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Sample records for methyl tert butyl

  1. Methyl tert-butyl ether (MTBE)

    Integrated Risk Information System (IRIS)

    Methyl tert - butyl ether ( MTBE ) ; CASRN 1634 - 04 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments f

  2. Environmental Microbiology (2001) 3(6), 407416 Methyl tert-butyl ether (MTBE) degradation by a

    E-print Network

    2001-01-01

    Environmental Microbiology (2001) 3(6), 407±416 Methyl tert-butyl ether (MTBE) degradation of California, Riverside, Riverside, CA 92521, USA. Summary The widespread use of methyl tert-butyl ether (MTBE to add oxygenate to non-attainment areas. Methyl tert-butyl ether (MTBE) is the most used oxyge- nate

  3. 2-Benzhydryl-6-tert-butyl-4-methyl-phenol.

    PubMed

    Yoon, Sungwoo; Lee, Junseong; Kim, Youngjo

    2013-02-01

    The title compound, C(24)H(26)O, was prepared by the reaction between 2-tert-butyl-4-methyl-phenol and diphenyl-methanol in the presence of sulfuric acid. Three benzene rings are attached directly to the central C-H group in a twisted propeller conformation with the local pseudo-C(3) rotational axis coinciding with the C-H bond. There are three short C-H?O contacts in the molecule. PMID:23424558

  4. 2-Benzhydryl-6-tert-butyl-4-methyl­phenol

    PubMed Central

    Yoon, Sungwoo; Lee, Junseong; Kim, Youngjo

    2013-01-01

    The title compound, C24H26O, was prepared by the reaction between 2-tert-butyl-4-methyl­phenol and diphenyl­methanol in the presence of sulfuric acid. Three benzene rings are attached directly to the central C—H group in a twisted propeller conformation with the local pseudo-C 3 rotational axis coinciding with the C—H bond. There are three short C—H?O contacts in the molecule. PMID:23424558

  5. Microbial degradation of methyl tert-butyl ether and tert-butyl alcohol in the subsurface

    NASA Astrophysics Data System (ADS)

    Schmidt, Torsten C.; Schirmer, Mario; Weiß, Holger; Haderlein, Stefan B.

    2004-06-01

    The fate of fuel oxygenates such as methyl tert-butyl ether (MTBE) in the subsurface is governed by their degradability under various redox conditions. The key intermediate in degradation of MTBE and ethyl tert-butyl ether (ETBE) is tert-butyl alcohol (TBA) which was often found as accumulating intermediate or dead-end product in lab studies using microcosms or isolated cell suspensions. This review discusses in detail the thermodynamics of the degradation processes utilizing various terminal electron acceptors, and the aerobic degradation pathways of MTBE and TBA. It summarizes the present knowledge on MTBE and TBA degradation gained from either microcosm or pure culture studies and emphasizes the potential of compound-specific isotope analysis (CSIA) for identification and quantification of degradation processes of slowly biodegradable pollutants such as MTBE and TBA. Microcosm studies demonstrated that MTBE and TBA may be biodegradable under oxic and nearly all anoxic conditions, although results of various studies are often contradictory, which suggests that site-specific conditions are important parameters. So far, TBA degradation has not been shown under methanogenic conditions and it is currently widely accepted that TBA is a recalcitrant dead-end product of MTBE under these conditions. Reliable in situ degradation rates for MTBE and TBA under various geochemical conditions are not yet available. Furthermore, degradation pathways under anoxic conditions have not yet been elucidated. All pure cultures capable of MTBE or TBA degradation isolated so far use oxygen as terminal electron acceptor. In general, compared with hydrocarbons present in gasoline, fuel oxygenates biodegrade much slower, if at all. The presence of MTBE and related compounds in groundwater therefore frequently limits the use of in situ biodegradation as remediation option at gasoline-contaminated sites. Though degradation of MTBE and TBA in field studies has been reported under oxic conditions, there is hardly any evidence of substantial degradation in the absence of oxygen. The increasing availability of field data from CSIA will foster our understanding and may even allow the quantification of degradation of these recalcitrant compounds. Such information will help to elucidate the crucial factors of site-specific biogeochemical conditions that govern the capability of intrinsic oxygenate degradation.

  6. REDUCTIVE ACTIVATION OF DIOXYGEN FOR DEGRADATION OF METHYL TERT-BUTYL ETHER BY BIFUNCTION

    EPA Science Inventory

    Bifunctional aluminum is prepared by sulfating aluminum metal with sulfuric acid. The use of bifunctional aluminum to degrade methyl tert-butyl ether (MTBE) in the presence of dioxygen has been examined using batch systems. Primary degradation products were tert-butyl alcohol, ...

  7. INFLUENCE OF METHYL TERT-BUTYL ETHER (MTBE) ON LAKE WATER ALGAE: JOURNAL ARTICLE

    EPA Science Inventory

    NRMRL-ADA-01209 Kampbell*, D.H., An, Y, and Williams, VR. Influence of Methyl tert-Butyl Ether (MTBE) on Lake Water Algae. Bulletin of Environmental Contamination and Toxicology 57 (4):675-681 (2001). ...

  8. Selection and identification of bacterial strains with methyl-tert-butyl ether, ethyl-tert-butyl ether, and tert-amyl methyl ether degrading capacities.

    PubMed

    Purswani, Jessica; Pozo, Clementina; Rodríguez-Díaz, Marina; González-López, Jesús

    2008-11-01

    Nine bacterial strains isolated from two hydrocarbon-contaminated soils were selected because of their capacity for growth in culture media amended with 200 mg/L of one of the following gasoline oxygenates: Methyl-tert-butyl ether (MTBE), ethyl-tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). These strains were identified by amplification of their 16S rRNA gene, using fDl and rD1 primers, and were tested for their capacity to grow and biotransform these oxygenates in both mineral and cometabolic media. The isolates were classified as Bacillus simplex, Bacillus drentensis, Arthrobacter sp., Acinetobacter calcoaceticus, Acinetobacter sp., Gordonia amicalis (two strains), Nocardioides sp., and Rhodococcus ruber. Arthrobacter sp. (strain MG) and A. calcoaceticus (strain M10) consumed 100 (cometabolic medium) and 82 mg/L (mineral medium) of oxygenate TAME in 21 d, respectively, under aerobic conditions. Rhodococcus ruber (strain E10) was observed to use MTBE and ETBE as the sole carbon and energy source, whereas G. amicalis (strain T3) used TAME as the sole carbon and energy source for growth. All the bacterial strains transformed oxygenates better in the presence of an alternative carbon source (ethanol) with the exception of A. calcoaceticus (strain M10). The capacity of the selected strains to remove MTBE, ETBE, and TAME looks promising for application in bioremediation technologies. PMID:18522454

  9. Method for determination of methyl tert-butyl ether and its degradation products in water

    USGS Publications Warehouse

    Church, C.D.; Isabelle, L.M.; Pankow, J.F.; Rose, D.L.; Tratnyek, P.G.

    1997-01-01

    An analytical method is described that can detect the major alkyl ether compounds that are used as gasoline oxygenates (methyl tert-butyl ether, MTBE; ethyl tert-butyl ether, ETBE; and tert-amyl methyl ether, TAME) and their most characteristic degradation products (tert-butyl alcohol, TBA; tert-butyl formate, TBF; and tert-amyl alcohol, TAA) in water at sub-ppb concentrations. The new method involves gas chromatography (GC) with direct aqueous injection (DAI) onto a polar column via a splitless injector, coupled with detection by mass spectrometry (MS). DAI-GC/MS gives excellent agreement with conventional purge-and-trap methods for MTBE over a wide range of environmentally relevant concentrations. The new method can also give simultaneous identification of polar compounds that might occur as degradation products of gasoline oxygenates, such as TBA, TBF, TAA, methyl acetate, and acetone. When the method was applied to effluent from a column microcosm prepared with core material from an urban site in New Jersey, conversion of MTBE to TBA was observed after a lag period of 35 days. However, to date, analyses of water samples from six field sites using the DAI-GC/MS method have not produced evidence for the expected products of in situ degradation of MTBE.An analytical method is described that can detect the major alkyl ether compounds that are used as gasoline oxygenates (methyl tert-butyl ether, MTBE; ethyl tert-butyl ether, ETBE; and tert-amyl methyl ether, TAME) and their most characteristic degradation products (tert-butyl alcohol, TBA; tert-butyl formate, TBF; and tert-amyl alcohol, TAA) in water at sub-ppb concentrations. The new method involves gas chromatography (GC) with direct aqueous injection (DAI) onto a polar column via a splitless injector, coupled with detection by mass spectrometry (MS). DAI-GC/MS gives excellent agreement with conventional purge-and-trap methods for MTBE over a wide range of environmentally relevant concentrations. The new method can also give simultaneous identification of polar compounds that might occur as degradation products of gasoline oxygenates, such as TBA, TBF, TAA, methyl acetate, and acetone. When the method was applied to effluent from a column microcosm prepared with core material from an urban site in New Jersey, conversion of MTBE to TBA was observed after a lag period of 35 days. However, to date, analyses of water samples from six field sites using the DAI-GC/MS method have not produced evidence for the expected products of in situ degradation of MTBE.

  10. Accurate Computer Simulation of Phase Equilibrium for Complex Fluid Mixtures. Application to Binaries Involving Isobutene, Methanol, Methyl tert-Butyl Ether, and

    E-print Network

    Lisal, Martin

    to Binaries Involving Isobutene, Methanol, Methyl tert-Butyl Ether, and n-Butane Martin Li´sal,*,, William R + methyl tert-butyl ether (MTBE) and the binaries formed by methanol with isobutene, MTBE, and n

  11. IDENTIFYING THE USAGE PATTERNS OF METHYL TERT-BUTYL ETHER (MTBE) AND OTHER OXYGENATES IN GASOLINE USING GASOLINE

    E-print Network

    IDENTIFYING THE USAGE PATTERNS OF METHYL TERT-BUTYL ETHER (MTBE) AND OTHER OXYGENATES IN GASOLINE USING GASOLINE SURVEYS By Michael J. Moran, Rick M. Clawges, and John S. Zogorski U.S. Geological Survey 1608 Mt. View Rapid City, SD 57702 Methyl tert-butyl ether (MTBE) is commonly added to gasoline

  12. The antioxidant methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

    PubMed

    Li, Xiang; Wang, Zhi-Gang; Chen, Hou-He; Liu, Sheng-Gao

    2014-11-01

    The title compound, C18H28O3, was prepared by the reaction of 2,6-di-tert-butylphenol with methyl acrylate under basic conditions using dimethyl sulfoxide as the promoter. The structure of this antioxidant indicates significant strain between the ortho tert-butyl substituents and the phenolic OH group. In spite of the steric crowding of the OH group, it participates in intermolecular hydrogen bonding with the ester carbonyl O atom. PMID:25370105

  13. STRUCTURES AND BINDING ENERGIES OF METHYL TERT-BUTYL ETHER-WATER COMPLEXES

    EPA Science Inventory

    Methyl tert-butyl ether (MTBE) is a well-known environmental contaminant owing to its high solubility in water. Since the early 1990s, MTBE has been added to gasoline to improve air quality in some metropolitan areas of the United States. Improved air quality was, however, achiev...

  14. ATTENUATION OF METHYL TERT-BUTYL ETHER IN WATER USING SUNLIGHT AND A PHOTOCATALYST

    EPA Science Inventory

    The use of methyl tert-butyl ether (MTBE) as a gasoline additive has resulted in increasing pollution of ground water. Most of the conventional treatment technologies are inefficient or costly when the initial concentration of MTBE is low (<200 ug/L). In order to find an eco-frie...

  15. ATTENUATION OF METHYL TERT-BUTYL ETHER IN WATER USING SUNLIGHT AND A PHOTOCATALYST: JOURNAL ARTICLE

    EPA Science Inventory

    NRMRL-CIN-1535 Sahle-Demessie*, E., Enriquez*, J., and Gupta, G. Attenuation of Methyl tert-Butyl Ether in Water using Sunlight and a Photocatalyst. Water Environment Research (Virginia: Water Environment Federation) 74 (2):122-130 (2002). EPA/600/J-02/236. 07/19/2001 The use o...

  16. BIODEGRADATION OF METHYL TERT-BUTYL ETHER AND BTEX AT VARYING HYDRAULIC RETENTION TIMES

    EPA Science Inventory

    The feasibility of biologically degrading methyl tert-butyl ether (MTBE) contaminated groundwater is dependent on the ability to degrade MTBE and its byproducts in the presence of other gasoline contaminants. This study investigates a mixed culture degrading both MTBE and benzene...

  17. PHOTOCATALYTIC OXIDATION OF METHYL-TERT-BUTYL ETHER FOR DRINKING WATER TREATMENT

    EPA Science Inventory

    The photo-oxidation of methyl tert-butyl ether (MTBE) in water was investigated to determine the feasibility of using photocatalysis for the treatment of MTBE-contaminated drinking water. The feasibility assessment was conducted using slurries of titanium dioxide in both a photo-...

  18. TREATMENT OF METHYL TERT-BUTYL ETHER CONTAMINATED WATER USING PHOTOCATALYSIS

    EPA Science Inventory

    The feasibility of photo-oxidation treatment of methyl tert-butyl ether (MTBE) in water was investigated in three ways, 1) using a slurry falling film photo-reactor, 2) a batch solar reactor system, and 3) a combination of air-stripping and gas phase photooxidation system. MTBE-c...

  19. BIODEGRADATION OF METHYL TERT-BUTYL ETHER USING AN INNOVATIVE BIOMASS CONCENTRATOR REACTOR

    EPA Science Inventory

    The aerobic biodegradation of methyl tert-butyl ether (MTBE) was investigated using a pilot-scale Biomass Concentrator Reactor (BCR). The reactor was operated for a year at a flow rate of 2500 L/d of Cincinnati dechlorinated tap water and an influent MTBE concentration o...

  20. INFLUENCE OF METHYL TERT-BUTYL ETHER (MTBE) ON LAKE WATER ALGAE

    EPA Science Inventory

    Methyl tert-butyl ether (MTBE) has been used as an octane booster in gasoline in the United States since the 1970s. MTBE use increased greatly in the 1990s with the implementation of the Clean Air Act Amendments of 1990. The MTBE enhanced a more complete combustion of fuel hydroc...

  1. INHALATION EXPOSURE TO METHYL TERT-BUTYL ETHER (MTBE) AND DIBROMOCHLOROMETHANE (DBCM) USING CONTINUOUS BREATH ANALYSIS

    EPA Science Inventory

    The oxygenate methyl tert-butyl ether (MTBE) has been added to gasoline to help meet national ambient air quality standards in those parts of the U.S. that are non-compliant for carbon monoxide. Although MTBE has provided important health benefits in terms of reduced haza...

  2. Identification of mercury methylation product by tert-butyl compounds in aqueous solution under light irradiation.

    PubMed

    Chen, Baowei; Chen, Ping; He, Bin; Yin, Yongguang; Fang, Linchuan; Wang, Xiaowei; Liu, Hongtao; Yang, Lihua; Luan, Tiangang

    2015-09-15

    The methylation of mercury (Hg) is of great concern as methylmercury (MeHg), the most toxic species, is produced. This study examined the possibilities of tert-butyl compounds (tert-butyl alcohol (TBA) and tert-butyl hydroperoxide (TBH)) and other alcohols serving as methyl donors for Hg photo-methylation under light irradiation. The yield of MeHg varied among the methyl donors, and it was also significantly influenced by salinity and pH. MeHg could be generated in the presence of TBH under visible light irradiation. The hydroxyl radical (OH) was found to promote MeHg production at low levels, but degrade MeHg in excess. The photo-production of MeHg was tentatively proposed via the complexation of Hg and methyl donors, the formation of an intermediate (O(Hg)C(CH3)3), and the intramolecular methyl transfer from methyl donors to Hg. This study implicates photoreactions between Hg and organic pollutants in understanding the fate and transformation of Hg in the aquatic environment. PMID:26165936

  3. 2,6-Di-tert-butyl-4-[(N-methyl-anilino)meth-yl]phenol.

    PubMed

    Zeng, Tao; Sun, Ju-Feng

    2008-01-01

    The title compound, C(22)H(31)NO, has been synthesized from 4-bromo-methyl-2,6-di-tert-butyl-phenol and N-methyl-aniline. There are two independent mol-ecules in the asymmetric unit. The aniline ring in each of the independent mol-ecules was found to be disordered, with site occupation factors 0.621?(10)/0.379?(10) and 0.605?(10)/0.395?(10). PMID:21201438

  4. 2,6-Di-tert-butyl-4-[(N-methyl­anilino)meth­yl]phenol

    PubMed Central

    Zeng, Tao; Sun, Ju-Feng

    2008-01-01

    The title compound, C22H31NO, has been synthesized from 4-bromo­methyl-2,6-di-tert-butyl­phenol and N-methyl­aniline. There are two independent mol­ecules in the asymmetric unit. The aniline ring in each of the independent mol­ecules was found to be disordered, with site occupation factors 0.621?(10)/0.379?(10) and 0.605?(10)/0.395?(10). PMID:21201438

  5. Oxidation of methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE) by ozone and combined ozone/hydrogen peroxide

    SciTech Connect

    Leitner, N.K.V.; Papailhou, A.L.; Croue, J.P.; Dore, M. ); Peyrot, J. )

    1994-01-01

    The aim of this work was to study the reaction of ozone and combined ozone/hydrogen peroxide on oxygenated additives such as methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE) in dilute aqueous solution using controlled experimental conditions. Experiments conducted in a semi-continuous reactor with MTBE and ETBE in combination (initial concentration: 2 mmol/L of each) showed that ETBE was better eliminated than MTBE with both ozone and combined O[sub 3]/H[sub 2]O[sub 2]. batch experiments led to the determination of the ratio of the kinetic constants for the reaction of OH[degree]-radical with MTBE and ETBE (k[sub OH[degree]/ETBE]/k[sub OH[degree]//MTBE] = 1.7). Tert-butyl formate and tert-butyl acetate were identified as the ozonation byproducts of MTBE an ETBE, respectively, while tert-butyl alcohol was found to be produced during the ozonation of both compounds. 10 refs., 10 figs., 1 tab.

  6. WATER QUALITY AT FIVE MARINAS IN LAKE TEXOMA AS RELATED TO METHYL TERT-BUTYL ETHER (MTBE): JOURNAL ARTICLE

    EPA Science Inventory

    NRMRL-ADA- 02224 An, Y, Kampbell*, D.H., and Sewell*, G.W. WATER QUALITY AT FIVE MARINAS IN LAKE TEXOMA AS RELATED TO METHYL TERT-BUTYL ETHER (MTBE). Environmental Pollution118: 331-336 (2002). 600/J-02/230. Occurrence of methyl tert-but...

  7. Biotransformation of methyl tert-butyl ether by human cytochrome P450 2A6.

    PubMed

    Shamsipur, Mojtaba; Miran Beigi, Ali Akbar; Teymouri, Mohammad; Poursaberi, Tahereh; Mostafavi, S Mojtaba; Soleimani, Parviz; Chitsazian, Fereshteh; Tash, Shahram Abolhassan

    2012-04-01

    Methyl tert-butyl ether (MTBE) is widely used as gasoline oxygenate and octane number enhancer for more complete combustion in order to reduce the air pollution caused by motor vehicle exhaust. The possible adverse effects of MTBE on human health are of major public concern. However, information on the metabolism of MTBE in human tissues is scarce. The present study demonstrates that human cytochrome P450 2A6 is able to metabolize MTBE to tert-butyl alcohol (TBA), a major circulating metabolite and marker for exposure to MTBE. As CYP2A6 is known to be constitutively expressed in human livers, we infer that it may play a significant role in metabolism of gasoline ethers in liver tissue. PMID:21915685

  8. Decreased toxicity to terrestrial plants associated with a mixture of methyl tert-butyl ether and its metabolite tert-butyl alcohol.

    PubMed

    An, Youn-Joo; Lee, Woo-Mi

    2007-08-01

    The influence of the main fuel oxygenate methyl tert-butyl ether (MTBE) and its key metabolite, tert-butyl alcohol (TBA), on the growth of a plant seedling was studied separately and in combination. The test plants were mung bean (Phaseolus radiatus), cucumber (Cucumis sativus), wheat (Triticum aestivum), sorghum (Sorghum bicolor), kale (Brassica alboglabra), Chinese cabbage (Brassica campestris), and sweet corn (Zea mays). The growth of all the plants was adversely affected by TBA and MTBE. The 5-d median effective concentration (EC50) for the plants exposed to MTBE and TBA were in the range of 680 to 1,000 mg MTBE/kg soil (dry wt) and 1,200 to 3,500 mg TBA/kg soil (dry wt), respectively. The relative order of the sensitivity rankings is almost the same for MTBE and TBA. Methyl tert-butyl ether is more toxic than TBA to most of the test species. Based on the EC50 values, MTBE is approximately 1.5 to 3 times more potent than TBA. The sum of the toxic unit (TU) at 50% inhibition of the mixture (EC50mix) was calculated from the dose (TU-based)-response relationships using the trimmed Spearman-Karber method. The combined effect of MTBE + TBA on the plant growth was less than additive because the EC50mix values were greater than I TU. This phenomenon may be due to the competition of MTBE and TBA in terms of their intake by plants. The combined effects of MTBE and TBA should be taken into account to assess their risk in gasoline-contaminated sites. PMID:17702346

  9. INTERACTION OF METHYL-TERT BUTYL ETHER AND WATER STRESS ON SEED GERMINATION AND SEEDLING GROWTH IN SOIL MICROCOSMS

    EPA Science Inventory

    Methyl tert-butyl ether (MTBE) is a widespread contaminant in surface and ground water in the United States. Frequently irrigation is used to water fields to germinate planted seeds and sustain plant growth. A likely possibility exists that water used may have some MTBE. Our s...

  10. EVALUATION OF METHYL TERT-BUTYL ETHER (MTBE) AS AN INTERFERENCE ON COMMERCIAL BREATH-ALCOHOL ANALYZERS

    EPA Science Inventory

    Anecdotal reports suggest that high environmental or occupational exposures to the fuel oxygenate methyl tert-butyl ether (MTBE) may result in breath concentrations that are sufficiently elevated to cause a false positive on commercial breath-alcohol analyzers. We evaluated th...

  11. DERMAL EXPOSURE TO METHYL TERT-BUTYL ETHER (MTBE) AND DIBROMOCHLOROMETHANE (DBCM) WHILE BATHING WITH CONTAMINATED WATER

    EPA Science Inventory

    The oxygenate methyl tert-butyl ether (MTBE) has been added to gasoline to help meet national ambient air quality standards in those parts of the U.S. that are non-compliant for carbon monoxide. Although MTBE has provided important health benefits in terms of reduced hazardous a...

  12. Anaerobic Biodegradation Of Methyl tert-Butyl Ether Under Iron-Reducing Conditions In Batch And Continuous-Flow Cultures

    EPA Science Inventory

    The feasibility of biodegradation of the fuel oxygenate methyl tert-butyl ether (MTBE) under iron-reducing conditions was explored in batch and continuous-flow systems. A porous pot completely-mixed reactor was seeded with diverse cultures and operated under iron-reducing...

  13. WATER QUALITY AT FIVE MARINAS IN LAKE TEXOMA AS RELATED TO METHYL TERT-BUTYL ETHER (MTBE)

    EPA Science Inventory

    Occurrence of methyl tert-butyl ether (MTBE) in five marinas was monitored between June 1999 and November 2000 in Lake Texoma located on the border of Oklahoma and Texas. MTBE is a commonly used gasoline additive and a suspected carcinogen. Lake water was collected at locations i...

  14. CO-OCCURRENCE OF METHYL- TERT-BUTYL ETHER (MTBE) AND BTEX COMPOUNDS AT MARINAS IN A LARGE RESEVOIR

    EPA Science Inventory

    Methyl tert-butyl ether (MTBE) is released into the environment as one of some gasoline components, not as a pure compound. BTEX compounds (benzene, tolune, ethylbenzene, and xylenes) are major volatile constituents found in gasoline and are water soluble and mobile. This study...

  15. Removal of Methyl-tert-butyl Ether from Water by a Pulsed Arc Electrohydraulic Discharge System

    NASA Astrophysics Data System (ADS)

    Angeloni, Danielle M.; Dickson, Sarah E.; Emelko, Monica B.; Chang, Jen-Shih

    2006-10-01

    The removal of methyl-tert-butyl ether (MTBE) from water by a pulsed arc electrohydraulic discharge (PAED) system was investigated experimentally at the laboratory scale. The effects of arc electrode gap, detention time and initial solution pH on the efficacy of MTBE treatment by PAED were investigated. A 0.3 kJ/pulse spark-gap-type power supply was employed in combination with a 3.0 L flow-through reactor. Experimental results showed that: 1) oxidation reactions are induced by this PAED system; 2) removal efficiency increases with increasing cumulative input energy (kW\\cdoth/m3 or kJ/L); 3) removal efficiency decreases with increasing arc electrode gap; and 4) initial solution pH does not have a significant effect on the efficacy of MTBE removal by PAED when the water matrix is buffered prior to treatment.

  16. Methyl tert butyl ether targets developing vasculature in zebrafish (Danio rerio) embryos.

    PubMed

    Bonventre, Josephine A; White, Lori A; Cooper, Keith R

    2011-09-01

    Disruption of vascular endothelial growth factor (VEGF) signaling during early development results in abnormal angiogenesis and increased vascular lesions. Embryonic exposure to 0.625-10mM methyl tert butyl ether (MTBE), a highly water soluble gasoline additive, resulted in a dose dependent increase in pooled blood in the common cardinal vein (CCV), cranial hemorrhages and abnormal intersegmental vessels (ISVs). The EC50s for the lesions ranked in terms of likelihood to occur with MTBE exposure were: pooled blood in the CCV, 3.2 mM [95% CI: 2.2-4.7]>cranial hemorrhage, 11 mM [5.9-20.5]>abnormal ISV, 14.5 mM [6.5-32.4]. Organ systems other than the vascular system appear to develop normally, which suggests MTBE toxicity targets developing blood vessels. Equal molar concentrations (0.625-10mM) of the primary metabolites, tertiary butyl alcohol (TBA) and formaldehyde, did not result in vascular lesions, which suggested that the parent compound is responsible for the toxicity. Stage specific exposures were carried out to determine the developmental period most sensitive to MTBE vascular disruption. Embryos treated until 6-somites or treated after Prim-5 stages did not exhibit a significant increase in lesions, while embryos treated between 6-somites and Prim-5 had a significant increase in vascular lesions (p?0.05). During the critical window for MTBE-induced vascular toxicity, expression of vegfa, vegfc, and flk1/kdr were significantly decreased 50, 70 and 40%, respectively. This is the first study to characterize disruption in vascular development following embryonic exposure to MTBE. The unique specificity of MTBE to disrupt angiogenesis may be mediated by the down regulation of critical genes in the VEGF pathway. PMID:21684239

  17. Methyl tert butyl ether targets developing vasculature in zebrafish (Danio rerio) embryos

    PubMed Central

    Bonventre, Josephine A.; White, Lori A.; Cooper, Keith R.

    2015-01-01

    Disruption of vascular endothelial growth factor (VEGF) signaling during early development results in abnormal angiogenesis and increased vascular lesions. Embryonic exposure to 0.625 to 10 mM methyl tert butyl ether (MTBE), a highly water soluble gasoline additive, resulted in a dose dependent increase in pooled blood in the common cardinal vein (CCV), cranial hemorrhages and abnormal intersegmental vessels (ISVs). The EC50s for the lesions ranked in terms of likelihood to occur with MTBE exposure were: pooled blood in the CCV, 3.2 mM [95 % CI: 2.2 – 4.7] > cranial hemorrhage, 11 mM [5.9 – 20.5] > abnormal ISV, 14.5 mM [6.5 – 32.4]. Organ systems other than the vascular system appear to develop normally, which suggests MTBE toxicity targets developing blood vessels. Equal molar concentrations (0.625 to 10 mM) of the primary metabolites, tertiary butyl alcohol (TBA) and formaldehyde, did not result in vascular lesions, which suggested that the parent compound is responsible for the toxicity. Stage specific exposures were carried out to determine the developmental period most sensitive to MTBE vascular disruption. Embryos treated until 6-somites or treated after Prim-5 stages did not exhibit a significant increase in lesions, while embryos treated between 6-somites and Prim-5 had a significant increase in vascular lesions (p ? 0.05). During the critical window for MTBE-induced vascular toxicity, expression of vegfa, vegfc, and flk1/kdr were significantly decreased 50, 70 and 40%, respectively. This is the first study to characterize disruption in vascular development following embryonic exposure to MTBE. The unique specificity of MTBE to disrupt angiogenesis may be mediated by the down regulation of critical genes in the VEGF pathway. PMID:21684239

  18. Reaction calorimetry study of the liquid-phase synthesis of tert-butyl methyl ether

    SciTech Connect

    Sola, L.; Pericas, M.A.; Cunill, F.; Iborra, M. . Dept. d'Enginyeria Quimica)

    1994-11-01

    The liquid-phase addition of methanol to isobutene to give tert-butyl methyl ether (MTBE) on the ion-exchange resin Lewatit K2631 has been studied in a calorimetric reactor. Heat capacity of MTBE and enthalpy of the MTBE synthesis reaction in the temperature range 312--333 K have been determined. MTBE heat capacity in the liquid phase has been found to obey the equation c[sub P] (J/mol[center dot]K) = 472.34 [minus] 2.468(T/K) + 0.005071(T/K)[sup 2]. At 298 K the standard molar reaction enthalpy is [Delta]H[degree] = [minus]33.8 kJ/mol. A method to estimate apparent activation energies from heat flow rate in a given reaction has been developed and proved to be valid for the MTBE synthesis. Using this method, an apparent activation energy of 91.1--95.2 kJ/mol is calculated. A [minus]3.8 kJ/mol value has been found for the adsorption enthalpy of methanol on the ion-exchange resin Lewatit K2631 by a combination of reaction calorimetry and thermogravimetry. This allows the calculation of an activation energy on the gel phase of the resin of 91 kJ/mol.

  19. Biomarkers of exposure to aromatic hydrocarbons and methyl tert-butyl ether in petrol station workers.

    PubMed

    De Palma, Giuseppe; Poli, Diana; Manini, Paola; Andreoli, Roberta; Mozzoni, Paola; Apostoli, Pietro; Mutti, Antonio

    2012-06-01

    This cross-sectional study was aimed at reconstructing the exposure to gasoline in 102 petrol station attendants by environmental and biological monitoring of benzene, toluene, ethylbenzene and xylene (BTEX) and biomonitoring of methyl tert-butyl ether (MTBE). Airborne BTEX were higher for manual refuelers than self-service assistants and were highly correlated with each other. Significant relationships were found between airborne BTX and the corresponding urinary solvents (U-BTX) and beween airborne B and urinary MTBE (U-MTBE). Smokers eliminated higher values of U-B, trans,trans-muconic (t,t-MA) and S-phenylmercapturic (S-PMA) acids but not U-MTBE. All these biomarkers were, however, significantly raised during the shift, independently from smoking. Linear regression confirmed that occupational exposure was a main predictor of U-MTBE, U-B and S-PMA values, both the latter confounded by smoking habits. The study supports the usefulness of biomonitoring even at low exposure levels. PMID:22458326

  20. Methyl tert-butyl ether biodegradation by indigenous aquifer microorganisms under natural and artificial oxic conditions

    USGS Publications Warehouse

    Landmeyer, J.E.; Chapelle, F.H.; Herlong, H.H.; Bradley, P.M.

    2001-01-01

    Microbial communities indigenous to a shallow groundwater system near Beaufort, SC, degraded milligram per liter concentrations of methyl tert-butyl ether (MTBE) under natural and artificial oxic conditions. Significant MTBE biodegradation was observed where anoxic, MTBE-contaminated groundwater discharged to a concrete-lined ditch. In the anoxic groundwater adjacent to the ditch, concentrations of MTBE were > 1 mg/L. Where groundwater discharge occurs, dissolved oxygen (DO) concentrations beneath the ditch exceeded 1.0 mg/L to a depth of 1.5 m, and MTBE concentrations decreased to <1 ??g/L prior to discharge. MTBE mass flux calculations indicate that 96% of MTBE mass loss occurs in the relatively small oxic zone prior to discharge. Samples of a natural microbial biofilm present in the oxic zone beneath the ditch completely degraded [U-14C]MTBE to [14C]CO2 in laboratory liquid culture studies, with no accumulation of intermediate compounds. Upgradient of the ditch in the anoxic, MTBE and BTEX-contaminated aquifer, addition of a soluble oxygen release compound resulted in oxic conditions and rapid MTBE biodegradation by indigenous microorganisms. In an observation well located closest to the oxygen addition area, DO concentrations increased from 0.4 to 12 mg/L in <60 days and MTBE concentrations decreased from 20 to 3 mg/L. In the same time period at a downgradient observation well, DO increased from <0.2 to 2 mg/L and MTBE concentrations decreased from 30 to <5 mg/L. These results indicate that microorganisms indigenous to the groundwater system at this site can degrade milligram per liter concentrations of MTBE under natural and artificial oxic conditions.

  1. Laboratory Method for Analysis of Small Concentrations of Methyl tert-Butyl Ether and Other Ether Gasoline Oxygenates in Water

    USGS Publications Warehouse

    Rose, Donna L.; Connor, Brooke F.; Abney, Sonja R.; Raese, Jon W.

    1998-01-01

    This Fact Sheet presents data for analysis of nanogram-per-liter concentrations of methyl tert-butyl ether (MTBE) and three other ether gasoline oxygenates, including methyl tert-pentyl ether (TAME), diisopropyl ether (DIPE), and ethyl tert-butyl ether (ETBE), by purge- and-trap capillary-column gas chromatography. Long-term method detection levels (LT-MDLs) for MTBE, TAME, DIPE, and ETBE ranged from 15 to 83 nanograms per liter (0.015 to 0.083 microgram per liter). Nanogram-per-liter-concentration detections are reported if all of the identification criteria are met, whereas previous methods censored detections at a pre-determined method reporting level. The reporting level for this method is defined as two times the LT-MDL, does not censor detections at less than this concentration, and is referred to as the nondetection value (NDV). Bias and variability data from multiple analyses, analysts, and instruments over a 60-day period show the oxygenate recoveries ranging from 100 to 109 percent, with 6 to 8 percent relative standard deviation. MTBE, TAME, DIPE, and ETBE were not detected in the analysis of 225 laboratory reagent blanks from January to December 1997. A preservation study in ground water and surface water indicates that all the oxygenates are stable at pH 2 for up to 216 days, with recoveries ranging from 94 to 115 percent on day 216, and relative standard deviations ranging from 5 to 9 percent for the duration of the study.

  2. Treatment of Methyl tert-Butyl Ether Contaminated Water Using a Dense

    E-print Network

    Dandy, David

    of aqueous organic pollutants. This study examines the kinetic and oxidation mechanisms of methyl tert treatment method if complete oxidation can be achieved, or at the very least if the pollutant compounds can been concentrated in groundwater through leaks in underground storage tanks and gasoline spills

  3. Crystal structure of 4-azido­methyl-6-tert-butyl-2H-chromen-2-one

    PubMed Central

    El-Khatatneh, Nasseem; Chandra; Shamala, D.; Shivashankar, K.; Panzi, Mukhokosi Emma; Mahendra, M.

    2015-01-01

    In the title compound, C14H15N3O2, one of the methyl C atoms of the tert-butyl group lies almost in the plane of the chromene ring system [deviation = ?0.097?(2)?Å], one lies above and one lies below [deviations = 1.460?(3) and 1.006?(3)?Å, respectively]. The C—C—N—N torsion angle is 142.33?(17)°. In the crystal, moelcules are linked by weak C—H?O hydrogen bonds to generate C(6) chains propagating in the [010] direction. PMID:26029422

  4. Crystal structure of 4-azido-methyl-6-tert-butyl-2H-chromen-2-one.

    PubMed

    El-Khatatneh, Nasseem; Chandra; Shamala, D; Shivashankar, K; Panzi, Mukhokosi Emma; Mahendra, M

    2015-04-01

    In the title compound, C14H15N3O2, one of the methyl C atoms of the tert-butyl group lies almost in the plane of the chromene ring system [deviation = -0.097?(2)?Å], one lies above and one lies below [deviations = 1.460?(3) and 1.006?(3)?Å, respectively]. The C-C-N-N torsion angle is 142.33?(17)°. In the crystal, moelcules are linked by weak C-H?O hydrogen bonds to generate C(6) chains propagating in the [010] direction. PMID:26029422

  5. Bis[?-N-(tert-butyl­dimethyl­silyl)-N-(pyridin-2-ylmeth­yl)amido]­bis­[methyl­cobalt(II)

    PubMed Central

    Malassa, Astrid; Agthe, Christine; Görls, Helmar; Westerhausen, Matthias

    2012-01-01

    The green title complex, [Co2(CH3)2(C12H21N2Si)2], was obtained from bis­{[?-N-tert-butyl­dimethyl­silyl-N-(pyridin-2-ylmeth­yl)amido]­chloridocobalt(II)} and methyl­lithium in diethyl ether at 195?K via a metathesis reaction. The dimeric cobalt(II) complex exhibits a crystallographic center of inversion in the middle of the Co2N2 ring (average Co—N = 2.050?Å). The CoII atom shows a distorted tetra­hedral coordination sphere. The exocyclic Co—N bond length to the pyridyl group shows a similar value of 2.045?(4)?Å. The exocyclic methyl group has a rather long Co—C bond length of 2.019?(5)?Å. PMID:22969464

  6. Treatment of methyl tert-butyl ether contaminated water using a dense medium plasma reactor: a mechanistic and kinetic investigation.

    PubMed

    Johnson, Derek C; Shamamian, Vasgen A; Callahan, John H; Denes, Ferencz S; Manolache, Sorin O; Dandy, David S

    2003-10-15

    Plasma treatment of contaminated water appears to be a promising alternative for the oxidation of aqueous organic pollutants. This study examines the kinetic and oxidation mechanisms of methyl tert-butyl ether (MTBE) in a dense medium plasma (DMP) reactor utilizing gas chromatography-mass spectrometry and gas chromatography-thermal conductivity techniques. A rate law is developed for the removal of MTBE from an aqueous solution in the DMP reactor. Rate constants are also derived for three reactor configurations and two pin array spin rates. The oxidation products from the treatment of MTBE-contaminated water in the DMP reactor were found to be predominately carbon dioxide, with smaller amounts of acetone, tert-butyl formate, and formaldehyde. The lack of stable intermediate products suggests that the MTBE is, to some extent, oxidized directly to carbon dioxide, making the DMP reactor a promising tool in the future remediation of water. Chemical and physical mechanisms together with carbon balances are used to describe the formation of the oxidation products and the important aspects of the plasma discharge. PMID:14594395

  7. Methyl tert-butyl ether (MTBE) is a volatile organic com-pound (VOC) derived from natural gas that is added to gas-

    E-print Network

    Methyl tert-butyl ether (MTBE) is a volatile organic com- pound (VOC) derived from natural gas Water in Urban and Agricultural Areas made from methanol, which is derived primarily from natural gas that is added to gas- oline either seasonally or year round in many parts of the United States to increase

  8. Treatment Of Groundwater Contaminated With PAHs, Gasoline Hydrocarbons, And Methyl Tert-Butyl Ether In A Laboratory Biomass-Retaining Bioreactor

    EPA Science Inventory

    In this study, we investigated the treatability of co-mingled groundwater contaminated with polycyclic aromatic hydrocarbons (PAHs), gasoline hydrocarbons, and methyl tert-butyl ether (MtBE) using an ex-situ aerobic biotreatment system. The PAHs of interest were nap...

  9. A comparative study of biodiesel production using methanol, ethanol, and tert-butyl methyl ether (MTBE) under supercritical conditions.

    PubMed

    Farobie, Obie; Matsumura, Yukihiko

    2015-09-01

    In this study, biodiesel production under supercritical conditions among methanol, ethanol, and tert-butyl methyl ether (MTBE) was compared in order to elucidate the differences in their reaction behavior. A continuous reactor was employed, and experiments were conducted at various reaction temperatures (270-400 °C) and reaction times (3-30 min) and at a fixed pressure of 20 MPa and an oil-to-reactant molar ratio of 1:40. The results showed that under the same reaction conditions, the supercritical methanol method provided the highest yield of biodiesel. At 350 °C and 20 MPa, canola oil was completely converted to biodiesel after 10, 30, and 30 min in the case of - supercritical methanol, ethanol, and MTBE, respectively. The reaction kinetics of biodiesel production was also compared for supercritical methanol, ethanol, and MTBE. PMID:26004381

  10. Crystal structure of (1,3-di-tert-butyl-?5-cyclo­penta­dien­yl)tri­methyl­hafnium(IV)

    PubMed Central

    Pérez-Redondo, Adrián; Varela-Izquierdo, Víctor; Yélamos, Carlos

    2015-01-01

    The mol­ecule of the title organometallic hafnium(IV) com­pound, [Hf(CH3)3(C13H21)] or [HfMe3(?5-C5H3-1,3-tBu2)], adopts the classical three-legged piano-stool geometry for mono­cyclo­penta­dienylhafnium(IV) derivatives with the three methyl groups bonded to the Hf(IV) atom at the legs. The C atoms of the two tert-butyl group bonded to the cyclo­penta­dienyl (Cp) ring are 0.132?(5) and 0.154?(6)?Å above the Cp least-squares plane. There are no significant inter­molecular inter­actions present between the mol­ecules in the crystal structure. PMID:25995884

  11. Energy analysis for the production of biodiesel in a spiral reactor using supercritical tert-butyl methyl ether (MTBE).

    PubMed

    Farobie, Obie; Matsumura, Yukihiko

    2015-11-01

    In this study, energy analysis was conducted for the production of biodiesel in a spiral reactor using supercritical tert-butyl methyl ether (MTBE). This study aims to determine the net energy ratio (NER) and energy efficiency for the production of biodiesel using supercritical MTBE and to verify the effectiveness of the spiral reactor in terms of heat recovery efficiency. The analysis results revealed that the NER for this process was 0.92. Meanwhile, the energy efficiency was 0.98, indicating that the production of biodiesel in a spiral reactor using supercritical MTBE is an energy-efficient process. By comparing the energy supply required for biodiesel production between spiral and conventional reactors, the spiral reactor was more efficient than the conventional reactor. PMID:26231125

  12. Distribution of methyl tert-butyl ether (MTBE) and selected water-quality constituents in the surficial aquifer at the Dover National Test Site, Dover Air Force Base, Delaware, 2001

    USGS Publications Warehouse

    Stewart, Marie; Guertal, William R.; Barbaro, Jeffrey R.; McHale, Timothy J.

    2004-01-01

    A joint study by the Dover National Test Site, Dover Air Force Base, Delaware, and the U.S. Geological Survey was conducted from June 27 through July 18, 2001, to determine the spatial distribution of the gasoline oxygenate additive methyl tert-butyl ether and selected water-quality constituents in the surficial aquifer underlying the Dover National Test Site. This report provides a summary assessment of the distribution of methyl tert-butyl ether and a preliminary screening of selected constituents that may affect natural attenuation and remediation demonstrations at the Dover National Test Site. The information gathered during this study is designed to assist potential remedial investigators who are considering conducting a methyl tert-butyl ether remedial demonstration at the test site. In addition, the study supported a planned enhanced bioremediation demonstration and assisted the Dover National Test Site in identifying possible locations for future methyl tert-butyl ether remediation demonstrations. A direct-push drill rig was used to collect a total of 147 ground-water samples (115 VOC samples and 32 quality-assurance samples) at varying depths. Volatile organic compounds were above the method reporting limits in 59 of the 115 ground-water samples. The concentrations ranged from below detection limits to maximum values of 12.4 micrograms per liter of cis-1,2-dichloro-ethene, 1.14 micrograms per liter of trichloro-ethene, 2.65 micrograms per liter of tetrachloro-ethene, 1,070 micrograms per liter of methyl tert-butyl ether, 4.36 micrograms per liter of benzene, and 1.8 micrograms per liter of toluene. Vinyl chloride, ethylbenzene, p,m-xylene, and o-xylene were not detected in any of the samples collected during this investigation. Methyl tert-butyl ether was detected in 47 of the 115 ground-water samples. The highest concentrations of methyl tert-butyl ether were detected in the surficial aquifer from ?4.6 to 6.4 feet mean sea level; however, methyl tert-butyl ether was detected as deep as ?9.5 feet mean sea level. Increased methane concentrations and decreased dissolved oxygen concentrations that were found in association with the ground-water samples that contained methyl tert-butyl ether are preliminary indicators that will assist in determining if natural attenuation of methyl tert-butyl ether is occurring in the surficial aquifer. A full assessment of natural attenuation of methyl tert-butyl ether at the site is beyond the scope of this study, but the data collected during the study will be useful in selecting appropriate remedial methyl tert-butyl ether demonstrations.

  13. Anaerobic biodegradation of methyl tert-butyl ether under iron-reducing conditions in batch and continuous-flow cultures.

    PubMed

    Pruden, Amy; Sedran, Marie A; Suidan, Makram T; Venosa, Albert D

    2005-01-01

    The feasibility of biodegradation of the fuel oxygenate methyl tert-butyl ether (MTBE) under iron-reducing conditions was explored in batch and continuous-flow systems. A porous pot completely-mixed reactor was seeded with diverse cultures and operated under iron-reducing conditions. For batch studies, culture from the reactor was transferred anaerobically to serum bottles containing either MTBE alone or MTBE with ethanol (EtOH) and excess electron acceptor. In the continuous-flow reactor, MTBE conversion to tert-butyl alcohol (TBA) was observed after 181 days of operation, and stable removal was achieved throughout the remainder of the study. Simultaneously, both the MTBE only and the MTBE and EtOH iron-reducing batch serum bottles also began to degrade MTBE. Bottles were respiked and the degradation rate was determined to be 2.36 +/- 0.10 x 10(-4) mmol MTBE/min-kgVSS. The EtOH present with MTBE degraded faster (7.76 +/- 0.08 x 10(-3) mmol EtOH/min-kg VSS) but did not have a noticeable effect on the rate of MTBE degradation. No evidence of TBA degradation was observed by the iron-reducing cultures. Stoichiometry of iron utilization was determined from the iron balance of the continuous-flow reactor, and it was found that the bulk of the electron acceptor was required for energy and maintenance with little remaining for cell synthesis. This is consistent with a yield coefficient of less than 0.1. Molecular analysis of the iron-reducing culture by denaturing gradient gel electrophoresis indicated that uncultured strains of delta-Proteobacteria were dominant in the reactor. PMID:15969296

  14. Anaerobic Methyl tert-Butyl Ether-Degrading Microorganisms Identified in Wastewater Treatment Plant Samples by Stable Isotope Probing

    PubMed Central

    Sun, Weimin; Sun, Xiaoxu

    2012-01-01

    Anaerobic methyl tert-butyl ether (MTBE) degradation potential was investigated in samples from a range of sources. From these 22 experimental variations, only one source (from wastewater treatment plant samples) exhibited MTBE degradation. These microcosms were methanogenic and were subjected to DNA-based stable isotope probing (SIP) targeted to both bacteria and archaea to identify the putative MTBE degraders. For this purpose, DNA was extracted at two time points, subjected to ultracentrifugation, fractioning, and terminal restriction fragment length polymorphism (TRFLP). In addition, bacterial and archaeal 16S rRNA gene clone libraries were constructed. The SIP experiments indicated bacteria in the phyla Firmicutes (family Ruminococcaceae) and Alphaproteobacteria (genus Sphingopyxis) were the dominant MTBE degraders. Previous studies have suggested a role for Firmicutes in anaerobic MTBE degradation; however, the putative MTBE-degrading microorganism in the current study is a novel MTBE-degrading phylotype within this phylum. Two archaeal phylotypes (genera Methanosarcina and Methanocorpusculum) were also enriched in the heavy fractions, and these organisms may be responsible for minor amounts of MTBE degradation or for the uptake of metabolites released from the primary MTBE degraders. Currently, limited information exists on the microorganisms able to degrade MTBE under anaerobic conditions. This work represents the first application of DNA-based SIP to identify anaerobic MTBE-degrading microorganisms in laboratory microcosms and therefore provides a valuable set of data to definitively link identity with anaerobic MTBE degradation. PMID:22327600

  15. Treatment of Methyl tert-Butyl Ether Vapors in Biotrickling Filters. 1.

    E-print Network

    . Introduction Methyltert-butyl ether (MTBE) was first introduced in United States in the late 1970s as an octane among all chemicals in 1993. At the same time, an increasing number of groundwater contaminations

  16. Evaluating UV/H2O2 processes for methyl tert-butyl ether and tertiary butyl alcohol removal: effect of pretreatment options and light sources.

    PubMed

    Li, Ke; Hokanson, David R; Crittenden, John C; Trussell, Rhodes R; Minakata, Daisuke

    2008-12-01

    In this paper, we evaluate the efficiency of UV/H2O2 process to remove methyl tert-butyl ether (MtBE) and tertiary butyl alcohol (tBA) from a drinking water source. Kinetic models were used to evaluate the removal efficiency of the UV/H2O2 technologies with different pretreatment options and light sources. Two commercial UV light sources, i.e. low pressure, high intensity lamps and medium pressure, high intensity lamps, were evaluated. The following pretreatment alternatives were evaluated: (1) ion exchange softening with seawater regeneration (NaIX); (2) Pellet Softening; (3) weak acid ion exchange (WAIX); and (4) high pH lime softening followed by reverse osmosis (RO). The presence or absence of a dealkalization step prior to the UV/H2O2 Advanced Oxidation Process (AOP) was also evaluated for each pretreatment possibility. Pretreatment has a significant impact on the performance of UV/H2O2 process. The NaIX with dealkalization was shown to be the most cost effective. The electrical energy per order (EEO) values for MtBE and tBA using low pressure high output UV lamps (LPUV) and 10mg/LH2O2 are 0.77 and 3.0 kWh/kgal-order, or 0.20 and 0.79 kWh/m3-order, respectively. For medium pressure UV high output lamps (MPUV), EEO values for MtBE and tBA are 4.6 and 15 kWh/kgal-order, or 1.2 and 4.0 kWh/m3-order, for the same H2O2 dosage. PMID:18951605

  17. Exposure to methyl tert-butyl ether, benzene, and total hydrocarbons at the Singapore-Malaysia causeway immigration checkpoint

    SciTech Connect

    Tan, C.; Ong, H.Y.; Kok, P.W.

    1996-12-31

    The primary aim of this study was to determine the extent and levels of exposure to volatile organic compounds (VOCs) from automobile emissions in a group of immigration officers at a busy cross-border checkpoint. A majority (80%) of the workers monitored were exposed to benzene at levels between 0.01 and 0.5 ppm, with only 1.2% exceeding the current Occupational Safety and Health Administration occupational exposure limit of 1 ppm. The geometric mean (GM) concentrations of 8-hr time-weighted average exposure were 0.03 ppm, 0.9 ppm, and 2.46 ppm for methyl-tert-butyl ether (MTBE), benzene, and total hydrocarbons (THC), respectively. The highest time-weighted average concentrations measured were 1.05 ppm for MTBE, 2.01 ppm for benzene, and 34 ppm for THC. It was found that motorbikes emitted a more significant amount of pollutants compared with motor cars. On average, officers at the motorcycle booths were exposed to four to five times higher levels of VOCs (GMs of 0.07 ppm, 0.23 ppm, and 4.7 ppm for MTBE, benzene, and THC) than their counterparts at the motor car booths (GMs of 0.01 ppm, 0.05 ppm, and 1.5 ppm). The airborne concentrations of all three pollutants correlated with the flow of vehicle traffic. Close correlations were also noted for the concentrations in ambient air for the three pollutants measured. Benzene and MTBE had a correlation coefficient of 0.97. The overall findings showed that the concentrations of various VOCs were closely related to the traffic density, suggesting that they were from a common source, such as exhaust emissions from the vehicles. The results also indicated that although benzene, MTBE, and THC are known to be volatile, a significant amount could still be detected in the ambient environment, thus contributing to our exposure to these compounds. 4 refs., 6 figs.

  18. Whole-Genome Analysis of the Methyl tert-Butyl Ether-Degrading Beta-Proteobacterium Methylibium petroleiphilum PM1? †

    PubMed Central

    Kane, Staci R.; Chakicherla, Anu Y.; Chain, Patrick S. G.; Schmidt, Radomir; Shin, Maria W.; Legler, Tina C.; Scow, Kate M.; Larimer, Frank W.; Lucas, Susan M.; Richardson, Paul M.; Hristova, Krassimira R.

    2007-01-01

    Methylibium petroleiphilum PM1 is a methylotroph distinguished by its ability to completely metabolize the fuel oxygenate methyl tert-butyl ether (MTBE). Strain PM1 also degrades aromatic (benzene, toluene, and xylene) and straight-chain (C5 to C12) hydrocarbons present in petroleum products. Whole-genome analysis of PM1 revealed an ?4-Mb circular chromosome and an ?600-kb megaplasmid, containing 3,831 and 646 genes, respectively. Aromatic hydrocarbon and alkane degradation, metal resistance, and methylotrophy are encoded on the chromosome. The megaplasmid contains an unusual t-RNA island, numerous insertion sequences, and large repeated elements, including a 40-kb region also present on the chromosome and a 29-kb tandem repeat encoding phosphonate transport and cobalamin biosynthesis. The megaplasmid also codes for alkane degradation and was shown to play an essential role in MTBE degradation through plasmid-curing experiments. Discrepancies between the insertion sequence element distribution patterns, the distributions of best BLASTP hits among major phylogenetic groups, and the G+C contents of the chromosome (69.2%) and plasmid (66%), together with comparative genome hybridization experiments, suggest that the plasmid was recently acquired and apparently carries the genetic information responsible for PM1's ability to degrade MTBE. Comparative genomic hybridization analysis with two PM1-like MTBE-degrading environmental isolates (?99% identical 16S rRNA gene sequences) showed that the plasmid was highly conserved (ca. 99% identical), whereas the chromosomes were too diverse to conduct resequencing analysis. PM1's genome sequence provides a foundation for investigating MTBE biodegradation and exploring the genetic regulation of multiple biodegradation pathways in M. petroleiphilum and other MTBE-degrading beta-proteobacteria. PMID:17158667

  19. Enhancing Transport of Hydrogenophaga flava ENV735 for Bioaugmentation of Aquifers Contaminated with Methyl tert-Butyl Ether

    PubMed Central

    Streger, Sheryl H.; Vainberg, Simon; Dong, Hailiang; Hatzinger, Paul B.

    2002-01-01

    The gasoline oxygenate methyl tert-butyl ether (MTBE) has become a widespread contaminant in groundwater throughout the United States. Bioaugmentation of aquifers with MTBE-degrading cultures may be necessary to enhance degradation of the oxygenate in some locations. However, poor cell transport has sometimes limited bioaugmentation efforts in the past. The objective of this study was to evaluate the transport characteristics of Hydrogenophaga flava ENV735, a pure culture capable of growth on MTBE, and to improve movement of the strain through aquifer solids. The wild-type culture moved only a few centimeters in columns of aquifer sediment. An adhesion-deficient variant (H. flava ENV735:24) of the wild-type strain that moved more readily through sediments was obtained by sequential passage of cells through columns of sterile sediment. Hydrophobic and electrostatic interaction chromatography revealed that the wild-type strain is much more hydrophobic than the adhesion-deficient variant. Electrophoretic mobility assays and transmission electron microscopy showed that the wild-type bacterium contains two distinct subpopulations, whereas the adhesion-deficient strain has only a single, homogeneous population. Both the wild-type strain and adhesion-deficient variant degraded MTBE, and both were identified by 16S rRNA analysis as pure cultures of H. flava. The effectiveness of surfactants for enhancing transport of the wild-type strain was also evaluated. Many of the surfactants tested were toxic to ENV735; however, one nonionic surfactant, Tween 20, enhanced cell transport in sand columns. Improving microbial transport may lead to a more effective bioaugmentation strategy for MTBE-contaminated sites where indigenous oxygenate degraders are absent. PMID:12406751

  20. Whole-genorne analysis of the methyl tert-butyl ether-degrading beta-proteobacterium Methylibium petroleiphilum PM1

    SciTech Connect

    Kane, Staci R.; Chakicherla, Anu Y.; Chain, Patrick S. G.; Schmidt, Radomir; Shin, M; Legler, Tina C.; Scow, Kate M.; Larimer, Frank W; Lucas, Susan; Richardson, P M; Hristova, Krassimira R.

    2007-03-01

    Methylibium petroleiphilum PM1 is a methylotroph distinguished by its ability to completely metabolize the fuel oxygenate methyl tert-butyl ether (MTBE). Strain PM1 also degrades aromatic (benzene, toluene, and xylene) and straight-chain (C, to C,,) hydrocarbons present in petroleum products. Whole-genome analysis of PM1 revealed an similar to 4-Mb circular chromosome and an similar to 600-kb megaplasmid, containing 3,831 and 646 genes, respectively. Aromatic hydrocarbon and alkane degradation, metal resistance, and methylotrophy are encoded on the chromosome. The megaplasmid contains an unusual t-RNA island, numerous insertion sequences, and large repeated elements, including a 40-kb region also present on the chromosome and a 29-kb tandem repeat encoding phosphonate transport and cobalamin biosynthesis. The megaplasmid also codes for alkane degradation and was shown to play an essential role in MTBE degradation through plasmid-curing experiments. Discrepancies between the insertion sequence element distribution patterns, the distributions of best BLASTP hits among major phylogenetic groups, and the G+C contents of the chromosome (69.2%) and plasmid (66%), together with comparative genome hybridization experiments, suggest that the plasmid was recently acquired and apparently carries the genetic information responsible for PM1's ability to degrade MTBE. Comparative genomic hybridization analysis with two PM1-like MTBE-degrading environmental isolates (similar to 99% identical 16S rRNA gene sequences) showed that the plasmid was highly conserved (ca. 99% identical), whereas the chromosomes were too diverse to conduct resequencing analysis. PM1's genome sequence provides a foundation for investigating MTBE biodegradation and exploring the genetic regulation of multiple biodegradation pathways in M. petroleiphilum and other MTBE-degrading beta-proteobacteria.

  1. [Environmental and biological monitoring of exposure to monoaromatic hydrocarbons and to methyl tert-butyl ether in a group of petrol station workers].

    PubMed

    De Palma, G; Poli, D; Manini, P; Andreoli, R; Mozzoni, P; Apostoli, P; Mutti, A

    2011-01-01

    The aim of the study was to evaluate biomarkers of exposure to gasoline in petrol station workers by a combined approach of environmental and biological monitoring. The personal exposure to benzene, toluene, ethylbenzene and xylene (BTEX) and the urinary levels of BTEX, methyl tert-butyl ether (U-MTBE), trans,trans-muconic (t,t-MA) and S-phenylmercapturic acids (S-PMA) and cotinine were determined by mass spectrometry coupled chromatographic techniques. U-MTBE levels were strictly influenced by occupational exposure to gasoline, whereas both U-B and S-PMA levels depended from smoking habits and occupational exposure. PMID:23393799

  2. Manipulation of the HIF–Vegf pathway rescues methyl tert-butyl ether (MTBE)-induced vascular lesions

    SciTech Connect

    Bonventre, Josephine A.; Kung, Tiffany S.; White, Lori A.; Cooper, Keith R.

    2013-12-15

    Methyl tert-butyl ether (MTBE) has been shown to be specifically anti-angiogenic in piscine and mammalian model systems at concentrations that appear non-toxic in other organ systems. The mechanism by which MTBE targets developing vascular structures is unknown. A global transcriptome analysis of zebrafish embryos developmentally exposed to 0.00625–5 mM MTBE suggested that hypoxia inducible factor (HIF)-regulated pathways were affected. HIF-driven angiogenesis via vascular endothelial growth factor (vegf) is essential to the developing vasculature of an embryo. Three rescue studies were designed to rescue MTBE-induced vascular lesions: pooled blood in the common cardinal vein (CCV), cranial hemorrhages (CH), and abnormal intersegmental vessels (ISV), and test the hypothesis that MTBE toxicity was HIF–Vegf dependent. First, zebrafish vegf-a over-expression via plasmid injection, resulted in significantly fewer CH and ISV lesions, 46 and 35% respectively, in embryos exposed to 10 mM MTBE. Then HIF degradation was inhibited in two ways. Chemical rescue by N-oxaloylglycine significantly reduced CCV and CH lesions by 30 and 32% in 10 mM exposed embryos, and ISV lesions were reduced 24% in 5 mM exposed zebrafish. Finally, a morpholino designed to knock-down ubiquitin associated von Hippel–Lindau protein, significantly reduced CCV lesions by 35% in 10 mM exposed embryos. In addition, expression of some angiogenesis related genes altered by MTBE exposure were rescued. These studies demonstrated that MTBE vascular toxicity is mediated by a down regulation of HIF–Vegf driven angiogenesis. The selective toxicity of MTBE toward developing vasculature makes it a potentially useful chemical in the designing of new drugs or in elucidating roles for specific angiogenic proteins in future studies of vascular development. - Highlights: • Global gene expression of MTBE exposed zebrafish suggested altered HIF1 signaling. • Over expression of zebrafish vegf-a rescues MTBE-induced vascular lesions. • Inhibiting PHD or knocking down VHL rescues MTBE-induced vascular lesions. • HIF1-Vegf driven angiogenesis is a target for MTBE vascular toxicity.

