophilic balance (HLB) were evaluated. Critical micellar concentration (CMC) in the conditions of the toxicity test was also determined. It was found that the toxicity of the aqueous solutions of PGE decreased when the number of EO units in the molecule, HLB, and CMC increased. PGEs showed lower CMC in marine medium, and the toxicity to V. ficheri is lower when the CMC was higher. Given their non-polar nature, narcosis was expected to be the primary mode of toxic action of PGEs. For the mixture of surfactants, we observed that the mixtures with PGE that had the higher numbers of EO units were more toxic than the aqueous solutions of pure surfactants. Moreover, we found that concentration addition was the type of action more likely to occur for mixtures of PGE with lower numbers of EO units with non-ionic surfactants (alkylpolyglucoside and fatty alcohol ethoxylate), whereas for the mixture of PGE with lower EO units and anionic surfactant (ether carboxylic derivative), the most common response type was response addition. In case of mixtures involving amphoteric surfactants and PGEs with the higher numbers of EO units, no clear pattern with regard to the mixture toxicity response type could be observed.

Anandamide and analogous endocannabinoids: a lipid self-assembly study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sagnella, Sharon M.; Conn, Charlotte E.; Krodkiewska, Irena

Anandamide, the endogenous agonist of the cannabinoid receptors, has been widely studied for its interesting biological and medicinal properties and is recognized as a highly significant lipid signaling molecule within the nervous system. Few studies have, however, examined the effect of the physical conformation of anandamide on its function. The study presented herein has focused on characterizing the self-assembly behaviour of anandamide and four other endocannabinoid analogues of anandamide, viz., 2-arachidonyl glycerol, arachidonyl dopamine, 2-arachidonyl glycerol ether (noladin ether), and o-arachidonyl ethanolamide (virodhamine). Molecular modeling of the five endocannabinoid lipids indicates that the highly unsaturated arachidonyl chain has a preferencemore » for a U or J shaped conformation. Thermal phase studies of the neat amphiphiles showed that a glass transition was observed for all of the endocannabinoids at {approx} -110 C with the exception of anandamide, with a second glass transition occurring for 2-arachidonyl glycerol, 2-arachidonyl glycerol ether, and virodhamine (-86 C, -95 C, -46 C respectively). Both anandamide and arachidonyl dopamine displayed a crystal-isotropic melting point (-4.8 and -20.4 C respectively), while a liquid crystal-isotropic melting transition was seen for 2-arachidonyl glycerol (-40.7 C) and 2-arachidonyl glycerol ether (-71.2 C). No additional transitions were observed for virodhamine. Small angle X-ray scattering and cross polarized optical microscopy studies as a function of temperature indicated that in the presence of excess water, both 2-arachidonyl glycerol and anandamide form co-existing Q{sub II}{sup G} (gyroid) and Q{sub II}{sup D} (diamond) bicontinuous cubic phases from 0 C to 20 C, which are kinetically stable over a period of weeks but may not represent true thermodynamic equilibrium. Similarly, 2-arachidonyl glycerol ether acquired an inverse hexagonal (HII) phase in excess water from 0 C to 40 C, while virodhamine and arachidonyl dopamine exist as an isotropic L{sub 2} phase, even at very low temperatures. Due to their preferential conformation and lipid self-assembly behaviour, all five endocannabinoids constitute high curvature lipids that can impart membrane stress within a cell membrane which has been linked to a number of membrane and membrane protein associated processes.« less

Kinetics and Pathways for the Debromination of Polybrominated Diphenyl Ethers by Bimetallic and Nanoscale Zerovalent Iron: Effects of Particle Properties and Catalyst

PubMed Central

Zhuang, Yuan; Jin, Luting; Luthy, Richard G.

2012-01-01

Polybrominated diphenyl ethers (PBDEs) are recognized as a new class of widely-distributed and persistent contaminants for which effective treatment and remediation technologies are needed. In this study, two kinds of commercially available nanoscale Fe° slurries (Nanofer N25 and N25S), a freeze-dried laboratory-synthesized Fe° nanoparticle (nZVI), and their palladized forms were used to investigate the effect of particle properties and catalyst on PBDE debromination kinetics and pathways. Nanofers and their palladized forms were found to debrominate PBDEs effectively. The laboratory-synthesized Fe° nanoparticles also debrominated PBDEs, but were slower due to deactivation by the freeze-drying and stabilization processes in the laboratory synthesis. An organic modifier, polyacrylic acid (PAA), bound on N25S slowed PBDE debromination by a factor of three to four compared to N25. The activity of palladized nZVI (nZVI/Pd) was optimized at 0.3 Pd/Fe wt% in our system. N25 could debrominate selected environmentally-abundant PBDEs, including BDE 209, 183, 153, 99, and 47, to end products di-BDEs, mono-BDEs and diphenyl ether (DE) in one week, while nZVI/Pd (0.3 Pd/Fe wt%) mainly resulted in DE as a final product. Step-wise major PBDE debromination pathways by unamended and palladized Fe° are described and compared. Surface precursor complex formation is an important limiting factor for palladized Fe° reduction as demonstrated by PBDE pathways where steric hindrance and rapid sequential debromination of adjacent bromines play an important role. PMID:22732301

Saint, Sinner, or Soldier - Liberation Theology and Low Intensity Conflict

DTIC Science & Technology

1991-12-17

wing 71 extremist. The rise of Liberation Theology in Guatemala received its momentum from the Maryknoll’s Cursillos de Capacitacion . This program...34Guatemala," pp. 312-313. 71. Summarized from Ibid, p. 313. 72. Information on the Cursillos de Capacitacion and the quote were taken from Michael

Novel and High Volume Use Flame Retardants in US Couches Reflective of the 2005 PentaBDE Phase Out

PubMed Central

2012-01-01

California’s furniture flammability standard Technical Bulletin 117 (TB 117) is believed to be a major driver of chemical flame retardant (FR) use in residential furniture in the United States. With the phase-out of the polybrominated diphenyl ether (PBDE) FR mixture PentaBDE in 2005, alternative FRs are increasingly being used to meet TB 117; however, it was unclear which chemicals were being used and how frequently. To address this data gap, we collected and analyzed 102 samples of polyurethane foam from residential couches purchased in the United States from 1985 to 2010. Overall, we detected chemical flame retardants in 85% of the couches. In samples purchased prior to 2005 (n = 41) PBDEs associated with the PentaBDE mixture including BDEs 47, 99, and 100 (PentaBDE) were the most common FR detected (39%), followed by tris(1,3-dichloroisopropyl) phosphate (TDCPP; 24%), which is a suspected human carcinogen. In samples purchased in 2005 or later (n = 61) the most common FRs detected were TDCPP (52%) and components associated with the Firemaster550 (FM 550) mixture (18%). Since the 2005 phase-out of PentaBDE, the use of TDCPP increased significantly. In addition, a mixture of nonhalogenated organophosphate FRs that included triphenyl phosphate (TPP), tris(4-butylphenyl) phosphate (TBPP), and a mix of butylphenyl phosphate isomers were observed in 13% of the couch samples purchased in 2005 or later. Overall the prevalence of flame retardants (and PentaBDE) was higher in couches bought in California compared to elsewhere, although the difference was not quite significant (p = 0.054 for PentaBDE). The difference was greater before 2005 than after, suggesting that TB 117 is becoming a de facto standard across the U.S. We determined that the presence of a TB 117 label did predict the presence of a FR; however, lack of a label did not predict the absence of a flame retardant. Following the PentaBDE phase out, we also found an increased number of flame retardants on the market. Given these results, and the potential for human exposure to FRs, health studies should be conducted on the types of FRs identified here. PMID:23186002

Protein dynamics in organic media at varying water activity studied by molecular dynamics simulation.

PubMed

Wedberg, Rasmus; Abildskov, Jens; Peters, Günther H

2012-03-01

In nonaqueous enzymology, control of enzyme hydration is commonly approached by fixing the thermodynamic water activity of the medium. In this work, we present a strategy for evaluating the water activity in molecular dynamics simulations of proteins in water/organic solvent mixtures. The method relies on determining the water content of the bulk phase and uses a combination of Kirkwood-Buff theory and free energy calculations to determine corresponding activity coefficients. We apply the method in a molecular dynamics study of Candida antarctica lipase B in pure water and the organic solvents methanol, tert-butyl alcohol, methyl tert-butyl ether, and hexane, each mixture at five different water activities. It is shown that similar water activity yields similar enzyme hydration in the different solvents. However, both solvent and water activity are shown to have profound effects on enzyme structure and flexibility.

Analysis of free and bound chlorophenoxy acids in cereals.

PubMed

Lokke, H

1975-06-01

Extraction of the chlorophenoxy acids 2,4-D and dichlorprop in cereals has been examined by analyzing barley from spraying experiments. A procedure has been set up by combination of acid hydrolysis and enzymatic degradation followed by extraction and clean up on either silica gel or basic aluminum oxide. The final determination is based on reaction with diazomethane and subsequently GLC with ECD. This procedure was compared with two different extraction procedures previously described in the literature. The one comparative procedure uses a mixture of 50% diethyl ether/hexane in presence of sulphuric acid and resulted in residues up to ten times lower than found after the combined acid hydrolysis/enzymatic degradation procedure. In the second comparison a direct extraction was made with a mixture of 65% (v/v) acetonitrile in water. No differences were found between this and the combined acid hydrolysis/enzymatic degradation procedure.

Interactive mixture of inhomogeneous dark fluids driven by dark energy: a dynamical system analysis

NASA Astrophysics Data System (ADS)

Izquierdo, Germán; Blanquet-Jaramillo, Roberto C.; Sussman, Roberto A.

2018-03-01

We examine the evolution of an inhomogeneous mixture of non-relativistic pressureless cold dark matter (CDM), coupled to dark energy (DE) characterised by the equation of state parameter w<-1/3, with the interaction term proportional to the DE density. This coupled mixture is the source of a spherically symmetric Lemaître-Tolman-Bondi (LTB) metric admitting an asymptotic Friedman-Lemaître-Robertson-Walker (FLRW) background. Einstein's equations reduce to a 5-dimensional autonomous dynamical system involving quasi-local variables related to suitable averages of covariant scalars and their fluctuations. The phase space evolution around the critical points (past/future attractors and five saddles) is examined in detail. For all parameter values and both directions of energy flow (CDM to DE and DE to CDM) the phase space trajectories are compatible with a physically plausible early cosmic times behaviour near the past attractor. This result compares favourably with mixtures with interaction driven by the CDM density, whose past evolution is unphysical for DE to CDM energy flow. Numerical examples are provided describing the evolution of an initial profile that can be associated with idealised structure formation scenarios.

Investigation of alternative organic solvents and methods for the preparation of long-circulating and pH-sensitive liposomes containing cisplatin.

PubMed

Giuberti, Cristiane dos Santos; Boratto, Fernanda Alves; Degobert, Ghania; Silveira, Josianne Nicácio; Oliveira, Mônica Cristina

2013-09-01

Recent studies using long-circulating and pH-sensitive liposomes containing cisplatin (SpHL-CDDP) have resulted in a formulation with improved pharmacokinetic, toxicity and tumor localization properties. In this study, SpHL-CDDP were prepared in both laboratory and pilot scales. This study evaluated the possibility of using the dehydration-rehydration method, as well as using alternative organic solvents (ethyl acetate/ethanol mixtures at 2:1 and 1:1 volume ratios), for the preparation of liposomes by the reverse-phase evaporation (REV) method. The influence of different concentrations of cisplatin (CDDP) (2.0, 1.0, 0.5 and 0.25 mg/mL) on the entrapment percentage and size of SpHL-CDDP was also investigated. In addition, carbohydrates were tested as cryoprotectants in a freeze-thaw study as a pretest to screen the type to be used in the freeze-drying process. A decrease in the encapsulation percentage of CDDP and an increase in the vesicle diameter could be observed for both liposome formulations prepared with ethyl acetate:ethanol mixtures, as compared with REV liposomes prepared with ethyl ether. It is important to note that after applying either quick or slow cooling, the mean diameter of SpHL (empty liposomes) proved to be similar when in the presence of cryoprotectants. In sum, the optimal processing conditions were achieved when using a 0.5 mg/mL CDDP solution, ethyl ether and the REV method, resulting in liposomal dispersions of mean diameters and homogeneities that were deemed suitable for intravenous administration.

Determining the presence of dipropylene glycol n-butyl ether (DPnB) in sediments and sands contaminated by the Deepwater Horizon (DWH) oil spill

NASA Astrophysics Data System (ADS)

Boehman, B.; Lyons, S. L.; Geng, Z.; White, H. K.

2016-02-01

In an attempt to mitigate the impact of the oil released from the Deepwater Horizon (DWH) oil spill, chemical dispersants (Corexit 9527 and Corexit 9500A, from Nalco Co.) were applied to the surface and subsurface waters of the Gulf of Mexico. Over the past five years studies have investigated the fate of oil from the spill and the applied dispersants, although significantly less is known about the latter. To determine the presence of dispersant in environmental samples, dioctyl sodium sulfosuccinate (DOSS), a component of both Corexit mixtures, has previously been examined in samples taken from the water column, coastal beaches and deep-sea sediments. This study expands upon this work by developing a method to extract dipropylene glycol n-butyl ether (DPnB), an additional compound present in Corexit, from sand and sediment samples contaminated with oil from the DWH spill. Controls spiked with a known quantity of DPnB were extracted with a range of organic solvents of different polarities to optimize the extraction of DPnB. Total organic extracts were then subjected to silica gel chromatography to isolate DPnB from any oil that was co-extracted. All samples were concentrated prior to analysis via gas chromatography mass spectrometry (GC/MS) using selected ion monitoring (SIM). The analysis and quantification of DPnB, which has different chemical properties than DOSS, will provide additional insight into the mechanisms that control the fate of oil and dispersant mixtures in the marine environment.

Allergenic activity of an air-oxidized ethoxylated surfactant.

PubMed

Karlberg, Ann-Therese; Bodin, Anna; Matura, Mihaly

2003-11-01

Ethoxylated surfactants are used in household and industrial cleaners, topical pharmaceuticals, cosmetics and laundry products. Polyethers, e.g. ethoxylated surfactants and polyethylene glycols, are oxidized by atmospheric oxygen (autoxidized) when stored and handled. We have previously shown that a chemically well-defined non-ionic surfactant, the ethoxylated alcohol penta-ethylene glycol mono-n-dodecyl ether (C12E5), forms a complex mixture of autoxidation products when exposed to air. Predictive testing in guinea pigs showed that the surfactant itself is a non-sensitizer, but that oxidation products formed are skin sensitizers. The aim of this study was to investigate the sensitizing capacity of a total oxidation mixture of C12E5 obtained after autoxidation. The allergenic activity of different oxidation products is discussed as well as the clinical importance of the findings. This study shows that the non-ionic surfactant C12E5 containing 20% oxidation products is a sensitizing mixture. The result accords with what is observed for other compounds that are unstable when in contact with air, e.g. limonene and linalool, major fragrance terpenes. Studies regarding the clinical relevance of our findings should be performed. However, it is already clear from this study that precautions must be taken in handling and storage of ethoxylated surfactants to avoid formation of allergenic mixtures.

Anaerobic degradation of a mixture of MtBE, EtBE, TBA, and benzene under different redox conditions.

PubMed

van der Waals, Marcelle J; Pijls, Charles; Sinke, Anja J C; Langenhoff, Alette A M; Smidt, Hauke; Gerritse, Jan

2018-04-01

The increasing use of biobased fuels and fuel additives can potentially change the typical fuel-related contamination in soil and groundwater. Anaerobic biotransformation of the biofuel additive ethyl tert-butyl ether (EtBE), as well as of methyl tert-butyl ether (MtBE), benzene, and tert-butyl alcohol (TBA, a possible oxygenate metabolite), was studied at an industrially contaminated site and in the laboratory. Analysis of groundwater samples indicated that in the field MtBE was degraded, yielding TBA as major product. In batch microcosms, MtBE was degraded under different conditions: unamended control, with medium without added electron acceptors, or with ferrihydrite or sulfate (with or without medium) as electron acceptor, respectively. Degradation of EtBE was not observed under any of these conditions tested. TBA was partially depleted in parallel with MtBE. Results of microcosm experiments with MtBE substrate analogues, i.e., syringate, vanillate, or ferulate, were in line with the hypothesis that the observed TBA degradation is a cometabolic process. Microcosms with ferulate, syringate, isopropanol, or diethyl ether showed EtBE depletion up to 86.5% of the initial concentration after 83 days. Benzene was degraded in the unamended controls, with medium without added electron acceptors and with ferrihydrite, sulfate, or chlorate as electron acceptor, respectively. In the presence of nitrate, benzene was only degraded after addition of an anaerobic benzene-degrading community. Nitrate and chlorate hindered MtBE, EtBE, and TBA degradation.

Solid-phase extraction clean-up of ciguatoxin-contaminated coral fish extracts for use in the mouse bioassay.

PubMed

Wong, Chun Kwan; Hung, Patricia; Lee, Kellie L H; Kam, Kai Man

2009-02-01

Florisil solid-phase extraction (SPE) cartridges were used for purifying ciguatoxin (CTX)-contaminated coral fish extracts, with the aim of removing extracted lipid but retaining optimal level of CTXs in the purified fractions. The CTX-containing fraction (target fraction) in fish ether extract was isolated and purified by eluting through a commercially available Florisil cartridge with hexane-acetone-methanol solvent mixtures of increasing polarity (hexane-acetone (4:1, v/v) < acetone-methanol (7:3, v/v) < 100% methanol). Application of Florisil SPE using acetone-methanol (7:3, v/v) condition facilitated the separation of 4.2 +/- 0.4 mg (mean +/- standard error of the mean (SEM)) of purified target fraction from 20 mg ether extract with good retention of CTXs. The mouse bioassay was used to demonstrate that the average CTX recovery of the target fraction from CTX-spiked samples was 75.8% +/- 3.3%, which was significantly increased by 96.7% +/- 15% when compared with CTX recovery from ether extracts (44.8% +/- 5.2%) without performing SPE purification. Over 70% of non-target lipids were removed in which no CTX toxicity was found. Moreover, the target fractions of both CTX-spiked and naturally CTX-contaminated samples gave more prominent toxic responses of hypothermia and/or induced more rapid death of the mice. The use of acetone-methanol (7:3, v/v) condition in the elution could significantly improve overall recovery of CTXs, while minimizing the possible interferences of lipid matrix from co-extractants on mice.

Formation of polychlorinated diphenyl ethers from condensation of chlorophenols with chlorobenzenes.

PubMed

Liu, Wenxia; Zheng, Minghui; Liu, Wenbin; Ma, Xiaodong; Qian, Yong; Zhang, Bing

2008-01-01

Polychlorinated diphenyl ethers (PCDEs), which are among the members of persistent organic pollutants, and PCDEs have been determined in a number of environmental samples. The main possible sources are the technical production of chlorinated phenols and all processes of incomplete combustion. PCDEs were observed in the fly ash from a municipal waste incinerator (MWI). It was speculated that the condensation of chlorophenols with chlorobenzenes occurred via PCDEs to form polychlorinated dibenzofurans (PCDFs). Nevertheless, PCDEs formation from condensation of chlorophenols with chlorobenzenes has not been confirmed by experimental observation. The objective of this paper is to investigate the formation mechanism of PCDEs from the condensation of chlorophenols with chlorobenzenes. The results are expected to be helpful in understanding the formation of PCDEs and in controlling and abating PCDEs emissions from MWI. The pyrolysis of pentachlorophenol (PCP) and/or polychlorobenzenes (PCBz) was carried out in a sealed glass tube. The reaction products were extracted and purified with K2CO3 solution. The samples were concentrated and then cleaned up on an alumina column. GC/MS was used for identification and quantification of reaction products. The results showed that the pyrolysis of hexachlorobenzene (HCB) at 340 degrees C for 6 h led to the formation of decachlorodiphenyl ether (DCDE) (2.41 microg/mg) and octachlorodibenzo-p-dioxins (OCDD) (0.24 micropg/mg), while the pyrolysis of PCP yielded DCDE (13.08 microg/mg) and OCDD (180.13 microg/mg). In addition, the amount of DCDE formation from the pyrolysis of the mixture of PCP and HCB was 4.65 times higher than the total amount of DCDE formation from the pyrolysis of HCB and PCP, respectively. This indicated that PCP and HCB were prone to condensation and formation of DCDE. DCDE was the main congener of PCDEs from condensation of PCP with HCB at 340, 400 and 450 degrees C. A small amount of nonachlorodiphenyl ether (NCDE) was formed by dechlorination reaction at 450 degrees C. The condensation of PCP with 1,2,4,5-tetrachlorobenzene (Cl4Bz) formed 2,2',3,4,4',5,5',6-octachlorodiphenyl ether (OCDE). Small amounts of heptachlorodiphenyl ether (HpCDE) and hexachlorodiphenyl ether (HxCDE) were detected at 450 degrees C. Meanwhile, polychlorinated dibenzo-p-dioxins (PCDDs) and PCDFs were detected from the condensation of PCP and PCBz. Experimental studies clarified the behavior of the formation of PCDEs from condensation of polychlorophenols and PCBz. The condensation of polychlorophenols with PCBz formed PCDEs through elimination of HCl between polychlorophenols and PCBz molecules. Another pathway of PCDEs formation was elimination of H2O between two polychlorophenol molecules. In addition, dechlorination processes had caused the specific homologous pattern of PCDEs under higher temperatures.

The accuracy of formol-ether concentration in diagnosing soiltransmitted helminths in elementary school 27 Peusangan in Bireuen

NASA Astrophysics Data System (ADS)

Fitriani, C. L.; Panggabean, M.; Pasaribu, A. P.

2018-03-01

Soil-transmitted helminths (STH) or a group of parasitic nematode worms causing human infection through contact with moist soil may contribute to anemia, nutritional disorders, physical and intellectual growth retardation. School-age children are at high risk of STH infection due to frequent contact with soil. Reliable, sensitive, and practical diagnostic are the test series for detecting STH. This study aimed to assess the sensitivity and specificity of the formol-ether concentration (FEC) in the diagnosis of STH when compared to the Kato-Katz technique. The study was designed at state elementary school 27 Peusangan, Bireuen. The FEC study on a total of 80 (100%) elementary students showed that 12 (15%) sample had the STH infection, while Kato-Katz technique (Gold standard) showed that 31 (38.75%) sample had the STH infection. The FEC technique has the sensitivity of (38.71%), specificity of (100%) and accuracy of (76.25%). The Kato-Katz technique is better than the FEC technique for assessing STH in Bireuen due to mild infection.

Non Covalent Interactions in Large Diamondoid Dimers in the Gas Phase - a Microwave Study

NASA Astrophysics Data System (ADS)

Perez, Cristobal; Sekutor, Marina; Fokin, Andrey A.; Blomeyer, Sebastian; Vishnevskiy, Yury V.; Mitzel, Norbert W.; Schreiner, Peter R.; Schnell, Melanie

2017-06-01

Accurate structure determination of large molecules still represents an ambitious challenge. Interesting benchmark systems for structure determination are large diamondoid dimers, whose structures are governed by strong intramolecular interactions. Recently, diamondoid dimers with unusually long central C-C bonds (up to 1.71 Å) were synthesized. This long central C-C bond was rationalized by numerous CH...HC-type dispersion attractions between the two halves of the molecule. The thermodynamic stabilization of molecules equipped with bulky groups has provided a conceptually new rationale, since until then it had been assumed that such molecules are highly unstable. We performed a broadband CP-FTMW spectroscopy study in the 2-8 GHz frequency range on oxygen-substituted diamondoid dimers (C_{26}H_{34}O_2, 28 heavy atoms) as well as diadamantyl ether to provide further insight into their structures. The experimental data are compared with results from quantum-chemical calculations and gas-phase electron diffraction. For the ether, we even obtained ^{13}C and ^{18}O isotopologues to generate the full heavy-atom substitution structure.

Studies on effects of Andrographis paniculata (Burm.f.) and Andrographis lineata nees (Family: Acanthaceae) extracts against two mosquitoes Culex quinquefasciatus (Say.) and Aedes aegypti (Linn.).

PubMed

Renugadevi, G; Ramanathan, T; Shanmuga, priya R; Thirunavukkarasu, P

2013-03-01

To investigate the studies on effects of Andrographis paniculata (A. paniculata) (Burm.f.) and Andrographis lineata (A. lineata) nees (Family: Acanthaceae) extracts against two mosquitoes Culex quinquefasciatus (Cx. quinquefasciatus) (Say.) and Aedes aegypti (Ae. aegypti) (Linn.). The aqueous and petroleum ether extracts of two plant species, A. paniculata and A. lineate were examined against the larvae of A. aegypti (L.) and Cx. quinquefasciatus with gradually increasing concentration ie. from 50 to 200 ppm of solvent extracts and to test their activity in combination with each other. In a 24 h bioassay experiment with plant extracts, highest mortalities were recorded at 200 ppm of concentrations for leaves of A. lineta and A. paniculata individually. For combination effect, only 150 ppm of the mixture of solvent extracts of petroleum ether: aqueous (1:1) extracts showed 100% mortality after 24 h of exposure. The results show that, insecticides of plant combination is ecofriend and has better larvicidal activity compared to individual extracts. Copyright © 2013 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Volatiles from a rare Acer spp. honey sample from Croatia.

PubMed

Jerković, Igor; Marijanović, Zvonimir; Malenica-Staver, Mladenka; Lusić, Drazen

2010-06-24

A rare sample of maple (Acer spp.) honey from Croatia was analysed. Ultrasonic solvent extraction (USE) using: 1) pentane, 2) diethyl ether, 3) a mixture of pentane and diethyl ether (1:2 v/v) and 4) dichloromethane as solvents was applied. All the extracts were analysed by GC and GC/MS. The most representative extracts were 3) and 4). Syringaldehyde was the most striking compound, being dominant in the extracts 2), 3) and 4) with percentages 34.5%, 33.1% and 35.9%, respectively. In comparison to USE results of other single Croatian tree honey samples (Robinia pseudoacacia L. nectar honey, Salix spp. nectar and honeydew honeys, Quercus frainetto Ten. honeydew as well as Abies alba Mill. and Picea abies L. honeydew) and literature data the presence of syringaldehyde, previously identified in maple sap and syrup, can be pointed out as a distinct characteristic of the Acer spp. honey sample. Headspace solid-phase microextraction (HS-SPME) combined with GC and GC/MS identified benzaldehyde (16.5%), trans-linalool oxide (20.5%) and 2-phenylethanol (14.9%) as the major compounds that are common in different honey headspace compositions.

New Ether-functionalized Morpholinium- and Piperidinium-based Ionic Liquids as Electrolyte Components in Lithium and Lithium-Ion Batteries.

PubMed

Navarra, Maria Assunta; Fujimura, Kanae; Sgambetterra, Mirko; Tsurumaki, Akiko; Panero, Stefania; Nakamura, Nobuhumi; Ohno, Hiroyuki; Scrosati, Bruno

2017-06-09

Here, two ionic liquids, N-ethoxyethyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide (M 1,2O2 TFSI) and N-ethoxyethyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide (P 1,2O2 TFSI) were synthesized and compared. Fundamental relevant properties, such as thermal and electrochemical stability, density, and ionic conductivity were analyzed to evaluate the effects caused by the presence of the ether bond in the side chain and/or in the organic cation ring. Upon lithium salt addition, two electrolytes suitable for lithium batteries applications were found. Higher conducting properties of the piperidinium-based electrolyte resulted in enhanced cycling performances when tested with LiFePO 4 (LFP) cathode in lithium cells. When mixing the P 1,2O2 TFSI/LiTFSI electrolyte with a tailored alkyl carbonate mixture, the cycling performance of both Li and Li-ion cells greatly improved, with prolonged cyclability delivering very stable capacity values, as high as the theoretical one in the case of Li/LFP cell configurations. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Experimental and DFT study of cyclodehydration and acetylation of ferrocenyl diols

NASA Astrophysics Data System (ADS)

Lapić, Jasmina; Višnjevac, Aleksandar; Cetina, Mario; Djaković, Senka; Vrček, Valerije; Rapić, Vladimir

2012-07-01

Racemic ferrocenyl diols, i.e. ferrocenyl(2-hydroxymethylphenyl)methanol (2), ferrocenyl-2-(2-hydroxymethylphenyl)ethanol (7), and ferrocenyl(2-(2-hydroxyethyl)phenyl)methanol (9) have been prepared by reduction of corresponding ketoesters using NaBH4 in a mixture EtOH and Et2O. In the course of these reactions new cyclic ethers 1-ferrocenyl-2-oxaindane (3), 3-ferrocenylisochromane (8), and 1-ferrocenylisochromane (10) have been isolated as side-products. Intramolecular cyclizations of ferrocenyl diols occur in both acidic and neutral medium. Density functional theory (BP86) calculations were used to explain the mechanism of these cyclodehydrations. Acid catalyzed reaction follows the classical SN1 mechanism, whereas the cyclodehydration in neutral medium is described as an SN2 reaction. X-ray diffraction analysis of new cyclic ether products has been performed. Monoacetates 11, 13 and 15 have been obtained in the reaction of ferrocenyl diols 2, 7, and 9, respectively, and acetic anhydride. Stereoselective acylation of racemic diols by vinyl acetate have been catalyzed by various lipases, and the best stereoselectivity has been observed for the diol 2 in the presence of Penicillium camembertii lipase.

Seasonal variability of polychlorinated biphenyls (PCBs) and polychlorinated diphenyl ethers (PBDEs) congener profiles in butter in Poland: dietary risk evaluation.

PubMed

Roszko, Marek; Szymczyk, Krystyna; Rzepkowska, Małgorzata; Jędrzejczak, Renata

2014-01-01

Various statistical methods have been employed to analyse in details seasonal diversification of polychlorinated biphenyl (PCB)/polybrominated diphenyl ether (PBDE) congener profiles found in butter fat. The variability of the PCB/PBDE congener profiles indicates the presence of various sources of the milk fat contamination. The obtained results suggest that the environmental chemical background has the highest share in the contamination sources pattern. Ion trap mass spectrometry coupled to high-resolution gas chromatography with semi-permeable membrane dialysis sample cleanup was used for determination of PCBs and PBDEs in milk fat. Determined butter fat PCB profiles were similar to the profiles characteristic for Aroclor 1254 technical mixture. Our data indicate that dietary intake of PCB/PBDE with milk and milk products may be estimated to be about 717.5 pg kg b.w.(-1) day(-1) for six-indicator PCBs, 0.329 (equivalent toxicity, TEQ) pg kg b.w.(-1) day(-1) for 12 DL PCBs and 50 pg kg b.w.(-1) day(-1) for PBDEs (sum of 14 congeners).

Deteriorated glucose metabolism with a high-protein, low-carbohydrate diet in db mice, an animal model of type 2 diabetes, might be caused by insufficient insulin secretion.

PubMed

Arimura, Emi; Pulong, Wijang Pralampita; Marchianti, Ancah Caesarina Novi; Nakakuma, Miwa; Abe, Masaharu; Ushikai, Miharu; Horiuchi, Masahisa

2017-02-01

We previously showed the deleterious effects of increased dietary protein on renal manifestations and glucose metabolism in leptin receptor-deficient (db) mice. Here, we further examined its effects on glucose metabolism, including urinary C-peptide. We also orally administered mixtures corresponding to low- or high-protein diets to diabetic mice. In diet experiments, under pair-feeding (equivalent energy and fat) conditions using a metabolic cage, mice were fed diets with different protein content (L diet: 12 % protein, 71 % carbohydrate, 17 % fat; H diet: 24 % protein, 59 % carbohydrate, 17 % fat) for 15 days. In oral administration experiments, the respective mixtures (L mixture: 12 % proline, 71 % maltose or starch, 17 % linoleic acid; H mixture: 24 % proline, 59 % maltose or starch, 17 % linoleic acid) were supplied to mice. Biochemical parameters related to glucose metabolism were measured. The db-H diet mice showed significantly higher water intake, urinary volume, and glucose levels than db-L diet mice but similar levels of excreted urinary C-peptide. In contrast, control-H diet mice showed significantly higher C-peptide excretion than control-L diet mice. Both types of mice fed H diet excreted high levels of urinary albumin. When maltose mixtures were administered, db-L mixture mice showed significantly higher blood glucose after 30 min than db-H mixture mice. However, db mice administered starch-H mixture showed significantly higher blood glucose 120-300 min post-administration than db-L mixture mice, although both groups exhibited similar insulin levels. High-protein, low-carbohydrate diets deteriorated diabetic conditions and were associated with insufficient insulin secretion in db mice. Our findings may have implications for dietary management of diabetic symptoms in human patients.

High-Performance Polymers Having Low Melt Viscosities

NASA Technical Reports Server (NTRS)

Jensen, Brian J.

2005-01-01

High-performance polymers that have improved processing characteristics, and a method of making them, have been invented. One of the improved characteristics is low (relative to corresponding prior polymers) melt viscosities at given temperatures. This characteristic makes it possible to utilize such processes as resin-transfer molding and resin-film infusion and to perform autoclave processing at lower temperatures and/or pressures. Another improved characteristic is larger processing windows that is, longer times at low viscosities. Other improved characteristics include increased solubility of uncured polymer precursors that contain reactive groups, greater densities of cross-links in cured polymers, improved mechanical properties of the cured polymers, and greater resistance of the cured polymers to chemical attack. The invention is particularly applicable to poly(arylene ether)s [PAEs] and polyimides [PIs] that are useful as adhesives, matrices of composite materials, moldings, films, and coatings. PAEs and PIs synthesized according to the invention comprise mixtures of branched, linear, and star-shaped molecules. The monomers of these polymers can be capped with either reactive end groups to obtain thermosets or nonreactive end groups to obtain thermoplastics. The synthesis of a polymeric mixture according to the invention involves the use of a small amount of a trifunctional monomer. In the case of a PAE, the trifunctional monomer is a trihydroxy- containing compound for example, 1,3,5-trihydroxybenzene (THB). In the case of a PI, the trifunctional monomer is a triamine for example, triamino pyrimidine or melamine. In addition to the aforementioned trifunctional monomer, one uses the difunctional monomers of the conventional formulation of the polymer in question (see figure). In cases of nonreactive end caps, the polymeric mixtures of the invention have melt viscosities and melting temperatures lower than those of the corresponding linear polymers of equal molecular weights. The lower melting temperatures and melt viscosities provide larger processing windows. In cases of reactive end caps, the polymeric mixtures of the invention have lower melt viscosities before curing and the higher cross-link densities after curing (where branching in the uncured systems would become cross-links in the cured systems), relative to the corresponding linear polymers of equal molecular weights. The greater cross-link densities afford increased resistance to chemical attack and improved mechanical properties.