  3. Determination of Methyl tert-Butyl Ether and tert-Butyl Alcohol in Water by Solid-Phase Microextraction/Head Space Analysis in Comparison to EPA Method 5030/8260B

    SciTech Connect

    Oh, Keun-Chan; Stringfellow, William T.

    2003-10-02

    Methyl tert-butyl ether (MTBE) is now one of the most common groundwater contaminants in the United States. Groundwater contaminated with MTBE is also likely to be contaminated with tert-butyl alcohol (TBA), because TBA is a component of commercial grade MTBE, TBA can also be used as a fuel oxygenate, and TBA is a biodegradation product of MTBE. In California, MTBE is subject to reporting at concentrations greater than 3 {micro}g/L. TBA is classified as a ''contaminant of current interest'' and has a drinking water action level of 12 {micro}g/L. In this paper, we describe the development and optimization of a simple, automated solid phase microextraction (SPME) method for the analysis of MTBE and TBA in water and demonstrate the applicability of this method for monitoring MTBE and TBA contamination in groundwater, drinking water, and surface water. In this method, the headspace (HS) of a water sample is extracted with a carboxen/polydimethylsiloxane SPME fiber, the MTBE and TBA are desorbed into a gas chromatograph (GC), and detected using mass spectrometry (MS). The method is optimized for the routine analysis of MTBE and TBA with a level of quantitation of 0.3 {micro}g/L and 4 {micro}g/L, respectively, in water. MTBE quantitation was linear for over two orders of concentration (0.3 {micro}g/L -80 {micro}g/L). TBA was found to be linear within the range of 4 {micro}g/L-7,900 {micro}g/L. The lower level of detection for MTBE is 0.03 {micro}g/L using this method. This SPME method using headspace extraction was found to be advantageous over SPME methods requiring immersion of the fiber into the water samples, because it prolonged the life of the fiber by up to 400 sample analyses. This is the first time headspace extraction SPME has been shown to be applicable to the measurement of both MTBE and TBA at concentrations below regulatory action levels. This method was compared with the certified EPA Method 5030/8260B (purge-and-trap/GC/MS) using split samples from laboratory bioreactors treating MTBE contaminated water and applied to environmental samples collected throughout the East Bay area of California. Results from the SPME-HS/GC/MS method were directly comparable to the EPA Method 5030/8260B. This method provides an simple, inexpensive, accurate, and sensitive alternative to EPA Method 5030/8260B for the analysis of MTBE and TBA in water samples.

  4. METHYL TERT-BUTYLETHER-WATER INTERACTION

    EPA Science Inventory

    Methyl tert-butyl ether (MTBE) is a well-known environmental contaminant owing to its high solubility in water. Since the early 1990s, MTBE has been added to gasoline to improve air quality in some metropolitan areas of the United States. Improved air quality was, however, achiev...

  5. Methyl tert-butyl ether degradation in the unsaturated zone and the relation between MTBE in the atmosphere and shallow groundwater

    USGS Publications Warehouse

    Baehr, A.L.; Charles, E.G.; Baker, R.J.

    2001-01-01

    Atmospheric methyl tert-butyl ether (MTBE) concentrations in southern New Jersey generally exceeded concentrations in samples taken from the unsaturated zone. A simple unsaturated zone transport model indicates that MTBE degradation can explain the attenuation with half-lives from a few months to a couple of years. Tert-butyl alcohol (TBA), a possible degradation product of MTBE, was detected in unsaturated-zone samples at concentrations exceeding atmospheric levels at some sites, suggesting the possible conversion of MTBE to TBA. At sites where MTBE was detected in shallow groundwater, the concentration was typically higher than the overlying unsaturated-zone concentration. This observation is consistent with outgassing from the aquifer and combined with the unsaturated-zone attenuation suggests some of the MTBE detections in shallow groundwater are nonatmospheric in origin, coming from leaking tanks, road runoff, or other sources. The identification of sources of MTBE in groundwater and attenuation mechanisms through the hydrologic cycle is critical in developing an understanding of the long-term effect of MTBE releases.

  6. Expression of an alkane monooxygenase (alkB) gene and methyl tert-butyl ether co-metabolic oxidation in Pseudomonas citronellolis.

    PubMed

    Bravo, Ana Luisa; Sigala, Juan Carlos; Le Borgne, Sylvie; Morales, Marcia

    2015-04-01

    Pseudomonas citronellolis UAM-Ps1 co-metabolically transforms methyl tert-butyl ether (MTBE) to tert-butyl alcohol with n-pentane (2.6 mM), n-octane (1.5 mM) or dicyclopropylketone (DCPK) (4.4 mM), a gratuitous inducer of alkane hydroxylase (AlkB) activity. The reverse transcription quantitative real-time PCR was used to quantify the alkane monooxygenase (alkB) gene expression. The alkB gene was expressed in the presence of n-alkanes and DCPK and MTBE oxidation occurred only in cultures when alkB was transcribed. A correlation between the number of alkB transcripts and MTBE consumption was found (???? consumption in ?mol = 1.44e(-13) x DNA copies, R(2) = 0.99) when MTBE (0.84 mM) was added. Furthermore, alkB was cloned and expressed into Escherichia coli and the recombinant AlkB had a molecular weight of 42 kDa. This is the first report where the expression of alkB is related to the co-metabolic oxidation of MTBE. PMID:25432418

  7. Occurrence of methyl tert-butyl ether (MTBE) in riverbank fiftered water and drnking water produced by riverbank filtration. 2.

    PubMed

    Achten, Christine; Kolb, Axel; Püttmann, Wilhelm

    2002-09-01

    Bank filtration of river or lake water represents an efficient and natural purification process used for the drinking water production in many countries and at an amount of about 15-16% in Germany. From experiences over decades particularly at the river Rhine and Elbe, it is known that the occurrence of persistent pollutants in river water can represent a problem for the quality of drinking water produced by bank filtration. The common detection of the gasoline additive methyl tert-butyl ether (MTBE) in drinking water and the announced phase-out of the oxygenate in the U.S. show that MTBE can contaminate large water amounts due to its physicochemical properties. The MTBE situation in the U.S differs from Europe, and significantly lower concentrations in the German environment can be expected. Average MTBE concentrations of 200-250 ng/L in the Lower Main and Lower Rhine river in 2000/2001 were reported. At two sites at the Lower Rhine and Lower Main rivers MTBE concentrations in bank filtered water (n = 22), recovering well water, raw water, and drinking water produced by the water utility at the Lower Rhine site (n = 30) and tap water at Frankfurt/M City (n = 13) were analyzed from 1999 to 2001. Sample analysis is performed by a combination of headspace-solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC/MS) with a detection limit of 10 ng/L and a relative standard deviation of 11%. At the Lower Rhine site up to 80 m from the river an average MTBE concentration of 88 ng/L in riverbank filtered water, recovering well water, and raw water (n = 7) and of 43-110 ng/L in drinking water (n = 3) result. At the Lower Main site up to 400 m from the river MTBE concentrations from 52 to 250 ng/L (n = 7) were measured. Tap water samples at Frankfurt/M (mean of 35 ng/L, maximum of 71 ng/L) were in the same range as MTBE amounts in drinking water at the Lower Rhine site. Measured MTBE amounts eliminated by bank filtration at the Lower Rhine site are comparable to other contaminants. The results of this study show that concentrations measured in river water and drinking water are approximately 2-3 orders of magnitude lower than the U.S. drinking water standard of 20-40 microg/L, represent trace-level concentrations, and are not of major concern nowadays. However, the unfavorable combination of the occurrence of nonpoint MTBE emissions and the persistent behavior of the ether in water even at low concentrations should not be neglected in future discussion. The reported MTBE concentrations are relevant for precautionary aspects. MTBE concentrations in German river water show a tendency toward increasing concentrations since 1999, and in the future possible higher concentrations could represent a risk for the quality of drinking water that is being produced by water utility using bank filtered river water. PMID:12322735

  8. Methyl tert-butyl ether (MTBE) detected in abnormally high concentrations in postmortem blood and urine from two persons found dead inside a car containing a gasoline spill.

    PubMed

    Karinen, Ritva; Vindenes, Vigdis; Morild, Inge; Johnsen, Lene; Le Nygaard, Ilah; Christophersen, Asbjørg S

    2013-09-01

    Two deep frozen persons, a female and a male, were found dead in a car. There had been an explosive fire inside the car which had extinguished itself. On the floor inside the car were large pools of liquid which smelled of gasoline. The autopsy findings and routine toxicological analyses could not explain the cause of death. Carboxyhemoglobin levels in the blood samples were <10%. Analysis with a headspace gas chromatography revealed methyl tert-butyl ether (MTBE) concentrations of 185 mg/L (female victim) and 115 mg/L (male victim) in peripheral blood. The urine MTBE concentrations were 150 mg/L and 256 mg/L, respectively. MTBE is a synthetic chemical which is added to gasoline as a fuel oxygenate. Gasoline poisoning is likely to be the cause of the death in these two cases, and MTBE can be a suitable marker of gasoline exposure, when other volatile components have vaporized. PMID:23879346

  9. Simultaneous determination of methyl tert-butyl ether, its degradation products and other gasoline additives in soil samples by closed-system purge-and-trap gas chromatography-mass spectrometry.

    PubMed

    Rosell, Mònica; Lacorte, Sílvia; Barceló, Damià

    2006-11-01

    A new protocol for the simultaneous determination of methyl tert-butyl ether (MTBE); its main degradation products: tert-butyl alcohol (TBA) and tert-butyl formate (TBF); other gasoline additives, oxygenate dialkyl ethers: ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME) and diisopropyl ether (DIPE); aromatics: benzene, toluene, ethylbenzene and xylenes (BTEX) and other compounds causing odour events such as dicyclopentadiene (DCPD) and trichloroethylene (TCE) in soils has been developed. On the basis of US Environmental Protection Agency (EPA) method 5035A, a fully automated closed-system purge-and-trap coupled to gas chromatography/mass spectrometry (P&T-GC/MS) was optimised and permitted to detect microg/kg concentrations in solid matrices avoiding losses of volatile compounds during operation processes. Parameters optimised were the sampling procedure, sample preservation and storage, purging temperature, matrix effects and quantification mode. Using 5 g of sample, detection limits were between 0.02 and 1.63 microg/kg and acceptable method precision and accuracy was obtained provided quantification was performed using adequate internal standards. Soil samples should be analysed as soon as possible after collection, stored under -15 degrees C for not longer than 7 days if degradation products have to be analysed. The non-preservative alternative (empty vial) provided good recoveries of the most analytes when freezing the samples up to 7 day holding time, however, if biologically active soil are analysed the preservation with trisodium phosphate dodecahydrate (Na(3)PO(4).12H(2)O or TSP) is strongly recommended more than sodium bisulphate (NaHSO(4)). The method was finally applied to provide threshold and background levels of several gasoline additives in a point source and in sites not influenced by gasoline spills. The proposed method provides the directions for the future application on real samples in current monitoring programs at gasoline pollution risk sites where till now little monitoring data for MTBE in soils are available. PMID:16904119

  10. Tetra­chlorido­[N 2,N 2?-(di­methyl­silanedi­yl)bis­(N-tert-butyl-3-methyl­benzimid­amid­ato)-?2 N 2,N 2?]hafnium(IV)

    PubMed Central

    Wang, Tao; Zhao, Jian-Ping; Bai, Sheng-Di

    2013-01-01

    The symmetric title mol­ecule, [Hf(C26H40N4Si)Cl4], lies about a twofold rotation axis. The HfIV and Si atoms lie on the rotation axis with all other atoms being in general positions. The HfIV atom is six-coordinated by two N atoms from the N 2,N 2?-(di­methyl­silanedi­yl)bis­(N-tert-butyl-3-methyl­benz­imid­amidate) ligand and four Cl? ions in a slightly distorted octa­hedral geometry. The two amidinate moieties are connected through the central Si atom with Si—N bond length of 1.762?(3)?Å, generating the characteristic N—C—N—Si—N—C—N skeleton of a silyl-linked ansa-bis­(amidine) species. PMID:24454166

  11. Response surface analysis of photocatalytic degradation of methyl tert-butyl ether by core/shell Fe3O4/ZnO nanoparticles

    PubMed Central

    2014-01-01

    The degradation of methyl tert-butyl ether (MTBE) was investigated in the aqueous solution of coated ZnO onto magnetite nanoparticale based on an advanced photocatalytic oxidation process. The photocatalysts were synthesized by coating of ZnO onto magnetite using precipitation method. The sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibration sample magnetometer (VSM). Besides, specific surface area was also determined by BET method. The four effective factors including pH of the reaction mixture, Fe3O4/ZnO magnetic nanoparticles concentration, initial MTBE concentration and molar ratio of [H2O2]/ [MTBE] were optimized using response surface modeling (RSM). Using the four-factor-three-level Box–Behnken design, 29 runs were designed considering the effective ranges of the influential factors. The optimized values for the operational parameters under the respective constraints were obtained at PH of 7.2, Fe3O4/ZnO concentration of 1.78 g/L, initial MTBE concentration of 89.14 mg/L and [H2O2]/ [MTBE] molar ratio of 2.33. Moreover, kinetics of MTBE degradation was determined under optimum condition. The study about core/shell magnetic nanoparticles (MNPs) recycling were also carried out and after about four times, the percentage of the photocatalytic degradation was about 70%. PMID:24393372

  12. Spectroscopic investigation, natural bond orbital analysis, HOMO-LUMO and thermodynamic functions of 2-tert-butyl-5-methyl anisole using DFT (B3LYP) calculations.

    PubMed

    Balachandran, V; Santhi, G; Karpagam, V; Revathi, B; Karabacak, M

    2015-02-01

    The optimized molecular structure and corresponding vibrational assignments of 2-tert-butyl-5-methyl anisole (TBMA) have been investigated using density functional theory (DFT)/B3LYP with 6-31G(d,p) and 6-311++G(d,p) basis sets investigation of the relative orientation of the methoxy group has shown two conformers (O-cis) and (O-trans) exist. The vibrational analysis of the stable conformer of the title compound is performed by means of infrared absorption and Raman spectroscopy in combination with theoretical simultaneously. The natural bond orbital (NBO) analysis is useful to understand the intra-molecular hyper conjugative interaction lone pair and ?(?)(C-C), ?(?)(C-H) bond orbital. HOMO and LUMO energies show that charge transfer occurs in the molecule, therefore; HOMO, LUMO and molecular electrostatic potential (MEP) were calculated and analyzed. (1)H and (13)C NMR spectra by using gauge including atomic orbital (GIAO) method of studied compound were compared with experimental data. The thermodynamic functions of TBMA were calculated by B3LYP/6-311+G(d,p) basis set. PMID:25448946

  13. Use of Methyl Tert-Butyl Ether for the Treatment of Refractory Intrahepatic Biliary Strictures and Bile Casts: A Modern Perspective.

    PubMed

    Kim, Gregory; Malayaman, Saninuj N; Green, Michael Stuart

    2015-01-01

    Cholelithiasis is a prevalent problem in the United States with 14% or more adults affected. Definitive treatment of cholelithiasis is cholecystectomy. When cholecystectomy yields minimal resolution treatment options include expectant management of asymptomatic gallstones or endoscopic retrograde cholangiopancreatogram. We present a case of intrahepatic biliary casts where surgical option was not possible, interventional radiology was unsuccessful, and methyl tert-butyl ether was used to dissolve the biliary obstruction. Dissolution therapy of gallstones was first reported in 1722 when Vollisnieri used turpentine in vitro. While diethyl ether has excellent solubilizing capacity, its low boiling point limited its use surgically as it vaporizes immediately. Diethyl ether can expand 120-fold during warming to body temperature after injection into the biliary system making it impractical for routine use. The use of dissolution is out of favor due to the success of laparoscopic cholecystectomy. Epidemiological studies have shown the general population should have minimal concerns from passive exposure. Dissolution using MTBE remains a viable option if surgical or endoscopic options are not available. However, because of risks involved to both the patient and the staff, careful multidisciplinary team approach must be undertaken to minimize the risks and provide the best possible care to the patient. PMID:26236535

  14. The study of binding of methyl tert-butyl ether to human telomeric G-quadruplex and calf thymus DNA by gas chromatography, a thermodynamic discussion.

    PubMed

    Ghasemi, Sahar; Ahmadi, Farhad

    2014-11-15

    Methyl-tert-butyl ether (MTBE) is widely used as an antiknock additive for increasing octane number of gasoline. Recently, the in vivo studies demonstrated that MTBE has genotoxic potential and able to form adducts with DNA. In the work, the interactions of MTBE with calf thymus DNA (ct-DNA) and the Na(+) form of G-quadruplex DNA (wtTel22) were studied by using of head space-solid phase microextraction technique coupled to gas chromatography. The binding equilibrium constants were measured through the equilibriums of a four phase system. In addition, the MTBE Henry's law constants for two different buffers in the temperature range of 283-303K were measured. Thermodynamic studies revealed that the complexation of MTBE to both DNAs is enthalpy favored and entropy disfavored. The thermodynamic results revealed that MTBE may have interaction with ct-DNA via the minor groove of DNA. Also, MTBE may be complexed into the basket of G-quadruplex structure. In addition, the low difference in the binding constants of MTBE for both different DNA targets may confirm that MTBE is poorly selective for different conformations of DNA. PMID:25280162

  15. Use of Methyl Tert-Butyl Ether for the Treatment of Refractory Intrahepatic Biliary Strictures and Bile Casts: A Modern Perspective

    PubMed Central

    Kim, Gregory; Malayaman, Saninuj N.; Green, Michael Stuart

    2015-01-01

    Cholelithiasis is a prevalent problem in the United States with 14% or more adults affected. Definitive treatment of cholelithiasis is cholecystectomy. When cholecystectomy yields minimal resolution treatment options include expectant management of asymptomatic gallstones or endoscopic retrograde cholangiopancreatogram. We present a case of intrahepatic biliary casts where surgical option was not possible, interventional radiology was unsuccessful, and methyl tert-butyl ether was used to dissolve the biliary obstruction. Dissolution therapy of gallstones was first reported in 1722 when Vollisnieri used turpentine in vitro. While diethyl ether has excellent solubilizing capacity, its low boiling point limited its use surgically as it vaporizes immediately. Diethyl ether can expand 120-fold during warming to body temperature after injection into the biliary system making it impractical for routine use. The use of dissolution is out of favor due to the success of laparoscopic cholecystectomy. Epidemiological studies have shown the general population should have minimal concerns from passive exposure. Dissolution using MTBE remains a viable option if surgical or endoscopic options are not available. However, because of risks involved to both the patient and the staff, careful multidisciplinary team approach must be undertaken to minimize the risks and provide the best possible care to the patient. PMID:26236535

  16. Interaction of insulin with methyl tert-butyl ether promotes molten globule-like state and production of reactive oxygen species.

    PubMed

    Valipour, Masoumeh; Maghami, Parvaneh; Habibi-Rezaei, Mehran; Sadeghpour, Mostafa; Khademian, Mohamad Ali; Mosavi, Khadijeh; Sheibani, Nader; Moosavi-Movahedi, Ali Akbar

    2015-09-01

    Interaction of methyl tert-butyl ether (MTBE) with proteins is a new look at its potential adverse biological effects. When MTBE is released to the environment it enters the blood stream through inhalation, and could affect the properties of various proteins. Here we investigated the interaction of MTBE with insulin and its effect on insulin structural changes. Our results showed that insulin formed a molten globule (MG)-like structure in the presence of 8 ?M MTBE under physiological pH. The insulin structural changes were studied using spectroscopy methods, viscosity calculation, dynamic light scattering and differential scanning calorimetry. To delineate the mechanisms involved in MTBE-protein interactions, the formation of reactive oxygen specious (ROS) and formation of protein aggregates were measured. The chemiluminscence experiments revealed an increase in ROS production in the presence of MTBE especially in the MG-like state. These results were further confirmed by the aggregation tests, which indicated more aggregation of insulin at 40 ?M MTBE compared with 8 ?M. Thus, the formation of initial aggregates and exposure of the hydrophobic patches upon formation of the MG-like state in the presence of MTBE drives protein oxidation and ROS generation. PMID:26193678

  17. Occurrence and temporal variability of methyl tert-butyl ether (MTBE) and other volatile organic compounds in select sources of drinking water : results of the focused survey

    USGS Publications Warehouse

    Delzer, Gregory C.; Ivahnenko, Tamara

    2003-01-01

    The large-scale use of the gasoline oxygenate methyl tert-butyl ether (MTBE), and its high solubility, low soil adsorption, and low biodegradability, has resulted in its detection in ground water and surface water in many places throughout the United States. Studies by numerous researchers, as well as many State and local environmental agencies, have discovered high levels of MTBE in soils and ground water at leaking underground gasoline-storage-tank sites and frequent occurrence of low to intermediate levels of MTBE in reservoirs used for both public water supply and recreational boating.In response to these findings, the American Water Works Association Research Foundation sponsored an investigation of MTBE and other volatile organic compounds (VOCs) in the Nation?s sources of drinking water. The goal of the investigation was to provide additional information on the frequency of occurrence, concentration, and temporal variability of MTBE and other VOCs in source water used by community water systems (CWSs). The investigation was completed in two stages: (1) reviews of available literature and (2) the collection of new data. Two surveys were associated with the collection of new data. The first, termed the Random Survey, employed a statistically stratified design for sampling source water from 954 randomly selected CWSs. The second, which is the focus of this report, is termed the Focused Survey, which included samples collected from 134 CWS source waters, including ground water, reservoirs, lakes, rivers, and streams, that were suspected or known to contain MTBE. The general intent of the Focused Survey was to compare results with the Random Survey and provide an improved understanding of the occurrence, concentration, temporal variability, and anthropogenic factors associated with frequently detected VOCs. Each sample collected was analyzed for 66 VOCs, including MTBE and three other ether gasoline oxygenates (hereafter termed gasoline oxygenates). As part of the Focused Survey, 451 source-water samples and 744 field quality-control (QC) samples were collected from 78 ground-water, 39 reservoir and (or) lake, and 17 river and (or) stream source waters at fixed intervals for a period of 1 year.Using a common assessment level of 0.2 ?g/L (micrograms per liter) (2.0 ?g/L for methyl ethyl ketone), 37 of the 66 VOCs analyzed were detected in both surveys. However, VOCs, especially MTBE and other gasoline oxygenates, were detected more frequently in the Focused Survey than in the Random Survey. MTBE was detected in 55.5 percent of the CWSs sampled in the Focused Survey and in 8.7 percent of those sampled in the Random Survey. Little difference in occurrence, however, was observed for trihalomethanes (THMs), which were detected in 16.4 and 14.8 percent of Focused Survey and The large-scale use of the gasoline oxygenate methyl tert-butyl ether (MTBE), and its high solubility, low soil adsorption, and low biodegradability, has resulted in its detection in ground water and surface water in many places throughout the United States. Studies by numerous researchers, as well as many State and local environmental agencies, have discovered high levels of MTBE in soils and ground water at leaking underground gasoline-storage-tank sites and frequent occurrence of low to intermediate levels of MTBE in reservoirs used for both public water supply and recreational boating.In response to these findings, the American Water Works Association Research Foundation sponsored an investigation of MTBE and other volatile organic compounds (VOCs) in the Nation?s sources of drinking water. The goal of the investigation was to provide additional information on the frequency of occurrence, concentration, and temporal variability of MTBE and other VOCs in source water used by community water systems (CWSs). The investigation was completed in two stages: (1) reviews of available literature and (2) the collection of new data. Two surveys wer

  18. Structural and spectral studies of some coordination complexes of a phenol-functionalized diazamesocyclic ligand 1,4-bis-(3- tert-butyl-5-methyl-2-hydroxybenzyl)-1,4-diazacycloheptane ( H2L)

    NASA Astrophysics Data System (ADS)

    Guo, Ya-Mei; Du, Miao; Wang, Gui-Chang; Bu, Xian-He

    2002-12-01

    A series of four-coordinated monomeric Cu II, Co II, and Ni II complexes of a tetradentate diazamesocyclic ligand containing bulky phenolate donor pendants, [Cu L] ( 1), [Cu( HL)]ClO 4 ( 2), [Co L] ( 3), and [Ni L] ( 4), where H2L=1,4-bis-(3- tert-butyl-5-methyl-2-hydroxybenzyl)-1,4-diazacycloheptane, have been synthesized and characterized by elemental analyses, IR, UV-vis and ESR spectra. The crystal structure of complex 1 has been determined by X-ray diffraction analysis.

  19. Methyl tert-butyl ether (MTBE) and other volatile organic compounds in lakes in Byram Township, Sussex County, New Jersey, summer 1998

    USGS Publications Warehouse

    Baehr, Arthur L.; Zapecza, Otto S.

    1998-01-01

    Water samples were collected from four lakes in Byram Township, Sussex County, N.J., in the summer of 1998 as part of an investigation of the occurrence of volatile organic compounds (VOCs) in domestic wells of lakeside communities. Cranberry Lake and Lake Lackawanna are surrounded by densely populated communities where the use of gasoline-powered watercraft is prevalent, and water is supplied by lakeside wells. Forest Lake is surrounded by a densely populated community where the use of gasoline-powered watercraft is prohibited. Stag Pond is privately owned, is situated in a sparsely populated area, and is not navigated by gasoline-powered watercraft. Samples were collected from Cranberry Lake in early summer and again in late summer 1998. Concentrations of the gasoline oxygenate methyl tert-butyl ether (MTBE) ranged from 1.6 to 15.0 mg/L (micrograms per liter) on June 24 and decreased with depth. The depth-related concentration gradient is attributed to density stratification caused by the temperature gradient that is present in the lake during the early summer. MTBE concentrations ranged from 7.4 to 29.0 mg/L on September 8 and were uniform with depth, as was water temperature, indicating that the lake was vertically mixed. On the basis of these concentration profiles, the mass of MTBE in Cranberry Lake was estimated to be 15 kilograms on June 24 and 27 kilograms on September 8. These mass estimates are equal to the amount of MTBE in 52 and 95 gallons, respectively, of gasoline that contains 10 percent MTBE by volume. Concentrations of another gasoline oxygenate, tert-amyl-methyl ether (TAME), ranged from 0.07 to 0.43 mg/L on June 24 and from 0.2 to 0.69 mg/L on September 8. The highest concentrations of benzene, toluene, ethylbenzene, and xylenes (BTEX) were 0.18, 1.2, 0.18, and 0.97 mg/L, respectively, on June 24. All BTEX concentrations in Cranberry Lake on September 8 were less than 0.2 mg/L. Samples were collected from Lake Lackawanna on September 9. Concentrations of MTBE and TAME ranged from 3.7 to 14.0 mg/L and from 0.17 to 0.38 mg/L, respectively. Like those in Cranberry Lake the previous day, BTEX concentrations were less than 0.2 mg/L, and VOC concentrations and water temperatures were nearly uniform with depth. The mass of MTBE in Lake Lackawanna on September 9 was estimated to be 6 kilograms, which is equal to the amount of MTBE in 21 gallons of gasoline that contains10 percent MTBE by volume. All VOC concentrations were less than 0.2 mg/L in samples collected from Forest Lake on September 8, 1998, and from Stag Pond on the following day. Oxygenated gasoline is used in watercraft on lakes across northern New Jersey. Many of these lakes are surrounded by communities similar to those at Cranberry Lake and at Lake Lackawanna, which depend largely on wells for water supply. Therefore, a regional assessment of the occurrence of these compounds in lakes and ground water is needed to determine the effect of the use of oxygenated gasoline on water quality in lakeside environments throughout northern New Jersey.

  20. OCCURRENCE OF METYL TERT-BUTYL ETHER (MTBE) AT FIVE MARINAS IN LAKE TEXOMA

    EPA Science Inventory



    Occurrence of methyl tert-butyl ether (MTBE) in five marinas was monitored between June 1999 and November 2000 in Lake Texoma located on the border of Oklahoma and Texas. MTBE is a commonly used gasoline additive and a suspected carcinogen. Lake water was collected at loc...

  1. 4-tert-Butyl­pyridinium chloride–4,4?-(propane-2,2-di­yl)bis­(2,6-di­methyl­phenol)–toluene (2/2/1)

    PubMed Central

    Nielson, Alastair J.; Waters, Joyce M.

    2014-01-01

    In the title solvated salt, C9H14N+·Cl?·C19H24O2·0.5C7H7, two mol­ecules of 4,4?-(propane-2,2-di­yl)bis­(2,6-di­methyl­phenol) are linked via O—H?Cl hydrogen bonds to two chloride ions, each of which is also engaged in N—H?Cl hydrogen bonding to a 4-tert-butyl­pyridinium cation, giving a cyclic hydrogen-bonded entity centred at 1/2, 1/2, 1/2. The toluene solvent mol­ecule resides in the lattice and resides on an inversion centre; the disorder of the methyl group requires it to have a site-occupancy factor of 0.5. No crystal packing channels are observed. PMID:24826127

  2. 4-tert-Butyl-pyridinium chloride-4,4'-(propane-2,2-di-yl)bis-(2,6-di-methyl-phenol)-toluene (2/2/1).

    PubMed

    Nielson, Alastair J; Waters, Joyce M

    2014-04-01

    In the title solvated salt, C9H14N(+)·Cl(-)·C19H24O2·0.5C7H7, two mol-ecules of 4,4'-(propane-2,2-di-yl)bis-(2,6-di-methyl-phenol) are linked via O-H?Cl hydrogen bonds to two chloride ions, each of which is also engaged in N-H?Cl hydrogen bonding to a 4-tert-butyl-pyridinium cation, giving a cyclic hydrogen-bonded entity centred at 1/2, 1/2, 1/2. The toluene solvent mol-ecule resides in the lattice and resides on an inversion centre; the disorder of the methyl group requires it to have a site-occupancy factor of 0.5. No crystal packing channels are observed. PMID:24826127

  3. National survey of Methyl tert-Butyl Ether and other Volatile Organic Compounds in drinking-water sources: Results of the random source-water survey

    USGS Publications Warehouse

    Grady, Stephen J.

    2002-01-01

    Methyl tert-butyl ether (MTBE) was detected in source water used by 8.7 percent of randomly selected community water systems (CWSs) in the United States at concentrations that ranged from 0.2 to 20 micrograms per liter (?g/L). The Random Survey conducted by the U.S. Geological Survey, in cooperation with the Metropolitan Water District of Southern California and the Oregon Health & Science University, was designed to provide an assessment of the frequency of detection, concentration, and distribution of MTBE, three other ether gasoline oxygenates, and 62 other volatile organic compounds (VOCs) in ground- and surface-water sources used for drinking-water supplies. The Random Survey was the first of two components of a national assessment of the quality of source water supplying CWSs sponsored by the American Water Works Association Research Foundation. A total of 954 CWSs were selected for VOC sampling from the population of nearly 47,000 active, self-supplied CWSs in all 50 States, Native American Lands, and Puerto Rico based on a statistical design that stratified on CWS size (population served), type of source water (ground and surface water), and geographic distribution (State).At a reporting level of 0.2 ?g/L, VOCs were detected in 27 percent of source-water samples collected from May 3, 1999 through October 23, 2000. Chloroform (in 13 percent of samples) was the most frequently detected of 42 VOCs present in the source-water samples, followed by MTBE. VOC concentrations were generally less than 10 ?g/L?95 percent of the 530 detections?and 63 percent were less than 1.0 ?g/L. Concentrations of 1,1-dichloroethene, tetrachloroethene, trichloroethene, vinyl chloride, and total trihalomethanes (TTHMs), however, exceeded drinking-water regulations in eight samples.Detections of most VOCs were more frequent in surface-water sources than in ground-water sources, with gasoline compounds collectively and MTBE individually detected significantly more often in surface water. Use of personal and commercial motorized watercraft on surface-water bodies that are drinking-water sources is probably the reason for the elevated detections of gasoline contaminants relative to ground water. MTBE detections demonstrated a seasonal pattern with more frequent detections in surface water in summer months, which is consistent with seasonal watercraft use.The detection frequency of most VOCs was significantly related to urban land use and population density. Detections of any VOC, non-trihalo-methane compounds, gasoline compounds collectively, the specific gasoline compounds benzene, toluene, ethylbenzene, and xylenes (BTEX), MTBE, solvents, and refrigerants were significantly greater in areas with more than 60 percent urban land use and (or) population density greater than 1,000 people per square mile than in source waters from less urbanized or lower population-density areas. MTBE detections were five times more frequent in source waters from areas with high MTBE use than in source waters from low or no MTBE use, but, unlike other gasoline compounds, MTBE detections were not significantly related to the density of gasoline storage tanks near drinking-water sources.

  4. Methyl tert-butyl ether in ground and surface water of the United States: National-scale relations between MTBE occurrence in surface and ground water and MTBE use in gasoline

    USGS Publications Warehouse

    Moran, M.J.; Clawges, R.M.; Zogorski, J.S.

    2002-01-01

    The detection frequency of methyl tert-butyl ether (MTBE) in ground and surface water of the United States is positively related to the content of MTBE in gasoline in various metropolitan areas of the U.S. The frequency of detection of MTBE is generally higher in areas that use larger amounts of MTBE in gasoline. Sampling of surface and ground water by the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program between 1993 and 1998 revealed a frequent detection of low concentrations of MTBE. In this analysis, data from several national-scale gasoline surveys are examined and data from one survey that is most extensive in geographic and temporal coverage is used to relate the detection of MTBE in ground and surface water to the volumetric content of MTBE in gasoline.

  5. Aerobic mineralization of MTBE and tert-butyl alcohol by stream-bed sediment microorganisms

    USGS Publications Warehouse

    Bradley, P.M.; Landmeyer, J.E.; Chapelle, F.H.

    1999-01-01

    Microorganisms indigenous to the stream-bed sediments at two gasoline- contaminated groundwater sites demonstrated significant mineralization of the fuel oxygenates, methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Up to 73% of [U-14C]-MTBE and 84% of [U-14C]-TBA were degraded to 14CO2 under mixed aerobic/anaerobic conditions. No significant mineralization was observed under strictly anaerobic conditions. The results indicate that, under the mixed aerobic/anaerobic conditions characteristic of stream-bed sediments, microbial processes may provide a significant environmental sink for MTBE and TBA delivered to surface water bodies by contaminated groundwater or by other sources.Microorganisms indigenous to the stream-bed sediments at two gasoline-contaminated groundwater sites demonstrated significant mineralization of the fuel oxygenates, methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Up to 73% of [U-14C]-MTBE and 84% of [U-14C]-TBA were degraded to 14CO2 under mixed aerobic/anaerobic conditions. No significant mineralization was observed under strictly anaerobic conditions. The results indicate that, under the mixed aerobic/anaerobic conditions characteristic of stream-bed sediments, microbial processes may provide a significant environmental sink for MTBE and TBA delivered to surface water bodies by contaminated groundwater or by other sources.

  6. 27 CFR 21.101 - tert-Butyl alcohol.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false tert-Butyl alcohol. 21.101 Section 21.101 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants §...

  7. 27 CFR 21.101 - tert-Butyl alcohol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false tert-Butyl alcohol. 21.101 Section 21.101 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants §...

  8. 27 CFR 21.101 - tert-Butyl alcohol.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false tert-Butyl alcohol. 21.101 Section 21.101 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants §...

  9. 27 CFR 21.101 - tert-Butyl alcohol.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false tert-Butyl alcohol. 21.101 Section 21.101 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants §...

  10. 4-tert-butyl-2,6-diisopropylphenol: Another phenol inducing hemorrhage in rats.

    PubMed

    Takahashi, O; Hiraga, K

    1980-02-01

    Male Sprague-Dawley rats were fed with 3,5-di-tert-butylphenol, 2,4-di-tert-butylphenol, 4-tert-butyl-2,6-diisopropylphenol, 2-tert-butyl-4-sec-butylphenol or 2-,6-di-tert-butyl-4-methylphenol (BHT) at a level of 2.27 mmol% in the diet for 1 week. One rat given 4-tert-butyl-2,6diisopropylphenol died: post mortem examination revealed hematocoelia, intratesticular, intraepididymal and intramuscular hematoma. The other rats in this group suffered from severe hemorrhagic anemia; and the prothombin index was significantly decreased. PMID:7466839

  11. Effect of Parameters on Oxychlorination of Tert-Butyl Ethers

    PubMed Central

    Gaca, Jerzy; Gackowska, Alicja; Belt, Natalia

    2008-01-01

    The effect of concentration, molar ratios of reagents, pH, and temperature on formation of chloro-organic products in reaction of tert-butyl ethers with chloride ions and hydrogen peroxide has been determined. A significant effect of Cl? ions and H2O2 molar ratios on the rate of chloro-organic product formation has been observed. Studies on oxychlorination of tert-butylethyl ether (ETBE) at pH 7, 3.5, and 2.5 have been carried out. It was found that introduction of hydronium ions into the reaction system considerably hastened the process of chloro-organic product formation. Hydronium ions contribute to the formation of the reactive tert-butyl carbocation, which undergoes secondary reactions in the presence of reactive forms of chlorine and oxygen. Moreover, the effect of temperature on ETBE (tert-butylethyl ether) and MTBE (tert-butylmethyl ether) conversions was verified. The reactions of MTBE and ETBE oxychlorination were carried out at temperatures of 5°C, 20°C, and 35°C. PMID:19696944

  12. Dimeric water embedded within a hydrophobic cavity of tetra-( p- tert-butyl)thiacalix[4]arene

    NASA Astrophysics Data System (ADS)

    Hong, Jin; Yang, Chen; Li, Yizhi; Yang, Gaosheng; Jin, Chen; Guo, Zijian; Zhu, Longgen

    2003-08-01

    X-ray crystallographic analysis and density functional B3LYP/6-31G(d) calculation confirm that dimeric water is embedded within a hydrophobic cavity of tetra-( p- tert-butyl)thiacalix[4]arene and stabilized by hydrogen bondings of aromatic ?⋯H 2O(1) and methyl⋯H 2O(2) in the dimeric water inclusion complex with binding energies of 1.4 and 0.9 kcal mol -1 respectively, and by hydrogen bonding formed between H 2O(2) and four phenolic OH groups from an adjacent tetra-( p- tert-butyl)thiacalix[4]arene, with binding energy of 3.8-4.2 kcal mol -1.

  13. {gamma}-aminobutyric acid{sub A} (GABA{sub A}) receptor regulates ERK1/2 phosphorylation in rat hippocampus in high doses of Methyl Tert-Butyl Ether (MTBE)-induced impairment of spatial memory

    SciTech Connect

    Zheng Gang; Zhang Wenbin; Zhang Yun; Chen Yaoming; Liu Mingchao; Yao Ting; Yang Yanxia; Zhao Fang; Li Jingxia; Huang Chuanshu; Luo Wenjing Chen Jingyuan

    2009-04-15

    Experimental and occupational exposure to Methyl Tert-Butyl Ether (MTBE) has been reported to induce neurotoxicological and neurobehavioral effects, such as headache, nausea, dizziness, and disorientation, etc. However, the molecular mechanisms involved in MTBE-induced neurotoxicity are still not well understood. In the present study, we investigated the effects of MTBE on spatial memory and the expression and function of GABA{sub A} receptor in the hippocampus. Our results demonstrated that intraventricular injection of MTBE impaired the performance of the rats in a Morris water maze task, and significantly increased the expression of GABA{sub A} receptor {alpha}1 subunit in the hippocampus. The phosphorylation of ERK1/2 decreased after the MTBE injection. Furthermore, the decreased ability of learning and the reduction of phosphorylated ERK1/2 level of the MTBE-treated rats was partly reversed by bicuculline injected 30 min before the training. These results suggested that MTBE exposure could result in impaired spatial memory. GABA{sub A} receptor may play an important role in the MTBE-induced impairment of learning and memory by regulating the phosphorylation of ERK in the hippocampus.

  14. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Butyl acrylate, polymer with substituted methyl styrene, methyl...Substances § 721.6920 Butyl acrylate, polymer with substituted methyl styrene, methyl...substance identified as butyl acrylate, polymer with substituted methyl styrene,...

  15. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Butyl acrylate, polymer with substituted methyl styrene, methyl...Substances § 721.6920 Butyl acrylate, polymer with substituted methyl styrene, methyl...substance identified as butyl acrylate, polymer with substituted methyl styrene,...

  16. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Butyl acrylate, polymer with substituted methyl styrene, methyl...Substances § 721.6920 Butyl acrylate, polymer with substituted methyl styrene, methyl...substance identified as butyl acrylate, polymer with substituted methyl styrene,...

  17. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Butyl acrylate, polymer with substituted methyl styrene, methyl...Substances § 721.6920 Butyl acrylate, polymer with substituted methyl styrene, methyl...substance identified as butyl acrylate, polymer with substituted methyl styrene,...

  18. Reactivities of Substituted ?-Phenyl-N-tert-butyl Nitrones

    PubMed Central

    2015-01-01

    In this work, a series of ?-phenyl-N-tert-butyl nitrones bearing one, two, or three substituents on the tert-butyl group was synthesized. Cyclic voltammetry (CV) was used to investigate their electrochemical properties and showed a more pronounced substituent effect for oxidation than for reduction. Rate constants of superoxide radical (O2•–) reactions with nitrones were determined using a UV–vis stopped-flow method, and phenyl radical (Ph•) trapping rate constants were measured by EPR spectroscopy. The effect of N-tert-butyl substitution on the charge density and electron density localization of the nitronyl carbon as well as on the free energies of nitrone reactivity with O2•– and HO2• were computationally rationalized at the PCM/B3LYP/6-31+G**//B3LYP/6-31G* level of theory. Theoretical and experimental data showed that the rates of the reaction correlate with the nitronyl carbon charge density, suggesting a nucleophilic nature of O2•– and Ph• addition to the nitronyl carbon atom. Finally, the substituent effect was investigated in cell cultures exposed to hydrogen peroxide and a correlation between the cell viability and the oxidation potential of the nitrones was observed. Through a combination of computational methodologies and experimental methods, new insights into the reactivity of free radicals with nitrone derivatives have been proposed. PMID:24968285

  19. Bis(2-hydroxy-3-tert-butyl-5-methyl-phenyl)-methane (bis-phenol) is a potent and selective inhibitor of the secretory pathway Ca²? ATPase (SPCA1).

    PubMed

    Lai, Pei; Michelangeli, Francesco

    2012-08-01

    The secretory pathway Ca(2+) ATPase (SPCA) provides the Golgi apparatus with a Ca(2+) supply essential for Ca(2+)-dependent enzymes involved in the post-translational modification of proteins in transit through the secretory pathway. Ca(2+) in the Golgi apparatus is also agonist-releasable and plays a role in hormone-induced Ca(2+) transients. Although the Ca(2+) ATPase inhibitors thapsigargin is more selective for the sarcoplasmic-endoplasmic reticulum Ca(2+) ATPase (SERCA) than for SPCA, no inhibitor has been characterised that selectively inhibits SPCA. A number of inhibitors were assessed for their selectivity to the human SPCA1d compared to the more ubiquitous human SERCA2b. Each isoform was over-expressed in COS-7 cells and the Ca(2+)-dependent ATPase activity measured in their microsomal membranes. Both bis(2-hydroxy-3-tert-butyl-5-methyl-phenyl)methane(bis-phenol) and 2-aminoethoxydiphenylborate (2-APB) selectively inhibited SPCA1d (with IC(50) values of 0.13 ?M and 0.18 mM, respectively), which were of 62- and 8.3-fold greater potency than the values for hSERCA2b (IC(50) values; 8.1 ?M and 1.5mM, respectively). Other inhibitors tested such as bis-phenol-A, tetrabromobisphenol-A and trifluoperazine inhibited both Ca(2+) ATPases similarly. Furthermore, bis-phenol was able to mobilize Ca(2+) in cells that had been pre-treated with thapsigargin. Therefore we conclude that given the potency and selectivity of bis-phenol it may prove a valuable tool in further understanding the role of SPCA in cellular processes. PMID:22796571

  20. A plan for assessing the occurrence and distribution of methyl tert-butyl ether and other volatile organic compounds in drinking water and ambient ground water in the Northeast and Mid-Atlantic regions of the United States

    USGS Publications Warehouse

    Grady, Stephen J.; Casey, George D.

    1999-01-01

    A plan to assess the occurrence and distribution of methyl tert-butyl ether (MTBE) and other volatile organic compounds (VOCs) in drinking water and ambient ground water in the Northeast and Mid-Atlantic regions of the United States was designed to meet two primary objectives. This study will provide the U.S. Environmental Protection Agency with information on potential human exposure to MTBE and other VOCs from drinking water. In addition, the study will further the goals of the U.S. Geological Survey's (USGS) National Water Quality Assessment Program (NAWQA) by providing additional information on the occurrence and distribution of VOCs in ambient ground water beneath a large, highly urbanized part of the Nation. The study will proceed in two phases-a drinking-water assessment (phase 1) and an ambient ground-water assessment (phase 2). The drinking-water assessment will involve compilation, review, and analysis of available water- quality and ancillary data for approximately 20 percent of the community water systems in 12 States in the Northeast and Mid-Atlantic regions. This effort will summarize the occurrence and distribution of MTBE and other VOCs in drinking water supplied by 2,110 community water systems. The ambient ground-water assessment will involve compilation, review, and analysis of data on MTBE and other VOCs from previous USGS studies in the 12-State area, including regional water-quality assessments conducted for the USGS's NAWQA, plus other available State or local datasets. These data will be related, to the extent allowed by the completeness and quality of the data, to land-use patterns, population density, and other anthropogenic and natural factors using statistical tests. The occurrence and distribution of MTBE and other VOCs in ambient ground water and, to the extent possible, drinking water in relation to such factors, will be evaluated.

  1. 2,6-Di-tert-butyl-4-(methoxy­meth­yl)phenol

    PubMed Central

    Zeng, Tao; Sun, Ju-Feng

    2008-01-01

    The title compound, C16H26O2, was easily obtained in high yield when 4-bromo­methyl-2,6-di-tert-butyl­phenol was reacted with methanol. There are two independent mol­ecules in the asymmetric unit. The meth­oxy group in each of the independent mol­ecules was found to be disordered, with site-occupation factors of 0.8728?(18)/0.1272?(18) and 0.8781?(17)/0.1219?(17). PMID:21201926

  2. 2,6-Di-tert-butyl-4-(methoxy-meth-yl)phenol.

    PubMed

    Zeng, Tao; Sun, Ju-Feng

    2008-01-01

    The title compound, C(16)H(26)O(2), was easily obtained in high yield when 4-bromo-methyl-2,6-di-tert-butyl-phenol was reacted with methanol. There are two independent mol-ecules in the asymmetric unit. The meth-oxy group in each of the independent mol-ecules was found to be disordered, with site-occupation factors of 0.8728?(18)/0.1272?(18) and 0.8781?(17)/0.1219?(17). PMID:21201926

  3. he increasing frequency of detection of the widely used gasoline additive methyl tert-

    E-print Network

    T he increasing frequency of detection of the widely used gasoline additive methyl tert- butyl, the September 15, 1999, Report of the Blue Ribbon Panel on Oxygenates in Gasoline (1) states that between 5 with large releases (e.g., LUFTs). Unprecedented growth in use Use of MTBE as a gasoline additive began

  4. Control Study of Ethyl tert-Butyl Ether Reactive Distillation Muhammad A. Al-Arfaj

    E-print Network

    Al-Arfaj, Muhammad A.

    Control Study of Ethyl tert-Butyl Ether Reactive Distillation Muhammad A. Al-Arfaj Department structures for ethyl tert-butyl ether (ETBE) reactive distillation columns are studied. Two process The use of reactive distillation has grown in recent years because it results in less expensive and more

  5. Reaction of phenanthrene with tert-butylating agents under Friedel-Craft conditions

    SciTech Connect

    Pozdnyakovich, Yu.V.

    1988-10-20

    The alkylation of phenanthrene with tert-butyl alcohol in the presence of trifluoroacetic acid or with tert-butyl chloride, catalyzed by the TiCl/sub 4/, FeCl/sub 3/-CH/sub 3/NO/sub 2/, and AlCl/sub 3/-CH/sub 3/NO/sub 2/, leads to formation of 2- and 3-tert-butylphenanthrene and also 2,6-, 2,7-, and 3,6-di-tert-butylphenanthrene. The exhaustive alkylation of phenanthrene leads to the formation of the above-mentioned isomeric di-tert-butylphenanthrenes, the ratios of which depend on the nature of the catalyst.

  6. Occurrence and implications of methyl tert-butyl ether and gasoline hydrocarbons in ground water and source water in the United States and in drinking water in 12 Northeast and Mid-Atlantic States, 1993-2002

    USGS Publications Warehouse

    Moran, Michael J.; Zogorski, John S.; Squillace, Paul J.

    2004-01-01

    The occurrence and implications of methyl tert-butyl ether (MTBE) and gasoline hydrocarbons were examined in three surveys of water quality conducted by the U.S. Geological Survey?one national-scale survey of ground water, one national-scale survey of source water from ground water, and one regional-scale survey of drinking water from ground water. The overall detection frequency of MTBE in all three surveys was similar to the detection frequencies of some other volatile organic compounds (VOCs) that have much longer production and use histories in the United States. The detection frequency of MTBE was higher in drinking water and lower in source water and ground water. However, when the data for ground water and source water were limited to the same geographic extent as drinking-water data, the detection frequencies of MTBE were comparable to the detection frequency of MTBE in drinking water. In all three surveys, the detection frequency of any gasoline hydrocarbon was less than the detection frequency of MTBE. No concentration of MTBE in source water exceeded the lower limit of U.S. Environmental Protection Agency's Drinking-Water Advisory of 20 ?g/L (micrograms per liter). One concentration of MTBE in ground water exceeded 20 ?g/L, and 0.9 percent of drinking-water samples exceeded 20 ?g/L. The overall detection frequency of MTBE relative to other widely used VOCs indicates that MTBE is an important concern with respect to ground-water management. The probability of detecting MTBE was strongly associated with population density, use of MTBE in gasoline, and recharge, and weakly associated with density of leaking underground storage tanks, soil permeability, and aquifer consolidation. Only concentrations of MTBE above 0.5 ?g/L were associated with dissolved oxygen. Ground water underlying areas with high population density, ground water underlying areas where MTBE is used as a gasoline oxygenate, and ground water underlying areas with high recharge has a greater probability of MTBE contamination. Ground water from public-supply wells and shallow ground water underlying urban land-use areas has a greater probability of MTBE contamination compared to ground water from domestic wells and ground water underlying rural land-use areas.

  7. Hydrogen Atom Reactivity toward Aqueous tert-Butyl Alcohol

    SciTech Connect

    Lymar S. V.; Schwarz, H.A.

    2012-02-09

    Through a combination of pulse radiolysis, purification, and analysis techniques, the rate constant for the H + (CH{sub 3}){sub 3}COH {yields} H{sub 2} + {sm_bullet}CH{sub 2}C(CH{sub 3}){sub 2}OH reaction in aqueous solution is definitively determined to be (1.0 {+-} 0.15) x 10{sup 5} M{sup -1} s{sup -1}, which is about half of the tabulated number and 10 times lower than the more recently suggested revision. Our value fits on the Polanyi-type, rate-enthalpy linear correlation ln(k/n) = (0.80 {+-} 0.05){Delta}H + (3.2 {+-} 0.8) that is found for the analogous reactions of other aqueous aliphatic alcohols with n equivalent abstractable H atoms. The existence of such a correlation and its large slope are interpreted as an indication of the mechanistic similarity of the H atom abstraction from {alpha}- and {beta}-carbon atoms in alcohols occurring through the late, product-like transition state. tert-Butyl alcohol is commonly contaminated by much more reactive secondary and primary alcohols (2-propanol, 2-butanol, ethanol, and methanol), whose content can be sufficient for nearly quantitative scavenging of the H atoms, skewing the H atom reactivity pattern, and explaining the disparity of the literature data on the H + (CH{sub 3}){sub 3}COH rate constant. The ubiquitous use of tert-butyl alcohol in pulse radiolysis for investigating H atom reactivity and the results of this work suggest that many other previously reported rate constants for the H atom, particularly the smaller ones, may be in jeopardy.

  8. 40 CFR 721.4925 - Methyl n-butyl ketone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Methyl n-butyl ketone. 721.4925... Substances § 721.4925 Methyl n-butyl ketone. (a) Chemical substance and significant new use subject to reporting. (1) The chemical substance methyl n-butyl ketone, CAS Number 591-78-6, is subject to...

  9. TOXICITY OF METHYL-TERT BYTYL ETHER (MTBE) TO PLANTS (AVENA SATIVA, ZEA MAYS, TRITICUM AESTIVUM, AND LACTUCA SATIVA)

    EPA Science Inventory

    Effects of Methyl tert-butyl ether (MTBE) on the germination of seeds and growth of the plant were studied in some laboratory experiments. Test plants were wild oat (Avena sative), sweet corn (Zea mays), wheat (Triticum aestivum), and lettuce (Lactuca sativa). Seed germination,...

  10. Stability testing of the plastics additives 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-ethoxy-2-ethyloxanilide (tinuvin 312) and 2,2'-methylenebis(4-methyl-t-tert-butyl phenol) in aqueous and fatty food simulants.

    PubMed

    Spyropoulos, D V

    1998-04-01

    The stability of five additives used in the manufacture of plastics materials intended to be in contact with foodstuffs was tested in two EU aqueous food simulants (3% acidic acid and 15% ethanol), in olive oil and in two alternative fatty food simulants (95% ethanol and isooctane) under various conditions of temperature and time established for migration testing. The additives were the following: 2,4-dihydroxybenzophenone, 2-2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-ethoxy-2-ethyloxanilide and 2,2'-methylenebis(4-methyl-6-tert-butyl phenol). The additives were spiked into the simulants at their anticipated Specific Migration Limit (SML) and submitted to time-temperature conditions used in the migration testing. The test samples were analysed against fresh samples of the additives spiked at the same concentration just before the analysis. All samples were analysed with HPLC, using an ODS2 column and mobile phase of methanol-water or acetonitrile-water. The results were statistically evaluated by applying a two-tailed F-test (at 95% confidence level) to the variances and onetailed t-test (at 90% confidence level) to the means of the control and the test samples. The statistical evaluation of the results showed that the additives were stable in all simulants within the statistical allowances. Only the 2.2'-methylenebis(4-methyl-6-tert-butyl phenol) showed a loss of about 20% in olive oil and 17% in 3% aqueous acetic acid. The results of the study will be used by the Commission, DG III-C-I. to help to determine whether legislative restrictions in the additives Directive should be applied to the finished material or article (QM) or to migration to simulants (SML). PMID:9666896

  11. 2,6-Di-tert-butyl-4-(3-chloro-2-hy­droxy­prop­yl)phenol

    PubMed Central

    Asgarova, Ayten R.; Maharramov, Abel M.; Khalilov, Ali N.; Gurbanov, Atash V.; Ng, Seik Weng

    2011-01-01

    In the title 2-propanol derivative, C17H27ClO2, the two tert-butyl groups both have one methyl C atom lying in the plane of the aromatic ring. In the crystal, the phenol group forms a hydrogen bond to the hy­droxy O atom belonging to the alkyl substituent of an adjacent mol­ecule, forming a chain along the ac diagonal. The Cl atom is disordered over two positions in a 0.73?(4):0.27?(4) ratio. PMID:21754133

  12. 2,6-Di-tert-butyl-4-(3-chloro-2-hy-droxy-prop-yl)phenol.

    PubMed

    Asgarova, Ayten R; Maharramov, Abel M; Khalilov, Ali N; Gurbanov, Atash V; Ng, Seik Weng

    2011-04-01

    In the title 2-propanol derivative, C(17)H(27)ClO(2), the two tert-butyl groups both have one methyl C atom lying in the plane of the aromatic ring. In the crystal, the phenol group forms a hydrogen bond to the hy-droxy O atom belonging to the alkyl substituent of an adjacent mol-ecule, forming a chain along the ac diagonal. The Cl atom is disordered over two positions in a 0.73?(4):0.27?(4) ratio. PMID:21754133

  13. 27 CFR 21.101 - tert-Butyl alcohol.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... Colorless. (c) Distillation range. When 100 ml of tertiary butyl alcohol are distilled, none should distill....1 percent tertiary butyl alcohol in ethyl alcohol in a test tube. Add 2 ml of Denige's...

  14. Occurrence and distribution of methyl tert-butyl ether and other volatile organic compounds in drinking water in the Northeast and Mid-Atlantic regions of the United States, 1993-98

    USGS Publications Warehouse

    Grady, S.J.; Casey, G.D.

    2001-01-01

    Data on volatile organic compounds (VOCs) in drinking water supplied by 2,110 randomly selected community water systems (CWSs) in 12 Northeast and Mid-Atlantic States indicate 64 VOC analytes were detected at least once during 1993-98. Selection of the 2,110 CWSs inventoried for this study targeted 20 percent of the 10,479 active CWSs in the region and represented a random subset of the total distribution by State, source of water, and size of system. The data include 21,635 analyses of drinking water collected for compliance monitoring under the Safe Drinking Water Act; the data mostly represent finished drinking water collected at the pointof- entry to, or at more distal locations within, each CWS?s distribution system following any watertreatment processes. VOC detections were more common in drinking water supplied by large systems (serving more than 3,300 people) that tap surface-water sources or both surface- and groundwater sources than in small systems supplied exclusively by ground-water sources. Trihalomethane (THM) compounds, which are potentially formed during the process of disinfecting drinking water with chlorine, were detected in 45 percent of the randomly selected CWSs. Chloroform was the most frequently detected THM, reported in 39 percent of the CWSs. The gasoline additive methyl tert-butyl ether (MTBE) was the most frequently detected VOC in drinking water after the THMs. MTBE was detected in 8.9 percent of the 1,194 randomly selected CWSs that analyzed samples for MTBE at any reporting level, and it was detected in 7.8 percent of the 1,074 CWSs that provided MTBE data at the 1.0-?g/L (microgram per liter) reporting level. As with other VOCs reported in drinking water, most MTBE concentrations were less than 5.0 ?g/L, and less than 1 percent of CWSs reported MTBE concentrations at or above the 20.0-?g/L lower limit recommended by the U.S. Environmental Protection Agency?s Drinking-Water Advisory. The frequency of MTBE detections in drinking water is significantly related to high- MTBE-use patterns. Detections are five times more likely in areas where MTBE is or has been used in gasoline at greater than 5 percent by volume as part of the oxygenated or reformulated (OXY/RFG) fuels program. Detection frequencies of the individual gasoline compounds (benzene, toluene, ethylbenzene, and xylenes (BTEX)) were mostly less than 3 percent of the randomly selected CWSs, but collectively, BTEX compounds were detected in 8.4 percent of CWSs. BTEX concentrations also were low and just three drinkingwater samples contained BTEX at concentrations exceeding 20 ?g/L. Co-occurrence of MTBE and BTEX was rare, and only 0.8 percent of CWSs reported simultaneous detections of MTBE and BTEX compounds. Low concentrations and cooccurrence of MTBE and BTEX indicate most gasoline contaminants in drinking water probably represent nonpoint sources. Solvents were frequently detected in drinking water in the 12-State area. One or more of 27 individual solvent VOCs were detected at any reporting level in 3,080 drinking-water samples from 304 randomly selected CWSs (14 percent) and in 206 CWSs (9.8 percent) at concentrations at or above 1.0 ?g/L. High co-occurrence among solvents probably reflects common sources and the presence of transformation by-products. Other VOCs were relatively rarely detected in drinking water in the 12-State area. Six percent (127) of the 2,110 randomly selected CWSs reported concentrations of 16 VOCs at or above drinking-water criteria. The 127 CWSs collectively serve 2.6 million people. The occurrence of VOCs in drinking water was significantly associated (p<0.0001) with high population- density urban areas. New Jersey, Massachusetts, and Rhode Island, States with substantial urbanization and high population density, had the highest frequency of VOC detections among the 12 States. More than two-thirds of the randomly selected CWSs in New Jersey reported detecting VOC concentrations in drinking water at or above 1

  15. The oxidation of 2,6-di-tert-butyl-4-methylphenol

    USGS Publications Warehouse

    Yohe, G.R.; Dunbar, J.E.; Pedrotti, R.L.; Scheidt, F.M.; Lee, F.G.H.; Smith, E.C.

    1956-01-01

    The products formed in the oxidation of 2,6-di-tert-butyl-4-methylphenol with oxygen and sodium hydroxide at about 100?? are 3,5-di-tert-butyl-4-hydroxybenzaldehyde, trimethylacetic acid, an acidic compound C14H22O3, and probably 2,6-di-tert-butylbenzoquinone (which was actually isolated in the similar oxidation of the above-named benzaldehyde), in addition to compounds previously reported. Some of the properties of C14H22O3 are given, and the oxidation of it to 2,3-di-tert-butylsuccinic anhydride is described, but assignment of structure is reserved pending the completion of more experimental work.

  16. Regioisomer-Free C 4h ?-Tetrakis(tert-butyl)metallo-phthalocyanines: Regioselective Synthesis and Spectral Investigations.