Photopyroelectric response of PTCa∕PEEK composite.

PubMed

Estevam, Giuliano Pierre; de Melo, Washington Luiz Barros; Sakamoto, Walter Katsumi

2011-02-01

A pyroelectric composite made of calcium modified lead titanate ceramic and polyether-ether-ketone high performance polymer was obtained in the film form by hot pressing the ceramic/polymer mixture into the desired composition. After polarization with a suitable electric field, a ceramic composite film (60% vol.) exhibited a pyroelectric figure of merit three times higher than that of a lead zirconate titanate ceramic. The material was used as infrared radiation sensor. The voltage responsivity decreases with the inverse of the frequency showing the same behavior of the thermally thick sensor. The reproducibility of the sensor responses was observed.

Genetic Exclusion in Bacteriophage T4.

DTIC Science & Technology

1987-01-01

1942) as "interference" between various coliphages , was shown by Delbruck and Bailey (1946) to be the inability of superinfecting phage to contribute... water : 5.8 g Na IPO , 3.0 2 4 g KH PO , 0.5 g NaCl, 1.0 g NH Cl, and the pH adjusted to 2 4 4 o 6.8 to 7.0. All media were autoclaved, cooled to 55 C...0.5M Tris), once with a 1:1 mixture of phenol and chloroform (1/24 isoamyl alcohol) then thrice iith an equal volume of water saturated ether. After

Production of chemicals and fuels from biomass

DOEpatents

Woods, Elizabeth; Qiao, Ming; Myren, Paul; Cortright, Randy D.; Kania, John

2015-12-15

Described are methods, reactor systems, and catalysts for converting biomass to fuels and chemicals in a batch and/or continuous process. The process generally involves the conversion of water insoluble components of biomass, such as hemicellulose, cellulose and lignin, to volatile C.sub.2+O.sub.1-2 oxygenates, such as alcohols, ketones, cyclic ethers, esters, carboxylic acids, aldehydes, and mixtures thereof. In certain applications, the volatile C.sub.2+O.sub.1-2 oxygenates can be collected and used as a final chemical product, or used in downstream processes to produce liquid fuels, chemicals and other products.

Parental exposure to natural mixtures of persistent organic pollutants (POP) induced changes in transcription of apoptosis-related genes in offspring zebrafish embryos.

PubMed

Lyche, Jan L; Grześ, Irena M; Karlsson, Camilla; Nourizadeh-Lillabadi, Rasoul; Aleström, Peter; Ropstad, Erik

2016-01-01

Apoptosis is an integral element of development that may also be initiated by environmental contaminants. The aim of the present study was to assess potential changes in the regulation of apoptotic genes in zebrafish embryos following parental exposure to two natural mixtures of persistent organic pollutants (POP). The mixture from Lake Mjøsa contained exceptionally high concentrations of polybrominated diphenyl ethers (PBDE), as well as relatively high levels of polychlorinated biphenyls (PCB) and dichlorodiphenyltrichloroethane (DDT). The mixture from Lake Losna contained background concentrations of POP. Genes involved in the apoptotic machinery were screened for their expression profile at four time points during embryonic development. Thirteen and 15 genes involved in apoptosis were found to be significantly upregulated in the high-exposure and background exposure groups, respectively, compared with controls. Modulation of apoptotic genes was restricted only to the first time point, which corresponds with the blastula stage. Although there were substantial differences in POP concentrations between mixtures, genes underlying the apoptosis process showed almost similar responses to the two mixtures. In both exposure groups the main executors of apoptosis p53, casp 2, casp 6, cassp 8, and BAX displayed upregulation compared to controls, suggesting that these POP induce apoptosis via a p53-dependent mechanism. Upregulation of genes that play a critical role in apoptosis suggests that disturbance of normal apoptotic signaling during gametogenesis and embryogenesis may be one of the central mechanisms involved in adverse reproductive effects produced by POP in zebrafish.

Proprietes ionochromes et photochromes de derives du polythiophene

NASA Astrophysics Data System (ADS)

Levesque, Isabelle

La synthese et la caracterisation de derives regioreguliers du polythiophene ont ete effectuees en solution et sur des films minces. La spectroscopie UV-visible de ces derives a permis de constater qu'ils peuvent posseder des proprietes chromiques particulieres selon le stimulus auquel ils sont soumis. Par exemple, une augmentation de la temperature permet en effet aux polymeres de passer d'une couleur violette a jaune, et ce, a l'etat solide aussi bien qu'en solution. Ces proprietes chromiques semblent regies par une transition conformationnelle (plane a non-plane) de la chaine principale. Ce travail avait pour but de mieux comprendre l'influence de l'organisation des chaines laterales sur les transitions chromiques. Deux derives synthetises possedant des chaines laterales sensibles aux cations alcalins se sont averes etre ionochromes en plus d'etre thermochromes. Il s'agit d'un polymere comportant des chaines laterales de type oligo(oxyethylene) et d'un autre comportant un groupement ether couronne specifique aux ions lithium. Les effets chromiques observes sont expliques par des interactions non-covalentes des cations avec les atomes d'oxygene des chaines laterales dans le cas du premier polymere, et par l'insertion de l'ion Li + dans la cavite de l'ether couronne dans le cas du second polymere. Ces interactions semblent provoquer une diminution de l'organisation induisant ainsi une torsion de la chaine principale. Les deux polymeres semblent specifiques a certains cations et pourraient donc servir comme detecteurs optiques. La specificite aux ions Li+ du second polymere pourrait aussi permettre la conduction ionique, en plus de la conductivite electronique caracteristique des polythiophenes, ce qui pourrait s'averer utile dans le cas de batteries legeres entierement faites de polymeres et de sels de lithium. D'autres derives comportant des chaines laterales de type azobenzene se sont averes etre photochromes en plus d'etre thermochromes. Le groupement lateral a la possibilite de changer de configuration de la forme trans a la forme cis lorsqu'il est soumis a une irradiation dans le domaine de l'ultraviolet ce qui provoque, selon toute evidence, un effet marque sur l'organisation des chaines laterales. Cela induit alors une torsion de la chaine principale thiophene entrainant une diminution de conjugaison marquee. Ces effets peuvent etre exploites entre autres dans l'ecriture optique. Il s'est avere que le polymere irradie peu conjugue peut etre force a retourner a son etat initial conjugue tres rapidement par un traitement electrochimique simple. En conclusion, on a pu prouver qu'une modification dans l'organisation des chaines laterales par un stimulus exterieur affecte considerablement la conformation de la chaine principale. Cela porte a croire que les chaines laterales stabilisent une conformation particuliere des polythiophenes.

Lipid digestibility and energy content of distillers corn oil in swine and poultry

USDA-ARS?s Scientific Manuscript database

Two experiments were conducted to determine the DE and ME, and apparent total tract digestibility of ether extract of 3 distillers corn oil (DCO; 4.9, 12.8, or 13.9% FFA), compared with a sample of refined corn oil (CO, 0.04% FFA), and an industrially-hydrolyzed high FFA DCO (93.8% FFA) in young pig...

Posterior lumbar interbody fusion using non resorbable poly-ether-ether-ketone versus resorbable poly-L-lactide-co-D,L-lactide fusion devices. Clinical outcome at a minimum of 2-year follow-up.

PubMed

Jiya, Timothy U; Smit, T; van Royen, B J; Mullender, M

2011-04-01

Previous papers on resorbable poly-L-lactide-co-D,L-lactide (PLDLLA) cages in spinal fusion have failed to report adequately on patient-centred clinical outcome measures. Also comparison of PLDLLA cage with a traditionally applicable counterpart has not been previously reported. This is the first randomized prospective study that assesses clinical outcome of PLDLLA cage compared with a poly-ether-ether-ketone (PEEK) implant. Twenty-six patients were randomly assigned to undergo instrumented posterior lumbar interbody fusion (PLIF) whereby either a PEEK cage or a PLDLLA cage was implanted. Clinical outcome based on visual analogue scale scores for leg pain and back pain, as well as Oswestry Disability Index (ODI) and SF-36 questionnaires were documented and analysed. When compared with preoperative values, all clinical parameters have significantly improved in the PEEK group at 2 years after surgery with the exception of SF-36 general health, SF-36 mental health and SF-36 role emotional scores. No clinical parameter showed significant improvement at 2 years after surgery compared with preoperative values in the PLDLLA patient group. Only six patients (50%) in the PLDLLA group showed improvement in the VAS scores for leg and back pain as well as the ODI, as opposed to 10 patients (71%) in the PEEK group. One-third of the patients in the PLDLLA group actually reported worsening of their pain scores and ODI. Three cases of mild to moderate osteolysis were seen in the PLDLLA group. Following up on our preliminary report, these 2-year results confirm the superiority of the PEEK implant to the resorbable PLDLLA implant in aiding spinal fusion and alleviating symptoms following PLIF in patients with degenerative spondylolisthesis associated with either canal stenosis or foramen stenosis or both and emanating from a single lumbar segment.

Syntheses, Structures, and Binding Constants of Cyclic Ether and Thioether Adducts of Soluble Cadmium(II) Carboxylates. Intermediates in the Homopolymerization of Oxiranes and Thiiranes and in Carbon Dioxide Coupling Processes.

PubMed

Darensbourg, Donald J.; Niezgoda, Sharon A.; Holtcamp, Matthew W.; Draper, Jennifer D.; Reibenspies, Joseph H.

1997-05-21

A synthetic methodology for the preparation of a large variety of eta(3)-HB(3-Phpz)(3)Cd(acetate) adducts is presented which involves replacement of toluene in the eta(3)-HB(3-Phpz)(3)Cd(acetate) solvate complex by the appropriate cyclic ether or cyclic thioether. In this manner, adducts of THF, dioxane, propylene oxide, cyclohexene oxide, and propylene sulfide were isolated. The solid-state structures of several of these complexes were determined by X-ray crystallography, revealing a six-coordinate complex where the acetate ligand is shown to be fairly symmetrically bonded to the cadmium center. In methylene chloride solution, the cyclic ether or thioether readily dissociates to afford the five-coordinate complex, as demonstrated by (113)Cd NMR. A quantitative assessment of the binding of these base adducts of eta(3)-HB(3-Phpz)(3)Cd(acetate) was determined by measuring the temperature dependence of the equilibrium constants for the five- and six-coordinate derivatives. The presence of one sharp (113)Cd resonance in this equilibrium mixture is indicative of rapid intermolecular exchange between the five- and six-coordinate complexes when compared to the chemical shift differences in these two species ( approximately 6600 Hz at 89 MHz). The order established for ether binding is THF > dioxane > propylene sulfide > cyclohexene oxide >/= propylene oxide, with DeltaH degrees and DeltaS degrees spanning the ranges -27.7 to 24.3 kJ/mol and -89.7 to -94.1 J/(mol K). The epoxide and thioepoxide adducts were shown to serve as models for the initiation step in the copolymerization of epoxides with carbon dioxide catalyzed by metal carboxylates. That is, the carboxylate ligand was shown to ring-open the epoxide or thioepoxide, subsequently affording polyethers or polythioethers with ester end groups. By way of contrast, in the presence of CO(2) and epoxides, this system led to cyclic carbonate production.

Infrared spectra of complex organic molecules in astronomically relevant ice matrices. I. Acetaldehyde, ethanol, and dimethyl ether

NASA Astrophysics Data System (ADS)

Terwisscha van Scheltinga, J.; Ligterink, N. F. W.; Boogert, A. C. A.; van Dishoeck, E. F.; Linnartz, H.

2018-03-01

Context. The number of identified complex organic molecules (COMs) in inter- and circumstellar gas-phase environments is steadily increasing. Recent laboratory studies show that many such species form on icy dust grains. At present only smaller molecular species have been directly identified in space in the solid state. Accurate spectroscopic laboratory data of frozen COMs, embedded in ice matrices containing ingredients related to their formation scheme, are still largely lacking. Aim. This work provides infrared reference spectra of acetaldehyde (CH3CHO), ethanol (CH3CH2OH), and dimethyl ether (CH3OCH3) recorded in a variety of ice environments and for astronomically relevant temperatures, as needed to guide or interpret astronomical observations, specifically for upcoming James Webb Space Telescope observations. Methods: Fourier transform transmission spectroscopy (500-4000 cm-1/20-2.5 μm, 1.0 cm-1 resolution) was used to investigate solid acetaldehyde, ethanol and dimethyl ether, pure or mixed with water, CO, methanol, or CO:methanol. These species were deposited on a cryogenically cooled infrared transmissive window at 15 K. A heating ramp was applied, during which IR spectra were recorded until all ice constituents were thermally desorbed. Results: We present a large number of reference spectra that can be compared with astronomical data. Accurate band positions and band widths are provided for the studied ice mixtures and temperatures. Special efforts have been put into those bands of each molecule that are best suited for identification. For acetaldehyde the 7.427 and 5.803 μm bands are recommended, for ethanol the 11.36 and 7.240 μm bands are good candidates, and for dimethyl ether bands at 9.141 and 8.011 μm can be used. All spectra are publicly available in the Leiden Database for Ice.

Versatile solvent systems for the separation of betalains from processed Beta vulgaris L. juice using counter-current chromatography.

PubMed

Spórna-Kucab, Aneta; Ignatova, Svetlana; Garrard, Ian; Wybraniec, Sławomir

2013-12-15

Two mixtures of decarboxylated and dehydrogenated betacyanins from processed red beet roots (Beta vulgaris L.) juice were fractionated by high performance counter-current chromatography (HPCCC) producing a range of isolated components. Mixture 1 contained mainly betacyanins, 14,15-dehydro-betanin (neobetanin) and their decarboxylated derivatives while mixture 2 consisted of decarboxy- and dehydro-betacyanins. The products of mixture 1 arose during thermal degradation of betanin/isobetanin in mild conditions while the dehydro-betacyanins of mixture 2 appeared after longer heating of the juice from B. vulgaris L. Two solvent systems were found to be effective for the HPCCC. A highly polar, high salt concentration system of 1-PrOH-ACN-(NH4)2SO4 (satd. soln)-water (v/v/v/v, 1:0.5:1.2:1) (tail-to-head mode) enabled the purification of 2-decarboxy-betanin/-isobetanin, 2,17-bidecarboxy-betanin/-isobetanin and neobetanin (all from mixture 1) plus 17-decarboxy-neobetanin, 2,15,17-tridecarboxy-2,3-dehydro-neobetanin, 2-decarboxy-neobetanin and 2,15,17-tridecarboxy-neobetanin (from mixture 2). The other solvent system included heptafluorobutyric acid (HFBA) as ion-pair reagent and consisted of tert-butyl methyl ether (TBME)-1-BuOH-ACN-water (acidified with 0.7% HFBA) (2:2:1:5, v/v/v/v) (head-to-tail mode). This system enabled the HPCCC purification of 2,17-bidecarboxy-betanin/-isobetanin and neobetanin (from mixture 1) plus 2,15,17-tridecarboxy-2,3-dehydro-neobetanin, 2,17-bidecarboxy-2,3-dehydro-neobetanin and 2,15,17-tridecarboxy-neobetanin (mixture 2). The results of this research are crucial in finding effective isolation methods of betacyanins and their derivatives which are meaningful compounds due their colorant properties and potential health benefits regarding antioxidant and cancer prevention. The pigments were detected by LC-DAD and LC-MS/MS techniques. Copyright © 2013 Elsevier B.V. All rights reserved.

40 CFR Table 6 to Subpart Jj of... - VHAP of Potential Concern

Code of Federal Regulations, 2011 CFR

2011-07-01

... glycol butyl ether, ethylene glycol ethyl ether (2-ethoxy ethanol), ethylene glycol hexyl ether, ethylene..., ethylene glycol mono-2-ethylhexyl ether, diethylene glycol butyl ether, diethylene glycol ethyl ether... glycol propyl ether, triethylene glycol butyl ether, triethylene glycol ethyl ether, triethylene glycol...

Dimethyl Ether Between 214.6 and 265.3 Ghz: the Complete, Temperature Resolved Spectrum

NASA Astrophysics Data System (ADS)

McMillan, James P.; Neese, Christopher F.; De Lucia, Frank C.

2017-06-01

We have studied dimethyl ether, one of the so-called 'astronomical weeds', in the 214.6-265.3 GHz band. We have experimentally gathered a set of intensity calibrated, complete, and temperature resolved spectra from across the temperature range of 238-391 K. Using our previously reported method of analysis, the point by point method, we are capable of generating the complete spectrum at astronomically significant temperatures. Many lines, of nontrivial intensity, which were previously not included in the available astrophysical catalogs have been found. Lower state energies and line strengths have been found for a number of lines which are not currently present in the catalogs. The extent to which this may be useful in making assignments will be discussed. J. McMillan, S. Fortman, C. Neese, F. DeLucia, ApJ. 795, 56 (2014)

EFFECT OF RADIATION ON RESPONSE TO ANESTHETIC AGENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zauder, H.L.; Orkin, L.R.

1963-07-01

An attempt was made to determine if prior irradiation modified the response to anesthesia or if any anesthetic or anesthetics are associated with an abnormally high or low mortality, following irradiation. Swiss mice were irradiated by a conventional radiotherapy machine utilizing 250-kv x rays with 1- mm aluiminum and 0.5 mm copper filtration. The half-value layer was 1.5 mm of copper, and with a target-skin distance of 70 cm; the dose rate in air was 52 r/ min. A dose-response curve, relating mortality at 30 days to the amount of radiation delivered gave an LD/sub 5/ of 350 r, LD/submore » 25/ of 450 r, and LD/sub 95/ of 750 r. A chamber for the anesthetization of small animals with a known, reproducible concentration of anesthetic agent was designed providing for constant circulation of the gas mixtures, explosive or nonexplosive. Utilizing this apparatus, groups of mice were andesthetized with 6% divinyl ether, 6% diethyl ether, 1.5% halothane, 1.8% trichlorethylene, and 18% cyclopropane. With the latter, oxygen was added to the chamber in sufficient quandtity to provide a concentration of 20 to 25%. Pentobarbital (Nembutal) 30 mg/kg, thiopental sodium (Pentothal) 70 mg/kg, or meperidine hydrochloride (Demerol) 25 mg/kg was injected intraperitoneally into mice with and without prior x radiation. There was no mortality associated with these dosages in the control animals. All drugs were administered to the irradiated animals on the 1st to 28th day postirradiation. In mice irradiated with an LD/sub 5/ (350 r) and anesthetized subsequently with divinyl ether, diethyl ether, or halothane, an increase in the mortality over control values was observed. This increase was greatest following divinyl ether; its administration 7 or more days following irradiation resulted in the death of 10 to 30% of the animals during the 45-min period of anesthetization. After 350 r, meperidine and pentobarbital did not increase montality, but thiopental increased markedly the number of deaths when administered on the 2nd, 4th, or 21st day postirradiation. After 450 r the mortality rate was increased markedly, but cyclopropane was associated with the least increase. As with the volatile agents, mortality following the parenterally administered agents increased as the dose of radiation increased, but no difference wss demonstrated between pentobarbital and its thio derivative. Sleeping time following both drugs was increased 3-fold over that in controls. The mortality following anesthesia in mice who received 750-r (LD/sub 95/) made it impossible to anesthetize these animals beyond the 7th day postirradiation. Again, a significant number of deaths under anesthesia occurred with divinyl ether, and sleeping time following the barbiturates was prolonged, but not beyond the 3-fold increase which was seen at 450 r. It is concluded that divinyl ether is associated with the highest overall mortality and cyclopropane with the lowest; decreasing the concentration of diethyl ether decreases the mortality. The cause of the increased mortality is unknown, since gross and microscopic examinations of autopsy material failed to reveal any differences accounting for these results. (BBB)« less

Analysis of Environmental Chemical Mixtures and Non-Hodgkin Lymphoma Risk in the NCI-SEER NHL Study

PubMed Central

Czarnota, Jenna; Gennings, Chris; Colt, Joanne S.; De Roos, Anneclaire J.; Cerhan, James R.; Severson, Richard K.; Hartge, Patricia; Ward, Mary H.

2015-01-01

Background There are several suspected environmental risk factors for non-Hodgkin lymphoma (NHL). The associations between NHL and environmental chemical exposures have typically been evaluated for individual chemicals (i.e., one-by-one). Objectives We determined the association between a mixture of 27 correlated chemicals measured in house dust and NHL risk. Methods We conducted a population-based case–control study of NHL in four National Cancer Institute–Surveillance, Epidemiology, and End Results centers—Detroit, Michigan; Iowa; Los Angeles County, California; and Seattle, Washington—from 1998 to 2000. We used weighted quantile sum (WQS) regression to model the association of a mixture of chemicals and risk of NHL. The WQS index was a sum of weighted quartiles for 5 polychlorinated biphenyls (PCBs), 7 polycyclic aromatic hydrocarbons (PAHs), and 15 pesticides. We estimated chemical mixture weights and effects for study sites combined and for each site individually, and also for histologic subtypes of NHL. Results The WQS index was statistically significantly associated with NHL overall [odds ratio (OR) = 1.30; 95% CI: 1.08, 1.56; p = 0.006; for one quartile increase] and in the study sites of Detroit (OR = 1.71; 95% CI: 1.02, 2.92; p = 0.045), Los Angeles (OR = 1.44; 95% CI: 1.00, 2.08; p = 0.049), and Iowa (OR = 1.76; 95% CI: 1.23, 2.53; p = 0.002). The index was marginally statistically significant in Seattle (OR = 1.39; 95% CI: 0.97, 1.99; p = 0.071). The most highly weighted chemicals for predicting risk overall were PCB congener 180 and propoxur. Highly weighted chemicals varied by study site; PCBs were more highly weighted in Detroit, and pesticides were more highly weighted in Iowa. Conclusions An index of chemical mixtures was significantly associated with NHL. Our results show the importance of evaluating chemical mixtures when studying cancer risk. Citation Czarnota J, Gennings C, Colt JS, De Roos AJ, Cerhan JR, Severson RK, Hartge P, Ward MH, Wheeler DC. 2015. Analysis of environmental chemical mixtures and non-Hodgkin lymphoma risk in the NCI-SEER NHL Study. Environ Health Perspect 123:965–970; http://dx.doi.org/10.1289/ehp.1408630 PMID:25748701

Transgenerational endocrine disruption and neurotoxicity in zebrafish larvae after parental exposure to binary mixtures of decabromodiphenyl ether (BDE-209) and lead.

PubMed

Chen, Lianguo; Wang, Xianfeng; Zhang, Xiaohua; Lam, Paul K S; Guo, Yongyong; Lam, James C W; Zhou, Bingsheng

2017-11-01

Polybrominated diphenyl ethers (PBDEs) and heavy metals are two key groups of electric and electronic equipment contaminants. Despite their co-occurrence in aquatic environments, their combined effects remain largely unknown, particularly under a chronic exposure regime. In the present study, adult zebrafish (Danio rerio) were exposed to environmentally relevant concentrations of BDE-209 and lead (Pb), or their binary mixtures, for 3 months. After chronic parental exposure, increased transfer of BDE-209 and Pb to the offspring eggs was activated in the coexposure groups, with BDE-197 being the predominant PBDE congener, indicating the dynamic metabolism of BDE-209 in parental zebrafish. In the presence of Pb, culturing the eggs in clean water until 5 days post-fertilization (dpf) further accelerated the debromination of BDE-209 towards BDE-197 in the offspring, caused by the preferential removal of bromine atoms at meta positions. BDE-209 and Pb combinations induced reproductive and thyroid endocrine disruption in adults, which resulted in an imbalanced deposition of hormones in the eggs. However, compared with single chemical exposure, the larval offspring at 5 dpf from the coexposure groups had reversed the adverse influences from maternal origin. In addition, the interaction between BDE-209 and Pb led to transgenerational developmental neurotoxicity in the larval offspring, where inhibited neuronal growth and neurotransmitter signaling, disorganized muscular assembly, and impaired visual function contributed to the observed neurobehavioral deficits. Overall, depending on specific biological events, the complex interaction between BDE-209 and Pb under chronic exposure resulted in significant alterations in their environmental fate and toxicological actions, thus complicating the accurate evaluation of ecological risks and constituting an unquantified threat to environmental safety. Copyright © 2017 Elsevier Ltd. All rights reserved.

Theory and tests of two-phase turbines

NASA Technical Reports Server (NTRS)

Elliott, D. G.

1982-01-01

A theoretical model for two-phase turbines was developed. Apparatus was constructed for testing one- and two-stage turbines (using speed decrease from stage to stage). Turbines were tested with water and nitrogen mixtures and refrigerant 22. Nozzle efficiencies were 0.78 (measured) and 0.72 (theoretical) for water and nitrogen mixtures at a water/nitrogen mixture ratio of 68, by mass; and 0.89 (measured) and 0.84 (theoretical) for refrigerant 22 expanding from 0.02 quality to 0.28 quality. Blade efficiencies (shaft power before windage and bearing loss divided by nozzle jet power) were 0.63 (measured) and 0.71 (theoretical) for water and nitrogen mixtures and 0.62 (measured) and 0.63 (theoretical) for refrigerant 22 with a single stage turbine, and 0,70 (measured) and 0.85 (theoretical) for water and nitrogen mixtures with a two-stage turbine.

The Biological Control of Alligatorweed

DTIC Science & Technology

1975-03-01

andersoni, a new genus and species Injurious to alUgatorweed. Proc. Entomol. Soc. Wash. 70: 175-83. Pastrana, J. A. 1961. Una nueva Phycitidae...Lep.J paraslto de la lagunllla. Tech. Pub. 71, Secretaria de Estado de Agriculturay Ganaderia de la Nation, Instituto Naclonal de Tecnologia

Sulfonimide-containing poly(arylene ether)s and poly(arylene ether sulfone)s, methods for producing the same, and uses thereof

DOEpatents

Hofmann, Michael A.

2006-11-14

The present invention is directed to sulfonimide-containing polymers, specifically sulfonimide-containing poly(arylene ether)s and sulfonimide-containing poly(arylene ether sulfone)s, and processes for making the sulfonimide-containing poly(arylene ether)s and sulfonimide-containing poly(arylene ether sulfone)s, for use conductive membranes and fuel cells.

Detection of protozoa in water samples by formalin/ether concentration method.

PubMed

Lora-Suarez, Fabiana; Rivera, Raul; Triviño-Valencia, Jessica; Gomez-Marin, Jorge E

2016-09-01

Methods to detect protozoa in water samples are expensive and laborious. We evaluated the formalin/ether concentration method to detect Giardia sp., Cryptosporidium sp. and Toxoplasma in water. In order to test the properties of the method, we spiked water samples with different amounts of each protozoa (0, 10 and 50 cysts or oocysts) in a volume of 10 L of water. Immunofluorescence assay was used for detection of Giardia and Cryptosporidium. Toxoplasma oocysts were identified by morphology. The mean percent of recovery in 10 repetitions of the entire method, in 10 samples spiked with ten parasites and read by three different observers, were for Cryptosporidium 71.3 ± 12, for Giardia 63 ± 10 and for Toxoplasma 91.6 ± 9 and the relative standard deviation of the method was of 17.5, 17.2 and 9.8, respectively. Intraobserver variation as measured by intraclass correlation coefficient, was fair for Toxoplasma, moderate for Cryptosporidium and almost perfect for Giardia. The method was then applied in 77 samples of raw and drinkable water in three different plant of water treatment. Cryptosporidium was found in 28 of 77 samples (36%) and Giardia in 31 of 77 samples (40%). Theses results identified significant differences in treatment process to reduce the presence of Giardia and Cryptosporidium. In conclusion, the formalin ether method to concentrate protozoa in water is a new alternative for low resources countries, where is urgently need to monitor and follow the presence of theses protozoa in drinkable water. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mode of Action Studies on a Chiral Diphenyl Ether Peroxidizing Herbicide

PubMed Central

Hallahan, Beverly J.; Camilleri, Patrick; Smith, Alison; Bowyer, John R.

1992-01-01

The nitrodiphenyl ether herbicide 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitroacetophenone oxime-O-(acetic acid, methyl ester) (DPEI) induced an abnormal accumulation of protoporphyrin IX in darkness in the green alga Chlamydomonas reinhardtii, as determined by high-performance liquid chromatography and spectrofluorimetry. It also inhibited the increase in cell density of the alga in light-grown cultures with an I50 (concentration required to decrease cell density increase to 50% of the noninhibited control value) of 0.16 μm. The relative ability of four peroxidizing diphenyl ether herbicides to cause tetrapyrrole accumulation in C. reinhardtii correlated qualitatively with their ability to inhibit the increase in cell density in light-grown cultures. The purified S(−) enantiomer of the optically active phthalide DPE 5-[2-chloro-4-(trifluoromethyl)phenoxy]-3-methylphthalide (DPEIII), which has greater herbicidal activity than the R(+) isomer, induces a 4- to 5-fold greater tetrapyrrole accumulation than the R(+) isomer. The I50 for inhibition of increase in cell density in light-grown cultures of C. reinhardtii by the S(−) isomer (0.019 μm) is less than 25% of that for the R(+) isomer. DPEIII inhibits protoporphyrinogen IX oxidase activity in pea (Pisum sativum) etioplast lysates, with the S(−) enantiomer showing considerably greater potency than the R(+) isomer and the racemic mixture showing a potency intermediate between the two. The results indicate that the site at which DPEs inhibit protoporphyrinogen IX oxidase shows chiral discrimination and provide further evidence for the link between inhibition of this enzyme, protoporphyrin IX accumulation, and the phytotoxicity of DPE herbicides. PMID:16653107

BDE-99, but not BDE-47, is a transient aryl hydrocarbon receptor agonist in zebrafish liver cells.

PubMed

Yang, Jie; Zhu, Jinyong; Chan, King Ming

2016-08-15

Polybrominated diphenyl ethers (PBDEs) are endocrine-disrupting chemicals that affect the environment and the health of humans and wildlife. In this study, the zebrafish liver (ZFL) cell line was used in vitro to investigate two major PBDE contaminants: 2, 2', 4, 4', 5-pentabromodiphenyl ether (BDE-99) and 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47). BDE-99 was found to significantly induce cytochrome P450 (CYP1A), uridine diphosphate glucuronosyl transferase 1 family a, b (ugt1ab), 7-ethoxyresorufin-O-deethylase activity and an aryl hydrocarbon receptor (Ahr) dependent xenobiotic response element luciferase reporter system, confirming the Ahr-mediated activation of CYP1A by BDE-99. The time-course effect indicated that the role of BDE-99 in Ahr-mediated signaling is likely to be transient and highly dependent on the ability of BDE-99 to induce CYP1A and ugt1ab, and presumably its metabolism. BDE-99 also exhibited a significant dose-response effect on a developed zebrafish pregnane X receptor luciferase reporter gene system. However, the other abundant contaminant under study, BDE-47, did not exhibit the above effects. Together, these results indicated that the molecular mechanism of PBDEs induced in ZFL cells is a chemically specific process that differs between members of the PBDE family. CYP1A induction derived by BDE-99 warrants further risk assessment as the humans, wildlife and environment are exposed to a complex mixture including dioxin-like compounds and carcinogenic compounds. Copyright © 2016 Elsevier Inc. All rights reserved.

Velocidades radiales Coravel y fotometría UBV de gigantes rojas del cúmulo abierto Melotte71

NASA Astrophysics Data System (ADS)

Mermilliod, J. C.; Clariá, J. J.; Andersen, J.; Mayor, M.

Se presentan velocidades radiales determinadas con el espectrovelocímetro CORAVEL y fotometría UBV de 24 gigantes rojas del cúmulo abierto de edad-intermedia Melotte71. Las observaciones realizadas en La Silla y Cerro Tololo permiten confirmar la pertenencia al cúmulo de 16 estrellas, de las cuales 8 constituyen nuevas binarias espectroscópicas cuyos períodos oscilan entre 74 y 1627 días. La velocidad radial media es +57.17 ± 0.47 km/s. El mejor ajuste con una isócrona teórica se obtiene para log t (edad) = 9.00 y Z = 0.008, no obstante existir algunas discrepancias respecto de la ubicación predicha y observada del ``clump".

Optimal production of L-threo-2,3-dihydroxyphenylserine (L-threo-DOPS) on a large scale by diastereoselectivity-enhanced variant of L-threonine aldolase expressed in Escherichia coli.

PubMed

Gwon, Hui-Jeong; Yoshioka, Hideki; Song, Nho-Eul; Kim, Jong-Hui; Song, Young-Ran; Jeong, Do-Youn; Baik, Sang-Ho

2012-01-01

This study examined the efficient production and optimal separation procedures for pure L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) from a mixture of diastereomers synthesized by whole-cell aldol condensation reaction, harboring diastereoselectivity-enhanced L-threonine aldolase in Escherichia coli JM109. The addition of the reducing agent sodium sulfite was found to stimulate the production of L-threo-DOPS without affecting the diastereoselectivity ratio, especially at the 50 mM concentration. The optimal pH for diastereoselective synthesis was 6.5. The addition of Triton X-100 also strongly affected the synthesis yield, showing the highest conversion yield at a 0.75% concentration; however, the diastereoselectivity of the L-threonine aldolase was not affected. Lowering the temperature to 10°C did not significantly affect the diastereoselectiviy without affecting the synthesis rate. At the optimized conditions, a mixture of L-threo-DOPS and L-erythro-DOPS was synthesized by diastereoselectivity-enhanced L-threonine aldolase from E. coli in a continuous process for 100 hr, yielding an average of 4.0 mg/mL of L-threo-DOPS and 60% diastereoselectivity (de), and was subjected to two steps of ion exchange chromatography. The optimum separation conditions for the resin and solvent were evaluated in which it was found that a two-step process with the ion-exchange resin Dowex 50 W × 8 and activated carbon by washing with 0.5 N acetic acid was sufficient to separate the L-threo-DOPS. By using two-step ion-exchange chromatography, synthesized high-purity L-threo-DOPS of up to 100% was purified with a yield of 71%. The remaining substrates, glycine and 3,4-dihydroxybenzaldehyde, were recovered successfully with a yield of 71.2%. Our results indicate this potential procedure as an economical purification process for the synthesis and purification of important L-threo-DOPS at the pharmaceutical level.