    PubMed

    Iida, Norihito; Tanaka, Kenta; Tokunaga, Etsuko; Takahashi, Hiromi; Shibata, Norio

    2015-04-01

    Metal ?-tetrakis(tert-butyl)phthalocyanines are the most commonly used phthalocyanines due to their high solubility, stability, and accessibility. They are commonly used as a mixture of four regioisomers, which arise due to the tert-butyl substituent on the ?-position, and to the best of our knowledge, their regioselective synthesis has yet to be reported. Herein, the C 4h -selective synthesis of ?-tetrakis(tert-butyl)metallophthalocyanines is disclosed. Using tetramerization of ?-trialkylsilyl phthalonitriles with metal salts following acid-mediated desilylation, the desired metallophthalocyanines were obtained in good yields. Upon investigation of regioisomer-free zinc ?-tetrakis(tert-butyl)phthalocyanine using spectroscopy, the C 4h single isomer described here was found to be distinct in the solid state to zinc ?-tetrakis(tert-butyl)phthalocyanine obtained by a conventional method. PMID:25969805

  17. Studies on the Conformational Landscape of Tert-Butyl Acetate Using Microwave Spectroscopy and Quantum Chemical Calculations

    NASA Astrophysics Data System (ADS)

    Zhao, YueYue; Mouhib, Halima; Li, Guohua; Stahl, Wolfgang; Kleiner, Isabelle

    2014-06-01

    The tert-Butyl acetate molecule was studied using a combination of quantum chemical calculations and molecular beam Fourier transform microwave spectroscopy in the 9 to 14 GHz range. Due to its rather rigid frame, the molecule possesses only two different conformers: one of Cs and one of C1 symmetry. According to ab initio calculations, the Cs conformer is 46 kJ/mol lower in energy and is the one observed in the supersonic jet. We report on the structure and dynamics of the most abundant conformer of tert-butyl acetate, with accurate rotational and centrifugal distortion constants. Additionally, the barrier to internal rotation of the acetyl methyl group was determined. Splittings due to the internal rotation of the methyl group of up to 1.3 GHz were observed in the spectrum. Using the programs XIAM and BELGI-Cs, we determine the barrier height to be about 113 cm-1 and compare the molecular parameters obtained from these two codes. Additionally, the experimental rotational constants were used to validate numerous quantum chemical calculations. This study is part of a larger project which aims at determining the lowest energy conformers of organic esters and ketones which are of interest for flavor or perfume synthetic applications Project partly supported by the PHC PROCOPE 25059YB.

  18. tert-Butyl Sulfoxide as a Starting Point for the Synthesis of Sulfinyl Containing Compounds.

    PubMed

    Wei, Juhong; Sun, Zhihua

    2015-11-01

    Sulfoxides bearing a tert-butyl group can be activated using N-bromosuccinimide (NBS) under acidic conditions and then subsequently treated with a variety of nitrogen, carbon, or oxygen nucleophiles to afford a wide range of the corresponding sulfinic acid amides, new sulfoxides, and sulfinic acid esters. PMID:26502058

  19. Palladium/Tris(tert-butyl)phosphine-Catalyzed Suzuki Cross-Couplings in the Presence of Water

    E-print Network

    Lou, Sha

    Dipalladiumtris(dibenzylideneacetone)/tris(tert-butyl)phosphonium tetrafluoroborate/potassium fluoride dihydrate [Pd2(dba)3/[HP(t-Bu)3]BF4/KF?2?H2O] serves as a mild, robust, and user-friendly method for the efficient ...

  20. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  1. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  2. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  3. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  4. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  5. hTERT promoter methylation in pituitary adenomas.

    PubMed

    Köchling, Michaela; Ewelt, Christian; Fürtjes, Gina; Peetz-Dienhart, Susanne; Koos, Björn; Hasselblatt, Martin; Paulus, Werner; Stummer, Walter; Brokinkel, Benjamin

    2016-01-01

    Telomerase reverse transcriptase (TERT) expression is a hallmark in tumorigenesis and upregulated due to mutations and methylation of the human (h)TERT promoter. As mutations are rare but methylation is common in pituitary adenomas (PA), we determined promoter methylation and its clinical impact in 85 primary and 15 recurrent PA by methylation-specific PCR. 40 females (47 %) and 45 males (53 %) with a median age of 53 years harboring micro-, macro-, and giant adenomas in 12, 82, and 6 % were included (prolactinomas, corticotroph, somatotroph, gonadotroph, thyreotroph, plurihormonal, and null cell adenomas in 11, 18, 10, 29, 1, 10, and 21 %, respectively). In primary diagnosed tumors, methylation rate was 27 % and higher in males than in females (40 vs. 13 %, p = 0.001) after uni- and multivariate analyses. Methylation differed among PA subtypes (0-42 %, p = n.s.) and was not significantly correlated with tumor size, cavernous sinus invasion, or serum hormone levels. Ki67 labeling index and recurrence (N = 16, 19 %) were independent of methylation. In recurrent tumors, methylation was similar to primary PA (N = 5/15, 33 %) and remained unchanged along follow-up. Thus, while being commonly observed in PA, hTERT promoter methylation is stable along follow-up and independent of most clinical variables, PA subtype, proliferation, and without prognostic value. PMID:26390879

  6. 40 CFR 721.10326 - 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate...2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate...2-propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl...

  7. 40 CFR 721.10326 - 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate...2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate...2-propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl...

  8. Thin PDMS Films Using Long Spin Times or Tert-Butyl Alcohol as a Solvent

    PubMed Central

    Koschwanez, John H.; Carlson, Robert H.; Meldrum, Deirdre R.

    2009-01-01

    Thin polydimethylsiloxane (PDMS) films are frequently used in “lab on a chip” devices as flexible membranes. The common solvent used to dilute the PDMS for thin films is hexane, but hexane can swell the underlying PDMS substrate. A better solvent would be one that dissolves uncured PDMS but doesn't swell the underlying substrate. Here, we present protocols and spin curves for two alternatives to hexane dilution: longer spin times and dilution in tert-butyl alcohol. The thickness of the PDMS membranes under different spin speeds, spin times, and PDMS concentrations was measured using an optical profilometer. The use of tert-butyl alcohol to spin thin PDMS films does not swell the underlying PDMS substrate, and we have used these films to construct multilayer PDMS devices. PMID:19238212

  9. 2,6-Di-tert-butyl-4-(morpholinometh­yl)­phenol monohydrate

    PubMed Central

    Zeng, Tao; Ren, Wan-Zhong

    2008-01-01

    In the title compound, C19H31NO2·H2O, the morpholine ring adopts a chair conformation, while the phenolic hydroxyl group is sterically hindered by the adjacent tert-butyl groups. The crystal structure is stabilized by a number of O—H?O, O—H?N and C—H?O hydrogen-bonding inter­actions, involving both the organic and the solvent mol­ecules. PMID:21201434

  10. 2,6-Di-tert-butyl-4-(morpholinometh-yl)-phenol monohydrate.

    PubMed

    Zeng, Tao; Ren, Wan-Zhong

    2008-01-01

    In the title compound, C(19)H(31)NO(2)·H(2)O, the morpholine ring adopts a chair conformation, while the phenolic hydroxyl group is sterically hindered by the adjacent tert-butyl groups. The crystal structure is stabilized by a number of O-H?O, O-H?N and C-H?O hydrogen-bonding inter-actions, involving both the organic and the solvent mol-ecules. PMID:21201434

  11. Methyl-tertiary-butyl-ether (MTBE) misclassified.

    PubMed

    Mehlman, M A

    2001-05-01

    Methyl-tertiary-butyl-ether (MTBE) was introduced into motor fuels in 1992 to reduce carbon monoxide automotive emissions in areas where the National Ambient Air Quality Standards for CO were exceeded. At a meeting of the National Toxicology Program's Board of Scientific Counselors (2-3 December 1998), data were presented showing that exposure to MTBE caused increased incidence of liver tumors, renal adenomas, carcinomas and interstitial cell adenomas of the testes in male, and lymphomas and leukemia in female CD1 mice [National Toxicology Program, 1998]. Despite this evidence, the NTP Board defeated a motion to list MTBE as "Reasonably anticipated to be a human carcinogen" by a vote of 6 to 5. This decision directly contravenes rules and procedures previously established by NTP for assessing carcinogenicity of chemical compounds. Good public health policy dictates that the NTP Board conduct another review of MTBE with proper consideration of the criteria that have been established for listing agents as carcinogens. Millions of Americans who are exposed daily to this chemical deserve an unbiased evaluation of carcinogenic agents being introduced into the environment. PMID:11333412

  12. Oxidation of 2,6-di-tert-butyl-4-methylphenol. The structure of C14H22O3

    USGS Publications Warehouse

    Yohe, G.R.; Dunbar, J.E.; Lansford, M.W.; Pedrotti, R.L.; Scheidt, F.M.; Lee, F.G.H.; Smith, E.C.

    1959-01-01

    The acidic compound C14H22O3, previously reported without assignment of structure as an oxidation product of 2,6-di-tert-butyl-4-methylphenol, is now believed to be DL-trans-5,6-di-tert-butyl-2-hydroxy-1,4-diketo-2-cyclohexene (I). Chemical properties are described and infrared spectra are presented in support of this structure. This structure is of interest in relation to the problem of the existence of o-di-tert-alkylbenzene derivatives. The relatively easy racemization of optically active I suggests that its completely enolized form, 5,6-di-tert-butyl-1,2,4-trihydroxybenzene, is capable of transitory existence.

  13. Synthesis and bioevaluation of 4-chloro-2-tert-butyl-5-[2-[[1-[2-[(18) F]fluroethyl]-1H-1,2,3-triazol-4-yl]methyl]phenylmethoxy]-3(2H)-pyridazinone as potential myocardial perfusion imaging agent with PET.

    PubMed

    Mou, Tiantian; Zhao, Zuoquan; You, Linyi; Wang, Qian; Fang, Wei; Lu, Jie; Peng, Cheng; Zhang, Xianzhong

    2015-06-30

    This study reports the synthesis and characterization of 4-chloro-2-tert-butyl-5-[2-[[1-[2-[(18) F]fluroethyl]-1H-1,2,3-triazol-4-yl]methyl]phenylmethoxy]-3(2H)-pyridazinone ([(18) F]Fmp2) for myocardial perfusion imaging (MPI). The tosylate precursor and non-radioactive compound [(19) F]Fmp2 were synthesized and characterized by infrared, (1) H-NMR, (13) C-NMR, and mass spectra (MS). The radiotracer [(18) F]Fmp2 was obtained by one-step nucleophilic substitution of tosyl with (18) F, and evaluated as an MPI agent in vitro and in vivo. Starting from [(18) F]KF/K222 solution, the typical decay-corrected radiochemical yield (RCY) was 38?±?8.8% with high radiochemical purity (>98%). The specific activity was calculated as 10?GBq/µmol at the end of synthesis determined by HPLC analysis. In the mice biodistribution, [(18) F]Fmp2 showed very high initial heart uptake (53.35?±?5.47 %ID/g at 2?min after injection) and remarkable retention. The heart/liver, heart/lung, and heart/blood ratios were 7.98, 8.20, and 53.13, respectively at 2?min post-injection. In the Positron Emission Tomography (PET) imaging study of Chinese mini-swine, the standardized uptake value of the liver decreased modestly during the 2?h post-injection, while the heart uptake and heart/liver ratios continued to increase with time. [(18) F]Fmp2 exhibited good stability, high heart uptake and low lung uptake in mice and Chinese mini-swine. It may be worthy of further modification to improve liver clearance for MPI in the future. PMID:26094722

  14. (2,6-Bis{5-amino-3-tert-butyl-4-[(3-methyl-1,2,4-thia­diazol-5-yl)diazen­yl]-1H-pyrazol-1-yl}-4-oxo-1,4-dihydro-1,3,5-triazin-1-ido)methanol(phenol)sodium phenol tetra­solvate

    PubMed Central

    Shibata, Hiroki; Mizuguchi, Jin

    2010-01-01

    The title compound, [Na(C23H28N17OS2)(CH3OH)(C6H5OH)]·4C6H5OH, is a five-coordinate NaI complex. The Na+ cation is bound to three N atoms of the triazinide ligand, two from each pyrazole ring and one from the central deprotonated triazine ring system. O atoms from a methanol and a phenol mol­ecule complete the five-coordinate NaN3O2 coordination environment. The asymmetric unit also includes three complete and two half phenol mol­ecules, four of which are hydrogen bonded to the N atoms of the thia­diazole ring. Two of the phenol solvent mol­ecules are disordered over two discrete inversion centres. The triazinide ligand is essentially planar (mean deviation from the least-squares plane = 0.0524?Å), with the methyl groups of the tert-butyl substituents on the pyrazole rings located above and below the plane. The planarity of this system is further assisted by the formation of four intra­molecular N—H?N hydrogen bonds between the N—H bonds of both amino groups on the pyrazole rings and the N atoms of the triazine ring and also from each of the adjacent diazene (–N=N–) bonds. The highly polar mol­ecules are stacked along the a axis through the central Na atom sandwiched by two kinds of alternating inter­molecular hydrogen bonds: O(carbon­yl)?H—O(methanol)/Na/O—H(phenol)?O(carbon­yl). These inter­actions form two polymer chains per mol­ecule. PMID:21580548

  15. (2,6-Bis{5-amino-3-tert-butyl-4-[(3-methyl-1,2,4-thia-diazol-5-yl)diazen-yl]-1H-pyrazol-1-yl}-4-oxo-1,4-dihydro-1,3,5-triazin-1-ido)methanol(phenol)sodium phenol tetra-solvate.

    PubMed

    Shibata, Hiroki; Mizuguchi, Jin

    2010-01-01

    The title compound, [Na(C(23)H(28)N(17)OS(2))(CH(3)OH)(C(6)H(5)OH)]·4C(6)H(5)OH, is a five-coordinate Na(I) complex. The Na(+) cation is bound to three N atoms of the triazinide ligand, two from each pyrazole ring and one from the central deprotonated triazine ring system. O atoms from a methanol and a phenol mol-ecule complete the five-coordinate NaN(3)O(2) coordination environment. The asymmetric unit also includes three complete and two half phenol mol-ecules, four of which are hydrogen bonded to the N atoms of the thia-diazole ring. Two of the phenol solvent mol-ecules are disordered over two discrete inversion centres. The triazinide ligand is essentially planar (mean deviation from the least-squares plane = 0.0524?Å), with the methyl groups of the tert-butyl substituents on the pyrazole rings located above and below the plane. The planarity of this system is further assisted by the formation of four intra-molecular N-H?N hydrogen bonds between the N-H bonds of both amino groups on the pyrazole rings and the N atoms of the triazine ring and also from each of the adjacent diazene (-N=N-) bonds. The highly polar mol-ecules are stacked along the a axis through the central Na atom sandwiched by two kinds of alternating inter-molecular hydrogen bonds: O(carbon-yl)?H-O(methanol)/Na/O-H(phenol)?O(carbon-yl). These inter-actions form two polymer chains per mol-ecule. PMID:21580548

  16. Characterization of tert-butyl alcohol binding to alpha2u-globulin in F-344 rats.

    PubMed

    Williams, T M; Borghoff, S J

    2001-08-01

    tert-Butyl alcohol (TBA) is widely used in the manufacturing of certain perfumes, cosmetics, drugs, paint removers, methyl tert-butyl ether (MTBE), and industrial solvents. In both rodents and humans, TBA is a major metabolite of MTBE, an oxygenated fuel additive. Chronic TBA exposure causes protein droplet nephropathy, alpha2u-globulin (alpha2u) accumulation, renal cell proliferation, and with chronic exposure, renal tumors in male, but not female, rats. These effects suggest an alpha2u-mediated mechanism for renal tumors. The objective of the present study was to determine whether TBA or its metabolites bind to alpha2u. Mature male and female F-344 rats were administered a single gavage dose of 500 mg/kg TBA, 500 mg/kg (14)C-TBA, or corn oil. TBA equivalents/gram or ml of tissue in the male rat kidney, liver, and blood were higher than the levels measured in female rat tissue 12 h after (14)C-TBA administration. Gel filtration and anion-exchange chromatography demonstrated that (14)C-TBA-derived radioactivity co-eluted with alpha2u from male kidney cytosol. Protein dialysis studies demonstrated that the interaction between (14)C-TBA-derived radioactivity and alpha2u was reversible. Incubations of the low-molecular-weight protein fraction (LMWPF) isolated from (14)C-TBA-treated male rat kidneys with d-limonene oxide (a chemical with a high affinity to alpha2u) demonstrated that (14)C-TBA-derived radioactivity was displaced. Gas chromatography-mass spectrometry analysis confirmed that TBA was present in this LMWPF fraction. These results demonstrate that TBA interacts with alpha2u, which explains the accumulation of alpha2u in the male rat kidney following TBA exposure. PMID:11452135

  17. The role of dopant geometry in the photoinduced formation of radical pairs in crystals of 2,6-di-tert-butyl-4-methylphenol and 2,6-di-tert-butylphenol

    NASA Astrophysics Data System (ADS)

    Lazarev, Georgii G.; Kuskov, Vladimir L.; Lara, Francisco; García, Federico; Rieker, Anton; Tordo, Paul

    1993-09-01

    Radical pairs are formed by photolysis of single crystals of 2,6-di-tert-butyl-4-methylphenol (ionol) ( 1) or 2,6-di-tert-butyl-phenol ( 2), doped by several different molecules, and investigated by the EPR method. A possible two-hydrogen-atom transfer is discussed as the photochemical act.

  18. Mechanism of dehydration of tert-butyl alcohol in phosphoric acid solutions

    SciTech Connect

    Obraztsov, P.A.; Vinnik, M.I.

    1987-04-01

    The kinetic regularities of dehydration of tert-butyl alcohol on deposited phosphoric acid catalyst were studied by the pulsed gas-chromatographic method. Dehydration rate constants at 70/sup 0/C were determined in the range of H/sub 3/PO/sub 4/ concentrations of 50-80.4 wt. %. A dehydration mechanism was proposed from the dependence of this constant on the acidity of the medium. This includes the formation of a reactive complex consisting of a molecule of an unprotonated alcohol, a molecule of undissociated H/sub 3/PO/sub 4/ and a molecule of water.

  19. The Epoxidation of 2,5-Di-tert-butyl-1,4-benzoquinone: A Consecutive Reaction for the Physical Chemistry Laboratory.

    ERIC Educational Resources Information Center

    Hairfield, E. M.; And Others

    1985-01-01

    Reports a consecutive first-order reaction for which the concentrations of reactant, intermediate, and products can be determined simulataneously. This reaction is the epoxidation of 2,5-di-tert-butyl-1,4-benzoquinone (I) by alkaline hydroperoxidation using tert-butyl hydroperoxide and benzyltrimethylammonium hydroxide (Triton B) catalyst.…

  20. Radical pairs during photolysis of an iminoquinone in single crystals of 2,6-di-tert-butyl-4-methylphenol

    NASA Astrophysics Data System (ADS)

    Lazarev, Georgii G.; Lara, Francisco; Garcia, Federico; Rieker, Anton

    1992-10-01

    The formation of radical pairs with a dipole—dipole splitting constant D = 12.2 ± 0.2 mT upon photolysis of single crystals of 2,6-di-tert-butyl-4-methylphenol doped with 10 -3 M 2,6-di-tert-butyl-1-imino- p-quinone was studied by EPR spectroscopy in the temperature range between 77 and 140 K. The mechanism of the formation of the radical pairs is discussed in terms of a hydrogen-atom phototransfer from the phenol to the iminoquinone.

  1. 40 CFR 721.10326 - 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ester, polymer with butyl 2-propenoate, ethyl 2-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2... 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2-propenoate (1:2), 2,2'-(1,2-diazenediyl)bis - and...

  2. Substituted 2,2?-bipyridines by nickel-catalysis: 4,4?-di-tert-butyl-2,2?-bipyridine

    PubMed Central

    Buonomo, Joseph A.; Everson, Daniel A.; Weix, Daniel J.

    2014-01-01

    A simple, ligand-free synthesis of the important bipyridyl ligand 4,4?-di-tert-butyl-2,2?-bipyridine is presented. 5,5?-bis(trifluoromethyl)-2,2?-bipyridine is also synthesized by the same protocol. The syntheses efficiently couple the parent 2-chlorpyridies by a nickel-catalyzed dimerization with manganese powder as the terminal reductant. PMID:25221358

  3. Inhibition of radical reactions for an improved potassium tert-butoxide-promoted (11) C-methylation strategy for the synthesis of ?-(11) C-methyl amino acids.

    PubMed

    Suzuki, Chie; Kato, Koichi; Tsuji, Atsushi B; Zhang, Ming-Rong; Arano, Yasushi; Saga, Tsuneo

    2015-03-01

    ?-(11) C-Methyl amino acids are useful tools for biological imaging studies. However, a robust procedure for the labeling of amino acids has not yet been established. In this study, the (11) C-methylation of Schiff-base-activated ?-amino acid derivatives has been optimized for the radiosynthesis of various ?-(11) C-methyl amino acids. The benzophenone imine analog of methyl 2-amino butyrate was (11) C-methylated with [(11) C]methyl iodide following its initial deprotonation with potassium tert-butoxide (KOtBu). The use of an alternative base such as tetrabutylammonium fluoride, triethylamine, and 1,8-diazabicyclo[5.4.0]undec-7-ene did not result in the (11) C-methylated product. Furthermore, the KOtBu-promoted (11) C-methylation of the Schiff-base-activated amino acid analog was enhanced by the addition of 1,2,4,5-tetramethoxybenzene or 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and inhibited by the addition of 1,10-phenanthroline. These results suggest that inhibition of radical generation induced by KOtBu improves the ?-(11) C-methylation of the Schiff-base-activated amino acids. The addition of a mixture of KOtBu and TEMPO to a solution of Schiff-base-activated amino acid ester and [(11) C]methyl iodide provided optimal results, and the tert-butyl ester and benzophenone imine groups could be readily hydrolyzed to give the desired ?-(11) C-methyl amino acids with a high radiochemical conversion. This strategy could be readily applied to the synthesis of other ?-(11) C-methyl amino acids. PMID:25690316

  4. Photoelectric conversion and electrochromic properties of lutetium tetrakis(tert-butyl)bisphthalocyaninate

    SciTech Connect

    Hu, Andrew Teh; Hu Tenyi; Liu Lungchang

    2003-12-10

    Both photoelectric and electrochromic effects on lutetium tetrakis(tert-butyl)bisphthalocyaninate (Lu(TBPc){sub 2}) have been carried out in this study. Lu(TBPc){sub 2} is known for its electrochromic performance, but its photoelectric effect has not mentioned in the literature. The electrochromic properties of Lu(TBPc){sub 2} have been measured by cyclic voltammetry (CV) and UV-Vis spectrometer at the same time. It takes less than 1.5 s for the color to change from red to green under 0.9 V. Its cycle life is at least over 500 times. Furthermore, we also investigate its photoelectric conversion properties. Its photoelectric cell exhibits a positive photo-electricity conversion effect with a short-circuit photocurrent (46.4 {mu}A/cm{sup 2}) under illumination of white light (1.201 mW/cm{sup 2})

  5. Features of the spectral dependences of transmittance of organic semiconductors based on tert-butyl substituted lutetium phthalocyanine molecules

    SciTech Connect

    Belogorokhov, I. A.; Tikhonov, E. V.; Dronov, M. A.; Belogorokhova, L. I.; Ryabchikov, Yu. V.; Tomilova, L. G.; Khokhlov, D. R.

    2011-11-15

    Vibronic properties of organic semiconductors based on tert-butyl substituted phthalocyanine lutetium diphthalocyanine molecules are studied by IR and Raman spectroscopy. It is shown that substitution of several carbon atoms in initial phthalocyanine (Pc) ligands with {sup 13}C isotope atoms causes a spectral shift in the main absorption lines attributed to benzene, isoindol, and peripheral C-H groups. A comparison of spectral characteristics showed that the shift can vary from 3 to 1 cm{sup -1}.

  6. Aberrant methylation of the TERT promoter in esophageal squamous cell carcinoma.

    PubMed

    Deng, Jiaying; Zhou, Daizhan; Zhang, Junhua; Chen, Yun; Wang, Chunyu; Liu, Yun; Zhao, Kuaile

    2015-12-01

    A recent study indicated that upstream of the transcription start site (UTSS) hypermethylation of the telomerase reverse transcriptase (TERT) gene was associated with tumor progression and poor prognosis in pediatric brain tumors. The potential for methylation-mediated regulation of the UTSS region of the TERT gene in esophageal squamous cell carcinoma (ESCC) has not yet been investigated. Here, TERT methylation was investigated in tumor and paired adjacent non-cancerous tissues (ANT) from 185 ESCC patients, and the expression of TERT was investigated in 26 tumors paired with ANTs selected from the same cohort. The methylation level of TERT was analyzed in three different regions: region 1, region 2, and the UTSS region. Comparison and correlation of methylation level and clinical features were analyzed in the abovementioned regions. The results showed that the methylation level of TERT was significantly elevated in the tumor relative to the ANT in ESCC. TERT RNA expression was significantly reduced in primary tumors. Tumor stage was the major determinant of survival. The UTSS region may not be an accessible biomarker for ESCC. PMID:26669682

  7. Emulsion Polymerization of Butyl Acrylate: Spin Trapping and EPR Study

    NASA Technical Reports Server (NTRS)

    Kim, S.; Westmoreland, D.

    1994-01-01

    The propagating radical in the emulsion polymerization reaction of butyl acrylate was detected by Electron Paramagnetic Resonance spectroscopy using two spin trapping agents, 2-methyl-2nitrosopropane and alpha -N-tert-butylnitrone.

  8. Impact of tert-butyl alcohol on crystallization kinetics of gemcitabine hydrochloride in frozen aqueous solutions.

    PubMed

    Munjal, Bhushan; Bansal, Arvind K

    2015-01-01

    The effect of tert-butyl alcohol (TBA) on isothermal crystallization kinetics of gemcitabine hydrochloride (GHCl) in frozen aqueous solutions was assessed by cold-stage microscopy. Addition of TBA (0%-5%, w/w) increased the value of Johnson-Mehl-Avrami rate constant (1.3-33.3 h?¹) and reduced the Avrami exponent (2.5-1.0). Thermodynamic parameters [enthalpy (?H(‡)), entropy (?S(‡)), and free energy (?G(‡)) of activation], calculated using Arrhenius and Eyring-Polanyi equations, established that TBA (2%, w/w) accelerated GHCl crystallization by reducing its ?H(‡) (53.9 cf. 96.5 kJ/mol?¹) and ?G(‡) (68.5 cf. 74.9 kJ/mol?¹). Further, to explore insights into the effect of TBA on nucleation and crystal growth of GHCl, crystallization kinetics data were deconvolved using Finke-Watzky model. This revealed that addition of TBA decreased ?H(‡) of nucleation and increased ?S(‡) of crystal growth, thereby reducing ?G(‡) of nucleation and crystal growth by 11.7% and 4.2%, respectively. Finkey-Watzky model also predicted a reduction in the crystal size upon TBA addition, which was confirmed by comparing particle size of GHCl lyophilized in the presence and absence of TBA. In conclusion, TBA reduces ?G(‡) of nucleation and crystal growth in a differential manner, thereby enhancing the crystallization kinetics of GHCl and affecting its morphological features. PMID:25393155

  9. Entanglement Dynamics in Miscible Polyisoprene / Poly(p-tert-butyl styrene) Blends

    NASA Astrophysics Data System (ADS)

    Watanabe, Hiroshi

    2011-03-01

    Viscoelastic and dielectric behavior was examined for well entangled, miscible blends of high- M cis-polyisoprene (PI) and poly(p-tert-butyl styrene) (PtBS). The dielectric data of the blends, reflecting the global motion of the PI chains having the type-A dipoles, indicated that PI and PtBS were the fast and slow components therein. At high temperatures T , the blends exhibited two-step entanglement plateau. The high frequency (?) plateau height was well described by a simple mixing rule of the entanglement length based on the number fraction of the Kuhn segments. At low T , the blend exhibited the Rouse-like power-law behavior of storage and loss moduli, G ' = G ~?0.5 , in the range of ? where the high- ? plateau was supposed to emerge. This lack of the high- ? plateau was attributed to retardation of the Rouse equilibration of the PI chain over the entanglement length due to the hindrance from the slow PtBS chains: The PI and PtBS chains were equilibrated cooperatively, and the retardation due to PtBS shortened the plateau for PI to a width not resolved experimentally. A simple model for this cooperative equilibration formulated on the basis of the dielectric data described the viscoelastic data surprisingly well.

  10. 40 CFR 721.10326 - 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ester, polymer with butyl 2-propenoate, ethyl 2-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2...-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2-propenoate (1:2), 2,2?-(1,2-diazenediyl)bis - and 2,2... butyl 2-propenoate, ethyl 2-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2-propenoate (1:2),...

  11. 40 CFR 721.10326 - 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ester, polymer with butyl 2-propenoate, ethyl 2-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2...-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2-propenoate (1:2), 2,2?-(1,2-diazenediyl)bis - and 2,2... butyl 2-propenoate, ethyl 2-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2-propenoate (1:2),...

  12. Electrochemical nucleophilic synthesis of di-tert-butyl-(4-[18F]fluoro-1,2-phenylene)-dicarbonate.

    PubMed

    He, Qinggang; Wang, Ying; Alfeazi, Ines; Sadeghi, Saman

    2014-09-01

    An electrochemical method with the ability to conduct (18)F-fluorination of aromatic molecules through direct nucleophilic fluorination of cationic intermediates is presented in this paper. The reaction was performed on a remote-controlled automatic platform. Nucleophilic electrochemical fluorination of tert-butyloxycarbonyl (Boc) protected catechol, an intermediate model molecule for the positron emission tomography (PET) probe (3,4-dihydroxy-6-[(18)F]fluoro-L-phenylalanine), was performed. Fluorination was achieved under potentiostatic anodic oxidation in acetonitrile containing Et3N·3HF and other supporting electrolytes. Radiofluorination efficiency was influenced by a number of variables, including the concentration of the precursor, concentration of Et3N·3HF, type of supporting electrolyte, temperature and time, as well as applied potentials. Radio-fluorination efficiency of 10.4±0.6% (n=4) and specific activity of up to 43GBq/mmol was obtained after 1h electrolysis of 0.1M of 4-tert-butyl-diboc-catechol in the acetonitrile solution of Et3N·3HF (0.033M) and NBu4PF6 (0.05M). Density functional theory (DFT) was employed to explain the tert-butyl functional group facilitation of electrochemical oxidation and subsequent fluorination. PMID:25000498

  13. Electrochemical nucleophilic synthesis of di-tert-butyl-(4-[18F]fluoro-1,2-phenylene)-dicarbonate

    PubMed Central

    He, Qinggang; Wang, Ying; Alfeazi, Ines; Sadeghi, Saman

    2015-01-01

    An electrochemical method with the ability to conduct 18F-fluorination of aromatic molecules through direct nucleophilic fluorination of cationic intermediates is presented in this paper. The reaction was performed on a remote-controlled automatic platform. Nucleophilic electrochemical fluorination of tert-butyloxycarbonyl (Boc) protected catechol, an intermediate model molecule for the positron emission tomography (PET) probe (3,4-dihydroxy-6-[18F]fluoro-l-phenylalanine), was performed. Fluorination was achieved under potentiostatic anodic oxidation in acetonitrile containing Et3N · 3HF and other supporting electrolytes. Radiofluorination efficiency was influenced by a number of variables, including the concentration of the precursor, concentration of Et3N · 3HF, type of supporting electrolyte, temperature and time, as well as applied potentials. Radiofluorination efficiency of 10.4 ± 0.6% (n = 4) and specific activity of up to 43 GBq/mmol was obtained after 1 h electrolysis of 0.1 M of 4-tert-butyl-diboc-catechol in the acetonitrile solution of Et3N · 3HF (0.033 M) and NBu4PF6 (0.05 M). Density functional theory (DFT) was employed to explain the tert-butyl functional group facilitation of electrochemical oxidation and subsequent fluorination. PMID:25000498

  14. Comparative efficiencies of isopropyl and tert-butyl alcohols for extracting zeins from maize endosperm.

    PubMed

    Landry, Jacques; Delhaye, Sonia; Damerval, Catherine

    2002-07-01

    Protein of endosperm of maize grains originating from three wild-type inbreds and their opaque-2 versions were solubilized in diverse extracts (E) by the sequential use of 0.5 M NaCl, water (E(1,2)), alcohol plus a reducing agent (E(3)), and salt plus a reducing agent (E(4)). Zeins were isolated in extracts E(3) and E(4) obtained by using 55% (w/w) isopropyl alcohol (i-PrOH) + 0.2% dithiothreitol (DTT) followed by 0.5 M NaCl + 0.2% DTT buffered at pH 10 or 60% tert-butyl alcohol (t-BuOH) + 0.2% DTT followed by 0.5% sodium acetate + 0.2% DTT in 30% t-BuOH. For a given genotype the percentage of extracted zeins was independent of the nature of the alcohol. The latter had a slight effect on the respective magnitude of E(3) and E(4): E(3) increased at the expense of E(4) when t-BuOH was substituted to i-PrOH for their isolation. The percentage of the total endosperm nitrogen present in E(3) + E(4) was identical to that of fractions F(II) + F(III) + F(IV) isolated according to the classical Landry-Moureaux extraction procedure. SDS-PAGE analysis revealed the presence of all types of zeins (alpha, beta, gamma, and delta) in E(3) and F(III), residual zeins in E(4) isolated with t-BuOH, and streaking only in E(4) and F(IV) isolated with NaCl at pH 10. The data together with those of the literature were discussed with regard to the influence of procedure on the yield of zeins using alcoholic extraction. PMID:12083896

  15. The Synthesis and Isolation of N-Tert-Butyl-2-Phenylsuccinamic Acid and N-Tert-Butyl-3-Phenylsuccinamic Acid: An Undergraduate Organic Chemistry Laboratory Experiment

    ERIC Educational Resources Information Center

    Cesare, Victor; Sadarangani, Ishwar; Rollins, Janet; Costello, Dennis

    2004-01-01

    The facile, high yielding synthesis of phenylsuccinamic acids is described and one of these syntheses, the reaction of phenylsuccinic anhydride with tert-butylamine, is successfully modified and adapted for use in the second-semester organic chemistry laboratory at St. John's University. Succinamic acids are compounds that contain both the amide…

  16. Structural characterization and electrochemical properties of the 3,3'-5,5'-tetra- tert-butyl-4,4'-diphenoquinone

    NASA Astrophysics Data System (ADS)

    Tümer, Mehmet; Aslanta?, Mehmet; ?ahin, Ertan; Deligönül, Nihal

    2008-08-01

    Crystals of the 3,3'-5,5'-tetra- tert-butyl-4,4'-diphenoquinone (TTBDQ) in the reaction mixture DCM/MeOH (1:1, v/v) were obtained as a result of C sbnd C coupling reaction of the sterically hindered phenol (2,6-di- tert-butylphenol, DTBP) using the binuclear Co(II) complexes. The oxidation product (TTBDQ), C 28H 40O 2, crystallizes in the space group P1¯ with one-half molecule in the asymmetric unit and the other half generated by an inversion centre. The diphenoquinone moiety is planar within ±0.016(3) Å. The crystal structure is stabilized by intramolecular C sbnd H⋯O hydrogen bonds. The spectroscopic and electrochemical properties of the TTBDQ also have been studied.

  17. Degradation in chlorinated water of the UV filter 4-tert-butyl-4'-methoxydibenzoylmethane present in commercial sunscreens.

    PubMed

    Crista, Diana M A; Miranda, Margarida S; Esteves da Silva, Joaquim C G

    2015-01-01

    4-tert-Butyl-4'-methoxydibenzoylmethane (BMDM) is a widely used ultraviolet A filter. In this work, we have studied the effect of chlorine and dissolved organic matter (DOM) concentrations on the stability of UV filter (BMDM) present in two commercial sunscreen cream formulations in water. An experimental design was used to assess the effect of the two experimental factors on the degradation of BMDM. Higher concentrations of chlorine lead to higher degradation percentages of BMDM and higher concentrations of DOM inhibit its degradation. Moreover, a mono and a dichloro derivate of BMDM were identified as by-products. PMID:25399819

  18. (E)-4-tert-Butyl-2-(2,6-diisopropyl-phenyl-imino-meth-yl)-6-(morpholinometh-yl)phenol.

    PubMed

    Zhu, Zhichen; Cui, Jin; Zhang, Mingjie

    2008-01-01

    In the mol-ecule of the title compound, C(28)H(40)N(2)O(2), the tert-butyl group is disordered over two positions; site-occupation factors were kept fixed at 0.5. The morpholine ring has a chair conformation. Intra-molecular O-H?N hydrogen bonding results in the formation of a planar six-membered ring, which is oriented at a dihedral angle of 0.70?(3)° with respect to the adjacent aromatic ring. The dihedral angle between the benzene rings is 67.66?(3)°. PMID:21202133

  19. (E)-4-tert-Butyl-2-(2,6-diisopropyl­phenyl­imino­meth­yl)-6-(morpholinometh­yl)phenol

    PubMed Central

    Zhu, Zhichen; Cui, Jin; Zhang, Mingjie

    2008-01-01

    In the mol­ecule of the title compound, C28H40N2O2, the tert-butyl group is disordered over two positions; site-occupation factors were kept fixed at 0.5. The morpholine ring has a chair conformation. Intra­molecular O—H?N hydrogen bonding results in the formation of a planar six-membered ring, which is oriented at a dihedral angle of 0.70?(3)° with respect to the adjacent aromatic ring. The dihedral angle between the benzene rings is 67.66?(3)°. PMID:21202133

  20. The importance of the hydroxyl moieties for inhibition of the Ca(2+)-ATPase by trilobolide and 2,5-di(tert-butyl)-1,4-benzohydroquinone.

    PubMed

    Wictome, M; Holub, M; East, J M; Lee, A G

    1994-03-15

    Trilobolide and 2,5-di(tert-butyl)-1,4-benzohydroquinone (BHQ) are potent inhibitors of the Ca(2+)-ATPase of skeletal muscle sarcoplasmic reticulum. Desoxytrilobolide and 2,5-di(tert-butyl)-1,4-diacetylphenol (acetyl-BHQ) have much lower potencies than their parent compounds and 2,5-di(tert-butyl)-1,4-benzoquinone (BQ) has no effect on ATPase activity. Studies using the ATPase labelled with 4-nitrobenzo-2-oxa-1,3-diazole (NBD) suggest that both trilobolide and BHQ bind more strongly to the E2 conformation of the ATPase than to the E1 conformation. Desoxytrilobolide, acetyl-BHQ and BQ have little effect on the E1/E2 equilibrium. Studies with mixtures of trilobolide and desoxytrilobolide suggest that the inactive derivatives are unable to bind to the ATPase. PMID:8135840

  1. Structural Properties of Tetra-tert-butyl Zinc(II) Phthalocyanine Isomers on a Au(111) Z. T. Deng, H. M. Guo, W. Guo, L. Gao, Z. H. Cheng, D. X. Shi, and H.-J. Gao*

    E-print Network

    Gao, Hongjun

    Structural Properties of Tetra-tert-butyl Zinc(II) Phthalocyanine Isomers on a Au(111) Surface Z. T-assembly behavior of the mixture of tetra-tert-butyl zinc(II) phthalocyanine (TB-ZnPc) isomers on a Au(111) surface are added to four peripheral benzene rings of zinc(II) phthalocyanine, which gives the planar molecules

  2. Magnetic properties of a new N-TEMPO-tert-butyl substituted salicylaldimines and their biradical palladium(II) complexes

    NASA Astrophysics Data System (ADS)

    Kasumov, Veli T.; Yerli, Yusuf; Topkaya, Ramazan

    2013-01-01

    A new TEMPO bearing tert-butylated salicylaldimines 1 and 2, as well as early reported 3, and their bis(N-TEMPO-tert-butylated salicylaldiminato)palladium(II) biradical complexes 4-6 have been synthesized and characterized by elemental analyses, IR, UV/vis, ESR and an SQUID magnetometer. The solid state g-factors (2.0116-2.0168) for 4-6 suggest the existence of the significant metal-orbital contribution to the SOMO of nitroxyl radicals. The ?mT vs. T plots for 1 and 2 indicate that the ?mT decreases as T is lowered from 300 to 20 K, suggesting the existence of weak antiferromagnetic interactions in these radicals. Variable-temperature dependence (10-300 K) magnetic susceptibility data for biradical complexes 4-6 revealed the existence of ferromagnetic and antiferromagnetic behavior around at 10-220 K range for 4. The 1/?m data for 1-6 follow the Curie-Weiss law with negative ? throughout the above temperature range.

  3. Photoinduced Reactivity of the Soft Hydrotris(6-tert-butyl-3-thiopyridazinyl)borate Scorpionate Ligand in Sodium, Potassium, and Thallium Salts.

    PubMed

    Tüchler, Michael; Belaj, Ferdinand; Raber, Georg; Neshchadin, Dmytro; Mösch-Zanetti, Nadia C

    2015-09-01

    The soft scorpionate ligand hydrotris(6-tert-butyl-3-thiopyridazinyl)borate (Tn) was found to exhibit pronounced photoreactivity. Full elucidation of this process revealed the formation of 6-tert-butylpyridazine-3-thione (PnH) and 4,5-dihydro-6-tert-butylpyridazine-3-thione (H2PnH). Under exclusion of light, no solvolytic reactions occur, allowing the development of high-yield preparation protocols for the sodium, potassium, and thallium salts and improving the yield for their derived copper boratrane complex. The photoreactivity is relevant for all future studies with electron-deficient scorpionate ligands. PMID:26260148

  4. Conformations and Barriers to Methyl Group Internal Rotation in Two Asymmetric Ethers: Propyl Methyl Ether and Butyl Methyl Ether

    NASA Astrophysics Data System (ADS)

    Long, B. E.; Dechirico, F.; Cooke, S. A.

    2012-06-01

    The conformational preferences of the O-C-C-C unit are important in many biological systems with the unit generally preferring a gauche configuration compared to an anti configuration. Butyl methyl ether and propyl methyl ether provide very simple systems for this phenomenom to manifest. Pure rotational spectra of the title molecules have been recorded using chirped pulse Fourier transform microwave spectroscopy (CP-FTMW). In the case of butyl methyl ether, only one conformer has been observed. This conformer has torsional angles of COCC = 180°, OCCC = 62° and CCCC = 180° (anti-gauche-anti) and rotational constants of A = 10259.4591(33) MHz, B = 1445.6470(13) MHz, and C = 1356.2944(14) MHz. The rotational spectrum was doubled and has been analyzed to produce an effective barrier to methyl group internal rotation of 780(35) cm-1. A prior rotational spectroscopic study on propyl methyl ether had focused only on the high energy anti-anti conformer. We have analyzed spectra from the lowest energy anti-gauche conformer and the spectroscopic constants will be presented. A summary of the differences in conformational energies and methyl group internal rotation barriers for the class of aliphatic asymmetric ethers will be presented. K. N. Houk, J. E. Eksterowicz, Y.-D. Wu, C. D. Fuglesang, D. B. Mitchell. J. Am. Chem. Soc. 115 (4170), 1993. Hiroshi Kato, Jun Nakagawa, Michiro Hayashi. J. Mol. Spectrosc. 80 (272), 1980.

  5. Sulfuric acid functional zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts for alkylation of phenol with tert-butyl alcohol

    NASA Astrophysics Data System (ADS)

    Jiang, Tingshun; Cheng, Jinlian; Liu, Wangping; Fu, Lie; Zhou, Xuping; Zhao, Qian; Yin, Hengbo

    2014-10-01

    Several zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts (SO42-/Zr-MCM-48 and SO42-/Al-MCM-48) were prepared by the impregnation method and their physicochemical properties were characterized by means of XRD, FT-IR, TEM, NH3-TPD and N2 physical adsorption. Also, the catalytic activities of these solid acid catalysts were evaluated by the alkylation of phenol with tert-butyl alcohol. The effect of weight hour space velocity (WHSV), reaction time and reaction temperature on catalytic properties was also studied. The results show that the SO42-/Zr-MCM-48 and SO42-/Al-MCM-48 still have good mesoporous structure and long range ordering. Compared with the Zr (or Al)-MCM-48 samples, SO42-/Zr-MCM-48 and SO42-/Al-MCM-48 solid acid catalysts have strong acidity and exhibit high activities in alkylation reaction of phenol with tert-butyl alcohol. The SO42-/Zr-MCM-48-25 (molar ratio of Si/Zr=0.04) catalyst was found to be the most promising and gave the highest phenol conversion among all catalysts. A maximum phenol conversion of 91.6% with 4-tert-butyl phenol (4-TBP) selectivity of 81.8% was achieved when the molar ratio of tert-butyl alcohol:phenol is 2:1, reaction time is 2 h, the WHSV is 2 h-1 and the reaction temperature is 140 °C.

  6. Vibrational spectroscopic investigations and computational study of 5-tert-butyl-N-(4-trifluoromethylphenyl)pyrazine-2-carboxamide.

    PubMed

    Joseph, Tomy; Varghese, Hema Tresa; Yohannan Panicker, C; Viswanathan, K; Dolezal, Martin; Manojkumar, T K; Van Alsenoy, Christian

    2013-09-01

    Pyrazine and its derivatives form an important class of compounds present in several natural flavors and complex organic molecules. Quantum chemical calculations of the equilibrium geometry, harmonic vibrational frequencies, infrared intensities and Raman activities of 5-tert-Butyl-N-(4-trifluoromethylphenyl)pyrazine-2-carboxamide in the ground state were carried out by using density functional methods. Potential energy distribution of normal modes of vibrations was done using GAR2PED program. Nonlinear optical behavior of the examined molecule was investigated by the determination of first hyperpolarizability. The calculated HOMO and LUMO energies show the chemical activity of the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The calculated geometrical parameters are in agreement with that of similar derivatives. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. PMID:23727674

  7. 2,4-Di-tert-butyl phenol as the antifungal, antioxidant bioactive purified from a newly isolated Lactococcus sp.

    PubMed

    Varsha, Kontham Kulangara; Devendra, Leena; Shilpa, Ganesan; Priya, Sulochana; Pandey, Ashok; Nampoothiri, Kesavan Madhavan

    2015-10-15

    The volatile organic compound 2,4-di-tert-butyl phenol (2,4 DTBP) was purified from the cell free supernatant of a newly isolated Lactococcus sp. by solvent extraction and chromatographic techniques. Molecular characterization of the compound by ESI-MS, (1)H NMR and FTIR analysis revealed the structure, C14H22O. Fungicidal activity was demonstrated against Aspergillus niger, Fusarium oxysporum and Penicillium chrysogenum by disc diffusion assay. Among the cell lines tested for cytotoxicity of this compound (normal cell line H9c2 and cancer cell lines HeLa and MCF-7), a remarkable cytotoxicity against HeLa cells with an IC50 value of 10 ?g/mL was shown. A biocontrol experiment with 2,4 DTBP supplemented fraction prevented growth of the abovementioned fungi on wheat grains. The study further strengthens the case for development of biopreservatives and dietary antioxidants from lactic acid bacteria for food applications. PMID:26164257

  8. [Contribution to the migration and toxicology of 2-(2'-hydroxy-3'-tert-butyl-5'-methylpheny)-5-chlorobenzotriazole].

    PubMed

    Uhde, W J; Horácek, J

    1977-01-01

    Studies on the use of an ultraviolet-absorbing agent based on hydroxybenzotriazole for commodities of low-pressure and high-pressure polyethylene and polypropylene show that the migration is only slight in aqueous and acidic foods and in foodstuffs with low alcohol content. Sunflower oil, n-heptane (as a fat-stimulating test solution) and 50% ethanol as test solutions yielded higher migration values. Gas chromatographic, polarographic and thin-layer chromatographic methods were used to determine the ultraviolet-absorbing agent. Concerns about a possible photosensitizing effect of 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole were experimentally tested and turned out to be unfounded. From the viewpoint of safety, there are no contraindications to the use of polyolefines in packing materials for most foods. As to fat-containing and strongly alcoholic foodstuffs, the authorization should be conditioned on the circumstances of use. PMID:927485

  9. Photochemical transformations. 30. Photosolvolysis of benzyl chlorides in tert-butyl alcohol. 2. Nature of excited states

    SciTech Connect

    Cristol, S.J.; Bindel, T.H.

    1981-12-02

    The photosolvolysis of a number of benzyl chlorides in tert-butyl alcohol, both as a result of direct irradiation and ketone triplet sensitization, has been studied. A variety of sensitization and quenching techniques have been used. The results obtained are rationalized by the assumption that there are two triplet states of the benzyl chlorides accessible in these experiments-one a short-lived upper state, which leads to solvolysis product, and another a long-lived (lower energy) state, which reverts to ground-state reactant. Consistent with this idea, m-methoxybenzyl chloride is shown to quench the photoreactions of benzophenone with benzhydrol without the formation of a significant amount of reactive species. The effects of wavelength on the reactions of p-acetobenzyl chloride are measured and discussed in terms of the two-triplet concept.

  10. Percutaneous absorption of 2,6-di-tert-butyl-4-nitrophenol (DBNP) in isolated perfused porcine skin.

    PubMed

    Inman, Alfred O; Still, Kenneth R; Jederberg, Warren W; Carpenter, Robert L; Riviere, Jim E; Brooks, James D; Monteiro-Riviere, Nancy A

    2003-06-01

    DBNP (2,6-di-tert-butyl-4-nitrophenol) has been reported as a potential contaminant in submarines. This yellow substance forms when lubrication oil mist containing the antioxidant additive 2,6-di-tert-butylphenol passes through an electrostatic precipitator and is nitrated. Percutaneous absorption of 14C-DBNP was assessed in the isolated perfused porcine skin flap (IPPSF). Four treatments were studied (n=4 flaps/treatment): 40.0 microgram/cm(2) in 100% ethanol; 40.0 microgram/cm(2) in 85% ethanol/15% H(2)O; 4.0 microgram/cm(2) in 100% ethanol; and 4.0 microgram/cm(2) in 85% ethanol/15% water. DBNP absorption was minimal across all treatment groups, with the highest absorption detected being only 1.08% applied dose in an aqueous ethanol group. The highest mass of 14C-DBNP absorbed was only 0.5 microgram. The majority of the applied dose remained on the surface of the skin. This suggests that there is minimal dermal exposure of DBNP when exposed topically to skin. PMID:12781207

  11. Two-year drinking water carcinogenicity study of methyl tertiary-butyl ether (MTBE) in Wistar rats.

    PubMed

    Dodd, Darol; Willson, Gabrielle; Parkinson, Horace; Bermudez, Edilberto

    2013-07-01

    Methyl tertiary-butyl ether (MTBE) has been used as a gasoline additive to reduce tailpipe emissions and its use has been discontinued. There remains a concern that drinking water sources have been contaminated with MTBE. A two-year drinking water carcinogenicity study of MTBE was conducted in Wistar rats (males, 0, 0.5, 3, 7.5 mg ml(-1); and females, 0, 0.5, 3, and 15 mg ml(-1)). Body weights were unaffected and water consumption was reduced in MTBE-exposed males and females. Wet weights of male kidneys were increased at the end of two years of exposure to 7.5 mg ml(-1) MTBE. Chronic progressive nephropathy was observed in males and females, was more severe in males, and was exacerbated in the high MTBE exposure groups. Brain was the only tissue with a statistically significant finding of neoplasms. One astrocytoma (1/50) was found in a female rat (15 mg ml(-1)). The incidence of brain astrocytomas in male rats was 1/50, 1/50, 1/50 and 4/50 for the 0, 0.5, 3 and 7.5 mg ml(-1) exposure groups, respectively. This was a marginally significant statistical trend, but not statistically significant when pairwise comparisons were made or when multiple comparisons were taken into account. The incidence of astrocytoma fell within historical control ranges for Wistar rats, and the brain has not been identified as a target organ following chronic administration of MTBE, ethyl tert-butyl ether, or tertiary butyl alcohol (in drinking water) to mice and rats. We conclude that the astrocytomas observed in this study are not associated with exposure to MTBE. PMID:22161475

  12. (2-tert-Butyl-3-phenyl-2,3-di­hydro­isoxazole-4,5-di­yl)bis­(phenyl­methanone)

    PubMed Central

    Sandhya, R.; Sithambaresan, M.; Prathapan, S.; Kurup, M. R. Prathapachandra

    2013-01-01

    The phenyl and tert-butyl groups of the title compound, C27H25NO3, exhibit a trans configuration in agreement with the stereochemistry of the Z phenyl-N-tert-butyl­nitrone starting material. The attached carbonyl groups are not coplanar with the neighboring di­hydro­isoxazole ring and the phenyl rings they are bonded to, with torsion angles of 59.26?(8), 17.53?(11), 16.52?(12) and 52.86?(7)°. The dihedral angle between the di­hydro­isoxazole ring and the directly attached phenyl group is 86.86?(8)°. There are two nonclassical inter­molecular C—H?O hydrogen-bonding inter­actions that operate together with an inter­molecular C—H?? inter­action to form a supramolecular architecture in the crystal system. PMID:24109366

  13. Optimized synthesis of a tert-butyl-phenyl-substituted tetrapyridophenazine ligand and its Ru(II) complexes and determination of dimerization behaviour of the complexes through supramolecular "Fingerhakel".

    PubMed

    Ritter, K; Pehlken, C; Sorsche, D; Rau, S

    2015-05-21

    The synthesis of tpphz(tbp)2 (tpphz(tbp)2 = 3,16-di(tert-butyl-phenyl)-tetrapyrido[3,2-a:2?,3?-c:3??,2??-h:2???,3???-j]phenazine) has been optimized by using a new synthetic route. The complexes Ru(tbp)2tpphz, Rutpphz(tbp)2, Rutpphz(tbp)2Ru and the reference compound Ru(tbp)2phen (where Ru = (tbbpy)2Ru, tbbpy = 4,4?-di-tert-butyl-2,2?-bipyridine and (tbp)2phen = 3,8-bis(4-tert-butyl-phenyl)-1,10-phenanthroline) have been synthesized and characterized. Crystal structures or structural motifs could be obtained for each intermediate and complex and for the first time a tpphz based uncomplexed ligand could be investigated in the solid state. The mononuclear complexes Ru(tbp)2tpphz and Rutpphz(tbp)2 form ?–? stacked dimers in the solid state. The latter exhibits an interesting aggregation in the solid state with three ?-interactions. Concentration dependent aggregation of these isomers in solution is observed with the aid of 1H-NMR investigations. Out of those dimerization constants (KD) could be calculated for the complexes Ru(tbp)2tpphz and Rutpphz(tbp)2. The values differ significantly. Photophysical and electrochemical properties of the presented complexes were investigated and compared with reference compounds. The tert-butyl-phenyl-substitution induces a stabilization of the 1MLCT and 3MLCT states localized on the phenanthroline part of the bridging ligand. The 3MLCT localized on the phenazine portion seems to be not or only to a minor extent influenced by these substituents. PMID:25871461

  14. Syntheses, properties, and reactions of transition metal complexes of di(tert-butyl)amide and 2,2,6,6-tetramethylpiperidide

    NASA Astrophysics Data System (ADS)

    Davis, Luke M.

    Nitrides of the transition metals of groups 7-11 possess desirable properties, such as higher hardness and saturation magnetization than the corresponding metals. These nitrides have realized and potential applications in tool coatings and magnetic recording media. In order to develop new chemical vapor deposition (CVD) precursors for these late transition metal nitrides, we have explored the synthesis, characterization, and CVD of late transition metal complexes of the sterically demanding ligands di(tert-butyl)amide and 2,2,6,6-tetramethylpiperidide. Treatment of MnBr2(thf)2, FeBr2(dme), CoBr2(dme), and NiBr2(dme) with two equivalents of LiN(t-Bu)2 in pentane, followed by sublimation in static vacuum, affords the two-coordinate compounds M[N(t-Bu)2]2 (M = Mn, Fe, Co, Ni) previously reported by our group. Previous work established that the Mn and Fe compounds have linear N-M-N angles, whereas the Co and Ni compounds are bent. In addition, the Fe and Co compounds have large orbital contributions to their magnetic moments, whereas the Mn and Ni compounds do not. In order to understand these properties, the electronic structures of the M[N(t-Bu)2]2 compounds have been described using the Angular Overlap Model (AOM). Two conclusions help rationalize the previously observed molecular properties of these and other two-coordinate compounds: (1) The potential energy surfaces for two-coordinate compounds are nearly flat, varying only a few kcal/mol even with 30° changes in the N-M-N angle, and (2) the ground state configurations for two-coordinate d2 and d3 (and therefore also d7 and d8) compounds experience strong inter-electron repulsion and extensive state mixing. Low-temperature CVD from the reaction between these two-coordinate M[N(t-Bu)2]2 compounds and ammonia affords manganese, iron, cobalt, and nickel nitride thin films. Deposition rates as high as 18 nm/min are observed for cobalt nitride, and deposition temperatures as low as 25 °C are observed for iron nitride. The XPS binding energies confirm that the nitrogen is present as nitride in all cases. The M:N ratio in the deposited films decreases from Mn (2.5) to Fe (4) to Co (4.6-6) to Ni (9). Carbon contamination in the films is minimal for the manganese, iron, and cobalt nitride films, but similar to the nitrogen content in the nickel nitride films. Comparing the growth onset temperatures with the decomposition temperatures of the compounds M(NH2)2 supports the intermediacy in the film growth of the latter species, which are the expected products of the transamination of M[N(t-Bu)2]2 compounds with NH3. Treatment of MnBr2(thf)2, FeBr2(dme), and CoBr2(dme) with two equivalents of lithium 2,2,6,6-tetramethylpiperidide, Li(tmp), in pentane, followed by sublimation in static vacuum, affords the new compounds M(tmp)2 (M = Mn, Fe, Co). The heteroleptic, dinuclear three-coordinate compounds Fe2(tmp)3(OEt) and [Li(dme)][CoBr(tmp)2] have also been isolated. Crystallographic studies of Fe(tmp)2 demonstrate that the tmp ligand, which is the cyclic analogue of di(tert-butyl)amide with a slightly compressed C-N-C angle, can also enforce two-coordination. The Fe-N bonds are similar to those in the linear compound Fe[N(t-Bu)2]2, although the N-Fe-N angle of 173° and ligand dihedral angle of 73° are smaller. Fe(tmp)2 might therefore be expected to have a less degenerate ground state. Treatment of TiCl4 with two equivalents of H(tmp) affords the new compound Ti2Cl6(tmp)2. In contrast, treatment of TiCl4 or TiCl4(thf)2 with three equivalents of Li(tmp) induces ring-opening dealkylation of one tmp ligand and formation of a 1,1,5-trimethyl-5-hexenylimido ligand. A similar reaction is known for the di(tert-butyl)amido ligand.We conclude that the synthesis of early transition metal tmp and di(tert-butyl)amide compounds is hampered by the high electropositivity of these metals, which activates the methyl protons towards gamma-deprotonation. (Abstract shortened by UMI.).

  15. Enhanced diisobutene production in the presence of methyl tertiary butyl ether

    DOEpatents

    Smith, L.A. Jr.

    1983-03-01

    In the liquid phase reaction of isobutene in the presence of resin cation exchange resins with itself in a C[sub 4] hydrocarbon stream to form dimers, the formation of higher polymers, oligomers, and co-dimer by-products is suppressed by the presence of 0.0001 to 1 mole per mole of isobutene of methyl tertiary butyl ether. 1 fig.

  16. REFINED PBPK MODEL OF AGGREGATE EXPOSURE TO METHYL TERTIARY-BUTYL ETHER

    EPA Science Inventory

    Aggregate (multiple pathway) exposures to methyl tertiary-butyl ether (MTBE) in air and water occur via dermal, inhalation, and oral routes. Previously, physiologically-based pharmacokinetic (PBPK) models have been used to quantify the kinetic behavior of MTBE and its primary met...

  17. Enhanced diisobutene production in the presence of methyl tertiary butyl ether

    DOEpatents

    Smith, Jr., Lawrence A. (Bellaire, TX)

    1983-01-01

    In the liquid phase reaction of isobutene in the presence of resin cation exchange resins with itself in a C.sub.4 hydrocarbon stream to form dimers, the formation of higher polymers, oligomers, and co-dimer by-products is suppressed by the presence of 0.0001 to 1 mole per mole of isobutene of methyl tertiary butyl ether.

  18. PHYSIOLOGICALLY BASED PHARMACOKINETIC MODEL FOR HUMAN EXPOSURES TO METHYL TERTIARY-BUTYL ETHER

    EPA Science Inventory

    Humans can be exposed by inhalation, ingestion, or dermal absorption to methyl tertiary-butyl ether (MTBE), an oxygenated fuel additive, from contaminated water sources. The purpose of this research was to develop a physiologically based pharmacokinetic model describing in human...

  19. Solution processable 2-(trityloxy)ethyl and tert-butyl group containing amorphous molecular glasses of pyranylidene derivatives with light-emitting and amplified spontaneous emission properties

    NASA Astrophysics Data System (ADS)

    Zarins, Elmars; Vembris, Aivars; Misina, Elina; Narels, Martins; Grzibovskis, Raitis; Kokars, Valdis

    2015-11-01

    Small organic molecules with incorporated 4H-pyran-4-ylidene (pyranylidene) fragment as the ?-conjugation system which bonds the electron acceptor fragment (A) with electron donor part (D) in the molecule - also well known as derivatives of 4-(dicyano-methylene)-2-methyl-6-[p-(dimethylamino)styryl]-4H-pyran (DCM) laser dye-have attracted considerable attention of scientists as potential new generation materials for organic photonics and molecular electronics due to their low-cost fabrication possibility, flexibility and low-weight. Six glassy derivatives of 4H-pyran-4-ylidene (pyranylidene) with attached bulky 2-(trityloxy)ethyl and tert-butyl groups are described in this report. Almost all of the synthesized compounds form good optical quality transparent amorphous films from volatile organic solvents and could be obtained in good yields up to 75%. Their light emission in solution and thin solid films is in the range of 600-700 nm, they are thermally stable and show glass transition in the range of 108-158 °C. The amplified spontaneous emission threshold values of the neat films of the glassy pyranylidene derivatives vary from 155 to 450 ?J/cm2 and their HOMO and LUMO energy levels are between of those of tris(8-hydroxy quinolinato) aluminum (Alq3). The photoluminescence quantum yields of the glassy compounds are in the range from 1% to about 7.7% and their electroluminescence properties have been investigated. Therefore, glassy pyranylidene derivatives could be a very potential low-cost solution processable materials for Alq3 hosted light-amplification and light-emitting application studies.