Cytoplasmic Delivery of Liposomal Contents Mediated by an Acid-Labile Cholesterol-Vinyl Ether-PEG Conjugate

PubMed Central

Boomer, Jeremy A.; Qualls, Marquita M.; Inerowicz, H. Dorota; Haynes, Robert H.; Patri, G.V. Srilaksmi; Kim, Jong-Mok; Thompson, David H.

2009-01-01

An acid-cleavable PEG lipid, 1′-(4′-cholesteryloxy-3′-butenyl)-ω-methoxy-polyethylene[112] glycolate (CVEP), has been developed that produces stable liposomes when dispersed as a minor component (0.5–5 mol%) in 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). Cleavage of CVEP at mildly acidic pH’s results in dePEGylation of the latently fusogenic DOPE liposomes, thereby triggering the onset of contents release. This paper describes the synthesis of CVEP via a six step sequence starting from the readily available precursors 1,4-butanediol, cholesterol, and mPEG acid. The hydrolysis rates and release kinetics from CVEP:DOPE liposome dispersions as a function of CVEP loading, as well as the cryogenic transmission electron microscopy and pH-dependent monolayer properties of 9:91 CVEP:DOPE mixtures, also are reported. When folate-receptor positive KB cells were exposed to calcein-loaded 5:95 CVEP:DOPE liposomes containing 0.1 mol% folate-modified 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-polyethylene[76] glycolamide (folate-PEG-DSPE), efficient delivery of the calcein cargo to the cytoplasm of the cells was observed as determined by fluorescence microscopy and flow cytometry. Fluorescence resonance energy transfer analysis of lipid mixing in these cells was consistent with membrane-membrane fusion between the liposome and endosomal membranes. PMID:19072698

Stabilized three-stage oxidation of DME/air mixture in a micro flow reactor with a controlled temperature profile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oshibe, Hiroshi; Nakamura, Hisashi; Tezuka, Takuya

Ignition and combustion characteristics of a stoichiometric dimethyl ether (DME)/air mixture in a micro flow reactor with a controlled temperature profile which was smoothly ramped from room temperature to ignition temperature were investigated. Special attention was paid to the multi-stage oxidation in low temperature condition. Normal stable flames in a mixture flow in the high velocity region, and non-stationary pulsating flames and/or repetitive extinction and ignition (FREI) in the medium velocity region were experimentally confirmed as expected from our previous study on a methane/air mixture. In addition, stable double weak flames were observed in the low velocity region for themore » present DME/air mixture case. It is the first observation of stable double flames by the present methodology. Gas sampling was conducted to obtain major species distributions in the flow reactor. The results indicated that existence of low-temperature oxidation was conjectured by the production of CH{sub 2}O occured in the upstream side of the experimental first luminous flame, while no chemiluminescence from it was seen. One-dimensional computation with detailed chemistry and transport was conducted. At low mixture velocities, three-stage oxidation was confirmed from profiles of the heat release rate and major chemical species, which was broadly in agreement with the experimental results. Since the present micro flow reactor with a controlled temperature profile successfully presented the multi-stage oxidations as spatially separated flames, it is shown that this flow reactor can be utilized as a methodology to separate sets of reactions, even for other practical fuels, at different temperature. (author)« less

[Effect of the harvest season on the composition of raw and fermented cotyledons of 2 varieties of cacao and shell fractions].

PubMed

de Dios Alvarado, J; Villacís, F E; Zamora, G F

1983-06-01

A study was carried out wherein during the period August 1979 to January 1980, samples of raw and fermented cacao were analyzed monthly. These included two varieties: Arriba, taken from a farm in "Quevedo", and the EET-19, grown in "Pichilingüe" by the Instituto Nacional de Investigaciones Agropecuarias (INIAP). Taking the ear of cacao as a basis, the weight of its main parts was determined. The proximal composition was established in the cotyledons, with significant statistical differences in regard to moisture, protein, and ether extract content according to the month of harvest. As to the fermentation process, differences in moisture, ether extract and ash content were detected; differences in the ether extract and ash content were found between the two varieties. The fat extracted from the cotyledons presented different iodine, saponification and acidity index values between the raw and fermented samples, but none were determined between the varieties; as far as the month of harvest is concerned, differences in the acidity index were observed. The percentage composition of the main fatty acids is reported (palmitic, stearic, oleic, and linoleic acids). In order to suggest possible industrial ways of utilizing the cacao shell by-product which is discarded by the shelling machine, the chemical characteristics of five fractions were determined based on the functioning of the shelling machine. The moisture, protein, ether extract, ash, crude fiber, theobromine, and caffeine contents varied among the fractions, and it was dependent on the broken "nibs" content. Differences in the protein, ether extract, and ash content, according to the months of production, were found. Obviously, the high fat content in fractions A (fine dust) and B (fine ground), which varied from 30 to 11 g/100 g, merits its extraction; the remainder meal has a valuable protein and alkaloid content. The chemical characteristics of the fat extracted from the shell of two fractions were similar to the fat extracted from the cotyledons.

Sensor arrays for detecting analytes in fluids

NASA Technical Reports Server (NTRS)

Freund, Michael S. (Inventor); Lewis, Nathan S. (Inventor)

2000-01-01

A sensor array for detecting an analyte in a fluid, comprising at least first and second chemically sensitive resistors electrically connected to an electrical measuring apparatus, wherein each of the chemically sensitive resistors comprises a mixture of nonconductive material and a conductive material. Each resistor provides an electrical path through the mixture of nonconductive material and the conductive material. The resistors also provide a difference in resistance between the conductive elements when contacted with a fluid comprising an analyte at a first concentration, than when contacted with an analyte at a second different concentration. A broad range of analytes can be detected using the sensors of the present invention. Examples of such analytes include, but are not limited to, alkanes, alkenes, alkynes, dienes, alicyclic hydrocarbons, arenes, alcohols, ethers, ketones, aldehydes, carbonyls, carbanions, polynuclear aromatics, organic derivatives, biomolecules, sugars, isoprenes, isoprenoids and fatty acids. Moreover, applications for the sensors of the present invention include, but are not limited to, environmental toxicology, remediation, biomedicine, material quality control, food monitoring and agricultural monitoring.

PREPARATION OF DIBASIC ALUMINUM NITRATE

DOEpatents

Gresky, A.T.; Nurmi, E.O.; Foster, D.L.; Wischow, R.P.; Savolainen, J.E.

1960-04-01

A method is given for the preparation and recovery of basic aluminum nltrates having an OH: Al ratio of at least two, comprising two steps. First, metallic aluminum is dissolved in aqueous Al(NO/sub 3/)/sub 3/, in the presence of a small quantity of elemental or ionic mercury, to increase its Al: NO/sub 3/ ratio into the range 1 to 1.2. The resulting aqueous solution is then added to an excess of a special organic solvent, typically a mixture of five parts methanol and six parts diethyl ether, whereupon the basic aluminum nitrate, e.g. Al/sub 6/(OH)/sub 13/-(NO/sub 3/)/sub 5/, recoverably precipitates.

Glycerol triacetate as solvent and acyl donor in the production of isoamyl acetate with Candida antarctica lipase B.

PubMed

Wolfson, Adi; Atyya, Aviad; Dlugy, Christina; Tavor, Dorith

2010-03-01

Glycerol triacetate was successfully used as a green solvent and as the acyl donor in the transesterification of isoamyl alcohol to produce isoamyl acetate using free and immobilized Candida antarctica lipase B. Immobilized lipase was more catalytically active than free lipase and could be easily separated from the reaction mixture by filtration. In addition, it was found that increasing either the reaction temperature or the enzyme to substrate ratio increased the conversion of isoamyl alcohol. Using triacetin as the solvent also enabled the separation of product by simple extraction with petroleum ether and catalyst recycling.

Prayon process for wet acid purification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davister, A.; Peeterbroeck, M.

Described is a process developed in Belgium which enables the upgrading technical phosphoric acid to feed and food grades. After laboratory and pilot tests, Prayon developed and patented a solvent extraction process using a mixture of di-isopropyl ether and tributyl phosphate as solvent. The purified phosphoric acid obtained complies with the quality requirements of the market and can be used for metal treatments, in the manufacture of pure phosphates, for cattle feed, by the fermentation industry, for beverages, etc. Among the advantages of this process are its simplicity of operation, its low power consumption, and minimal environmental pollution. Extensive technologicalmore » data are given.« less

One-step liquid-liquid extraction of cocaine from urine samples for gas chromatographic analysis.

PubMed

Farina, Marcelo; Yonamine, Maurício; Silva, Ovandir A

2002-07-17

An improved technique for cocaine extraction from urine samples for gas chromatographic (GC) analysis is described. Employing a simple liquid-liquid extraction (LLE) of cocaine with a mixture of ethyl ether:isopropanol (9:1) the method presents a mean recovery of 74.49%. Limit of detection (LOD) and limit of quantification (LOQ) were 5 and 20 ng/ml, respectively. The method is highly precise (coefficient of variation (CV) <8%) and linear from 20 to 2000 ng/ml. It can he applied to detect the presence of cocaine in urine as a marker of its recent use in drug abuse treatment protocols.

The extraction and chromatographic determination of the essentials oils from Ocimum basilicum L. by different techniques

NASA Astrophysics Data System (ADS)

Loredana Soran, Maria; Codruta Cobzac, Simona; Varodi, Codruta; Lung, Ildiko; Surducan, Emanoil; Surducan, Vasile

2009-08-01

Three different techniques (maceration, sonication and extraction in microwave field) were used for extraction of essential oils from Ocimum basilicum L. The extracts were analyzed by TLC/HPTLC technique and the fingerprint informations were obtained. The GC-FID was used to characterized the extraction efficiency and for identify the terpenic bioactive compounds. The most efficient extraction technique was maceration followed by microwave and ultrasound. The best extraction solvent system was ethyl ether + ethanol (1:1, v/v). The main compounds identified in Ocimum basilicum L. extracts were: α and β-pinene (mixture), limonene, citronellol, and geraniol.

Synthesis and Useful Reactions of Organosilicon Polymeric Precursors for Ceramics

DTIC Science & Technology

1992-04-05

composites are hot pressing, chemical vapor infiltration , reaction bonding and polymer infiltration / pyrolysis . Thus the inorganic or organometallic...to prepare preceramic polymers whose D; pyrolysis gives -99% SiC , -99.5% Si 3 N4 , or any mixture of the two by appropriate manipulation of the...the standard furnace pyrolysis of the polymer gave a ceramic of composition 96.6% SiC , 1.7% ZrC and 1.7% Si in 71% yield. Finally, (71-C

Oriented thin films of mixture of a low-bandgap polymer and a fullerene derivative prepared by friction-transfer method

NASA Astrophysics Data System (ADS)

Tanigaki, Nobutaka; Mizokuro, Toshiko; Miyadera, Tetsuhiko; Shibata, Yousei; Koganezawa, Tomoyuki

2018-02-01

We have been studying oriented thin films of polymers fabricated by the friction-transfer method, which allows the alignment of a variety of conjugated polymers into highly oriented films. In this study, we prepared oriented blend films of a mixture of a low-bandgap polymer, poly{4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b‧]dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophene-4,6-diyl} (PTB7), and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM), which is a promising combination for application in organic solar cells. We obtained oriented blend films of PTB7 and PC71BM by the friction-transfer method from a solid block. Polarized UV-visible spectra show that the PTB7 chains were aligned parallel to the friction direction in the blend films. Grazing-incidence X-ray diffraction (GIXD) studies with synchrotron radiation suggested that the preferred orientation of PTB7 crystallites was face-on in the blend films. The GIXD results also showed the high uniaxial orientation of PTB7 chains in blend films. Photovoltaic devices were fabricated using the friction-transferred blend films of the PTB7 and PC71BM. These bulk heterojunction devices showed better performance than planar heterojunction devices fabricated using pure friction-transferred PTB7 films.

Synthesis and biological studies of positron-emitting radiopharmaceuticals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dischino, D.D.

The development and clinical evaluation of two-positron emitting radiopharmaceuticals designed to image myelin in humans is reported. Carbon-11-labeled benzyl methyl ether was synthesized by the reaction of carbon-11-labeled methanol and benzyl chloride in dimethyl sulfoxide containing powdered potassium hydroxide in a radiochemical yield of 43% and a synthesis and purification time of 40 minutes. Carbon-11-labeled diphenylmethanol was synthesized by the reaction of carbon-11-labeled carbon dioxide and phenyllithium followed by the reduction of the carbon-11-labeled intermediate to diphenylmethanol via lithium aluminum hydride in a radiochemical yield of 71% and a synthesis and purification time of 38 minutes. Carbon-11-labeled benzyl methyl ethermore » and diphenylmethanol were each evaluated as myelin imaging agents in three patients with multiple sclerosis via positron-emission tomography. In two out of three patients studied with carbon-11-labeled benzyl methyl ether, the distribution of activity in the brain was not consistent with local lipid content. A new synthesis of carbon-11-labeled-DL-phenylalanine labeled in the benzylic position and the synthesis of fluorine-18-labeled 1-(2-nitro-1-imidazolyl)-3-fluoro-2-propanol, a potential in vivo marker of hypoxic tissue, are reported.« less

Positively charged and bipolar layered poly(ether imide) nanofiltration membranes for water softening applications

NASA Astrophysics Data System (ADS)

Gassara, S.; Abdelkafi, A.; Quémener, D.; Amar, R. Ben; Deratani, A.

2015-07-01

Poly(ether imide) (PEI) ultrafiltration membranes were chemically modified with branched poly(ethyleneimine) to obtain nanofiltration (NF) membrane Cat PEI with a positive charge in the pH range below 9. An oppositely charged polyelectrolyte layer was deposited on the resulting membrane surface by using sodium polystyrene sulfonate (PSSNa) and sodium polyvinyl sulfonate (PVSNa) to prepare a bipolar layered membrane NF Cat PEI_PSS and Cat PEI_PVS having a negatively charged surface and positively charged pores. Cat PEI exhibited good performance to remove multivalent cations (more than 90% of Ca2+) from single salt solutions except in presence of sulfate ions. Adding an anionic polyelectrolyte layer onto the positively charged surface resulted in a significant enhancement of rejection performance even in presence of sulfate anions. Application of the prepared membranes in water softening of natural complex mixtures was successful for the different studied membranes and a large decrease of hardness was obtained. Moreover, Cat PEI_PSS showed a good selectivity for nitrate removal. Fouling experiments were carried out with bovine serum albumin, as model protein foulant. Cat PEI_PSS showed much better fouling resistance than Cat PEI with a quantitative flux recovery ratio.

Kinetic modelling of the oxidation of large aliphatic hydrocarbons using an automatic mechanism generation.

PubMed

Muharam, Yuswan; Warnatz, Jürgen

2007-08-21

A mechanism generator code to automatically generate mechanisms for the oxidation of large hydrocarbons has been successfully modified and considerably expanded in this work. The modification was through (1) improvement of the existing rules such as cyclic-ether reactions and aldehyde reactions, (2) inclusion of some additional rules to the code, such as ketone reactions, hydroperoxy cyclic-ether formations and additional reactions of alkenes, (3) inclusion of small oxygenates, produced by the code but not included in the handwritten C(1)-C(4) sub-mechanism yet, to the handwritten C(1)-C(4) sub-mechanism. In order to evaluate mechanisms generated by the code, simulations of observed results in different experimental environments have been carried out. Experimentally derived and numerically predicted ignition delays of n-heptane-air and n-decane-air mixtures in high-pressure shock tubes in a wide range of temperatures, pressures and equivalence ratios agree very well. Concentration profiles of the main products and intermediates of n-heptane and n-decane oxidation in jet-stirred reactors at a wide range of temperatures and equivalence ratios are generally well reproduced. In addition, the ignition delay times of different normal alkanes was numerically studied.

Analysis of fingerprints features of infrared spectra of various processed products of Radix Aconiti kusnezoffii

NASA Astrophysics Data System (ADS)

Tu-ya; Yang, Ping; Sun, Su-qin; Zhou, Qun; Bao, Xiao-hua; Noda, Isao

2010-06-01

Fourier-transform infrared spectroscopy (FTIR) and two-dimensional correlation infrared spectroscopy (2D-IR)) are employed to analyze various processed products and ether extracts of Radix Aconiti kusnezoffii. There is a resemblance among the spectra of different processed products. The major difference lies in the absorption peak at 1641 cm -1 in the IR spectra, which reflects the transformation of raw aconite to the processed products. There are distinctive differences in the absorption peaks in the range of 1800-1500 cm -1 in the second derivative spectra, which has better resolution, of different processed products. 2D-IR spectra, which elevate the resolution further, can present even more differences among the products in the range of 1800-800 cm -1. Analysis of ether extracts of various processed products proves that there are alcohols, esters, carboxylic acids or ketones in all of them. However, their contents in different samples have obvious differences. With the advantages of high resolution, high-speed and convenience, IR can quickly and precisely distinguish various processed products of Radix A. kusnezoffii, and can be applied to predict the tendency of transformation of the complicated chemical mixture systems under heat perturbation.

Polybrominated diphenyl ether flame retardants in Virginia freshwater fishes (USA).

PubMed

Hale, R C; La Guardia, M J; Harvey, E P; Mainor, T M; Duff, W H; Gaylor, M O

2001-12-01

Polybrominated diphenyl ethers (PBDEs) were examined in fish fillets collected from two large Virginia watersheds. Emphasis was on the tetra- to hexabrominated congeners since these exhibit the greatest bioaccumulation and toxicological potentials. These congeners are dominant constituents of Penta-, a commercial PBDE product used to flame retard polyurethane foam. In 1999, North America accounted for98% of global Penta-demand. Concentrations of total tetra- to hexabrominated congeners in fillets ranged from <5 to 47,900 microg/kg (lipid basis). BDE-47, one of the two major constituents of Penta-, was detected in 89% of samples and contributed 40-70% of the total PBDEs observed. Concentrations of BDE-99, the second major constituent of the Penta- commercial mixture, were much lower in fish. While some differences in PBDE profiles between fish species were apparent, dominant congeners were consistent with those in surficial sediments from the Virginia sites and recently published data for U.S. air samples. PCB and PBDE concentrations in fish were generally associated. These factors point to exposure from nonpoint sources. Exceptions existed, likely due to inputs from local sources. The Virginia study area has historically served as a center for furniture and textile manufacturing, although polyurethane foam production here has been limited.

William Russ Pugh's remarkable life: natural scientist, innovative anaesthetist and founding member of the Royal Society of Tasmania.

PubMed

Paull, J D

2011-07-01

While well known in anaesthetic circles for being the first to provide ether anaesthesia for a surgical procedure in June 1847 in Launceston, Tasmania, William Russ Pugh's achievements in the field of natural history are less well known. He personally assisted Count Peter de Strzelecki in the chemical analysis of Australian coal and mineral samples and provided the laboratory space and equipment. His analytic skills were utilised by coroners in cases of poisoning. He was consulted about a ship's cargo which threatened to spontaneously combust in Launceston's port. He was a founding member of the Tasmanian Society and subsequently of the Royal Society of Tasmania. He made many presentations on geology, zoology, botany, mineralogy and meteorology to meetings of both Societies. These scientific interests may have provided the knowledge and motivation which encouraged Pugh to proceed so confidently with the introduction of ether anaesthesia.

Coordination chemistry in magnesium battery electrolytes: how ligands affect their performance.

PubMed

Shao, Yuyan; Liu, Tianbiao; Li, Guosheng; Gu, Meng; Nie, Zimin; Engelhard, Mark; Xiao, Jie; Lv, Dongping; Wang, Chongmin; Zhang, Ji-Guang; Liu, Jun

2013-11-04

Magnesium battery is potentially a safe, cost-effective, and high energy density technology for large scale energy storage. However, the development of magnesium battery has been hindered by the limited performance and the lack of fundamental understandings of electrolytes. Here, we present a study in understanding coordination chemistry of Mg(BH₄)₂ in ethereal solvents. The O donor denticity, i.e. ligand strength of the ethereal solvents which act as ligands to form solvated Mg complexes, plays a significant role in enhancing coulombic efficiency of the corresponding solvated Mg complex electrolytes. A new electrolyte is developed based on Mg(BH₄)₂, diglyme and LiBH₄. The preliminary electrochemical test results show that the new electrolyte demonstrates a close to 100% coulombic efficiency, no dendrite formation, and stable cycling performance for Mg plating/stripping and Mg insertion/de-insertion in a model cathode material Mo₆S₈ Chevrel phase.

Exposure to a PBDE/OH-BDE mixture alters juvenile zebrafish (Danio rerio) development

PubMed Central

Macaulay, Laura J.; Chernick, Melissa; Chen, Albert; Hinton, David E.; Bailey, Jordan M.; Kullman, Seth W.; Levin, Edward D.; Stapleton, Heather M.

2017-01-01

Polybrominated diphenyl ethers (PBDEs) and halogenated phenolic compounds (e.g., hydroxylated BDEs (OH-BDEs)) arecontaminants detected together frequently in human tissues, and are structurally similar to thyroid hormones (TH). THs partially mediate metamorphic transitions between life stages in zebrafish, making this a critical developmental window which may be uniquely vulnerable to chemicals disrupting thyroid signaling. In this study, zebrafish were exposed to 6-OH-BDE-47 (30 nM) alone or to a low (30 μg/L) or high dose (600 μg/L) mixture of PentaBDEs, 6-OH-BDE-47 (0.5–6 μg/L), & 2,4,6 tribromophenol (TBP) (5–100 μg/L) during juvenile development (9–23 days post fertilization; dpf) and evaluated for developmental endpoints mediated by TH signaling. Fish were sampled at three time points and examined for developmental and skeletal morphology, apical thyroid and skeletal gene markers, and modifications in swimming behavior (as adults). Exposure to the high mixture resulted in > 85% mortality within one week of exposure, despite being below reported acute toxicity thresholds for individual congeners. The low mixture and 6-OH-BDE-47 groups exhibited reductions in body length and delayed maturation, specifically relating to swim bladder,?, fin, and pigmentation development. Reduced skeletal ossification was also observed in 6-OH-BDE-47 treated fish. Assessment of thyroid and osteochondral gene regulatory networks demonstrated significantly increased expression of genes that regulate skeletal development and THs. Overall, these results indicate that exposures to PBDEs/OH-BDEs mixtures adversely impact zebrafish maturation during metamorphosis. PMID:27329031

Critical Casimir forces, Goldstone modes and anomalous wetting

NASA Astrophysics Data System (ADS)

Balibar, Sebastien

2004-03-01

We have measured the contact angle of a ^3He - ^4He interface on a sapphire window, near the tricritical temperature Tt of liquid helium mixtures (T. Ueno et al., J. Low Temp. Phys. 130, 543, 2003). We have found the first experimental evidence of a violation of "critical point wetting", the general phenomenon introduced by J.W. Cahn in 1977. We then proposed that Fisher and de Gennes' "critical Casimir effect" provides the necessary long range force for this anomalous wetting behavior to occur (T. Ueno et al. Phys. Rev. Lett. 90, 116102, 2003). Our measurements are now extended to the superfluid region far below the tricritical temperature T_t. Our goal is to test the prediction by M. Kardar and R. Golestanian that the confinement of Goldstone modes in superfluid films leads to an additionnal contribution to the Casimir force (M. Kardar and R. Golestanian, Rev. Mod. Phys. 71, 1233, 1999). We compare theoretical predictions to experimental results.

Poly(arylene ether)s containing pendent ethynyl groups

NASA Technical Reports Server (NTRS)

Hergenrother, Paul M. (Inventor); Jensen, Brian J. (Inventor)

1996-01-01

Poly(arylene ether)s containing pendent ethynyl and substituted ethynyl groups and poly(arylene ether) copolymers containing pendent ethynyl and substituted ethynyl groups are readily prepared from bisphenols containing ethynyl and substituted ethynyl groups. The resulting polymers are cured up to 350.degree. C. to provide crosslinked poly(arylene ether)s with good solvent resistance, high strength and modulus.

Poly(arylene ether)s containing pendent ethynyl groups

NASA Technical Reports Server (NTRS)

Hergenrother, Paul M. (Inventor); Jensen, Brian J. (Inventor)

1994-01-01

Poly(arylene ether)s containing pendent ethynyl and substituted ethynyl groups and poly(arylene ether) copolymers containing pendent ethynyl and substituted ethynyl groups are readily prepared from bisphenols containing ethynyl and substituted ethynyl groups. The resulting polymers are cured up to 350 C to provide crosslinked poly(arylene ether)s with good solvent resistance, high strength and modulus.

Radiolabeled cholesteryl ethers: A need to analyze for biological stability before use.

PubMed

Manual Kollareth, Denny Joseph; Chang, Chuchun L; Hansen, Inge H; Deckelbaum, Richard J

2018-03-01

Radiolabeled cholesteryl ethers are widely used as non-metabolizable tracers for lipoproteins and lipid emulsions in a variety of in vitro and in vivo experiments. Since cholesteryl ethers do not leave cells after uptake and are not hydrolyzed by mammalian cellular enzymes, these compounds can act as markers for cumulative cell uptakes of labeled particles. We have employed [ 3 H]cholesteryl oleoyl ether to study the uptake and distribution of triglyceride-rich emulsion particles on animal models. However, questionable unexpected results compelled us to analyze the stability of these ethers. We tested the stability of two commercially available radiolabeled cholesteryl ethers - [ 3 H]cholesteryl oleoyl ether and [ 3 H]cholesteryl hexadecyl ether from different suppliers, employing in vitro , in vivo and chemical model systems. Our results show that, among the two cholesteryl ethers tested, one ether was hydrolyzed to free cholesterol in vitro , in vivo and chemically under alkaline hydrolyzing agent. Free cholesterol, unlike cholesteryl ether, can then re-enter the circulation leading to confounding results. The other ether was not hydrolyzed to free cholesterol and remained as a stable ether. Hence, radiolabeled cholesteryl ethers should be analyzed for biological stability before utilizing them for in vitro or in vivo experiments.

Purification of optical imaging ligand-Cybesin by high-speed counter-current chromatography

PubMed Central

Ma, Zhiyong; Ma, Ying; Sun, Xilin; Ye, Yunpeng; Shen, Baozhong; Chen, Xiaoyuan; Ito, Yoichiro

2010-01-01

Fluorescent Cybesin (Cypate-Bombesin Peptide Analogue Conjugate) was synthesized from Indocyanine Green (ICG) and the bombesin receptor ligand as a contrast agent for detecting pancreas tumors. However, the LC–MS analysis indicated that the target compound was only a minor component in the reaction mixture. Since preparative HPLC can hardly separate such a small amount of the target compound directly from the original crude reaction mixture without a considerable adsorptive loss onto the solid support, high-speed counter-current chromatography (HSCCC) was used for purification since the method uses no solid support and promises high sample recovery. A suitable two-phase solvent system composed of hexane/ethyl acetate/methanol/methyl t.-butyl ether/acetonitrile/water) at a volume ratio of 1:1:1:4:4:7 was selected based on the partition coefficient of Cybesin (K ≈ 0.9) determined by LC–MS. The separation was performed in two steps using the same solvent system with lower aqueous mobile phase. From 400 mg of the crude reaction mixture the first separation yielded 7.7 mg of fractions containing the target compound at 12.8% purity, and in the second run 1 mg of Cybesin was obtained at purity of 94.0% with a sample recovery rate of over 95% based on the LC–MS Analysis. PMID:20933483

Polybrominated diphenyl ethers (PBDEs) and heavy metals in road dusts from a plastic waste recycling area in north China: implications for human health.

PubMed

Tang, Zhenwu; Huang, Qifei; Yang, Yufei; Nie, Zhiqiang; Cheng, Jiali; Yang, Jun; Wang, Yuwen; Chai, Miao

2016-01-01

Road dusts were collected from an area where intense mechanical recycling of plastic wastes occurs in Wen'an, north China. These dusts were investigated for polybrominated diphenyl ethers (PBDEs) and heavy metals contamination to assess the health risk related to these components. Decabromodiphenyl ether (BDE-209) and Σ21PBDE concentrations in these dusts ranged from 2.67 to 10,424 ng g(-1) and from 3.23 to 10,640 ng g(-1), respectively. These PBDE concentrations were comparable to those observed in road dust from e-waste recycling areas but were 1-2 orders of magnitude higher than concentrations in outdoor or road dusts from other areas. This indicates that road dusts in the study area have high levels of PBDE pollution. BDE-209 was the predominant congener, accounting for 86.3% of the total PBDE content in dusts. Thus, commercial deca-BDE products were the dominant source. The average concentrations of As, Cd, Cr, Cu, Hg, Pb, Sb, and Zn in these same dust samples were 10.1, 0.495, 112, 54.7, 0.150, 71.8, 10.6, and 186 mg kg(-1), respectively. The geoaccumulation index suggests that road dusts in this area are moderately to heavily polluted with Cd, Hg, and Sb. This study shows that plastic waste processing is a major source of toxic pollutants in road dusts in this area. Although the health risk from exposure to dust PBDEs was low, levels of some heavy metals in this dust exceeded acceptable risk levels for children and are of great concern.

Potential of select intermediate-volatility organic compounds and consumer products for secondary organic aerosol and ozone formation under relevant urban conditions

NASA Astrophysics Data System (ADS)

Li, Weihua; Li, Lijie; Chen, Chia-li; Kacarab, Mary; Peng, Weihan; Price, Derek; Xu, Jin; Cocker, David R.

2018-04-01

Emissions of certain low vapor pressure-volatile organic compounds (LVP-VOCs) are considered exempt to volatile organic compounds (VOC) regulations due to their low evaporation rates. However, these compounds may still play a role in ambient secondary organic aerosol (SOA) and ozone formation. The LVP-VOCs selected for this work are categorized as intermediate-volatility organic compounds (IVOCs) according to their vapor pressures and molecular formulas. In this study, the evaporation rates of 14 select IVOCs are investigated with half of them losing more than 95% of their mass in less than one month. Further, SOA and ozone formation are presented from 11 select IVOCs and 5 IVOC-containing generic consumer products under atmospherically relevant conditions using varying radical sources (NOx and/or H2O2) and a surrogate reactive organic gas (ROG) mixture. Benzyl alcohol (0.41), n-heptadecane (0.38), and diethylene glycol monobutyl ether (0.16) are determined to have SOA yields greater than 0.1 in the presence of NOx and a surrogate urban hydrocarbon mixture. IVOCs also influence ozone formation from the surrogate urban mixture by impacting radical levels and NOx availability. The addition of lab created generic consumer products has a weak influence on ozone formation from the surrogate mixture but strongly affects SOA formation. The overall SOA and ozone formation of the generic consumer products could not be explained solely by the results of the pure IVOC experiments.

Dielectric Studies on Binary Mixtures of Diethyl Ether (DEE) in Polar Solvents

NASA Astrophysics Data System (ADS)

Pradhan, S. K.; Dash, S. K.; Swain, M. D.; Swain, B. B.

2011-11-01

Dielectric constant (ɛ) of diethylether (DEE) in binary mixtures with four polar solvents such as n-butanl, i-butanol, t-butanol and tolune has been measured at 455 kHz and at a temperature 303.15 K. The refractive indices were measured at a regulated temperature by Pulfrich refractometer at sodium D-line. The data is used to evaluate mutual correlation factor gab, excess molar polarization and excess free energy of mixing ΔGab by using Winkelmann-Quitzsch equation for binary mixtures to asses the suitability of the polar solvents as modifiers. The trend of variation for these parameters exhibit marked dependence on the nature of alcohols. Diethylether is one of the solvent extractant used for the extraction and separation of zirconium and hafnium in reactor technology. The extractant is blended with appropriate polar modifiers for greater dispersal and more rapid phase disengagement. This facilitates in the elimination of the third organo-aqueous phase containing some of the metal ions. As such the study of molecular interaction among the component molecules has been undertaken in these binary mixtures using the dielectric route. The interaction parameters such as mutual correlation factor gab is found to be less than one in all alcohols, while it is negative in toluene upto 0.7 DEE molefraction and thereafter becoming positive. The nature of variation of the excess miolar polarization ΔP and excess free energy of mixing Gab tends to support the assessment of gab to choose a suitable polar modifier.

Dual roles of brain serine hydrolase KIAA1363 in ether lipid metabolism and organophosphate detoxification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nomura, Daniel K.; Fujioka, Kazutoshi; Issa, Roger S.

2008-04-01

Serine hydrolase KIAA1363 is an acetyl monoalkylglycerol ether (AcMAGE) hydrolase involved in tumor cell invasiveness. It is also an organophosphate (OP) insecticide-detoxifying enzyme. The key to understanding these dual properties was the use of KIAA1363 +/+ (wildtype) and -/- (gene deficient) mice to define the role of this enzyme in brain and other tissues and its effectiveness in vivo in reducing OP toxicity. KIAA1363 was the primary AcMAGE hydrolase in brain, lung, heart and kidney and was highly sensitive to inactivation by chlorpyrifos oxon (CPO) (IC{sub 50} 2 nM) [the bioactivated metabolite of the major insecticide chlorpyrifos (CPF)]. Although theremore » was no difference in hydrolysis product monoalkylglycerol ether (MAGE) levels in +/+ and -/- mouse brains in vivo, isopropyl dodecylfluorophosphonate (30 mg/kg) and CPF (100 mg/kg) resulted in 23-51% decrease in brain MAGE levels consistent with inhibition of AcMAGE hydrolase activity. On incubating +/+ and -/- brain membranes with AcMAGE and cytidine-5'-diphosphocholine, the absence of KIAA1363 activity dramatically increased de novo formation of platelet-activating factor (PAF) and lyso-PAF, signifying that metabolically-stabilized AcMAGE can be converted to this bioactive lipid in brain. On considering detoxification, KIAA1363 -/- mice were significantly more sensitive than +/+ mice to ip-administered CPF (100 mg/kg) and parathion (10 mg/kg) with increased tremoring and mortality that correlated for CPF with greater brain acetylcholinesterase inhibition. Docking AcMAGE and CPO in a KIAA1363 active site model showed similar positioning of their acetyl and trichloropyridinyl moieties, respectively. This study establishes the relevance of KIAA1363 in ether lipid metabolism and OP detoxification.« less

40 CFR 414.70 - Applicability; description of the bulk organic chemicals subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Monomethyl Ether *Dimer Acids Dioxane Ethane Ethylene Glycol Monophenyl Ether *Ethoxylates, Misc. Ethylene Glycol Dimethyl Ether Ethylene Glycol Monobutyl Ether Ethylene Glycol Monoethyl Ether Ethylene Glycol...