  20. Structural, energetic, and UV-Vis spectral analysis of UVA filter 4-tert-butyl-4'-methoxydibenzoylmethane.

    PubMed

    Pinto da Silva, Luís; Ferreira, Paulo J O; Duarte, Darío J R; Miranda, Margarida S; Esteves da Silva, Joaquim C G

    2014-02-27

    The growing awareness of the harmful effects of ultraviolet (UV) solar radiation has increased the production and consumption of sunscreen products, which contain organic and inorganic molecules named UV filters that absorb, reflect, or scatter UV radiation, thus minimizing negative human health effects. 4-tert-Butyl-4'-methoxydibenzoylmethane (BMDBM) is one of the few organic UVA filters and the most commonly used. BMDBM exists in sunscreens in the enol form which absorbs strongly in the UVA range. However, under sunlight irradiation tautomerization occurs to the keto form, resulting in the loss of UV protection. In this study we have performed quantum chemical calculations to study the excited-state molecular structure and excitation spectra of the enol and keto tautomers of BMDBM. This knowledge is of the utmost importance as the starting point for studies aiming at the understanding of its activity when applied on human skin and also its fate once released into the aquatic environment. The efficiency of excitation transitions was rationalized based on the concept of molecular orbital superposition. The loss of UV protection was attributed to the enol ? keto phototautomerism and subsequent photodegradation. Although this process is not energetically favorable in the singlet bright state, photodegradation is possible because of intersystem crossing to the first two triplet states. PMID:24494821

  1. Conformational stability, vibrational and NMR analysis, chemical potential and thermodynamical parameter of 3-tert-butyl-4-hydroxyanisole.

    PubMed

    Balachandran, V; Karpagam, V; Revathi, B; Kavimani, M; Santhi, G

    2015-01-25

    The FT-IR and FT-Raman spectra of 3-tert-butyl-4-hydroxyanisole (TBHA) molecule have been recorded in the region 4000-400 cm(-1) and 3500-100 cm(-1), respectively. Optimized geometrical structure, harmonic vibrational frequencies has been computed by B3LYP level using 6-31G (d,p) and 6-311+G (d,p) basis sets. The observed FT-IR and FT-Raman vibrational frequencies are analyzed and compared with theoretically predicted vibrational frequencies. The geometries and normal modes of vibration obtained from DFT method are in good agreement with the experimental data. The Mulliken charges, the natural bonding orbital (NBO) analysis, the first-order hyperpolarizability of the investigated molecule were computed using DFT calculations. Besides, charge transfer occurring in the molecule between HOMO and LUMO energies, frontier energy gap, molecular electrostatic potential (MEP) were calculated and analyzed. The isotropic chemical shift computed by (1)H and (13)C nuclear magnetic resonance (NMR) chemical shifts of the TBHA calculated using the gauge invariant atomic orbital (GIAO) method also shows good agreement with experimental observations. PMID:25173520

  2. tert-Butyl hydroperoxide, an organic peroxide, causes temporary delay in hair growth in a neonatal rat model

    PubMed Central

    Wikramanayake, T. C.; Simon, J.; Mauro, L. M.; Perez, C. I.; Roberts, B.; Elgart, G.; Alvarez-Connelly, E.; Schachner, L. A.; Jimenez, J. J.

    2011-01-01

    Summary tert-Butyl hydroperoxide (tBHP), an organic peroxide, has been shown to cause irreversible damage to keratinocytes in vitro with prolonged administration at high concentrations, and reversible damage with short-term administration at low concentrations. To investigate the effects of tBHP on keratinocytes in vivo, we analysed hair growth in tBHP-treated neonatal rats. Sprague–Dawley and Long–Evans rat pups were injected subcutaneously with tBHP or vehicle once daily for 6 days, and hair growth was monitored. The tBHP-treated rats had a significant delay in hair growth. However, this delay reversed within days, and the hair coats, including hair pigmentation, of tBHP-treated and sham-treated rats were indistinguishable 2 weeks later. Histological analysis and BrdU labelling of S phase cells confirmed the delay in hair-follicle growth and its reversal in tBHP-treated rats. Our results indicated that the changes incurred in hair follicles by short-term use of high-dose oxidants in vivo are temporary and reversible. PMID:21418283

  3. tert-butyl hydroperoxide, an organic peroxide, causes temporary delay in hair growth in a neonatal rat model.

    PubMed

    Wikramanayake, T C; Simon, J; Mauro, L M; Perez, C I; Roberts, B; Elgart, G; Alvarez-Connelly, E; Schachner, L A; Jimenez, J J

    2011-08-01

    tert-butyl hydroperoxide (tBHP), an organic peroxide, has been shown to cause irreversible damage to keratinocytes in vitro with prolonged administration at high concentrations, and reversible damage with short-term administration at low concentrations. To investigate the effects of tBHP on keratinocytes in vivo, we analysed hair growth in tBHP-treated neonatal rats. Sprague-Dawley and Long-Evans rat pups were injected subcutaneously with tBHP or vehicle once daily for 6?days, and hair growth was monitored. The tBHP-treated rats had a significant delay in hair growth. However, this delay reversed within days, and the hair coats, including hair pigmentation, of tBHP-treated and sham-treated rats were indistinguishable 2?weeks later. Histological analysis and BrdU labelling of S phase cells confirmed the delay in hair-follicle growth and its reversal in tBHP-treated rats. Our results indicated that the changes incurred in hair follicles by short-term use of high-dose oxidants in vivo are temporary and reversible. PMID:21418283

  4. Thermodynamic and kinetic studies of the liquid phase synthesis of tert-butyl ethyl ether using a reaction calorimeter

    SciTech Connect

    Sola, L.; Pericas, M.A.; Cunill, F.; Tejero, J.

    1995-11-01

    The liquid-phase addition of ethanol to isobutene to give tert-butyl ethyl ether (ETBE) on the ion-exchange resin Lewatit K2631 has been studied in a calorimetric reactor. The heat capacity of ETBE and the enthalpy change of the ETBE synthesis reaction in the temperature range 312--333 K have been determined. ETBE heat capacity in the liquid phase has been found to follow the equation C{sub p} = 486.73 {minus} 2.253 (T/K) + 0.00479 (T/K){sup 2}. At 298 K the standard molar reaction enthalpy is {Delta}H{degree} = {minus}32.0 kJ/mol. A determination of the apparent activation energy of 86.5--89.2 kJ/mol has been performed graphically from the plots of heat flow rate versus time. An Eley-Rideal mechanism, with two active sites involved in the rate determining step, has been proved to be correct. From this model an apparent activation energy of 80.6 kJ/mol is deduced. A {minus}3.0 kJ/mol value has been found for the adsorption enthalpy of ethanol. This allows the estimation of the actual gel-phase activation energy of 77.6 kJ/mol.

  5. Synthesis and characterization of perfluoro-tert-butyl semifluorinated amphiphilic polymers and their potential application in hydrophobic drug delivery

    PubMed Central

    Decato, Sarah; Bemis, Troy; Madsen, Eric; Mecozzi, Sandro

    2014-01-01

    Semifluorinated polymer surfactants, composed of a monomethyl poly(ethylene glycol) (mPEG) hydrophilic head group and either 1, 2, or 3 perfluoro-tert-butyl (PFtB) groups as the fluorophilic tail, were synthesized, and their aqueous self-assemblies were investigated as a potential design for theranostic nanoparticles. Polymers with three PFtB groups (PFtBTRI) solely formed stable, spherical micelles, approximately 12 nm in size. These PFtBTRI surfactants demonstrate similar characteristics with those of polymers with linear perfluorocarbon tails, despite large differences in tail structure. For example, PFtB polymer solutions stably emulsified 20 v/v% sevoflurane with perfluorooctyl bromide (PFOB) as a stabilizer. However, these PFtB polymers have the additional potential to serve as F-MRI contrast agents. PFtBTRI micelles gave one narrow 19F-NMR signal in D2O, with T1 and T2 parameters of approximately 500 and 100 ms, respectively. 19F-MR images of PFtB polymer solutions at 1 mM gave intense signal at 4.7 T without sensitizers or selective excitation sequences. These preliminary data demonstrate the potential of PFtB polymers as a basic design, which can be further modified to serve as dual drug-delivery and imaging vehicles. PMID:25383100

  6. Novel tert-butyl migration in copper-mediated phenol ortho-oxygenation implicates a mechanism involving conversion of a 6-hydroperoxy-2,4-cyclohexadienone directly to an o-quinone

    PubMed

    Mandal; Macikenas; Protasiewicz; Sayre

    2000-08-11

    Copper mediated ortho-oxygenation of phenolates may proceed through the generation of a 6-peroxy-2,4-cyclohexadienone intermediate. To test this theory, we studied the fate of sodium 4-carbethoxy-2, 6-di-tert-butylphenolate, where the ortho-oxygenation sites are blocked by tert-butyl groups. Using the Cu(I) complex of N, N-bis(2-(N-methylbenzimidazol-2-yl)ethyl)benzylamine, isolation of the major oxygenated product and characterization by single-crystal X-ray crystallography and NMR spectroscopy revealed it to be 4-carbethoxy-3,6-di-tert-butyl-1,2-benzoquinone, resulting from a 1, 2-migration of a tert-butyl group. The independently prepared 6-hydroperoxide is transformed by the Cu(I)- (or Cu(II)-) ligand complex to the same o-quinone. The observed 1,2-migration of the tert-butyl group appears to reflect an electron demand created by rearrangement of the postulated peroxy intermediate. A mechanism proceeding alternatively through a catechol and subsequent oxidation to the o-quinone seems ruled out by a control study demonstrating that the requisite intermediate to catechol formation would instead eliminate the 2-tert-butyl group. PMID:10956455

  7. A COMPARISON OF LIQUID AND GAS-PHASE PHOTOOXIDATION TREATMENT OF METHYL TERTIARY BUTYL ETHER: SYNTHETIC AND FIELD SAMPLES

    EPA Science Inventory

    The feasibility of photo-oxidation treatment of metyl tert-butyl either (MTBE) in water was investigated using two systems, 1) a slurry falling film photo-reactor, and 2) an integrated air-stripping with gas phase photooxidation system. MTBE-contaminated synthetic water and field...

  8. Butylate

    Integrated Risk Information System (IRIS)

    Butylate ; CASRN 2008 - 41 - 5 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effects

  9. ``Living polymers'' in organic solvents : stress relaxation in bicopper tetracarboxylate/tert-butyl cyclohexane solutions

    NASA Astrophysics Data System (ADS)

    Terech, P.; Maldivi, P.; Dammer, C.

    1994-10-01

    Viscoelastic solutions of a bicopper tetracarboxylate complex in tert-butylcyclohexane have been studied by dynamic rheology in a wide range of concentrations (0.5-1.5 % volume fraction). The zero shear viscosity, the elastic modulus, the terminal stress relaxation time and the height of the high-frequency dip, in a Cole-Cole representation of the complex elastic modulus, follow scaling laws. The related exponents are discussed in the context of the physics of “living polymers” : a term used to describe worm-like species undergoing scission/recombination reactions competing mainly with the reptation motions of the chains. The current system, made up of molecular threads (17.5 Å diameter) of Cu2(O2C-CH(C2H5)C4H9)4 in the apolar solvent, is representative of a “living polymer” where, instead of mechanisms involving transient star polymeric crosslinks, a reversible scission mechanism prevails. The dynamics in the high-frequency range evolves from a regime where reptation is the dominant relaxation mechanism to a cross-over regime where “breathing” fluctuations and Rouse motions become important. Large modifications of the stress relaxation function occur for more concentrated systems. The binary system is the first example of a “living polymer” in an organic solvent and exhibits elastic moduli (G ? ca. 120 Pa à ? = 1 %) which are at least 20 times larger than those found for the aqueous “living polymer” systems. Les solutions viscoélastiques d'un tétracarboxylate binucléaire de cuivre dans le tert-butylcyclohexane sont étudiées par rhéologie en mode dynamique dans une gamme étendue de concentrations (0,5 %-15,5 %). La viscosité à gradient nul, le module élastique, le temps terminal de relaxation et la hauteur du puits à haute fréquence, dans une représentation Cole-Cole du module élastique complexe, suivent des lois d'échelles. Les exposants correspondants sont discutés dans le contexte de la physique des “polymères vivants" : un terme utilisé pour décrire des espèces vermiformes subissant des réactions de scission/recombinaison en compétition principalement avec les mouvements de reptation des chaînes. Le système constitué de fils moléculaires (17,5 Å de diamètre) de Cu2(O2C-CH(C2H5)C4H9)4 dans le solvant apolaire est typique de “polymères vivants” où le mécanisme de scission réversible prévaut plutôt que les mécanismes impliquant des nœuds transitoires branchés. La dynamique dans le domaine des hautes fréquences évolue d'un régime où la reptation est le mécanisme de relaxation dominant vers un régime intermédiaire où les modes de “respiration” et de Rouse deviennent importants. D'importantes modifications de la relaxation de contrainte se produisent pour les systèmes concentrés. Le système binaire est le premier exemple de “polymère vivant” en milieu organique et présente des modules élastiques (G ? ca. 120 Pa à ? = 1 %) qui sont au moins 20 fois plus grands que ceux des homologues aqueux.

  10. Biological stability of polyurethane modified with covalent attachment of di-tert-butyl-phenol.

    PubMed

    Stachelek, Stanley J; Alferiev, Ivan; Fulmer, James; Ischiropoulos, Harry; Levy, Robert J

    2007-09-15

    Polyurethane cardiovascular implants are subject to oxidation initiated surface degradation, which is mediated by monocyte-derived macrophages (MDM); this often leads to surface cracking and device failure. The present studies examined the hypothesis that covalently attaching antioxidant, di-tert-butylphenol (DBP), to the urethane nitrogens of a polyether polyurethane (PU) via bromo-alkylation reactions could prevent this problem. PU was configured with two dosages of DBP, 0.14 mM DBP/g PU of DBP (PU-DBP) and a more highly modified (HM) 0.40 mM DBP/g PU (PU-DBP-HM). THP-1 cells, a human MDM cell line, stimulated with phorbol ester and seeded on PU, PU-DBP, and PU-DBP-HM films were assessed for reactive oxygen species (ROS) production via a fluorescent based dihydrorhodamine-123 assay. Results from these studies showed a significant dose-dependent reduction of ROS levels for THP-1 cells seeded on PU-DBP versus unmodified PU. PU, PU-DBP, or PU-DBP-HM films were implanted into subdermal pouches of Sprague-Dawley rats. Films were explanted after 10 weeks and assessed for oxidative degradation via light and scanning electron microscopy (SEM) and Fourier transformation infrared spectroscopy (FTIR). Light microscopy showed extensive surface cracking, which was confirmed via SEM, on unmodified PU surfaces that was absent in both PU-DBP and PU-DBP-HM explanted films. FTIR analysis showed reduction in oxidation-induced ether crosslinking that was directly related to DBP dosages. It is concluded that modifying PU with the covalent attachment of an antioxidant confers biodegradation resistance in vivo in a dose dependent manner; this effect is likely due to quenching of the ROS generated by the adherent macrophages. PMID:17370325

  11. Isolation of phlorotannins from Eisenia bicyclis and their hepatoprotective effect against oxidative stress induced by tert-butyl hyperoxide.

    PubMed

    Kim, Sang Min; Kang, Kyungsu; Jeon, Je-Seung; Jho, Eun Hye; Kim, Chul Young; Nho, Chu Won; Um, Byung-Hun

    2011-11-01

    Eisenia bicyclis (Kjellman) Setchell is a common brown alga that inhabits the middle Pacific coast around Korea and Japan. In this study, the ethanol extract and its serial solvent fractions were prepared from fresh E. bicyclis, and their hepatoprotective effects were investigated against hepatotoxicity in tert-butyl hyperoxide(t-BHP)-injured HepG2 cells. When these samples were used at a dose of 10-40 ?g/mL?¹, they significantly protected the t-BHP-induced cell death in HepG2 cells. Among fractions, ethyl acetate fraction (EF) and n-butanol extract (BF) exhibited potent hepatoprotective activities (62.60% for EF and 64.86% for BF) in t-BHP-injured HepG2 cells at a concentration of 10 ?g/mL?¹. To find the potential factors for this activity, the samples were characterized on total phenolics, chlorophylls, carotenoids, and radical scavenging activity. Among them, EF showed the highest content of total phenolics and the strongest antioxidant activity both in on- and offline assays. Five phlorotannin compounds, oligomers of phloroglucinol, were isolated chromatographically from this fraction and structurally identified by (1)H-NMR and liquid chromatography-electrospray ionization-mass spectrometry analyses as eckol(1), 6,6'-bieckol(2), 8,8'-bieckol(3), dieckol(4), and phlorofucofuroeckol A(5). Compound 5 among five purified compounds showed the strongest protective activity (45.54%) at a concentration of 10 ?M. At the high dose (40 ?M), the protective activities of three compounds (compound 2, 4, and 5) were higher than that of quercetin treated with 10 ?M concentration. Therefore, we can speculate that they can be developed as potential candidates for natural hepatoprotective agents. PMID:21892616

  12. Technical note: quantification of zeins from corn, high-moisture corn, and corn silage using a turbidimetric method: comparative efficiencies of isopropyl and tert-butyl alcohols.

    PubMed

    Giuberti, G; Gallo, A; Masoero, F

    2012-06-01

    Zeins are corn endosperm storage proteins that encapsulate starch granules into a protein matrix, which can act as a barrier to starch accessibility and digestion. Laboratory methods to quantify zein are seldom used because they are considered arduous and time-consuming. A recently published rapid turbidimetric method (mTM) was reinvestigated by changing the solution originally used for the zein solubilization step. In particular, the aim was to explore whether, and to what extent, the use of tert-butyl alcohol (t-BuOH-mTM) in lieu of isopropyl alcohol (i-PrOH-mTM) was able to improve the quantification of zeins from dry corn, high-moisture corn, and corn silage samples. The nature of the alcohol influenced the zein extraction values, and t-BuOH-mTM gave higher zein values in corn (3.6 vs. 3.3 g/100 g of dry matter) and corn silage samples (1.2 vs. 0.9 g/100 g of dry matter) compared with i-PrOH-mTM. In contrast, similar zein extraction values were obtained for high-moisture corn (2.1 vs. 1.9 g/100 g of dry matter, respectively). Sodium dodecyl sulfate-PAGE analysis revealed no contamination by nonzein proteins with the use of tert-butyl alcohol. Overall, these findings indicated that tert-butyl alcohol has a greater ability to solubilize zein compared with isopropyl alcohol and thus the t-BuOH-mTM allowed greater extraction of zeins. Considering the growing interest of animal nutritionists in zein proteins, such results should provide useful information for routine laboratory analysis. PMID:22612972

  13. Multiple intramolecular hydrogen bonds in 2,4-di-tert-butyl-6-[N-(2,6-diisopropylphenyl)-P,P-diphenylphosphorimidoyl]phenol.

    PubMed

    Lee, Jong Dae; Suh, Il Hwan; Kang, Sang Ook

    2011-05-01

    The title compound, C(38)H(48)NOP, isolated from the reaction of (2-diphenylphosphanyl-4,6-di-tert-butyl)phenol with 2,6-diisopropylphenyl azide at 273 K, can act as an N,O-bidentate ligand. Crystal structure analysis shows a deviation from ideal tetrahedral symmetry around the P atom. The molecule exists as a monomer in the solid state, whose conformation is stabilized via multiple intramolecular hydrogen bonds. Geometric parameters from both experimental and theoretical calculations are compared. PMID:21540538

  14. Protective Effects of Rooibos (Aspalathus linearis) and/or Red Palm Oil (Elaeis guineensis) Supplementation on tert-Butyl Hydroperoxide-Induced Oxidative Hepatotoxicity in Wistar Rats.

    PubMed

    Ajuwon, Olawale R; Katengua-Thamahane, Emma; Van Rooyen, Jacques; Oguntibeju, Oluwafemi O; Marnewick, Jeanine L

    2013-01-01

    The possible protective effects of an aqueous rooibos extract (Aspalathus linearis), red palm oil (RPO) (Elaeis guineensis), or their combination on tert-butyl-hydroperoxide-(t-BHP-)induced oxidative hepatotoxicity in Wistar rats were investigated. tert-butyl hydroperoxide caused a significant (P < 0.05) elevation in conjugated dienes (CD) and malondialdehyde (MDA) levels, significantly (P < 0.05) decreased reduced glutathione (GSH) and GSH?:?GSSG ratio, and induced varying changes in activities of catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase in the blood and liver. This apparent oxidative injury was associated with histopathological changes in liver architecture and elevated levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH). Supplementation with rooibos, RPO, or their combination significantly (P < 0.05) decreased CD and MDA levels in the liver and reduced serum level of ALT, AST, and LDH. Likewise, changes observed in the activities of antioxidant enzymes and impairment in redox status in the erythrocytes and liver were reversed. The observed protective effects when rooibos and RPO were supplemented concomitantly were neither additive nor synergistic. Our results suggested that rooibos and RPO, either supplemented alone or combined, are capable of alleviating t-BHP-induced oxidative hepatotoxicity, and the mechanism of this protection may involve inhibition of lipid peroxidation and modulation of antioxidants enzymes and glutathione status. PMID:23690869

  15. Protective Effects of Rooibos (Aspalathus linearis) and/or Red Palm Oil (Elaeis guineensis) Supplementation on tert-Butyl Hydroperoxide-Induced Oxidative Hepatotoxicity in Wistar Rats

    PubMed Central

    Ajuwon, Olawale R.; Katengua-Thamahane, Emma; Van Rooyen, Jacques; Oguntibeju, Oluwafemi O.; Marnewick, Jeanine L.

    2013-01-01

    The possible protective effects of an aqueous rooibos extract (Aspalathus linearis), red palm oil (RPO) (Elaeis guineensis), or their combination on tert-butyl-hydroperoxide-(t-BHP-)induced oxidative hepatotoxicity in Wistar rats were investigated. tert-butyl hydroperoxide caused a significant (P < 0.05) elevation in conjugated dienes (CD) and malondialdehyde (MDA) levels, significantly (P < 0.05) decreased reduced glutathione (GSH) and GSH?:?GSSG ratio, and induced varying changes in activities of catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase in the blood and liver. This apparent oxidative injury was associated with histopathological changes in liver architecture and elevated levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH). Supplementation with rooibos, RPO, or their combination significantly (P < 0.05) decreased CD and MDA levels in the liver and reduced serum level of ALT, AST, and LDH. Likewise, changes observed in the activities of antioxidant enzymes and impairment in redox status in the erythrocytes and liver were reversed. The observed protective effects when rooibos and RPO were supplemented concomitantly were neither additive nor synergistic. Our results suggested that rooibos and RPO, either supplemented alone or combined, are capable of alleviating t-BHP-induced oxidative hepatotoxicity, and the mechanism of this protection may involve inhibition of lipid peroxidation and modulation of antioxidants enzymes and glutathione status. PMID:23690869

  16. Metabolism of m-tert.-butylphenyl N-methylcarbamate in insects and mice

    PubMed Central

    Douch, P. G. C.; Smith, J. N.

    1971-01-01

    The metabolism of m-tert.-butylphenyl N-methylcarbamate was studied in mice and five species of insects. Both the tert.-butyl group and the N-methyl group were hydroxylated. The major phenolic metabolite was m-(?-hydroxy-tert.-butyl)phenol, which was identified by mass spectroscopy. Significant amounts of dihydroxy compounds were formed at a constant rate from the start of the enzymic oxidation process. The considerable species variation in the yields of the different types of oxidation products suggests that N-demethylation and oxidation of the tert.-butyl groups were catalysed by different enzymes. A microsomal NADPH-dependent enzyme also catalysed the splitting of the ester link in the insecticide. PMID:4401377

  17. Isobaric vapor-liquid equilibria in the system methyl propanoate + n-butyl alcohol

    SciTech Connect

    Susial, P.; Ortega, J. . Lab. de Termodinamica y Fisicoquimica)

    1993-10-01

    Isobaric vapor-liquid equilibria were determined at 74.66, 101.32, and 127.99 kPa for binary mixtures containing methyl propanoate + n-butyl alcohol by using a dynamic still with vapor and liquid circulation. No azeotrope was detected. The data were found to be thermodynamically consistent according to the point to point test. Application of the group-contribution models ASOG, UNIFAC, and modified UNIFAC to the activity coefficients at the three pressures studied gives average errors of less than 10%, 11%, and 3%, respectively.

  18. Poly[[[diisothio­cyanato­cobalt(II)]-bis­[?-4-tert-butyl-2,6-bis­(1,2,4-triazol-1-ylmeth­yl)phenol

    PubMed Central

    Chu, Zhao-lian

    2009-01-01

    In the title compound, {[Co(NCS)2(C16H20N6O)2]·2C3H7NO·2H2O}n, each CoII ion located on an inversion center is six-coordinated by four equatorial N atoms from four different 4-tert-butyl-2,6-bis­(1,2,4-triazol-1-ylmeth­yl)phenol (L) ligands, and by two N atoms from two axial thio­cyanate anions [Co—N = 2.104?(3)–2.144?(3)?Å]. The metal centres are connected via the bidentate L ligands into two-dimensional polymeric layers parallel to bc plane. The dimethyl­formamide and solvent water mol­ecules participate in inter­molecular O—H?O and O—H?S hydrogen bonds, which consolidate the crystal packing. PMID:21582072

  19. Poly[[[diisothio-cyanato-cobalt(II)]-bis-[?-4-tert-butyl-2,6-bis-(1,2,4-triazol-1-ylmeth-yl)phenol

    PubMed

    Chu, Zhao-Lian

    2009-01-01

    In the title compound, {[Co(NCS)(2)(C(16)H(20)N(6)O)(2)]·2C(3)H(7)NO·2H(2)O}(n), each Co(II) ion located on an inversion center is six-coordinated by four equatorial N atoms from four different 4-tert-butyl-2,6-bis-(1,2,4-triazol-1-ylmeth-yl)phenol (L) ligands, and by two N atoms from two axial thio-cyanate anions [Co-N = 2.104?(3)-2.144?(3)?Å]. The metal centres are connected via the bidentate L ligands into two-dimensional polymeric layers parallel to bc plane. The dimethyl-formamide and solvent water mol-ecules participate in inter-molecular O-H?O and O-H?S hydrogen bonds, which consolidate the crystal packing. PMID:21582072

  20. Growth and characterization of 2,6-Di-tert-butyl-4-(dimethylaminomethyl)phenol single crystal by the vertical Bridgman method

    NASA Astrophysics Data System (ADS)

    Siva Bala Solanki, S.; Perumal, Rajesh Narayana; Basheer Ahamed, M.

    2015-02-01

    Single crystal of 2,6-Di-tert-butyl-4-(dimethylaminomethyl)phenol has been grown by the modified vertical Bridgman method. Single crystal X-ray diffraction studies of the crystal confirm that the material belongs to the monoclinic system and space group C2. Fourier Transform Infrared Spectroscopy (FTIR) analysis ascertains the functional group of grown crystal. Thermogravimetric and differential scanning calorimetric analyses are used to assess the thermal characteristics. The surface laser damage value was determined using Q-switched Nd:YAG laser at a wavelength of 1064 nm, which is a positive property for nonlinear optical applications. Vickers's indentation test is performed to analyze the mechanical behavior of the materials. An optical transmission study is used to compute optical band gap and cutoff wavelength. Fluorescence studies were performed to the grown crystal. The Kurtz and Perry powder technique is used to determine the second harmonic conversion efficiency of the sample.

  1. The CGP7930 analogue 2,6-di-tert-butyl-4-(3-hydroxy-2-spiropentylpropyl)-phenol (BSPP) potentiates baclofen action at GABA(B) autoreceptors.

    PubMed

    Parker, David A S; Marino, Victor; Ong, Jennifer; Puspawati, Ni Made; Prager, Rolf H

    2008-09-01

    The pharmacological actions of 2,6-di-tert-butyl-4-(3-hydroxy-2-spiropentylpropyl)-phenol (BSPP), a putative presynaptic GABA(B) receptor modulator, were examined in electrically stimulated rat neocortical brain slices preloaded with [3H]-GABA or [3H]-glutamic acid. At 10 mmol/L, BSPP inhibited the release of [3H]-GABA in the presence of baclofen, but not that of [3H]-glutamic acid. This effect was sensitive to the GABA(B) receptor antagonist (+)-(S)-5,5-dimethylmorpholinyl-2-acetic acid (Sch 50911). Alone, BSPP had no effect on the release of [3H]-GABA or [3H]-glutamic acid. It is concluded that BSPP selectively potentiates the action of baclofen at GABA(B) autoreceptors, but not heteroreceptors and may be a useful ligand to discriminate between presynaptic GABA(B) receptor subtypes. PMID:18430050

  2. Identification of hepatoprotective xanthones from the pericarps of Garcinia mangostana, guided with tert-butyl hydroperoxide induced oxidative injury in HL-7702 cells.

    PubMed

    Wang, Anqi; Liu, Qianyu; Ye, Yang; Wang, Yitao; Lin, Ligen

    2015-09-01

    Bioactivity-guided fractionation of an ethanol-soluble extract from the pericarps of Garcinia mangostana, using tert-butyl hydroperoxide (t-BHP) induced oxidative damage in human normal hepatocytes (HL-7702), led to the identification of 10 known xanthones. Among them, ?-mangostin (?-Man) exhibited the most potent activity to attenuate t-BHP induced hepatocyte injury. ?-Man significantly ameliorated t-BHP induced reactive oxygen species accumulation, mitochondrial membrane depolarization and cell nuclei morphology change in HL-7702 cells. t-BHP decreased the intracellular levels of key enzymes including glutamate oxaloacetate transaminase and glutamate pyruvate transaminase, which was totally reversed by ?-Man. Moreover, ?-Man significantly decreased the level of lipid peroxidation and increased the levels of superoxide dismutase and reduced glutathione, resulting in the alleviation of oxidative stress. The above results suggest ?-Man is a potential hepatoprotective agent against t-BHP induced oxidative injury, which may benefit the further application of G. mangostana as a health food. PMID:26189454

  3. Preparation of Langmuir-Blodgett thin films of calix[6]arenes and p-tert butyl group effect on their gas sensing properties

    NASA Astrophysics Data System (ADS)

    Ozmen, Mustafa; Ozbek, Zikriye; Bayrakci, Mevlut; Ertul, Seref; Ersoz, Mustafa; Capan, Rifat

    2015-12-01

    Organic vapor sensing properties of Langmuir-Blodgett (LB) thin films of p-tert-butyl calix[6]arene and calix[6]arene, and their certain characterization are reported in this work. LB films of these calixarenes have been characterized by contact angle measurement, quartz crystal microbalance (QCM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). QCM system was used for the measurement of sensor response against chloroform, benzene, toluene and ethanol vapors. Forming of stable monolayers was observed at the water surface using surface pressure-area isotherm graph. The results indicate that good quality, uniform LB films can be prepared with a transfer ratio of over 0.95. Due to the adsorption of vapors into the LB film structures; they yield a response to all vapors as of large, fast, and reproducible.

  4. TRANSPORT OF METHYL TERT-BUTYL ETHER THROUGH ALFALFA PLANTS. (R825549C062)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  5. 2-tert-Butyl-4-methyl-6-(1,3-oxazinan-1-ylmeth-yl)phenol.

    PubMed

    Lei, Wen-Jun; Zhan, Shu-Zhong; Ng, Seik Weng

    2010-01-01

    The title compound, C(16)H(25)NO(2), which was synthesized by a Mannich reaction route, is a rare example of an organic compound containing the six-membered oxazine ring. The ring adopts a chair conformation and the N atom is pyramidal. The N atom serves as a hydrogen-bond acceptor to the phenolic OH group. PMID:21579094

  6. 2-tert-Butyl-4-methyl-6-(1,3-oxazinan-1-ylmeth­yl)phenol

    PubMed Central

    Lei, Wen-Jun; Zhan, Shu-Zhong; Ng, Seik Weng

    2010-01-01

    The title compound, C16H25NO2, which was synthesized by a Mannich reaction route, is a rare example of an organic compound containing the six-membered oxazine ring. The ring adopts a chair conformation and the N atom is pyramidal. The N atom serves as a hydrogen-bond acceptor to the phenolic OH group. PMID:21579094

  7. 2-[Bis(pyrazol-1-yl)methyl]-4-tert-butyl-6-(phenylsulfanyl)phenol.

    PubMed

    Sylvestre, Isabelle; Kilner, Colin A; Halcrow, Malcolm A

    2005-05-01

    The title compound, C23H24N4OS, contains a highly asymmetric bifurcated intramolecular hydrogen bond between the hydroxy group and two pyrazole N atoms. The compound associates into centrosymmetric dimers in the crystal through two unique C-H...pi interactions, which are in turn linked into a (6,3)-network through an additional intermolecular C-H...N hydrogen bond. PMID:15876719

  8. IRIS Toxicological Review and Summary Documents for Methyl Tert-Butyl Ether (MTBE)

    EPA Science Inventory

    MTBE is a volatile organic chemical used to oxygenate gasoline. Oxygenated gasoline improves the exhaust emissions from gasoline engines. Since 1992 it has been used to comply with the Federal Reformulated Gasoline (begun in 1995) and Wintertime Oxygenated Fuel (begun in 1992) p...

  9. Participation of covalent modification of Keap1 in the activation of Nrf2 by tert-butylbenzoquinone, an electrophilic metabolite of butylated hydroxyanisole

    SciTech Connect

    Abiko, Yumi; Miura, Takashi; Phuc, Bui Hoang; Shinkai, Yasuhiro; Kumagai, Yoshito

    2011-08-15

    Butylated hydroxyanisole (BHA) is an antioxidant and class-2B carcinogen. It is biotransformed to tert-butylhydroquinone (TBHQ), which readily auto-oxidizes to the electrophilic metabolite tert-butylbenzoquinone (TBQ). BHA and TBHQ activate Nrf2, a transcription factor that is negatively regulated by Keap1 and plays a role in the initial response to chemicals causing oxidative or electrophilic stress, although, the exact mechanism of Nrf2 activation remains unclear. Here, we examined the role of TBQ in Nrf2 activation. Exposure of RAW264.7 cells to TBQ activated Nrf2 and up-regulated its downstream proteins; under these conditions, TBQ produced cellular reactive oxygen species (ROS). However, while pretreatment with catalase conjugated with polyethylene glycol (PEG-CAT) did not affect the TBQ-induced activation of Nrf2, the ROS generation caused by TBQ was entirely abolished by PEG-CAT, suggesting that ROS is not the dominant factor for TBQ-dependent Nrf2 activation. A click chemistry technique indicated that TBQ chemically modifies Keap1. Furthermore, ultrahigh performance liquid chromatography-tandem mass spectrometry analysis with purified Keap1 revealed that TBQ covalently binds to Keap1 through Cys23, Cys151, Cys226, and Cys368. These results suggest that TBQ derived from BHA activates Nrf2 through electrophilic modification of Keap1 rather than ROS formation. - Research Highlights: > tert-Butylbenzoquinone (TBQ) activates Nrf2 in RAW264.7 cells. > ROS is not essential factor for Nrf2 activation caused by TBQ. > TBQ covalently binds to Keap1 through reactive thiols, resulting in Nrf2 activation.

  10. IN-SITU BIOREMEDIATION OF METHYL TERTIARY BUTYL ETHER (MTBE) - ADVANCED FUEL HYDROCARBON REMEDIATION NATIONAL TEST LOCATION.

    EPA Science Inventory

    Equilon's Westhollow Technology Center teamed with Arizona State University to evaluate an in-situ process for bioremediation of methyl tertiary butyl ether (MTBE). MTBE is a gasoline additive that was introduced in fuels to reduce emission of a number of air pollutants including...

  11. REMOVAL OF METHYL T-BUTYL ETHER (MTBE) FROM WATER BY PERVAPORATION: BENCH-SCALE AND PILOT SCALE EVALUATIONS

    EPA Science Inventory

    The ability of pervaporation to remove methyl t-butyl ether (MTBE) from water was evaluated at bench- and pilot-scales. Process parameters studied included flow rate, temperature, MTBE concentration, membrane module type, and permeate pressure. Pervaporation performance was ass...

  12. DEVELOPMENT OF PHYSIOLOGICAL-BASED PHARMACOKINETIC MODEL FOR DERMAL ABSORPTION NAD PENETRATION OF METHYL TERTIARY BUTYL ETHER IN HUMANS

    EPA Science Inventory

    Background: Methyl tertiary butyl ether (MTBE) is a volatile organic chemical that is added to gasoline as an octane booster and to reduce vehicular emissions of carbon monoxide. MTBE is introduced into the environment through fuel spills, leakage of storage tanks, and evaporat...

  13. Recovery of Rhodococcus biosurfactants using methyl tertiary-butyl ether extraction.

    PubMed

    Kuyukina, M S; Ivshina, I B; Philp, J C; Christofi, N; Dunbar, S A; Ritchkova, M I

    2001-08-01

    In the present study, we proposed methyl tertiary-butyl ether (MTBE) as a solvent for extraction of biosurfactants from Rhodococcus bacterial cultures. After comparison with other well known solvent systems used for biosurfactant extraction, it was found that MTBE was able to extract crude surfactant material with high product recovery (10 g/l), efficiency (critical micelle concentration (CMC), 130-170 mg/l) and good functional surfactant characteristics (surface and interfacial tensions, 29 and 0.9 mN/m, respectively). The isolated surfactant complex contained 10% polar lipids, mostly glycolipids possessing maximal surface activity. Ultrasonic treatment of the extraction mixture increased the proportion of polar lipids in crude extract, resulting in increasing surfactant efficiency. Due to certain characteristics of MTBE, such as relatively low toxicity, biodegradability, ease of downstream recovery, low flammability and explosion safety, the use of this solvent as an extraction agent in industrial scale biosurfactant production is feasible. PMID:11412925

  14. Double-addition reaction of aryl methyl sulfones with N-tert-butylsulfinyl imines: diastereoselective and concise synthesis of 2-sulfonylated 1,3-diamines.

    PubMed

    Li, Ya; Li, Desheng; Zheng, Tao; Li, Hongsen; Ren, Xinfeng

    2014-11-10

    We report a double-addition reaction of methyl phenyl sulfone and methyl 2-pyridyl sulfone with N-tert-butylsulfinyl imines. This method provides concise access to 2-sulfonylated 1,3-anti diamines with good to excellent diastereoselectivities. This protocol has the benefit of using readily accessible starting materials and is operationally simple. PMID:25288374

  15. Highly efficient enzymatic synthesis of tert-butyl (S)-6-chloro-5-hydroxy-3-oxohexanoate with a mutant alcohol dehydrogenase of Lactobacillus kefir.

    PubMed

    He, Xiu-Juan; Chen, Shao-Yun; Wu, Jian-Ping; Yang, Li-Rong; Xu, Gang

    2015-11-01

    tert-Butyl (S)-6-chloro-5-hydroxy-3-oxohexanoate ((S)-CHOH) is a valuable chiral synthon, which is used for the synthesis of the cholesterol-lowering drugs atorvastatin and rosuvastatin. To date, only the alcohol dehydrogenases from Lactobacillus brevis (LbADH) and Lactobacillus kefir (LkADH) have demonstrated catalytic activity toward the asymmetric reduction of tert-butyl 6-chloro-3,5-dioxohexanoate (CDOH) to (S)-CHOH. Herein, a tetrad mutant of LkADH (LkTADH), A94T/F147L/L199H/A202L, was screened to be more efficient in this bioreduction process, exhibiting a 3.7- and 42-fold improvement in specific activity toward CDOH (1.27 U/mg) over LbADH (0.34 U/mg) and wild-type LkADH (0.03 U/mg), respectively. The molecular basis for the improved catalytic activity of LkTADH toward CDOH was investigated using homology modeling and docking analysis. Two major issues had a significant impact on the biocatalytic efficiency of this process, including (i) the poor aqueous stability of the substrate and (ii) partial substrate inhibition. A fed-batch strategy was successfully developed to address these issues and maintain a suitably low substrate concentration throughout the entire process. Several other parameters were also optimized, including the pH, temperature, NADP(+) concentration and cell loading. A final CDOH concentration of 427 mM (100 g/L) gave (S)-CHOH in 94 % yield and 99.5 % e.e. after a reaction time of 38 h with whole cells expressing LkTADH. The space-time yield and turnover number of NADP(+) in this process were 10.6 mmol/L/h and 16,060 mol/mol, respectively, which were the highest values ever reported. This new approach therefore represents a promising alternative for the efficient synthesis of (S)-CHOH. PMID:26004803

  16. Synthesis and properties of optically active nanostructured polymers bearing amino acid moieties by direct polycondensation of 4,4'-thiobis(2-tert-butyl-5-methylphenol) with chiral diacids.

    PubMed

    Mallakpour, Shadpour; Soltanian, Samaneh

    2012-06-01

    Four derivatives of N-trimellitylimido-L-amino acid (4a-4d) were prepared by the reaction of trimellitic anhydride (1) with the L-amino acids (2a-2d) in acetic acid as diacid monomers and were used with the aim to obtain a new family of amino acid based poly(ester-imide)s (PEI)s. The polymerization was performed by direct polycondensation of chiral diacids (4a-4d) with 4,4'-thiobis(2-tert-butyl-5-methylphenol) (5) in the presence of tosyl chloride (TsCl), pyridine and N,N-dimethyl formamide (DMF). Step-growth polymerization was carried out by varying the time of heating and the molar ratio of TsCl/diacid and the optimum conditions were achieved. The synthesized polymers were characterized by means of specific rotation experiments, FT-IR, 1H-NMR, X-ray diffraction techniques and elemental analysis. The surface morphology of the obtained polymers was studied by field emission scanning electron microscopy. The result showed nanostructure morphology of the resulting polymers. The obtained PEIs were soluble in polar aprotic solvents such as DMF, N,N-dimethyl acetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and protic solvents such as sulfuric acid. Thermal stability and the weight-loss behavior of the PEIs were studied by thermal gravimetric analysis (TGA) techniques. TGA showed that the 10% weight loss temperature in a nitrogen atmosphere was more than 402°C, therefore they had useful levels of thermal stability associated with excellent solubility. PMID:21691754

  17. Combined use of l-alanine tert butyl ester lactate and trimethyl-?-cyclodextrin for the enantiomeric separations of 2-arylpropionic acids nonsteroidal anti-inflammatory drugs.

    PubMed

    Mavroudi, Maria C; Kapnissi-Christodoulou, Constantina P

    2015-10-01

    In this study, a new CE method, employing a binary system of trimethyl-?-CD (TM-?-CD) and a chiral amino acid ester-based ionic liquid (AAIL), was developed for the chiral separation of seven 2-arylpropionic acid nonsteroidal anti-inflammatory drugs (NSAIDs). In particular, the enantioseparation of ibuprofen, ketoprofen, carprofen, indoprofen, flurbiprofen, naproxen, and fenoprofen was improved significantly by supporting the BGE with the chiral AAIL l-alanine tert butyl ester lactate (l-AlaC4 Lac). Parameters, such as concentrations of TM-?-CD and l-AlaC4 Lac, and buffer pH, were systematically examined in order to optimize the chiral separation of each NSAID. It was observed that the addition of the AAIL into the BGE improved both resolution and efficiency significantly. After optimization of separation conditions, baseline separation (Rs >1.5) of five of the analytes was achieved in less than 11 min, while the resolution of ibuprofen and flurbiprofen was approximately 1.2. The optimized enantioseparation conditions for all analytes involve a BGE of 5 mM sodium acetate/acetic acid (pH 5.0), an applied voltage of 30 kV, and a temperature of 20°C. In addition, the results obtained by computing the %-RSD values of the EOF and the two enantiomer peaks, demonstrated excellent run-to-run, batch-to-batch, and day-to-day reproducibilities. PMID:26080944

  18. Synthesis and antibacterial activity of tert-butyl [1-benzyl-2[(4-aryl-2-thiazolyl)hydrazono]ethyl]carbamate derivatives.

    PubMed

    Turan-Zitouni, Gülhan; Fehrentz, Jean-Alain; Chevallet, Pierre; Martinez, Jean; Kaplancikli, Zafer Asim; Ozdemir, Ahmet; Arslanyolu, Muhittin; Yildiz, Mehmet Taha

    2007-06-01

    The increasing clinical importance of drug-resistant fungal and bacterial pathogens has lent additional urgency to microbiological research and new antibacterial compound development. For this purpose, new tert-butyl[1-benzyl-2[(4-aryl-2-thiazolyl)hydrazono]ethyl]carbamate derivatives were synthesized and evaluated for antibacterial activity. The reaction of Boc-L-phenylalaninal with thiosemicarbazide gave the thiosemicarbazone which furnished the title compounds by reaction with phenacyl bromides. The newly synthesized compounds were screened for antibacterial activity and toxicity. While microdilution broth susceptibility assay was used for the antibacterial activity evaluation of the compounds against the strains E. coli (NRRL B-3704), M. luteus (NRRL B-4375), B. cereus (NRRL B-3711), P. aeruginosa (NRRL B-23), and S. fecalis (NRRL B-14617), the Artemia salina 96-well assay was used to determine cytotoxicities of the compounds. Observations obtained from the bioassays showed that some of the compounds are highly active against E. coli, M. luteus, and B. cereus when compared with the control agent and showed low toxicity. PMID:17562564

  19. Stability of fluctuating and transient aggregates of amphiphilic solutes in aqueous binary mixtures: Studies of dimethylsulfoxide, ethanol, and tert-butyl alcohol

    NASA Astrophysics Data System (ADS)

    Banerjee, Saikat; Bagchi, Biman

    2013-10-01

    In aqueous binary mixtures, amphiphilic solutes such as dimethylsulfoxide (DMSO), ethanol, tert-butyl alcohol (TBA), etc., are known to form aggregates (or large clusters) at small to intermediate solute concentrations. These aggregates are transient in nature. Although the system remains homogeneous on macroscopic length and time scales, the microheterogeneous aggregation may profoundly affect the properties of the mixture in several distinct ways, particularly if the survival times of the aggregates are longer than density relaxation times of the binary liquid. Here we propose a theoretical scheme to quantify the lifetime and thus the stability of these microheterogeneous clusters, and apply the scheme to calculate the same for water-ethanol, water-DMSO, and water-TBA mixtures. We show that the lifetime of these clusters can range from less than a picosecond (ps) for ethanol clusters to few tens of ps for DMSO and TBA clusters. This helps explaining the absence of a strong composition dependent anomaly in water-ethanol mixtures but the presence of the same in water-DMSO and water-TBA mixtures.

  20. Discovery of the development candidate N-tert-butyl nodulisporamide: a safe and efficacious once monthly oral agent for the control of fleas and ticks on companion animals.

    PubMed

    Meinke, Peter T; Colletti, Steven L; Fisher, Michael H; Wyvratt, Matthew J; Shih, Thomas L; Ayer, Michelle B; Li, Chunshi; Lim, Julie; Ok, Dong; Salva, Steve; Warmke, Lynn M; Zakson, Michelle; Michael, Bruce F; Demontigny, Pierre; Ostlind, Dan A; Fink, David; Drag, Marlene; Schmatz, Dennis M; Shoop, Wesley L

    2009-06-11

    Nodulisporic acid A (1) is a structurally complex fungal metabolite that exhibits systemic efficacy against fleas via modulation of an invertebrate specific glutamate-gated ion channel. In order to identify a nodulisporamide suitable for monthly oral dosing in dogs, a library of 335 nodulisporamides was examined in an artificial flea feeding system for intrinsic systemic potency as well as in a mouse/bedbug assay for systemic efficacy and safety. A cohort of 66 nodulisporamides were selected for evaluation in a dog/flea model; pharmacokinetic analysis correlated plasma levels with flea efficacy. These efforts resulted in the identification of the development candidate N-tert-butyl nodulisporamide (3) as a potent and efficacious once monthly oral agent for the control of fleas and ticks on dogs and cats which was directly compared to the topical agents fipronil and imidacloprid, with favorable results obtained. Multidose studies over 3 months confirmed the in vivo ectoparasiticidal efficacy and established that 3 lacked overt mammalian toxicity. Tissue distribution studies in mice using [(14)C]-labeled 3 indicate that adipose beds serve as ligand depots, contributing to the long terminal half-lives of these compounds. PMID:19445514

  1. Effects of colored and noncolored phenolics of Echium plantagineum L. bee pollen in Caco-2 cells under oxidative stress induced by tert-butyl hydroperoxide.

    PubMed

    Sousa, Carla; Moita, Eduarda; Valentão, Patrícia; Fernandes, Fátima; Monteiro, Pedro; Andrade, Paula B

    2015-02-25

    Bee pollen is used as a dietary supplement, being promoted as a health food. Echium plantagineum L. bee pollen fractions enriched in flavonols (fraction I) or anthocyanins (fraction II) and the whole extract were characterized by HPLC-DAD. Both in the whole extract and in fraction II seven flavonols and five anthocyanins were identified, while fraction I contained six flavonols (in higher levels than fraction II) and small amounts of petunidin-3-O-rutinoside. Antioxidant capacity was evaluated in Caco-2 cells under oxidative stress induced by tert-butyl hydroperoxide (t-BHP). Fraction I pre-exposure imparted a tendency to protect cells, while fraction II and the whole extract aggravated t-BHP toxicity at some concentrations. The protective effects seem to be correlated with the levels of total glutathione, while no correlation between cellular viability and reactive species was seen. The extracts displayed no significant effect on antioxidant enzymes activity. Overall, anthocyanins seem to abrogate the antioxidant potential of flavonoid-rich extracts. PMID:25642978

  2. Effects of Consumption of Rooibos (Aspalathus linearis) and a Rooibos-Derived Commercial Supplement on Hepatic Tissue Injury by tert-Butyl Hydroperoxide in Wistar Rats

    PubMed Central

    Canda, B. D.; Oguntibeju, O. O.; Marnewick, J. L.

    2014-01-01

    This study investigated the antioxidative effect of rooibos herbal tea and a rooibos-derived commercial supplement on tert-butyl hydroperoxide- (t-BHP-) induced oxidative stress in the liver. Forty male Wistar rats consumed fermented rooibos, unfermented rooibos, a rooibos-derived commercial supplement, or water for 10 weeks, while oxidative stress was induced during the last 2 weeks via intraperitoneal injection of 30?µmole of t-BHP per 100?g body weight. None of the beverages impaired the body weight gain of the respective animals. Rats consuming the rooibos-derived commercial supplement had the highest (P < 0.05) daily total polyphenol intake (169?mg/day) followed by rats consuming the unfermented rooibos (93.4?mg/day) and fermented rooibos (73.1?mg/day). Intake of both the derived supplement and unfermented rooibos restored the t-BHP-induced reduction and increased (P < 0.05) the antioxidant capacity status of the liver, while not impacting on lipid peroxidation. The rooibos herbal tea did not affect the hepatic antioxidant enzymes, except fermented rooibos that caused a decrease (P < 0.05) in superoxide dismutase activity. This study confirms rooibos herbal tea as good dietary antioxidant sources and, in conjunction with its many other components, offers a significantly enhanced antioxidant status of the liver in an induced oxidative stress situation. PMID:24738022

  3. Effects of consumption of rooibos (Aspalathus linearis) and a rooibos-derived commercial supplement on hepatic tissue injury by tert-butyl hydroperoxide in Wistar rats.

    PubMed

    Canda, B D; Oguntibeju, O O; Marnewick, J L

    2014-01-01

    This study investigated the antioxidative effect of rooibos herbal tea and a rooibos-derived commercial supplement on tert-butyl hydroperoxide- (t-BHP-) induced oxidative stress in the liver. Forty male Wistar rats consumed fermented rooibos, unfermented rooibos, a rooibos-derived commercial supplement, or water for 10 weeks, while oxidative stress was induced during the last 2 weeks via intraperitoneal injection of 30 µmole of t-BHP per 100 g body weight. None of the beverages impaired the body weight gain of the respective animals. Rats consuming the rooibos-derived commercial supplement had the highest (P < 0.05) daily total polyphenol intake (169 mg/day) followed by rats consuming the unfermented rooibos (93.4 mg/day) and fermented rooibos (73.1 mg/day). Intake of both the derived supplement and unfermented rooibos restored the t-BHP-induced reduction and increased (P < 0.05) the antioxidant capacity status of the liver, while not impacting on lipid peroxidation. The rooibos herbal tea did not affect the hepatic antioxidant enzymes, except fermented rooibos that caused a decrease (P < 0.05) in superoxide dismutase activity. This study confirms rooibos herbal tea as good dietary antioxidant sources and, in conjunction with its many other components, offers a significantly enhanced antioxidant status of the liver in an induced oxidative stress situation. PMID:24738022

  4. Cooperative reduction by Ln(2+) and Cp*(-) ions: synthesis and properties of Sm, Eu, and Yb complexes with 3,6-di-tert-butyl-o-benzoquinone.

    PubMed

    Pushkarevsky, Nikolay A; Ogienko, Mikhail A; Smolentsev, Anton I; Novozhilov, Igor N; Witt, Alexander; Khusniyarov, Marat M; Cherkasov, Vladimir K; Konchenko, Sergey N

    2016-01-01

    The first examples of samarium, europium, and ytterbium complexes with 3,6-di-tert-butyl-o-benzoquinone (3,6-dbbq) in the form of catecholate have been obtained by reactions of the quinone with the corresponding lanthanocenes, (n = 1 or 2) in solution. In the course of the reactions lanthanide ions lose one or two Cp* ligands, which take part in reduction of a quinone molecule into a catecholate anion (dbcat, 2-). As a result of the reactions, Sm and Yb clearly yield dimeric complexes [(LnCp*)2(dbcat)2], where each Ln ion loses one Cp* ligand. Eu forms a trimeric complex [(EuCp*)(Eu·thf)2(dbcat)3], in which one Eu ion is coordinated by one Cp* ligand, while two Eu ions have lost all Cp* ligands and are coordinated by THF molecules instead. Magnetic properties corroborate the assignment of oxidation states made on the basis of single-crystal X-ray diffraction: all the quinone ligands are present in the catecholate state; both Sm/Yb ions in the dimers are in the +3 oxidation state, whereas the Eu trimer contains two Eu(ii) and one Eu(iii) ions. Cyclovoltammetry studies show the presence of two reversible oxidation waves for all complexes, presumably concerned with the redox transitions of the dbcat ligands. PMID:26674171

  5. Evaluation of ethyl tert-butyl ether biodegradation in a contaminated aquifer by compound-specific isotope analysis and in situ microcosms.

    PubMed

    Bombach, Petra; Nägele, Norbert; Rosell, Mònica; Richnow, Hans H; Fischer, Anko

    2015-04-01

    Ethyl tert-butyl ether (ETBE) is an upcoming groundwater pollutant in Europe whose environmental fate has been less investigated, thus far. In the present study, we investigated the in situ biodegradation of ETBE in a fuel-contaminated aquifer using compound-specific stable isotope analysis (CSIA), and in situ microcosms in combination with total lipid fatty acid (TLFA)-stable isotope probing (SIP). In a first field investigation, CSIA revealed insignificant carbon isotope fractionation, but low hydrogen isotope fractionation of up to +14‰ along the prevailing anoxic ETBE plume suggesting biodegradation of ETBE. Ten months later, oxygen injection was conducted to enhance the biodegradation of petroleum hydrocarbons (PH) at the field site. Within the framework of this remediation measure, in situ microcosms loaded with [(13)C6]-ETBE (BACTRAP(®)s) were exposed for 119 days in selected groundwater wells to assess the biodegradation of ETBE by TLFA-SIP under the following conditions: (i) ETBE as main contaminant; (ii) ETBE as main contaminant subjected to oxygen injection; (iii) ETBE plus other PH; (iv) ETBE plus other PH subjected to oxygen injection. Under all conditions investigated, significant (13)C-incorporation into microbial total lipid fatty acids extracted from the in situ microcosms was found, providing clear evidence of ETBE biodegradation. PMID:25559863

  6. Fluctuating micro-heterogeneity in water - tert-butyl alcohol mixtures and lambda-type divergence of the mean cluster size with phase transition-like multiple anomalies

    E-print Network

    Saikat Banerjee; Jonathan Furtado; Biman Bagchi

    2014-02-20

    Water - tert-butyl alcohol (TBA) binary mixture exhibits a large number of thermodynamic and dynamic anomalies. These anomalies are observed at surprisingly low TBA mole fraction, with $x_{\\text{TBA}} \\approx 0.03 - 0.07$. We demonstrate here that the origin of the anomalies lies in the local structural changes that occur due to self-aggregation of TBA molecules. We observe a percolation transition of the TBA molecules at $x_{\\text{TBA}} \\approx 0.05$. We note that "islands" of TBA clusters form even below this mole fraction, while a large spanning cluster emerges above that mole fraction. At this percolation threshold, we observe a lambda-type divergence in the fluctuation of the size of the largest TBA cluster, reminiscent of a critical point. Alongside, the structure of water is also perturbed, albeit weakly, by the aggregation of TBA molecules. There is a monotonic decrease in the tetrahedral order parameter of water, while the dipole moment correlation shows a weak non-linearity. Interestingly, water molecules themselves exhibit a reverse percolation transition at higher TBA concentration, $x_{\\text{TBA}} \\approx 0.45$, where large spanning water clusters now break-up into small clusters. This is accompanied by significant divergence of the fluctuations in the size of largest water cluster. This second transition gives rise to another set of anomalies around. Both the percolation transitions can be regarded as manifestations of Janus effect at small molecular level.

  7. Fluctuating micro-heterogeneity in water–tert-butyl alcohol mixtures and lambda-type divergence of the mean cluster size with phase transition-like multiple anomalies

    SciTech Connect

    Banerjee, Saikat; Furtado, Jonathan; Bagchi, Biman

    2014-05-21

    Water–tert-butyl alcohol (TBA) binary mixture exhibits a large number of thermodynamic and dynamic anomalies. These anomalies are observed at surprisingly low TBA mole fraction, with x{sub TBA} ? 0.03–0.07. We demonstrate here that the origin of the anomalies lies in the local structural changes that occur due to self-aggregation of TBA molecules. We observe a percolation transition of the TBA molecules at x{sub TBA} ? 0.05. We note that “islands” of TBA clusters form even below this mole fraction, while a large spanning cluster emerges above that mole fraction. At this percolation threshold, we observe a lambda-type divergence in the fluctuation of the size of the largest TBA cluster, reminiscent of a critical point. Alongside, the structure of water is also perturbed, albeit weakly, by the aggregation of TBA molecules. There is a monotonic decrease in the tetrahedral order parameter of water, while the dipole moment correlation shows a weak nonlinearity. Interestingly, water molecules themselves exhibit a reverse percolation transition at higher TBA concentration, x{sub TBA} ? 0.45, where large spanning water clusters now break-up into small clusters. This is accompanied by significant divergence of the fluctuations in the size of largest water cluster. This second transition gives rise to another set of anomalies around. Both the percolation transitions can be regarded as manifestations of Janus effect at small molecular level.

  8. Solvent extraction of technetium from alkaline waste media using bis-4,4{prime}(5{prime})[(tert-butyl)cyclohexano]-18-crown-6

    SciTech Connect

    Bonnesen, P.V.; Presley, D.J.; Moyer, B.A.

    1995-07-01

    The crown ether bis-4,4`(5`)[(tert-butyl)cyclohexano]-18-crown-6 can be utilized in a solvent-extraction process for the removal of technetium as pertechnetate ion, TcO{sub 4}{sup {minus}} from solutions simulating highly radioactive alkaline defense wastes (``tank wastes``) stored at several sites in the United States. The process employs non-halogenated and non-volatile diluents and modifiers and includes an efficient stripping procedure using only water. More than 95% of the pertechnetate present at 6 {times} 10{sup {minus}5} M in Melton Valley (Oak Ridge, TN) and Hanford (Washington) tank-waste simulants was removed following two cross-current extraction contacts using 0.02 M bis-4,4`(5`)[(tertbutyl)cyclohexano]- 18-crown-6 in 2:1 vol/vol TBP/Isopar{reg_sign} M diluent at 25 C. Similarly, for both simulants, more than 98% of the pertechnetate contained in the solvent was back-extracted following two cross-current stripping contacts using deionized water.

  9. Low-temperature CVD of iron, cobalt, and nickel nitride thin films from bis[di(tert-butyl)amido]metal(II) precursors and ammonia

    SciTech Connect

    Cloud, Andrew N.; Abelson, John R.; Davis, Luke M.; Girolami, Gregory S.

    2014-03-15

    Thin films of late transition metal nitrides (where the metal is iron, cobalt, or nickel) are grown by low-pressure metalorganic chemical vapor deposition from bis[di(tert-butyl)amido]metal(II) precursors and ammonia. These metal nitrides are known to have useful mechanical and magnetic properties, but there are few thin film growth techniques to produce them based on a single precursor family. The authors report the deposition of metal nitride thin films below 300?°C from three recently synthesized M[N(t-Bu){sub 2}]{sub 2} precursors, where M?=?Fe, Co, and Ni, with growth onset as low as room temperature. Metal-rich phases are obtained with constant nitrogen content from growth onset to 200?°C over a range of feedstock partial pressures. Carbon contamination in the films is minimal for iron and cobalt nitride, but similar to the nitrogen concentration for nickel nitride. X-ray photoelectron spectroscopy indicates that the incorporated nitrogen is present as metal nitride, even for films grown at the reaction onset temperature. Deposition rates of up to 18?nm/min are observed. The film morphologies, growth rates, and compositions are consistent with a gas-phase transamination reaction that produces precursor species with high sticking coefficients and low surface mobilities.