Comparative Study on Volatile Compounds of Alpinia japonica and Elettaria cardamomum.

PubMed

Asakawa, Yoshinori; Ludwiczuk, Agnieszka; Sakurai, Kazutoshi; Tomiyama, Kenichi; Kawakami, Yukihiro; Yaguchi, Yoshihiro

2017-08-01

The volatile compounds obtained from the ether extracts, headspace gases and steam distillates of Alpinia japonica and Elettaria cardamomum were analyzed by GC/MS. Both species were rich sources of naturally rare fenchane-type monoterpenoids, fenchene, fenchone, fenchyl alcohol and its acetate, together with 1,8-cineole. The distributions of volatile sesquiterpenoids were very poor in both species. Chiralities of fenchone in A. japonica and E. cardamomum were 99% of (1S,4R)-(+)-form. Camphor in A. japonica is composed of a mixture of (1R,4R)-(+)-form (94.3%) and (1S,4S)-(-)-form (5.7%). On the other hand, E. cardamomum produced only (1R,4R)-(+)-camphor (99%).

Interstellar molecules - Origin by catalytic reactions on grain surfaces. [compound distribution analysis

NASA Technical Reports Server (NTRS)

Anders, E.; Hayatsu, R.; Studier, M. H.

1974-01-01

To determine the compound distribution formed by surface catalysis, mixtures of CO, D2, and ND2 were heated with nickel-iron or montmorillonite clay catalysts for 49-214 hours at 250 to 300 C. Compounds identified include most of the known polyatomic interstellar molecules, as well as homologous series of acetylenes, dienes, alcohols, aldehydes, ketones, ethers, esters, nitriles, amines, etc., and cyclic compounds such as furans and pyrroles. These homologous series are uniquely characteristic of surface catalysis. A search for the heavier members of these series, predicted to occur at 1/10th to 1/1,000th the abundance of the lightest members, thus comprises a crucial test of this mechanism.

Library Design-Facilitated High-Throughput Sequencing of Synthetic Peptide Libraries.

PubMed

Vinogradov, Alexander A; Gates, Zachary P; Zhang, Chi; Quartararo, Anthony J; Halloran, Kathryn H; Pentelute, Bradley L

2017-11-13

A methodology to achieve high-throughput de novo sequencing of synthetic peptide mixtures is reported. The approach leverages shotgun nanoliquid chromatography coupled with tandem mass spectrometry-based de novo sequencing of library mixtures (up to 2000 peptides) as well as automated data analysis protocols to filter away incorrect assignments, noise, and synthetic side-products. For increasing the confidence in the sequencing results, mass spectrometry-friendly library designs were developed that enabled unambiguous decoding of up to 600 peptide sequences per hour while maintaining greater than 85% sequence identification rates in most cases. The reliability of the reported decoding strategy was additionally confirmed by matching fragmentation spectra for select authentic peptides identified from library sequencing samples. The methods reported here are directly applicable to screening techniques that yield mixtures of active compounds, including particle sorting of one-bead one-compound libraries and affinity enrichment of synthetic library mixtures performed in solution.

A direct numerical simulation of cool-flame affected autoignition in diesel engine-relevant conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krisman, Alex; Hawkes, Evatt R.; Talei, Mohsen

In diesel engines, combustion is initiated by a two-staged autoignition that includes both low- and high-temperature chemistry. The location and timing of both stages of autoignition are important parameters that influence the development and stabilisation of the flame. In this study, a two-dimensional direct numerical simulation (DNS) is conducted to provide a fully resolved description of ignition at diesel engine-relevant conditions. The DNS is performed at a pressure of 40 atmospheres and at an ambient temperature of 900 K using dimethyl ether (DME) as the fuel, with a 30 species reduced chemical mechanism. At these conditions, similar to diesel fuel,more » DME exhibits two-stage ignition. The focus of this study is on the behaviour of the low-temperature chemistry (LTC) and the way in which it influences the high-temperature ignition. The results show that the LTC develops as a “spotty” first-stage autoignition in lean regions which transitions to a diffusively supported cool-flame and then propagates up the local mixture fraction gradient towards richer regions. The cool-flame speed is much faster than can be attributed to spatial gradients in first-stage ignition delay time in homogeneous reactors. The cool-flame causes a shortening of the second-stage ignition delay times compared to a homogeneous reactor and the shortening becomes more pronounced at richer mixtures. Multiple high-temperature ignition kernels are observed over a range of rich mixtures that are much richer than the homogeneous most reactive mixture and most kernels form much earlier than suggested by the homogeneous ignition delay time of the corresponding local mixture. Altogether, the results suggest that LTC can strongly influence both the timing and location in composition space of the high-temperature ignition.« less

Gestational and Early Postnatal Exposure to an Environmentally Relevant Mixture of Brominated Flame Retardants: General Toxicity and Skeletal Variations.

PubMed

Tung, Emily W Y; Yan, Han; Lefèvre, Pavine L C; Berger, Robert G; Rawn, Dorothea F K; Gaertner, Dean W; Kawata, Alice; Rigden, Marc; Robaire, Bernard; Hales, Barbara F; Wade, Michael G

2016-06-01

Brominated flame retardants (BFRs) are stable environmental contaminants known to exert endocrine-disrupting effects. Developmental exposure to polybrominated diphenyl ethers (PBDEs) is correlated with impaired thyroid hormone signaling, as well as estrogenic and anti-androgenic effects. As previous studies have focused on a single congener or technical mixture, the purpose of the current study was to examine the effects of gestational and early postnatal exposure to an environmentally relevant mixture of BFRs designed to reflect house dust levels of PBDEs and hexabromocyclododecane on postnatal developmental outcomes. Pregnant Sprague-Dawley rats were exposed to the PBDE mixture from preconception to weaning (PND 21) through the diet containing 0, 0.75, 250, and 750 mg mixture/kg diet. BFR exposure induced transient reductions in body weight at PND 35 in male and from PND 30-45 in female offspring (250 and 750 mg/kg). Liver weights (PND 21) and xenobiotic metabolizing enzyme activities (PND 21 and 46) were increased in both male and female offspring exposed to 250 and 750 mg/kg diets. Furthermore, serum T4 levels were reduced at PND 21 in both,male and female offspring (250 and 750 mg/kg). At PND 21, Serum alkaline phosphatase (ALP) was decreased in males exposed to 750 mg/kg dietat, and females exposed to 250 and 750 mg/kg diets. At PND 46 ALP was significantly elevated in males (250 and 750 mg/kg). Variations in the cervical vertebrae and phalanges were observed in pups at PND 4 (250 and 750 mg/kg). Therefore, BFR exposure during gestation through to weaning alters developmental programming in the offspring. The persistence of BFRs in the environment remains a cause for concern with regards to developmental toxicity. © 2016 Wiley Periodicals, Inc.

Exposure to an environmentally relevant mixture of brominated flame retardants affects fetal development in Sprague-Dawley rats.

PubMed

Berger, Robert G; Lefèvre, Pavine L C; Ernest, Sheila R; Wade, Michael G; Ma, Yi-Qian; Rawn, Dorothea F K; Gaertner, Dean W; Robaire, Bernard; Hales, Barbara F

2014-06-05

Brominated flame retardants are incorporated into a wide variety of consumer products and are known to enter into the surrounding environment, leading to human exposure. There is accumulating evidence that these compounds have adverse effects on reproduction and development in humans and animal models. Animal studies have generally characterized the outcome of exposure to a single technical mixture or congener. Here, we determined the impact of exposure of rats prior to mating and during gestation to a mixture representative of congener levels found in North American household dust. Adult female Sprague-Dawley rats were fed a diet containing 0, 0.75, 250 or 750mg/kg of a mixture of flame retardants (polybrominated diphenyl ethers, hexabromocyclododecane) from two weeks prior to mating to gestation day 20. This formulation delivered nominal doses of 0, 0.06, 20 and 60mg/kg body weight/day. The lowest dose approximates high human exposures based on house dust levels and the dust ingestion rates of toddlers. Litter size and resorption sites were counted and fetal development evaluated. No effects on maternal health, litter size, fetal viability, weights, crown rump lengths or sex ratios were detected. The proportion of litters with fetuses with anomalies of the digits (soft tissue syndactyly or malposition of the distal phalanges) was increased significantly in the low (0.06mg/kg/day) dose group. Skeletal analysis revealed a decreased ossification of the sixth sternebra at all exposure levels. Thus, exposure to an environmentally relevant mixture of brominated flame retardants results in developmental abnormalities in the absence of apparent maternal toxicity. The relevance of these findings for predicting human risk is yet to be determined. Copyright © 2014. Published by Elsevier Ireland Ltd.

Gestational and Lactational Exposure to an Environmentally-Relevant Mixture of Brominated Flame Retardants: Effects on Neurodevelopment and Metabolism.

PubMed

Tung, Emily W Y; Kawata, Alice; Rigden, Marc; Bowers, Wayne J; Caldwell, Don; Holloway, Alison C; Robaire, Bernard; Hales, Barbara F; Wade, Michael G

2017-04-17

Developmental exposure to brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD), has been associated with impaired neurodevelopment and some symptoms of metabolic syndrome. However, there are inconsistencies in studies reporting neurodevelopmental effects with studies of pure substances more likely to report effects than studies of technical products. In addition, the influence of early BFR exposures on later development of metabolic disease-like symptoms has not been investigated. This study examined the effects of perinatal exposure to an environmentally relevant mixture of BFRs based on relative levels observed in house dust, on several markers of neurodevelopment and metabolism in offspring. Sprague-Dawley female rats were fed a diet estimated to deliver daily doses of 0, 0.06, 20, or 60 mg/kg of a mixture of PBDEs and HBCDD from before mating to weaning. Offspring were weaned to control diet and subjected to neurobehavioral and metabolic assessments. Exposure to BFRs decreased vertical movement in at postnatal day (PND) 32 and increased time to emerge to a lighted area on PND 105 in offspring of both sexes. Although early life exposure to the BFR mixture did not impact measures of glucose or insulin action, male offspring had significantly decreased fat pad weights at PND 46. Total cholesterol was increased in male and female offspring exposed to the highest dose at PND 21. These results suggest that gestational and lactational exposure to an environmentally relevant BFR mixture may induce changes in neurodevelopment and lipid metabolism in offspring. Birth Defects Research 109:497-512, 2017.© 2017 The Authors Birth Defects Research Published by Wiley Periodicals, Inc. © 2017 The Authors Birth Defects Research Published by Wiley Periodicals, Inc.

Gestational and Lactational Exposure to an Environmentally‐Relevant Mixture of Brominated Flame Retardants: Effects on Neurodevelopment and Metabolism

PubMed Central

Tung, Emily W. Y.; Kawata, Alice; Rigden, Marc; Bowers, Wayne J.; Caldwell, Don; Holloway, Alison C.; Robaire, Bernard; Hales, Barbara F.

2017-01-01

Background Developmental exposure to brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD), has been associated with impaired neurodevelopment and some symptoms of metabolic syndrome. However, there are inconsistencies in studies reporting neurodevelopmental effects with studies of pure substances more likely to report effects than studies of technical products. In addition, the influence of early BFR exposures on later development of metabolic disease‐like symptoms has not been investigated. This study examined the effects of perinatal exposure to an environmentally relevant mixture of BFRs based on relative levels observed in house dust, on several markers of neurodevelopment and metabolism in offspring. Methods Sprague–Dawley female rats were fed a diet estimated to deliver daily doses of 0, 0.06, 20, or 60 mg/kg of a mixture of PBDEs and HBCDD from before mating to weaning. Offspring were weaned to control diet and subjected to neurobehavioral and metabolic assessments. Results Exposure to BFRs decreased vertical movement in at postnatal day (PND) 32 and increased time to emerge to a lighted area on PND 105 in offspring of both sexes. Although early life exposure to the BFR mixture did not impact measures of glucose or insulin action, male offspring had significantly decreased fat pad weights at PND 46. Total cholesterol was increased in male and female offspring exposed to the highest dose at PND 21. Conclusions These results suggest that gestational and lactational exposure to an environmentally relevant BFR mixture may induce changes in neurodevelopment and lipid metabolism in offspring. Birth Defects Research 109:497–512, 2017.© 2017 The Authors Birth Defects Research Published by Wiley Periodicals, Inc. PMID:28398660

Effects of fomesafen, alone and in combination with an adjuvant, on plankton communities in freshwater outdoor pond mesocosms.

PubMed

Caquet, Thierry; Deydier-Stephan, Laurence; Lacroix, Gérard; Le Rouzic, Bertrand; Lescher-Moutoué, Françoise

2005-05-01

Ecotoxicological effects of the diphenyl ether herbicide fomesafen, applied alone or in combination with the adjuvant Agral 90 (mixture of polyethoxylated derivatives of nonylphenol), were assessed on planktonic communities in 18-m3 outdoor mesocosms during a nine-month study. Four mesocosms were treated with fomesafen only (nominal concentration: 40 microg/L), four were treated with the mixture fomesafen-Agral 90 (nominal concentration: 40 microg/L and 90 microg/L, respectively), and four were kept as the controls. Five treatments were performed every three weeks from April 18, 2000. Mean (+/- standard error [SE]) values of fomesafen concentration in water of 62.5 (+/-5.3) and 19.4 (+/-7.6) microg/L were measured at the end of the treatment period in fomesafen- and mixture-treated mesocosms, respectively. Fomesafen, either alone or in mixture with Agral 90, had a significant positive effect on the abundance and biovolume of Cyanobacteria, Cryptophyceae, Dinophyceae, and Bacillariophyceae. Chlorophyceae were inhibited by the herbicide and laboratory toxicity tests confirmed that green algae were more sensitive toward fomesafen than other algal classes. A positive effect of treatments on phytoplankton taxonomic diversity also was observed, indicating that, like natural disturbances of intermediate strength, xenobiotics sometimes may enhance the diversity of algal communities. Fomesafen alone did not have any clear effect on zooplankton. Abundance of calanoid copepods was reduced significantly in the mixture-treated ponds, suggesting either a direct effect of the adjuvant and/or an enhancement of herbicide toxicity by Agral 90. The abundance of other zooplanktonic herbivorous groups increased due to a reduced competition for food for herbivorous species and a higher availability of preys for predators. No algal bloom was observed in the treated ponds, presumably because of grazing pressure and the low availability of nutrients.

Peptide de novo sequencing of mixture tandem mass spectra

PubMed Central

Hotta, Stéphanie Yuki Kolbeck; Verano‐Braga, Thiago; Kjeldsen, Frank

2016-01-01

The impact of mixture spectra deconvolution on the performance of four popular de novo sequencing programs was tested using artificially constructed mixture spectra as well as experimental proteomics data. Mixture fragmentation spectra are recognized as a limitation in proteomics because they decrease the identification performance using database search engines. De novo sequencing approaches are expected to be even more sensitive to the reduction in mass spectrum quality resulting from peptide precursor co‐isolation and thus prone to false identifications. The deconvolution approach matched complementary b‐, y‐ions to each precursor peptide mass, which allowed the creation of virtual spectra containing sequence specific fragment ions of each co‐isolated peptide. Deconvolution processing resulted in equally efficient identification rates but increased the absolute number of correctly sequenced peptides. The improvement was in the range of 20–35% additional peptide identifications for a HeLa lysate sample. Some correct sequences were identified only using unprocessed spectra; however, the number of these was lower than those where improvement was obtained by mass spectral deconvolution. Tight candidate peptide score distribution and high sensitivity to small changes in the mass spectrum introduced by the employed deconvolution method could explain some of the missing peptide identifications. PMID:27329701

40 CFR 418.71 - Specialized definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... this subpart. (b) The term mixed fertilizer shall mean a mixture of wet and/or dry straight fertilizer materials, mixed fertilizer materials, fillers and additives prepared through chemical reaction to a given... STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Mixed and Blend Fertilizer Production Subcategory...

40 CFR 418.71 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... this subpart. (b) The term mixed fertilizer shall mean a mixture of wet and/or dry straight fertilizer materials, mixed fertilizer materials, fillers and additives prepared through chemical reaction to a given... STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Mixed and Blend Fertilizer Production Subcategory...

40 CFR 418.71 - Specialized definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... this subpart. (b) The term mixed fertilizer shall mean a mixture of wet and/or dry straight fertilizer materials, mixed fertilizer materials, fillers and additives prepared through chemical reaction to a given... STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Mixed and Blend Fertilizer Production Subcategory...

40 CFR 418.71 - Specialized definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... apply to this subpart. (b) The term mixed fertilizer shall mean a mixture of wet and/or dry straight fertilizer materials, mixed fertilizer materials, fillers and additives prepared through chemical reaction to... AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Mixed and Blend Fertilizer Production...

40 CFR 418.71 - Specialized definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... this subpart. (b) The term mixed fertilizer shall mean a mixture of wet and/or dry straight fertilizer materials, mixed fertilizer materials, fillers and additives prepared through chemical reaction to a given... STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Mixed and Blend Fertilizer Production Subcategory...

Developmental Exposure to a Commercial PBDE mixture, DE·71: Neurobehavioral, Hormonal, and Reproductive Effects

EPA Science Inventory

Developmental effects of PBDEs have been suspected due to their structural similarities to polychlorinated biphenyls (PCBs). This study evaluated neurobehavioral, hormonal, and reproductive effects in rat offspring perinatally exposed to a widely used pentabrominated commercial m...

A framework for evaluating mixture analysis algorithms

NASA Astrophysics Data System (ADS)

Dasaratha, Sridhar; Vignesh, T. S.; Shanmukh, Sarat; Yarra, Malathi; Botonjic-Sehic, Edita; Grassi, James; Boudries, Hacene; Freeman, Ivan; Lee, Young K.; Sutherland, Scott

2010-04-01

In recent years, several sensing devices capable of identifying unknown chemical and biological substances have been commercialized. The success of these devices in analyzing real world samples is dependent on the ability of the on-board identification algorithm to de-convolve spectra of substances that are mixtures. To develop effective de-convolution algorithms, it is critical to characterize the relationship between the spectral features of a substance and its probability of detection within a mixture, as these features may be similar to or overlap with other substances in the mixture and in the library. While it has been recognized that these aspects pose challenges to mixture analysis, a systematic effort to quantify spectral characteristics and their impact, is generally lacking. In this paper, we propose metrics that can be used to quantify these spectral features. Some of these metrics, such as a modification of variance inflation factor, are derived from classical statistical measures used in regression diagnostics. We demonstrate that these metrics can be correlated to the accuracy of the substance's identification in a mixture. We also develop a framework for characterizing mixture analysis algorithms, using these metrics. Experimental results are then provided to show the application of this framework to the evaluation of various algorithms, including one that has been developed for a commercial device. The illustration is based on synthetic mixtures that are created from pure component Raman spectra measured on a portable device.

Laser-Induced Periodic Surface Structures on P3HT and on Its Photovoltaic Blend with PC71BM.

PubMed

Cui, Jing; Rodríguez-Rodríguez, Álvaro; Hernández, Margarita; García-Gutiérrez, Mari-Cruz; Nogales, Aurora; Castillejo, Marta; Moseguí González, Daniel; Müller-Buschbaum, Peter; Ezquerra, Tiberio A; Rebollar, Esther

2016-11-23

We describe the conditions for optimal formation of laser-induced periodic surface structures (LIPSS) over poly(3-hexylthiophene) (P3HT) spin-coated films. Optimal LIPSS on P3HT are observed within a particular range of thicknesses and laser fluences. These conditions can be translated to the photovoltaic blend formed by the 1:1 mixture of P3HT and [6,6]-phenyl C 71 -butyric acid methyl ester (PC 71 BM) when deposited on an indium tin oxide (ITO) electrode coated with (poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS). Solar cells formed by using either a bilayer of P3HT structured by LIPSS covered by PC 71 BM or a bulk heterojunction with a P3HT:PC 71 BM blend structured by LIPSS exhibit generation of electrical photocurrent under light illumination. These results suggest that LIPSS could be a compatible technology with organic photovoltaic devices.

Incorporation de particules de verre post-consommation dans un enrobe bitumineux de type ESG14

NASA Astrophysics Data System (ADS)

Lachance Tremblay, Eric

In 2008, around 244,000 tons of glass was produced by the Quebec population. From this number, 128,000 tons were collected by various means of collection. Glass recycling is problematic because all the glass that cannot be classified according to the type can't be used to manufacture new products. It is therefore necessary to find new sources of uses for this material. Because the use of recycled materials in road structure material is beneficial from an environmental and sometimes structural point of view, the idea of using recycled glass into asphalt mixture was recently studied at the LCMB. Nowadays, the use of recycled glass in asphalt mixture is not regulated by the MTQ. This research goal was to verify the possibility of using recycled glass particles in a ESG14 asphalt mixture while maintaining equivalent properties and performance compared to a conventional mix. Different dosages of recycled glass particles have been studied to evaluate the effect of glass on the asphalt mixture volumetric characteristics, the ability of compaction and the rutting resistance. These mixes were formulated according to the LC formulation of the MTQ. The first part allowed selecting an optimal dosage of recycled glass particles. Thereafter, the thermo mechanical performance (resistance to low temperatures (TSRST), complex modulus (E*) and resistance to fatigue cracking), physical characteristics (macro texture and surface grip) and durability (resistance to water damage) of the asphalt mixture with the optimal dosage were evaluated and compared with a reference mixture. The results show that the ESG14 mixture with recycled glass formulated with the LC method is more susceptible to rutting than the reference mixture. Therefore, a reduction of the bitumen content can increase the rutting resistance while conserving equivalent properties to a conventional mix regarding resistance to low temperatures, complex modulus, resistance to fatigue cracking as well as the physical characteristics. Therefore, the use of recycled in glass seems to modify the asphalt behavior and increase the moisture susceptibility.

Molecular structure impacts on secondary organic aerosol formation from glycol ethers

NASA Astrophysics Data System (ADS)

Li, Lijie; Cocker, David R.

2018-05-01

Glycol ethers, a class of widely used solvents in consumer products, are often considered exempt as volatile organic compounds based on their vapor pressure or boiling points by regulatory agencies. However, recent studies found that glycol ethers volatilize at ambient conditions nearly as rapidly as the traditional high-volatility solvents indicating the potential of glycol ethers to form secondary organic aerosol (SOA). This is the first work on SOA formation from glycol ethers. The impact of molecular structure, specifically -OH, on SOA formation from glycol ethers and related ethers are investigated in the work. Ethers with and without -OH, with methyl group hindrance on -OH and with -OH at different location are studied in the presence of NOX and under "NOX free" conditions. Photooxidation experiments under different oxidation conditions confirm that the processing of ethers is a combination of carbonyl formation, cyclization and fragmentation. Bulk SOA chemical composition analysis and oxidation products identified in both gas and particle phase suggests that the presence and location of -OH in the carbon bond of ethers determine the occurrence of cyclization mechanism during ether oxidation. The cyclization is proposed as a critical SOA formation mechanism to prevent the formation of volatile compounds from fragmentation during the oxidation of ethers. Glycol ethers with -CH2-O-CH2CH2OH structure is found to readily form cyclization products, especially with the presence of NOx, which is more relevant to urban atmospheric conditions than without NOx. Glycol ethers are evaluated as dominating SOA precursors among all ethers studied. It is estimated that the contribution of glycol ethers to anthropogenic SOA is roughly 1% of the current organic aerosol from mobile sources. The contribution of glycol ethers to anthropogenic SOA is roughly 1% of the current organic aerosol from mobile sources and will play a more important role in future anthropogenic SOA formation.

[The effect of diet ratio of polyunsaturated fatty acids of omega-3 and omega-6 families on activity of aminotransferases and gamma-glutamyltransferase in rat blood serum].

PubMed

Ketsa, O V; Marchenko, M M

2014-01-01

The effect of diet fat compositions with various ratio of omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) on alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyltransferase (GGT) activities in blood serum of 45 white mongrel rats weighing 90-110 g (9 animals in group) has been investigated. Fat components in the semi-synthetic diet, compiled on the basis of AIN-93 diet, and sources of omega-6 and omega-3 PUFA were presented by sunflower oil, soybean oil and fish oil. It has been shown that four-week inclusion of linoleic acid (LA) and alpha-linolenic acid (alpha-LNA) in a ratio of 7:1 into the diet (soybean oil) as well as use of only omega-6 PUFA (sunflower oil) has lead to an increase in the activity of ALT and GGT in rat blood serum compared to control animals treated with the complex of linolenic, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid through the mixture of sunflower oil and fish oil (9:1) with the ratio of omega-6 and omega-3 PUFA 7:1. Along with this, the AST:ALT ratio (de Ritis ratio) was lower (p < 0.05) as compared with the control group of rat, amounting respectively 0.92 +/- 0.08 and 0.79 +/- 0.12 vs 1.26 +/- 0.10. The use of high doses of omega-3 fatty acids (600 mg EPA and 400 mg DHA per kg of animal weight per day coming through fish oil) did not affect the activity of ALT and GGT, but increased AST serum activity (0.47 +/- 0.04 micromoles/min per mg protein) and the de Ritis ratio (2.53 +/- 0.23). The diet deprived with fat increased enzyme activity of ALT, AST and GGT in rat blood serum.

[Prevalence of microsporidia and other intestinal parasites in patients with HIV infection, Bogota, 2001].

PubMed

Flórez, Astrid Carolina; García, Dabeiba Adriana; Moncada, Ligia; Beltrán, Mauricio

2003-09-01

Opportunistic intestinal parasites are a common cause of diarrhea in HIV-infected patients. To determine the prevalence of microsporidia and other opportunistic parasites infecting HIV patients in Bogotá, Colombia, 115 patients were examined for these infections during the year 2001. The institution and the sample percent from each are as follows: Santa Clara Hospital, 33.0%; San Pedro Claver, 20.0%; Simón Bolívar Hospital, 14.8%; San José Hospital, 13.9%; Central de la Policía Hospital, 6.1%; Compensar, 5.2%; Colombian League against AIDS, 2.6%; San Ignacio Hospital, 2.6%, and the Military Hospital, 1.7%. The average patient age was 36 years, with a range from 18 to 71 years. Patients with complaint of gastrointestinal symptoms were asked to provide two consecutive stool samples. The samples were concentrated in formalin-ether and examined microscopically for intestinal coccidian parasites by direct wet slide mounts. The prevalence of intestinal opportunistic parasites was 10.4% for Cryptosporidium sp. Initially, 29% of the samples were found to be positive for microsporidian spores using a modified Ziehl Neelsen chromotrope stain, but only 3.5% of them were confirmed as positive when a calcofluor/Gram chromotrope stain was used. The general prevalence of intestinal parasites was 59.1%. The most frequently found pathogens were Blastocystis hominis, 25.2%, and Entamoeba histolytica, 13%. In other studies with HIV patients in Colombia, lower prevalences of Cryptosporidium sp. infection were observed.

A fluorescence-based method for rapid and direct determination of polybrominated diphenyl ethers in water

DOE PAGES

Shan, Huimei; Liu, Chongxuan; Wang, Zheming; ...

2015-01-01

A new method was developed for rapid and direct measurement of polybrominated diphenyl ethers (PBDEs) in aqueous samples using fluorescence spectroscopy. The fluorescence spectra of tri- to deca-BDE (BDE 28, 47, 99, 153, 190, and 209) commonly found in environment were measured at variable emission and excitation wavelengths. The results revealed that the PBDEs have distinct fluorescence spectral profiles and peak positions that can be exploited to identify these species and determine their concentrations in aqueous solutions. The detection limits as determined in deionized water spiked with PBDEs are 1.71-5.82 ng/L for BDE 28, BDE 47, BDE 190, and BDEmore » 209 and 45.55–69.95 ng/L for BDE 99 and BDE 153. The effects of environmental variables including pH, humic substance, and groundwater chemical composition on PBDEs measurements were also investigated. These environmental variables affected fluorescence intensity, but their effect can be corrected through linear additivity and separation of spectral signal contribution. Compared with conventional GC-based analytical methods, the fluorescence spectroscopy method is more efficient as it only uses a small amount of samples (2-4 mL), avoids lengthy complicated concentration and extraction steps, and has a low detection limit of a few ng/L.« less

Preliminary health risk assessment for polybrominated diphenyl ethers and polybrominated dibenzo-p-dioxins/furans in seafood from Guangzhou and Zhoushan, China.

PubMed

Miyake, Yuichi; Jiang, Qinting; Yuan, Wang; Hanari, Nobuyasu; Okazawa, Tsuyoshi; Wyrzykowska, Barbara; So, Man Ka; Lam, Paul K S; Yamashita, Nobuyoshi

2008-01-01

Dietary intake is one of the important routes of human exposure to brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs). The use of PBDEs may also result in exposure to polybrominated dibenzo-p-dioxins and dibenzofurans (PBDDs/DFs), as these compounds are impurities in technical mixtures of BFRs and can also be formed unintentionally by the same processes that generate chlorinated dioxins. This study determined the concentrations of polybrominated compounds in common seafood in Guangzhou and Zhoushan, and assessed the health risks of these chemicals via consumption of contaminated seafood. Seafood samples (fish, bivalves, shrimp, crab, and cephalopods) purchased from local markets in 2003 and 2004 were analyzed for PBDEs and PBDDs/DFs. The highest concentration of total PBDEs (46.3 ng g(-1) lipid wt.) was detected in fish from Guangzhou, in which BDEs 47 and 209 were the two predominant congeners. The total daily intakes of PBDEs, PBDDs, and PBDFs were, 946, 6.39, and 6.54 pg kg(-1) body weight (bw) in Guangzhou, and 489, 4.99, and 7.65 pg kg(-1) bw in Zhoushan, respectively. The hazard ratios for PBDDs and PBDFs were both greater than unity, indicating that these compounds may pose some health risks to the local population.

Monounsaturated fatty acid ether oligomers formed during heating of virgin olive oil show agglutination activity against human red blood cells.

PubMed

Patrikios, Ioannis S; Mavromoustakos, Thomas M

2014-01-29

The present work focuses on the characterization of molecules formed when virgin olive oil is heated at 130 °C for 24 h open in air, which are found to be strong agglutinins. The hemagglutinating activity of the newly formed molecule isolated from the heated virgin olive oil sample was estimated against human red blood cells (RBCs). Dimers and polymers (high molecular weight molecules) were identified through thin layer chromatography (TLC) of the oil mixture. (1)H and (13)C nuclear magnetic resonance (NMR) and gas chromatography-mass spectroscopy (GC-MS) were the methods used for structural characterization. Among others, oligomerization of at least two monounsaturated fatty acids (FA) by an ether linkage between the hydrocarbon chains is involved. Light microscopy was used to characterize and visualize the agglutination process. Agglutination without fusion or lysis was observed. It was concluded that the heating of virgin olive oil open in air, among other effects, produces oligomerization as well as polymerization of unsaturated FA, possibly of monohydroxy, monounsaturated FA that is associated with strong hemagglutinating activity against human RBCs. The nutritional value and the effects on human health of such oligomers are not discussed in the literature and remain to be investigated.

Separation of mutagenic components in synthetic crudes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guerin, M. R.; Ho, C. H.; Clark, B. R.

1978-01-01

Mutagenic, basic constituents of a synthetic coal oil and a shale oil were isolated from the crude mixtures. In arriving at an efficient isolation procedure, several liquid chromatographic packing-eluent combinations were tried and the fractions bioassayed to determine the distributions of the mutagenic components. The most effective separation was achieved using a sequential elution scheme with first an alumina-benzene combination followed by a Sephadex LH-20 gel-isopropanol-acetone system. About 75 to 80% of an ether soluble base is eluted with benzene through alumina (activity I). Analysis of this fraction has revealed a wide range of alkyl substituted quinolines and pyridines. Materialmore » remaining on the alumina column was eluted with ethanol, dried and placed on the Sephadex column. Isopropanol (approximately 250 ml) and acetone (approximately 600 ml) were used in that order to elute the material quantitatively. About 12% of the ether-soluble base is eluted with the isopropanol while the rest (approximately 10%) is eluted with the acetone. Additional alkyl pyridine compounds are eluted with isopropanol while the acetone fractions are predominantly multi-ring nitrogen heterocyclic compounds, according to mass spectral analyses. Bioassay data show excellent isolation of the mutagenic activities into the acetone fractions. Negligible activity is found in the sum of the other (90% wt) fractions.« less

Long Duration Life Test of Propylene Glycol Water Based Thermal Fluid Within Thermal Control Loop

NASA Technical Reports Server (NTRS)

Le, Hung; Hill, Charles; Stephan, Ryan A.

2010-01-01

Evaluations of thermal properties and resistance to microbial growth concluded that 50% Propylene Glycol (PG)-based fluid and 50% de-ionized water mixture was desirable for use as a fluid within a vehicle s thermal control loop. However, previous testing with a commercial mixture of PG and water containing phosphate corrosion inhibitors resulted in corrosion of aluminum within the test system and instability of the test fluid. This paper describes a follow-on long duration testing and analysis of 50% Propylene Glycol (PG)-based fluid and 50% de-ionized water mixture with inorganic corrosion inhibitors used in place of phosphates. The test evaluates the long-term fluid stability and resistance to microbial and chemical changes

Isolation and characterization of an ether-type polyurethane-degrading micro-organism and analysis of degradation mechanism by Alternaria sp.

PubMed

Matsumiya, Y; Murata, N; Tanabe, E; Kubota, K; Kubo, M

2010-06-01

To degrade ether-type polyurethane (ether-PUR), ether-PUR-degrading micro-organism was isolated. Moreover, ether-PUR-degrading mechanisms were analysed using model compounds of ether-PUR. A fungus designated as strain PURDK2, capable of changing the configuration of ether-PUR, has been isolated. This isolated fungus was identified as Alternaria sp. Using a scanning electron microscope, the grid structure of ether-PUR was shown to be melted and disrupted by the fungus. The degradation of ether-PUR by the fungus was analysed, and the ether-PUR was degraded by the fungus by about 27.5%. To analyse the urethane-bond degradation by the fungus, a degraded product of ethylphenylcarbamate was analysed using GC/MS. Aniline and ethanol were detected by degradation with the supernatant, indicating that the fungus secreted urethane-bond-degrading enzyme(s). PURDK2 also degraded urea bonds when diphenylmethane-4,4'-dibutylurea was used as a substrate. The enzyme(s) from PURDK2 degraded urethane and urea bonds to convert the high molecular weight structure of ether-PUR to small molecules; and then the fungus seems to use the small molecules as an energy source. Ether-PUR-degrading fungus, strain PURDK2, was isolated, and the urethane- and urea-bonds-degrading enzymes from strain PURDK2 could contribute to the material recycling of ether-PUR.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

Phillips Petroleum Co. is poised to license its high conversion process to produce fuel ethers for blending in reformulated gasolines. The technology has been proven in a Phillips semiworks at Bartlesville, Okla. The process can produce methyl tertiary butyl ether, ethyl tertiary butyl ether, tertiary amyl methyl ether, or tertiary amyl ethyl ether with typical refinery process equipment and techniques. Phillips said it can achieve conversion levels of 92-99%, depending on the ether. The ether produced is determined by which hydrocarbon fraction is used for feedstock and which alcohol is chosen for reaction. The process is described.

Solvent-Polarity-Induced Active Layer Morphology Control in Crystalline Diketopyrrolopyrrole-Based Low Band Gap Polymer Photovoltaics

NASA Astrophysics Data System (ADS)

Ferdous, Sunzida; Liu, Feng; Wang, Dong; Russell, Thomas

2014-03-01

The effects of various processing solvents on the morphology of diketopyrrolopyrrole (DPP)-based low band gap polymer (PDPPBT) and phenyl-C71-butyric acid methyl ester (PC71BM) blends are studied. The quality of the processing solvents was varied systematically using a mixture of a non-aromatic polar primary solvent with high boiling point secondary solvents of increasing polarities. An unfavorable solvent-PC71BM interaction affects the growth process of polymer crystallites inside the blend. When non-aromatic polar solvent was used, large PC71BM aggregates were formed that increase in size with the addition of non-polar secondary solvents. When polar solvents were instead used as the secondary solvents, the size scales of the aggregates decrease markedly, creating a percolated fibrillar network. Power conversion efficiencies of 0.03% to 5% are obtained, depending on the solvent system used.

Gibbs energies of transferring triglycine from water into H2O-DMSO solvent

NASA Astrophysics Data System (ADS)

Usacheva, T. R.; Kuz'mina, K. I.; Lan, Pham Thi; Kuz'mina, I. A.; Sharnin, V. A.

2014-08-01

The Gibbs energies of transferring triglycine (3Gly, glycyl-glycyl-glycine) from water into mixtures of water with dimethyl sulfoxide (χDMSO = 0.05, 0.10, and 0.15 mole fractions) at 298.15 K are determined from the interphase distribution. An increased dimethyl sulfoxide (DMSO) concentration in the solvent slightly raises the positive values of Δtr G ○(3Gly), possibly indicating the formation of more stable 3Gly-H2O solvated complexes than ones of 3Gly-DMSO. It is shown that the change in the Gibbs energy of transfer of 3Gly is determined by the enthalpy component. The relationship of 3Gly and 18-crown-6 ether (18C6) solvation's contributions to the change in the Gibbs energy of [3Gly18C6] molecular complex formation in H2O-DMSO solvents is analyzed, and the key role of 3Gly solvation's contribution to the change in the stability of [3Gly18C6] upon moving from H2O to mixtures with DMSO is revealed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Fei; He, Yadong; Huang, Jingsong

Porous liquids are a promising new class of materials featuring nanoscale cavity units dispersed in liquids that are suitable for applications such as gas storage and separation. In this work, we use molecular dynamics simulations to examine the multicomponent gas storage in a porous liquid consisting of crown-ether-substituted cage molecules dissolved in a 15-crown-5 solvent. We compute the storage of three prototypical small molecules including CO 2, CH 4, and N 2 and their binary mixtures in individual cage molecules. For porous liquids in equilibrium with a binary 1:1 gas mixture bath with partial gas pressure of 27.5 bar, amore » cage molecule shows a selectivity of 4.3 and 13.1 for the CO 2/CH 4 and CO 2/N 2 pairs, respectively. We provide a molecular perspective of how gas molecules are stored in the cage molecule and how the storage of one type of gas molecule is affected by other types of gas molecules. Finally, our results clarify the molecular mechanisms behind the selectivity of such cage molecules toward different gases.« less

Isolation, identification and usefulness of antifungal compounds from Zuccagnia punctata for control of toxigenic ear rot pathogens.

PubMed

Jimenez, Cristina M; Sampietro, Diego A; Sgariglia, Melina A; Soberón, José R; Vattuone, Marta A

2014-10-01

Infusion, tincture and decoction of leaves of Zuccagnia punctata Cav. were assayed on growth of Fusarium verticillioides, F. graminearum sensu stricto, F. boothii, F. meridionale, F. subglutinans and F. thapsinum. The tincture showed the lowest IC50 on mycelial growth. A diethyl ether fraction of the tincture showed the highest antifungal activity in microdilution assays on F. verticillioides and F. graminearum. The antifungal constituents were separated by silica gel chromatography and identified as 2',4'-dihydroxychalcone, 2',4'-dihydroxy-3'-methoxychalcone and 7-hydroxy-3',4'-dimethoxyflavone. These chalcones had the lowest MIC and MFC values on F. verticillioides and F. graminearum sensu stricto. 2',4'-Dihydroxychalcone was mildly toxic and the remaining identified compounds were non-toxic in the brine shrimp assay. 2',4'-Dihydroxychalcone in mixtures with commercial food preservatives showed additive effects on F. graminearum sensu stricto and synergistic ones on F. verticillioides. 2',4'-Dihydroxy-3'-methoxychalcone showed synergistic effects in mixtures. Our results suggest that addition of chalcones to food preservatives allows reduction in the doses of the preservatives required for control of Fusarium species.

Volumetric Properties, Viscosities, and Refractive Indices of the Binary Systems 1-Butanol + PEG 200, + PEG 400, and + TEGDME

NASA Astrophysics Data System (ADS)

Živković, N.; Šerbanović, S.; Kijevčanin, M.; Živković, E.

2013-06-01

Densities, viscosities, and refractive indices of three binary systems consisting of 1-butanol with polyethylene glycols of different molecular weights (PEG 200 and PEG 400) or tetraethylene glycol dimethyl ether (TEGDME) were measured at ten temperatures (288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, 323.15, 328.15, and 333.15) K and atmospheric pressure. Densities of the selected binary mixtures were measured with an Anton Paar DMA 5000 digital vibrating U-tube densimeter, refractive indices were measured with an automatic Anton Paar RXA-156 refractometer, while for viscosity measurements, a digital Stabinger SVM 3000/G2 viscometer was used. From these data, excess molar volumes were calculated and fitted to the Redlich-Kister equation. The obtained results have been analyzed in terms of specific molecular interactions and mixing behavior between mixture components, as well as the influence of temperature on them. Viscosity data were also correlated by Grunberg-Nissan, Eyring-UNIQUAC, three-body McAlister, and Eyring-NRTL models.

Evaluation of transcutol as a clonazepam transdermal permeation enhancer from hydrophilic gel formulations.

PubMed

Mura, P; Faucci, M T; Bramanti, G; Corti, P

2000-02-01

The influence of diethyleneglycol monoethyl ether (transcutol), alone or in combination with propylene glycol, on clonazepam permeation through an artificial membrane and excised rabbit ear skin from Carbopol hydrogels was investigated. Drug kinetic permeation parameters were determined for both series of experiments and compared. Rheological characteristics, drug solubility and membrane/vehicle partition coefficient for each gel formulation were also determined, and their role in the formulation performance was investigated. Both series of experiments showed an increase of drug permeation as a function of transcutol content in the formulation. The combination of transcutol and propylene glycol resulted in a synergistic enhancement of clonazepam flux. A different trend was found in experiments with gels containing mixtures of the two enhancers, where an increase (in the case of artificial membrane) or a decrease (in the case of rabbit ear skin) of drug permeation was found by increasing the transcutol/propylene glycol ratio in the mixture. Such a result is explained on the basis of the particular mechanism of action demonstrated for transcutol which associates the increase of drug solubility to the potent effect of a depot in the skin.

Synthesis, characterisation and computational studies on a novel one-dimensional arrangement of Schiff-base Mn3 single-molecule magnet.

PubMed

Lin, Po-Heng; Gorelsky, Serge; Savard, Didier; Burchell, Tara J; Wernsdorfer, Wolfgang; Clérac, Rodolphe; Murugesu, Muralee

2010-09-07

The syntheses, structures and magnetic properties are reported for three new manganese complexes containing the Schiff-base ((2-hydroxy-3-methoxyphenyl)methylene)isonicotinohydrazine (H(2)hmi) ligand. Complex [Mn(II)(H(2)hmi)(2)(MeOH)(2)Cl(2)] (1) was obtained from the reaction of H(2)hmi with MnCl(2) in a MeOH-MeCN mixture. Addition of triethylamine to the previous reaction mixture followed by diethyl ether diffusion yielded a dinuclear manganese [Mn(III)(2)(hmi)(2)(OMe)(2)](infinity).2MeCN.2OEt(2) (2) compound. Upon increasing the MnCl(2)/H(2)hmi ratio, the mixed valence complex [Mn(III)(2)Mn(II)(hmi)(2)(OMe)(2)Cl(2)](infinity).MeOH (3) was obtained. Dc and ac magnetic measurements were carried out on all three samples. The ac susceptibility and field dependence of the magnetisation measurements confirmed that complex 3 exhibits a single-molecule magnet behaviour with an effective energy barrier of 8.1 K and an Arrhenius pre-exponential factor of 3 x 10(-9) s.

Multicomponent Gas Storage in Organic Cage Molecules

DOE PAGES

Zhang, Fei; He, Yadong; Huang, Jingsong; ...

2017-05-18

Porous liquids are a promising new class of materials featuring nanoscale cavity units dispersed in liquids that are suitable for applications such as gas storage and separation. In this work, we use molecular dynamics simulations to examine the multicomponent gas storage in a porous liquid consisting of crown-ether-substituted cage molecules dissolved in a 15-crown-5 solvent. We compute the storage of three prototypical small molecules including CO 2, CH 4, and N 2 and their binary mixtures in individual cage molecules. For porous liquids in equilibrium with a binary 1:1 gas mixture bath with partial gas pressure of 27.5 bar, amore » cage molecule shows a selectivity of 4.3 and 13.1 for the CO 2/CH 4 and CO 2/N 2 pairs, respectively. We provide a molecular perspective of how gas molecules are stored in the cage molecule and how the storage of one type of gas molecule is affected by other types of gas molecules. Finally, our results clarify the molecular mechanisms behind the selectivity of such cage molecules toward different gases.« less

Organo-halogenated contaminants (OHCs) in the sediments from the Soan River, Pakistan: OHCs(adsorbed TOC) burial flux, status and risk assessment.

PubMed

Malik, Riffat Naseem; Mehboob, Fouzia; Ali, Usman; Katsoyiannis, Athanasios; Schuster, Jasmin K; Moeckel, Claudia; Jones, Kevin C

2014-05-15

In this study, regression analysis revealed that TOC is the principal factor in controlling the fate of organo-halogenated contaminants (OHCs: PCBs, PBDEs, OCPs) in Soan River, Pakistan. The OHCs(adsorbed TOC) burial flux (OHCs(adsorbed TOC)Bf; mg/cm(2)·yr) was calculated in the following ranges: ∑PCBs (0.07-0.31), ∑PBDEs (0.005-0.029), ∑HCHs (0.015-0.046) and ∑DDTs (0.007-0.039). Apart from OHCs(adsorbed TOC)Bf, the levels of OHCs were in the following order: PCBs>DDTs>PBDEs>HCH>Chlordane>HCB. PBDEs and PCB congener patterns showed following order respectively: BDE-149>-153>-18>-138>-44 and PCB-149>-153>-18>-138>-44. DDT isomers and metabolites' pattern were p,p'-DDT>p,p'-DDD>p,p'-DDE>o,p'-DDT>o,p'-DDD>o,p'-DDE and HCHs were β-HCH>α-HCH>γ-HCH>δ-HCH. PBDE composition had similarities to penta-BDE and DE-71 mixtures and PCBs with commercial products Aroclor-1254 and -1260. (DDE+DDD)/∑DDTs and p,p'-DDT/p,p'-DDE suggested the recent input of DDTs in sediments while α/γ-HCH indicated past usage of lindane and technical mixtures. Risk assessment suggested that Soan River and its tributaries are potentially at risk against most of the OHCs. Copyright © 2014 Elsevier B.V. All rights reserved.

A new route to synthesize aryl acetates from carbonylation of aryl methyl ethers

PubMed Central

Yang, Youdi; Li, Shaopeng; Han, Buxing

2018-01-01

Ether bond activation is very interesting because the synthesis of many valuable compounds involves conversion of ethers. Moreover, C–O bond cleavage is also very important for the transformation of biomass, especially lignin, which abundantly contains ether bonds. Developing efficient methods to activate aromatic ether bonds has attracted much attention. However, this is a challenge because of the inertness of aryl ether bonds. We proposed a new route to activate aryl methyl ether bonds and synthesize aryl acetates by carbonylation of aryl methyl ethers. The reaction could proceed over RhCl3 in the presence of LiI and LiBF4, and moderate to high yields of aryl acetates could be obtained from transformation of various aryl methyl ethers with different substituents. It was found that LiBF4 could assist LiI to cleave aryl methyl ether bonds effectively. The reaction mechanism was proposed by a combination of experimental and theoretical studies. PMID:29795781

Probing the antagonistic effect of toluene as a component in surrogate fuel models at low temperatures and high pressures. A case study of toluene/dimethyl ether mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yingjia; Somers, Kieran P.; Mehl, Marco

There is a dearth of experimental data which examine the fundamental low-temperature ignition (T < 900 K) behavior of toluene resulting in a lack of data for the construction, validation, and interpretation of chemical kinetic models for commercial fuels. In order to gain a better understanding of its combustion chemistry, dimethyl ether (DME) has been used as a radical initiator to induce ignition in this highly knock resistant aromatic, and its influence on the combustion of toluene ignition was studied in both shock tube and rapid compression machines as a function of temperature (624–1459 K), pressure (20–40 atm), equivalence ratiomore » (0.5–2.0), and blending ratio (100% toluene, 76% toluene (76T/24D), 58% toluene (58T/42D), 26% toluene (26T/74D) and 100% DME). We use several literature chemical kinetic models to interpret our experimental results. For mixtures containing high concentrations of toluene at low-temperatures none of these are capable of reproducing experiment. This then implies an incomplete understanding of the low-temperature oxidation pathways which control its ignition in our experimental reactors, and by extension, in spark- (SI) and compression-ignition (CI) engines, and an updated detailed chemical kinetic model is presented for engineering applications. Model analyses indicate that although the initial fate of the fuel is dominated by single-step H-atom abstraction reactions from both the benzylic and phenylic sites, the subsequent fate of the allylic and vinylic radicals formed is much more complex. Further experimental and theoretical endeavors are required to gain a holistic qualitative and quantitative chemical kinetics based understanding of the combustion of pure toluene, toluene blends, and commercial fuels containing other aromatic components, at temperatures of relevance to SI and CI engines.« less

Probing the antagonistic effect of toluene as a component in surrogate fuel models at low temperatures and high pressures. A case study of toluene/dimethyl ether mixtures

DOE PAGES

Zhang, Yingjia; Somers, Kieran P.; Mehl, Marco; ...

2016-07-12

There is a dearth of experimental data which examine the fundamental low-temperature ignition (T < 900 K) behavior of toluene resulting in a lack of data for the construction, validation, and interpretation of chemical kinetic models for commercial fuels. In order to gain a better understanding of its combustion chemistry, dimethyl ether (DME) has been used as a radical initiator to induce ignition in this highly knock resistant aromatic, and its influence on the combustion of toluene ignition was studied in both shock tube and rapid compression machines as a function of temperature (624–1459 K), pressure (20–40 atm), equivalence ratiomore » (0.5–2.0), and blending ratio (100% toluene, 76% toluene (76T/24D), 58% toluene (58T/42D), 26% toluene (26T/74D) and 100% DME). We use several literature chemical kinetic models to interpret our experimental results. For mixtures containing high concentrations of toluene at low-temperatures none of these are capable of reproducing experiment. This then implies an incomplete understanding of the low-temperature oxidation pathways which control its ignition in our experimental reactors, and by extension, in spark- (SI) and compression-ignition (CI) engines, and an updated detailed chemical kinetic model is presented for engineering applications. Model analyses indicate that although the initial fate of the fuel is dominated by single-step H-atom abstraction reactions from both the benzylic and phenylic sites, the subsequent fate of the allylic and vinylic radicals formed is much more complex. Further experimental and theoretical endeavors are required to gain a holistic qualitative and quantitative chemical kinetics based understanding of the combustion of pure toluene, toluene blends, and commercial fuels containing other aromatic components, at temperatures of relevance to SI and CI engines.« less

High-performance thin-layer chromatographic methods for the determination of febuxostat and febuxostat/diclofenac combination in human plasma.

PubMed

El-Yazbi, Fawzi A; Amin, Omayma A; El-Kimary, Eman I; Khamis, Essam F; Younis, Sameh E

2018-06-01

Two simple, sensitive and specific high-performance thin-layer chromatographic (HPTLC) methods were developed for the determination of febuxostat (FEB) individually, and simultaneously with diclofenac (DIC) in human plasma. Method A presents the first HPTLC-ultraviolet attempt for FEB determination in human plasma. FEB was separated from endogenous plasma components (at hR F  = 70) with ethyl acetate-methanol-water (9:2:1, v/v) mixture as mobile phase and quantified by densitometry at its λ max (315 nm). Method B is considered the first attempt for the simultaneous determination of FEB and DIC in human plasma. A mixture of petroleum ether-chloroform-ethyl acetate-formic acid (7.5:1:2.5:0.25, v/v) was used as the mobile phase. The two drugs were separated at hR F of 39 and 60 for FEB and DIC, respectively. FEB and DIC were quantified by densitometry at their isoabsorptive point (289 nm). FEB calibration plots were linear between 0.1 and 7 μg mL -1 in both methods A and B. In method B, DIC showed linear response in the range of 0.08-8 μg mL -1 . Sample preparation was performed by liquid-liquid extraction using diethyl ether. Both methods did not record any interference from plasma matrix, the studied drugs' metabolites or their decomposition products. They were successfully applied for the determination of the studied drugs in healthy male volunteers after oral administration of FEB or FEB/DIC dosage forms. FEB plasma concentration increased significantly when given with DIC. The proposed methods provided very simple, rapid and cheap approaches that might be attractive for the future pharmacokinetic and bioavailability studies of FEB and/or DIC. Copyright © 2018 Elsevier B.V. All rights reserved.

The China-Africa Connection: Implications for United States Foreign Policy

DTIC Science & Technology

1992-06-01

a Independencia total de Angola(UNITA) UNITA Governo Revolucionhrio de Angola _.. ... no Exillo LGRAE) GRAE Mozambique Frente de Liberta;&o de ...Moqambique (FRELIMO) FRELIMO Comite Revolucionhrio de ,, Mocambigue (COREMO) COREMO Portuguese Partido Africano da Independencia Guinea da Guind e Cabo Verde...Postgraduate School Naval Postgraduate School NS _-. ’E_ ADURESSb (UIly, MStae, anda 2P c- de ) 71). ADDRESS (GiIy, SMate, and/-JP Code) Monterey, CA 93943

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orton, Frances; Ermler, Sibylle; Kugathas, Subramaniam

Many xenobiotics have been identified as in vitro androgen receptor (AR) antagonists, but information about their ability to produce combined effects at low concentrations is missing. Such data can reveal whether joint effects at the receptor are induced at low levels and may support the prioritisation of in vivo evaluations and provide orientations for the grouping of anti-androgens in cumulative risk assessment. Combinations of 30 AR antagonists from a wide range of sources and exposure routes (pesticides, antioxidants, parabens, UV-filters, synthetic musks, bisphenol-A, benzo(a)pyrene, perfluorooctane sulfonate and pentabromodiphenyl ether) were tested using a reporter gene assay (MDA-kb2). Chemicals were combinedmore » at three mixture ratios, equivalent to single components' effect concentrations that inhibit the action of dihydrotesterone by 1%, 10% or 20%. Concentration addition (CA) and independent action were used to calculate additivity expectations. We observed complete suppression of dihydrotestosterone effects when chemicals were combined at individual concentrations eliciting 1%, 10% or 20% AR antagonistic effect. Due to the large number of mixture components, the combined AR antagonistic effects occurred at very low concentrations of individual mixture components. CA slightly underestimated the combined effects at all mixture ratios. In conclusion, large numbers of AR antagonists from a wide variety of sources and exposure routes have the ability of acting together at the receptor to produce joint effects at very low concentrations. Significant mixture effects are observed when chemicals are combined at concentrations that individually do not induce observable AR antagonistic effects. Cumulative risk assessment for AR antagonists should apply grouping criteria based on effects where data are available, rather than on criteria of chemical similarity. - Highlights: • Mixtures of AR antagonists at low individual concentrations cause complete inhibition. • Concentration addition was an appropriate prediction model for observed effects. • Risk assessment for AR antagonists should use grouping criteria based on effects.« less

Mixture effects of 30 environmental contaminants on incident metabolic syndrome-A prospective study.

PubMed

Lind, Lars; Salihovic, Samira; Lampa, Erik; Lind, P Monica

2017-10-01

Several cross-sectional studies have linked different environmental contaminants to the metabolic syndrome (MetS). However, mixture effects have not been investigated and no prospective studies exist regarding environmental contaminants and the MetS. To study mixture effects of contaminants on the risk of incident MetS in a prospective fashion. Our sample consisted of 452 subjects from the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS) study (50% women, all aged 70years) free from the MetS at baseline, being followed for 10years. At baseline, 30 different environmental contaminants were measured; 6 polychlorinated biphenyls (PCBs), 3 organochlorine (OC) pesticides, one dioxin, one polybrominated diphenyl ether (all in plasma), 8 perfluoroalkyl substances (in plasma) and 11 metals (in whole blood). The MetS was defined by the ATPIII/NCEP criteria. Gradient boosted Classification and Regression Trees (CARTs) was used to evaluate potential synergistic and additive mixture effects on incident MetS. During 10-year follow-up, 92 incident cases of the MetS occurred. PCB126, PCB170, hexachlorobenzene (HCB) and PCB118 levels were all associated with incident MetS in an additive fashion (OR 1.73 for a change from 10th to 90th percentile (95%CI 1.24-3.04) for PCB126, OR 0.63 (0.42-0.78) for PCB170, OR 1.44 (1.09-2.20) for HCB and OR 1.46 (1.13-2.43) for PCB118). No synergistic effects were found. A mixture of environmental contaminants, with PCB126, PCB170, HCB and PCB118 being the most important, showed associations with future development of the MetS in an additive fashion in this prospective study. Thus, mixture effects of environmental contaminants could contribute to the development of cardio-metabolic derangements. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Catalytic oxidation of dimethyl ether

DOEpatents

Zelenay, Piotr; Wu, Gang; Johnston, Christina M.; Li, Qing

2016-05-10

A composition for oxidizing dimethyl ether includes an alloy supported on carbon, the alloy being of platinum, ruthenium, and palladium. A process for oxidizing dimethyl ether involves exposing dimethyl ether to a carbon-supported alloy of platinum, ruthenium, and palladium under conditions sufficient to electrochemically oxidize the dimethyl ether.

Palladium-Catalyzed Reductive Insertion of Alcohols into Aryl Ether Bonds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Meng; Gutiérrez, Oliver Y.; Camaioni, Donald M.

Pd/C catalyzes C-O bond cleavage of aryl ethers (diphenyl ether and cyclohexyl phenyl ether) by methanol in H2. The aromatic C-O bond is cleaved by reductive methanolysis, which is initiated by Pd-catalyzed partial hydrogenation of one phenyl ring to form an enol ether. The enol ether reacts rapidly with methanol to form a ketal, which generates methoxycyclohexene by eliminating phenol or an alkanol. Subsequent hydrogenation leads to methoxycyclohexane.

Feeding of by-products completely replaced cereals and pulses in dairy cows and enhanced edible feed conversion ratio.

PubMed

Ertl, P; Zebeli, Q; Zollitsch, W; Knaus, W

2015-02-01

When fed human-edible feeds, such as grains and pulses, dairy cows are very inefficient in transforming them into animal products. Therefore, strategies to reduce human-edible inputs in dairy cow feeding are needed to improve food efficiency. The aim of this feeding trial was to analyze the effect of the full substitution of a common concentrate mixture with a by-product concentrate mixture on milk production, feed intake, blood values, and the edible feed conversion ratio (eFCR), defined as human-edible output per human edible input. The experiment was conducted as a change-over design, with each experimental period lasting for 7wk. Thirteen multiparous and 5 primiparous Holstein cows were randomly assigned to 1 of 2 treatments. Treatments consisted of a grass silage-based forage diet supplemented with either conventional ingredients or solely by-products from the food processing industry (BP). The BP mixture had higher contents of fiber and ether extract, whereas starch content was reduced compared with the conventional mixture. Milk yield and milk solids were not affected by treatment. The eFCR in the BP group were about 4 and 2.7 times higher for energy and protein, respectively. Blood values did not indicate negative effects on cows' metabolic health status. Results of this feeding trial suggest that by-products could replace common concentrate supplements in dairy cow feeding, resulting in an increased eFCR for energy and protein which emphasizes the unique role of dairy cows as net food producers. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

RATE CONSTANTS FOR THE REACTIONS OF OH RADICALS AND CL ATOMS WITH DI-N-PROPYL ETHER AND DI-N-BUTYL ETHER AND THEIR DEUTERATED ANALOGS. (R825252)

EPA Science Inventory

Using relative rate methods, rate constants for the gas-phase reactions of OH radicals and Cl atoms with di-n-propyl ether, di-n-propyl ether-d₁₄, di-n-butyl ether and di-n-butyl ether-d₁₈ have been measured at 296 ? 2 K and atmos...

Peptide de novo sequencing of mixture tandem mass spectra.

PubMed

Gorshkov, Vladimir; Hotta, Stéphanie Yuki Kolbeck; Verano-Braga, Thiago; Kjeldsen, Frank

2016-09-01

The impact of mixture spectra deconvolution on the performance of four popular de novo sequencing programs was tested using artificially constructed mixture spectra as well as experimental proteomics data. Mixture fragmentation spectra are recognized as a limitation in proteomics because they decrease the identification performance using database search engines. De novo sequencing approaches are expected to be even more sensitive to the reduction in mass spectrum quality resulting from peptide precursor co-isolation and thus prone to false identifications. The deconvolution approach matched complementary b-, y-ions to each precursor peptide mass, which allowed the creation of virtual spectra containing sequence specific fragment ions of each co-isolated peptide. Deconvolution processing resulted in equally efficient identification rates but increased the absolute number of correctly sequenced peptides. The improvement was in the range of 20-35% additional peptide identifications for a HeLa lysate sample. Some correct sequences were identified only using unprocessed spectra; however, the number of these was lower than those where improvement was obtained by mass spectral deconvolution. Tight candidate peptide score distribution and high sensitivity to small changes in the mass spectrum introduced by the employed deconvolution method could explain some of the missing peptide identifications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study of Hyperbranched Poly(ethyleneimine) Polymers of Different Molecular Weight and Their Interaction with Epoxy Resin

PubMed Central

2018-01-01

Two different commercial hyperbranched poly(ethyleneimine)s (HBPEI), with molecular weights (MW) of 800 and 25,000 g/mol, and denoted as PEI800 and PEI25000, respectively, as well as the mixtures with a Diglycidyl Ether of Bisphenol-A (DGEBA) epoxy resin, have been studied using thermal analysis techniques (DSC, TGA), dielectric relaxation spectroscopy (DRS), and dynamic mechanical analysis (DMA). Only a single glass transition is observed in these mixtures by DSC. DRS of the HBPEIs shows three dipolar relaxations: γ, β, and α. The average activation energy for the γ-relaxation is similar for all HBPEIs and is associated with the motion of the terminal groups. The β-relaxation has the same average activation energy for both PEI800 and PEI25000; this relaxation is attributed to the mobility of the branches. The α-relaxation peak for all the HBPEIs is an asymmetric peak with a shoulder on the high temperature side. This shoulder suggests the existence of ionic charge trapped in the PEI. For the mixtures, the γ- and β-relaxations follow the behaviour of the epoxy resin alone, indicating that the epoxy resin dominates the molecular mobility. The α-relaxation by DRS is observed only as a shoulder, as a consequence of an overlap with conductivity effects, whereas by DMA, it is a clear peak. PMID:29522480

Molecular Simulation of the Vapor-Liquid Phase Behavior of Lennard-Jones Mixtures in Porous Solids

DTIC Science & Technology

2006-09-01

sur la Catalyse, Centre National de la Recherche Scientifique, Group de Chimie Theorique, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex, France...and Group de Chimie Theorique, Ecole Normale Superieure de Lyon, 46 Allee d’Italie, 69364 Lyon, Cedex 07, France 14. ABSTRACT We present vapor...Scientifique, Group de Chimie Theorique, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex, France and Group de Chimie Theorique, Ecole Normale

HPLC-Based Mass Spectrometry Characterizes the Phospholipid Alterations in Ether-Linked Lipid Deficiency Models Following Oxidative Stress

PubMed Central

Drechsler, Robin; Chen, Shaw-Wen; Dancy, Blair C. R.; Mehrabkhani, Lena

2016-01-01

Despite the fact that the discovery of ether-linked phospholipids occurred nearly a century ago, many unanswered questions remain concerning these unique lipids. Here, we characterize the ether-linked lipids of the nematode with HPLC-MS/MS and find that more than half of the phosphoethanolamine-containing lipids are ether-linked, a distribution similar to that found in mammalian membranes. To explore the biological role of ether lipids in vivo, we target fatty acyl-CoA reductase (fard-1), an essential enzyme in ether lipid synthesis, with two distinct RNAi strategies. First, when fard-1 RNAi is initiated at the start of development, the treated animals have severely reduced ether lipid abundance, resulting in a shift in the phosphatidylethanolamine lipid population to include more saturated fatty acid chains. Thus, the absence of ether lipids during development drives a significant remodeling of the membrane landscape. A later initiation of fard-1 RNAi in adulthood results in a dramatic reduction of new ether lipid synthesis as quantified with 15N-tracers; however, there is only a slight decrease in total ether lipid abundance with this adult-only fard-1 RNAi. The two RNAi strategies permit the examination of synthesis and ether lipid abundance to reveal a relationship between the amount of ether lipids and stress survival. We tested whether these species function as sacrificial antioxidants by directly examining the phospholipid population with HPLC-MS/MS after oxidative stress treatment. While there are significant changes in other phospholipids, including polyunsaturated fatty acid-containing species, we did not find any change in ether-linked lipids, suggesting that the role of ether lipids in stress resistance is not through their general consumption as free radical sinks. Our work shows that the nematode will be a useful model for future interrogation of ether lipid biosynthesis and the characterization of phospholipid changes in various stress conditions. PMID:27893806

Radionuclide-binding compound, a radionuclide delivery system, a method of making a radium complexing compound, a method of extracting a radionuclide, and a method of delivering a radionuclide

DOEpatents

Fisher, Darrell R.; Wai, Chien M.; Chen, Xiaoyuan

2000-01-01

The invention pertains to compounds which specifically bind radionuclides, and to methods of making radionuclide complexing compounds. In one aspect, the invention includes a radionuclide delivery system comprising: a) a calix[n]arene-crown-[m]-ether compound, wherein n is an integer greater than 3, and wherein m is an integer greater than 3, the calix[n]arene-crown-[m]-ether compound comprising at least two ionizable groups; and b) an antibody attached to the calix[n]arene-crown-[m]-ether compound. In another aspect, the invention includes a method of making a radium complexing compound, comprising: a) providing a calix[n]arene compound, wherein n is an integer greater than 3, the calix[n]arene compound comprising n phenolic hydroxyl groups; b) providing a crown ether precursor, the crown ether precursor comprising a pair of tosylated ends; c) reacting the pair of tosylated ends with a pair of the phenolic hydroxyl groups to convert said pair of phenolic hydroxyl groups to ether linkages, the ether linkages connecting the crown ether precursor to the calix[n]arene to form a calix[n]arene-crown-[m]-ether compound, wherein m is an integer greater than 3; d) converting remaining phenolic hydroxyl groups to esters; e) converting the esters to acids, the acids being proximate a crown-[m]-ether portion of the calix[n]arene-crown-[m]-ether compound; and f) providing a Ra.sup.2+ ion within the crown-[m]-ether portion of the calix[n]arene-crown-[m]-ether compound.