  10. Adsorption of methyl tertiary butyl ether on granular zeolites: Batch and column studies.

    PubMed

    Abu-Lail, Laila; Bergendahl, John A; Thompson, Robert W

    2010-06-15

    Methyl tertiary butyl ether (MTBE) has been shown to be readily removed from water with powdered zeolites, but the passage of water through fixed-beds of very small powdered zeolites produces high friction losses not encountered in flow through larger sized granular materials. In this study, equilibrium and kinetic adsorption of MTBE onto granular zeolites, a coconut shell granular activated carbon (CS-1240), and a commercial carbon adsorbent (CCA) sample was evaluated. In addition, the effect of natural organic matter (NOM) on MTBE adsorption was evaluated. Batch adsorption experiments determined that ZSM-5 was the most effective granular zeolite for MTBE adsorption. Further equilibrium and kinetic experiments verified that granular ZSM-5 is superior to CS-1240 and CCA in removing MTBE from water. No competitive adsorption effects between NOM and MTBE were observed for adsorption to granular ZSM-5 or CS-1240, however there was competition between NOM and MTBE for adsorption onto the CCA granules. Fixed-bed adsorption experiments for longer run times were performed using granular ZSM-5. The bed depth service time model (BDST) was used to analyze the breakthrough data. PMID:20153106

  11. Gastroprotective Activity of Ethyl-4-[(3,5-di-tert-butyl-2-hydroxybenzylidene) Amino]benzoate against Ethanol-Induced Gastric Mucosal Ulcer in Rats

    PubMed Central

    Halabi, Mohammed Farouq; Shakir, Raied Mustafa; Bardi, Daleya Abdulaziz; Al-Wajeeh, Nahla Saeed; Ablat, Abdulwali; Hassandarvish, Pouya; Hajrezaie, Maryam; Norazit, Anwar; Abdulla, Mahmood Ameen

    2014-01-01

    Background The study was carried out to determine the cytotoxic, antioxidant and gastro-protective effect of ethyl-4-[(3,5-di-tert-butyl-2-hydroxybenzylid ene)amino] benzoate (ETHAB) in rats. Methodology/Principal Findings The cytotoxic effect of ETHAB was assessed using a MTT cleavage assay on a WRL68 cell line, while its antioxidant activity was evaluated in vitro. In the anti-ulcer study, rats were divided into six groups. Group 1 and group 2 received 10% Tween 20 (vehicle). Group 3 received 20 mg/kg Omeprazole. Groups 4, 5 and 6 received ETHAB at doses of 5, 10, and 20 mg/kg, respectively. After an hour, group 1 received the vehicle. Groups 2–6 received absolute ethanol to induce gastric mucosal lesions. In the WRL68 cell line, an IC50 of more than 100 µg/mL was observed. ETHAB results showed antioxidant activity in the DPPH, FRAP, nitric oxide and metal chelating assays. There was no acute toxicity even at the highest dosage (1000 mg/kg). Microscopy showed that rats pretreated with ETHAB revealed protection of gastric mucosa as ascertained by significant increases in superoxide dismutase (SOD), pH level, mucus secretion, reduced gastric lesions, malondialdehyde (MDA) level and remarkable flattened gastric mucosa. Histologically, pretreatment with ETHAB resulted in comparatively better gastric protection, due to reduction of submucosal edema with leucocyte infiltration. PAS staining showed increased intensity in uptake of Alcian blue. In terms of immunohistochemistry, ETHAB showed down-expression of Bax proteins and over-expression of Hsp70 proteins. Conclusion/Significance The gastroprotective effect of ETHAB may be attributed to antioxidant activity, increased gastric wall mucus, pH level of gastric contents, SOD activity, decrease in MDA level, ulcer area, flattening of gastric mucosa, reduction of edema and leucocyte infiltration of the submucosal layer, increased PAS staining, up-regulation of Hsp70 protein and suppressed expression of Bax. Key words: ethyl 4-(3, 5-di-ter-butyl-2-hydroxybenzylamino) benzoate; toxicity; antioxidant; gastric-ulcer; anti-ulcer; histology; immunohistochemistry. PMID:24800807

  12. Simultaneous determination of organotin compounds in textiles by gas chromatography-flame photometry following liquid/liquid partitioning with tert-butyl ethyl ether after reflux-extraction.

    PubMed

    Hamasaki, Tetsuo

    2013-10-15

    A rapid and relatively clean method for determining six organotin compounds (OtC) in textile goods with a gas chromatograph equipped with a conventional flame photometric detector (GC-FPD) has been developed. After the reflux-extraction to use methanol containing 1% (v/v) of hydrochloric acid, five hydrophobic OtC (e.g. tributyltin: TBT) and slightly less hydrophobic dibutyltin (DBT) could be drawn out through partitioning between the methanolic buffer solution and tert-butyl ethyl ether instead of hazardous dichloromethane, of which usage is provided by the official-methods notified in Japan, and following the ethylation procedure to use sodium tetraethylborate, the OtC were determined with the GC-FPD. The recoveries of DBT, TBT, tetrabutyltin, triphenyltin, dioctyltin, and trioctyltin from textile products (cloth diaper, socks, and undershirt) were 60-77, 89-98, 86-94, 71-78, 85-109, and 70-79% respectively, and their coefficients of variation were 2.5-16.5%. Calibration curves for OtC were linear (0.01-0.20 ?g as Sn mL(-1)), and the correlation coefficients were 0.9922-1.0000. Their detection limits were estimated to be 2.7-9.7 n gas Sn g(-1). These data suggested that this method would be applicable to their simultaneous determination. Five retailed textile goods were analyzed by this proposed method, and 0.013-0.65 µg as Sn g(-1) of OtC (e.g. DBT) were determined in three. Moreover, a possibility that various OtC including non-targeted species in textile would be specifically detected by applying the studying speciation-technique of controlling signal intensity-flame fuel gas pressures of the GC-FPD was found. PMID:24054605

  13. Relationship between sublethal injury and microbial inactivation by the combination of high hydrostatic pressure and citral or tert-butyl hydroquinone.

    PubMed

    Somolinos, Maria; García, Diego; Pagán, Rafael; Mackey, Bernard

    2008-12-01

    The aim was to investigate (i) the occurrence of sublethal injury in Listeria monocytogenes, Escherichia coli, and Saccharomyces cerevisiae after high hydrostatic pressure (HHP) treatment as a function of the treatment medium pH and composition and (ii) the relationship between the occurrence of sublethal injury and the inactivating effect of a combination of HHP and two antimicrobial compounds, tert-butyl hydroquinone (TBHQ) and citral. The three microorganisms showed a high proportion of sublethally injured cells (up to 99.99% of the surviving population) after HHP. In E. coli and L. monocytogenes, the extent of inactivation and sublethal injury depended on the pH and the composition of the treatment medium, whereas in S. cerevisiae, inactivation and sublethal injury were independent of medium pH or composition under the conditions tested. TBHQ alone was not lethal to E. coli or L. monocytogenes but acted synergistically with HHP and 24-h refrigeration, resulting in a viability decrease of >5 log(10) cycles of both organisms. The antimicrobial effect of citral depended on the microorganism and the treatment medium pH. Acting alone for 24 h under refrigeration, 1,000 ppm of citral caused a reduction of 5 log(10) cycles of E. coli at pH 7.0 and almost 3 log(10) cycles of L. monocytogenes at pH 4.0. The combination of citral and HHP also showed a synergistic effect. Our results have confirmed that the detection of sublethal injury after HHP may contribute to the identification of those treatment conditions under which HHP may act synergistically with other preserving processes. PMID:18952869

  14. Copper(ii) tetrafluoroborate complexes with the N(3),N(4)-bridging coordination of 1-(tert-butyl)-1H-tetrazole: synthesis, crystal structure and magnetic properties.

    PubMed

    Degtyarik, Mikhail M; Lyakhov, Alexander S; Ivashkevich, Ludmila S; Matulis, Vitaly E; Matulis, Vadim E; Gruschinski, Sina; Voitekhovich, Sergei V; Kersting, Berthold; Ivashkevich, Oleg A

    2015-11-14

    1-(tert-Butyl)-1H-tetrazole (L) reacts with copper(ii) tetrafluoroborate hexahydrate to give the complexes [Cu2L8(H2O)2](BF4)4 (1) or [Cu3L6(H2O)6](BF4)6 (2) depending on the reaction conditions. These complexes, as well as compound L, were characterized using single crystal X-ray analysis. Complex 1 was found to comprise a dinuclear complex cation [Cu2L8(H2O)2](4+) (the Ci symmetry point group), with six tetrazole ligands L showing monodentate N(4)-coordination, and two ligands L providing two tetrazole ring N(3),N(4) bridges between the copper(ii) cations; water molecules complete the distorted octahedral coordination of the metal ions. Complex 2 includes a linear trinuclear complex cation [Cu3L6(H2O)6](6+) (the S6 symmetry point group), in which neighbouring copper(ii) cations are linked by three ligands L via tetrazole ring N(3),N(4) bridges; central and terminal metal ions show octahedral CuN6 and CuN3O3 coordination cores, respectively. The temperature-dependent magnetic susceptibility measurements of complex 2 revealed that the copper(ii) ions were weakly ferromagnetically coupled showing a coupling constant J of 2.2 cm(-1) {H = -2J(S1S2 + S2S3)}. The quantum-chemical investigation of the electronic structure and basicity of ligand L was carried out. PMID:26442910

  15. Protection against oxidative damage to CNS by alpha-phenyl-tert-butyl nitrone (PBN) and other spin-trapping agents: A novel series of nonlipid free radical scavengers

    SciTech Connect

    Carney, J.M.; Floyd, R.A. )

    1991-01-01

    Brain is extremely susceptible to oxidative damage. Utilizing a series of novel approaches, the authors have demonstrated that oxidative damage occurs during an ischemia/reperfusion insult (IRI) to brain. Thus, they have demonstrated that an IRI to Mongolian gerbil brain results in: (1) an enhanced rate of salicylate hydroxylation, implicating an increased flux of hydroxyl free radicals; (2) an enhanced flux of free radicals as determined by spin-trapping; (3) an enhanced level of endogenous protein oxidation; (4) a decrease in glutamine synthetase (GS) activity, an enzyme very sensitive to oxidative damage; and (5) demonstration of protection from an IRI by administering the spin-trapping agent alpha-phenyl-tert-butyl nitrone (PBN). The novel observation that PBN offers protection from the lethality brought on by a brain IRI appears to be clearly linked to the ability of the administered spin-trap to inhibit oxidative damage as evidenced by the decreased amount of brain protein oxidation and the prevention of an IRI-mediated loss of GS activity in treated animals. Aged gerbils are more sensitive to the lethal action of a brain IRI than younger animals, but they are protected by PBN administration as are the younger animals. Older gerbils have a significantly higher level of oxidized protein in the brain. Older gerbils have decreased activities of GS and neutral protease, the enzyme that removes oxidized protein, than younger animals. Chronic twice daily administration of PBN (32 mg/kg) for 14 days to older animals significantly lowered brain oxidized protein levels and raised GS and neutral protease activity to those observed in younger animals. Cessation of PBN administration resulted in a time-dependent restoration of protein oxidation levels and enzyme activities back to those observed prior to spin-trap administration.

  16. Disposition of 2,6-di-tert-butyl-4-nitrophenol (DBNP), a submarine atmosphere contaminant, in male Sprague-Dawley rats.

    PubMed

    Still, Kenneth R; Jung, Anne E; Ritchie, Glenn D; Jederberg, Warren W; Wilfong, Erin R; Briggs, G Bruce; Arfsten, Darryl P

    2005-07-01

    The phenol 2,6-di-tert-butyl-4-nitrophenol (DBNP) is a contaminant found onboard submarines and is formed by the nitration of an antioxidant present in turbine lubricating oil TEP 2190. DBNP has been found on submarine interior surfaces, on eating utensils and dishes, and on the skin of submariners. DBNP exposure is a potential health concern because it is an uncoupler of mitochondrial oxidative phosphorylation. Adult male rats were dosed once by oral gavage with 15 or 40 mg/kg DBNP mixed with 14C-DBNP in kanola oil and 0.8% v/v DMSO (n = 16/group). The distribution of 14C in major tissues was measured over time for up to 240 h post-dose. Unexpectedly, 6/16 (40%) of the rats gavaged with 40 mg/kg DBNP died within 24 h of dosing. Prostration, no auditory startle response, reduced locomotor activity, and muscular rigidity persisted in survivors for up to 8 days after dosing. For animals dosed with 15 mg/kg DBNP, radioactivity levels were significantly elevated in the following tissues 24h after dosing: fat>liver>kidneys>heart>lungs>brain>striated muscle>spleen. Radioactivity levels were elevated for fat, liver, kidney, heart, and lungs of animals euthanized 144 h post-dosing and in the liver of animals euthanized 240 h post-dosing. These findings suggest that DBNP may accumulate in the body as a result of continuous or repeat exposures of short interval to DBNP. PMID:15910791

  17. Simultaneous Analysis of Tertiary Butylhydroquinone and 2-tert-Butyl-1,4-benzoquinone in Edible Oils by Normal-Phase High-Performance Liquid Chromatography.

    PubMed

    Li, Jun; Bi, Yanlan; Liu, Wei; Sun, Shangde

    2015-09-30

    During the process of antioxidation of tertiary butylhydroquinone (TBHQ) in oil and fat systems, 2-tert-butyl-1,4-benzoquinone (TQ) can be formed. The toxicity of TQ was much more than that of TBHQ. In the work, a normal-phase high-performance liquid chromatography (NP-HPLC) method for the accurate and simultaneous detection of TBHQ and TQ in edible oils was investigated. A C18 column was used to separate TBHQ and TQ, and the gradient elution solutions consisted of n-hexane containing 5% ethyl acetate and n-hexane containing 5% isopropanol. The ultraviolet (UV) detector was set at dual wavelength mode (280 nm for TBHQ and 310 nm for TQ). The column temperature was 30 °C. Before the NP-HPLC analysis, TBHQ and TQ were first extracted by methanol, subjected to vortex treatment, and then filtered through a 0.45 ?m membrane filter. Results showed that linear ranges of TBHQ and TQ were both within 0.10-500.00 ?g/mL (R(2) > 0.9999). The limit of detection (LOD) and limit of quantification (LOQ) of TBHQ and TQ were below 0.30 and 0.91 ?g/mL and below 0.10 and 0.30 ?g/mL, respectively. The recoveries of TBHQ and TQ were 98.92-102.34 and 96.28-100.58% for soybean oil and 96.11-99.42 and 98.83-99.24% for lard, respectively. These results showed that NP-HPLC can be successfully used to analyze simultaneously TBHQ and TQ in the oils and fats. PMID:26365419

  18. Synthesis, spectroscopy, magnetic and redox behaviors of copper(II) complexes with tert-butylated salen type ligands bearing bis(4-aminophenyl)ethane and bis(4-aminophenyl)amide backbones

    NASA Astrophysics Data System (ADS)

    Kasumov, Veli T.; Yerli, Yusuf; Kutluay, Aysegul; Aslanoglu, Mehmet

    2013-03-01

    New salen type ligands, N,N'-bis(X-3-tert-butylsalicylidene)-4,4'-ethylenedianiline [(X = H (1), 5-tert-butyl (2)] and N,N'-bis(X-3-tert-butylsalicylidene)-4,4'-amidedianiline [X = H (3), 5-tert (4)] and their copper(II) complexes 5-8, have been synthesized. Their spectroscopic (IR, 1H NMR, UV/vis, ESR) properties, as well as magnetic and redox-reactivity behavior are reported. IR spectra of 7 and 8 indicate the coordination of amide oxygen atoms of 3 and 4 ligands to Cu(II). The solid state ESR spectra of 5-8 exhibits less informative exchange narrowed isotropic or anisotropic signals with weak unresolved low field patterns. The magnetic moments of 5 (2.92 ?B per CuII) and 6 (2.79 ?B per CuII) are unusual for copper(II) complexes and considerably higher than those for complexes 7 and 8. Cryogenic measurements (300-10 K) show weak antiferromagnetic exchange interactions between the copper(II) centers in complexes 6 and 8. The results of electrochemical and chemical redox-reactivity studies are discussed.

  19. Discovery of N-(2,4-di-tert-butyl-5-hydroxyphenyl)-4-oxo-1,4-dihydroquinoline-3-carboxamide (VX-770, ivacaftor), a potent and orally bioavailable CFTR potentiator.

    PubMed

    Hadida, Sabine; Van Goor, Fredrick; Zhou, Jinglan; Arumugam, Vijayalaksmi; McCartney, Jason; Hazlewood, Anna; Decker, Caroline; Negulescu, Paul; Grootenhuis, Peter D J

    2014-12-11

    Quinolinone-3-carboxamide 1, a novel CFTR potentiator, was discovered using high-throughput screening in NIH-3T3 cells expressing the F508del-CFTR mutation. Extensive medicinal chemistry and iterative structure-activity relationship (SAR) studies to evaluate potency, selectivity, and pharmacokinetic properties resulted in the identification of N-(2,4-di-tert-butyl-5-hydroxyphenyl)-4-oxo-1,4-dihydroquinoline-3-carboxamide (VX-770, 48, ivacaftor), an investigational drug candidate approved by the FDA for the treatment of CF patients 6 years of age and older carrying the G551D mutation. PMID:25441013

  20. MEASUREMENT OF EXHALED BREATH AND VENOUS BLOOD TO DEVELOP A PHYSIOLOGICALLY BASED PHARMACOKINETIC MODEL FOR HUMAN EXPOSURE TO METHYL TERTIARY-BUTYL ETHER AND THE PRODUCTION OF THE BIOMARKER TERTIARY-BUTYL ALCOHOL

    EPA Science Inventory

    Methyl tertiary-butyl ether (MTBE) is a common fuel additive used to increase the availability of oxygen in gasoline to reduce winter-time carbon monoxide emissions from automobiles. Also, MTBE boosts gasoline "octane" rating and, as such, allows reduction of benzene...

  1. (1-Butyl-4-methyl-pyridinium)[Cu(SCN)2]: a coordination polymer and ionic liquid.

    PubMed

    Spielberg, Eike T; Edengeiser, Eugen; Mallick, Bert; Havenith, Martina; Mudring, Anja-Verena

    2014-04-25

    The compound (C4C1py)[Cu(SCN)2], (C4C1py = 1-Butyl-4-methyl-pyridinium), which can be obtained from CuSCN and the ionic liquid (C4C1py)(SCN), turns out to be a new organic-inorganic hybrid material as it qualifies both, as a coordination polymer and an ionic liquid. It features linked [Cu(SCN)2](-) units, in which the thiocyanates bridge the copper ions in a ?1,3-fashion. The resulting one-dimensional chains run along the a?axis, separated by the C4C1py counterions. Powder X-ray diffraction not only confirms the single-crystal X-ray structure solution but proves the reformation of the coordination polymer from an isotropic melt. However, the materials shows a complex thermal behavior often encountered for ionic liquids such as a strong tendency to form a supercooled melt. At a relatively high cooling rate, glass formation is observed. When heating this melt in differential scanning calorimetry (DSC) and temperature-dependent polarizing optical microscopy (POM), investigations reveal the existence of a less thermodynamically stable crystalline polymorph. Raman measurements conducted at 10 and 100?°C point towards the formation of polyanionic chain fragments in the melt. Solid-state UV/Vis spectroscopy shows a broad absorption band around 18,870?cm(-1) (530?nm) and another strong one below 20,000?cm(-1) (<500?nm). The latter is attributed to the d(Cu(I))??*(SCN)-MLCT (metal-to-ligand charge transfer) transition within the coordination polymer yielding an energy gap of 2.4?eV. At room temperature and upon irradiation with UV light, the material shows a weak fluorescence band at 15,870?cm(-1) (630?nm) with a quantum efficiency of 0.90(2)?% and a lifetime of 131(2)?ns. Upon lowering the temperature, the luminescence intensity strongly increases. Simultaneously, the band around 450?nm in the excitation spectrum decreases. PMID:24644064

  2. Protective effects of germinated and fermented soybean extract against tert-butyl hydroperoxide-induced hepatotoxicity in HepG2 cells and in rats.

    PubMed

    Kim, Eun Young; Hong, Ki-Bae; Suh, Hyung Joo; Choi, Hyeon-Son

    2015-11-01

    The aim of the current study is to investigate the antioxidant and hepatoprotective effects of germinated and fermented soybean extract (GFSE) on tert-butyl hydroperoxide (t-BHP)-induced oxidative stress in HepG2 cells and in the rat liver. High performance liquid chromatography (HPLC) analysis showed that genistin (3.40 ± 0.14 ?g mg(-1)) was the most abundant isoflavone in the GFSE. Coumestrol (1.00 ± 0.04 ?g mg(-1)), daidzin (0.78 ± 0.14 ?g mg(-1)), genistein (0.68 ± 0.05 ?g mg(-1)), glycitin (0.54 ± 0.02 ?g mg(-1)), glycitein (0.41 ± 0.02 ?g mg(-1)), and daidzein (0.02 ± 0.0 g mg(-1)) are also contained in decreasing order of content. GFSE significantly inhibited t-BHP-induced reactive oxygen species (ROS) production in HepG2 cells. This GFSE-induced ROS reduction was associated with the down-regulation of nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4), a pro-oxidant enzyme, and the up-regulation of the mRNA levels of antioxidant enzymes, including catalase, superoxide dismutase (SOD), glutathione reductase (GR), and glutathione peroxidase (Gpx) in the rat liver. In addition, increased levels of antioxidant enzyme mRNAs correlated with the enhanced enzymatic activities of SOD, catalase, and glutathione-S-transferase (GST). The antioxidant effect of GFSE was supported by the reduction in the levels of malondialdehyde (MDA), a hydroperoxide, and the serum levels of lactate dehydrogenase (LDH), a biomarker of cell damage, were also lowered by GFSE. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST), which are clinical biomarkers of liver function, were shown to be improved with GFSE administration. The effects of GFSE were attributable to an improvement in liver tissue morphology. Taken together, GFSE protected the liver from t-BHP-induced oxidative stress by regulating ROS-related enzymes. Our results suggest that GFSE might be a hepatoprotective source against oxidative stress. PMID:26299642

  3. Slow-binding inhibition of human prostaglandin endoperoxide synthase-2 with darbufelone, an isoform-selective antiinflammatory di-tert-butyl phenol.

    PubMed

    Johnson, A R; Marletta, M A; Dyer, R D

    2001-06-26

    The antiinflammatory agent darbufelone, ((Z)-5-[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl] methylene]-2-imino-4-thiazolidinone, methanesulfonate salt), was discovered as a dual inhibitor of cellular prostaglandin and leukotriene production. To study the mechanism of action of this drug, we expressed human prostaglandin endoperoxide synthase-1 (PGHS-1) and PGHS-2 and purified the recombinant enzymes using buffers that contain octylglucoside. In cyclooxygenase assays following a 15-min incubation of enzyme with inhibitor, darbufelone potently inhibits PGHS-2 (IC(50) = 0.19 microM) but is much less potent with PGHS-1 (IC(50) = 20 microM). Interestingly, when the assay buffer contains traces of Tween 20 (0.0001%), darbufelone appears inactive with PGHS-2 due to a detergent interaction that is detectable by absorption spectroscopy. We therefore used octylglucoside, which does not affect darbufelone in this way, in place of Tween 20 in our PGHS buffers. Inhibition of PGHS-2 with darbufelone is time dependent: with no preincubation, darbufelone is a weak inhibitor (IC(50) = 14 microM), but after a 30-min incubation it is 20-fold more potent. Plots of PGHS-2 activity vs preincubation time at various darbufelone concentrations reach a plateau. This finding is inconsistent with irreversible or one-step slow-binding inhibition. A two-step slow-binding inhibition model is proposed in which the E.I complex (K(i) = 6.2 +/- 1.9 to 14 +/- 1 microM) slowly transforms (k(5) = 0.015-0.030 s(-)(1)) to a tightly bound E.I form with K(i) = 0.63 +/- 0.07 microM and k(6) = 0.0034 s(-)(1). In steady-state kinetics inhibition experiments performed with no preincubation, we find that darbufelone is a noncompetitive inhibitor of PGHS-2 (K(i) = 10 +/- 5 microM). Darbufelone quenches the fluorescence of PGHS-2 at 325 nm (lambda(ex) = 280 nm) with K(d) = 0.98 +/- 0.03 microM. The PGHS substrate, arachidonate, and various cyclooxygenase inhibitors do not alter this binding affinity of darbufelone but a structural analogue of darbufelone competes directly for binding to PGHS-2. Di-tert-butyl phenols such as darbufelone may inhibit PGHS-2 by exploiting a previously unrecognized binding site on the enzyme. PMID:11412128

  4. Isolation and characterization of 4-tert-butylphenol-utilizing Sphingobium fuliginis strains from Phragmites australis rhizosphere sediment.

    PubMed

    Toyama, Tadashi; Momotani, Naonori; Ogata, Yuka; Miyamori, Yuji; Inoue, Daisuke; Sei, Kazunari; Mori, Kazuhiro; Kikuchi, Shintaro; Ike, Michihiko

    2010-10-01

    We isolated three Sphingobium fuliginis strains from Phragmites australis rhizosphere sediment that were capable of utilizing 4-tert-butylphenol as a sole carbon and energy source. These strains are the first 4-tert-butylphenol-utilizing bacteria. The strain designated TIK-1 completely degraded 1.0 mM 4-tert-butylphenol in basal salts medium within 12 h, with concomitant cell growth. We identified 4-tert-butylcatechol and 3,3-dimethyl-2-butanone as internal metabolites by gas chromatography-mass spectrometry. When 3-fluorocatechol was used as an inactivator of meta-cleavage enzymes, strain TIK-1 could not degrade 4-tert-butylcatechol and 3,3-dimethyl-2-butanone was not detected. We concluded that metabolism of 4-tert-butylphenol by strain TIK-1 is initiated by hydroxylation to 4-tert-butylcatechol, followed by a meta-cleavage pathway. Growth experiments with 20 other alkylphenols showed that 4-isopropylphenol, 4-sec-butylphenol, and 4-tert-pentylphenol, which have alkyl side chains of three to five carbon atoms with ?-quaternary or ?-tertiary carbons, supported cell growth but that 4-n-alkylphenols, 4-tert-octylphenol, technical nonylphenol, 2-alkylphenols, and 3-alkylphenols did not. The rate of growth on 4-tert-butylphenol was much higher than that of growth on the other alkylphenols. Degradation experiments with various alkylphenols showed that strain TIK-1 cells grown on 4-tert-butylphenol could degrade 4-alkylphenols with variously sized and branched side chains (ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-heptyl, n-octyl, tert-octyl, n-nonyl, and branched nonyl) via a meta-cleavage pathway but not 2- or 3-alkylphenols. Along with the degradation of these alkylphenols, we detected methyl alkyl ketones that retained the structure of the original alkyl side chains. Strain TIK-1 may be useful in the bioremediation of environments polluted by 4-tert-butylphenol and various other 4-alkylphenols. PMID:20802076

  5. SENSORY, SYMPTOMATIC, INFLAMMATORY, AND OCULAR RESPONSES TO AND THE METABOLISM OF METHYL TERTIARY BUTYL ETHER IN A CONTROLLED HUMAN EXPOSURE EXPERIMENT

    EPA Science Inventory

    In response to elevated ambient carbon monoxide (CO) due to incomplete combustion of automotive fuels, the Clear Air Act mandates that CO reduction be obtained by adding oxygenates to the fuel (oxyfuel) in areas of non-attainment. In 1992 the addition of methyl tertiary butyl eth...

  6. PRODUCTS OF THE GAS-PHASE REACTIONS OF THE OH RADICAL WITH N-BUTYL METHYL ETHER AND 2-ISOPROPOXYETHANOL: REACTIONS OF ROC(O)< RADICALS. (R825252)

    EPA Science Inventory

    The products of the gas-phase reactions of the OH radical with n-butyl methyl ether and 2-isopropoxyethanol in the presence of NO have been investigated at 298 ? 2 K and 740 Torr total pressure of air by gas chromatography and in situ atmospheric pressure ionization...

  7. Tetrabutylammonium iodide catalyzed allylic sulfonylation of ?-methyl styrene derivatives with sulfonylhydrazides.

    PubMed

    Li, Xiaoqing; Xu, Xiangsheng; Zhou, Can

    2012-12-28

    Sulfonyl radicals generated from sulfonylhydrazides by the Bu(4)NI-tert-butyl hydroperoxide (TBHP) catalysis system underwent addition to a variety of ?-methyl styrene derivatives to give the corresponding allylic sulfones. This selective allylic sulfonylation is metal-free, operationally simple, and environmentally friendly. PMID:23147597

  8. Uterotrophic assay, Hershberger assay, and subacute oral toxicity study of 4,4'-butylidenebis(2-tert-butyl-5-methylphenol) and 3-(dibutylamino)phenol, based on the OECD draft protocols.

    PubMed

    Yamasaki, Kanji; Miyata, Katusi; Shiraishi, Keiji; Muroi, Takako; Higashihara, Nobuhiko; Oshima, Hiroshi; Minobe, Yasushi

    2008-05-01

    We performed a uterotrophic assay, the Hershberger assay, and a 28-day repeated-dose toxicity study [enhanced Organization for Economic Co-operation and Development (OECD) test guideline No. 407] of 4,4'-butylidenebis(2-tert-butyl-5-methylphenol) and 3-(dibutylamino)phenol, based on the OECD draft protocols. In the uterotrophic assay of 4,4'-butylidenebis(2-tert-butyl-5-methylphenol), female SD rats were subcutaneously injected with the chemical at doses of 0, 100, 300, and 1,000 mg/kg on each of 3 days from postnatal day 20 to day 22, and no changes were observed. In the Hershberger assay of 4,4'-butylidenebis(2-tert-butyl-5-methylphenol), the test chemical was orally administered to castrated male SD rats at doses of 0, 50, 200, and 1,000 mg/kg/day for ten consecutive days beginning on postnatal day 56, and no changes were observed. When this chemical was orally administered at doses 0, 5, 25, and 125 mg/kg/day for at least 28 days in the subacute oral toxicity study, an increase in thyroid weight was observed in the female rats in the 125 mg/kg group, an increase in serum thyroid-stimulating hormone (TSH) values in the male and female rats in the 125 mg/kg group, and a decrease in serum T3 and T4 values in the male rats in the 125 mg/kg group, and thyroid follicular epithelial cell hypertrophy was observed in some of the female rats in the 125 mg/kg group. These findings were concluded to be the result of endocrine-mediated effects of the chemical on thyroid function. In addition, increased liver weight, abnormal histological findings in the liver, and abnormal biochemical parameters related to liver function were observed in male and/or female rats in 5 mg/kg group and higher dose groups. The no-observed-effect level for 4,4'-butylidenebis(2-tert-butyl-5-methylphenol) was concluded to be <5 mg/kg/day. In the uterotrophic assay of 3-(dibutylamino)phenol, female SD rats were subcutaneously injected with the chemical at doses of 0, 100, 300, and 1,000 mg/kg on each of 3 days from postnatal day 20 to day 22, and no changes were observed. In the Hershberger assay of 3-(dibutylamino)phenol, the test chemical was orally administered at doses of 0, 50, 200, and 400 mg/kg/day to castrated male SD rats for ten consecutive days beginning on postnatal day 56, and no changes were observed. On the other hand, when this test chemical was orally administered at doses 0, 30, 100, and 300 mg/kg/day for at least 28 days in the subacute oral toxicity study, thyroid weight increased in the male rats in the 300 mg/kg group, thyroid follicular epithelial cell hypertrophy was observed in a small number of male rats in the 300 mg/kg group, serum T3-values decreased in the female rats in the 300 mg/kg group, and a tendency for TSH-values to increase was observed in the male and female rats in the 300 mg/kg group. Therefore, 3-(dibutylamino)phenol was also concluded to have slight anti-thyroid acting effects as the endocrine-mediated effects. On the other hand, increased hemosiderin deposition in the spleen, increased spleen weight, hematological abnormalities, and squamous epithelial hyperplasia of the forestomach were detected in male and/or female rats in the 100 and/or 300 mg/kg groups, and thus the no-observed-effect level for 3-(dibutylamino)phenol was concluded to be 30 mg/kg/day. PMID:17924095

  9. Properties of 2,6-di-tert.-butyl-4-(2,5-diphenyl-3,4-dihydro-2H-pyrazol-3-yl)-phenol as hole-transport material for life extension of organic light emitting diodes

    NASA Astrophysics Data System (ADS)

    Cherpak, V.; Stakhira, P.; Khomyak, S.; Volynyuk, D.; Hotra, Z.; Voznyak, L.; Dovbeshko, G.; Fesenko, O.; Sorokin, V.; Rybalochka, A.; Oliynyk, O.

    2011-09-01

    We studied structural and optical properties of 5' replaced pyrazoline by hindered phenol 2,6-di-tert.-butyl-4-(2,5-diphenyl-3,4-dihydro-2H-pyrazol-3-yl)-phenol (HPhP) films for application in organic light-emitting diode (OLED) as a hole transport layer (HTL). Analysis of impedance and current-voltage characteristics of ITO/HPhP/Al structure has shown that the current is limited by a space charged region with exponential distribution of traps near Fermi level. Characteristics of electroluminescence structure ITO/HPhP/Alq 3/poly(ethylene glycol) dimethyl ether/Al was studied and analyzed. We performed the comparative analysis of luminescence time decay in two types of electroluminescent devices with HTL from pyrazolines derivative with hindered phenol and without it. We showed that hindered phenol in HTL slows down the degradation processes in OLED.

  10. Computational Study of the Degradation and Removal of Methyl Tert-Butyl Ether (MTBE) from Aqueous Solutions.

    E-print Network

    Gosselin, Louis A.

    Oxidation Processes (AOP) may fill this gap, providing with a suitable water treatment process (Cooper et al., 2009). AOPs use free-radicals to produce a chain of organic reactions that sever organic molecules

  11. Identifying the usage patterns of methyl tert-butyl ether (MTBE) and other oxygenates in gasoline using gasoline surveys

    USGS Publications Warehouse

    Moran, M.J.; Clawges, R.M.; Zogorski, J.S.

    2000-01-01

    Data on the volumes of oxygenates and other compounds in gasoline are available from several sources collectively referred as gasoline surveys. The gasoline surveys provide the most definitive knowledge of which oxygenate, if any, and what volumes of that oxygenate are being used in various areas of the country. This information is important in water-quality assessments for relating the detection of MTBE in water to patterns of usage of MTBE in gasoline. General information on three surveys that have been conducted by the National Institute for Petroleum and Energy Research, the Motor Vehicle Manufacturers Association, and the EPA was presented. The samples were tested for physical properties and constituents including octane number, specific gravity, and volumes of olefins, aromatics, benzene, alcohols, and various ether oxygenates. The data in each survey had its own utility based on the type of assessment that is undertaken. Quality Assessment (NAWQA) Program. Using NAWQA data, the percent occurrence of MTBE in ground water in metropolitan areas that use substantial amounts of MTBE (> 5% by vol) was ??? 21%, compared to ??? 2% in areas that do not use substantial amounts of MTBE (< 5% by vol). When several other factors are considered in a logistic regression model including MTBE usage in RFG or OXY gasoline areas (??? 3% by vol) as a factor, a 4-6 fold increase in the detection frequency of MTBE in ground water was found when compared to areas that do not use MTBE or use it only for octane enhancement (< 3% by vol).

  12. EXPERIMENTAL MEASUREMENT OF THE RATE OF METHYL TERT-BUTYL ETHER HYDROLYSIS IN SUB- AND SUPERCRITICAL WATER. (R826738)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  13. Cobalt(II)-mediated synthesis of 2,6-bis[5,7-di-tert-butyl-1,3-benzoxazol-2-yl]-pyridine: Structural analysis and coordination behavior

    NASA Astrophysics Data System (ADS)

    Garza-Ortíz, Ariadna; Martínez, Pablo A.; Duarte-Hernández, Angelica M.; Mijangos, Edgar; Flores-Álamo, Marcos; Pérez-Casas, Carol; Camacho-Camacho, Carlos; Contreras, Rosalinda; Flores-Parra, Angelina; Reedijk, Jan; Barba-Behrens, Norah

    2013-01-01

    The oxidative cyclization of 2,6-bis[2,4-di-tert-butyl-6-(methylidenylamino)phenol]-pyridine (L1) in acetonitrile, through the cobalt(II) coordination compound of L1, has resulted in a convenient route for the preparation of 2,6-bis[5,7-di-tert-butyl-1,3-benzoxazol-2-yl]-pyridine (L3). The X-ray diffraction analysis of L3 shows a planar molecule, with the oxygen atoms from the benzoxazole rings oriented to the pyridine nitrogen atom (conformer L3a). Ab initio calculations indicate that from the three possible planar conformers of L3, the more stable is L3a. The solid state conformation of the free ligand L3 and the relative energy of the three calculated conformers indicated stabilizing N ? O interactions. Calculations of the protonated derivative of L3, compound 7, indicated that the most stable conformer has the benzoxazole nitrogen atoms pointing to the protonated pyridine NH (7c). The X-ray crystal analysis of ligand L3 coordinated to cobalt(II) nitrate, compound 4 is presented and conformer L3c is found in this compound. Two acid:base complexes [Zn(NO3)2(H2O)2][L3c]2, compound 5, and [NEt2H2Cl][L3c], compound 6, have also been investigated. Complex 5 crystallized and its X-ray diffraction analysis is reported, whereas compound 6 was studied in solution by NMR, mass spectrometry and ab initio calculations. Both complexes show that conformer L3c can form stable hydrogen bonding associations, with molecules having the motif YH2 (Y = N or O), that are of interest for building up supramolecular associations.

  14. Crystal structure and absolute configuration of (3S,4aS,8aS)-N-tert-butyl-2-[(S)-3-(2-chloro-4-nitro­benzamido)-2-hy­droxy­prop­yl]deca­hydro­isoquinoline-3-carboxamide and (3S,4aS,8aS)-N-tert-butyl-2-{(S)-2-[(S)-1-(2-chloro-4-nitro­benzoyl)pyrrolidin-2-yl]-2-hy­droxy­eth­yl}deca­hydro­iso­quinoline-3-carboxamide

    PubMed Central

    Maxson, Tucker; Bertke, Jeffery A.; Gray, Danielle L.; Mitchell, Douglas A.

    2015-01-01

    The crystal structure and absolute configuration of the two new title nelfinavir analogs, C24H35ClN4O5, (I), and C27H39ClN4O5, (II), have been determined. Each of these mol­ecules exhibits a number of disordered moieties. There are intra­molecular N—H?O hydrogen bonds in both (I) and (II). In (I) it involves the two carboxamide groups, while in (II) it involves the N-tert-butyl carboxamide group and the 2-hydroxyl O atom. The inter­molecular hydrogen bonding in (I) (O—H?O and N—H?O) leads to two-dimensional sheets that extend parallel to the ac plane. The inter­molecular hydrogen bonding in (II) (O—H?O) leads to chains that extend parallel to the a axis. PMID:26594520

  15. The interface between HOPG and 1-butyl-3-methyl-imidazolium hexafluorophosphate.

    PubMed

    Müller, C; Németh, K; Vesztergom, S; Pajkossy, T; Jacob, T

    2016-01-14

    The interface between highly oriented pyrolytic graphite (HOPG) and 1-butyl-3-metyl-imidazolium hexafluorophosphate (BMIPF6) has been studied using cyclic voltammetry, electrochemical impedance spectroscopy, immersion charge measurements and in situ scanning tunneling microscopy (in situ STM). The results are compared with those obtained with Au(100) in BMIPF6 (Phys. Chem. Chem. Phys., 2011, 13, 11627). The main result is that the high frequency capacitance spectra on the two systems are similar to each other, however at low frequencies some slow interfacial processes cause the appearance of a second capacitance arc on Au(100), which is absent for HOPG. The slow processes are attributed to the rearrangement of the Au surface structure and to the formation of ionic liquid adlayers - these are visualized by in situ STM. PMID:26647859

  16. Dynamics of Back Electron Transfer in Dye-Sensitized Solar Cells Featuring 4-tert-Butyl-Pyridine and Atomic-Layer-Deposited Alumina

    E-print Network

    -Butyl-Pyridine and Atomic-Layer-Deposited Alumina as Surface Modifiers Michael J. Katz, Michael J. DeVries Vermeer,, Omar K modified with atomic-layered-deposited (ALD) coatings of Al2O3 and/or with the surface-adsorbing additive 4

  17. IDENTIFICATION AND DETERMINATION OF TERT-ALKLYPHENOLS IN CARP FROM THE TRENTON CHANNEL OF THE DETROIT RIVER, MI

    EPA Science Inventory

    Whole carp from the Detroit River were analyzed by gas chromatographic mass spectrometry. even tertiary alkyl phenols (tert-pentylphenols, tert-butyl-tert-pentylphenols, a di-tert-pentylphenol and a tri-tert-pentylphenol) and eight chlorinated derivatives of these compounds were ...

  18. The mechanism of formation of stable radical pairs by photolysis of 2,6-di-tert-butylbenzoquinone diazide in crystals of 2,6-di-tert-butyl-4-methylphenol

    NASA Astrophysics Data System (ADS)

    Lazarev, G. G.; Kuskov, V. L.; Lebedev, Ya. S.; Rieker, A.

    1991-07-01

    The nature of radical pairs obtained by irradiation of single crystals of sterically hindered O-deuterated phenols containing 10 -3 M 2,6-di-tert-butylquinone diazide has been studied by electron-polarization-resonance (EPR) spectroscopy. A possible channel for the hydrogen-atom transfer was derived on the basis of calculated D and E values from the EPR spectra of the observed radical pairs. The thermal coefficients for the linear expansion of the crystal of deuterated phenol and diazide were measured.

  19. Synthesis and characterization of poly(methyl methacrylate-butyl acrylate)/nano-titanium oxide composite particles.

    PubMed

    Guo, Gang; Yu, Jie; Luo, Zhu; Zhou, LiangXue; Liang, Hang; Luo, Feng; Qian, ZhiYong

    2011-06-01

    Poly(methyl methacrylate-butyl acrylate) [P(MMA-BA)]/nanosized titanium oxide (nano-TiO2) composite particles were prepared via insitu emulsion polymerization of MMA and BA in presence of nano-TiO2 particles. Before polymerization, the nano-TiO2 particles were modified by coupling agent. The structure and thermal properties of the obtained P(MMA-BA)/nano-TiO2 composite particles were characterized by Fourier transform infrared spectra (FTIR), wide-angle X-ray diffraction (WAXD) and thermogravimetric analysis (TGA). The results showed that there are covalent bond bindings between P(MMA-BA) and nano-TiO2 particles, meaning that P(MMA-BA) and nano-TiO2 particles were not simply blended or mixed up and that there is a strong interaction between P(MMA-BA) and nano-TiO2 particles. TGA and DSC measurements indicated an enhancement of thermal stability. Transmission electron microscopy (TEM) results showed that P(MMA-BA) enhanced the dispersibility of nano-TiO2 particles. The dispersion stabilization of modified nano-TiO2 particles in aqueous system was significantly improved due to the introduction of grafted polymer on the surface of nano-particles. PMID:21770123

  20. The impact of groundwater quality on the removal of methyl tertiary-butyl ether (MTBE) using advanced oxidation technology.

    PubMed

    Tawabini, B; Fayad, N; Morsy, M

    2009-01-01

    In this study, the removal of methyl tertiary-butyl ether (MTBE) from contaminated groundwater using advanced oxidation technology was investigated. The UV/H(2)O(2) treatment process was applied to remove MTBE from two Saudi groundwater sources that have different quality characteristics with regard to their contents of inorganic species such as chloride, bromide, sulfates and alkalinity. MTBE was spiked into water samples collected from the two sources to a concentration level of about 250 microg/L. A 500 mL bench-scale forced-liquid circulation photoreactor was used to conduct the experiments. Two different UV lamps were utilized: 15 Watt low pressure (LP) and 150 Watt medium pressure (MP). Results of the study showed that the UV/H(2)O(2) process removed more than 90% of MTBE in 20 minutes when the MP lamp was used at an MTBE/H(2)O(2) molar ratio of 1:200. The results also showed that groundwater sources with higher levels of radical scavengers such as alkalinity, bromide, nitrate and sulfate showed lower rate of MTBE removal. PMID:19844063

  1. Construction of wettability gradient surface on copper substrate by controlled hydrolysis of poly(methyl methacrylate-butyl acrylate) films

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Cheng, Jiang; Yang, Zhuo-ru

    2014-10-01

    We report a gradient wettability surface on copper slide prepared by a simple controlled ester group hydrolysis procedure of poly(methyl methacrylate-butyl acrylate) [P (MMA-BA)] films coated on the copper substrate. In the method, sodium hydroxide solutions are selected to prepare surface gradient wettability on P (MMA-BA) films. The P (MMA-BA) copolymers with different MMA contents are first synthesized by a conventional free atom radical solution polymerization method. The transfer of surface chemical composition from the ester group to acid salt is achieved by hydrolysis in NaOH solution. The effects of different concentrations of NaOH solution and reaction times on the physicochemical properties of the resulting surfaces are studied. The field-emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) results show that the varying concentration along the substrate length is only attributed to the hydrolysis reaction of ester groups. The hydrolysis causes insignificant change on the morphology of the original film on the copper substrate. In addition, it is found that the MMA copolymer content has a significant influence on the concentration of ester groups on the outermost surface and thus important for forming the slope gradients.

  2. Seasonal and daily variations in concentrations of methyl-tertiary-butyl ether (MTBE) at Cranberry Lake, New Jersey

    USGS Publications Warehouse

    Toran, L.; Lipka, C.; Baehr, A.; Reilly, T.; Baker, R.

    2003-01-01

    Methyl-tertiary-butyl ether (MTBE), an additive used to oxygenate gasoline, has been detected in lakes in northwestern New Jersey. This occurrence has been attributed to the use of gasoline-powered watercraft. This paper documents and explains both seasonal and daily variations in MTBE concentrations at Cranberry Lake. During a recent boating season (late April to September 1999), concentrations of MTBE typically exceeded 20??g/L. MTBE concentrations varied daily from 12 to 24??g/L over a 2-week period that included the Labor Day holiday. Concentrations were highest on weekends when there is more boat traffic, which had an immediate effect on MTBE mass throughout the lake. MTBE concentrations decreased to about 2??g/L shortly after the end of the summer recreational season. The loss of MTBE can be accounted for by volatilization, with a half-life on the order of 10 days. The volatilization rate was modeled with the daily decrease in MTBE then the modeled rate was validated using the data from the seasonal decline. ?? 2003 Elsevier Science Ltd. All rights reserved.

  3. Supporting Information Surface residence and uptake of methyl chloride and methyl alcohol at the

    E-print Network

    1 Supporting Information Surface residence and uptake of methyl chloride and methyl alcohol spectra from flow experiments over water of methyl alcohol, methyl chloride, butyl alcohol, butyl chloride(a.u) 295029002850 Incident Infrared (cm -1 ) 0.6 0.4 0.2 0.0 Methyl alcohol Methyl chloride Butyl alcohol Butyl

  4. 2,6-Di-tert-butyl-4-(2'-thenoyl)phenol(R-830): a novel nonsteroidal anti-inflammatory agent with antioxidant properties.

    PubMed

    Moore, G G; Swingle, K F

    1982-12-01

    R-830, a di-tert-butylphenol, has been shown to be anti-inflammatory in a number of animal models. These include conventional systems such as carrageenan-induced edema and adjuvant arthritis of the rat and ultraviolet-induced erythema in the guinea pig in which the acidic nonsteroidal anti-inflammatory drugs (e.g., indomethacin) are effective. The anti-inflammatory activity of R-830 has also been demonstrated in other models (e.g., graft vs. host reaction and reversed passive cutaneous Arthus reaction in the rat, contact sensitivity in the mouse) in which the acidic nonsteroidal drugs are not effective. In vitro, R-830 inhibits guinea pig lung lipoxygenase and bovine seminal vesicle cyclo-oxygenase. The antioxidant properties of R-830 were demonstrated in two in vitro systems. We speculate that the antioxidant activity of this molecule might be related to its unusual profile of pharmacological activity. PMID:6819772

  5. Solid state {sup 1}H spin-lattice relaxation and isolated-molecule and cluster electronic structure calculations in organic molecular solids: The relationship between structure and methyl group and t-butyl group rotation

    SciTech Connect

    Wang, Xianlong E-mail: pbeckman@brynmawr.edu; Mallory, Frank B.; Mallory, Clelia W.; Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323 ; Odhner, Hosanna R.; Beckmann, Peter A. E-mail: pbeckman@brynmawr.edu

    2014-05-21

    We report ab initio density functional theory electronic structure calculations of rotational barriers for t-butyl groups and their constituent methyl groups both in the isolated molecules and in central molecules in clusters built from the X-ray structure in four t-butyl aromatic compounds. The X-ray structures have been reported previously. We also report and interpret the temperature dependence of the solid state {sup 1}H nuclear magnetic resonance spin-lattice relaxation rate at 8.50, 22.5, and 53.0 MHz in one of the four compounds. Such experiments for the other three have been reported previously. We compare the computed barriers for methyl group and t-butyl group rotation in a central target molecule in the cluster with the activation energies determined from fitting the {sup 1}H NMR spin-lattice relaxation data. We formulate a dynamical model for the superposition of t-butyl group rotation and the rotation of the t-butyl group's constituent methyl groups. The four compounds are 2,7-di-t-butylpyrene, 1,4-di-t-butylbenzene, 2,6-di-t-butylnaphthalene, and 3-t-butylchrysene. We comment on the unusual ground state orientation of the t-butyl groups in the crystal of the pyrene and we comment on the unusually high rotational barrier of these t-butyl groups.

  6. Crystal structure of bis­(?5-cyclo­penta­dien­yl)(1,4-di-tert-butyl­buta-1-en-3-yn-1-yl)zirconium(IV) ?2-hydroxido-bis­[tris(penta­fluoro­phen­yl)borate

    PubMed Central

    Burlakov, Vladimir V.; Spannenberg, Anke; Arndt, Perdita; Rosenthal, Uwe

    2015-01-01

    Alkyl zirconocene cations have been of considerable inter­est as reactive species in many polymerization processes. In the crystal structure of the title compound, [Zr(C12H19)(C5H5)2](C36HB2F30O), the [Zr(C5H5)2((t-Bu)C=C(H)—C2(t-Bu))]+ cation displays a buta-1-en-3-yne ligand side-on coordinated to a typical bent zirconocene [centroid(cp)—Zr—centroid(cp) = 131.4?(3)°, Zr—C(buta-1-en-3-yne) = 2.255?(3), 2.597?(3) and 2.452?(2)?Å]. In the [HO(B(C6F5)3)2]? anion, intra­molecular O—H?F hydrogen bonds are observed. One tert-butyl group in the complex cation is disordered over two sets of sites with occupancies 0.701(4):0.299(4). PMID:25844214

  7. Differential modulation by the GABAB receptor allosteric potentiator 2,6-di-tert-butyl-4-(3-hydroxy-2,2-dimethylpropyl)-phenol (CGP7930) of synaptic transmission in the rat hippocampal CA1 area.

    PubMed

    Chen, Ying; Menendez-Roche, Nicole; Sher, Emanuele

    2006-06-01

    The recently discovered GABAB receptor-positive allosteric modulators enhanced the potency and efficacy of GABAB receptor agonists in in vitro experiments. These GABAB modulators also attenuated reward and anxiety in behavioral experiments without causing the untoward side effects associated with GABAB receptor activation by agonist administration and hence exhibited potential therapeutic utility. However, the underlying molecular mechanisms enabling the GABAB allosteric modulators to dissociate from the GABAB agonistic side effects remain elusive. To address this question, we have examined the effects of a typical GABAB modulator, 2,6-di-tert-butyl-4-(3-hydroxy-2,2-dimethylpropyl)-phenol (CGP7930), on GABAB receptor-mediated modulations of both the excitatory and the delayed inhibitory components of hippocampal CA1 synaptic transmission. Using baclofen as an agonist and a multielectrode recording system, we recorded GABAB receptor-mediated modulations of both the field excitatory postsynaptic potentials and the population spikes simultaneously, as well as the paired-pulse inhibition of the population spike. We found that CGP7930 selectively enhanced the baclofen-induced modulation of synaptic inhibition without having any significant effects on the synaptic excitation. Our experiments have therefore revealed a pathway-selective differential modulation of synaptic transmission by CGP7930. This finding provides a synaptic mechanism to support the hypothesis that GABAB potentiators may be a better therapeutic alternative than GABAB agonists for central nervous system disorders. PMID:16507713

  8. Spectroscopic (FT-IR, FT-Raman), first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis of 5-tert-Butyl-6-chloro-N-[(4-(trifluoromethyl)phenyl]pyrazine-2-carboxamide.

    PubMed

    Bhagyasree, J B; Varghese, Hema Tresa; Panicker, C Yohannan; Van Alsenoy, Christian; Al-Saadi, Abdulaziz A; Dolezal, Martin; Samuel, Jadu

    2015-02-25

    The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 5-tert-Butyl-6-chloro-N-[(4-(trifluoromethyl)phenyl]pyrazine-2-carboxamide have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of normal modes of vibrations was done using GAR2PED program. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. From the NBO analysis it is evident that the increased electron density at the nitrogen, carbon atoms leads to the elongation of respective bond length and a lowering of the corresponding stretching wave number. The calculated geometrical parameters are in agreement with that of similar derivatives. The calculated first hyperpolarizability is high and the calculated data suggest an extended ?-electron delocalization over the pyrazine ring and carboxamide moiety which is responsible for the nonlinearity of the molecule. PMID:25218229

  9. Simultaneous liquid-liquid extraction of dibenzyl disulfide, 2,6-di-tert-butyl-p-cresol, and 1,2,3-benzotriazole from power transformer oil prior to GC and HPLC determination.

    PubMed

    Jaber, Abdul Muttaleb Yousef; Mehanna, Nemr Ahmed; Abulkibash, Abdalla Mahmoud

    2012-03-01

    2,6-Di-tert-butyl-p-cresol (DBPC), dibenzyl disulfide (DBDS), and 1,2,3-benzotriazole (BTA) are additives that may be found concomitantly in the oil matrix of power transformer. DBPC and DBDS act as antioxidants while, BTA is a corrosion inhibitor that protects copper conductors inside the transformer unit from corrosion. A powerful analytical method is, therefore, required to determine these additives at trace levels in the transformer oil. This work describes a unique single liquid-liquid extraction pretreatment step prior to the determination of the components by gas chromatography (GC) and high-performance liquid chromatography (HPLC) techniques. The optimum volume ratio used in the pretreatment step was determined as 5:2:5 for mineral oil/n-hexane/acetonitrile, respectively. Relatively, the method is simple and quick with a minimal use of solvents. Analytical results indicate that the method is relatively sensitive, accurate, and precise for each of the three components in fresh and used mineral oil. The calibration curves for the three components demonstrate a significant increase in sensitivities. Detection limits found were, 100 mg L(-1) (0.01% w/v), 0.80 mg L(-1) , and 2.04 mg L(-1) for DBPC, DBDS, and BTA, respectively. The Student's t values determined at 95% confidence level indicate that there is no significant difference between the experimental means obtained by this method and the standard method for each component. PMID:22311820

  10. Safety assessment for octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate (CAS Reg. No. 2082-79-3) from use in food contact applications.

    PubMed

    Neal-Kluever, April P; Bailey, Allan B; Hatwell, Karen R

    2015-12-01

    Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (CAS Reg. No. 2082-79-3), currently marketed as Irganox 1076 (I-76), is a sterically hindered phenolic antioxidant used in a variety of organic substrates, including those used in the manufacture of food contact articles. In 2012, the US Food and Drug Administration (USFDA), Office of Food Additive Safety (OFAS), initiated a post-market re-evaluation of the food contact applications of I-76. This project aimed to ensure that current dietary exposures from the use of I-76 in food contact articles are accurately captured and the safety assessment considered all relevant and available toxicological information. To accomplish these aims, the USFDA reviewed the available toxicological studies and chemistry information on food contact applications of I-76. Based on this in-depth analysis, a NOAEL of 64 mg/kg-bw/d (female rats) from a chronic rat study and a cumulative estimated dietary intake (CEDI) of 4.5 mg/p/d, was used to calculate a margin of exposure (MOE) of ?850. We concluded that the previous and current exposure levels provide an adequate margin of safety (MOS) and remain protective of human health for the regulated uses. PMID:26482640

  11. Chronic Carcinogenicity Study of Gasoline Vapor Condensate (GVC) and GVC Containing Methyl Tertiary-Butyl Ether in F344 Rats

    PubMed Central

    Benson, Janet M.; Gigliotti, Andrew P.; March, Thomas H.; Barr, Edward B.; Tibbetts, Brad M.; Skipper, Betty J.; Clark, Charles R.; Twerdok, Lorraine

    2011-01-01

    Chronic inhalation studies were conducted to compare the toxicity and potential carcinogenicity of evaporative emissions from unleaded gasoline (GVC) and gasoline containing the oxygenate methyl tertiary-butyl ether (MTBE; GMVC). The test materials were manufactured to mimic vapors people would be exposed to during refueling at gas stations. Fifty F344 rats per gender per exposure level per test article were exposed 6 h/d, 5 d/wk for 104 wk in whole body chambers. Target total vapor concentrations were 0, 2, 10, or 20 g/m3 for the control, low-, mid-, and high-level exposures, respectively. Endpoints included survival, body weights, clinical observations, organs weights, and histopathology. GVC and GMVC exerted no marked effects on survival or clinical observations and few effects on organ weights. Terminal body weights were reduced in all mid- and high-level GVC groups and high-level GMVC groups. The major proliferative lesions attributable to gasoline exposure with or without MTBE were renal tubule adenomas and carcinomas in male rats. GMV exposure led to elevated testicular mesothelioma incidence and an increased trend for thyroid carcinomas in males. GVMC inhalation caused an increased trend for testicular tumors with exposure concentration. Mid- and high-level exposures of GVC and GMVC led to elevated incidences of nasal respiratory epithelial degeneration. Overall, in these chronic studies conducted under identical conditions, the health effects in F344 rats following 2 yr of GVC or GMVC exposure were comparable in the production of renal adenomas and carcinomas in male rats and similar in other endpoints. PMID:21432714

  12. N-(tert-butoxycarbonyl)-?-aminoisobutyryl-?-aminoisobutyric acid methyl ester: two polymorphic forms in the space group P2(1)/n.

    PubMed

    Gebreslasie, Hadgu Girmay; Jacobsen, Øyvind; Görbitz, Carl Henrik

    2011-08-01

    The title compound (systematic name: methyl 2-{2-[(tert-butoxycarbonyl)amino]-2-methylpropanamido}-2-methylpropanoate), C(14)H(26)N(2)O(5), (I), crystallizes in the monoclinic space group P2(1)/n in two polymorphic forms, each with one molecule in the asymmetric unit. The molecular conformation is essentially the same in both polymorphs, with the ?-aminoisobutyric acid (Aib) residues adopting ? and ? values characteristic of ?-helical and mixed 3(10)- and ?-helical conformations. The helical handedness of the C-terminal residue (Aib2) is opposite to that of the N-terminal residue (Aib1). In contrast to (I), the closely related peptide Boc-Aib-Aib-OBn (Boc is tert-butoxycarbonyl and Bn is benzyl) adopts an ?(L)-P(II) backbone conformation (or the mirror image conformation). Compound (I) forms hydrogen-bonded parallel ?-sheet-like tapes, with the carbonyl groups of Aib1 and Aib2 acting as hydrogen-bond acceptors. This seems to represent an unusual packing for a protected dipeptide containing at least one ?,?-disubstituted residue. PMID:21817793

  13. DIPPR Project 871 For 1995 - Thermodynamic Properties and Ideal-Gas Enthalpies of Formation for Methyl Benzoate, Ethyl Benzoate, (R)-(+)-Limonene, Tert-Amyl Methyl Ether, Trans-Crotonaldehyde, and

    SciTech Connect

    Steele, W.V.

    2002-07-01

    Ideal-gas enthalpies of formation of methyl benzoate, ethyl benzoate, (R)-(+)-limonene, tert-amyl methyl ether, trans-crotonaldehyde, and diethylene glycol are reported. The standard energy of combustion and hence standard enthalpy of formation of each compound in the liquid phase has been measured using an oxygen rotating-bomb calorimeter without rotation. Vapor pressures were measured to a pressure limit of 270 kPa or the lower decomposition point for each of the six compounds using a twin ebulliometric apparatus. Liquid-phase densities along the saturation line were measured for each compound over a range of temperature (ambient to a maximum of 548 K). A differential scanning calorimeter was used to measure two-phase (liquid + vapor) heat capacities for each compound in the temperature region ambient to the critical temperature or lower decomposition point. For methyl benzoate and tert-amyl methyl ether, critical temperatures and critical densities were determined from the DSC results and corresponding critical pressures derived from the fitting procedures. Fitting procedures were used to derive critical temperatures, critical pressures, and critical densities for each of the remaining compounds. The results of the measurements were combined to derive a series of thermophysical properties including critical temperature, critical density, critical pressure, acentric factor, enthalpies of vaporization (restricted to within {+-}50 K of the temperature region of the experimentally determined vapor pressures), and heat capacities along the saturation line. Wagner-type vapor-pressure equations were derived for each compound. All measured and derived values were compared with those obtained in a search of the literature. Recommended critical parameters are listed for each of the compounds studied. Group-additivity parameters, useful in the application of the Benson gas-phase group-contribution correlations, were derived.