Etude du strabisme chez des enfants de 0 à 15 ans suivis a Lubumbashi, République Démocratique du Congo: analyse des aspects épidémiologiques et cliniques

PubMed Central

Bienvenu, Yogolelo Asani; Angel, Musau Nkola; Sebastien, Mbuyi Musanzayi; Philippe, Cilundika Mulenga; Léon, Kabamba Ngombe; Eugene, Twite Kabange; Chami, Cham Lubamba; Prosper, Kalenga Muenze Kayamba; Claude, Speeg-Schatz; Gaby, Chenge Borasisi

2015-01-01

Introduction Le strabisme est défini comme un syndrome à double composante: motrice et sensorielle. Le but de ce travail est de décrire les aspects épidémiologiques et cliniques du strabisme chez l'enfant congolais de 0 à 15 ans dans la ville de Lubumbashi. Méthodes Il s'agit d'une étude descriptive longitudinale sur les aspects épidémiologiques et cliniques du strabisme chez l'enfant congolais de 0 à 15 ans dans la ville de Lubumbashi entre Décembre 2012 à Décembre 2013. Nous avons recueilli l’âge des patients, leur sexe, leur provenance, le type de strabisme, la réfraction, le fond d'oeil, les antécédents (hérédité) ainsi que le type de la déviation strabique observé sur 70 patients. Résultats Nous avons observé 70 cas de strabisme manifeste dont 31 cas (44,28%) étaient dans la tranche d’âge comprise entre 0 et 5 ans. L’âge moyen de nos patients était de 6,7 ans avec une prédominance du sexe féminin, soit 51,42%. Le strabisme était convergent dans 65,71%, divergent dans 30%, et vertical dans 4,28%. Les ésotropies représentaient 65 cas (92,85%), quatre cas (5,71%) avaient un antécédent familial de strabisme au premier degré de parenté, 21 cas (30%) au second degré de parenté, 45 cas (64,28%) n'avaient pas cet antécédent. L'oeil gauche était le plus dominé dans 30% des cas. Les facteurs favorisant le strabisme étaient inconnus dans 54 cas (77,14%). Le strabisme était secondaire à l'hypermétropie chez 32 patients (42,71%). Conclusion La fréquence du strabisme dans la ville de Lubumbashi chez les enfants âgés de 0 à 15 ans est de 0,50%. Comme dans la plupart des études sur le strabisme de l'enfant, c'est l’ésotropie qui est la déviation la plus commune. PMID:26834919

Vapor intrusion risk of fuel ether oxygenates methyl tert-butyl ether (MTBE), tert-amyl methyl ether (TAME) and ethyl tert-butyl ether (ETBE): A modeling study.

PubMed

Ma, Jie; Xiong, Desen; Li, Haiyan; Ding, Yi; Xia, Xiangcheng; Yang, Yongqi

2017-06-15

Vapor intrusion of synthetic fuel additives represents a critical yet still neglected problem at sites contaminated by petroleum fuel releases. This study used an advanced numerical model to investigate the vapor intrusion potential of fuel ether oxygenates methyl tert-butyl ether (MTBE), tert-amyl methyl ether (TAME), and ethyl tert-butyl ether (ETBE). Simulated indoor air concentration of these compounds can exceed USEPA indoor air screening level for MTBE (110μg/m 3 ). Our results also reveal that MTBE has much higher chance to cause vapor intrusion problems than TAME and ETBE. This study supports the statements made by USEPA in the Petroleum Vapor Intrusion (PVI) Guidance that the vertical screening criteria for petroleum hydrocarbons may not provide sufficient protectiveness for fuel additives, and ether oxygenates in particular. In addition to adverse impacts on human health, ether oxygenate vapor intrusion may also cause aesthetic problems (i.e., odour and flavour). Overall, this study points out that ether oxygenates can cause vapor intrusion problems. We recommend that USEPA consider including the field measurement data of synthetic fuel additives in the existing PVI database and possibly revising the PVI Guidance as necessary. Copyright © 2017 Elsevier B.V. All rights reserved.

Equation of state of mixtures: density functional theory (DFT) simulations and experiments on Sandia's Z machine

NASA Astrophysics Data System (ADS)

Magyar, R. J.; Root, S.; Haill, T. A.; Schroen, D. G.; Mattsson, T. R.; Flicker, D. G.; Sandia National Laboratories Collaboration

2011-06-01

Mixtures of materials are expected to behave quite differently from their isolated constituents, particularly when the constituents atomic numbers differ significantly. To investigate the mixture behavior, we performed density functional theory (DFT) calculations on xenon/hydrogen, xenon/ethane, and platinum/hydrocarbon mixtures. In addition, we performed shock compression experiments on platinum-doped hydrocarbon foams up to 480 GPa using the Sandia Z-accelerator. Since the DFT simulations treat electrons and nuclei generically, simulations of pure and mix systems are expected to be of comparable accuracy. The DFT and experimental results are compared to hydrodynamic simulations using different mixing models in the equation of state. The role of de-mixing and the relative contributions of the enthalpy of mixing are explored. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of the Lockheed Martin company, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Boundary lubrication, thermal and oxidative stability of a fluorinated polyether and a perfluoropolyether triazine

NASA Technical Reports Server (NTRS)

Jones, W. R., Jr.; Snyder, C. E., Jr.

1979-01-01

Boundary lubricating characteristics, thermal stability, and oxidation-corrosion stability were determined for a fluorinated polyether and a perfluoropolyether triazine. A ball-on-disk apparatus, a tensimeter, and oxidation-corrosion apparatus were used. Results were compared to data for a polyphenyl ether and a C-ether. The polyether and triazine yielded better boundary lubricating characteristics than either the polyphenyl ether or C-ether. The polyphenyl ether had the greatest thermal stability (443 C) while the other fluids had stabilities in the range 389 to 397 C. Oxidation-corrosion results indicated the following order of stabilities: perfluoropolyether trizine greater than polyphenyl ether greater than C-ether greater than fluorinated polyether.

Sinterable Ceramic Powders from Laser-Heated Gases.

DTIC Science & Technology

1988-02-01

ether . carboxylic acid. and aldehyde clases: water is also included.Acrigto William and Goodman.’ a single crystalline sili- The single-crstalline...represent commonly available organic families, Including aliphatic and aromatic hydrocarbons, chlorides, ethers , ketones , esters, alcohols, aldehydes...Hydrocarbons Ketone Amine Chlorides Low-alcohols 8f . Ether Ester - _Aldehyde Ether Ketones High-alcohols 04 Carboxylic Ester I acid Ether o . Nitrile

Identification of the flame retardant decabromodiphenyl ethane in the environment.

PubMed

Kierkegaard, Amelie; Björklund, Jonas; Fridén, Ulrika

2004-06-15

The brominated flame retardant decabromodiphenyl ethane, DeBDethane, is marketed as an alternative to decabromodiphenyl ether, BDE209. There are currently no data available about the presence of DeBDethane in the environment. In this study, DeBDethane was positively identified by high-resolution mass spectrometry and quantified by low-resolution mass spectrometry with electron capture negative ionization in sewage sludge, sediment, and indoor air. It was found in 25 of the 50 Swedish sewage treatment plants investigated, with estimated levels up to about 100 ng/g dry weight. The concentration of DeBDethane in sediment from Western Scheldt in The Netherlands was 24 ng/g dry weight, and in an air sample from a Swedish electronics dismantling facility it was 0.6 ng/m3. DeBDethane was also found together with nonabromodiphenyl ethanes in water piping insulation. All samples contained BDE209 in higher concentrations as compared to DeBDethane (DeBDethane/BDE209 ratios ranging from 0.02 to 0.7), probably reflecting the higher and longer usage of BDE209. There is an ongoing risk assessment within the European Union regarding BDE209. Since DeBDethane has similar applications, it is important to investigate its environmental behavior before using it to replace BDE209.

40 CFR 372.38 - Exemptions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... person produced the mixture, either by mixing the chemicals involved or by causing a chemical reaction... COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.38 Exemptions. (a) De minimis concentrations of a toxic chemical in a mixture. If a toxic...

40 CFR 372.38 - Exemptions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... person produced the mixture, either by mixing the chemicals involved or by causing a chemical reaction... COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.38 Exemptions. (a) De minimis concentrations of a toxic chemical in a mixture. If a toxic...

40 CFR 372.38 - Exemptions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... person produced the mixture, either by mixing the chemicals involved or by causing a chemical reaction... COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.38 Exemptions. (a) De minimis concentrations of a toxic chemical in a mixture. If a toxic...

40 CFR 372.38 - Exemptions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... person produced the mixture, either by mixing the chemicals involved or by causing a chemical reaction... COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.38 Exemptions. (a) De minimis concentrations of a toxic chemical in a mixture. If a toxic...

40 CFR 372.38 - Exemptions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... person produced the mixture, either by mixing the chemicals involved or by causing a chemical reaction... COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.38 Exemptions. (a) De minimis concentrations of a toxic chemical in a mixture. If a toxic...

Physiological effects of brominated flame retardants on NC/Nga mice.

PubMed

Tanaka, Michitaka; Inoue, Ken-Ichiro; Shimada, Akinori; Takano, Hirohisa

2018-02-01

Brominated flame retardants (BFRs) are used as an additive or reactive components in various materials. Regarding their health concerns, their immunotoxicity have not been clarified yet. In the current study, we examined the effects of systemic exposure to two types of BFRs, DE71 and DE79, on pathophysiologic traits of murine atopic dermatitis (AD). Male NC/Nga mice were repeatedly injected intraperitoneally with DE71 and DE79 and/or mite allergen (Dermatophagoides pteronyssinus: Dp) into their right ears. Thereafter, clinical scores, macroscopic findings of inflammatory foci, and Ig values in serum were examined. Both DEs significantly aggravated clinical scores induced by mite allergen including skin dryness and edema. Total IgE titer was significantly greater in the Dp + DE79 group than in the Dp group. Taken together, exposure to BFRs can exacerbate AD-like skin lesions related to mite allergen in mice. The accentuating effects may be mediated, at least in part, through hyperproduction of IgE.

Biodegradation of bis(1-chloro-2-propyl) ether via initial ether scission and subsequent dehalogenation by Rhodococcus sp. strain DTB.

PubMed

Moreno Horn, Marcus; Garbe, Leif-Alexander; Tressl, Roland; Adrian, Lorenz; Görisch, Helmut

2003-04-01

Rhodococcus sp. strain DTB (DSM 44534) grows on bis(1-chloro-2-propyl) ether (DDE) as sole source of carbon and energy. The non-chlorinated diisopropyl ether and bis(1-hydroxy-2-propyl) ether, however, did not serve as substrates. In ether degradation experiments with dense cell suspensions, 1-chloro-2-propanol and chloroacetone were formed, which indicated that scission of the ether bond is the first step while dehalogenation of the chlorinated C(3)-compounds occurs at a later stage of the degradation pathway. Inhibition of ether scission by methimazole suggested that the first step in degradation is catalyzed by a flavin-dependent enzyme activity. The non-chlorinated compounds 1,2-propanediol, hydroxyacetone, lactate, pyruvate, 1-propanol, propanal, and propionate also supported growth, which suggested that the intermediates 1,2-propanediol and hydroxyacetone are converted to pyruvate or to propionate, which can be channeled into the citric acid cycle by a number of routes. Total release of chloride and growth-yield experiments with DDE and non-chlorinated C(3)-compounds suggested complete biodegradation of the chlorinated ether.

Some actions of substituted choline phenyl ethers, particularly of choline 2:6-xylyl ether

PubMed Central

Edge, N. D.; Mason, D. F. J.; Wyllie, J. H.

1957-01-01

Marked nicotine-like stimulant properties are possessed by choline phenyl ether and choline o-tolyl ether, and to a decreasing extent by choline 2:6-xylyl ether and choline 2:4:6-mesityl ether. The compounds all show neuromuscular blocking properties, which are of short duration and pass from mainly decamethonium-like to mainly curare-like as more methyl groups are added to the phenyl nucleus. This series of compounds also possesses muscarinic, weak anti-adrenaline and vasodilator properties, as well as long-lasting local anaesthetic effects in the two compounds tested by intradermal injection. PMID:13460236

Controlled human exposures to diesel exhaust

EPA Science Inventory

Diesel exhaust (DE) is a complex mixture of gaseous and particulate compounds resulting from an incomplete combustion of diesel fuel. Controlled human exposures to DE and diesel exhaust particles (DEP) have contributed to understanding health effects. Such exposure studies of h...

CH3OCH3 in Orion-KL: a striking similarity with HCOOCH3

NASA Astrophysics Data System (ADS)

Brouillet, N.; Despois, D.; Baudry, A.; Peng, T.-C.; Favre, C.; Wootten, A.; Remijan, A. J.; Wilson, T. L.; Combes, F.; Wlodarczak, G.

2013-02-01

Context. Orion-KL is a remarkable, nearby star-forming region where a recent explosive event has generated shocks that could have released complex molecules from the grain mantles. Aims: A comparison of the distribution of the different complex molecules will help in understanding their formation and constraining the chemical models. Methods: We used several data sets from the Plateau de Bure Interferometer to map the dimethyl ether emission with different arcsec spatial resolutions and different energy levels (from Eup = 18 to 330 K) to compare with our previous methyl formate maps. Results: Our data show remarkable similarity between the dimethyl ether (CH3OCH3) and the methyl formate (HCOOCH3) distributions even on a small scale (1.8″ × 0.8″ or ~500 AU). This long suspected similarity, seen from both observational and theoretical arguments, is demonstrated with unprecedented confidence, with a correlation coefficient of maps ~0.8. Conclusions: A common precursor is the simplest explanation of our correlation. Comparisons with previous laboratory work and chemical models suggest the major role of grain surface chemistry and a recent release, probably with little processing, of mantle molecules by shocks. In this case the CH3O radical produced from methanol ice would be the common precursor (whereas ethanol, C2H5OH, is produced from the radical CH2OH). The alternative gas phase scheme, where protonated methanol CH3OH+2 is the common precursor to produce methyl formate and dimethyl ether through reactions with HCOOH and CH3OH, is also compatible with our data. Our observations cannot yet definitely allow a choice between the different chemical processes, but the tight correlation between the distributions of HCOOCH3 and CH3OCH3 strongly contrasts with the different behavior we observe for the distributions of ethanol and formic acid. This provides a very significant constraint on models. Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).

Negative Cognitive Style Trajectories in the Transition to Adolescence

ERIC Educational Resources Information Center

Mezulis, Amy; Funasaki, Kristyn; Hyde, Janet Shibley

2011-01-01

The development of negative cognitive style was examined in a longitudinal study of 366 community youth. Cognitive style and depressive symptoms were evaluated at ages 11, 13, and 15. Latent growth mixture modeling identified three unique trajectory patterns of negative cognitive style. The "normative" group (71% of the sample) displayed the least…

76 FR 45333 - Office of Hazardous Materials Safety; Notice of Application for Special Permits

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-28

... CFR 178.71....... To authorize the transportation in commerce of certain UN cylinders which have been... Specification 107A cylinders for use in transporting liquified or nonliquefied compressed gases, or mixtures... 173302a(a)(1), and specification 173.304a(a)(1). highpressure longitudinal welded and drawn cylinder for...

Methyl tert-butyl ether (MTBE) in public and private wells in New Hampshire: Occurrence, factors, and possible implications

USGS Publications Warehouse

Ayotte, J.D.; Argue, D.M.; McGarry, F.J.; Degnan, J.R.; Hayes, L.; Flanagan, S.M.; Helsel, D.R.

2008-01-01

Methyl tert-butyl ether (MTBE) concentrations ???0.2 ??g/L were found in samples of untreated water in 18% of public-supply wells (n = 284) and 9.1% of private domestic wells (n = 264) sampled in 2005 and 2006 in New Hampshire. In counties that used reformulated gasoline (RFG), MTBE occurred at or above 0.2 ??g/L in 30% of public- and 17% of private-supply wells. Additionally, 52% of public-supply wells collocated with fuel storage and 71% of mobile home park wells had MTBE. MTBE occurrence in public-supply wells was predicted by factors such as proximity to sources of fuel, land use, and population density, as well as low pH and distance from mapped lineaments. RFG use, land-use variables, and pH were important predictors of private-well MTBE occurrence. Variables representing sources of MTBE, such as the distance to known fuel sources, were not significant predictors of MTBE occurrence in private-supply wells. It is hypothesized that private wells may become contaminated from the collective effects of sources in high population areas and from undocumented incidental releases from onsite or proximal gasoline use. From 2003 to 2005, MTBE occurrence decreased in 63 public-supply wells and increased in 60 private-supply wells, but neither trend was statistically significant. ?? 2008 American Chemical Society.

Effects of aging on serum levels of lipid molecular species as determined by lipidomics analysis in Japanese men and women.

PubMed

Kawanishi, Noriaki; Kato, Yuki; Yokozeki, Kyosuke; Sawada, Shuji; Sakurai, Ryota; Fujiwara, Yoshinori; Shinkai, Shoji; Goda, Nobuhito; Suzuki, Katsuhiko

2018-06-06

Aging is known to be associated with increased risk of lipid disorders related to the development of type 2 diabetes. Recent evidence revealed that change of lipid molecule species in blood is associated with the risk of type 2 diabetes. However, changes in lipid molecular species induced by aging are still unknown. We assessed the effects of age on the serum levels of lipid molecular species as determined by lipidomics analysis. Serum samples were collected from ten elderly men (71.7 ± 0.5 years old) and women (70.2 ± 1.0 years old), ten young men (23.9 ± 0.4 years old), and women (23.9 ± 0.7 years old). Serum levels of lipid molecular species were determined by liquid chromatography mass spectrometry-based lipidomics analysis. Our mass spectrometry analysis revealed increases in the levels of multiple triacylglycerol molecular species in the serum of elderly men and women. Moreover, serum levels of total ester-linked phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were increased by aging. In contrast, serum levels of specific ether-linked PC and PE molecular species were lower in elderly individuals than in young individuals. Our finding indicates that specific lipid molecular species, such as ether- and ester- linked phospholipids, may be selectively altered by aging.

Development and validation of a multi-residue method for the analysis of brominated and organophosphate flame retardants in indoor dust.

PubMed

He, Chang; Wang, Xianyu; Thai, Phong; Mueller, Jochen F; Gallen, Christie; Li, Yan; Baduel, Christine

2017-03-01

Flame retardants are associated to numerous adverse health effects, can accumulate in humans and have been used intensively worldwide. Recently, dust has been identified as a major human exposure route for flame retardants. The aim of this study was to develop a multi-residue method using a two-step SPE purification. It enabled us to effectively limit co-extracted matrix/interferets and therefore a simultaneous analysis of brominated and organophosphate flame retardants for indoor dust was achieved. The optimized method was validated according to standard protocol and achieved good accuracy and reproducibility (percent error ranged from -29% to 28%). Standard Reference Material (SRM) for dust was also analysed, and good agreement was found with reported brominated and organophosphate flame retardants (OPFRs) concentrations. The applicability of the validated method was demonstrated by the analysis of ten indoor dust samples from ten Australian homes. Overall 89% of the analytes were detected in these samples. The average concentrations of ∑OPFRs and ∑PBDEs in those samples were 41 and 3.6μg/g, respectively. Tris(2-butoxyethyl) phosphate and tris(2-chloroisopropyl) phosphate were the most abundant OPFRs, accounting for 57-92% ∑OPFRs, while decabromodiphenyl ether dominated the Polybrominated diphenyl ethers (PBDE) congeners contributing between 71-94% to the ∑PBDEs. Copyright © 2016 Elsevier B.V. All rights reserved.

Para rubber seed oil: new promising unconventional oil for cosmetics.

PubMed

Lourith, Nattaya; Kanlayavattanakul, Mayuree; Sucontphunt, Apirada; Ondee, Thunnicha

2014-01-01

Para rubber seed was macerated in petroleum ether and n-hexane, individually, for 30 min. The extraction was additionally performed by reflux and soxhlet for 6 h with the same solvent and proportion. Soxhlet extraction by petroleum ether afforded the greatest extractive yield (22.90 ± 0.92%). Although antioxidant activity by means of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay was insignificantly differed in soxhleted (8.90 ± 1.15%) and refluxed (9.02 ± 0.71%) by n-hexane, soxhlet extraction by n-hexane was significantly (p < 0.05) potent scavenged 2,2'-azino-bis(3-ethylbenzothaiazoline)-6-sulfonic acid) or ABTS radical with trolox equivalent antioxidant capacity (TEAC) of 66.54 ± 6.88 mg/100 g oil. This extract was non cytotoxic towards normal human fibroblast cells. In addition, oleic acid and palmitic acid were determined at a greater content than in the seed of para rubber cultivated in Malaysia, although linoleic and stearic acid contents were not differed. This bright yellow extract was further evaluated on other physicochemical characters. The determined specific gravity, refractive index, iodine value, peroxide value and saponification value were in the range of commercialized vegetable oils used as cosmetic raw material. Therefore, Para rubber seed oil is highlighted as the promising ecological ingredient appraisal for cosmetics. Transforming of the seed that is by-product of the important industrial crop of Thailand into cosmetics is encouraged accordingly.

Species and gender differences in the metabolism and distribution of tertiary amyl methyl ether in male and female rats and mice after inhalation exposure or gavage administration.

PubMed

Sumner, Susan C J; Janszen, Derek B; Asgharian, Bahman; Moore, Timothy A; Parkinson, Horace D; Fennell, Timothy R

2003-01-01

Tertiary amyl methyl ether (TAME) is a gasoline fuel additive used to reduce emissions. Understanding the metabolism and distribution of TAME is needed to assess potential human health issues. The effect of dose level, duration of exposure and route of administration on the metabolism and distribution of TAME were investigated in male and female F344 rats and CD-1 mice following inhalation or gavage administration. By 48 h after exposure, >96% of the administered radioactivity was expired in air (16-71%) or eliminated in urine and feces (28-72%). Following inhalation exposure, mice had a two- to threefold greater relative uptake of [14C]TAME compared with rats. Metabolites were excreted in urine of rats and mice that are formed by glucuronide conjugation of tertiary amyl alcohol (TAA), oxidation of TAA to 2,3-dihydroxy-2-methylbutane and glucuronide conjugation of 2,3-dihydroxy-2-methylbutane. A saturation in the uptake and metabolism of TAME with increased exposure concentration was indicated by a decreased relative uptake of total [14C]TAME equivalents and an increase in the percentage expired as volatiles. A saturation of P-450 oxidation of TAA was indicated by a disproportional decrease of 2,3-dihydroxy-2-methylbutane and its glucuronide conjugate with increased exposure concentration. Copyright 2003 John Wiley & Sons, Ltd.

Spatial trends of organochlorinated pesticides, polychlorinated biphenyls, and polybrominated diphenyl ethers in Atlantic Anguillid eels.

PubMed

Byer, Jonathan D; Lebeuf, Michel; Alaee, Mehran; Stephen, Brown R; Trottier, Steve; Backus, Sean; Keir, Michael; Couillard, Catherine M; Casselman, John; Hodson, Peter V

2013-02-01

The bioaccumulation of lipophilic contaminants such as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs) can result in a reduction in fitness and spawner quality in eels and may be a factor in Anguillid sp. population declines. Contaminant concentrations in eels have been studied extensively in Europe, but data for American eels are severely lacking. Concentrations of PCBs, OCPs, and PBDEs were determined in American eel from eastern Canada and New York, USA, along with European eel from Belgium. Principal component analysis revealed that eels captured in the St. Lawrence estuary were a mixture of upstream migrants from the St. Lawrence River watershed, and fish captured in local tributaries. Contaminant concentrations were dependent on origin, related to the local environment, and were lower than historic values. In Canada, concentrations of OCPs and PCBs in eel tissues were below the Canadian human consumption guidelines for contaminants in fish, indicating that the current risk to consumers is low. However, concentrations of PCBs, total DDT, and mirex in eels from L. Ontario and the upper St. Lawrence R. were above Great Lakes guidelines for the protection of piscivorous predators. Concentrations of penta-BDE homologs exceeded the Canadian guideline for environmental quality in over half of the eels in this study, but concentrations of the other homolog groups were below the guideline. Copyright © 2012 Elsevier Ltd. All rights reserved.

Comparative transcriptome analysis of Methylibium petroleiphilum PM1 exposed to the fuel oxygenates methyl tert-butyl ether and ethanol.

PubMed

Hristova, Krassimira R; Schmidt, Radomir; Chakicherla, Anu Y; Legler, Tina C; Wu, Janice; Chain, Patrick S; Scow, Kate M; Kane, Staci R

2007-11-01

High-density whole-genome cDNA microarrays were used to investigate substrate-dependent gene expression of Methylibium petroleiphilum PM1, one of the best-characterized aerobic methyl tert-butyl ether (MTBE)-degrading bacteria. Differential gene expression profiling was conducted with PM1 grown on MTBE and ethanol as sole carbon sources. Based on microarray high scores and protein similarity analysis, an MTBE regulon located on the megaplasmid was identified for further investigation. Putative functions for enzymes encoded in this regulon are described with relevance to the predicted MTBE degradation pathway. A new unique dioxygenase enzyme system that carries out the hydroxylation of tert-butyl alcohol to 2-methyl-2-hydroxy-1-propanol in M. petroleiphilum PM1 was discovered. Hypotheses regarding the acquisition and evolution of MTBE genes as well as the involvement of IS elements in these complex processes were formulated. The pathways for toluene, phenol, and alkane oxidation via toluene monooxygenase, phenol hydroxylase, and propane monooxygenase, respectively, were upregulated in MTBE-grown cells compared to ethanol-grown cells. Four out of nine putative cyclohexanone monooxygenases were also upregulated in MTBE-grown cells. The expression data allowed prediction of several hitherto-unknown enzymes of the upper MTBE degradation pathway in M. petroleiphilum PM1 and aided our understanding of the regulation of metabolic processes that may occur in response to pollutant mixtures and perturbations in the environment.

Brominated flame retardants (BFRs) in breast milk and associated health risks to nursing infants in Northern Tanzania.

PubMed

Müller, M H B; Polder, A; Brynildsrud, O B; Lie, E; Løken, K B; Manyilizu, W B; Mdegela, R H; Mokiti, F; Murtadha, M; Nonga, H E; Skaare, J U; Lyche, J L

2016-01-01

The main aim of this study was to assess brominated flame retardants (BFRs) in breast milk in the Northern parts of Tanzania. Ninety-five colostrum samples from healthy, primiparous mothers at Mount Meru Regional Referral Hospital (MMRRH), Arusha Tanzania, were analyzed for polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB), (2,3-dibromopropyl) (2,4,6-tribromophenyl) ether (DPTE), pentabromoethylbenzene (PBEB) and 2,3,4,5,6-pentabromotoluene (PBT). The Ʃ7PBDE (BDE 28, 47, 99, 100, 153, 154, 183) ranged from below level of detection (

Multiyear Measurements of Flame Retardants and Organochlorine Pesticides in Air in Canada's Western Sub-Arctic.

PubMed

Yu, Yong; Hung, Hayley; Alexandrou, Nick; Roach, Pat; Nordin, Ken

2015-07-21

Fourteen polybrominated diphenyl ethers (PBDEs), 14 non-BDE flame retardants (FRs), and 25 organochlorine pesticides (OCPs) were analyzed in air samples collected at Little Fox Lake (LFL) in Canada's Yukon Territory from August 2011 to December 2014. LFL is a long-term monitoring station operated under the Northern Contaminants Program (NCP) and one of only a few stations that contribute to the assessment of air pollution levels and pathways to the sub-Arctic region. BDE-47 was the most abundant congener among the 14 PBDEs, followed by BDE-99. Non-BDE FRs pentabromotoluene (PBT) and dechlorane plus (DP) were detected in all the samples. Dechlorane 602, 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE), hexabromobenzene (HBB), and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB) were also detected in >75% of all samples. PBDEs have shown a decreasing tendency as of 2013, which may reflect the phase-out of penta- and octa-BDE mixtures has led to significant decline in the atmosphere. The highest concentrations of OCPs were observed for hexachlorobenzene (HCB), with a median concentration of 61 pg/m(3), followed by α-hexachlorocyclohexane (α-HCH) and α-endosulfan. Potential source contribution function (PSCF) highlights Northern Canada, Pacific, and East Asia as potential sources in warm seasons; whereas in cold seasons, the chemicals mainly came from the Pacific Rim.

In vitro cytotoxicity assessment of a West Virginia chemical spill mixture involving 4-methylcyclohexanemethanol and propylene glycol phenyl ether.

PubMed

Han, Alice A; Fabyanic, Emily B; Miller, Julie V; Prediger, Maren S; Prince, Nicole; Mouch, Julia A; Boyd, Jonathan

2017-04-01

Thousands of gallons of industrial chemicals, crude 4-methylcyclohexanemethanol (MCHM) and propylene glycol phenyl ether (PPh), leaked from industrial tanks into the Elk River in Charleston, West Virginia, USA, on January 9, 2014. A considerable number of people were reported to exhibit symptoms of chemical exposure and an estimated 300,000 residents were advised not to use or drink tap water. At the time of the spill, the existing toxicological data of the chemicals were limited for a full evaluation of the health risks, resulting in concern among those in the impacted regions. In this preliminary study, we assessed cell viability and plasma membrane degradation following a 24-h exposure to varying concentrations (0-1000 μM) of the two compounds, alone and in combination. Evaluation of different cell lines, HEK-293 (kidney), HepG2 (liver), H9c2 (heart), and GT1-7 (brain), provided insight regarding altered cellular responses in varying organ systems. Single exposure to MCHM or PPh did not affect cell viability, except at doses much higher than the estimated exposure levels. Certain co-exposures significantly reduced metabolic activity and increased plasma membrane degradation in GT1-7, HepG2, and H9c2 cells. These findings highlight the importance of examining co-exposures to fully understand the potential toxic effects.

Polybrominated diphenyl ethers: occurrence, dietary exposure, and toxicology.

PubMed Central

Darnerud, P O; Eriksen, G S; Jóhannesson, T; Larsen, P B; Viluksela, M

2001-01-01

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in plastics (concentration, 5--30%) and in textile coatings. Commercial products consist predominantly of penta-, octa-, and decabromodiphenyl ether mixtures, and global PBDE production is about 40,000 tons per year. PBDEs are bioaccumulated and biomagnified in the environment, and comparatively high levels are often found in aquatic biotopes from different parts of the world. During the mid-1970--1980s there was a substantial increase in the PBDE levels with time in both sediments and aquatic biota, whereas the latest Swedish data (pike and guillemot egg) may indicate that levels are at steady state or are decreasing. However, exponentially increasing PBDE levels have been observed in mother's milk during 1972--1997. Based on levels in food from 1999, the dietary intake of PBDE in Sweden has been estimated to be 0.05 microg per day. Characteristic end points of animal toxicity are hepatotoxicity, embryotoxicity, and thyroid effects as well as maternal toxicity during gestation. Recently, behavioral effects have been observed in mice on administration of PBDEs during a critical period after birth. Based on the critical effects reported in available studies, we consider the lowest-observed-adverse-effect level (LOAEL) value of the PBDE group to be 1 mg/kg/day (primarily based on effects of pentaBDEs). In conclusion, with the scientific knowledge of today and based on Nordic intake data, the possible consumer health risk from PBDEs appears limited, as a factor of over 10(6) separates the estimated present mean dietary intake from the suggested LOAEL value. However, the presence of many and important data gaps, including those in carcinogenicity, reproduction, and developmental toxicity, as well as additional routes of exposure, make this conclusion only preliminary. Moreover, the time trend of PBDEs in human breast milk is alarming for the future. PMID:11250805

Stereocontrolled Cyanohydrin Ether Synthesis through Chiral Brønsted Acid-Mediated Vinyl Ether Hydrocyanation

PubMed Central

Lu, Chunliang; Su, Xiaoge; Floreancig, Paul E.

2013-01-01

Vinyl ethers can be protonated to generate oxocarbenium ions that react with Me3SiCN to form cyanohydrin alkyl ethers. Reactions that form racemic products proceed efficiently upon converting the vinyl ether to an α-chloro ether prior to cyanide addition in a pathway that proceeds through Brønsted acid-mediated chloride ionization. Enantiomerically enriched products can be accessed by directly protonating the vinyl ether with a chiral Brønsted acid to form a chiral ion pair. Me3SiCN acts as the nucleophile and PhOH serves as a stoichiometric proton source in a rare example of an asymmetric bimolecular nucleophilic addition reaction into an oxocarbenium ion. Computational studies provide a model for the interaction between the catalyst and the oxocarbenium ion. PMID:23968162

Thermodynamic equilibrium calculations of dimethyl ether steam reforming and dimethyl ether hydrolysis

NASA Astrophysics Data System (ADS)

Semelsberger, Troy A.; Borup, Rodney L.

The production of a hydrogen-rich fuel-cell feed by dimethyl ether (DME) steam reforming was investigated using calculations of thermodynamic equilibrium as a function of steam-to-carbon ratio (0.00-4.00), temperature (100-600 °C), pressure (1-5 atm), and product species. Species considered were acetone, acetylene, carbon dioxide, carbon monoxide, dimethyl ether, ethane, ethanol, ethylene, formaldehyde, formic acid, hydrogen, isopropanol, methane, methanol, methyl-ethyl ether, n-propanol and water. Thermodynamic equilibrium calculations of DME steam reforming indicate complete conversion of dimethyl ether to hydrogen, carbon monoxide and carbon dioxide at temperatures greater than 200 °C and steam-to-carbon ratios greater than 1.25 at atmospheric pressure ( P = 1 atm). Increasing the operating pressure shifts the equilibrium toward the reactants; increasing the pressure from 1 to 5 atm decreases the conversion of dimethyl ether from 99.5 to 76.2%. The trend of thermodynamically stable products in decreasing mole fraction is methane, ethane, isopropyl alcohol, acetone, n-propanol, ethylene, ethanol, methyl-ethyl ether and methanol-formaldehyde, formic acid, and acetylene were not observed. Based on the equilibrium calculations, the optimal processing conditions for dimethyl ether steam reforming occur at a steam-to-carbon ratio of 1.50, a pressure of 1 atm, and a temperature of 200 °C. These thermodynamic equilibrium calculations show dimethyl ether processed with steam will produce hydrogen-rich fuel-cell feeds—with hydrogen concentrations exceeding 70%. The conversion of dimethyl ether via hydrolysis (considering methanol as the only product) is limited by thermodynamic equilibrium. Equilibrium conversion increases with temperature and steam-to-carbon ratio. A maximum dimethyl ether conversion of 62% is achieved at a steam-to-carbon ratio of 5.00 and a processing temperature of 600 °C.