  14. Pulse radiolysis studies of the action of antioxidants in polyethylene and model systems: 4-methyl-2,6-di-t-butyl-phenol

    NASA Astrophysics Data System (ADS)

    Brede, Ortwin

    1995-11-01

    By taking as an example 4-methyl-2,6-di-t-butyl-phenol (ArOH), the possibilities of stabilizer action from the aspect of analysis of transient elementary reactions are discussed. Pulse radiolysis and laser photolysis enable the generation of a spectrum of reactive species such as electronically excited states, radical ions and radicals. For liquid alkane solutions of the phenol and a polyethylene doped with ArOH the different elementary reaction channels are compared, and it is found that the processes of radiation-induced ArOH reactions in alkanes and PE are considerably different.

  15. Octacoordinated Dioxo-Molybdenum Complex via Formal Oxidative Addition of Molecular Oxygen. Studies of Chemical Reactions Between M(CO)6 (M = Cr, Mo) and 2,4-Di-tert-butyl-6-(pyridin-2-ylazo)-phenol.

    PubMed

    Chatterjee, Ipsita; Saha Chowdhury, Nabanita; Ghosh, Pradip; Goswami, Sreebrata

    2015-06-01

    Reactions of M(CO)6 (M = Mo, Cr) and 2 mol of 2,4-di-tert-butyl-6-(pyridin-2-ylazo)-phenol ligand (HL) in air yielded [Mo(VI)O2(L(1)¯)2], 1, and [Cr(III)(L(1)¯)(L(•2)¯)], 2, respectively, in high yields. Formation of the Cr-complex is a substitution reaction, which is associated with electron transfer, while that of Mo is an example of molecular oxygen activation. Isolated monoradical chromium complex 2 is susceptible to oxidation. Accordingly the reaction of 2 with the oxidant, I2 produces a cationic nonradical complex of chemical composition [Cr(III)(L(1)¯)2]I3, [2]I3 in almost quantitative yield. All the isolated complexes are primarily characterized by various spectroscopic techniques and magnetic measurements. While the molybdenum complex is diamagnetic, the two chromium complexes behave as simple paramagnets: ?eff (295 K), 2.81 ?B and 3.79 ?B for 2 and [2]I3, respectively. Single-crystal three-dimensional X-ray structures of 1, 2, [2]I3 are reported. The geometry of the Mo-complex is square antiprism (octacoordination), and that of the Cr-complexes is distorted octahedral. Redox properties of the complexes are studied by cyclic voltammetry and constant potential coulometry. The data are analyzed based on density functional theoretical calculations of molecular orbitals of redox isomers of the Cr complexes. The results indicated that the redox events in the complexes occur at the ligand center. The oxidation state of Cr in 2 is further assessed by XPS measurements and compared with the reported systems. PMID:25978689

  16. Effects of intraperitoneal administration of the GABAB receptor positive allosteric modulator 2,6-di tert-butyl-4-(2-hydroxy-2,2-dimethyl-propyl)-phenol (CGP7930) on food intake in non-deprived rats.

    PubMed

    Ebenezer, Ivor S

    2012-09-01

    ?-Aminobutyric acid-(B) (GABA(B)) receptor positive allosteric modulators (PAMs) act on an allosteric site on the GABA(B) receptor to potentiate the effects of GABA and GABA(B) receptor agonists. It has previously been demonstrated that the GABA(B) receptor agonist baclofen increases food intake in non-deprived rats. The aim of this study was to investigate whether the GABA(B) receptor PAM 2,6-di tert-butyl-4-(2-hydroxy-2,2-dimethyl-propyl)-phenol (CGP7930) would (i) increase food intake, and (ii) potentiate the hyperphagic effects of baclofen in rats. In Experiment 1, the effects of intraperitoneal (i.p.) administration of CGP7930 (1, 6 and 12 mg/kg) was investigated on food intake in non-deprived male Wistar rats. The 12 mg/kg dose of CGP7930 significantly increased cumulative food intake 30, 60 and 120 min (P<0.05, in each case) after administration. The 1 and 6 mg/kg doses were without effect. In Experiment 2, the effects of pretreatment with CGP7930 (6 mg/kg; i.p.) 5 min prior to administration of baclofen (2mg/kg, i.p.) was investigated on 30min cumulative food intake in non-deprived male Wistar rats. Baclofen (2mg/kg) significantly increased food intake compared with vehicle treatment (P<0.01). CGP7930 (6 mg/kg) had no effect on feeding. However, pretreatment with CGP7930 (6 mg/kg) significantly potentiated the hyperphagic effects of baclofen (2mg/kg) (P<0.01). These findings show that CGP7930 increases food intake and enhances the hyperphagic effects of baclofen, and are consistent with in vitro studies that suggest that it potentiates the effects of endogenous GABA and GABA(B) receptor agonists by allosteric modulation of the GABA(B) receptor. PMID:22652431

  17. Reversal of age-related increase in brain protein oxidation, decrease in enzyme activity, and loss in temporal and spatial memory by chronic administration of the spin-trapping compound N-tert-butyl-alpha-phenylnitrone

    SciTech Connect

    Carney, J.M.; Starke-Reed, P.E.; Oliver, C.N.; Landum, R.W.; Cheng, M.S.; Wu, J.F.; Floyd, R.A. )

    1991-05-01

    Oxygen free radicals and oxidative events have been implicated as playing a role in bringing about the changes in cellular function that occur during aging. Brain readily undergoes oxidative damage, so it is important to determine if aging-induced changes in brain may be associated with oxidative events. Previously we demonstrated that brain damage caused by an ischemia/reperfusion insult involved oxidative events. In addition, pretreatment with the spin-trapping compound N-tert-butyl-alpha-phenylnitrone (PBN) diminished the increase in oxidized protein and the loss of glutamine synthetase (GS) activity that accompanied ischemia/reperfusion injury in brain. We report here that aged gerbils had a significantly higher level of oxidized protein as assessed by carbonyl residues and decreased GS and neutral protease activities as compared to young adult gerbils. We also found that chronic treatment with the spin-trapping compound PBN caused a decrease in the level of oxidized protein and an increase in both GS and neutral protease activity in aged Mongolian gerbil brain. In contrast to aged gerbils, PBN treatment of young adult gerbils had no significant effect on brain oxidized protein content or GS activity. Male gerbils, young adults (3 months of age) and retired breeders (15-18 months of age), were treated with PBN for 14 days with twice daily dosages of 32 mg/kg. If PBN administration was ceased after 2 weeks, the significantly decreased level of oxidized protein and increased GS and neutral protease activities in old gerbils changed in a monotonic fashion back to the levels observed in aged gerbils prior to PBN administration. We also report that old gerbils make more errors than young animals and that older gerbils treated with PBN made fewer errors in a radial arm maze test for temporal and spatial memory than the untreated aged controls.

  18. Quantum mechanical study and spectroscopic (FT-IR, FT-Raman, UV-Visible) study, potential energy surface scan, Fukui function analysis and HOMO-LUMO analysis of 3-tert-butyl-4-methoxyphenol by DFT methods.

    PubMed

    Saravanan, S; Balachandran, V

    2014-09-15

    This study represents an integral approach towards understanding the electronic and structural aspects of 3-tert-butyl-4-methoxyphenol (TBMP). Fourier-transform Infrared (FT-IR) and Fourier-transform Raman (FT-Raman) spectra of TBMP was recorded in the region 4000-400 cm(-1) and 3500-100 cm(-1), respectively. The molecular structures, vibrational wavenumbers, infrared intensities and Raman activities were calculated using DFT (B3LYP and LSDA) methods using 6-311++G (d,p) basis set. The most stable conformer of TBMP was identified from the computational results. The assignments of vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The first order hyperpolarizability (?0) and related properties (?, ?0 and ??) of TBMP have been discussed. The stability and charge delocalization of the molecule was studied by Natural Bond Orbital (NBO) analysis. UV-Visible spectrum and effects of solvents have been discussed and the electronic properties such as HOMO and LUMO energies were determined by time-dependent TD-DFT approach with B3LYP/6-311++G (d,p) level of theory. The molecule orbital contributions are studied by density of energy states (DOSs). The reactivity sites are identified by mapping the electron density into electrostatic potential surface (MEP). Mulliken analysis of atomic charges is also calculated. The thermodynamic properties at different temperatures were calculated, revealing the correlations between standard heat capacities, standard entropy and standard enthalpy changes with temperatures. Global hardness, global softness, global electrophilicity and ionization potential of the title compound are determined. PMID:24813291

  19. Different hydrogen-bonded chains in the crystal structures of three alkyl N-[(E)-1-(2-benzyl­idene-1-methyl­hydrazin­yl)-3-hy­droxy-1-oxopropan-2-yl]carbamates

    PubMed Central

    Noguiera, Thais C. M.; Pinheiro, Alessandra C.; Wardell, James L.; de Souza, Marcus V. N.; Abberley, Jordan P.; Harrison, William T. A.

    2015-01-01

    The crystal structures of three methyl­ated hydrazine carbamate derivatives prepared by multi-step syntheses from l-serine are presented, namely benzyl N-{(E)-1-[2-(4-cyanobenzylidene)-1-methylhydrazinyl]-3-hydroxy-1-oxopro­pan-2-yl}carbamate, C20H20N4O4, tert-butyl N-{(E)-1-[2-(4-cyanobenzylidene)-1-methylhydrazinyl]-3-hydroxy-1-oxopropan-2-yl}carbamate, C17H22N4O4, and tert-butyl N-[(E)-1-(2-benzylidene-1-methylhydrazinyl)-3-hydroxy-1-oxopro­pan-2-yl]carbamate, C16H23N3O4. One of them shows that an unexpected racemization has occurred during the mild-condition methyl­ation reaction. In each crystal structure, the mol­ecules are linked into chains by O—H?O hydrogen bonds, but with significant differences between them. PMID:26279859

  20. Different hydrogen-bonded chains in the crystal structures of three alkyl N-[(E)-1-(2-benzyl-idene-1-methyl-hydrazin-yl)-3-hy-droxy-1-oxopropan-2-yl]carbamates.

    PubMed

    Noguiera, Thais C M; Pinheiro, Alessandra C; Wardell, James L; de Souza, Marcus V N; Abberley, Jordan P; Harrison, William T A

    2015-07-01

    The crystal structures of three methyl-ated hydrazine carbamate derivatives prepared by multi-step syntheses from l-serine are presented, namely benzyl N-{(E)-1-[2-(4-cyanobenzylidene)-1-methylhydrazinyl]-3-hydroxy-1-oxopro-pan-2-yl}carbamate, C20H20N4O4, tert-butyl N-{(E)-1-[2-(4-cyanobenzylidene)-1-methylhydrazinyl]-3-hydroxy-1-oxopropan-2-yl}carbamate, C17H22N4O4, and tert-butyl N-[(E)-1-(2-benzylidene-1-methylhydrazinyl)-3-hydroxy-1-oxopro-pan-2-yl]carbamate, C16H23N3O4. One of them shows that an unexpected racemization has occurred during the mild-condition methyl-ation reaction. In each crystal structure, the mol-ecules are linked into chains by O-H?O hydrogen bonds, but with significant differences between them. PMID:26279859

  1. Calcium- and CaMKII-dependent chloride secretion induced by the microsomal Ca(2+)-ATPase inhibitor 2,5-di-(tert-butyl)-1,4-hydroquinone in cystic fibrosis pancreatic epithelial cells.

    PubMed Central

    Chao, A C; Kouyama, K; Heist, E K; Dong, Y J; Gardner, P

    1995-01-01

    Microsomal Ca(2+)-ATPase inhibitors such as thapsigargin (THG), cyclopiazonic acid (CPA) and 2,5-di-(tert-butyl)-1,4-hydroquinone (DBHQ) have been shown to inhibit Ca2+ reuptake by the intracellular stores and increase cytosolic free Ca2+ ([Ca2+]i). DBHQ is a commercially available non-toxic synthetic compound chemically unrelated to THG and CPA. In this study, we tested the feasibility of utilizing DBHQ to improve Cl- secretion via the Ca(2+)-dependent pathway, in the cystic fibrosis (CF)-derived pancreatic epithelial cell line CFPAC-1. DBHQ stimulated 125I efflux and mobilized intracellular free Ca2+ in a dose-dependent manner. The maximal effects were seen at concentrations of 25-50 microM. DBHQ (25 microM) caused a short-term rise in [Ca2+]i in the absence of ambient Ca2+, and a sustained elevation of [Ca2+]i in cell monolayers bathed in the efflux solution (1.2 mM Ca2+), which was largely attenuated by Ni2+ (5 mM). Bath-application of DBHQ induced an outwardly-rectifying whole-cell Cl- current, which was abolished by pipette addition of BAPTA (5 mM) or CaMK [273-302] (20 microM), an inhibitory peptide of multifunctional Ca2+/calmodulin-dependent protein kinase (CaMKII). Pretreatment of monolayers of CFPAC-1 cells with DBHQ for 4-5 min significantly increased the Ca(2+)-independent or autonomous activity of CaMKII assayed in the cell homogenates. Thus, DBHQ appears to enhance Cl- channel activity via a Ca(2+)-dependent mechanism involving CaMKII. Pretreatment of CFPAC-1 cells with up to 50 microM DBHQ for 6 h did not cause any detectable change in cell viability and did not significantly affect the cell proliferation rate. These results suggest that appropriate selective microsomal Ca(2+)-ATPase inhibitors may be therapeutically useful in improving Cl- secretion in CF epithelial cells. Images PMID:7560071

  2. Oxalic acid supported Si-18F-radiofluorination: one-step radiosynthesis of N-succinimidyl 3-(di-tert-butyl[18F]fluorosilyl)benzoate ([18F]SiFB) for protein labeling.

    PubMed

    Kostikov, Alexey P; Chin, Joshua; Orchowski, Katy; Niedermoser, Sabrina; Kovacevic, Miriam M; Aliaga, Antonio; Jurkschat, Klaus; Wängler, Bjoern; Wängler, Carmen; Wester, Hans-Jürgen; Schirrmacher, Ralf

    2012-01-18

    N-Succinimidyl 3-(di-tert-butyl[(18)F]fluorosilyl)benzoate ([(18)F]SiFB), a novel synthon for one-step labeling of proteins, was synthesized via a simple (18)F-(19)F isotopic exchange. A new labeling technique that circumvents the cleavage of the highly reactive active ester moiety under regular basic (18)F-labeling conditions was established. In order to synthesize high radioactivity amounts of [(18)F]SiFB, it was crucial to partially neutralize the potassium oxalate/hydroxide that was used to elute (18)F(-) from the QMA cartridge with oxalic acid to prevent decomposition of the active ester moiety. Purification of [(18)F]SiFB was performed by simple solid-phase extraction, which avoided time-consuming HPLC and yielded high specific activities of at least 525 Ci/mmol and radiochemical yields of 40-56%. In addition to conventional azeotropic drying of (18)F(-) in the presence of [K(+)?2.2.2.]C(2)O(4), a strong anion-exchange (SAX) cartridge was used to prepare anhydrous (18)F(-) for nucleophilic radio-fluorination omitting the vacuum assisted drying of (18)F(-). Using a lyophilized mixture of [K(+)?2.2.2.]OH resolubilized in acetonitrile, the (18)F(-) was eluted from the SAX cartridge and used directly for the [(18)F]SiFB synthesis. [(18)F]SiFB was applied to the labeling of various proteins in likeness to the most commonly used labeling synthon in protein labeling, N-succinimidyl-4-[(18)F]fluorobenzoate ([(18)F]SFB). Rat serum albumin (RSA), apo-transferrin, a ?-cell-specific single chain antibody, and erythropoietin were successfully labeled with [(18)F]SiFB in good radiochemical yields between 19% and 36%. [(18)F]SiFB- and [(18)F]SFB-derivatized RSA were directly compared as blood pool imaging agents in healthy rats using small animal positron emission tomography. Both compounds demonstrated identical biodistributions in healthy rats, accurately visualizing the blood pool with PET. PMID:22148255

  3. 2,4-Di-tert-butyl-6-({[2-(di-methyl-amino)-eth-yl](2-hy-droxy-benz-yl)amino}-meth-yl)phenol.

    PubMed

    Spaleniak, Grzegorz P; Bisz, Elwira; Bia?ek, Marzena; Zarychta, Bartosz

    2014-06-01

    The title compound, C26H40N2O2, has both its N atoms in trigonal-pyramidal geometries. The mol-ecular structure is stabilized by O-H?N and C-H?O hydrogen bonds. In the crystal, C-H?? inter-actions lead to the formation of a supramolecular helical chain along the b-axis direction. PMID:24940258

  4. (6S)-2,4-Di-tert-butyl-6-[(4S,5R)-3-iso­propyl-4-methyl-5-phenyloxazolidin-2-yl]phenol

    PubMed Central

    Campbell, Ian Sean; Edler, Kate L.; Parrott, Raleigh W.; Hitchcock, Shawn R.; Ferrence, Gregory M.

    2010-01-01

    The title oxazolidine compound, C27H39NO2, was synthesized from N-isopropyl­norephedrine. The dihedral angle between the aromatic rings is 70.33?(5)°. The N atom of the heterocycle is oriented to allow intra­molecular O—H?N hydrogen bonding with the hydr­oxy substituent. PMID:21580715

  5. (6S)-2,4-Di-tert-butyl-6-[(4S,5R)-3-iso-propyl-4-methyl-5-phenyloxazolidin-2-yl]phenol.

    PubMed

    Campbell, Ian Sean; Edler, Kate L; Parrott, Raleigh W; Hitchcock, Shawn R; Ferrence, Gregory M

    2010-01-01

    The title oxazolidine compound, C(27)H(39)NO(2), was synthesized from N-isopropyl-norephedrine. The dihedral angle between the aromatic rings is 70.33?(5)°. The N atom of the heterocycle is oriented to allow intra-molecular O-H?N hydrogen bonding with the hydr-oxy substituent. PMID:21580715

  6. 2,4-Di-tert-butyl-6-({[2-(di­methyl­amino)­eth­yl](2-hy­droxy­benz­yl)amino}­meth­yl)phenol

    PubMed Central

    Spaleniak, Grzegorz P.; Bisz, Elwira; Bia?ek, Marzena; Zarychta, Bartosz

    2014-01-01

    The title compound, C26H40N2O2, has both its N atoms in trigonal-pyramidal geometries. The mol­ecular structure is stabilized by O—H?N and C—H?O hydrogen bonds. In the crystal, C—H?? inter­actions lead to the formation of a supramolecular helical chain along the b-axis direction. PMID:24940258

  7. (6R)-2-tert-Butyl-6-[(4R,5S)-3-isopropyl-4-methyl-5-phenyl­oxazolidin-2-yl]phenol

    PubMed Central

    Koyanagi, Takaoki; Edler, Kate L.; Parrott, Raleigh W.; Hitchcock, Shawn R.; Ferrence, Gregory M.

    2010-01-01

    In the title compound, C23H31NO2, the lone pair on the nitro­gen atom is oriented to facilitate intra­molecular hydrogen bonding with the hydr­oxy group residing on the phenyl substituent. The five-membered ring adopts an envelope confornmation with the O atom at the flap. The absolute stereochemistry was verified by measurement of optical activity using a digital polarimeter. PMID:21580714

  8. (6R)-2-tert-Butyl-6-[(4R,5S)-3-isopropyl-4-methyl-5-phenyl-oxazolidin-2-yl]phenol.

    PubMed

    Koyanagi, Takaoki; Edler, Kate L; Parrott, Raleigh W; Hitchcock, Shawn R; Ferrence, Gregory M

    2010-01-01

    In the title compound, C(23)H(31)NO(2), the lone pair on the nitro-gen atom is oriented to facilitate intra-molecular hydrogen bonding with the hydr-oxy group residing on the phenyl substituent. The five-membered ring adopts an envelope confornmation with the O atom at the flap. The absolute stereochemistry was verified by measurement of optical activity using a digital polarimeter. PMID:21580714

  9. METABOLISM OF DIETHYL ETHER AND COMETABOLISM OF METHYL TERT-BUTYL ETHER BY A FILAMENTOUS FUNGUS, A GRAPHIUM SP. (R823426)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  10. Relations between the detection of methyl tert-butyl ether (MTBE) in surface and ground water and its content in gasoline

    USGS Publications Warehouse

    Moran, M.J.; Halde, M.J.; Clawges, R.M.; Zogorski, J.S.

    2000-01-01

    The relations between the content of MTBE in gasoline and the detection frequency of MTBE in ground and surface water were analyzed using the percent by volume of MTBE in gasoline provided by NIPER. For groundwater, 21 metropolitan areas had information on detection frequency and percent volume of MTBE in gasoline, while for surface water, only 9 metropolitan areas had this information. For groundwater, three cities, i.e., Columbia, SC, Harrisburg, PA, and Norfolk, VA, had values of MTBE in gasoline for only 2 sampling periods and had a MTBE in gasoline for only 2 sampling periods. The frequency of detection of MTBE in surface and ground water had a positive relation to content of MTBE in gasoline. The occurrence of the fuel additive MTBE in ground and surface water was related to its issue in gasoline. The frequency of detection of MTBE was higher in areas that use greater amounts of MTBE in gasoline. As the percent by volume of MTBE in gasoline increased, the frequency of detection of MTBE in ground and surface water increased.

  11. RELATIONS BETWEEN THE DETECTION OF METHYL TERT-BUTYL ETHER (MTBE) IN SURFACE AND GROUND WATER AND ITS CONTENT IN GASOLINE

    E-print Network

    AND ITS CONTENT IN GASOLINE By Michael J. Moran, Mike J. Halde, Rick M. Clawges and John S. Zogorski U in the United States as an octane enhancer and oxygenate in gasoline. Octane enhancement began in the late 1970's with the phase-out of tetraethyl lead from gasoline. The use of oxygenates was expanded

  12. Simulation of methyl tert-butyl ether (MTBE) transport to ground water from immobile sources of gasoline in the vadose zone

    USGS Publications Warehouse

    Lahvis, M.A.; Rehmann, L.C.

    1999-01-01

    The mathematical model, R-UNSAT, developed to simulate the transport of benzene and MTBE in representative sand and clay hydrogeologic systems was evaluated. The effects on groundwater were simulated for small, chronic-, and single-volume releases of gasoline trapped in unsaturated soil. Hydrocarbon biodegradation was simulated by using a dual Monod-type kinetics model that includes oxygen and the reactive constituents. MTBE was assumed to be non-reactive. For MTBE, infiltration had the greatest effect on transport to groundwater. Infiltration also affected mass losses of MTBE to the atmosphere, particularly, in fine-grained soils. Depth to groundwater and soil type primarily affected travel times of MTBE to groundwater, but could affect mass-loading rates to groundwater if infiltration is insignificant. For benzene, transport to groundwater was significant only if the depth to the water table was < 1 m or biodegradation was assumed to be negligible. Mass fluxed to groundwater were generally smaller for benzene than for MTBE by more than two orders of magnitude. Thus, water that recharges an aquifer beneath a spill can be enriched in MTBE relative to benzene when compared to the composition of water in equilibrium with gasoline.

  13. Concentrations and potential health risks of methyl tertiary-butyl ether (MTBE) in air and drinking water from Nanning, South China.

    PubMed

    Zhang, Li'e; Qin, Jian; Zhang, Zhiyong; Li, Qin; Huang, Jiongli; Peng, Xiaowu; Qing, Li; Liang, Guiqiang; Liang, Linhan; Huang, Yuman; Yang, Xiaobo; Zou, Yunfeng

    2016-01-15

    Levels of methyl tertiary-butyl ether (MTBE) in occupational air, ambient air, and drinking water in Nanning, South China, were investigated, and then their potential health risks to occupational workers and the general public were evaluated. Results show that the MTBE concentration in occupational air from 13 service stations was significantly higher than that in ambient air from residential areas (p<0.0001); both are far lower than the threshold limit value-time weighted average of MTBE regulated in the United States (US). The drinking water samples from household taps yielded detectable MTBE in the range of 0.04-0.33?g/L, which is below the US drinking water standard of 20-40?g/L. The non-carcinogenic risk of MTBE from air inhalation may be negligible because the calculated hazard quotient was less than 1. The mean MTBE lifetime cancer risk was within the acceptable limit of 1×10(-6) to 1×10(-4), but the lifetime cancer risk of refueling workers in the urban service station at the 95th percentile slightly exceeded the maximum acceptable carcinogen risk (1×10(-4)), indicating the potential carcinogenic health effects on the population highly exposed to MTBE in this region. The hazard index and carcinogenic risk of MTBE in drinking water were significantly lower than the safe limit of US Environmental Protection Agency, suggesting that drinking water unlikely poses significant health risks to the residents in Nanning. PMID:26479908

  14. Emission and fate assessment of methyl tertiary butyl ether in the Boston area airshed using a simple multimedia box model: comparison with urban air measurements.

    PubMed

    Kawamoto, Katsuya; Arey, J Samuel; Gschwend, Philip M

    2003-12-01

    Expected urban air concentrations of the gasoline additive methyl tertiary butyl ether (MTBE) were calculated using volatile emissions estimates and screening transport models, and these predictions were compared with Boston, MA, area urban air measurements. The total volatile flux of MTBE into the Boston primary metropolitan statistical area (PMSA) airshed was calculated based on estimated automobile nontailpipe emissions and the Universal Quasi-Chemical Functional-Group Activity Coefficient computed abundance of MTBE in gasoline vapor. The fate of MTBE in the Boston PMSA was assessed using both the European Union System for the Evaluation of Substances, which is a steady-state multimedia box model, and a simple airshed box model. Both models were parameterized based on the meteorological conditions observed during air sampling in the Boston area. Measured average urban air concentrations of 0.1 and 1 microg/m3 MTBE during February and September of 2000, respectively, were comparable to corresponding model predictions of 0.3 and 1 microg/m3 and could be essentially explained from estimated temperature-dependent volatile emissions rates, observed average wind speed (the airshed flushing rate), and reaction with ambient tropospheric hydroxyl radical (*OH), within model uncertainty. These findings support the proposition that one can estimate gasoline component source fluxes and use simple multimedia models to screen the potential impact of future proposed gasoline additives on urban airsheds. PMID:14700130

  15. Crosslinked superhydrophobic films fabricated by simply casting poly(methyl methacrylate-butyl acrylate-hydroxyethyl methacrylate)-b-poly(perfluorohexylethyl methacrylate) solution

    NASA Astrophysics Data System (ADS)

    Wen, Xiufang; Ye, Chao; Cai, Zhiqi; Xu, Shouping; Pi, Pihui; Cheng, Jiang; Zhang, Lijuan; Qian, Yu

    2015-06-01

    This study focuses on the preparation of superhydrophobic films by crosslinkable polymer material-Poly(methyl methacrylate-butyl acrylate-hydroxyethyl methacrylate)-b-Poly(perfluorohexylethyl methacrylate) (P (MMA-BA-HEMA)-b-PFMA) with a simple one-step casting process. Nanoscale micelle particles with core-shell structure was obtained by dissolving the polymer and curing agent in the mixture of acetone and 1H, 1H, 5H octafluoropentyl-1,1,2,2 tetrafluoroethyl ether (FHT). Superhydrophobic films were fabricated by casting the micelle solution on the glass slides. By controlling the polymer concentration and acetone/FHT volume ratio, superhydrophobic polymer film with water contact angle of 153.2 ± 2.1° and sliding angle of 4° was obtained. By introducing a curing agent into the micelle solution, mechanical properties of the films can be improved. The adhension grade and hardness of the crosslinked superhydrophobic films reached 2 grade and 3H, respectively. The hydrophobicity is attributed to the synergistic effect of micro-submicro-nano-meter scale roughness by nanoscale micelle particles and low surface energy of fluoropolymer. This procedure makes it possible for widespread applications of superhydrophobic film due to its simplicity and practicability.

  16. Synthesis and complexation properties of DTPA-N,N''-bis[bis(n-butyl)]-N'-methyl-tris(amide). Kinetic stability and water exchange of its Gd3+ complex.

    PubMed

    Jaszberényi, Z; Tóth, E; Kálai, T; Király, R; Burai, L; Brücher, E; Merbach, A E; Hideg, K

    2005-02-21

    A novel DTPA-tris(amide) derivative ligand, DTPA-N,N''-bis[bis(n-butyl)]-N'-methyl-tris(amide)(H2L3) was synthesized. With Gd3+, it forms a positively charged [Gd(L3)]+ complex, whereas with Cu2+ and Zn2+ [ML3], [MHL3]+ and [M2L3]2+ species are formed. The protonation constants of H2L3 and the stability constants of the complexes were determined by pH potentiometry. The stability constants are lower than those for DTPA-N,N''-bis[bis(n-butyl)amide)](H3L2), due to the lower negative charge and reduced basicity of the amine nitrogens in (L3)2-. The kinetic stability of [Gd(L3)]+ was characterised by the rates of metal exchange reactions with Eu3+, Cu2+ and Zn2+. The exchange reactions, which occur via proton and metal ion assisted dissociation of [Gd(L3)]+, are significantly slower than for [Gd(DTPA)]2-, since the amide groups cannot be protonated and interact only weakly with the attacking metal ions. The relaxivities of [Gd(L2)] and [Gd(L3)]+ are constant between 10-20 degrees C, indicating a relatively slow water exchange. Above 25 degrees C, the relaxivities decrease, similarly to other Gd3+ DTPA-bis(amide) complexes. The pH dependence of the relaxivities for [Gd(L3)]+ shows a minimum at pH approximately 9, thus differs from the behaviour of Gd3+-DTPA-bis(amides) which have constant relaxivities at pH 3-8 and an increase below and above. The water exchange rates for [Gd(L2)(H2O)] and [Gd(L3)(H2O)]+, determined from a variable temperature (17)O NMR study, are lower than that for [Gd(DTPA)(H2O)]2-. This is a consequence of the lower negative charge and decreased steric crowding at the water binding site in amides as compared to carboxylate analogues. Substitution of the third acetate of DTPA5- with an amide, however, results in a less pronounced decrease in kex than substitution of the first two acetates. The activation volumes derived from a variable pressure (17)O NMR study prove a dissociative interchange and a limiting dissociative mechanism for [Gd(L2)(H2O)] and [Gd(L3)(H2O)]+, respectively. PMID:15702179

  17. Solvation of sodium chloride in the 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide ionic liquid: a molecular dynamics study.

    PubMed

    Sieffert, Nicolas; Wipff, Georges

    2007-06-28

    We report molecular dynamics studies on the solvation of sodium chloride in the 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide ionic liquid ([BMI][Tf2N] IL). We first consider the potential of mean force for dissociating a single Na+Cl- ion pair, showing that the latter prefers to be undissociated rather than dissociated (by ca. 9 kcal/mol), with a free energy barrier of ca. 5 kcal/mol (at d approximately 5.2 A) for the association process. The preference for Na+Cl- association is also observed from a 100 ns molecular dynamics simulation of a concentrated solution, where the Na+Cl- ions tend to form oligomers and microcrystals in the IL. Conversely, the simulation of Na13Cl14- and Na14Cl13+ cubic microcrystals (with, respectively, Cl- and Na+ at the vertices) does not lead to dissolution in the IL. Among these, Na14Cl13+ is found to be better solvated than Na13Cl14-, mainly due to the stronger Na+...Tf2N- interactions as compared to the Cl-...BMI+ interactions at the vertices of the cube. We finally consider the solid/liquid interface between the 100 face of NaCl and the IL, revealing that, in spite of its polar nature, the crystal surface is solvated by the less polar IL components (CF3(Tf2N) and butyl(BMI) groups) rather than by the polar ones (O(Tf2N) and imidazolium(BMI) ring). Specific ordering at the interface is described for both Tf2N- anions and BMI+ cations. In the first IL layer, the ions are rather parallel to the surface, whereas in the second "layer" they are more perpendicular. A similar IL structure is found at the surface of the all-neutral Na0Cl0 solid analogue, confirming that the solvation of the crystal is rather "apolar", due to the mismatch between the IL and the crystal ions. Several comparisons with water, methanol, or different BMI+-based ILs as solvents are presented, allowing us to better understand the specificity of the ionic liquid-NaCl interactions. PMID:17550283

  18. Evaluation of offspring sex ratio, sex hormones and antioxidant enzymes following exposure to methyl tertiary butyl ether in adult male Sprague-Dawley rats

    PubMed Central

    Khalili, Leila; Gholami, Soghra; Ansari-Lari, Maryam

    2015-01-01

    Methyl tertiary butyl ether (MTBE) is an oxygenated fuel additive which has been used widely in many parts of the world. This experiment was performed to determine the effect of MTBE on offspring sex ratio, sex hormones and antioxidant enzymes. A total of 20 adult Sprague-Dawley male rats were divided into four groups and received 0, 400, 800 and 1600 mg/kg/day MTBE by gavages for 30 consecutive days. At the end of the experiment, blood samples were taken for determination of sex hormones and antioxidant enzymes. Then, male rats were mated with healthy unexposed female rats and sex of offspring was determined after birth. Sex ratio was 0.48, 0.50, 0.43 and 0.50 in 0, 400, 800 and 1600 mg/kg/day MTBE groups, respectively (P = 0.91). There was significant decreasing trend for luteinizing hormone (LH) and testosterone in experimental groups (rs = -0.50, P = 0.030 and rs = -0.67, P = 0.002, respectively). No changes were observed for superoxide dismutase. However, decrease in glutathione peroxidase (GPX) was observed in all treatment groups compared with control which was significant in 400 mg/kg/day MTBE group (P = 0.016). The present study showed that paternal exposure to oral MTBE has no effect on offspring sex ratio; while, MTBE exposure could exert dose-dependent changes in serum testosterone and LH in treatment groups. The results of the present study, need to be clarified in the future studies. PMID:26417352

  19. Exposure to carbon monoxide, methyl-tertiary butyl ether (MTBE), and benzene levels inside vehicles traveling on an urban area in Korea.

    PubMed

    Jo, W K; Park, K H

    1998-01-01

    This study was designed to allow systematic comparison of exposure on public (40-seater buses) and private (four passengers cars) transport modes for carbon monoxide (CO), methyl-tertiary butyl ether (MTBE), and benzene by carrying out simultaneous measurements along the same routes. There were statistically significant differences (p < 0.05) in the concentrations of all target compounds among the three microenvironments; inside autos; inside buses; and in ambient air. The target compounds were significantly correlated for all the three environments, with at least p < 0.05. The in-vehicle concentrations of MTBE and benzene were significantly higher (p < 0.0001), on the average 3.5 times higher, in the car with a carbureted engine than in the other three electronic fuel-injected cars. On the other hand, the CO concentrations were not significantly different among the four cars. The in-auto MTBE levels (48.5 micrograms/m3 as a median) measured during commutes in this study was 2-3 times higher than the New Jersey and Connecticut's results. The in-auto concentration of CO (4.8 ppm as a median) in this study was comparable with those in later studies in some American cities, but much lower than those in earlier studies in other American cities. The in-bus CO concentration was 3.6 ppm as a median. As a median, the in-auto concentration of benzene was 44.9 micrograms/m3, while the in-bus concentration 17.0 micrograms/m3. The in-auto/in-bus exposure ratios for all the target compounds was 31-40% higher than the corresponding concentration ratios, due to the higher travel speed on buses in the specified commute route as compared to the autos. PMID:9577748

  20. Development and application of a rat PBPK model to elucidate kidney and liver effects induced by ETBE and tert-butanol.

    PubMed

    Salazar, Keith D; Brinkerhoff, Christopher J; Lee, Janice S; Chiu, Weihsueh A

    2015-11-01

    Subchronic and chronic studies in rats of the gasoline oxygenates ethyl tert-butyl ether (ETBE) and tert-butanol (TBA) report similar noncancer kidney and liver effects but differing results with respect to kidney and liver tumors. Because TBA is a major metabolite of ETBE, it is possible that TBA is the active toxic moiety in all these studies, with reported differences due simply to differences in the internal dose. To test this hypothesis, a physiologically-based pharmacokinetic (PBPK) model was developed for ETBE and TBA to calculate internal dosimetrics of TBA following either TBA or ETBE exposure. This model, based on earlier PBPK models of methyl tert-butyl ether (MTBE), was used to evaluate whether kidney and liver effects are consistent across routes of exposure, as well as between ETBE and TBA studies, on the basis of estimated internal dose. The results demonstrate that noncancer kidney effects, including kidney weight changes, urothelial hyperplasia, and chronic progressive nephropathy (CPN), yielded consistent dose-response relationships across routes of exposure and across ETBE and TBA studies using TBA blood concentration as the dose metric. Relative liver weights were also consistent across studies on the basis of TBA metabolism, which is proportional to TBA liver concentrations. However, kidney and liver tumors were not consistent using any dose metric. These results support the hypothesis that TBA mediates the noncancer kidney and liver effects following ETBE administration; however, additional factors besides internal dose are necessary to explain the induction of liver and kidney tumors. PMID:26341290

  1. 21 CFR 178.2550 - 4-Hydroxymethyl-2,6-di-tert-butylphenol.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... § 178.2550 4-Hydroxymethyl-2,6-di-tert -butylphenol. 4-Hydroxymethyl-2,6-di-tert- butyl-phenol may be safely used as an antioxidant in articles intended for use in contact with food, in accordance with the...

  2. 21 CFR 178.2550 - 4-Hydroxymethyl-2,6-di-tert-butylphenol.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... SANITIZERS Antioxidants and Stabilizers § 178.2550 4-Hydroxymethyl-2,6-di-tert-butylphenol. 4-Hydroxymethyl-2,6-di-tert-butyl-phenol may be safely used as an antioxidant in articles intended for use in contact... solidification point of 140°-141 °C. (b) The concentration of the additive and any other permitted...

  3. 21 CFR 178.2550 - 4-Hydroxymethyl-2,6-di-tert-butylphenol.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... SANITIZERS Antioxidants and Stabilizers § 178.2550 4-Hydroxymethyl-2,6-di-tert-butylphenol. 4-Hydroxymethyl-2,6-di-tert-butyl-phenol may be safely used as an antioxidant in articles intended for use in contact... solidification point of 140°-141 °C. (b) The concentration of the additive and any other permitted...

  4. Comparison of Biostimulation versus Bioaugmentation with Bacterial Strain PM1 for Treatment of Groundwater Contaminated with Methyl Tertiary Butyl Ether (MTBE)

    PubMed Central

    Smith, Amanda E.; Hristova, Krassimira; Wood, Isaac; Mackay, Doug M.; Lory, Ernie; Lorenzana, Dale; Scow, Kate M.

    2005-01-01

    Widespread contamination of groundwater by methyl tertiary butyl ether (MTBE) has triggered the exploration of different technologies for in situ removal of the pollutant, including biostimulation of naturally occurring microbial communities or bioaugmentation with specific microbial strains known to biodegrade the oxygenate. After laboratory studies revealed that bacterial strain PM1 rapidly and completely biodegraded MTBE in groundwater sediments, the organism was tested in an in situ field study at Port Hueneme Naval Construction Battalion Center in Oxnard, California. Two pilot test plots (A and B) in groundwater located down-gradient from an MTBE source were intermittently sparged with pure oxygen. Plot B was also inoculated with strain PM1. MTBE concentrations up-gradient from plots A and B initially varied temporally from 1.5 to 6 mg MTBE/L. Six months after treatment began, MTBE concentrations in monitoring wells down-gradient from the injection bed decreased substantially in the shallow zone of the ground-water in plots A and B, thus even in the absence of the inoculated strain PM1. In the deeper zone, downstream MTBE concentrations also decreased in plot A and to a lesser extent in plot B. Difficulties in delivery of oxygen to the deeper zone of plot B, evidenced by low dissolved oxygen concentrations, were likely responsible for low rates of MTBE removal at that location. We measured the survival and movement of strain PM1 in groundwater samples using two methods for detection of DNA sequences specific to strain PM1: TaqMan quantitative polymerase chain reaction, and internal transcribed spacer region analysis. A naturally occurring bacterial strain with > 99% 16S rDNA sequence similarity to strain PM1 was detected in groundwater collected at various locations at Port Hueneme, including outside the plots where the organism was inoculated. Addition of oxygen to naturally occurring microbial populations was sufficient to stimulate MTBE removal at this site. In some cases, however, inoculation with an MTBE-degrading culture may be warranted. PMID:15743721

  5. Bestimmung der Aktivierungsparameter für die N-Inversion im 4-[(2,2-Dimethyl-aziridino-(1))-methyl]-2,6-di-tert.butyl-phenol durch 1H-DNMR / Evaluation of Activation Parameters for the N-Inversion of 4-[(2,2-Dimethyl-aziridino-(1))-methyl]- 2,6-di-tert.butyl-phenol by 1H-DNMR

    NASA Astrophysics Data System (ADS)

    1983-01-01

    Parts of the 1H-NMR spectra of the title substance show typical coalescence behaviour, which is analysed by line shape simulation. N-inversion is accounted for the dynamic process and rate constants and activation energies are given.

  6. A hydrogen-bridged adduct 3,4,6,7,8,9-hexa­hydro-2H-pyrimido[1,2-a]pyrimidin-1-ium [1,3-bis­(tert-butyl­dimethyl­sil­yloxy)-1,3-bis­(pyridin-2-yl)propan-2-yl­idene]nitro­nate acetonitrile monosolvate

    PubMed Central

    Schulz, Martin; Görls, Helmar; Westerhausen, Matthias

    2011-01-01

    The title compound, C7H14N3 +·C25H40N3O4Si2 ?·CH3CN, was obtained by the reaction of 2-nitro-1,3-di(pyridin-2-yl)-1,3-di(tert-butyl­dimethyl­sil­yloxy)propane with 1,3,4,6,7,8-hexa­hydro-2H-pyrimido[1,2-a]pyrimidine. Two hydrogen bonds stabilize the Lewis acid/base pair of the nitro­nate and the guanidinium moiety with N?O distances of 2.772?(3) and 2.732?(3)?Å. Both hydrogen atoms are more closely bound to the guanidinium [N—H distances of 0.83?(3) and 0.93?(3)?Å] than to the nitro­nate moiety. The nitro­nate is double-bonded to the respective carbon with an N=C bond length of 1.316?(3)?Å. PMID:22065493

  7. Crystal structure of the inclusion complex 25-benzo­ylmeth­oxy-5,11,17,23-tetra-tert-butyl-26,27,28-trihy­droxy-2,8,14,20-tetra­thia­calix[4]arene–tetra­ethyl­ammonium chloride (1/1)

    PubMed Central

    Akkurt, Mehmet; Jasinski, Jerry P.; Mohamed, Shaaban K.; Omran, Omran A.; Albayati, Mustafa R.

    2015-01-01

    The asymmetric unit of the title compound, C48H54O5S4·N(C2H5)4 +·Cl?, contains two tetra-tert-butyl-[(benzo­yl)meth­oxy]-trihy­droxy-tetra­thia­calix[4]arene mol­ecules, two tetra­ethyl­ammonium cations and two chloride anions. The two calixarene molecules in the asymmetric unit each display a cone conformation. There are no significant differences between the two independent molecules. The guest species do not sit within the calixarene ‘buckets’. In the crystal, extensive O—H?O, O—H?S and O—H?Cl hydrogen bonds and weak C—H?O, C—H?S and C—H?Cl inter­actions link the thia­calixarene mol­ecules, tetra­ethyl­ammonium cations and chloride anions, forming a three-dimensional network encompassing channels running parallel to the a-axis direction. The structure contains a solvent-accessible void of 76?(3)?Å3, but no solvent mol­ecule could reasonably be located. The crystal studied was an inversion twin with a 0.57?(8):0.43?(8) domain ratio. PMID:26594550

  8. Crystal structure of the inclusion complex 25-benzo-ylmeth-oxy-5,11,17,23-tetra-tert-butyl-26,27,28-trihy-droxy-2,8,14,20-tetra-thia-calix[4]arene-tetra-ethyl-ammonium chloride (1/1).

    PubMed

    Akkurt, Mehmet; Jasinski, Jerry P; Mohamed, Shaaban K; Omran, Omran A; Albayati, Mustafa R

    2015-11-01

    The asymmetric unit of the title compound, C48H54O5S4·N(C2H5)4 (+)·Cl(-), contains two tetra-tert-butyl-[(benzo-yl)meth-oxy]-trihy-droxy-tetra-thia-calix[4]arene mol-ecules, two tetra-ethyl-ammonium cations and two chloride anions. The two calixarene molecules in the asymmetric unit each display a cone conformation. There are no significant differences between the two independent molecules. The guest species do not sit within the calixarene 'buckets'. In the crystal, extensive O-H?O, O-H?S and O-H?Cl hydrogen bonds and weak C-H?O, C-H?S and C-H?Cl inter-actions link the thia-calixarene mol-ecules, tetra-ethyl-ammonium cations and chloride anions, forming a three-dimensional network encompassing channels running parallel to the a-axis direction. The structure contains a solvent-accessible void of 76?(3)?Å(3), but no solvent mol-ecule could reasonably be located. The crystal studied was an inversion twin with a 0.57?(8):0.43?(8) domain ratio. PMID:26594550

  9. Tert-butylhydroquinone as a phenolic activator of Nrf2 antagonizes arsenic-induced oxidative cytotoxicity but promotes arsenic methylation and detoxication in human hepatocyte cell line.

    PubMed

    Duan, Xiaoxu; Liu, Dan; Xing, Xiaoyue; Li, Jinlong; Zhao, Shuo; Nie, Huifang; Zhang, Yang; Sun, Guifan; Li, Bing

    2014-08-01

    Oxidative stress plays crucial roles in exerting a variety of damages upon arsenic exposure. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a master transcriptional regulator protecting cells and tissues from oxidative injuries. The objective of this study was to test whether tert-butylhydroquinone (tBHQ), a well-known synthetic Nrf2 inducer, could protect human hepatocytes against arsenic-induced cytotoxicity and oxidative injuries. Our results showed that 5 and 25 ?mol/l tBHQ pretreatment suppressed the arsenic-induced hepatocellular cytotoxicity, reactive oxygen species generation, and hepatic lipid peroxidation, while relieved the arsenic-induced disturbances of intracellular glutathione balance. In addition, we also observed that tBHQ treatment promoted the arsenic biomethylation process and upregulated Nrf2-regulated downstream heme oxygenase-1 and NADPH: quinine oxidoreductase 1 mRNA expressions. Collectively, we suspected that Nrf2 signaling pathway may be involved in the protective effects of tBHQ against arsenic invasion in hepatocytes. These data suggest that phenolic Nrf2 inducers, such as tBHQ, represent novel therapeutic or dietary candidates for the population at high risk of arsenic poisoning. PMID:24970285

  10. Positive allosteric modulation of native and recombinant gamma-aminobutyric acid(B) receptors by 2,6-Di-tert-butyl-4-(3-hydroxy-2,2-dimethyl-propyl)-phenol (CGP7930) and its aldehyde analog CGP13501.

    PubMed

    Urwyler, S; Mosbacher, J; Lingenhoehl, K; Heid, J; Hofstetter, K; Froestl, W; Bettler, B; Kaupmann, K

    2001-11-01

    The compounds CGP7930 [2,6-Di-tert-butyl-4-(3-hydroxy-2,2-dimethyl-propyl)-phenol] and its close analog CGP13501 were identified as positive modulators of gamma-aminobutyric acid(B) (GABA(B)) receptor function. They potentiate GABA-stimulated guanosine 5'-O-(3-[(35)S]thiotriphosphate) (GTP gamma[(35)S]) binding to membranes from a GABA(B(1b/2)) expressing Chinese hamster ovary (CHO) cell line at low micromolar concentrations and are ineffective in the absence of GABA. The structurally related compounds propofol and malonoben are inactive. Similar effects of CGP7930 are seen in a GTP gamma[(35)S] binding assay using a native GABA(B) receptor preparation (rat brain membranes). Receptor selectivity is demonstrated because no modulation of glutamate-induced GTP gamma[(35)S] binding is seen in a CHO cell line expressing the metabotropic glutamate receptor subtype 2. Dose-response curves with GABA in the presence of different fixed concentrations of CGP7930 reveal an increase of both the potency and maximal efficacy of GABA at the GABA(B(1b/2)) heteromer. Radioligand binding studies show that CGP7930 increases the affinity of agonists but acts at a site different from the agonist binding site. Agonist affinity is not modulated by CGP7930 at homomeric GABA(B(1b)) receptors. In addition to GTP gamma[(35)S] binding, we show that CGP7930 also has modulatory effects in cellular assays such as GABA(B) receptor-mediated activation of inwardly rectifying potassium channels in Xenopus laevis oocytes and Ca(2+) signaling in human embryonic kidney 293 cells. Furthermore, we show that CGP7930 enhances the inhibitory effect of L-baclofen on the oscillatory activity of cultured cortical neurons. This first demonstration of positive allosteric modulation at GABA(B) receptors may represent a novel means of therapeutic interference with the GABA-ergic system. PMID:11641424

  11. Recovery of anhydrous Na{sub 2}SO{sub 4} from SO{sub 2}-scrubbing liquor by extractive crystallization: Liquid-liquid equilibria for aqueous solutions of sodium carbonate, sulfate, and/or sulfite plus acetone, 2-propanol, or tert-butyl alcohol

    SciTech Connect

    Lynn, S.; Cos, R.; Prausnitz, J.M.; Schiozer, A.L.; Jaecksch, W.L.

    1996-11-01

    Sodium carbonate is a superior scrubbing agent for removing SO{sub 2} from combustion gases, but the resulting sodium sulfate (or sulfite) must be recovered for environmental reasons. Recovery by evaporative crystallization is energy-intensive; extractive crystallization provides an attractive alterative when technically feasible. Liquid/liquid equilibrium data were determined for two-phase mixtures containing aqueous solutions of sodium carbonate, sulfate, or sulfite and a polar organic solvent: acetone, 2-propanol, and 2-methylpropan-1-ol (i.e., tert-butyl alcohol). In the salt-saturated two-phase region, data were obtained between the lower consolute temperature and 60 C (50 C for acetone). data were also obtained at 35 C for liquid/liquid systems that were subsaturated with their respective salts and for liquid/liquid systems with overall molar ratios of sodium sulfite/sodium sulfate fixed at 25/75, 50/50, and 75/25. In the latter systems, it was found that the sulfite/sulfate ratios in the organic and aqueous phases were the same, i.e., there is no selectivity by these solvents for one salt relative to the other. The data show that any one of these solvents can be used to extract water from a concentrated solution of either sodium sulfite or sodium sulfate in a countercurrent extractor at 35 C, causing the anhydrous salt to crystallize. The wet solvent can be dried for recycle in a similar countercurrent operation at 35 C, using a saturated solution of Na{sub 2}CO{sub 3} as the drying agent. The number of moles of carbonate required for drying does not exceed the number of moles of sulfite-plus-sulfate precipitated. The process energy is about 0% of that required for single-stage evaporative crystallization of the same liquor.

  12. Identification and determination of tert-alkylphenols in carp from the Trenton Channel of the Detroit River, Michigan, USA.

    PubMed

    Shiraishi, H; Carter, D S; Hites, R A

    1989-07-01

    Whole carp from the Detroit River were analyzed by gas chromatographic mass spectrometry. Seven tertiary alkyl phenols (tert-pentylphenols, tert-butyl-tert-pentylphenols, a di-tert-pentylphenol and a tri-tert-pentylphenol) and eight chlorinated derivatives of these compounds were identified from their mass spectra and confirmed with synthesized authentic standards. 2,4-Di-tert-pentylphenol was the most abundant of these compounds; in one fish sample, its concentration was about 140 ppm. The same alkyl phenols were also found in technical-grade 2,4-di-tert-pentylphenol, which is manufactured at a chemical plant located near the Detroit River. Comparison of the alkyl phenol levels in carp with those in nearby sediments showed that many of these compounds are taken up by carp and that carp can be used to roughly track local sediment contamination. PMID:2775903

  13. '2+1' tricarbonyltechnetium(I)/tricarbonylrhenium(I) mixed-ligand complexes with methyl thiosalicylate and isocyanide ligands as potential precursors of radiopharmaceuticals.

    PubMed

    Ko?mi?ski, Przemys?aw; Gniazdowska, Ewa; Fuks, Leon; Kowalska, Sylwia

    2011-02-01

    The complexes of [(99m)Tc]-tricarbonyltechnetium(I) and [(188)Re]-tricarbonylrhenium(I), of the '2+1' type, with methyl thiosalicylate as an anionic bidentate ligand and with either tert-butyl 3-isocyanopropionate or glycine-glycine-tyrosine 4-isocyanobutyrate as monodentate ligands, have been prepared on the n.c.a. scale. The complexes exhibit different lipophilicity and high stability in neutral aqueous solutions. Based on the results of the challenge experiment with histidine, cysteine and glutathione the studied complexes might be considered to be promising models for radiopharmaceutical precursors. PMID:21129987

  14. Crystal structure of an unknown solvate of bis-(tetra-n-butyl-ammonium) [N,N'-(4-tri-fluoro-methyl-1,2-phenyl-ene)bis-(oxamato)-?(4) O,N,N',O']nickelate(II).

    PubMed

    Eya'ane Meva, François; Schaarschmidt, Dieter; Rüffer, Tobias

    2015-06-01

    In the title compound, [N(C4H9)4]2[Ni(C11H3F3N2O6)] or [N(n-Bu)4]2[Ni(topbo)] [n-Bu = n-butyl and topbo = 4-tri-fluoro-methyl-1,2-phenyl-enebis(oxamate)], the Ni(2+) cation is coordinated by two deprotonated amido N atoms and two carboxyl-ate O atoms, setting up a slightly distorted square-planar coordination environment. The [Ni(topbo](2-) anion lies on a twofold rotation axis. Due to an incompatibility with the point-group symmetry of the complete mol-ecule, orientational disorder of the CF3 group is observed. The tetra-hedral ammonium cations and the anion are linked by weak inter-molecular C-H?O and C-H?F hydrogen-bonding inter-actions into a three-dimensional network. A region of electron density was treated with the SQUEEZE procedure in PLATON [Spek (2015). Acta Cryst. C71, 9-18] following unsuccessful attempts to model it as plausible solvent mol-ecule(s). The given chemical formula and other crystal data do not take into account the unknown solvent mol-ecule. PMID:26090126

  15. Crystal structure of an unknown solvate of bis­(tetra-n-butyl­ammonium) [N,N?-(4-tri­fluoro­methyl-1,2-phenyl­ene)bis­(oxamato)-?4 O,N,N?,O?]nickelate(II)

    PubMed Central

    Eya’ane Meva, François; Schaarschmidt, Dieter; Rüffer, Tobias

    2015-01-01

    In the title compound, [N(C4H9)4]2[Ni(C11H3F3N2O6)] or [N(n-Bu)4]2[Ni(topbo)] [n-Bu = n-butyl and topbo = 4-tri­fluoro­methyl-1,2-phenyl­enebis(oxamate)], the Ni2+ cation is coordinated by two deprotonated amido N atoms and two carboxyl­ate O atoms, setting up a slightly distorted square-planar coordination environment. The [Ni(topbo]2? anion lies on a twofold rotation axis. Due to an incompatibility with the point-group symmetry of the complete mol­ecule, orientational disorder of the CF3 group is observed. The tetra­hedral ammonium cations and the anion are linked by weak inter­molecular C—H?O and C—H?F hydrogen-bonding inter­actions into a three-dimensional network. A region of electron density was treated with the SQUEEZE procedure in PLATON [Spek (2015). Acta Cryst. C71, 9–18] following unsuccessful attempts to model it as plausible solvent mol­ecule(s). The given chemical formula and other crystal data do not take into account the unknown solvent mol­ecule. PMID:26090126

  16. 40 CFR Appendix to Subpart Cc of... - Tables

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...isobutyl ketone (hexone) 108101 Methyl tert butyl ether 1634044 Naphthalene 91203 Phenol 108952 Toluene 108883 Trimethylpentane...108101 0.98 0.53 0.99 Methyl tert butyl ether 1634044 1.00 0.57 0.99...

  17. 27 CFR 21.101 - tert-Butyl alcohol.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...19 volumes of 60° Bé1. gasoline. (e) Freezing point (first needle). Above 20 °C. (f) Identification...and filter when cool). Heat the mixture just to the boiling point and remove from the flame. A yellow precipitate...

  18. 27 CFR 21.101 - tert-Butyl alcohol.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...19 volumes of 60° Bé1. gasoline. (e) Freezing point (first needle). Above 20 °C. (f) Identification...and filter when cool). Heat the mixture just to the boiling point and remove from the flame. A yellow precipitate...

  19. 27 CFR 21.101 - tert-Butyl alcohol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...solution to 80 ml of distilled water, and filter when cool). Heat the mixture just to the boiling point and remove from the...Odor. Characteristic odor. (i) Residual odor after evaporation. None. (j) Specific gravity at 25 °/25 °C....

  20. 27 CFR 21.101 - tert-Butyl alcohol.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...solution to 80 ml of distilled water, and filter when cool). Heat the mixture just to the boiling point and remove from the...Odor. Characteristic odor. (i) Residual odor after evaporation. None. (j) Specific gravity at 25 °/25 °C....

  1. 27 CFR 21.101 - tert-Butyl alcohol.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...solution to 80 ml of distilled water, and filter when cool). Heat the mixture just to the boiling point and remove from the...Odor. Characteristic odor. (i) Residual odor after evaporation. None. (j) Specific gravity at 25 °/25 °C....

  2. Crystal structure of tert-butyl­diphenyl­phosphine oxide

    PubMed Central

    Agbeworvi, George; Assefa, Zerihun; Sykora, Richard E.; Taylor, Jared D.

    2015-01-01

    In the structure of the title triorganophosphine oxide, C16H19OP, the P—O bond is 1.490?(1)?Å. The P atom has a distorted tetrahedral geometry. The O atom inter­acts with both phenyl groups of a neighboring mol­ecule [C?O = 2.930?(3) and 2.928?(4)?Å]. The C—O interaction directs an extended supramolecular arrangement along the a-axis. PMID:26090188

  3. The chemical behavior of terminally tert-butylated polyolefins

    PubMed Central

    Klein, Dagmar; Jones, Peter G; Dix, Ina; Hänel, Ralf

    2015-01-01

    Summary The chemical behavior of various oligoenes 2 has been studied. The catalytic hydrogenation of diene 3 yielded monoene 4. Triene 7 was hydrogenated to diene 8, monoene 9 and saturated hydrocarbon 10. Bromine addition to 3 and 7 yielded the dibromides 17 and 18, respectively, i.e., the oligoene system has been attacked at its terminal olefinic carbon atoms. Analogously, the higher vinylogs 19 and 20 yielded the 1,8- and 1,10-bromine adduts 23 and 24, respectively, when less than 1 equivalent of bromine was employed. Treatment of tetraene 19 with excess bromine provided tetrabromide 25. In epoxidation reactions, both with meta-chloroperbenzoic acid (MCPBA) and dimethyldioxirane (DMDO) two model oligoenes were studied: triene 7 and tetraene 19. Whereas 7 furnished the rearrangement product 31 with MCPBA, it yielded the symmetrical epoxide 32 with DMDO. Analogously, 19 was converted to mono-epoxide 33 with MCPBA and to 34 with DMDO. Diels–Alder addition of 7 with N-phenyltriazolinedione (PTAD) did not take place. Extension of the conjugated ?-system to the next higher vinylog, 19, caused NPTD-addition to the symmetrical adduct 37 in good yield. Comparable results were observed on adding NPTD (equivalent amount) to pentaene 20 and hexaene 21. Using 36 in excess provided the 2:1-adduct 40 from 21 and led to a complex mixture of adducts from heptaene 22. With tetracyanoethylene (TCNE) as the dienophile, tetraolefin 19 yielded the symmetrical adduct 43, although the reaction temperature had to be increased. Pentaene 20 and hexaene 21 led to corresponding results, adducts 44 and 45 being produced in acceptable yields. With nonaene 42 and TCNE the 2:1-adduct 48 was generated according to its spectroscopic data. Exploratory photochemical studies were carried out with tetraene 19 as the model compound. On irradiation this reacted with oxygen to the stable endo-peroxide 52. PMID:26425183

  4. Androgen and Progesterone Receptors Are Targets for Bisphenol A (BPA), 4-Methyl-2,4-bis-(P-Hydroxyphenyl)Pent-1-Ene--A Potent Metabolite of BPA, and 4-Tert-Octylphenol: A Computational Insight.

    PubMed

    Rehan, Mohd; Ahmad, Ejaz; Sheikh, Ishfaq A; Abuzenadah, Adel M; Damanhouri, Ghazi A; Bajouh, Osama S; AlBasri, Samera F; Assiri, Mansour M; Beg, Mohd A

    2015-01-01

    Exposure to toxic industrial chemicals that have capacity to disrupt the endocrine system, also known as endocrine disrupting chemicals (EDCs), has been increasingly associated with reproductive problems in human population. Bisphenol A (BPA; 4,4'-(propane-2,2-diyl)diphenol) and 4-tert-octylphenol (OP; 4-(1,1,3,3-tetramethylbutyl)phenol) are among the most common environmental contaminants possessing endocrine disruption properties and are present in plastics, epoxy resins, detergents and other commercial products of common personal and industrial use. A metabolite of BPA, 4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP) is about 1000 times more biologically active compared to BPA. Epidemiological, clinical, and experimental studies have shown association of BPA and OP with adverse effects on male and female reproductive system in human and animals. The endocrine disruption activity can occur through multiple pathways including binding to steroid receptors. Androgen receptor (AR) and progesterone receptor (PR) are critical for reproductive tract growth and function. Structural binding characterization of BPA, MBP, and OP with AR and PR using molecular docking simulation approaches revealed novel interactions of BPA with PR, and MBP and OP with AR and PR. For BPA, MBP, and OP, five AR interacting residues Leu-701, Leu-704, Asn-705, Met-742, and Phe-764 overlapped with those of native AR ligand testosterone, and four PR interacting residues Leu-715, Leu-718, Met-756, and Met-759 overlapped with those of PR co-complex ligand, norethindrone. For both the receptors the binding strength of MBP was maximum among the three compounds. Thus, these compounds have the potential to block or interfere in the binding of the endogenous native AR and PR ligands and, hence, resulting in dysfunction. The knowledge of the key interactions and the important amino-acid residues also allows better prediction of potential of xenobiotic molecules for disrupting AR- and PR-mediated pathways, thus, helping in design of less potent alternatives for commercial use. PMID:26379041

  5. Androgen and Progesterone Receptors Are Targets for Bisphenol A (BPA), 4-Methyl-2,4-bis-(P-Hydroxyphenyl)Pent-1-Ene—A Potent Metabolite of BPA, and 4-Tert-Octylphenol: A Computational Insight

    PubMed Central

    Rehan, Mohd; Ahmad, Ejaz; Sheikh, Ishfaq A.; Abuzenadah, Adel M.; Damanhouri, Ghazi A.; Bajouh, Osama S.; AlBasri, Samera F.; Assiri, Mansour M.; Beg, Mohd A.

    2015-01-01

    Exposure to toxic industrial chemicals that have capacity to disrupt the endocrine system, also known as endocrine disrupting chemicals (EDCs), has been increasingly associated with reproductive problems in human population. Bisphenol A (BPA; 4,4'-(propane-2,2-diyl)diphenol) and 4-tert-octylphenol (OP; 4-(1,1,3,3-tetramethylbutyl)phenol) are among the most common environmental contaminants possessing endocrine disruption properties and are present in plastics, epoxy resins, detergents and other commercial products of common personal and industrial use. A metabolite of BPA, 4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP) is about 1000 times more biologically active compared to BPA. Epidemiological, clinical, and experimental studies have shown association of BPA and OP with adverse effects on male and female reproductive system in human and animals. The endocrine disruption activity can occur through multiple pathways including binding to steroid receptors. Androgen receptor (AR) and progesterone receptor (PR) are critical for reproductive tract growth and function. Structural binding characterization of BPA, MBP, and OP with AR and PR using molecular docking simulation approaches revealed novel interactions of BPA with PR, and MBP and OP with AR and PR. For BPA, MBP, and OP, five AR interacting residues Leu-701, Leu-704, Asn-705, Met-742, and Phe-764 overlapped with those of native AR ligand testosterone, and four PR interacting residues Leu-715, Leu-718, Met-756, and Met-759 overlapped with those of PR co-complex ligand, norethindrone. For both the receptors the binding strength of MBP was maximum among the three compounds. Thus, these compounds have the potential to block or interfere in the binding of the endogenous native AR and PR ligands and, hence, resulting in dysfunction. The knowledge of the key interactions and the important amino-acid residues also allows better prediction of potential of xenobiotic molecules for disrupting AR- and PR-mediated pathways, thus, helping in design of less potent alternatives for commercial use. PMID:26379041

  6. TERT promoter mutations and monoallelic activation of TERT in cancer

    PubMed Central

    Huang, F W; Bielski, C M; Rinne, M L; Hahn, W C; Sellers, W R; Stegmeier, F; Garraway, L A; Kryukov, G V

    2015-01-01

    Here we report that promoter mutations in telomerase (TERT), the most common noncoding mutations in cancer, give rise to monoallelic expression of TERT. Through deep RNA sequencing, we find that TERT activation in human cancer cell lines can occur in either mono- or biallelic manner. Without exception, hotspot TERT promoter mutations lead to the re-expression of only one allele, accounting for approximately half of the observed cases of monoallelic TERT expression. Furthermore, we show that monoallelic TERT expression is highly prevalent in certain tumor types and widespread across a broad spectrum of cancers. Taken together, these observations provide insights into the mechanisms of TERT activation and the ramifications of noncoding mutations in cancer. PMID:26657580

  7. TERT promoter mutations and monoallelic activation of TERT in cancer.

    PubMed

    Huang, F W; Bielski, C M; Rinne, M L; Hahn, W C; Sellers, W R; Stegmeier, F; Garraway, L A; Kryukov, G V

    2015-01-01

    Here we report that promoter mutations in telomerase (TERT), the most common noncoding mutations in cancer, give rise to monoallelic expression of TERT. Through deep RNA sequencing, we find that TERT activation in human cancer cell lines can occur in either mono- or biallelic manner. Without exception, hotspot TERT promoter mutations lead to the re-expression of only one allele, accounting for approximately half of the observed cases of monoallelic TERT expression. Furthermore, we show that monoallelic TERT expression is highly prevalent in certain tumor types and widespread across a broad spectrum of cancers. Taken together, these observations provide insights into the mechanisms of TERT activation and the ramifications of noncoding mutations in cancer. PMID:26657580

  8. First Examples of Dinickel Complexes Containing the N(3)Ni(&mgr;(2)-SR)(3)NiN(3) Core. Synthesis and Crystal Structures of [L(2)Ni(2)][BPh(4)](2) and [L(3)Ni(2)][BPh(4)](2) (L = 2,6-Di(aminomethyl)-4-tert-butyl-thiophenolate).

    PubMed

    Kersting, Berthold; Siebert, Dieter

    1998-07-27

    A coordinatively unsaturated dinuclear Ni(II) complex of the tridentate ligand 2,6-di(aminomethyl)-4-tert-butyl-thiophenol (HL) has been synthesized and investigated in the context of ligand binding and oxidation state changes. The starting complex [L(2)Ni(2)][BPh(4)](2) (1) is readily prepared from NaL, NiCl(2).6H(2)O, and NaBPh(4) in methanol. Compound 1.CH(3)CN.CH(3)OH crystallizes from an acetonitrile/methanol mixed-solvent system in monoclinic space group P2(1)/n with a = 21.940(4) Å, b = 13.901(3) Å, c = 23.918(5) Å, beta = 110.00(3) degrees, and Z = 4. The structure consists of dinuclear [L(2)Ni(2)](2+) cations with two distorted planar cis-N(2)S(2)Ni coordination units joined by the thiophenolate sulfur atoms. The molecule has idealized C(2)(v)() symmetry. Complex 1 readily adds another 1 equiv of HL to afford the pale green complex [L(3)Ni(2)]Cl (2). The dinuclear structure and its formulation as a 3:2 complex (six-coordinate Ni ions) is derived from UV spectroscopy, cyclic voltammetry, and single-crystal X-ray diffraction of its oxidation product, [L(3)Ni(2)](2+). The dication was prepared by chemical oxidation of 2 with iodine in DMF and isolated as the dark brown BPh(4)(-) salt, [L(3)Ni(2)][BPh(4)](2).CH(3)OH (3), which crystallizes in monoclinic space group P2(1)/c with a = 23.678(5) Å, b = 20.090(4) Å, c = 16.797(3) Å, beta = 106.16(3) degrees, and Z = 4. Complex 3 is the first structurally characterized example that features a bioctahedral N(3)Ni(&mgr;(2)-SR)(3)NiN(3) core. Distortions from D(3)(h)() symmetry suggest that 3 is a trapped-valence Ni(II)Ni(III) compound. The Ni-S and Ni-N bond lengths vary from 2.2975(9) to 2.4486(12) Å and from 2.027(3) to 2.120(3) Å, respectively. On the CV time scale complex 2 undergoes two reversible electron-transfer reactions at E(1/2) = -0.02 and +0.44 V vs SCE, affording 3 and the transient dark green trication [L(3)Ni(2)](3+) (tau(1/2) approximately 15 min at 295 K), respectively. While 2 is EPR silent, the EPR spectrum of a powdered sample of 3 reveals g( perpendicular) = 4.0 and g( parallel) = 2.09 at 77 K, consistent with an S = (3)/(2) spin state of the mixed-valent Ni(II)Ni(III) complex. PMID:11670485

  9. Crystal structure of (2-{[3,5-bis­(1,1-di­methyl­eth­yl)-4-hy­droxy­phen­yl](5-methyl-2H-pyrrol-2-yl­idene)meth­yl}-5-methyl-1H-pyrrolido-?2 N,N?)di­fluoridoboron

    PubMed Central

    Morimoto, Yukio; Ogawa, Keizo; Uto, Yoshihiro; Nagasawa, Hideko; Hori, Hitoshi

    2015-01-01

    The title compound, C25H31BF2N2O, is a potential boron tracedrug in boron neutron capture therapy (BNCT), in which the B atom adopts a distorted BN2F2 tetra­hedral geometry: it is soluble in dimethyl sulfoxide, di­methyl­formamide and methanol. The pyrrolyl­idene­methyl­pyrrole triple fused ring system is almost planar (r.m.s. deviation = 0.031?Å) and subtends a dihedral angle of 47.09?(5)° with the plane of the pendant phenol ring. The phenol –OH group is blocked from forming hydrogen bonds by the adjacent bulky tert-butyl groups. In the crystal, inversion dimers linked by pairs of very weak C—H?F inter­actions generate R 2 2(22) loops. PMID:26396909

  10. Crystal structure of (2-{[3,5-bis-(1,1-di-methyl-eth-yl)-4-hy-droxy-phen-yl](5-methyl-2H-pyrrol-2-yl-idene)meth-yl}-5-methyl-1H-pyrrolido-?(2) N,N')di-fluoridoboron.

    PubMed

    Morimoto, Yukio; Ogawa, Keizo; Uto, Yoshihiro; Nagasawa, Hideko; Hori, Hitoshi

    2015-09-01

    The title compound, C25H31BF2N2O, is a potential boron tracedrug in boron neutron capture therapy (BNCT), in which the B atom adopts a distorted BN2F2 tetra-hedral geometry: it is soluble in dimethyl sulfoxide, di-methyl-formamide and methanol. The pyrrolyl-idene-methyl-pyrrole triple fused ring system is almost planar (r.m.s. deviation = 0.031?Å) and subtends a dihedral angle of 47.09?(5)° with the plane of the pendant phenol ring. The phenol -OH group is blocked from forming hydrogen bonds by the adjacent bulky tert-butyl groups. In the crystal, inversion dimers linked by pairs of very weak C-H?F inter-actions generate R 2 (2)(22) loops. PMID:26396909

  11. IRIS Toxicological Review of tert-butyl alcohol (tert-butanol) (Preliminary Assessment Materials)

    EPA Science Inventory

    In August 2013, EPA released the draft literature searches and associated search strategies, evidence tables, and exposure response arrays for TBA to obtain input from stakeholders and the public prior to developing the draft IRIS assessment. Specifically, EPA was interested in c...

  12. 1-tert-butyl-3-[6-(3,5-dimethoxy-phenyl)-2-(4-diethylamino-butylamino)-pyrido[2,3-d]pyrimidin-7-yl]-urea (PD173074), a selective tyrosine kinase inhibitor of fibroblast growth factor receptor-3 (FGFR3), inhibits cell proliferation of bladder cancer carrying the FGFR3 gene mutation along with up-regulation of p27/Kip1 and G1/G0 arrest.

    PubMed

    Miyake, Makito; Ishii, Masazumi; Koyama, Naoki; Kawashima, Kiyotaka; Kodama, Tetsuro; Anai, Satoshi; Fujimoto, Kiyohide; Hirao, Yoshihiko; Sugano, Kokichi

    2010-03-01

    Activating mutation of the fibroblast growth factor receptor-3 (FGFR3) gene is known as a key molecular event in both oncogenesis and cell proliferation of low-grade noninvasive human bladder urothelial carcinoma (UC), which is characterized by frequent intravesical recurrence. In this study, we investigated the antitumor potentiality of 1-tert-butyl-3-[6-(3,5-dimethoxy-phenyl)-2-(4-diethylamino-butylamino)-pyrido[2,3-d]pyrimidin-7-yl]-urea (PD173074), a small-molecule FGFR3-selective tyrosine kinase inhibitor (TKI), as a therapeutic modality using eight UC cell lines. In our in vitro cell proliferation assay, PD173074 suppressed cell proliferation remarkably in two cell lines, namely, UM-UC-14 and MGHU3, which expressed mutated FGFR3 protein. In contrast, the other six cell lines expressing wild-type FGFR3 or without FGFR3 expression were resistant to PD173074 treatment. Cell cycle analysis revealed the growth inhibitory effect of PD173074 was associated with arrest at G(1)-S transition in a dose-depending manner. Furthermore, we observed an inverse relationship between Ki-67 and p27/Kip1 expression after PD173074 treatment, suggesting that up-regulation of p27 recruited UC cells harboring activating FGFR3 mutations in G(1) that was analogous with the other receptor TKIs acting on the epidermal growth factor receptors. In the mouse xenograft models using subcutaneously transplanted UM-UC-14 and MGHU3, orally administered PD173074 suppressed tumor growth and induced apoptotic changes comparable with the results of our in vitro assay. These findings elucidated the effectiveness of molecular targeted approach for bladder UC harboring FGFR3 mutations and the potential utility to decrease the intravesical recurrence of nonmuscle invasive bladder UC after transurethral surgical resection. PMID:19955487

  13. Diagnostic Value of Methylated Human Telomerase Reverse Transcriptase in Human Cancers: A Meta-Analysis

    PubMed Central

    Gao, Wei; Shi, Yuan; Liu, Wei; Lin, Wei-Yin; Wu, Josh Chia-Ching; Chan, Jimmy Yu-Wai; Wong, Thian-Sze

    2015-01-01

    Human telomerase reverse transcriptase (hTERT) plays a critical role in the pathogenesis of human malignancies. Overexpression of hTERT is essential in controlling the propagation of cancer cells. The CpG island located at hTERT promoter region is subjected to methylation modification in human cancer. In this perspective article, we discussed the diagnostic value of methylated hTERT in human cancers. The definitive diagnosis of most solid tumors is based on histological and immunohistochemical features. Under certain circumstances, however, the use of methylated hTERT might be useful in overcoming the limitation of the conventional methods. Methylated hTERT showed a good diagnostic power in discriminating cancer from benign or normal tissues. Nevertheless, differences in detection method, methylation site, cancer type, and histological subtype of cancer make it difficult to evaluate the actual diagnostic accuracy of methylated hTERT. Therefore, we performed subgroup analysis to assess the effects of these factors on the diagnostic efficiency of methylated hTERT. We demonstrated that quantitative MSP (qMSP) assay offers the highest discriminative power between normal and cancer in comparison with different detection methods. In addition, the methylated sites selected by different studies had an impact on the detection performance. Moreover, the diagnostic power of methylated hTERT was affected by cancer type and histological subtype. In conclusion, the existing evidence demonstrated that methylated hTERT is effective in cancer detection. Detailed profiling of the methylation sites to local the common methylation hotspot across human cancers is warranted to maximize the diagnostic value of methylated hTERT in cancer detection.

  14. 40 CFR Table 1 to Subpart F of... - Synthetic Organic Chemical Manufacturing Industry Chemicals

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...branched) 123013 V Dodecyl phenol (branched) 121158585 V... 98851 II Methyl tert-butyl ether 1634044 V Methylamine...Phenetidine (p-) 156434 III Phenol 108952 III Phenolphthalein...Pyridine 110861 II p-tert-Butyl toluene 98511 III...

  15. NMR study of molecular motion in some molecules containing t-butyl groups

    NASA Astrophysics Data System (ADS)

    Yamauchi, Jun; McDowell, Charles A.

    1981-08-01

    Continuous wave and pulse NMR measurements were carried out on phenol derivatives containing t-butyl groups [tri-t-butylphenol (TTBP), methylene-bis(2,6-di-t-butylphenol) (MBBP), and the galvinoxyl radical] to investigate the molecular motions of methyl and t-butyl groups. From second moment measurements we distinguish three temperature regions characteristic of different forms of molecular motions. Between the rigid-lattice limit (plateau region III) and plateau region I at high temperature where both methyl and t-butyl motions are present, there appeared shoulders in the second moment curve. The shoulders in the second moments and relaxation minimum at low temperature are satisfactorily explained by the motional model which includes nonequivalent methyl motions; two methyls in each t-butyl group at the ortho positions and all methyls in the t-butyl group at the para positions are responsible for these phenomena, while one methyl motion in each t-butyl group at the ortho positions and the entire motion of the t-butyl group are considerably restricted at low temperature. The relaxation mechanism at high temperature is discussed in terms of the nonequivalent methyl motions, assuming that one methyl group rotates slowly at a rate almost equal to that of the t-butyl group motion. The short relaxation time of the galvinoxyl radical is explained in terms of the electron-nuclear interactions and almost equal-weight contributions from the dipolar and scalar (hyperfine) interactions were found to account fully for the experimentally measured values.

  16. Microsolvation and sp2-stereoinversion of monomeric ?-(2,6-di-tert-butylphenyl)vinyllithium as measured by NMR

    PubMed Central

    Knittl, Monika; Rossmann, Eva C

    2014-01-01

    Summary The ?-unsubstituted title compound dissolves in THF as a uniformly trisolvated monomer, whereas it forms exclusively disolvated monomers in tert-butyl methyl ether, Et2O, TMEDA, or toluene with TMEDA (1.4 equiv). This was established at low temperatures through the observation of separated NMR signals for free and lithium-coordinated ligands and/or through the patterns and magnitudes of 13C,6Li NMR coupling constants. An aggregated form was observed only with Et2O (2 equiv) in toluene as the solvent. The olefinic geminal interproton coupling constants of the H2C= part can be used as a secondary criterion to differentiate between these differently solvated ground-states (3, 2, or <2 coordinated ligands per Li). Due to a kinetic trisolvation privilege of THF, the cis/trans sp2-stereoinversion rates could be measured through analyses of 1H NMR line broadening and coalescence only in THF as the solvent: The pseudomonomolecular (because THF-catalyzed), ionic mechanism is initialized by a C–Li bond heterolysis with the transient immobilization of one additional THF ligand, followed by stereoinversion of the quasi-sp2-hybridized carbanionic center in cooperation with a “conducted tour” migration of Li+(THF)4 along the ?-aryl group within the solvent-separated ion pair. PMID:25383123

  17. 40 CFR Table 4 to Subpart F of... - Organic Hazardous Air Pollutants Subject to Cooling Tower Monitoring Requirements in § 63.104

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Hexone) 108101 Methyl methacrylate 80626 Methyl tert-butyl ether 1634044 Methylene chloride (Dichloromethane) 75092...91203 Nitrobenzene 98953 Nitropropane (2-) 79469 Phenol 108952 Phenylenediamine (p-) 106503 Phosgene...

  18. 40 CFR Table 2 to Subpart F of... - Organic Hazardous Air Pollutants

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...isocyanate 624839 Methyl methacrylate 80626 Methyl tert-butyl ether 1634044 Methylene chloride (Dichloromethane) 75092...100027 Nitropropane (2-) 79469 Phenanthrene 85018 Phenol 108952 Phenylenediamine (p-) 106503 Phosgene...

  19. Butyl benzyl phthalate

    Integrated Risk Information System (IRIS)

    Butyl benzyl phthalate ; CASRN 85 - 68 - 7 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinog

  20. Comparison of stabilization by Vitamin E and 2,6-di-tert-butylphenols during polyethylene radio-thermal-oxidation

    NASA Astrophysics Data System (ADS)

    Richaud, Emmanuel

    2014-10-01

    This paper reports a compilation of data for PE+Vitamin E and 2,6-di-tert-butylphenols oxidation in radio-thermal ageing. Data unambiguously show that Vitamin E reacts with Prad and POOrad whereas 2,6-di-tert-butyl phenols only react with POOrad . Kinetic parameters of the stabilization reactions for both kinds of antioxidants were tentatively extracted from phenol depletion curves, and discussed regarding the structure of the stabilizer. They were also used for completing an existing kinetic model used for predicting the stabilization by antioxidants. This one permits to compare the efficiency of stabilizer with dose rate or sample thickness.

  1. Analysis of Organic Molecules Extracted from Mars Analogues and Influence of Their Mineralogy Using N-Methyl-N-(tert-butyldimethylsilyl)Trifluoroacetamide Derivatization Coupled with Gas Chromatography Mass Spectrometry in Preparation for the Sample Analysis at Mars Derivatization Experiment on the Mars Science Laboratory Mission

    NASA Technical Reports Server (NTRS)

    Stalport, F.; Glavin, D. P.; Eigenbrode, J. L.; Bish, D.; Blake, D.; Coll, P.; Szopa, C.; Buch, A.; McAdam, A.; Dworkin, J. P.; Mahaffy, P. R.

    2012-01-01

    The search for complex organic molecules on Mars, including important biomolecules such as amino acids and carboxylic acids will require a chemical extraction and derivatization step to transform these organic compounds into species that are sufficiently volatile to be detected by gas chromatography mass spectrometry (GCMS). We have developed, a one-pot extraction and chemical derivatization protocol using N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) and dimethylformamide (DMF) for the Sample Analysis at Mars (SAM) experiment on the Mars Science Laboratory (MSL). The temperature and duration the derivatization reaction, pre-concentration of chemical derivatives, and gas chromatographic separation parameters have been optimized under SAM instrument design constraints. MTBSTFA/DMF extraction and derivatization at 300 C for several minutes of a variety of terrestrial Mars analogue materials facilitated the detection of amino acids and carboxylic acids in a surface soil sample collected from the Atacama Desert and a carbonate-rich stromatolite sample from Svalbard. However, the rapid reaction of MTBSTFA with water in several analogue materials that contained high abundances of hydrated minerals and the possible deactivation of derivatized compounds by iron oxides, as detected by XRD/XRF using the CheMin field unit Terra, proved to be highly problematic for the direct extraction of organics using MTBSTFA, The combination of pyrolysis and two different chemical derivatization methods employed by SAM should enable a wide range of organic compounds to be detected by GCMS if present on Mars,

  2. Crystal structure of hexa­kis­(?2-4-tert-but­oxy-4-oxobut-2-en-2-olato)trizinc

    PubMed Central

    Shtokvish, Olgerd O.; Koval, Lyudmila I.; Pekhnyo, Vasyl I.

    2014-01-01

    The title complex, systematic name hexa­kis­(?2-4-tert-but­oxy-4-oxobut-2-en-2-olato)-1:2?9 O 2,O 4:O 2;2:3?9 O 2,O 4:O 2-trizinc, [Zn3(C8H13O3)6], syn­the­sized from tert-butyl aceto­acetate and di­ethyl­zinc, consists of trinuclear centrosymmetric mol­ecules of an approximate C 3i symmetry. The three metal cations are arranged in a linear fashion, with the central ZnII atom located on a centre of symmetry. All three metal cations exhibit a distorted octa­hedral coordination geometry. The terminal ZnII cations are chelated by three tert-butyl aceto­acetate ligands and these units are connected to the central ZnII atom by the bridging enolate O atoms. PMID:25552972

  3. 40 CFR 60.707 - Chemicals affected by subpart RRR.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...alcohol 78-92-2 tert-Butyl alcohol 75-65-0 Butylbenzyl...phthalate 85-68-7 tert-Butyl hydroperoxide 75-91-2...872-50-4 Methyl tert-butyl ether Naphthalene 91-20-3...Perchloroethylene 127-18-4 Phenol 108-95-2...

  4. N-tert-Butoxycarbonylation of Structurally Diverse Amines and Sulfamides under Water-Mediated Catalyst-Free Conditions

    PubMed Central

    Cheraiet, Zinelaabine; Ouarna, Souad; Hessainia, Sihem; Berredjem, Malika; Aouf, Nour-Eddine

    2012-01-01

    A simple, efficient, and eco-friendly protocol for the N-Boc protection of the amine moiety in a variety of compounds with di-tert-butyl dicarbonate under water-acetone catalyst-free conditions is described. The corresponding monocarbamate is obtained in excellent yields on short reaction times. No competitive side reactions such as isocyanate urea and O-Boc were observed. This method represents a reasonable alternative to the previous reported protection procedures. PMID:24052842

  5. Magnetocaloric properties of manganese(III) porphyrins bearing 2,6-di-tert-butylphenol groups

    NASA Astrophysics Data System (ADS)

    Korolev, V. V.; Lomova, T. N.; Maslennikova, A. N.; Korolev, D. V.; Shpakovsky, D. B.; Zhang, Jianwei; Milaeva, E. R.

    2016-03-01

    Magnetocaloric effect (MCE) and heat capacity during the magnetization of (5,10,15,20-tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)porphynato) manganese (III) chloride (1), (5-(4-hydroxyphenyl)-10,15,20-tris(3,5-di-tert-butyl-4-hydroxyphenyl)porphynato) manganese (III) chloride (2), and (5-(4-palmitoyloxyphenyl)-10,15,20-tris(3,5-di-tert-butyl-4-hydroxyphenyl)porphynato) manganese (III) chloride (3) in their aqueous suspensions were determined by the microcalorimetric method over the temperature range of 278-320 K and in magnetic fields from 0 to 1 T. MCE was positive for all complexes studied, i.e. the magnetic field impression under adiabatic conditions led to an increase in temperature of the complexes suspensions. MCE increased with an increase in the magnetic field induction at all temperatures studied. Dependences of MCE on temperature had weak maxima at 298 K at all magnetic induction values. The disturbance of the intermolecular hydrogen-bonding of hydroxyl groups is one of probable reasons for such dependences type. MCE values increased under the palmitoyl substituent incorporation into one of the phenol groups at all temperatures. The heat capacity of the studied complexes rose slightly with temperature growth. Dependences of the heat capacity on temperature showed that the magnetic component of the heat capacity did not appear due to the presence of the manganese atom acting as a paramagnetic center in complexes 1, 2, and 3. The relation between the complexes structure and their magnetothermal properties was analyzed. It was justified that the changes of magnetothermal properties were caused by electronic substitution effects and, to an even greater degree, by the conditions of intermolecular hydrogen bonds formation in the paramagnetic materials.

  6. TERT promoter mutations in cancer development.

    PubMed

    Heidenreich, Barbara; Rachakonda, P Sivaramakrishna; Hemminki, Kari; Kumar, Rajiv

    2014-02-01

    Human telomerase reverse transcriptase (TERT) encodes a rate-limiting catalytic subunit of telomerase that maintains genomic integrity. TERT expression is mostly repressed in somatic cells with exception of proliferative cells in self-renewing tissues and cancer. Immortality associated with cancer cells has been attributed to telomerase over-expression. The precise mechanism behind the TERT activation in cancers has mostly remained unknown. The newly described germline and recurrent somatic mutations in melanoma and other cancers in the TERT promoter that create de novo E-twenty six/ternary complex factors (Ets/TCF) binding sites, provide an insight into the possible cause of tumor-specific increased TERT expression. In this review we discuss the discovery and possible implications of the TERT promoter mutations in melanoma and other cancers. PMID:24657534

  7. Synthesis and in vivo evaluation of [18F]2-(4-(4-(2-(2-fluoroethoxy)phenyl)piperazin-1-yl)butyl)-4-methyl-1,2,4-triazine-3,5(2H,4H)-dione ([18F]FECUMI-101) as an imaging probe for 5-HT1A receptor agonist in nonhuman primates

    PubMed Central

    Majo, Vattoly J.; Milak, Matthew S.; Prabhakaran, Jaya; Mali, Pratap; Savenkova, Lyudmila; Simpson, Norman R.; Mann, J. John; Parsey, Ramin V.; Dileep Kumar, J. S.

    2013-01-01

    The 5-HT1AR partial agonist PET radiotracer, [11C]CUMI-101, has advantages over an antagonist radiotracer as it binds preferentially to the high affinity state of the receptor and thereby provides more functionally meaningful information. The major drawback of C-11 tracers is the lack of cyclotron facility in many health care centers thereby limiting widespread clinical or research use. We identified the fluoroethyl derivative, 2-(4-(4-(2-(2-fluoroethoxy)phenyl)piperazin-1-yl)butyl)-4-methyl-1,2,4-triazine-3,5(2H,4H)dione (FECUMI-101) (Ki = 0.1 nM; Emax = 77%; EC50 = 0.65 nM) as a partial agonist 5-HT1AR ligand of the parent ligand CUMI-101. FECUMI-101 is radiolabeled with F-18 by O-fluoroethylation of the corresponding desmethyl analogue (1) with [18F]fluoroethyltosylate in DMSO in the presence of 1.6 equiv. of K2CO3 in 45 ± 5% yield (EOS). PET shows [18F]FECUMI-101 binds specifically to 5-HT1AR enriched brain regions of baboon. The specificity of [18F]FECUMI-101 binding to 5-HT1AR was confirmed by challenge studies with the known 5-HT1AR ligand WAY100,635. These findings indicate that [18F]FECUMI-101 can be a viable agonist ligand for the in vivo quantification of high affinity 5-HT1AR with PET. PMID:23816046

  8. Comparative cytotoxicity between butylated hydroxytoluene and its methylcarbamate derivative, terbucarb, on isolated rat hepatocytes

    SciTech Connect

    Nakagawa, Y.; Yaguchi, K.; Suzuki, T. )

    1994-08-01

    Butylated hydroxytoluene (3,5-di-tert-butyl-4-hydroxytoluene; BHT) is widely used as phenolic antioxidant in processed foods, cosmetics and petroleum products. It is well known that high doses of BHT cause acute hepatic damage accompanied by centrilobular necrosis in rats. The hepatic damage is associated with prolonged depletion of glutathione (GSH). Terbucarb (2,6-di-tert-butyl-para-tolyl-methylcarbamate), which has a methylcarbamate group substituted for the phenol group on BHT, was developed as an insecticide and is also presently used as a herbicide on turfgrass. Despite the metabolic and toxicological details known about BHT in vivo and in vitro, no extensive studies have been reported on the metabolism and toxicity of Terbucarb. The isolated hepatocyte system provides a very useful system for the study of the temporal sequences leading to cell damage caused by chemicals and drugs. Here, using freshly isolated rat hepatocytes, we report on the comparative toxic effects of BHT and its methylcarbamate derivative, Terbucarb. 17 refs., 2 figs., 2 tabs.

  9. Protective effect of butylated hydroxylanisole against hydrogen peroxide-induced apoptosis in primary cultured mouse hepatocytes

    PubMed Central

    Hwang, Geun Hye; Jeon, Yu Jin; Han, Ho Jae; Park, Soo Hyun; Baek, Kyoung Min; Chang, Woochul; Kim, Joong Sun; Kim, Lark Kyun; Lee, You-Mie; Lee, Sangkyu; Bae, Jong-Sup; Jee, Jun-Goo

    2015-01-01

    Butylated hydroxyanisole (BHA) is a synthetic phenolic compound consisting of a mixture of two isomeric organic compounds: 2-tert-butyl-4-hydroxyanisole and 3-tert-butyl-4-hydroxyanisole. We examined the effect of BHA against hydrogen peroxide (H2O2)-induced apoptosis in primary cultured mouse hepatocytes. Cell viability was significantly decreased by H2O2 in a dose-dependent manner. Additionally, H2O2 treatment increased Bax, decreased Bcl-2, and promoted PARP-1 cleavage in a dose-dependent manner. Pretreatment with BHA before exposure to H2O2 significantly attenuated the H2O2-induced decrease of cell viability. H2O2 exposure resulted in an increase of intracellular reactive oxygen species (ROS) generation that was significantly inhibited by pretreatment with BHA or N-acetyl-cysteine (NAC, an ROS scavenger). H2O2-induced decrease of cell viability was also attenuated by pretreatment with BHA and NAC. Furthermore, H2O2-induced increase of Bax, decrease of Bcl-2, and PARP-1 cleavage was also inhibited by BHA. Taken together, results of this investigation demonstrated that BHA protects primary cultured mouse hepatocytes against H2O2-induced apoptosis by inhibiting ROS generation. PMID:25798044

  10. Inhibition of cell proliferation and induction of apoptosis by oleanane triterpenoid (CDDO-Me) in pancreatic cancer cells is associated with the suppression of hTERT gene expression and its telomerase activity

    SciTech Connect

    Deeb, Dorrah; Gao, Xiaohua; Liu, Yongbo; Kim, Sahn-Ho; Pindolia, Kirit R.; Arbab, Ali S.; Gautam, Subhash C.

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer CDDO-Me inhibits hTERT gene expression. Black-Right-Pointing-Pointer CDDO-Me inhibits hTERT protein expression. Black-Right-Pointing-Pointer CDDO-Me inhibits hTERT telomerase activity. Black-Right-Pointing-Pointer CDDO-Me inhibits hTERT regulatory proteins. -- Abstract: Methyl-2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oate (CDDO-Me) is a multifunctional oleanane synthetic triterpenoid with potent anti-inflammatory and antitumorigenic properties. The mechanisms of the antisurvival and apoptosis-inducing activities of CDDO-Me and related derivatives of oleanolic acid have been defined; however, to date, no study has been carried out on the effect of CDDOs on human telomerase reverse transcriptase (hTERT) gene or telomerase activity. Here we report for the first time that inhibition of cell proliferation and induction of apoptosis by CDDO-Me in pancreatic cancer cell lines is associated with the inhibition of hTERT gene expression, hTERT telomerase activity and a number of proteins that regulate hTERT expression and activity. Furthermore, abrogation or overexpression of hTERT protein altered the susceptibility of tumor cells to CDDO-Me. These findings suggest that telomerase (hTERT) is a relevant target of CDDO-Me in pancreatic cancer cells.

  11. MONITORED NATURAL ATTENUATION OF TERTIARY BUTYL ALCOHOL (TBA) IN GROUND WATER AT GASOLINE SPILL SITES

    EPA Science Inventory

    The state agencies that implement the Underground Storage Tank program rely heavily on Monitored Natural Attenuation (MNA) to clean up contaminants such as benzene and methyl tertiary butyl ether (MTBE) at gasoline spill sites. This is possible because the contaminants are biolo...

  12. 21 CFR 177.2470 - Polyoxymethylene copolymer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Hexamethylene bis(3,5-di-tert -butyl-4-hydroxy-hydro-cinnamate) (CAS Reg. No. 35074-77-2). Melamine-formaldehyde resin. 2,2?-Methylenebis(4-methyl-6-tert- butylphenol). Nylon 6/66, weight ratio...

  13. Induction of cytotoxicity, apoptosis and cell cycle arrest by 1-t-butyl carbamoyl, 7-methyl-indole-3-ethyl isothiocyanate (NB7M) in nervous system cancer cells

    PubMed Central

    Brard, Laurent; Singh, Rakesh K; Kim, Kyu Kwang; Lange, Thilo S; Sholler, Giselle L Saulier

    2008-01-01

    Our group has recently developed 1-tbutyl carbamoyl, 7-methyl-indole-3-ethyl isothiocyanate (NB7M), a novel indole ethyl isothiocyanate analog. We now describe its selective cytotoxicity in both central nervous system (CNS) and neuroblastoma (NB) cancer cells. In an effort to understand its mechanism of action we examined the effects of NB7M on apoptosis, cell cycle arrest, and pro-survival/mitogen-activated protein kinase (MAPK) signaling in neuroblastoma cells. NB7M proved highly cytotoxic to NB cell lines (SMS-KCNR, SK-N- SH, SH-SY5Y, IMR-32) with IC50 values ranging from 1.0–2.0 ?M, whereas lung fibroblasts were less affected (IC50?10 ?M). In the NCI 60 cell screen 1-dose assay, NB7M (10 ?M) reduced the growth (?89 to ?27 % growth) of CNS cancer cell lines SF-268, SF-295, SNB-75 (glioblastoma), SF-539 (gliosarcoma), and U251 (astroglioma) while SNB-19 glioblastoma cells were relatively resistant (19% growth). Hoechst staining of SMS-KCNR cells treated with NB7M (3 ?M) for 24 hrs exhibited significant chromatin condensation and DNA fragmentation, whereas Annexin-v/7AADstaining revealed that the majority of cells accumulated in the early-apoptotic and late-apoptotic/necrotic stages. NB7M treatment of SMS-KCNR and SH-SY5Y cells also led to the cleavage of procaspases-3, and PARP-1 while causing activation of pro-apoptotic MAPKs and down-regulation of pro-survival factors AKT and PI-3K. Furthermore, NB7M treatment caused S-phase arrest in SMSKCNR and G1-phase arrest in SH-SY5Y cells. NB7M is active against CNS cancers and NB. PMID:19920894

  14. Subtelomeric demethylation deregulated hTERT expression, telomerase activity, and telomere length in four nasopharyngeal carcinoma cell lines.

    PubMed

    Zhang, Zi-Xiong; Wang, Yan; Tao, Ze-Zhang; Chen, Shi-Ming; Xiao, Bo-Kui; Zhou, Tao

    2014-09-01

    Global DNA hypomethylation, in particular that of the gene promoter sequence in gene hypermethylation, is a well-known characteristic of human cancer. Subtelomeres are enriched CpG islands; methylation is believed to be a potential epigenetic regulator. However, regulation on the telomere length remains largely unknown. To demonstrate this correlation, four nasopharyngeal carcinoma cell lines (CNE, CNE1, CNE2, 5-8F) were treated for 72 hours with 0, 1, or 2.5??M of the demethylating agent 5-aza-2'-deoxycytidine (5-aza-dC). Subtelomeric (D4Z4) level methylation was evaluated with a bisulfite assay, the human telomerase catalytic subunit (hTERT) expression was assayed by reverse transcription-polymerase chain reaction, the telomerase activity was detected using a telomeric repeat amplification protocol assay, and the telomere length was measured by Southern blot terminal restriction fragment analysis. There was significant demethylation following 5-aza-dC treatment, and a strongly repressed hTERT expression decreased the telomerase activity and remarkably shortened telomeres. Thus, partial subtelomeric methylation does not repress hTERT expression; conversely, demethylation may downregulate hTERT expression and shorten telomeres. PMID:25153197

  15. Sprayed Coating Renews Butyl Rubber

    NASA Technical Reports Server (NTRS)

    Martin, R. B.

    1982-01-01

    Damaged butyl rubber products are renewed by spray technique originally developed for protective suits worn by NASA workers. A commercial two-part adhesive is mixed with Freon-113 (or equivalent) trichlorotrifluoroethane to obtain optimum viscosity for spraying. Mix is applied with an external-air-mix spray gun.

  16. Complementary treatment of siTERT for improving the antitumor effect of TERT-specific I-131 therapy.

    PubMed

    Kim, S; Youn, H; Song, M G; Kang, J H; Chung, H K; Lee, D S; Chung, J-K

    2012-04-01

    Sodium iodide symporter (NIS)-based radionuclide therapy provides an effective means of treating malignant tumors. However, it is sometimes inadequate because of limited effects on radio-resistant tumors, and thus, combination therapies with other therapeutic options have been requested to enhance its efficacy. Human telomerase reverse transcriptase (hTERT) has been reported to be involved in the progression of most cancers and also been viewed as a good candidate for targeting tumor. Application of TERT-specific radionuclide therapies using NIS gene transfer have been reported to treat TERT-positive tumors, but this approach only demonstrated tumor regression rather than eradication. As inhibiting TERT expression by introducing the hTERT-specific shRNA (siTERT) has been suggested as a therapeutic option, we investigated the complementary role of siTERT treatment after the TERT-specific I-131 therapy and its possibility as a novel anticancer therapeutic strategy. Retroviruses containing TERT promoter/NIS for TERT specific Radionuclide therapy and siTERT for TERT targeting antisense therapy were produced. Hep3B cells expressing TERT specific NIS (Hep3B-TERT/NIS) were xenografted into nude mouse and visualized with micro-SPECT/CT for monitoring NIS activity. The levels of hTERT mRNA, protein and its activity were confirmed by RT-PCR, Western blotting and Telomerase repeat amplification protocol assay. Cell proliferation was monitored by MTT assay and induced apoptosis was confirmed by Annexin-V-PI staining. Therapeutic effects of I-131 and/or siTERT were evaluated by clonogenic assay and mouse tumor model. Reduction of hTERT mRNA, protein and TERT activity by siTERT were observed in Hep3B-TERT/NIS cells. The viabilities of the infected cells were significantly decreased to 50% versus siScramble treated controls. The early apoptotic cell population was increased by siTERT. The survival rates of cells treated with siTERT or I-131 alone were 72.4±7.6% and 56.2±5.2%, respectively. However, the survival rate of cells treated with I-131 and siTERT were decreased to 22.1±2.8%. From mouse xenograft model, we also found that the siTERT gene therapy showed synergism to the radioiodine therapy for reducing tumor growth in vivo. Our Results suggested that complementary siTERT gene therapy offers a novel strategy of cancer therapy to improve the therapeutic efficacy of TERT-specific I-131. PMID:22301953

  17. 40 CFR 704.33 - P-tert-butylbenzoic acid (P-TBBA), p-tert-butyltoluene (P-TBT) and p-tert-butylbenzaldehyde (P-TBB).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false P-tert-butylbenzoic acid (P-TBBA), p-tert-butyltoluene (P-TBT) and p-tert-butylbenzaldehyde (P-TBB). 704.33 Section 704.33 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT REPORTING AND RECORDKEEPING REQUIREMENTS...

  18. Environmental chamber study of the photochemical reaction of ethyl methyl sulfide and NO(x).

    PubMed

    Wang, Kun; Du, Lin; Ge, Maofa

    2009-01-01

    A series of experiments were conducted in a self-made smog chamber at (300 +/- 1) K and 1.01 x 10(5) Pa to simulate the photochemical reaction of ethyl methyl sulfide (EMS) and NO(x). The results showed that the higher the initial concentration of EMS, the more ozone was generated in the simulative reactions. It was found that the light intensity plays a very important role in the evaluation of ozone formation potential for EMS. The parameters of d(O3-NO) and IR (incremental reactivity) were used to quantify the potential of EMS on ozone formation. The obtained maximum IR values in this article for the five simulative reactions were 1.55 x 10(-2), 0.99 x 10(-2), 1.36 x 10(-2), 2.47 x 10(-2), and 1.65 x 10(-2), respectively. A comparison between the results we obtained here and the results we obtained previously for di-tert-butyl peroxide and acetylene showed that the potential reactivity of EMS on ozone formation was at a relatively low level. PMID:19402412

  19. Steric effects on forming different by-products in the formylation reaction of 2,4-dialkylphenol (dialkyl = t-Bu/ t-Bu, t-Bu/Me and Me/Me) proved by their structural and spectral characterizations

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Chu, Zhaolian; Xu, Feng

    2008-08-01

    In the formylation reaction of 2,4-dialkylphenol (2,4-di- tert-butylphenol, 2- tert-butyl-4-methylphenol and 2,4-dimethylphenol) in the presence of hexamethylenetetramine, steric effects of alkyl groups play important roles in forming different types of by-products, namely 2,4-di- tert-butyl-6-[(6,8-di- tert-butyl-2 H-1,3-benzoxazin-3(4 H)-yl)methyl]phenol ( 1), 2- tert-butyl-4-methyl-6-[(6- tert-butyl-8-methyl-2 H-1,3-benzoxazin-3(4 H)-yl)methyl]phenol ( 2) and tris(2-hydroxy-3,5-dimethylbenzyl)amine hydrochlorate ( 3). These three compounds are fully characterized and single-crystal structures of 1 and 3 are further elucidated.

  20. (E)-2-tert-Butyl-6-[(naphthalen-1-yl)imino­meth­yl]phenol

    PubMed Central

    Jamjah, Roghayieh; Nekoomanesh, Mehdi; Zahedi, Roya; Zohuri, Gholamhossein; Afshar Taromi, Faramarz; Notash, Behrouz

    2012-01-01

    The asymmetric unit of the title Schiff base compound, C21H21NO, contains two crystallographicaly independent mol­ecules. The dihedral angles between the naphthalene mean plane and the benzene ring are 29.28?(8) and 26.92.(8)° in the two mol­ecules. An intra­molecular O—H?N hydrogen bond and weak intra­molecular C—H?O hydrogen bonds stabilize the structure of each independent mol­ecule. PMID:22347119

  1. 2-tert-Butyl-6-(cyclo­hexyl­imino­meth­yl)-4-meth­oxy­phenol

    PubMed Central

    Jamjah, Roghayieh; Nekoomanesh, Mehdi; Pourjafar, Tayebeh; Zohuri, Gholam Hossein; Afshartaromi, Faramarz; Notash, Behrouz

    2011-01-01

    The asymmetric unit of the title Schiff base compound, C18H27NO2, contains two independent mol­ecules in which the C=N bond lengths are 1.278?(2) and 1.280?(2)?Å and the cyclo­hexane rings adopt chair conformations. Intra­molecular O—H?N hydrogen bonding between hy­droxy and imine groups and weak C—H?O hydrogen bonds help to stabilize the mol­ecular structure. PMID:21837152

  2. 2-tert-Butyl-6-(cyclo-hexyl-imino-meth-yl)-4-meth-oxy-phenol.

    PubMed

    Jamjah, Roghayieh; Nekoomanesh, Mehdi; Pourjafar, Tayebeh; Zohuri, Gholam Hossein; Afshartaromi, Faramarz; Notash, Behrouz

    2011-07-01

    The asymmetric unit of the title Schiff base compound, C(18)H(27)NO(2), contains two independent mol-ecules in which the C=N bond lengths are 1.278?(2) and 1.280?(2)?Å and the cyclo-hexane rings adopt chair conformations. Intra-molecular O-H?N hydrogen bonding between hy-droxy and imine groups and weak C-H?O hydrogen bonds help to stabilize the mol-ecular structure. PMID:21837152

  3. (E)-2-tert-Butyl-6-[(naphthalen-1-yl)imino-meth-yl]phenol.

    PubMed

    Jamjah, Roghayieh; Nekoomanesh, Mehdi; Zahedi, Roya; Zohuri, Gholamhossein; Afshar Taromi, Faramarz; Notash, Behrouz

    2012-02-01

    The asymmetric unit of the title Schiff base compound, C(21)H(21)NO, contains two crystallographicaly independent mol-ecules. The dihedral angles between the naphthalene mean plane and the benzene ring are 29.28?(8) and 26.92.(8)° in the two mol-ecules. An intra-molecular O-H?N hydrogen bond and weak intra-molecular C-H?O hydrogen bonds stabilize the structure of each independent mol-ecule. PMID:22347119

  4. 2-Bromo-4-tert-butyl-6-[(pyridin-2-yl-imino)-meth-yl]phenol.

    PubMed

    Balasubramani, V; Vinuchakkaravarthy, T; Gopi, Sreeraj; Narasimhan, S; Velmurugan, D

    2011-12-01

    In the title compound, C(16)H(17)BrN(2)O, the pyridine and benzene rings are almost coplanar [dihedral angle = 1.3?(2)°]. An intra-molecular O-H?Br inter-action forms an S(5) ring motif. PMID:22199955

  5. 2,6-Di-tert-butyl-4-(dimethyl-amino-meth-yl)phenol.

    PubMed

    Zeng, Tao; Hou, Yu-Ping

    2007-01-01

    The title compound, C(17)H(29)NO, is an important hindered phenol derivative. The asymmetric unit contains two mol-ecules. Molecules inter-act through O-H?N hydrogen bonds to form a tetramer arranged around a twofold rotation axis. PMID:21200781

  6. 2,4-Di-tert-butyl-6-[(2,5-difluorophenyl)iminomethyl]phenol.

    PubMed

    Celik, Omer; Kasumov, Veli T; Sahin, Ertan

    2009-01-01

    In the title Schiff base, C(21)H(25)F(2)NO, the dihedral angle between the aromatic rings is 27.90(5)° and an intramolecular O-H?N hydrogen bond occurs. In the crystal, the molecules are linked by C-H?O, C-H?N and C-H?F interactions. PMID:21578379

  7. 2,4-Di-tert-butyl-6-[(2,5-difluorophenyl)iminomethyl]phenol

    PubMed Central

    Çelik, Ömer; Kasumov, Veli T.; ?ahin, Ertan

    2009-01-01

    In the title Schiff base, C21H25F2NO, the dihedral angle between the aromatic rings is 27.90(5)° and an intramolecular O—H?N hydrogen bond occurs. In the crystal, the molecules are linked by C—H?O, C—H?N and C—H?F interactions. PMID:21578379

  8. 2,6-Di-tert-butyl-4-(dimethyl­amino­meth­yl)phenol

    PubMed Central

    Zeng, Tao; Hou, Yu-Ping

    2008-01-01

    The title compound, C17H29NO, is an important hindered phenol derivative. The asymmetric unit contains two mol­ecules. Molecules inter­act through O—H?N hydrogen bonds to form a tetramer arranged around a twofold rotation axis. PMID:21200781

  9. Toxicity of 2,6-Di-tert-butyl-4-Nitrophenol (DBNP).

    PubMed

    Alexander, W K; Briggs, G B; Still, K R; Jederberg, W W; MacMahon, K; Baker, W H; Mackerer, C

    2001-04-01

    U.S. Navy submarines reported a yellowing of metal surfaces on their internal surfaces. The yellowing was initially identified on the painted steel bulkheads but further examination indicated that it was not limited to steel surfaces and included bedding, thread tape, Formica, plastisol covered hand-wheels, and aluminum lockers. Crew members also reported to the medical department that their skin turned yellow when they came in contact with these contaminated surfaces and requested information on the effects of exposure. Studies conducted by General Dynamics' Electric Boat Division (EBD) determined that the agent was 2,6-Di-tertbutyl-4-Nitrophenol (DBNP). 2,6-Di-butylphenol (DBP) is an antioxidant additive used in lubricating oils and hydraulic fluids. In the enclosed atmosphere of a submarine, the oil mist could be spread throughout the boat by venting the lube oil to the atmosphere. Submarines use electrostatic precipitators (ESP) to clean the air of particulate materials. During passage through the ESP, oil mist containing DBP is nitrated to DBNP, which is then moved throughout the boat in the ventilation system. Analysis of the EBD data indicated 24-hour exposure concentrations to be in the range of <3.0 to 122 ppb in the laboratory and submarine settings. Submarine crews may be exposed to these concentrations for as many as 24 hours/ day for 90 days during underway periods. Toxicity studies regarding the oral and dermal uptake of DBNP were conducted. From the literature the lethal dose to 50 percent of the population (LD50) of DBNP (rat) was reported by Vesselinovitch et al. in 1961 to be 500 mg/kg. Our studies indicated that the LD50 is in the range of 80 mg/kg in the rat. Our work also includes dermal absorption studies, which indicated that DBNP is not well absorbed through intact skin. Within this study, no no-observable adverse effect level (NOAEL) or lowest observable adverse effect level (LOAEL) was identified. Calculation of a reference dose was completed using standard methods based on the LD50 as a numerator with several uncertainty and modifying factors. EBD's determination of airborne concentrations aboard submarines fall in the range of these anticipated allowable concentrations and could indicate significant chronic exposures. No adverse effects from DBNP exposures have been reported to date. PMID:11318392

  10. Bis(?5-1-tert-butyl­inden­yl)nickel(II)

    PubMed Central

    Bauer, Heiko; Sun, Yu; Sitzmann, Helmut

    2011-01-01

    The title compound, [Ni(C13H15)2], shows a slightly distorted sandwich structure with two independent mol­ecules in the asymmetric unit. Both Ni atoms are located on crystallographic centres of inversion. PMID:22065650

  11. Photoelectron spectroscopy, gas phase acidity, and thermochemistry of tert-butyl hydroperoxide: Mechanisms for the rearrangement

    E-print Network

    Ellison, Barney

    knock,'' which limits the temperature range and efficiency of internal com- bustion engines,9 CNHMCH2­CH­11 10 12 cm3 molecule 1 s 1 . In combustion processes, alkylperoxyl radicals are formed by the rapid- peratures, and the rearrangement product RO2H is of practi- cal interest since it is implicated in ``engine

  12. Crystal structure of tert-butyl-N-phenyl­carbonitrilium tetra­chlorido­aluminate

    PubMed Central

    van Dijk, Tom; Zant, Dirk W.; Wolf, Robert; Lammertsma, Koop; Slootweg, J. Chris

    2014-01-01

    In the title compound, (C11H14N)[AlCl4], the nitrilium (systematic name: 2,2-dimethyl-N-phenyl­propane­nitrilium) ion adopts a slightly distorted linear configuration [C—N C = 178.87?(16) and N C—C = 179.13?(17)°]. In the crystal, while there are no inter­molecular hydrogen bonds, pairs of nitrilium ions are linked through ?–? inter­actions [inter–centroid distance = 3.8091?(13)?Å]. PMID:25484737

  13. TERT rearrangements are frequent in neuroblastoma and identify aggressive tumors.

    PubMed

    Valentijn, Linda J; Koster, Jan; Zwijnenburg, Danny A; Hasselt, Nancy E; van Sluis, Peter; Volckmann, Richard; van Noesel, Max M; George, Rani E; Tytgat, Godelieve A M; Molenaar, Jan J; Versteeg, Rogier

    2015-12-01

    Whole-genome sequencing detected structural rearrangements of TERT in 17 of 75 high-stage neuroblastomas, with five cases resulting from chromothripsis. Rearrangements were associated with increased TERT expression and targeted regions immediately up- and downstream of TERT, positioning a super-enhancer close to the breakpoints in seven cases. TERT rearrangements (23%), ATRX deletions (11%) and MYCN amplifications (37%) identify three almost non-overlapping groups of high-stage neuroblastoma, each associated with very poor prognosis. PMID:26523776

  14. Binding properties and structure-affinity relationships of food antioxidant butylated hydroxyanisole and its metabolites with lysozyme.

    PubMed

    Wu, Di; Yan, Jin; Tang, Peixiao; Li, Shanshan; Xu, Kailin; Li, Hui

    2015-12-01

    Considering the harmful impact of food antioxidants on human bodies, thoroughly exposing their potential effects at the molecular level is important. In this study, the binding interactions of butylated hydroxyanisole (BHA), a phenolic antioxidant, and its different major metabolites tert-butylhydroquinone (TBHQ) and tert-butylbenzoquinone (TBQ) with lysozyme were examined via fluorescence, three-dimensional fluorescence, circular dichroism (CD), and ligand-protein docking studies. The three compounds caused strong quenching of lysozyme fluorescence by a static quenching mechanism but with different quenching efficiencies and different effects on the ?-helix content of the lysozyme. The order of binding affinity of lysozyme for all test compounds is as follows: BHA>TBQ>TBHQ. Thermodynamic parameters indicated that hydrogen bonding and van der Waals forces perform dominant functions in the binding between these compounds and lysozyme. Furthermore, structure-affinity relationships between the model compounds and lysozyme were established on the basis of computational analyses. PMID:26041206

  15. 27 CFR 21.118 - Methyl n-butyl ketone.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants... (a) Acidity (as acetic acid). 0.02 percent by weight, maximum. (b) Color. Colorless. (c) Odor....

  16. 27 CFR 21.118 - Methyl n-butyl ketone.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    .... Colorless. (c) Odor. Characteristic odor. (d) Refractive index at 20 °C. 1.396 to 1.404. (e) Specific gravity at 20 °/20 °C. 0.800 to 0.835. (f) Distillation range. No distillate should come over below 123...

  17. 27 CFR 21.118 - Methyl n-butyl ketone.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .... Colorless. (c) Odor. Characteristic odor. (d) Refractive index at 20 °C. 1.396 to 1.404. (e) Specific gravity at 20 °/20 °C. 0.800 to 0.835. (f) Distillation range. No distillate should come over below 123...

  18. 27 CFR 21.118 - Methyl n-butyl ketone.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... Colorless. (c) Odor. Characteristic odor. (d) Refractive index at 20 °C. 1.396 to 1.404. (e) Specific gravity at 20 °/20 °C. 0.800 to 0.835. (f) Distillation range. No distillate should come over below 123...

  19. 27 CFR 21.118 - Methyl n-butyl ketone.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .... Colorless. (c) Odor. Characteristic odor. (d) Refractive index at 20 °C. 1.396 to 1.404. (e) Specific gravity at 20 °/20 °C. 0.800 to 0.835. (f) Distillation range. No distillate should come over below 123...

  20. 27 CFR 21.118 - Methyl n-butyl ketone.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... Colorless. (c) Odor. Characteristic odor. (d) Refractive index at 20 °C. 1.396 to 1.404. (e) Specific gravity at 20 °/20 °C. 0.800 to 0.835. (f) Distillation range. No distillate should come over below 123...

  1. A methylation profile of in vitro immortalized human cell lines.

    PubMed

    Liu, Limin; Zhang, Jingmei; Bates, Steven; Li, Jian-Jian; Peehl, Dana M; Rhim, Johng S; Pfeifer, Gerd P

    2005-01-01

    Normal human diploid cells have a limited life span and undergo replicative senescence after various limited population doublings. Cells must pass the senescence barrier to become immortal. The exact mechanisms of immortalization are not clear, although inactivation of the RB pathway, and/or the p53 pathway and activation of telomerase has been shown to be necessary for immortalization of certain cell types with DNA viruses or hTERT. Methylation-associated inactivation of tumor suppressor genes plays an important role in tumor progression. To test if gene-specific methylation contributes to the immortalized and transformed phenotype, we analyzed the methylation status of 17 genes in normal cells immortalized with SV40, hTERT, Ad5, Ad12-SV40 or HPV-18. Some of these immortalized lines were progressively transformed and tumorigenic in nude mice. We observed gene-specific methylation in the in vitro immortalized and transformed cells. SV40 and HPV18 immortalization resulted in different methylation spectra. In SV40- and h-TERT-immortalized prostate epithelial cells, the most frequently methylated gene was RASSF1A, while in HPV18-immortalized cell lines, the RAR-beta2 gene was universally methylated. Immortalization with SV40 resulted in methylation of a greater number of genes than immortalization with HPV. Furthermore, in SV40-immortalized cell lines, methylation affected different genes in fibroblasts compared with epithelial cells, suggesting that different mechanisms may be used by SV40 to immortalize cell lines of different origins. In HPV18-immortalized and subsequently transformed cell lines, the most commonly methylated genes were hormone responsive genes, such as AR, ER-beta and RAR-beta2. In general, more genes were methylated in neoplastically-transformed cell lines than in only immortalized cell lines, indicating that accumulation of epigenetic abnormalities may contribute to oncogenesis. PMID:15586250

  2. Cancer-associated TERT promoter mutations abrogate telomerase silencing.

    PubMed

    Chiba, Kunitoshi; Johnson, Joshua Z; Vogan, Jacob M; Wagner, Tina; Boyle, John M; Hockemeyer, Dirk

    2015-01-01

    Mutations in the human telomerase reverse transcriptase (TERT) promoter are the most frequent non-coding mutations in cancer, but their molecular mechanism in tumorigenesis has not been established. We used genome editing of human pluripotent stem cells with physiological telomerase expression to elucidate the mechanism by which these mutations contribute to human disease. Surprisingly, telomerase-expressing embryonic stem cells engineered to carry any of the three most frequent TERT promoter mutations showed only a modest increase in TERT transcription with no impact on telomerase activity. However, upon differentiation into somatic cells, which normally silence telomerase, cells with TERT promoter mutations failed to silence TERT expression, resulting in increased telomerase activity and aberrantly long telomeres. Thus, TERT promoter mutations are sufficient to overcome the proliferative barrier imposed by telomere shortening without additional tumor-selected mutations. These data establish that TERT promoter mutations can promote immortalization and tumorigenesis of incipient cancer cells. PMID:26194807

  3. 21 CFR 182.3169 - Butylated hydroxyanisole.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Butylated hydroxyanisole. 182.3169 Section 182.3169 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 182.3169 Butylated hydroxyanisole. (a)...

  4. 21 CFR 182.3173 - Butylated hydroxytoluene.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Butylated hydroxytoluene. 182.3173 Section 182.3173 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 182.3173 Butylated hydroxytoluene. (a)...

  5. 21 CFR 182.3169 - Butylated hydroxyanisole.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Butylated hydroxyanisole. 182.3169 Section 182.3169 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 182.3169 Butylated hydroxyanisole. (a)...

  6. 21 CFR 582.3173 - Butylated hydroxytoluene.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Butylated hydroxytoluene. 582.3173 Section 582.3173 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 582.3173 Butylated hydroxytoluene....

  7. 21 CFR 582.3169 - Butylated hydroxyanisole.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Butylated hydroxyanisole. 582.3169 Section 582.3169 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 582.3169 Butylated hydroxyanisole....

  8. 21 CFR 182.3173 - Butylated hydroxytoluene.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Butylated hydroxytoluene. 182.3173 Section 182.3173 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 182.3173 Butylated hydroxytoluene. (a)...

  9. 40 CFR Table 2 to Subpart Jj of... - List of Volatile Hazardous Air Pollutants

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...isocyanate 624839 Methyl methacrylate 80626 Methyl tert-butyl ether 1634044 4,4?-Methylenebis (2-chloroaniline...N-Nitrosodimethylamine 62759 N-Nitrosomorpholine 59892 Phenol 108952 p-Phenylenediamine 106503 Phosgene...

  10. The Rotational Spectrum of Tertiary-Butyl Alcohol

    NASA Astrophysics Data System (ADS)

    Cohen, E. A.; Drouin, B. J.; Valenzuela, E. A.; Woods, R. C.; Caminati, W.; Maris, A.; Melandri, S.