Structure and Reactivity of Alkyl Ethers Adsorbed on CeO2(111) Model Catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

F Calaza; T Chen; D Mullins

2011-12-31

The effect of surface hydroxyls on the adsorption of ether on ceria was explored. Adsorption of dimethyl ether (DME) and diethyl ether (DEE) on oxidized and reduced CeO{sub 2}(111) films was studied and compared with Ru(0001) using RAIRS and sXPS within a UHV environment. On Ru(0001) the ethers adsorb weakly with the molecular plane close to parallel to the surface plane. On the ceria films, the adsorption of the ethers was stronger than on the metal surface, presumably due to stronger interaction of the ether oxygen lone pair electrons with a cerium cation. This interaction causes the ethers to tiltmore » away from the surface plane compared to the Ru(0001) surface. No pronounced differences were found between oxidized (CeO{sub 2}) and reduced (CeOx) films. The adsorption of the ethers was found to be perturbed by the presence of OH groups on hydroxylated CeOx. In the case of DEE, the geometry of adsorption resembles that found on Ru, and in the case of dimethyl ether DME is in between that one found on clean CeOx and the metal surface. Decomposition of the DEE was observed on the OH/CeOx surface following high DEE exposure at 300 K and higher temperatures. Ethoxides and acetates were identified as adsorbed species on the surface by means of RAIRS and ethoxides and formates by s-XPS. No decomposition of dimethyl ether was observed on the OH/CeOx at these higher temperatures, implying that the dissociation of the C-O bond from ethers requires the presence of {beta}-hydrogen.« less

Structure and Reactivity of Alkyl Ethers Adsorbed on CeO(2)(111) Model Catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calaza, Florencia C; Chen, Tsung-Liang; Mullins, David R

2011-01-01

The effect of surface hydroxyls on the adsorption of ether on ceria was explored. Adsorption of dimethyl ether (DME) and diethyl ether (DEE) on oxidized and reduced CeO{sub 2}(111) films was studied and compared with Ru(0001) using RAIRS and sXPS within a UHV environment. On Ru(0001) the ethers adsorb weakly with the molecular plane close to parallel to the surface plane. On the ceria films, the adsorption of the ethers was stronger than on the metal surface, presumably due to stronger interaction of the ether oxygen lone pair electrons with a cerium cation. This interaction causes the ethers to tiltmore » away from the surface plane compared to the Ru(0001) surface. No pronounced differences were found between oxidized (CeO{sub 2}) and reduced (CeOx) films. The adsorption of the ethers was found to be perturbed by the presence of OH groups on hydroxylated CeOx. In the case of DEE, the geometry of adsorption resembles that found on Ru, and in the case of dimethyl ether DME is in between that one found on clean CeOx and the metal surface. Decomposition of the DEE was observed on the OH/CeOx surface following high DEE exposure at 300 K and higher temperatures. Ethoxides and acetates were identified as adsorbed species on the surface by means of RAIRS and ethoxides and formates by s-XPS. No decomposition of dimethyl ether was observed on the OH/CeOx at these higher temperatures, implying that the dissociation of the C-O bond from ethers requires the presence of {beta}-hydrogen.« less

Effect of p-amino-diphenyl ethers on hepatic microsomal cytochrome P450.

PubMed

Jiang, Huidi; Xuan, Guida

2003-09-01

The present paper aims to investigate whether p-amino-2',4'-dichlorodiphenyl ether and p-amino-4'-methyldiphenyl ether are inhibitors as well as inducers of P450. Mice were given daily intraperitoneal (ip) injections of p-amino-2',4'-dichlorodiphenyl ether (0.25 mmol/kg) or p-amino-4'-methyldiphenyl ether (0.25 mmol/kg) for 4 days and tested at 24 h and 48 h after the last dose injection. The results showed the mice pentobarbital sleeping time was shorter and the P450 content of hepatic microsome increased significantly in the group pretreated with p-amino-4'-methyldiphenyl ether when compared with the control group, while in mice pretreated with p-amino-2',4'-dichlorodiphenyl ether the hepatic microsome P450 content increased but the pentobarbital sleeping time was extended in clear contrast to the control group. The sleeping time of the phenobarbital group (80 mg/kg daily ip injection for 4 days) was shortened at 24 h after the last injection with increased P450 content of hepatic microsome, but it showed no difference at 48 h. The zoxazolamine-paralysis times of mice treated with p-amino-2',4'-dichlorodiphenyl ether were longer than those of the control mice, while the same dose of zoxazolamine did not lead to paralysis in mice pretreated with BNF. p-Amino-2',4'-dichlorodiphenyl ether and p-amino-4'-methyldiphenyl ether inhibited the activity of 7-ethoxyresorufin O-deethylase from rat hepatic microsome induced by BNF in vitro by 70.0% and 50.1% respectively. These results suggest that p-amino-2',4'-dichlorodiphenyl ether and p-amino-4'-methyldiphenyl ether are inhibitors as well as inducers of P450.

URANIUM PURIFICATION PROCESS

DOEpatents

Winters, C.E.

1957-11-12

A method for the preparation of a diethyl ether solution of uranyl nitrate is described. Previously the preparation of such ether solutions has been difficult and expensive, since crystalline uranyl nitrate hexahydrate dissolves very slowly in ether. An improved method for effecting such dissolution has been found, and it comprises adding molten uranyl nitrate hexahydrate at a temperature of 65 to 105 deg C to the ether while maintaining the temperature of the ether solvent below its boiling point.

VARIATION OF THE VISCOSITY OF CERTAIN GAS-OXYGEN MIXTURES UNDER THE INFLUENCE OF MAGNETIC FIELD; Variatia Viscozitatii unor Amestecuri de Gaze cu Oxigen sub Influenta unui Cimp Magnetic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ursu, I.

1958-01-01

The paramagnetic effects of oxygen and gas-oxygen mixtures are discussed. One of the paramagnetic effect the varistion of viscosity during the viscous flow in a magnetic field. The viscosity of gaseous oxygen and certain gas-oxygen mixtures decreased when the flow occurred in a magnetic field. The dependence of this effect on the size of the capillaries and porous materials was investigated. The viscosity was also found to vary with the concentration of oxygen and the other components forming the mixture. The results of the investigations with various gas mixtures are graphically shown. (A.C.)

[Early contributions from Erlangen to the theory and practice of ether and chloroform anesthesia. 1. Heyfelder's clinical trial with ether and chloroform].

PubMed

Hintzenstern, U v; Schwarz, W

1996-02-01

The era of modern anaesthesia in Germany began on January 24th, 1847. This day, professor in ordinary Johann Ferdinand Heyfelder anaesthetized a patient with sulphuric ether in the clinic of surgery and ophthalmology of the University of Erlangen. By March 17th, 1847, Heyfelder had performed 121 surgical procedures under ether. The operations in majority were teeth-extractions, and a few more complex operations such as the treatment of a harelip or of lip cancer or the resection of the shoulder joint. Heyfelder described in detail 108 of these inhalations in a little book entitled The experiments with sulphuric ether. This monograph published in March, 1847, represents one of the first complete dissertations on sulphuric ether in the German literature. In a special chapter he analyzed the development of various physiological and psychological parameters during etherization. Heyfelder also examined blood and urine of some etherized patients and reported that he did not find any important or specific alterations. In 1847, Heyfelder was probably the first to apply salt-ether in man. After 4 administrations he concluded that salt ether acted more quickly but shorter than sulphuric ether. Advantageous were its application without problems and ease of induction. Disadvantageous were its high volatility, its price and the difficulty of getting it in a pure form. From December, 1847, on Heyfelder started to use chloroform. He was now able to perform more major operations, for example, the total resection of the hip-joint. In his book The experiments with sulphuric ether, salt ether, and chloroform he describes a great number of anaesthetic administrations using these 3 agents. In his summary Heyfelder concluded, that chloroform was undoubtly superior to sulphuric ether mainly because it was a quicker acting and longer lasting agent and leads to deeper narcosis. Moreover its application was much easier for it needed no special apparatus. However, because of its great anaesthetic potency, Heyfelder particularly demanded great caution in the application of chloroform. Explicitely he expected an assistant for chloroformizations, whose only duty was to supervise the inhalations and the patient--a forerunner of the modern specialized anaesthesiologist.

Amended final report on the safety assessment of PPG-40 butyl ether with an addendum to include PPG-2, -4, -5, -9, -12, -14, -15, -16, -17, -18, -20, -22, -24, -26, -30, -33, -52, and -53 butyl ethers.

PubMed

Lanigan, R S

2001-01-01

The Polypropylene Glycol (PPG) Butyl Ethers function as skinand hair-conditioning agents in cosmetics. Intestinal absorption of the PPG Butyl Ethers was inversely proportional to the molecular weight. In general, the toxicity of the PPG Butyl Ethers decreased as the molecular weight increased. In acute studies, moderate intraperitoneal (IP) doses of various PPG Butyl Ethers caused convulsive seizures in mice and anesthetized dogs, and large oral doses caused decreased activity, anuria, renal tubular swelling and necrosis, and hepatic swelling and necrosis. PPG-2 Butyl Ether vapors were nontoxic by the inhalation route. PPG-2 Butyl Ether was nontoxic in short-term feeding and dermal exposure studies in rats. In animal irritation studies, PPG-2 Butyl Ether caused minor, transient erythema and desquamation; in addition, erythema, edema, ecchymosis, necrosis, and other changes were observed during an acute percutaneous study. PPG-2 Butyl Ether also caused minor to moderate conjunctival irritation and minor corneal injury. PPG-2 Butyl Ether when dermally applied was nontoxic to pregnant rats and was nonteratogenic at doses up to 1.0 ml/kg/day. PPG BE800 at concentrations of 0.001% to 0.26% in feed was noncarcinogenic to rats after 2 years of treatment. In clinical studies, PPG BE800 was nonirritating and nonsensitizing to the skin when tested using 200 subjects. PPG-40 Butyl Ether was neither an irritant nor a sensitizer in a repeat-insult patch test using 112 subjects. Although clinical testing did not indicate significant skin irritation is produced by these ingredients, the animal test data did indicate the potential that these ingredients can be irritating. Therefore, it was concluded that the PPG Butyl Ethers can be used safely in cosmetic products if they are formulated to avoid irritation. Data on the component ingredients, Propylene Glycol, PPG, and n-Butyl Alcohol, from previous cosmetic ingredient safety assessments were also considered and found to support the safety of PPG Butyl Ethers.

Zebrafish seizure model identifies p,p -DDE as the dominant contaminant of fetal California sea lions that accounts for synergistic activity with domoic acid.

PubMed

Tiedeken, Jessica A; Ramsdell, John S

2010-04-01

Fetal poisoning of California sea lions (CSLs; Zalophus californianus) has been associated with exposure to the algal toxin domoic acid. These same sea lions accumulate a mixture of persistent environmental contaminants including pesticides and industrial products such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Developmental exposure to the pesticide dichlorodiphenyltrichloroethane (DDT) and its stable metabolite 1,1-bis-(4-chlorophenyl)-2,2-dichloroethene (p,p -DDE) has been shown to enhance domoic acid-induced seizures in zebrafish; however, the contribution of other co-occurring contaminants is unknown. We formulated a mixture of contaminants to include PCBs, PBDEs, hexachlorocyclohexane (HCH), and chlordane at levels matching those reported for fetal CSL blubber to determine the impact of co-occurring persistent contaminants with p,p -DDE on chemically induced seizures in zebrafish as a model for the CSLs. Embryos were exposed (6-30 hr postfertilization) to p,p -DDE in the presence or absence of a defined contaminant mixture prior to neurodevelopment via either bath exposure or embryo yolk sac microinjection. After brain maturation (7 days postfertilization), fish were exposed to a chemical convulsant, either pentylenetetrazole or domoic acid; resulting seizure behavior was then monitored and analyzed for changes, using cameras and behavioral tracking software. Induced seizure behavior did not differ significantly between subjects with embryonic exposure to a contaminant mixture and those exposed to p,p -DDE only. These studies demonstrate that p,p -DDE--in the absence of PCBs, HCH, chlordane, and PBDEs that co-occur in fetal sea lions--accounts for the synergistic activity that leads to greater sensitivity to domoic acid seizures.

Influence of sediment chemistry and sediment toxicity on macroinvertebrate communities across 99 wadable streams of the Midwestern USA

USGS Publications Warehouse

Moran, Patrick W.; Nowell, Lisa H.; Kemble, Nile E.; Mahler, Barbara J.; Waite, Ian R.; Van Metre, Peter C.

2017-01-01

Simultaneous assessment of sediment chemistry, sediment toxicity, and macroinvertebrate communities can provide multiple lines of evidence when investigating relations between sediment contaminants and ecological degradation. These three measures were evaluated at 99 wadable stream sites across 11 states in the Midwestern United States during the summer of 2013 to assess sediment pollution across a large agricultural landscape. This evaluation considers an extensive suite of sediment chemistry totaling 274 analytes (polycyclic aromatic hydrocarbons, organochlorine compounds, polychlorinated biphenyls, polybrominated diphenyl ethers, trace elements, and current-use pesticides) and a mixture assessment based on the ratios of detected compounds to available effects-based benchmarks. The sediments were tested for toxicity with the amphipod Hyalella azteca (28-d exposure), the midge Chironomus dilutus (10-d), and, at a few sites, with the freshwater mussel Lampsilis siliquoidea (28-d). Sediment concentrations, normalized to organic carbon content, infrequently exceeded benchmarks for aquatic health, which was generally consistent with low rates of observed toxicity. However, the benchmark-based mixture score and the pyrethroid insecticide bifenthrin were significantly related to observed sediment toxicity. The sediment mixture score and bifenthrin were also significant predictors of the upper limits of several univariate measures of the macroinvertebrate community (EPT percent, MMI (Macroinvertebrate Multimetric Index) Score, Ephemeroptera and Trichoptera richness) using quantile regression. Multivariate pattern matching (Mantel-like tests) of macroinvertebrate species per site to identified contaminant metrics and sediment toxicity also indicate that the sediment mixture score and bifenthrin have weak, albeit significant, influence on the observed invertebrate community composition. Together, these three lines of evidence (toxicity tests, univariate metrics, and multivariate community analysis) suggest that elevated contaminant concentrations in sediments, in particular bifenthrin, is limiting macroinvertebrate communities in several of these Midwest streams.

A comparison of complexation of Li+ ion with macrocyclic ligands 15-crown-5 and 12-crown-4 in binary nitromethane-acetonitrile mixtures by using lithium-7 NMR technique and ab initio calculation.

PubMed

Alizadeh, Nina

2011-01-01

Lithium-7 NMR measurements were used to investigate the stoichiometry and stability of Li+ complexes with 15-crown-5 (15C5), benzo-15-crown-5 (B15C5), dibenzo-15-crown-5 (DB15C5) and 12-crown-4 (12C4) in a number of nitromethane (NM)-acetonitrile (AN) binary mixtures. In all cases, the exchange between the free and complexed lithium ion was fast on the NMR time scale and a single population average resonance was observed. While all crown ethers form 1:1 complexes with Li+ ion in the binary mixtures used, both 1:1 and 2:1 (sandwich) complexes were observed between lithium ion and 12C4 in pure nitromethane solution. Stepwise formation constants of the 1:1 and 2:1 (ligand/metal) complexes were evaluated from computer fitting of the NMR-mole ratio data to equations which relate the observed metal ion chemical shifts to formation constants. There is an inverse linear relationship between the logarithms of the stability constants and the mole fraction of acetonitrile in the solvent mixtures. The stability order of the 1:1 complexes was found to be 15C5·Li+>B15C5·Li+>DB15C5·Li+>12C4·Li+. The optimized structures of the free ligands and their 1:1 and 2:1 complexes with Li+ ion were predicted by ab initio theoretical calculations using the Gaussian 98 software, and the results are discussed. Copyright © 2010 Elsevier B.V. All rights reserved.

Comparison of clinical results for the use of ethyl acetate and diethyl ether in the formalin-ether sedimentation technique performed on polyvinyl alcohol-preserved specimens.

PubMed Central

Garcia, L S; Shimizu, R

1981-01-01

One hundred fecal specimens preserved in polyvinyl alcohol fixative were examined by the Formalin-ether sedimentation technique with ethyl acetate substituted for diethyl ether. Technical performance of the procedures, appearance and amount of sediment obtained, and organism morphology were comparable. Also, ethyl acetate is less flammable and, therefore, less dangerous to use than diethyl ether. Results of parasite recovery when diethyl ether or ethyl acetate was used revealed few clinical relevant differences, most of which could also have been attributed to other variables inherent in this type of diagnostic testing. PMID:7229014

Propenyl ether monomers for photopolymerization

DOEpatents

Crivello, J.V.

1996-10-22

Propenyl ether monomers of formula A(OCH{double_bond}CHCH{sub 3}){sub n} wherein n is an integer from one to six and A is selected from cyclic ethers, polyether and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of the above formula together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

Propenyl ether monomers for photopolymerization

DOEpatents

Crivello, James V.

1996-01-01

Propenyl ether monomers of formula V A(OCH.dbd.CHCH.sub.3).sub.n wherein n is an integer from one to six and A is selected from cyclic ethers, polyether and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of formula V together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

Process for making propenyl ethers and photopolymerizable compositions containing them

DOEpatents

Crivello, James V.

1996-01-01

Propenyl ether monomers of formula V A(OCH.dbd.CHCH.sub.3).sub.n wherein n is an integer from one to six and A is selected from cyclic ethers, polyether and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of formula V together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

Mechanisms of selective cleavage of C–O bonds in di-aryl ethers in aqueous phase

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Jiayue; Zhao, Chen; Mei, Donghai

2014-01-01

A novel route for cleaving the C-O aryl ether bonds of p-substituted H-, CH 3-, and OH- diphenyl ethers has been explored over Ni/SiO 2 catalysts at very mild conditions. The C-O bond of diphenyl ether is cleaved by parallel hydrogenolysis and hydrolysis (hydrogenolysis combined with HO* addition) on Ni. The rates as a function of H 2 pressure from 0 to 10 MPa indicate that the rate-determining step is the C-O bond cleavage on Ni. H* atoms compete with the organic reactant for adsorption leading to a maximum in the rate with increasing H 2 pressure. In contrast tomore » diphenyl ether, hydrogenolysis is the exclusive route for cleaving an ether C-O bond of di-p-tolyl ether to form p-cresol and toluene. 4,4'-dihydroxydiphenyl ether undergoes sequential surface hydrogenolysis, first to phenol and HOC 6H 4O* (adsorbed), which is then cleaved to phenol (C 6H 5O* with added H*) and H 2O (O* with two added H*) in a second step. Density function theory supports the operation of this pathway. Notably, addition of H* to HOC 6H 4O* is less favorable than a further hydrogenolytic C-O bond cleavage. The TOFs of three aryl ethers with Ni/SiO 2 in water followed the order 4,4'-dihydroxydiphenyl ether (69 h -1) > diphenyl ether (26 h -1) > di-p-tolyl ether (1.3 h -1), in line with the increasing apparent activation energies, ranging from 93 kJ∙mol -1 (4,4'-dihydroxydiphenyl ether) < diphenyl ether (98 kJ∙mol -1) to di-p-tolyl ether (105 kJ∙mol -1). D.M. thanks the support from the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle. Computing time was granted by the grand challenge of computational catalysis of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) and by the National Energy Research Scientific Computing Center (NERSC). EMSL is a national scientific user facility located at Pacific Northwest National Laboratory (PNNL) and sponsored by DOE’s Office of Biological and Environmental Research.« less

40 CFR 721.10017 - Amine terminated bisphenol A diglycidyl ether polymer (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... diglycidyl ether polymer (generic). 721.10017 Section 721.10017 Protection of Environment ENVIRONMENTAL... ether polymer (generic). (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as amine terminated bisphenol A diglycidyl ether polymer (PMNs P...

40 CFR 721.1580 - Disubstituted benzene ether, polymer with substituted phenol (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Disubstituted benzene ether, polymer... Significant New Uses for Specific Chemical Substances § 721.1580 Disubstituted benzene ether, polymer with... chemical substance generically identified as disubstituted benzene ether, polymer with substituted phenol...

40 CFR 721.10017 - Amine terminated bisphenol A diglycidyl ether polymer (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... diglycidyl ether polymer (generic). 721.10017 Section 721.10017 Protection of Environment ENVIRONMENTAL... ether polymer (generic). (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as amine terminated bisphenol A diglycidyl ether polymer (PMNs P...

40 CFR 721.3438 - Chlorohydroxyalkyl butyl ether (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Chlorohydroxyalkyl butyl ether... Specific Chemical Substances § 721.3438 Chlorohydroxyalkyl butyl ether (generic). (a) Chemical substance... chlorohydroxyalkyl butyl ether (PMN P-99-1295) is subject to reporting under this section for the significant new use...

40 CFR 721.3438 - Chlorohydroxyalkyl butyl ether (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Chlorohydroxyalkyl butyl ether... Specific Chemical Substances § 721.3438 Chlorohydroxyalkyl butyl ether (generic). (a) Chemical substance... chlorohydroxyalkyl butyl ether (PMN P-99-1295) is subject to reporting under this section for the significant new use...

40 CFR 721.10017 - Amine terminated bisphenol A diglycidyl ether polymer (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... diglycidyl ether polymer (generic). 721.10017 Section 721.10017 Protection of Environment ENVIRONMENTAL... ether polymer (generic). (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as amine terminated bisphenol A diglycidyl ether polymer (PMNs P...

40 CFR 721.10017 - Amine terminated bisphenol A diglycidyl ether polymer (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... diglycidyl ether polymer (generic). 721.10017 Section 721.10017 Protection of Environment ENVIRONMENTAL... ether polymer (generic). (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as amine terminated bisphenol A diglycidyl ether polymer (PMNs P...

40 CFR 721.10017 - Amine terminated bisphenol A diglycidyl ether polymer (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... diglycidyl ether polymer (generic). 721.10017 Section 721.10017 Protection of Environment ENVIRONMENTAL... ether polymer (generic). (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as amine terminated bisphenol A diglycidyl ether polymer (PMNs P...

40 CFR 721.1580 - Disubstituted benzene ether, polymer with substituted phenol (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Disubstituted benzene ether, polymer... Significant New Uses for Specific Chemical Substances § 721.1580 Disubstituted benzene ether, polymer with... chemical substance generically identified as disubstituted benzene ether, polymer with substituted phenol...

40 CFR 721.1580 - Disubstituted benzene ether, polymer with substituted phenol (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Disubstituted benzene ether, polymer... Significant New Uses for Specific Chemical Substances § 721.1580 Disubstituted benzene ether, polymer with... chemical substance generically identified as disubstituted benzene ether, polymer with substituted phenol...

40 CFR 721.1580 - Disubstituted benzene ether, polymer with substituted phenol (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Disubstituted benzene ether, polymer... Significant New Uses for Specific Chemical Substances § 721.1580 Disubstituted benzene ether, polymer with... chemical substance generically identified as disubstituted benzene ether, polymer with substituted phenol...

40 CFR 721.1580 - Disubstituted benzene ether, polymer with substituted phenol (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Disubstituted benzene ether, polymer... Significant New Uses for Specific Chemical Substances § 721.1580 Disubstituted benzene ether, polymer with... chemical substance generically identified as disubstituted benzene ether, polymer with substituted phenol...

Polybrominated diphenyl ethers in indoor air in Kuwait: Implications for human exposure

NASA Astrophysics Data System (ADS)

Gevao, Bondi; Al-Bahloul, Majed; Al-Ghadban, Abdul Nabi; Ali, Lulwa; Al-Omair, Ali; Helaleh, Murad; Al-Matrouk, Khaled; Zafar, Jamal

Polyurethane foam plug passive samplers were used to concurrently measure air concentrations of polybrominated diphenyl ethers (PBDEs) in 70 indoor environments. PBDEs were detected in all homes and offices investigated with patterns similar to the distribution in the commercial penta technical formulation (Bromkal 70-5DE). The ubiquitous distribution of these compounds in indoor environments may be due to the volatilization of these chemicals from foam (e.g. mattresses, foam padded furniture), electronic equipments (e.g. TVs, printers, computers) and other consumer products to which they are added as flame retardants. Mean ΣPBDEs concentration in air was log-normally distributed and ranged from ˜2-385 pg m -3. Using an inhalation rate of 8 and 20 m 3 day -1 for children and adults respectively, exposure via inhalation is estimated to be 173 and 399 pg day -1 for children and adults respectively. This study supports the growing body of evidence for the ubiquitous presence of these compounds in indoor air and the potential for continuous, low-level exposure both at work and home.

Spiroborate Ester-Mediated Asymmetric Synthesis of β-Hydroxy Ethers and its Conversion to Highly Enantiopure β-Amino Ethers

PubMed Central

Huang, Kun; Ortiz-Marciales, Margarita; Correa, Wildeliz; Pomales, Edgardo; López, Xaira Y.

2009-01-01

Borane-mediated reduction of aryl and alkyl ketones with α-aryl- and α-pyridyloxy groups affords β-hydroxy ethers in high enantiomeric purity (up to 99% ee) and in good yield, using as catalyst 10 mol % of spiroborate ester 1 derived from (S)-diphenylprolinol. Representative β-hydroxy ethers are successfully converted to β-amino ethers, with minor epimerization, by phthalimide substitution under Mitsunobu’s conditions followed by hydrazinolysis, to obtain primary amino ethers or by imide reduction with borane to afford β-2,3-dihydro-1H-isoindol ethers. Non-racemic Mexiletine and nAChR analogues with potential biological activity are also synthesized in excellent yield by mesylation of key β-hydroxy pyridylethers and substitution with 5, 6 and 7 member ring heterocyclic amines. PMID:19413288

Regulation of priority carcinogens and reproductive or developmental toxicants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hooper, K.; LaDou, J.; Rosenbaum, J.S.

In California, 370 carcinogens and 112 reproductive/developmental toxicants have been identified as a result of the State's Safe Drinking Water and Toxic Enforcement Act of 1986. They include pesticides, solvents, metals, industrial intermediates, environmental mixtures, and reactive agents. Occupational, environmental, and consumer product exposures that involve these agents are regulated under the Act. At levels of concern, businesses must provide warnings for and limit discharges of those chemicals. The lists of chemicals were compiled following systematic review of published data, including technical reports from the U.S. Public Health Service--National Toxicology Program (NTP), and evaluation of recommendations from authoritative bodies suchmore » as the International Agency for Research on Cancer (IARC) and the U.S. Environmental Protection Agency (USEPA). Given the large number of chemicals that are carcinogens or reproductive/developmental toxicants, regulatory concerns should focus on those that have high potential for human exposure, e.g., widely distributed or easily absorbed solvents, metals, environmental mixtures, or reactive agents. In this paper, we present a list of 33 potential priority carcinogens and reproductive/developmental toxicants, including alcoholic beverages, asbestos, benzene, chlorinated solvents, formaldehyde, glycol ethers, lead, tobacco smoke, and toluene.« less

Electrolytes for Low-Temperature Operation of Li-CFx Cells

NASA Technical Reports Server (NTRS)

Smart, Marshall C.; Whitacre, Jay F.; Bugga, Ratnakumar V.; Prakash, G. K. Surya; Bhalla, Pooja; Smith, Kiah

2009-01-01

A report describes a study of electrolyte compositions selected as candidates for improving the low-temperature performances of primary electrochemical cells that contain lithium anodes and fluorinated carbonaceous (CFx) cathodes. This study complements the developments reported in Additive for Low-Temperature Operation of Li-(CF)n Cells (NPO- 43579) and Li/CFx Cells Optimized for Low-Temperature Operation (NPO- 43585), which appear elsewhere in this issue of NASA Tech Briefs. Similar to lithium-based electrolytes described in several previous NASA Tech Briefs articles, each of these electrolytes consisted of a lithium salt dissolved in a nonaqueous solvent mixture. Each such mixture consisted of two or more of the following ingredients: propylene carbonate (PC); 1,2-dimethoxyethane (DME); trifluoropropylene carbonate; bis(2,2,2-trifluoroethyl) ether; diethyl carbonate; dimethyl carbonate; and ethyl methyl carbonate. The report describes the physical and chemical principles underlying the selection of the compositions (which were not optimized) and presents results of preliminary tests made to determine effects of the compositions upon the low-temperature capabilities of Li-CFx cells, relative to a baseline composition of LiBF4 at a concentration of 1.0 M in a solvent comprising equal volume parts of PC and DME.

Are Some Fungal Volatile Organic Compounds (VOCs) Mycotoxins?

PubMed Central

Bennett, Joan W.; Inamdar, Arati A.

2015-01-01

Volatile organic compounds (VOCs) are carbon-compounds that easily evaporate at room temperature. Toxins are biologically produced poisons; mycotoxins are those toxins produced by microscopic fungi. All fungi emit blends of VOCs; the qualitative and quantitative composition of these volatile blends varies with the species of fungus and the environmental situation in which the fungus is grown. These fungal VOCs, produced as mixtures of alcohols, aldehydes, acids, ethers, esters, ketones, terpenes, thiols and their derivatives, are responsible for the characteristic moldy odors associated with damp indoor spaces. There is increasing experimental evidence that some of these VOCs have toxic properties. Laboratory tests in mammalian tissue culture and Drosophila melanogaster have shown that many single VOCs, as well as mixtures of VOCs emitted by growing fungi, have toxic effects. This paper describes the pros and cons of categorizing toxigenic fungal VOCs as mycotoxins, uses genomic data to expand on the definition of mycotoxin, and summarizes some of the linguistic and other conventions that can create barriers to communication between the scientists who study VOCs and those who study toxins. We propose that “volatoxin” might be a useful term to describe biogenic volatile compounds with toxigenic properties. PMID:26402705

Regulation of priority carcinogens and reproductive or developmental toxicants.

PubMed

Hooper, K; LaDou, J; Rosenbaum, J S; Book, S A

1992-01-01

In California, 370 carcinogens and 112 reproductive/developmental toxicants have been identified as a result of the State's Safe Drinking Water and Toxic Enforcement Act of 1986. They include pesticides, solvents, metals, industrial intermediates, environmental mixtures, and reactive agents. Occupational, environmental, and consumer product exposures that involve these agents are regulated under the Act. At levels of concern, businesses must provide warnings for and limit discharges of those chemicals. The lists of chemicals were compiled following systematic review of published data, including technical reports from the U.S. Public Health Service--National Toxicology Program (NTP), and evaluation of recommendations from authoritative bodies such as the International Agency for Research on Cancer (IARC) and the U.S. Environmental Protection Agency (USEPA). Given the large number of chemicals that are carcinogens or reproductive/developmental toxicants, regulatory concerns should focus on those that have high potential for human exposure, e.g., widely distributed or easily absorbed solvents, metals, environmental mixtures, or reactive agents. In this paper, we present a list of 33 potential priority carcinogens and reproductive/developmental toxicants, including alcoholic beverages, asbestos, benzene, chlorinated solvents, formaldehyde, glycol ethers, lead, tobacco smoke, and toluene.

Oak (Quercus frainetto Ten.) honeydew honey--approach to screening of volatile organic composition and antioxidant capacity (DPPH and FRAP assay).

PubMed

Jerković, Igor; Marijanović, Zvonimir

2010-05-25

Two samples of oak honeydew honey were investigated. Headspace solid-phase microextraction (HS-SPME) combined with GC and GC/MS enabled identification of the most volatile organic headspace compounds being dominated by terpenes(mainly cis- and trans-linalool oxides). The volatile and less-volatile organic composition of the samples was obtained by ultrasonic assisted extraction (USE) with two solvents (1:2 (v/v) pentane -diethyl ether mixture and dichloromethane) followed by GC and GC/MS analysis. Shikimic pathway derivatives are of particular interest with respect to the botanical origin of honey and the most abundant was phenylacetic acid (up to 16.4%). Antiradical activity (DPPH assay) of the honeydew samples was 4.5 and 5.1 mmol TEAC/kg. Ultrasonic solvent extracts showed several dozen times higher antiradical capacity in comparison to the honeydew. Antioxidant capacity (FRAP assay) of honeydew samples was 4.8 and 16.1 mmol Fe(2+)/kg, while the solvent mixture extracts showed antioxidant activity of 374.5 and 955.9 Fe(2+)/kg, respectively, and the dichloromethane extracts 127.3 and 101.5 mmol Fe(2+)/kg.

Study on simultaneous recycling of EAF dust and plastic waste containing TBBPA.

PubMed

Grabda, Mariusz; Oleszek, Sylwia; Shibata, Etsuro; Nakamura, Takashi

2014-08-15

In the present work we investigated the fates of zinc, lead, and iron present in electric arc furnace dust during thermal treatment of the dust with tetrabromobisphenol A (TBBPA) and tetrabromobisphenol A diglycidyl ether (TBBPADGE). Mixtures of these materials were compressed into pellets and heated in a laboratory-scale furnace at 550 °C for 80 min, under oxidizing and inert conditions. The solid, condensed, and gaseous-phase products were characterized using an array of analytical methods: scanning electron microscopy, X-ray diffraction, electron probe microscopy, inductively coupled plasma, ion chromatography, and gas chromatography. The results indicated that heating the mixtures under specific conditions enabled high separation of zinc and lead from iron-rich residues, by a bromination-evaporation process. In the case of TBBPADGE, a maximum of 85% of zinc and 81% of lead were effectively separated under the above conditions. The process is based on the reaction between the highly reactive HBr gas evolved during thermal degradation of the flame-retarded materials with zinc (ZnO and ZnFe2O4) and lead in the dust, followed by complete evaporation of the formed metallic bromides from the solid residue. Copyright © 2014 Elsevier B.V. All rights reserved.

Anti-Helicobacter pylori activity of anacardic acids from Amphipterygium adstringens.

PubMed

Castillo-Juárez, Israel; Rivero-Cruz, Fausto; Celis, Heliodoro; Romero, Irma

2007-10-08

Amphipterygium adstringens (Schltdl.) Standl. (Anacardiaceae) is widely used in traditional Mexican medicine for the treatment of gastritis and ulcers. In this work, we studied the anti-Helicobacter pylori activity of its bark, this Gram-negative bacterium is considered the major etiological agent of chronic active gastritis and peptic ulcer disease, and it is linked to gastric carcinoma. From a bio-guided assay of the fractions obtained form a continuous Soxhlet extraction of the bark, we identified that petroleum ether fraction had significant antimicrobial activity against Helicobacter pylori. From this fraction, we isolated an anacardic acids mixture and three known triterpenes: masticadienonic acid; 3alpha-hydroxymasticadienonic acid; 3-epi-oleanolic; as well as the sterol beta-sitosterol. Only the anacardic acids mixture exhibits a potent dose-dependent antibacterial activity (MIC=10 microg/ml in broth cultures). It is enriched in saturated alkyl phenolic acids (C15:0, C16:0, C17:0 C19:0) which represents a novel source of these compounds with potent anti-Helicobacter pylori activity. The promising use of anacardic acids and Amphipterygium adstringens bark in the development of an integral treatment of Helicobacter pylori diseases is discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Xin -Yu; Bhagatwala, Ankit; Chen, Jacqueline H.

In this study, the modeling of mixing by molecular diffusion is a central aspect for transported probability density function (tPDF) methods. In this paper, the newly-proposed shadow position mixing model (SPMM) is examined, using a DNS database for a temporally evolving di-methyl ether slot jet flame. Two methods that invoke different levels of approximation are proposed to extract the shadow displacement (equivalent to shadow position) from the DNS database. An approach for a priori analysis of the mixing-model performance is developed. The shadow displacement is highly correlated with both mixture fraction and velocity, and the peak correlation coefficient of themore » shadow displacement and mixture fraction is higher than that of the shadow displacement and velocity. This suggests that the composition-space localness is reasonably well enforced by the model, with appropriate choices of model constants. The conditional diffusion of mixture fraction and major species from DNS and from SPMM are then compared, using mixing rates that are derived by matching the mixture fraction scalar dissipation rates. Good qualitative agreement is found, for the prediction of the locations of zero and maximum/minimum conditional diffusion locations for mixture fraction and individual species. Similar comparisons are performed for DNS and the IECM (interaction by exchange with the conditional mean) model. The agreement between SPMM and DNS is better than that between IECM and DNS, in terms of conditional diffusion iso-contour similarities and global normalized residual levels. It is found that a suitable value for the model constant c that controls the mixing frequency can be derived using the local normalized scalar variance, and that the model constant a controls the localness of the model. A higher-Reynolds-number test case is anticipated to be more appropriate to evaluate the mixing models, and stand-alone transported PDF simulations are required to more fully enforce localness and to assess model performance.« less

An a priori DNS study of the shadow-position mixing model

DOE PAGES

Zhao, Xin -Yu; Bhagatwala, Ankit; Chen, Jacqueline H.; ...

2016-01-15

In this study, the modeling of mixing by molecular diffusion is a central aspect for transported probability density function (tPDF) methods. In this paper, the newly-proposed shadow position mixing model (SPMM) is examined, using a DNS database for a temporally evolving di-methyl ether slot jet flame. Two methods that invoke different levels of approximation are proposed to extract the shadow displacement (equivalent to shadow position) from the DNS database. An approach for a priori analysis of the mixing-model performance is developed. The shadow displacement is highly correlated with both mixture fraction and velocity, and the peak correlation coefficient of themore » shadow displacement and mixture fraction is higher than that of the shadow displacement and velocity. This suggests that the composition-space localness is reasonably well enforced by the model, with appropriate choices of model constants. The conditional diffusion of mixture fraction and major species from DNS and from SPMM are then compared, using mixing rates that are derived by matching the mixture fraction scalar dissipation rates. Good qualitative agreement is found, for the prediction of the locations of zero and maximum/minimum conditional diffusion locations for mixture fraction and individual species. Similar comparisons are performed for DNS and the IECM (interaction by exchange with the conditional mean) model. The agreement between SPMM and DNS is better than that between IECM and DNS, in terms of conditional diffusion iso-contour similarities and global normalized residual levels. It is found that a suitable value for the model constant c that controls the mixing frequency can be derived using the local normalized scalar variance, and that the model constant a controls the localness of the model. A higher-Reynolds-number test case is anticipated to be more appropriate to evaluate the mixing models, and stand-alone transported PDF simulations are required to more fully enforce localness and to assess model performance.« less

Effects of graded levels of liquid brewer's yeast on chemical composition and fermentation quality in cassava pulp and rice straw-based total mixed ration silage.

PubMed

Kamphayae, Sukanya; Kumagai, Hajime; Bureenok, Smerjai; Narmseelee, Ramphrai; Butcha, Patima

2017-04-01

This study aimed to evaluate the effect of liquid brewer's yeast (LBY) addition on chemical composition and fermentation quality of mixture of LBY and cassava pulp (CVP) with rice straw (RS) in different ratios during preservation periods. Four mixtures of LBY, CVP and RS were made, that is mixture ratio of LBY : CVP : RS of 0% LBY, 20% LBY, 35% LBY and 50% LBY were 0:70:30, 20:50:30, 35:35:30 and 50:20:30 as fresh matter, respectively. The bags were opened at weeks 0, 1, 2, 4 and 8 after storage. The contents of dry matter, organic matter, crude protein (CP), ether extract (EE), neutral detergent fiber and acid detergent fiber ranged 36.4-40.0, 88.9-90.8, 4.0-12.0, 1.1-1.3, 58.8-61.6 and 37.6-40.0, respectively, and the contents of CP and EE increased and the other components decreased in proportion to LBY inclusion (P < 0.01). 50% LBY had the highest (P < 0.05) pH (4.81) and ammonia nitrogen per total nitrogen (NH 3 -N/TN) (7.40%) and the lowest V-score (90.3). Propionic and butyric acid contents were 0.01% or lower in each mixture and storage period. There were rapid pH decrease and NH 3 -N/TN increase during the first week of the storage period. The increases of NH 3 -N/TN and acetic acid content and decreases of pH, lactic acid content and V-score during the preservation were more drastic as LBY inclusion increased. Although higher proportion of LBY produced higher CP and lower fiber contents in the mixture, attention should be paid for the reduction of fermentation quality during longer storage periods. © 2016 Japanese Society of Animal Science.

Cumulative toxicity of an environmentally relevant mixture of nine regulated disinfection by-products in a multigenerational rat reproductive bioassay

EPA Science Inventory

CUMULATIVE TOXICITY OF AN ENVIRONMENTALLY RELEVANT MIXTURE OF NINE REGULATED DISINFECTION BY-PRODUCTS IN A MULTIGENERATIONAL RAT REPRODUCTIVE BIOASSAY J E Simmons, GR. Klinefelter, JM Goldman, AB DeAngelo, DS Best, A McDonald, LF Strader, AS Murr, JD Suarez, MH George, ES Hunte...

Alternative Fuels Data Center: Dimethyl Ether

Science.gov Websites

Hydrocarbon Biofuels Dimethyl Ether Dimethyl ether (DME) is a synthetically produced alternative to diesel for use in specially designed compression ignition diesel engines. Under normal atmospheric conditions ether has several fuel properties that make it attractive for use in diesel engines. It has a very high

Novel crosslinked membranes based on sulfonated poly(ether ether ketone) for direct methanol fuel cells.

PubMed

Zhu, Yuanqin; Zieren, Shelley; Manthiram, Arumugam

2011-07-14

Novel covalently crosslinked membranes based on sulfonated poly(ether ether ketone) and carboxylated polysulfone exhibit much lower methanol crossover and better performance in direct methanol fuel cells at 65 °C in 1 and 2 M methanol solutions compared to Nafion 115 membranes.

21 CFR 868.5420 - Ether hook.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ether hook. 868.5420 Section 868.5420 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5420 Ether hook. (a) Identification. An ether hook is a device...

Heavy metal removal mechanisms of sorptive filter materials for road runoff treatment and remobilization under de-icing salt applications.

PubMed

Huber, Maximilian; Hilbig, Harald; Badenberg, Sophia C; Fassnacht, Julius; Drewes, Jörg E; Helmreich, Brigitte

2016-10-01

The objective of this research study was to elucidate the removal and remobilization behaviors of five heavy metals (i.e., Cd, Cu, Ni, Pb, and Zn) that had been fixed onto sorptive filter materials used in decentralized stormwater treatment systems receiving traffic area runoff. Six filter materials (i.e., granular activated carbon, a mixture of granular activated alumina and porous concrete, granular activated lignite, half-burnt dolomite, and two granular ferric hydroxides) were evaluated in column experiments. First, a simultaneous preloading with the heavy metals was performed for each filter material. Subsequently, the remobilization effect was tested by three de-icing salt experiments in duplicate using pure NaCl, a mixture of NaCl and CaCl2, and a mixture of NaCl and MgCl2. Three layers of each column were separated to specify the attenuation of heavy metals as a function of depth. Cu and Pb were retained best by most of the selected filter materials, and Cu was often released the least of all metals by the three de-icing salts. The mixture of NaCl and CaCl2 resulted in a stronger effect upon remobilization than the other two de-icing salts. For the material with the highest retention, the effect of the preloading level upon remobilization was measured. The removal mechanisms of all filter materials were determined by advanced laboratory methods. For example, the different intrusions of heavy metals into the particles were determined. Findings of this study can result in improved filter materials used in decentralized stormwater treatment systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Grignard-like Organic Reaction in Water

NASA Astrophysics Data System (ADS)

Breton, Gary W.; Hughey, Christine A.

1998-01-01

The addition of a Grignard reagent to a carbonyl-containing compound to form an alcohol is an important reaction to demonstrate in organic chemistry laboratory courses. However, the reaction presents several practical problems for the lab instructor including the need for anhydrous solvents (e.g., ether), dry glassware, and the occasional problem of slow reaction initiation. We have scaled, and tested, a known Grignard-like reaction between allyl bromide and benzaldehyde mediated by zinc metal in aqueous media. The procedure retains the desirable features of the traditional Grignard reaction, while eliminating some of the commonly encountered difficulties. Thus, addition of allyl bromide (1.2 eq) to benzaldehyde and zinc in a two-phase mixture of THF and saturated aqueous NH4Cl afforded addition product 1-phenyl-3-buten-1-ol in 70-85% yields.

Synthesis and Mesomorphic Behavior of Poly((2S, 3S)-(+)-2-Chloro-3- Methylpentyl 4’-(Omega-Vinyloxyalkyloxy)biphenyl-4-Carboxylate)s with Ethyl and Propyl Alkyl Groups

DTIC Science & Technology

1994-06-30

1 . Synthesis of (2S, 3S)-(+)-2-chloro-3-methyl-pentyl 4’-(2-vinyloxyethyloxy) biphenyl-4-carboxylate (15-2...CH2)2-),7.65 (d, 3=8.3Hz, 2 ArH, m to -COO-), 8.11 (d, J=7.4Hz, 2 ArH, o to -COO-). 3-Chloroprop~yl- 1 -vinyl ether (13-3) The mixture of 3- chloropropan ...VA .% fo - " A’* *i f’. - % .oL.,ae- a * 1 nOl-6..io. Ocw. ’•.1ý’ ..a.. :l•t :...•.t ;,,31 -. 1 " 1 . 2 . 10 1 -- Of , • l 0’ i’*J.. e t *no suaqetg

Solvent-free catalytic dehydrative etherification of benzyl alcohol over graphene oxide

NASA Astrophysics Data System (ADS)

Yu, Huiyou; Wang, Xinde; Zhu, Yuanshuai; Zhuang, Guilin; Zhong, Xing; Wang, Jian-guo

2013-09-01

Graphene oxide (GO), prepared from oxidation of graphite powders using a modified Hummers method, exhibits a promising catalytic activity and a high selectivity for the solvent-free catalytic dehydrative etherification of benzyl alcohol (BA). A maximum yield (85.4%) of dibenzyl ether (DE) was achieved at 150 °C for 24 h when the BA/GO ration was 20 ml/g under solvent-free condition. This discovery provided a new insight into the development of GO as a carbocatalysts for a variety of applications in carbocatalysis.

Taxonomic status and biology of the Cuban blackhawk, Buteogallus anthracinus gundlachii (AVES: Accipitridae)

USGS Publications Warehouse

Wiley, J.W.; Garrido, O.H.

2005-01-01

We reevaluate the taxonomic status of the Cuban population of the Common Black-Hawk (Buteogallus anthracinus) based on our examination of additional specimens, nests, eggs, and voice data. Buteogallus a. gundlachii is smaller than mainland populations of anthracinus and differs from mainland birds in plumage coloration and pattern. The common (alarm) call of gundlachii is a series of three or four notes, differing from that of mainland anthracinus, whose call consists of 9-24 notes. In the Isla de Pinos, Cuba, we observed gundlachii eating two species of land crabs (71.4%), centipedes (7.1%), lizards (10.7%), mammals (7.1%), and a bird (3.6%). We consider Buteogallus gundlachii Cabanis 1854 (1855), the Cuban Black-Hawk, to be a full species, endemic to Cuba, Isla de Pinos, and many of the cays of the Cuban Archipelago. ?? 2005 The Raptor Research Foundation, Inc.

Effect of Non-laminar Regime on the Efficiency of a Thermal Diffusion Column. Report No. 26; INFLUENCIA DEL REGIMEN NO LAMINAR SOBRE LA EFICIENCIA DE UNA COLUMNA DE DIFUSION TERMICA. Informe No. 26

DOE Office of Scientific and Technical Information (OSTI.GOV)

Espanol, C.E.

1960-01-01

The effect of the appearance of localized perturbations on the separation factor and operation time of a thermal diffusion column is studied. The separation factor of a column was obtained experimentally and the enrichment was recorded continuously as a function of time by measurement of the thermal conductivity of the gaseous mixture at the foot and head of the column. A mixture of Ar and CO/sub 2/ was used as it behaves as an isotopic mixture. The results showed the linear decrease of the separation factor with the number of stages and the operation time practically does not vary. Themore » introduction of localized turbulences in a thermal diffusion column reduces the column yield. (J.S.R.)« less

A Uniform Approach to Type Theory

DTIC Science & Technology

1989-01-01

logical and statistical techniques. There is no comprehensive survey on implementation issues. Some partial aspects are described in...U. de Paris (1930). In: Ecrits logiques de Jacques Herbrand, PUF Paris (1968). [71] C. M. Hoffmann, M. J. O’Donnell. "Programming with Equations

Prevention of renal dysfunction by nutraceuticals prepared from oil rich plant foods

PubMed Central

Al-Okbi, Sahar Y.; Mohamed, Doha A.; Hamed, Thanaa E.; Esmail, Reham SH.; Donya, Souria M.

2014-01-01

Objective To investigate the protective effect of extracts prepared from avocado, walnut, flaxseed and Eruca sativa seeds in a rat model of kidney dysfunction induced by intraperitoneal cisplatin. Methods Ethanol and petroleum ether extracts mixture was prepared from each plant. Six groups of rats were conducted; control healthy, cisplatin group and four test groups where rats were given daily oral dose of each extract mixture before cisplatin injection. Different biochemical and cytogenetic parameters and kidney histopathology were determined. Acute toxicity was tested for the nutraceuticals. Total phenolic contents, fatty acids (FA) and unsaponifiable matter were assessed in the extracts. Results Walnut ethanol extract showed the highest content of total phenolic. FA analysis revealed that all the studied plants were rich in unsaturated FA. Gas-liquid chromatographic investigation of the unsaponifiable matter showed the presence of campesterol, stigmasterol and β-sitosterol in all the studied plants. Cisplatin treatment induced significant increase in plasma urea, creatinine and malondialdehyde along with significant reduction of plasma albumin, total protein, catalase and total antioxidant as well as reduction in creatinine clearance. Histopathological examination proved the induction of kidney dysfunction. Some sorts of chromosomal aberration and sperm-shape abnormalities were noticed after cisplatin treatment. Administration of extracts mixtures produced improvements in biochemical, histopathological and cytogenetic parameters. Conclusions Administration of the studied nutraceuticals proved to possess protective role against cisplatin-induced nephrotoxicity, chromosomal aberration and abnormal sperms. All studied nutraceuticals showed complete safety. PMID:25183331

Boundary lubrication, thermal and oxidative stability of a fluorinated polyether and a perfluoropolyether triazine

NASA Technical Reports Server (NTRS)

Jones, W. R., Jr.; Snyder, C. E., Jr.

1979-01-01

Boundary lubricating characteristics, thermal stability and oxidation-corrosion stability were determined for a fluorinated polyether and a perfluoropolyether triazine. A ball-on-disk apparatus, a tensimeter and oxidation-corrosion apparatus were used. Results were compared to data for a polyphenyl ether and a C-ether. The polyether and triazine yielded better boundary lubricating characteristics than either the polyphenyl ether or C-ether. The polyphenyl ether had the greatest thermal stability (443 C) while the other fluids had stabilities in the range 389 to 397 C. Oxidation-corrosion results indicated the following order of stabilities: perfluoropolyether triazine greater than polyphenylether greater than C-ether greater than fluorinated polyether.

Process for making propenyl ethers and photopolymerizable compositions containing them

DOEpatents

Crivello, J.V.

1996-01-23

Propenyl ether monomers of formula A(OCH{double_bond}CHCH{sub 3}){sub n} (V) wherein n is an integer from one to six and A is selected from cyclic ethers, polyether, and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of formula V together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

[In Process Citation].

PubMed

Caravalí-Meza, Nuris Yohana; Jiménez-Cruz, Arturo; Bacardí-Gascón, Montserrat

2016-03-25

Antecedentes: se ha reportado una asociación entre el aumento del consumo de bebidas azucaradas y varias enfermedades metabólicas. Objetivo: evaluar el efecto del consumo de bebidas azucaradas sobre la obesidad en un periodo de 12 meses en mexicanos de 15 a 19 años. Métodos: el diseño del estudio fue prospectivo, con 12 meses de seguimiento. Se midieron el peso, la talla y la circunferencia de cintura (CC), y se calculó el puntaje z de índice de masa corporal (IMC). Se aplicó un cuestionario sobre consumo de 19 bebidas. Para evaluar la predicción del aumento de IMC y de CC como resultado del consumo de bebidas, se utilizó análisis de regresión logística binomial. Resultados: al final del estudio se evaluó al 89% (1.344). El promedio de edad fue de 15 años, 55% fueron mujeres. La prevalencia de sobre- peso y obesidad al final del estudio fue del 33%. Al final del estudio, un 25% de los participantes consumían más de 50 g de azúcar proveniente de las bebidas. Quienes consumieron 50 g de azúcar o más al día presentaron mayor riesgo de aumentar la CC ≥ 2 cm (RR = 1,19, IC 95%, 1,03-1,39, p = 0,02). Quienes mantuvieron el consumo de bebidas azucaradas durante 12 meses, al compararlo con los que disminuyeron el consumo a 10 g/día, presentaron 71% más probabilidades de aumentar a un puntaje de IMC ≥ 2 (RR = 1,71, IC 95%, 1,03-2,86, p = 0,039). Conclusión: el alto consumo de bebidas azucaradas aumentó las probabilidades de aumentar de peso y de circunferencia de cintura.

Application of aluminum-supported Pd, Rh, and Rh-Pd nanoparticles in supercritical carbon dioxide system for hydrodebromination of polybrominated diphenyl ethers.

PubMed

Wu, Ben-Zen; Sun, Yu-Jie; Chen, Yan-Hua; Yak, Hwa Kwang; Yu, Jya-Jyun; Liao, Weisheng; Chiu, KongHwa; Peng, Shie-Ming

2016-08-01

Al-powder-supported Pd, Rh, and Rh-Pd catalysts were synthesized through a spontaneous redox reaction in aqueous solutions. These catalysts hydrodebrominated 4- and 4,4'-bromodiphenyl ethers in supercritical carbon dioxide at 200 atm CO2 containing 10 atm H2 and 80 °C in 1 h. Diphenyl ether was the major product of Pd/Al. Rh/Al and Rh-Pd/Al further hydrogenated two benzene rings of diphenyl ether to form dicyclohexyl ether. The hydrogenolysis of CO bonds on diphenyl ether over Rh/Al and Rh-Pd/Al was observed to generate cyclohexanol and cyclohexane (<1%). With respect to hydrodebromination efficiency and catalyst stability, Rh-Pd/Al among three catalysts is suggested to be used for ex situ degradation of polybrominated diphenyl ethers in supercritical carbon dioxide. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of tourism and trade on intestinal parasitic infections in Guatemala.

PubMed

Jensen, L A; Marlin, J W; Dyck, D D; Laubach, H E

2009-04-01

A survey was performed to determine if infection with gastrointestinal parasites differs between the rural and urban poor inhabitants of Guatemala. A total of 317 stool samples from children in two towns, one rural and one urban, were examined using the formalin-ether concentration method. The overall prevalence of parasites in infected children was 67%, 20%, 30%, and 22%, respectively for Ascaris lumbricoides, Trichuris trichiura, Giardia duodenalis and Entamoeba histolytica in the rural town of La Mano de Leon and 49%, 14%, 15%, and 21%, respectively in the urban town of Santa Maria de Jesus. Two sub-studies were carried out to determine the effects of (1) gender and (2) age on the rate of parasitic infections. Female children in the 1-to 6-year-olds age group in Santa Maria de Jesus had more infections with A. lumbricoides and T. trichiura when compared to La Mano de Leon. A. lumbricoides was most prevalent in Santa Maria de Jesus. These results propose that accessibility to tourism and trade decreases the risk for the establishment of parasitic diseases in children of Guatemala possibly due to improvements in basic nutrition and availability of health care.

Orientational glasses. II. Calculation of critical thresholds in ACNxMn{1-x} mixtures

NASA Astrophysics Data System (ADS)

Galam, Serge; Depondt, Philippe

1992-10-01

Using a simple steric hindrance based idea, critical thresholds which occur in the phase diagram of ACNxMn{1-x} mixtures, where A stands for K, Na or Rb while Mn represents Br, Cl or I, are calculated. The cyanide density x is divided into a free-to-reorient part x_r, and a frozen-in part x_f. The latter term x_f is calculated from microscopic characteristics of the molecules involved. Two critical thresholds x_c and x_d for the disappearance of respectively, ferroelastic transitions and ferroelastic domains are obtained. The calculated values are in excellent agreement with available experimental results. Predictions are made for additionnal mixtures. Une idée simple d'encombrement stérique permet de calculer des seuils critiques qui apparaissent dans le diagramme de phase de mélanges ACNxMn{1-x}, où A représente K, Na ou Rb, et Mn, des atoms du type Br, Cl ou I. La concentration x du cyanure est divisée en une partie x_r de molécules libres de se réorienter, et une partie de molécules gelées x_f. Ce dernier terme x_f est calculé à partir des caractéristiques microscopiques des molécules concernées. Deux seuils critiques x_c et x_d pour la disparition respectivement des transitions et des domaines ferroelastiques sont obtenus. Les valeurs calculées sont en excellent accord avec les résultats expérimentaux disponibles. Des prédictions sont faites pour d'autres mélanges.

40 CFR 721.10398 - Poly(oxy-1,2-ethanediyl),. alpha., -monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

...., -monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic). 721.10398 Section 721.10398 Protection of...-ethanediyl),. alpha., -monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic). (a) Chemical substance... poly(oxy-1,2-ethanediyl), .alpha., -monoalkyl ethers-.omega.-mono (hydrogen maleate)- (PMN P-10-495) is...

40 CFR 721.10398 - Poly(oxy-1,2-ethanediyl),. alpha., -monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

...., -monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic). 721.10398 Section 721.10398 Protection of...-ethanediyl),. alpha., -monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic). (a) Chemical substance... poly(oxy-1,2-ethanediyl), .alpha., -monoalkyl ethers-.omega.-mono (hydrogen maleate)- (PMN P-10-495) is...

40 CFR 721.10398 - Poly(oxy-1,2-ethanediyl),. alpha., -monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

...., -monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic). 721.10398 Section 721.10398 Protection of...-ethanediyl),. alpha., -monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic). (a) Chemical substance... poly(oxy-1,2-ethanediyl), .alpha., -monoalkyl ethers-.omega.-mono (hydrogen maleate)- (PMN P-10-495) is...

76 FR 38026 - Diethylene Glycol Mono Butyl Ether; Exemption From the Requirement of a Tolerance

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-29

... chemicals. Immunotoxicity studies were available for ethylene glycol mono butyl ether, also a glycol ether... the glycol ether class of chemicals which include structurally similar chemicals ethylene glycol and... potential to cause cancer. Based on the lack of evidence of carcinogenicity potential for ethylene glycol...

Furfuryl ethyl ether: important aging flavor and a new marker for the storage conditions of beer.

PubMed

Vanderhaegen, Bart; Neven, Hedwig; Daenen, Luk; Verstrepen, Kevin J; Verachtert, Hubert; Derdelinckx, Guy

2004-03-24

Recently, it was reported that furfuryl ethyl ether is an important flavor compound indicative of beer storage and aging conditions. A study of the reaction mechanism indicates that furfuryl ethyl ether is most likely formed by protonation of furfuryl alcohol or furfuryl acetate followed by S(N)2-substitution of the leaving group by the nucleophilic ethanol. For the reaction in beer, a pseudo-first-order reaction kinetics was derived. A close correlation was found between the values predicted by the kinetic model and the actual furfuryl ethyl ether concentration evolution during storage of beer. Furthermore, 10 commercial beers of different types, aged during 4 years in natural conditions, were analyzed, and it was found that the furfuryl ethyl ether flavor threshold was largely exceeded in each type of beer. In these natural aging conditions, lower pH, darker color, and higher alcohol content were factors that enhanced furfuryl ethyl ether formation. On the other hand, sulfite clearly reduced furfuryl ethyl ether formation. All results show that the furfuryl ethyl ether concentration is an excellent time-temperature integrator for beer storage.

Crown ethers in graphene

DOE PAGES

Guo, Junjie; Lee, Jaekwang; Contescu, Cristian I.; ...

2014-11-13

Crown ethers, introduced by Pedersen1, are at their most basic level neutral rings constructed of oxygen atoms linked by two- or three-carbon chains. They have attracted special attention for their ability to selectively incorporate various atoms2 or molecules within the cavity formed by the ring3-6. This property has led to the use of crown ethers and their compounds in a wide range of chemical and biological applications7,8. However, crown ethers are typically highly flexible, frustrating efforts to rigidify them for many uses that demand higher binding affinity and selectivity9,10. In this Letter, we report atomic-resolution images of the same basicmore » structures of the original crown ethers embedded in graphene. This arrangement constrains the crown ethers to be rigid and planar and thus uniquely suited for the many applications that crown ethers are known for. First-principles calculations show that the close similarity of the structures seen in graphene with those of crown ether molecules also extends to their selectivity towards specific metal cations depending on the ring size. Atoms (or molecules) incorporated within the crown ethers in graphene offer a simple environment that can be easily and systematically probed and modeled. Thus, we expect that this discovery will introduce a new wave of investigations and applications of chemically functionalized graphene.« less

Translated Poisson Mixture Model for Stratification Learning (PREPRINT)

DTIC Science & Technology

2007-09-01

del Senyal i Comunicacions Universitat Politècnica de Catalunya, Spain gloria@gps.tsc.upc.edu Gregory Randall Instituto de Ingenierı́a Eléctrica...Universidad de la República, Uruguay randall@fing.edu.uy Guillermo Sapiro Dept. of Electrical and Computer Engineering University of Minnesota, USA guille...NGA, ARO, the McKnight Foundation, and the Juan de la Cierva Program. GH was a postdoctoral associate at Institute of Mathematics and its

Hepatic microsomal metabolism of BDE-47 and BDE-99 by lesser snow geese and Japanese quail.

PubMed

Krieger, Lisa K; Szeitz, András; Bandiera, Stelvio M

2017-09-01

In the present study, we investigated the oxidative biotransformation of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) and 2,2',4,4',5-pentabromodiphenyl ether (BDE-99) by liver microsomes from wild lesser snow geese (Chen caerulescens caerulescens) and domesticated Japanese quail (Coturnix japonica). Formation of hydroxy-metabolites was analyzed using an ultra-high performance liquid chromatography-tandem mass spectrometry-based method. Incubation of BDE-47 with avian liver microsomes produced sixteen hydroxy-metabolites, eight of which were identified using authentic standards. The major metabolites formed by liver microsomes from individual lesser snow geese were 4-hydroxy-2,2',3,4'-tetrabromodiphenyl ether (4-OH-BDE-42), 3-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (3-OH-BDE-47), and 4'-hydroxy-2,2',4,5'-tetrabromodiphenyl ether (4'-OH-BDE-49). By comparison, 4-OH-BDE-42 and 4'-OH-BDE-49, but not 3-OH-BDE-47, were major metabolites of Japanese quail liver microsomes. Unidentified metabolites included monohydroxy- and dihydroxy-tetrabromodiphenyl ethers. Incubation of BDE-99 with avian liver microsomes produced seventeen hydroxy-metabolites, twelve of which were identified using authentic standards. The major metabolites formed by lesser snow goose liver microsomes were 2,4,5-tribromophenol, 3-OH-BDE-47, 4'-OH-BDE-49, 4-hydroxy-2,2',3,4',5-pentabromodiphenyl ether (4-OH-BDE-90), and 5'-hydroxy-2,2',4,4',5-pentabromodiphenyl ether (5'-OH-BDE-99). By comparison, the major metabolites produced by liver microsomes from Japanese quail included 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE-47) and 2-hydroxy-2',3,4,4',5-pentabromodiphenyl ether (2-OH-BDE-123), but not 3-OH-BDE-47. Unidentified metabolites consisted of monohydroxy-pentabromodiphenyl ethers, monohydroxy-tetrabromodiphenyl ethers and dihydroxy-tetrabromodiphenyl ethers. Another difference between the two species was that formation rates of BDE-47 and BDE-99 metabolites were greater with liver microsomes from male than female Japanese quail, but a sex difference was not observed with lesser snow geese. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dielectric and physiochemical study of binary mixture of nitrobenzene with toluene

NASA Astrophysics Data System (ADS)

Mohod, Ajay G.; Deshmukh, S. D.; Pattebahadur, K. L.; Undre, P. B.; Patil, S. S.; Khirade, P. W.

2018-05-01

This paper presents the study of binary mixture of Nitrobenzene (NB) with Toluene (TOL) for eleven different concentrations at room temperature. The determined Dielectric Constant (ɛ0) Density (ρ) and Refractive index (nD) values of binary mixture are used to calculate the excess properties i.e. Excess Dielectric Constant (ɛ0E), Excess Molar Volume (VmE), Excess Refractive Index (nDE) and Excess Molar Refraction (RmE) of mixture over the entire composition range and fitted to the Redlich-Kister equation. The Kirkwood Correlation Factor (geff) and other parameters were used to discuss the information about the orientation of dipoles and the solute-solvent interaction of binary mixture at molecular level over the entire range of concentration.

Finishing Systems for Naval Aircraft Applications: Current Schemes and Future Trends

DTIC Science & Technology

2000-01-01

glycidyl ether (CGE) and the difunctional neopentyl glycol , diglycidyl ether (NGDE) are pictured below in Figure 7. 16 o r CH3 OH CH2- XCH-CH2--0-<Q)-C...glycidyl ether (CGE) and neopentyl glycol , diglycidyl ether (NGDE). Coatings prepared with CGE were unacceptable due to poor surface properties and

Thermoset epoxy polymers from renewable resources

DOEpatents

East, Anthony [Madison, NJ; Jaffe, Michael [Maplewood, NJ; Zhang, Yi [Harrison, NJ; Catalani, Luiz H [Carapicuiba, BR

2009-11-17

Novel thermoset epoxy polymers using the bisglycidyl ethers of anhydrosugars, such as isosorbide, isomannide, and isoidide, are disclosed. The bisglycidyl ethers are useful as substitutes for bisphenol A in the manufacture of thermoset epoxy ethers. The anhydrosugars are derived from renewable sources and the bisglycidyl ethers are not xenoestrogenic and the thermoset curing agents are likewise derived form renewable resources.

IRIS Health Assessment of 2,2',4,4'-Tetrabromodiphenyl Ether (BDE-47) CASRN 5436-43-12,2',4,4',5-Pentabromodiphenyl Ether (BDE-99) CASRN 60348-60-92,2',4,4',5,5'-Hexabromodiphenyl Ether (BDE-153) CASRN 68631-49-22,2',3,3',4,4',5,5',6,6'-Decabromodiphenyl Ether (BDE-209) CASRN 1163-19-5

EPA Science Inventory

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in furniture foam (pentaBDE), plastics for TV cabinets, consumer electronics, wire insulation, and backcoatings for draperies and upholstery (decaBDE), and plastics for personal computers and small appliances (oc...

Functionalized poly(arylene ethers) as toughness modifiers for bismaleimides

NASA Technical Reports Server (NTRS)

Stenzenberger, H. D.; Roemer, W.; Hergenrother, P. M.; Jensen, B.; Breitigam, W.

1990-01-01

A family of novel, low molecular weight functionalized poly(arylene ether) resins has been investigated to ascertain its members' toughness-imparting contribution to neat bismaleimide (BMI) resin and BMI-matrix laminate composite properties. Attention is given to the contribution of the reactive poly(arylene ether)'s backbone chemistry to fracture toughness, as well as to the comparative influence of high and low molecular weight reactive poly(arylene ether) types on the modified BMI resin systems. The modified BMIs possess a polyphase morphology, with good adhesion between the thermoplastic nodules and the host thermoset systems.

Composition and process for separating cesium ions from an acidic aqueous solution also containing other ions

DOEpatents

Dietz, Mark L.; Horwitz, E. Philip; Bartsch, Richard A.; Barrans, Jr., Richard E.; Rausch, David

1999-01-01

A crown ether cesium ion extractant is disclosed as is its synthesis. The crown ether cesium ion extractant is useful for the selective purification of cesium ions from aqueous acidic media, and more particularly useful for the isolation of radioactive cesium-137 from nuclear waste streams. Processes for isolating cesium ions from aqueous acidic media using the crown ether cesium extractant are disclosed as are processes for recycling the crown ether cesium extractant and processes for recovering cesium from a crown ether cesium extractant solution.

Composition and process for separating cesium ions from an acidic aqueous solution also containing other ions

DOEpatents

Dietz, M.L.; Horwitz, E.P.; Bartsch, R.A.; Barrans, R.E. Jr.; Rausch, D.

1999-03-30

A crown ether cesium ion extractant is disclosed as is its synthesis. The crown ether cesium ion extractant is useful for the selective purification of cesium ions from aqueous acidic media, and more particularly useful for the isolation of radioactive cesium-137 from nuclear waste streams. Processes for isolating cesium ions from aqueous acidic media using the crown ether cesium extractant are disclosed as are processes for recycling the crown ether cesium extractant and processes for recovering cesium from a crown ether cesium extractant solution. 4 figs.