    2009-06-01

    Tertiary-butyl alcohol is a nearly spherical rotor for which the internal rotation axis of the t-butyl group is close to the c molecular axis in the ac plane. Methyl group torsional spittings are not observed in the ground state. Its 8 to 40 GHz rotational spectrum was reported at this meeting by Valenzuela and Woods in 1974 and in more detail in 1975. The parameters derived at that time from a fit to the E states with J,K? 20 have provided the basis for extending the measurements to > 500 GHz. The combined data set extends to J,K > 50 and is fit with the program SPFIT using a common set of parameters for both the A and E states. The general features of the spectrum and the fitting procedure will be described. The resulting molecular constants and their interpretation will be discussed. E.A. Valenzuela, and R. C. Woods, Abstract MF6, International Symposium on Molecular Spectroscopy, Columbus, OH, 1974 E.A. Valenzuela, and R. C. Woods, Abstract RG15, International Symposium on Molecular Spectroscopy, Columbus, OH, 1975 E.A. Valenzuela, Ph.D. Thesis, University of Wisconsin-Madison, 1975. H. M. Pickett, J. Mol. Spectrosc. 148 (1991) 271-377.

  11. Methyl dynamics studied by ENDOR spectroscopy: a new method

    NASA Astrophysics Data System (ADS)

    Brustolon, Marina; Cassol, Teresa; Micheletti, Lauretta; Segre, Ulderico

    A new method for the investigation of methyl group rotation dynamics in free radicals in solids is described, based on the temperature dependence of the methyl protons ENDOR enhancement. The method is shown to work for hindering barriers of any height, and for both radicals trapped in single crystals and in powdered samples. As specific examples, the Arrhenius parameters for the methyl rotation in free radicals produced by ?-irradiation of 1-alanine and 4-methyl-2, 6 di-t-butyl-phenol are determined.

  12. Altered Histone Mark Deposition and DNA Methylation at Homeobox Genes in Human Oral Squamous Cell Carcinoma Cells

    PubMed Central

    Marcinkiewicz, Katarzyna M.; Gudas, Lorraine J.

    2014-01-01

    We recently reported a role of Polycomb repressive complex 2 (PRC2) and PRC2 trimethylation of histone 3 lysine 27 (H3K27me3) in the regulation of homeobox (HOX) (Marcinkiewicz and Gudas, 2013) gene transcript levels in human oral keratinocytes (OKF6-TERT1R) and tongue squamous cell carcinoma (SCC) cells. Here, we assessed both the levels of various histone modifications at a subset of homeobox genes and genome wide DNA methylation patterns in OKF6-TERT1R and SCC-9 cells by using ERRBS (enhanced reduced representation bisulfite sequencing). We detected the H3K9me3 mark at HOXB7, HOXC10, HOXC13 and HOXD8 at levels higher in OKF6-TERT1R than in SCC-9 cells; at IRX1 and SIX2 the H3K9me3 levels were conversely higher in SCC-9 than in OKF6-TERT1R. The H3K79me3 mark was detectable only at IRX1 in OKF6-TERT1R and at IRX4 in SCC-9 cells. The levels of H3K4me3 and H3K36me3 marks correlate with the transcript levels of the assessed homeobox genes in both OKF6-TERT1R and SCC-9. We detected generally lower CpG methylation levels on DNA in SCC-9 cells at annotated genomic regions which were differentially methylated between OKF6-TERT1R and SCC-9 cells; however, some genomic regions, including the HOX gene clusters, showed DNA methylation at higher levels in SCC-9 than OKF6-TERT1R. Thus, both altered histone modification patterns and changes in DNA methylation are associated with dysregulation of homeobox gene expression in human oral cavity SCC cells, and this dysregulation potentially plays a role in the neoplastic phenotype of oral keratinocytes. PMID:24519855

  13. Use of butyl-2-cyanoacrylate in rabbit auricular cartilage.

    PubMed

    Fung, R Q; Ronis, M L; Mohr, R M

    1985-07-01

    Since the nonsuture repair of blood vessels with methyl-2-cyanoacrylate was described in 1960, the advantages of a tissue adhesive over conventional sutures became evident. A survey of 115 otolaryngology programs showed that cyanoacrylates, mainly butyl-2-cyanoacrylate (B2C), are used more extensively than indicated in the literature. Cartilage grafts are commonly used in facial plastic procedures. In a study comparing B2C with conventional suture techniques in securing rabbit auricular cartilage autografts, sutures were used in the left control ear and B2C was used in the right experimental ear. Rabbits sacrificed at two weeks to 12 months showed graft viability in all samples and no statistically significant histologic difference between the grafts secured by either method. PMID:3893400

  14. Cancer. TERT promoter mutations and telomerase reactivation in urothelial cancer.

    PubMed

    Borah, Sumit; Xi, Linghe; Zaug, Arthur J; Powell, Natasha M; Dancik, Garrett M; Cohen, Scott B; Costello, James C; Theodorescu, Dan; Cech, Thomas R

    2015-02-27

    Reactivation of telomerase, the chromosome end-replicating enzyme, drives human cell immortality and cancer. Point mutations in the telomerase reverse transcriptase (TERT) gene promoter occur at high frequency in multiple cancers, including urothelial cancer (UC), but their effect on telomerase function has been unclear. In a study of 23 human UC cell lines, we show that these promoter mutations correlate with higher levels of TERT messenger RNA (mRNA), TERT protein, telomerase enzymatic activity, and telomere length. Although previous studies found no relation between TERT promoter mutations and UC patient outcome, we find that elevated TERT mRNA expression strongly correlates with reduced disease-specific survival in two independent UC patient cohorts (n = 35; n = 87). These results suggest that high telomerase activity may be a better marker of aggressive UC tumors than TERT promoter mutations alone. PMID:25722414

  15. Mutation of the TERT promoter, switch to active chromatin, and monoallelic TERT expression in multiple cancers.

    PubMed

    Stern, Josh Lewis; Theodorescu, Dan; Vogelstein, Bert; Papadopoulos, Nickolas; Cech, Thomas R

    2015-11-01

    Somatic mutations in the promoter of the gene for telomerase reverse transcriptase (TERT) are the most common noncoding mutations in cancer. They are thought to activate telomerase, contributing to proliferative immortality, but the molecular events driving TERT activation are largely unknown. We observed in multiple cancer cell lines that mutant TERT promoters exhibit the H3K4me2/3 mark of active chromatin and recruit the GABPA/B1 transcription factor, while the wild-type allele retains the H3K27me3 mark of epigenetic silencing; only the mutant promoters are transcriptionally active. These results suggest how a single-base-pair mutation can cause a dramatic epigenetic switch and monoallelic expression. PMID:26515115

  16. Metsulfuron-methyl-based herbicidal ionic liquids.

    PubMed

    Pernak, Juliusz; Niemczak, Micha?; Shamshina, Julia L; Gurau, Gabriela; G?owacki, Grzegorz; Praczyk, Tadeusz; Marcinkowska, Katarzyna; Rogers, Robin D

    2015-04-01

    Ten sulfonylurea-based herbicidal ionic liquids (HILs) were prepared by combining the metsulfuron-methyl anion with various cation types including quaternary ammonium ([bis(2-hydroxyethyl)methyloleylammonium](+), [2-hydroxyethyltrimethylammonium](+)), pyridinium ([1-dodecylpyridinium](+)), piperidinium ([1-methyl-1-propylpiperidinium](+)), imidazolium ([1-allyl-3-methylimidazolium](+), [1-butyl-3-methylimidazolium](+)), pyrrolidinium ([1-butyl-1-methylpyrrolidinium](+)), morpholinium ([4-decyl-4-methylmorpholinium](+)), and phosphonium ([trihexyltetradecylphosphonium](+) and [tetrabutylphosphonium](+)). Their herbicidal efficacy was studied in both greenhouse tests and field trials. Preliminary results for the greenhouse tests showed at least twice the activity for all HILs when compared to the activity of commercial Galmet 20 SG, with HILs with phosphonium cations being the most effective. The results of two-year field studies showed significantly less enhancement of activity than observed in the greenhouse; nonetheless, it was found that the herbicidal efficacy was higher than that of the commercial analog, and efficacy varied depending on the plant species. PMID:25734891

  17. Synthesis and Reactivity Comparisons of 1-Methyl-3-Substituted Cyclopropene Mini-tags for Tetrazine Bioorthogonal Reactions

    PubMed Central

    Yang, Jun; Liang, Yong; Še?kut?, Jolita

    2014-01-01

    Substituted cyclopropenes have recently attracted attention as stable “mini-tags” that are highly reactive dienophiles with the bioorthogonal tetrazine functional group. Despite this interest, the synthesis of stable cyclopropenes is not trivial and their reactivity patterns are poorly understood. Here, the synthesis and comparison of the reactivity of a series of 1-methyl-3-substituted cyclopropenes with different functional handles is described. The rates at which the various substituted cyclopropenes undergo Diels–Alder cycloadditions with 1,2,4,5-tetrazines were measured. Depending on the substituents, the rates of cycloadditions vary by over two orders of magnitude. The substituents also have a dramatic effect on aqueous stability. An outcome of these studies is the discovery of a novel 3-amidomethyl substituted methylcyclopropene tag that reacts twice as fast as the fastest previously disclosed 1-methyl-3-substituted cyclopropene while retaining excellent aqueous stability. Furthermore, this new cyclopropene is better suited for bioconjugation applications and this is demonstrated through using DNA templated tetrazine ligations. The effect of tetrazine structure on cyclopropene reaction rate was also studied. Surprisingly, 3-amidomethyl substituted methylcyclopropene reacts faster than trans-cyclooctenol with a sterically hindered and extremely stable tert-butyl substituted tetrazine. Density functional theory calculations and the distortion/interaction analysis of activation energies provide insights into the origins of these reactivity differences and a guide to the development of future tetrazine coupling partners. The newly disclosed cyclopropenes have kinetic and stability advantages compared to previously reported dienophiles and will be highly useful for applications in organic synthesis, bioorthogonal reactions, and materials science. PMID:24615990

  18. Immunohistochemical localization of hTERT protein in human tissues.

    PubMed

    Yan, Pu; Benhattar, Jean; Seelentag, Walter; Stehle, Jean-Christophe; Bosman, Fred T

    2004-05-01

    Telomerase is a ribonucleoprotein complex mainly composed of a reverse transcriptase catalytic subunit (telomerase reverse transcriptase gene, hTERT) that copies a template region of its RNA subunit to the end of the telomere. For detecting telomerase activity in a tissue specimen the TRAP assay is a relatively sensitive and specific method, but it can be used only on fresh tissue extracts and offers no information at the single cell level. Immunohistochemistry (IHC) allows to detect hTERT protein expression at an individual cell level in human tissues. We have tested commercially available anti-hTERT antibodies in formalin-fixed and paraffin-embedded human tissues by IHC. Only one monoclonal antibody (NCL-hTERT; Novacastra) was sufficiently specific and this was applied to human tissues in which telomerase activity had been shown by TRAP assay and hTERT mRNA expression by RT-PCR. hTERT protein localized diffusely in the nucleoplasm and more intensely in the nucleoli of cancer cells and proliferating normal cells. Mitotic cells showed diffuse staining of the entire cell. Granular cytoplasmic staining was occasionally found in some tumor cells. In telomerase-positive tumors not all the tumor cells showed hTERT immunoreactivity. A significantly heterogeneous hTERT protein expression was observed in human tumor tissues. The hTERT immunostaining in fixed tissues was concordant with telomerase activity and hTERT mRNA expression in corresponding non-fixed samples. Quantitative RT-PCR of microdissected sections showed that hTERT mRNA expression was higher in cells with nuclear expression than in those with cytoplasmic expression. Double staining with the M30 antibody showed that a subpopulation of hTERT-negative cells is apoptotic. We conclude that: (1) hTERT protein can be detected by IHC in fixed human tissues, but the choice of the antibody, tissue processing, and reaction conditions are critical, (2) hTERT protein localizes in the nucleoplasm, more strongly in the nucleolus, and occasionally in the cytoplasm, (3) telomerase-positive tumors show significant heterogeneity of hTERT protein expression, and (4) a subpopulation of hTERT protein negative tumor cells is identified as apoptotic cells. PMID:15138842

  19. 46 CFR Appendix I to Part 150 - Exceptions to the Chart

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... (34) (b) The binary combinations listed below have been determined to be dangerously reactive, based.... Ethyl tert-butyl ether (41) is not compatible with Group 1, Non-oxidizing mineral acids. Ferric...) is not compatible with Group 5 (Caustics). Methyl tert-butyl ether (41) is not compatible with...

  20. STABLE ISOTOPE ANALYSIS OF MTBE TO EVALUATE THE SOURCE OF TBA IN GROUND WATER

    EPA Science Inventory

    Although tert-butyl alcohol (TBA) has not been used as a fuel oxygenate in Orange County, California, the concentrations of TBA in ground water at gasoline spill sites are high compared those of the conventional fuel oxygenate methyl tert-butyl ether (MTBE). In the year 2002, th...

  1. ANAEROBIC DEGRADATION OF MTBE TO TBA IN GROUND WATER AT GASOLINE SPILL SITES IN ORANGE COUNTY, CALIFORNIA

    EPA Science Inventory

    Although tert-Butyl Alcohol (TBA) has not been used as a fuel oxygenate in Orange County, California, the concentrations of TBA in ground water at gasoline spill sites are high compared to the concentrations of the conventional fuel oxygenate Methyl tert-Butyl Ether (MTBE). In t...

  2. Toxic effects of butylated hydroxytoluene on rats.

    PubMed Central

    Saheb, J L; Saheb, S A

    1977-01-01

    A study involving 96 weanling rats of both sexes was conducted to evaluate the effects of the antioxidant butylated hydroxytoluene on the plasma and liver lipid components. Comparative observations in the dietary content of butylated hydroxytoluene in ad libitum and underfed rats. A sex difference in the effects of butylated hydroxytoluene was noted. Butylated hydroxytoluene had a greater deleterious effect on the growth of the male than of the female rat, especially at the 0.5% dietary level (P less than 0.01). At this level, it also increased the relative weight of the liver (P less than 0.01) but had little effect on brain, heart and kidney in both sexes. The enlarged liver showed a marked elevation in the concentration of total lipids and of both total and esterified cholesterol. There were striking increases in the plasma total and esterified cholesterol and phospholipid levels in the butylated hydroxytoluene treated animals buy the triglycerides remained unaffected. The results obtained were more manifest in animals with restricted dietary intake. The changes observed in the lipid components occurred in parallel with the increasing amounts of the antioxidant in the diet. The effect of butylated hydroxytoluene on lipid metabolism is discussed. PMID:861837

  3. Synthesis and spectral characterization of methyl 9(10)-dialkylphosphonostearates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dimethyl, diethyl, and di-n-butyl phosphites were reacted with methyl or ethyl oleates using thermally initiated radical reactions. Reactions were conducted with or without the presence of the lauroyl peroxide initiator. The reactions gave a mixture of isomers with the phosphorous attached at the 9 ...

  4. P. berghei Telomerase Subunit TERT is Essential for Parasite Survival

    PubMed Central

    Religa, Agnieszka A.; Ramesar, Jai; Janse, Chris J.; Scherf, Artur; Waters, Andrew P.

    2014-01-01

    Telomeres define the ends of chromosomes protecting eukaryotic cells from chromosome instability and eventual cell death. The complex regulation of telomeres involves various proteins including telomerase, which is a specialized ribonucleoprotein responsible for telomere maintenance. Telomeres of chromosomes of malaria parasites are kept at a constant length during blood stage proliferation. The 7-bp telomere repeat sequence is universal across different Plasmodium species (GGGTTT/CA), though the average telomere length varies. The catalytic subunit of telomerase, telomerase reverse transcriptase (TERT), is present in all sequenced Plasmodium species and is approximately three times larger than other eukaryotic TERTs. The Plasmodium RNA component of TERT has recently been identified in silico. A strategy to delete the gene encoding TERT via double cross-over (DXO) homologous recombination was undertaken to study the telomerase function in P. berghei. Expression of both TERT and the RNA component (TR) in P. berghei blood stages was analysed by Western blotting and Northern analysis. Average telomere length was measured in several Plasmodium species using Telomere Restriction Fragment (TRF) analysis. TERT and TR were detected in blood stages and an average telomere length of ?950 bp established. Deletion of the tert gene was performed using standard transfection methodologies and we show the presence of tert? mutants in the transfected parasite populations. Cloning of tert- mutants has been attempted multiple times without success. Thorough analysis of the transfected parasite populations and the parasite obtained from extensive parasite cloning from these populations provide evidence for a so called delayed death phenotype as observed in different organisms lacking TERT. The findings indicate that TERT is essential for P. berghei cell survival. The study extends our current knowledge on telomere biology in malaria parasites and validates further investigations to identify telomerase inhibitors to induce parasite cell death. PMID:25275500

  5. Crystal structures of N-tert-butyl-3-(4-fluoro­phenyl)-5-oxo-4-[2-(tri­fluoro­meth­oxy)phen­yl]-2,5-di­hydro­furan-2-carboxamide and 4-(2H-1,3-benzodioxol-5-yl)-N-cyclo­hexyl-5-oxo-3-[4-(tri­fluoro­meth­yl)phen­yl]-2,5-di­hydro­furan-2-carboxamide

    PubMed Central

    Roberts, Sue A.; Martinez-Ariza, Guillermo; Hulme, Christopher

    2015-01-01

    The title compounds, C22H19F4NO4, (I), and C25H22F3NO5, (II), each contain a central nearly planar di­hydro­furan­one ring. The r.m.s. deviation from planarity of these rings is 0.015?Å in (I) and 0.027?Å in (II). The mol­ecules are T-shaped, with the major conformational difference being the O—C—C—O torsion angle [?178.9?(1) in (I) and 37.7?(2)° in (II)]. In the crystal of (I), mol­ecules are linked by N—H?O hydrogen bonds, forming chains along [001] while in (II) mol­ecules are linked by N—H?O hydrogen bonds, forming chains along [010]. In (II), the tri­fluoro­methyl substituent is disordered over two sets of sites, with refined occupancies of 0.751?(3) and 0.249?(3). PMID:25878818

  6. 40 CFR 799.1560 - Diethylene glycol butyl ether and diethylene glycol butyl ether acetate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 32 2011-07-01 2011-07-01 false Diethylene glycol butyl ether and diethylene glycol butyl ether acetate. 799.1560 Section 799.1560 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) IDENTIFICATION OF SPECIFIC CHEMICAL SUBSTANCE AND MIXTURE TESTING...

  7. The DNA methylation inhibitor induces telomere dysfunction and apoptosis of leukemia cells that is attenuated by telomerase over-expression

    PubMed Central

    de Jonge, Nick; Björkholm, Magnus; Xu, Dawei

    2015-01-01

    DNA methyltransferase inhibitors (DNMTIs) such as 5-azacytidine (5-AZA) have been used for treatment of acute myeloid leukemia (AML) and other malignancies. Although inhibiting global/gene-specific DNA methylation is widely accepted as a key mechanism behind DNMTI anti-tumor activity, other mechanisms are likely involved in DNMTI's action. Because telomerase reverse transcriptase (TERT) plays key roles in cancer through telomere elongation and telomere lengthening-independent activities, and TERT has been shown to confer chemo- or radio-resistance to cancer cells, we determine whether DNMTIs affect telomere function and whether TERT/telomerase interferes with their anti-cancer efficacy. We showed that 5-AZA induced DNA damage and telomere dysfunction in AML cell lines by demonstrating the presence of 53-BP1 foci and the co-localization of 53-BP1 foci with telomere signals, respectively. Telomere dysfunction was coupled with diminished TERT expression, shorter telomere and apoptosis in 5-AZA-treated cells. However, 5-AZA treatment did not lead to changes in the methylation status of subtelomere regions. Down-regulation of TERT expression similarly occurred in primary leukemic cells derived from AML patients exposed to 5-AZA. TERT over-expression significantly attenuated 5-AZA-mediated DNA damage, telomere dysfunction and apoptosis of AML cells. Collectively, 5-AZA mediates the down-regulation of TERT expression, and induces telomere dysfunction, which consequently exerts an anti-tumor activity. PMID:25682873

  8. TERT attenuated ER stress-induced cell death.

    PubMed

    Hosoi, Toru; Inoue, Yuki; Nakatsu, Kanako; Matsushima, Naomi; Kiyose, Noriko; Shimamoto, Akira; Tahara, Hidetoshi; Ozawa, Koichiro

    2014-05-01

    Tumor cells are frequently encountered in nutrient-deprived areas, though the mechanisms underlying their survival are unclear. In the present study, we found that depriving cells of glucose caused endoplasmic reticulum stress (ER stress) in a breast cancer cells line, MCF-7, and that specific activation of ER stress increased telomerase reverse transcriptase (TERT) expression. TERT expression would function in counteracting against the stress because over-expression of TERT diminished ER stress-induced cell death. Therefore, the results provide evidence for the underlying mechanisms of tumor progression in stressed conditions, highlighting that ER stress induces TERT expression to withstand environmental stress, a mechanism which we termed the "ER stress-TERT axis". PMID:24746472

  9. Synthesis of 4-butyl-1-substituted-4H-[1,2,4]triazolo[4,3-a]quinazolin-5-ones as new class of H(1)-antihistaminic agents.

    PubMed

    Alagarsamy, V; Shankar, D; Murugesan, S

    2008-03-01

    A series of novel 4-butyl-1-substituted-4H-[1,2,4]triazolo [4,3-a] quinazolin-5-ones were synthesized by the cyclization of 3-butyl-2-hydrazino-3H-quinazolin-4-one with various one carbon donors. The starting material 3-butyl-2-hydrazino-3H-quinazolin-4-one was synthesized from butyl amine by a new innovative route. When tested for their in vivo H(1)-antihistaminic activity on conscious guinea pigs, all the test compounds protected the animals from histamine induced bronchospasm significantly. Compound 4-butyl-1-methyl-4H-[1,2,4]triazolo[4,3-a] quinazolin-5-one (II) emerged as the most active compound of the series and it is equipotent (71.91% protection) when compared to the reference standard chlorpheniramine maleate (71% protection). Compound II show negligible sedation (9%) when compared to chlorpheniramine maleate (30%). PMID:17936567

  10. Crystal structure of [2,6-bis(adamantan-1-yl)-4-tert-butylphenolato-?O]dimethylaluminium(III).

    PubMed

    Wang, Lei; Yang, Li

    2014-10-01

    The title compound, [Al(CH3)2(C30H41O)] is synthesized by the reaction of 2,6-di-adamantyl-4-tert-butyl-phenol with Al(CH3)3 in a nitro-gen atmosphere. In the mol-ecule, the coordination geometry around the Al(III) atom is slightly distorted C2O trigonal (the sum of the bond angles subtended at Al atom being 359.9°), which is rarely reported for organometallic aluminium compounds. The coordination plane is approximately perpendicular to the benzene ring [the dihedral angle = 87.73?(16)°]. There is no inter-molecular hydrogen bonding in the crystal structure. PMID:25484677

  11. Crystal structure of [2,6-bis(adamantan-1-yl)-4-tert-butylphenolato-?O]dimethylaluminium(III)

    PubMed Central

    Wang, Lei; Yang, Li

    2014-01-01

    The title compound, [Al(CH3)2(C30H41O)] is synthesized by the reaction of 2,6-di-adamantyl-4-tert-butyl-phenol with Al(CH3)3 in a nitro­gen atmosphere. In the mol­ecule, the coordination geometry around the AlIII atom is slightly distorted C2O trigonal (the sum of the bond angles subtended at Al atom being 359.9°), which is rarely reported for organometallic aluminium compounds. The coordination plane is approximately perpendicular to the benzene ring [the dihedral angle = 87.73?(16)°]. There is no inter­molecular hydrogen bonding in the crystal structure. PMID:25484677

  12. Accelerated aging of EPDM and butyl elastomers

    SciTech Connect

    Wilson, M.H.

    1996-06-01

    This study was composed of three parts: a post cure study to optimize final properties of an ethylene-propylene-diene (EPDM) formulation, an accelerated aging study to compare the stress relaxation behavior of a butyl and an EPDM elastomer under compression, and a cursory evaluation of a new 70 Shore A EPDM. The optimum postcure for the EPDM was found to be 2 to 4 hours at 182{degrees}C in a vacuum. The EPDM was also shown to have superior aging characteristics compared to the butyl and is recommended for use instead of the butyl material. The physical properties for new 70 Shore A EPDM are satisfactory, and the stress relaxation behavior was only slightly inferior to the other EPDM.

  13. 40 CFR 180.232 - Butylate; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Tolerances § 180.232 Butylate; tolerances for residues. (a) General. Tolerances are established for residues of the herbicide butylate, including its metabolites and degradates, in or on the commodities in the table in this paragraph....

  14. Preparation of microcapsules using the n-butyl half-ester of PVM/MA coacervate system.

    PubMed

    Mortada, S A

    1981-06-01

    The n-butyl half-ester of the polymer polyvinyl methyl ether maleic anhydride was used for the preparation of microcapsules applying a simple encapsulation process which is less difficult to control than other methods of phase separation encapsulation. The data demonstrated that the release of the drug from the microcapsules can be controlled by changing the ratio of the amount of the drug to shell substance. PMID:7279988

  15. Cancer-associated TERT promoter mutations abrogate telomerase silencing

    PubMed Central

    Chiba, Kunitoshi; Johnson, Joshua Z; Vogan, Jacob M; Wagner, Tina; Boyle, John M; Hockemeyer, Dirk

    2015-01-01

    Mutations in the human telomerase reverse transcriptase (TERT) promoter are the most frequent non-coding mutations in cancer, but their molecular mechanism in tumorigenesis has not been established. We used genome editing of human pluripotent stem cells with physiological telomerase expression to elucidate the mechanism by which these mutations contribute to human disease. Surprisingly, telomerase-expressing embryonic stem cells engineered to carry any of the three most frequent TERT promoter mutations showed only a modest increase in TERT transcription with no impact on telomerase activity. However, upon differentiation into somatic cells, which normally silence telomerase, cells with TERT promoter mutations failed to silence TERT expression, resulting in increased telomerase activity and aberrantly long telomeres. Thus, TERT promoter mutations are sufficient to overcome the proliferative barrier imposed by telomere shortening without additional tumor-selected mutations. These data establish that TERT promoter mutations can promote immortalization and tumorigenesis of incipient cancer cells. DOI: http://dx.doi.org/10.7554/eLife.07918.001 PMID:26194807

  16. Methyl Iodide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methyl iodide (MeI, iodomethane, CH3I) was reported as a potential alternative to the stratospheric ozone-depleting fumigant methyl bromide (MeBr) in the mid-1990s (Sims et al., 1995; Ohr et al., 1996). It has since received significant research attention to determine its environmental fate and tran...

  17. 40 CFR 180.232 - Butylate; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Butylate; tolerances for residues. 180... PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.232 Butylate; tolerances for residues. (a) General. Tolerances are established for the herbicide butylate in...

  18. Methyl chloroform

    SciTech Connect

    Wray, T.K.

    1994-04-01

    Methyl chloroform is identified as a Class 1 ozone-depleting substance under Title VI of the CAA Amendments. On Nov. 30, 1993, EPA ordered the phaseout of Class 1 ozone-depleting substances -- chlorofluorocarbons (CFCs), halons, carbon tetrachloride and methyl chloroform -- by Jan. 1, 1996. Methyl chloroform and other Class 1 substances may be used after the dead-line if sources can be found through recycling or existing inventories. Methyl chloroform is listed as a hazardous air pollutant under CAA. It also is a SARA Title III, Sec. 313 compound with a reportable quantity of 1,000 pounds. OSHA and the American Conference of Government Industrial Hygienists have set 350 ppm as the time-weighted average airborne exposure level for methyl chloroform. NIOSH lists its immediately dangerous to life or health'' concentration as 1,000 parts per million. DOT identifies the substance as a hazardous material, Class 6.1 (poison).

  19. An Improved Model for the hTERT Promoter Quadruplex

    PubMed Central

    Chaires, Jonathan B.; Trent, John O.; Gray, Robert D.; Dean, William L.; Buscaglia, Robert; Thomas, Shelia D.; Miller, Donald M.

    2014-01-01

    Mutations occur at four specific sites in the hTERT promoter in >75% of glioblastomas and melanomas, but the mechanism by which the mutations affect gene expression remains unexplained. We report biophysical computational studies that show that the hTERT promoter sequence forms a novel G-quadruplex structure consisting of three contiguous, stacked parallel quadruplexes. The reported hTERT mutations map to the central quadruplex within this structure, and lead to an alteration of its hydrodynamic properties and stability. PMID:25526084

  20. Efficacy of Myricetin as an Antioxidant in Methyl Esters of Soybean Oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The antioxidant activity of myricetin, a natural flavonol found in fruits and vegetables, was determined in soybean oil methyl esters (SME) and compared with alpha-tocopherol and tert-butylhydroquinone (TBHQ) over a 90 day period employing EN 14112, acid value, and kinematic viscosity methods. Myri...

  1. Preparation and release kinetics of hydrochlorothiazide from butyl half-ester of PVM/MA microcapsules.

    PubMed

    Mortada, S A; el Egaky, M A; Motawi, A M; el Khodery, K

    1988-01-01

    This study describes the principle of a simple rapid method for encapsulating hydrochlorothiazide in butyl half-ester of polyvinyl methyl ether-maleic anhydride copolymer to produce a controlled release dosage form. Unplasticized microcapsules and microcapsules plasticized with Tween 80 and castor oil were prepared. Particle size distribution, flow properties and drug content of microcapsules suggested the suitability of the method for encapsulating a wide variety of materials. The in-vitro release rate was studied as a function of core: coat ratio, type and concentration of plasticizer. Various release mechanisms were considered but no single mechanism can explain all the data completely. PMID:3199305

  2. Thermal Polymerization of N-Butyl Acrylate

    NASA Technical Reports Server (NTRS)

    Ingham, J. D.

    1982-01-01

    Simple new polymerization method enables production of n-butyl acrylate polymer of desired high molecular weight, without disadvantages that usually attend more conventional methods. Process, which is hybrid of thermal, solution, and emulsion polymerization methods, involves controlled thermal polymerization of monomer at moderate temperatures without use of catalysts or additives.

  3. Medaka tert produces multiple variants with differential expression during differentiation in vitro and in vivo

    PubMed Central

    Rao, Feng; Wang, Tiansu; Li, Mingyou; Li, Zhendong; Hong, Ni; Zhao, Haobin; Yan, Yan; Lu, Wenqing; Chen, Tiansheng; Wang, Weijia; Lim, Menghuat; Yuan, Yongming; Liu, Ling; Zeng, Lingbing; Wei, Qiwei; Guan, Guijun; Li, Changming; Hong, Yunhan

    2011-01-01

    Embryonic stem (ES) cells have immortality for self-renewal and pluripotency. Differentiated human cells undergo replicative senescence. In human, the telomerase reverse transcriptase (Tert), namely the catalytic subunit of telomerase, exhibits differential expression to regulate telomerase activity governing cellular immortality or senescence, and telomerase activity or tert expression is a routine marker of pluripotent ES cells. Here we have identified the medaka tert gene and determined its expression and telomerase activity in vivo and in vitro. We found that the medaka tert locus produces five variants called terta to terte encoding isoforms TertA to TertE. The longest TertA consists of 1090 amino acid residues and displays a maximum of 34% identity to the human TERT and all the signature motifs of the Tert family. TertB to TertE are novel isoforms and have considerable truncation due to alternative splicing. The terta RNA is ubiquitous in embryos, adult tissues and cell lines, and accompanies ubiquitous telomerase activity in vivo and in vitro as revealed by TRAP assays. The tertb RNA was restricted to the testis, absent in embryos before gastrulation and barely detectable in various cell lines The tertc transcript was absent in undifferentiated ES cells but became evident upon ES cell differentiation, in vivo it was barely detectable in early embryos and became evident when embryogenesis proceeds. Therefore, ubiquitous terta expression correlates with ubiquitous telomerase activity in medaka, and expression of other tert variants appears to delineate cell differentiation in vitro and in vivo. PMID:21547060

  4. CHLORINATED SOLVENT PLUME CONTROL

    EPA Science Inventory

    This lecture will cover recent success in controlling and assessing the treatment of shallow ground water plumes of chlorinated solvents, other halogenated organic compounds, and methyl tert-butyl ether (MTBE).

  5. Phase Selectively Soluble Polystyrene-Supported Organocatalysts 

    E-print Network

    Khamatnurova, Tatyana

    2014-08-10

    Alkane phase selectively soluble poly(4-alkylstyrene) supports have been developed. 4-Methyl-, 4-tert-butyl, 4-dodecyl-, and 4-octadecylstyrene were copolymerized with 5-10 mol % of 4-chloromethylstyrene to afford co- and terpolymers containing...

  6. Single event kinetic modeling of solid acid alkylation of isobutane with butenes over proton-exchanged Y-Zeolites 

    E-print Network

    Martinis Coll, Jorge Maximiliano

    2006-04-12

    numbers, making necessary the inclusion of octane boosters in their formulation. The sustained use of oxygenates such as MTBE (Methyl Tert-Butyl Ether) in RFG is currently under scrutiny because of their high solubility in water. This property makes...

  7. FENTON-DRIVEN CHEMICAL REGENERATION OF MTBE-SPENT GAC

    EPA Science Inventory

    Methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was chemically regenerated utilizing the Fenton mechanism. Two successive GAC regeneration cycles were performed involving iterative adsorption and oxidation processes: MTBE was adsorbed to the GAC, oxidized, r...

  8. (E)-2-[(2-Amino­phen­yl)imino­meth­yl]-4,6-di-tert-butyl­phenol

    PubMed Central

    Ding, Liqin; Lü, Xingqiang; Zhao, Shunsheng; Zhu, Yuqin

    2012-01-01

    In the title compound, C21H28N2O, the dihedral angle between the rings is 35.2?(2)°. A weak intra­molecular O—H?N hydrogen bond is observed between the O—H H atom and the imine N atom. In the crystal, mol­ecules are linked by additional inter­molecular N—H?O hydrogen bonding, resulting in a wave-like chain along the b-axis direction. PMID:23125727

  9. (E)-2-[(2-Amino-phen-yl)imino-meth-yl]-4,6-di-tert-butyl-phenol.

    PubMed

    Ding, Liqin; Lü, Xingqiang; Zhao, Shunsheng; Zhu, Yuqin

    2012-10-01

    In the title compound, C(21)H(28)N(2)O, the dihedral angle between the rings is 35.2?(2)°. A weak intra-molecular O-H?N hydrogen bond is observed between the O-H H atom and the imine N atom. In the crystal, mol-ecules are linked by additional inter-molecular N-H?O hydrogen bonding, resulting in a wave-like chain along the b-axis direction. PMID:23125727

  10. 4-[3-(Benzyl-amino)-2-hy-droxy-prop-yl]-2,6-di-tert-butyl-phenol.

    PubMed

    Asgarova, Ayten R; Allahverdiyev, Mirze A; Khalilov, Ali N; Gurbanov, Atash V; Brito, Iván

    2011-08-01

    In the title compound, C(24)H(35)NO(2), the planes of the two aromatic rings form a dihedral angle of 72.76?(4)°. In the crystal, mol-ecules are linked by O-H?O and O-H?N hydrogen-bond inter-actions, forming an extended two-dimensional framework parallel to the ab plane. PMID:22091054

  11. 4-[3-(Benzyl­amino)-2-hy­droxy­prop­yl]-2,6-di-tert-butyl­phenol

    PubMed Central

    Asgarova, Ayten R.; Allahverdiyev, Mirze A.; Khalilov, Ali. N.; Gurbanov, Atash V.; Brito, Iván

    2011-01-01

    In the title compound, C24H35NO2, the planes of the two aromatic rings form a dihedral angle of 72.76?(4)°. In the crystal, mol­ecules are linked by O—H?O and O—H?N hydrogen-bond inter­actions, forming an extended two-dimensional framework parallel to the ab plane. PMID:22091054

  12. Influence of ultrasonic frequency on Swan band sonoluminescence and sonochemical activity in aqueous tert-butyl alcohol solutions.

    PubMed

    Pflieger, Rachel; Ndiaye, Abdoul Aziz; Chave, Tony; Nikitenko, Sergey I

    2015-01-01

    The multibubble sonoluminescence (MBSL) spectra of t-BuOH aqueous solutions submitted to power ultrasound at 20, 204, 362, and 613 kHz show emissions for the ?? = -1 to ?? = +2 vibrational sequences of C2* Swan system (d(3)?g ? a(3)?u). The ??=+2 emission overlaps with the CH(A-X) emission band. The maximal Swan band emission is observed when the MBSL of water itself is almost completely quenched. In general, MBSL is more intense at high-frequency compared to 20 kHz ultrasound. However, in the presence of Xe, the MBSL of C2* at 20 kHz is so bright that it can be seen by the unaided eye as a blue glow in the close vicinity of the ultrasonic tip. The intensity of the C2* band emission exhibits a maximum vs t-BuOH concentration: 0.1-0.2 M at 20 kHz and (1-8) × 10(-3) M at high-frequency ultrasound. Such a huge difference is attributed to a much smaller bubble size at high ultrasonic frequency or, in other words, to a much higher bubble surface/volume ratio providing more efficient saturation of the bubble interior with t-BuOH vapors and to the fact that high frequency bubbles remain active for many more cycles than 20 kHz ones, thus accumulating more hydrocarbon decomposition products. Simulation of the emission spectra using Specair software demonstrated the absence of thermal equilibrium for C2* radicals (Tv > Tr), where Tv and Tr are the vibrational and the rotational temperature, respectively. In Ar, Tv decreases with increasing t-BuOH concentration reaching a steady value in the concentration domain that corresponds to C2* emission maximum intensity. In the presence of Xe an extremely high Tv is obtained, which is explained by the relatively low ionization potential of Xe providing a higher electron temperature of nonequilibrium plasma generated during bubble collapse. Analysis of the gaseous products of t-BuOH sonolysis reveals a significant sonochemical activity even at high t-BuOH concentration when MBSL is totally quenched, indicating that drastic conditions could be produced also within nonsonoluminescing cavitation bubbles. PMID:25494806

  13. Supporting Information A scalable synthesis of the (S)-4-(tert-butyl)-2-(pyridin-2-yl)-4,5-dihydrooxazole

    E-print Network

    Stoltz, Brian M.

    ) and THF (360 mL) under a positive pressure of nitrogen. The resulting slurry was cooled to 0 ºC in a dry a syringe pump. After the addition was complete, the cooling bath and the thermometer were removed

  14. DNA Methylation

    PubMed Central

    Marinus, M.G.; Løbner-Olesen, A.

    2014-01-01

    The DNA of E. coli contains 19,120 6-methyladenines and 12,045 5-methylcytosines in addition to the four regular bases and these are formed by the postreplicative action of three DNA methyltransferases. The majority of the methylated bases are formed by the Dam and Dcm methyltransferases encoded by the dam (DNA adenine methyltransferase) and dcm (DNA cytosine methyltransferase) genes. Although not essential, Dam methylation is important for strand discrimination during repair of replication errors, controlling the frequency of initiation of chromosome replication at oriC, and regulation of transcription initiation at promoters containing GATC sequences. In contrast, there is no known function for Dcm methylation although Dcm recognition sites constitute sequence motifs for Very Short Patch repair of T/G base mismatches. In certain bacteria (e.g., Vibrio cholerae, Caulobacter crescentus) adenine methylation is essential and in C. crescentus, it is important for temporal gene expression which, in turn, is required for coordinating chromosome initiation, replication and division. In practical terms, Dam and Dcm methylation can inhibit restriction enzyme cleavage; decrease transformation frequency in certain bacteria; decrease the stability of short direct repeats; are necessary for site-directed mutagenesis; and to probe eukaryotic structure and function. PMID:25405210

  15. 40 CFR 704.33 - P-tert-butylbenzoic acid (P-TBBA), p-tert-butyltoluene (P-TBT) and p-tert-butylbenzaldehyde (P-TBB).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... RECORDKEEPING REQUIREMENTS Chemical-Specific Reporting and Recordkeeping Rules § 704.33 P-tert-butylbenzoic acid...) of this section. (i) First standard. A processor of a chemical substance is small if its total annual... the annual processing volume of a particular chemical substance at any individual site owned...

  16. 40 CFR 704.33 - P-tert-butylbenzoic acid (P-TBBA), p-tert-butyltoluene (P-TBT) and p-tert-butylbenzaldehyde (P-TBB).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... RECORDKEEPING REQUIREMENTS Chemical-Specific Reporting and Recordkeeping Rules § 704.33 P-tert-butylbenzoic acid...) of this section. (i) First standard. A processor of a chemical substance is small if its total annual... the annual processing volume of a particular chemical substance at any individual site owned...

  17. Dynamics of MBD2 deposition across methylated DNA regions during malignant transformation of human mammary epithelial cells

    PubMed Central

    Devailly, Guillaume; Grandin, Mélodie; Perriaud, Laury; Mathot, Pauline; Delcros, Jean-Guy; Bidet, Yannick; Morel, Anne-Pierre; Bignon, Jean-Yves; Puisieux, Alain; Mehlen, Patrick; Dante, Robert

    2015-01-01

    DNA methylation is thought to induce transcriptional silencing through the combination of two mechanisms: the repulsion of transcriptional activators unable to bind their target sites when methylated, and the recruitment of transcriptional repressors with specific affinity for methylated DNA. The Methyl CpG Binding Domain proteins MeCP2, MBD1 and MBD2 belong to the latter category. Here, we present MBD2 ChIPseq data obtained from the endogenous MBD2 in an isogenic cellular model of oncogenic transformation of human mammary cells. In immortalized (HMEC-hTERT) or transformed (HMLER) cells, MBD2 was found in a large proportion of methylated regions and associated with transcriptional silencing. A redistribution of MBD2 on methylated DNA occurred during oncogenic transformation, frequently independently of local DNA methylation changes. Genes downregulated during HMEC-hTERT transformation preferentially gained MBD2 on their promoter. Furthermore, depletion of MBD2 induced an upregulation of MBD2-bound genes methylated at their promoter regions, in HMLER cells. Among the 3,160 genes downregulated in transformed cells, 380 genes were methylated at their promoter regions in both cell lines, specifically associated by MBD2 in HMLER cells, and upregulated upon MBD2 depletion in HMLER. The transcriptional MBD2-dependent downregulation occurring during oncogenic transformation was also observed in two additional models of mammary cell transformation. Thus, the dynamics of MBD2 deposition across methylated DNA regions was associated with the oncogenic transformation of human mammary cells. PMID:26007656

  18. TERT gene harbors multiple variants associated with pancreatic cancer susceptibility.

    PubMed

    Campa, Daniele; Rizzato, Cosmeri; Stolzenberg-Solomon, Rachael; Pacetti, Paola; Vodicka, Pavel; Cleary, Sean P; Capurso, Gabriele; Bueno-de-Mesquita, H B As; Werner, Jens; Gazouli, Maria; Butterbach, Katja; Ivanauskas, Audrius; Giese, Nathalia; Petersen, Gloria M; Fogar, Paola; Wang, Zhaoming; Bassi, Claudio; Ryska, Miroslav; Theodoropoulos, George E; Kooperberg, Charles; Li, Donghui; Greenhalf, William; Pasquali, Claudio; Hackert, Thilo; Fuchs, Charles S; Mohelnikova-Duchonova, Beatrice; Sperti, Cosimo; Funel, Niccola; Dieffenbach, Aida Karina; Wareham, Nicholas J; Buring, Julie; Holcátová, Ivana; Costello, Eithne; Zambon, Carlo-Federico; Kupcinskas, Juozas; Risch, Harvey A; Kraft, Peter; Bracci, Paige M; Pezzilli, Raffaele; Olson, Sara H; Sesso, Howard D; Hartge, Patricia; Strobel, Oliver; Ma?ecka-Panas, Ewa; Visvanathan, Kala; Arslan, Alan A; Pedrazzoli, Sergio; Sou?ek, Pavel; Gioffreda, Domenica; Key, Timothy J; Talar-Wojnarowska, Renata; Scarpa, Aldo; Mambrini, Andrea; Jacobs, Eric J; Jamroziak, Krzysztof; Klein, Alison; Tavano, Francesca; Bambi, Franco; Landi, Stefano; Austin, Melissa A; Vodickova, Ludmila; Brenner, Hermann; Chanock, Stephen J; Delle Fave, Gianfranco; Piepoli, Ada; Cantore, Maurizio; Zheng, Wei; Wolpin, Brian M; Amundadottir, Laufey T; Canzian, Federico

    2015-11-01

    A small number of common susceptibility loci have been identified for pancreatic cancer, one of which is marked by rs401681 in the TERT-CLPTM1L gene region on chromosome 5p15.33. Because this region is characterized by low linkage disequilibrium, we sought to identify whether additional single nucleotide polymorphisms (SNPs) could be related to pancreatic cancer risk, independently of rs401681. We performed an in-depth analysis of genetic variability of the telomerase reverse transcriptase (TERT) and the telomerase RNA component (TERC) genes, in 5,550 subjects with pancreatic cancer and 7,585 controls from the PANcreatic Disease ReseArch (PANDoRA) and the PanScan consortia. We identified a significant association between a variant in TERT and pancreatic cancer risk (rs2853677, odds ratio = 0.85; 95% confidence interval = 0.80-0.90, p = 8.3 × 10(-8)). Additional analysis adjusting rs2853677 for rs401681 indicated that the two SNPs are independently associated with pancreatic cancer risk, as suggested by the low linkage disequilibrium between them (r(2) = 0.07, D'?= 0.28). Three additional SNPs in TERT reached statistical significance after correction for multiple testing: rs2736100 (p = 3.0 × 10(-5) ), rs4583925 (p?=?4.0 × 10(-5) ) and rs2735948 (p = 5.0 × 10(-5) ). In conclusion, we confirmed that the TERT locus is associated with pancreatic cancer risk, possibly through several independent variants. PMID:25940397

  19. Methyl methacrylate

    Integrated Risk Information System (IRIS)

    Methyl methacrylate ; CASRN 80 - 62 - 6 ( 03 / 02 / 98 ) Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments f

  20. Methyl parathion

    Integrated Risk Information System (IRIS)

    Methyl parathion ; CASRN 298 - 00 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  1. Methyl acrylate

    Integrated Risk Information System (IRIS)

    Methyl acrylate ; CASRN 96 - 33 - 3 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  2. Methyl chloride

    Integrated Risk Information System (IRIS)

    EPA / 635 / R01 / 003 TOXICOLOGICAL REVIEW OF METHYL CHLORIDE ( CAS No . 74 - 87 - 3 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) June 2001 U.S . Environmental Protection Agency Washington , DC DISCLAIMER This document has been reviewed in accordance with U.

  3. Methyl iodide

    Integrated Risk Information System (IRIS)

    Methyl iodide ; CASRN 74 - 88 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effe

  4. Methyl chlorocarbonate

    Integrated Risk Information System (IRIS)

    Methyl chlorocarbonate ; CASRN 79 - 22 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinog

  5. Methyl isocyanate

    Integrated Risk Information System (IRIS)

    Methyl isocyanate ; CASRN 624 - 83 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  6. Novel Oxidation of Cyclosporin A: Preparation of Cyclosporin Methyl Vinyl Ketone (Cs-MVK)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cyclosporin A (CsA) was converted into cyclosporin methyl vinyl ketone (Cs-MVK) by either a biocatalytic method utilizing 1-hydroxybenzotriazole-mediated laccase oxidation or by a chemical oxidation using t-butyl hydroperoxide and potassium ­periodate as co-oxidants. Cs-MVK is a novel, versatile sy...

  7. Stress-induced premature senescence in BJ and hTERT-BJ1 human foreskin broblasts

    E-print Network

    de Magalhães, João Pedro

    Stress-induced premature senescence in BJ and hTERT-BJ1 human foreskin ¢broblasts Joa telomerase-immortalized human fore- skin ¢broblasts (hTERT-BJ1). We exposed hTERT-BJ1 and parental BJ cells to either UVB or H2O2 subcytotoxic stress(- es). Both cell lines developed biomarkers of replicative senes

  8. 40 CFR 180.232 - Butylate; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Butylate; tolerances for residues. 180... PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.232 Butylate; tolerances for residues. (a) General. Tolerances are established for residues of the...

  9. Global and gene specific DNA methylation changes during zebrafish development

    PubMed Central

    Fang, Xiefan; Corrales, Jone; Thornton, Cammi; Scheffler, Brian E.; Willett, Kristine L.

    2013-01-01

    DNA methylation is dynamic through the life of an organism. Previous studies have primarily focused on DNA methylation changes during very early embryogenesis. In this study, global and gene specific DNA methylation in zebrafish (Danio rerio) embryos, larvae and adult liver were compared. The percent methylation of cytosines was low in 2 to 4.3 hours post fertilization (hpf) zebrafish embryos and was consistently higher in zebrafish older than 6 hpf. Furthermore, quantitative real-time PCR (qPCR) results showed relatively high DNA methyltransferase 1 (dnmt1) and low glycine N-methyltransferase (gnmt) mRNA expression in early embryogenesis. By studying methylation patterns and gene expression of five developmentally important genes, namely vasa, Ras-association domain family member 1 (rassf1), telomerase reverse transcriptase (tert), c-jun and c-myca, we found that the timing of changes in DNA methylation patterns was gene specific, and changes in gene expression were not necessarily correlated with the DNA methylation patterns. PMID:23876386

  10. Synthesis and properties of a highly soluble dihydoxo(tetra-tert-butylphthalocyaninato)antimony(V) complex as a precursor toward water-soluble phthalocyanines.

    PubMed

    Isago, Hiroaki; Miura, Kyoko; Oyama, Youichi

    2008-03-01

    The title complex cation, [Sb(tbpc)(OH)(2)](+) (where tbpc denotes tetra(tert-butyl)phthalocyaninate, C(48)H(48)N(8)(2-)), has been prepared by oxidizing [Sb(tbpc)]I(3) with tert-butyl perbenzoate in CH(2)Cl(2), CHCl(3), o-dichlorobenzene and also without solvent in the range of 20-80 degrees C. This species has been isolated as I(3)(-) salt and characterized by elemental analysis, ESI-MS, FT-IR, optical absorption and emission, and magnetic circular dichroism spectroscopy. This compound is quite well soluble in common polar organic solvents (e.g., CH(2)Cl(2), acetonitrile, acetone) without detectable aggregation at least up to ca. 10(-4)M while much less soluble (e.g., benzene, chloronaphthalene) or insoluble (hexane) in non-polar solvents. Although this compound is insoluble in water, it makes hydrophilic colloids in acetone-water mixtures. The most intense absorption band (Q-band) in a specific solvent red-shifts with an increase in the refractive index of the solvent. However, considerable deviation of the Q-band positions in donor-solvents from linear correlation between the positions and Onsager's solvent polarity function suggests that there are significant specific chemical interactions between the axial hydroxyl groups and the surrounding donor molecules. The low fluorescence quantum yield (ca. 0.01) for [Sb(tbpc)(OH)(2)](+) suggests that the singlet excited state of this species is considerably quenched by the presence of antimony ion in the chromophore. PMID:18164071

  11. Germline TERT promoter mutations are rare in familial melanoma

    E-print Network

    Harland, Mark; Petljak, Mia; Robles-Espinoza, Carla Daniela; Ding, Zhihao; Gruis, Nelleke A.; van Doorn, Remco; Pooley, Karen A.; Dunning, Alison M.; Aoude, Lauren G.; Wadt, Karin A. W.; Gerdes, Anne-Marie; Brown, Kevin M.; Hayward, Nicholas K.; Newton-Bishop, Julia A.; Adams, David J.; Bishop, D. Timothy

    2015-10-03

    -based melanoma cases and 529 controls. Germline lymphocyte telomere length was estimated in carriers. The c.?57 T>G TERT promoter variant was identified in one 7-case family with multiple primaries and early age of onset (earliest, 15 years) but not among...

  12. Blue-colored tert-butylamine clathrate hydrate.

    PubMed

    Tani, Atsushi; Koyama, Satoshi; Urabe, Yusuke; Takato, Kenji; Sugahara, Takeshi; Ohgaki, Kazunari

    2014-11-26

    Clathrate hydrates preserve active species more stably than the other icy materials and investigation of the behavior of the active species elucidates the physicochemical properties of clathrate hydrates like guest-guest interaction. Color of the tert-butylamine clathrate hydrate changes to blue after gamma irradiation and is bleachable with visible light. The electron spin resonance (ESR) spectrum at 120 K mainly consists of a triplet signal of the C-centered radical NH2C(CH3)2CH2• together with a single signal at g = 2.0008. The latter signal disappears after light exposure. These results indicate that both the blue color and the single ESR signal are derived from trapped electrons in the hydrate. They thermally decay around 140-160 K by the first-order reaction, and the activation energy is 27 kJ/mol. Since tert-butylamine molecules can capture protons due to the high proton affinity, electrons may remain in the hydrate without reacting with protons, making the hydrate blue after gamma irradiation. The long-lived trapped electrons in the tert-butylamine hydrate have an advantage to investigate those in icy materials because tert-butylamine hydrate is nonionic and has a tetra-coordinated host water network like crystalline ice without any substitution for water molecules. PMID:25139225

  13. TERT Promoter Mutations and Risk of Recurrence in Meningioma.

    PubMed

    Sahm, Felix; Schrimpf, Daniel; Olar, Adriana; Koelsche, Christian; Reuss, David; Bissel, Juliane; Kratz, Annekathrin; Capper, David; Schefzyk, Sebastian; Hielscher, Thomas; Wang, Qianghu; Sulman, Erik P; Adeberg, Sebastian; Koch, Arend; Okuducu, Ali Fuat; Brehmer, Stefanie; Schittenhelm, Jens; Becker, Albert; Brokinkel, Benjamin; Schmidt, Melissa; Ull, Theresa; Gousias, Konstantinos; Friederike, Almuth; Lamszus, Kessler Katrin; Debus, Jürgen; Mawrin, Christian; Kim, Yoo-Jin; Simon, Matthias; Ketter, Ralf; Paulus, Werner; Aldape, Kenneth D; Herold-Mende, Christel; von Deimling, Andreas

    2016-05-01

    The World Health Organization (WHO) classification and grading system attempts to predict the clinical course of meningiomas based on morphological parameters. However, because of high interobserver variation of some criteria, more reliable prognostic markers are required. Here, we assessed the TERT promoter for mutations in the hotspot regions C228T and C250T in meningioma samples from 252 patients. Mutations were detected in 16 samples (6.4% across the cohort, 1.7%, 5.7%, and 20.0% of WHO grade I, II, and III cases, respectively). Data were analyzed by t test, Fisher's exact test, log-rank test, and Cox proportional hazard model. All statistical tests were two-sided. Within a mean follow-up time in surviving patients of 68.1 months, TERT promoter mutations were statistically significantly associated with shorter time to progression (P < .001). Median time to progression among mutant cases was 10.1 months compared with 179.0 months among wild-type cases. Our results indicate that the inclusion of molecular data (ie, analysis of TERT promoter status) into a histologically and genetically integrated classification and grading system for meningiomas increases prognostic power. Consequently, we propose to incorporate the assessment of TERT promoter status in upcoming grading schemes for meningioma. PMID:26668184

  14. Increased Stability of Nucleolar PinX1 in the Presence of TERT.

    PubMed

    Keo, Ponnarath; Choi, Joong Sub; Bae, Jaeman; Shim, Yhong-Hee; Oh, Bong-Kyeong

    2015-09-30

    PinX1, a nucleolar protein of 328 amino acids, inhibits telomerase activity, which leads to the shortening of telomeres. The C-terminal region of PinX1 is responsible for its nucleolar localization and binding with TERT, a catalytic component of telomerase. A fraction of TERT localizes to the nucleolus, but the role of TERT in the nucleolus is largely unknown. Here, we report a functional connection between PinX1 and TERT regarding PinX1 stability. The C-terminal of PinX1(205-328), a nucleolar fragment, was much more stable than the N-terminal of PinX1(1-204), a nuclear fragment. Interestingly, PinX1 was less stable in TERT-depleted cells and more stable in TERT-myc expressing cells. Stability assays for PinX1 truncation forms showed that both PinX1(1-328) and PinX1(205-328), nucleolar forms, were more rapidly degraded in TERT-depleted cells, while they were more stably maintained in TERT-overexpressing cells, compared to each of the controls. However, PinX1(1-204) was degraded regardless of the TERT status. These results reveal that the stability of PinX1 is maintained in nucleolus in the presence of TERT and suggest a role of TERT in the regulation of PinX1 steady-state levels. PMID:26194824

  15. Novel di-tertiary-butyl phenylhydrazones as dual cyclooxygenase-2/5-lipoxygenase inhibitors: synthesis, COX/LOX inhibition, molecular modeling, and insights into their cytotoxicities.

    PubMed

    Ghatak, Shibnath; Vyas, Alok; Misra, Suniti; O'Brien, Paul; Zambre, Ajit; Fresco, Victor M; Markwald, Roger R; Swamy, K Venkateshwara; Afrasiabi, Zahra; Choudhury, Amitava; Khetmalas, Madhukar; Padhye, Subhash

    2014-01-01

    Although dual inhibition of Cyclooxygenase-2 (COX-2) and 5-Lipoxygenase (5-LOX) enzymes is highly effective than targeting COX or LOX alone, there are only a few reports of examining such compounds in case of colorectal cancers (CRC). In the present work we report that the novel di-tert-butyl phenol-based dual inhibitors DTPSAL, DTPBHZ, DTPINH, and DTPNHZ exhibit significant cytotoxicity against human CRC cell lines. Molecular docking studies revealed a good fit of these compounds in the COX-2 and 5-LOX protein cavities. The inhibitors show significant inhibition of COX-2 and 5-LOX activities and are effective against a panel of human colon cancer cell lines including HCA-7, HT-29, SW480 and intestinal Apc10.1 cells as well as the hyaluronan synthase-2 (Has2) enzyme over-expressing colon cancer cells, through inhibition of the Hyaluronan/CD44v6 cell survival pathway. Western blot analysis and qRT-PCR analyses indicated that the di-tert-butyl phenol-based dual inhibitors reduce the expression of COX-2, 5-LOX, and CD44v6 in human colon cancer HCA-7 cells, while the combination of CD44v6shRNA and DTPSAL has an additional inhibitory effect on CD44v6 mRNA expression. The synergistic inhibitory effect of Celecoxib and Licofelone on CD44v6 mRNA expression suggests that the present dual inhibitors down-regulate cyclooxygenase and lipoxygenase enzymes through CD44v6. The compounds also exhibited enhanced antiproliferative potency compared to standard dual COX/LOX inhibitor, viz. Licofelone. Importantly, the HA/CD44v6 antagonist CD44v6shRNA in combination with synthetic compounds had a sensitizing effect on the cancer cells which enhanced their antiproliferative potency, a finding which is crucial for the anti-proliferative potency of the novel synthetic di-tert-butyl phenol based dual COX-LOX inhibitors in colon cancer cells. PMID:24295787

  16. Cordyceptin induces apoptosis through repressing hTERT expression and inducing extranuclear export of hTERT.

    PubMed

    Jang, Kyung-Jun; Kwon, Gi-Sun; Jeong, Jin-Woo; Kim, Cheol-Hong; Yoon, Hyun-Min; Kim, Gi-Young; Shim, Jung-Hyun; Moon, Sung-Kwon; Kim, Wun-Jae; Choi, Yung Hyun

    2015-03-01

    Cordycepin is an adenosine analog originally extracted from Cordyceps militaris that possesses many pharmacological effects including immune activation and antioxidant and antitumor effects. However, the underlying relationship between apoptosis and telomerase activity in response to cordycepin exposure has not been investigated. In this study, we found that cordycepin-induced apoptosis of human leukemia cells (H937 and THP-1 cells) was associated with inactivation of telomerase and downregulation of human telomerase reverse transcriptase (hTERT) as well as the transcription factors c-Myc and Sp1, which are required for basal transcription from the hTERT gene promoter. Cordycepin also attenuated the activation of phosphoinositide-3-kinase (PI3K)/Akt signaling, thereby reducing phosphorylation and nuclear translocation of hTERT. We further showed that the PI3K inhibitor LY29004 significantly decreased telomerase activity in cordycepin-treated cells and increased cordycepin-induced cell death. These findings demonstrate that cordycepin is cytotoxic to human leukemia cells and suppresses telomerase activity through transcriptional and post-translational suppression of hTERT by inactivating the PI3K/Akt signaling pathway. PMID:25282637

  17. Synthesis of Poly (Butyl Methacrylate/Butyl Acrylate) Highly Absorptive Resin Using Glow Discharge Electrolysis

    NASA Astrophysics Data System (ADS)

    Li, Yan; Yao, Mengqi; Liao, Ruirui; Yang, Wu; Gao, Jinzhang; Ren, Jie

    2014-08-01

    A highly absorptive resin poly (butyl methacrylate (BMA)-co-butyl acrylate (BA)) was prepared by emulsion polymerization, which was initiated by glow discharge electrolysis plasma (GDEP). The effects of discharge voltage, discharge time, monomer ratio and the amounts of cross-linking agent were examined and discussed in detail. The chemical structure of the obtained resin was characterized by means of attenuated total reflectance Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The optimal conditions were obtained as: discharge voltage was 600 V, discharge time was 8 min, the ratios of BMA:BA being 2:1 for chloroform and 3:1 for xylene, with 2% N, N'-methylenebis. Under optimal conditions, the oil absorbency was 70 g/g for chloroform and 46 g/g for xylene. Moreover, the absorptive dynamical behavior of the resulting resin was also investigated.

  18. Bivalent sequential binding of docetaxel to methyl-?-cyclodextrin.

    PubMed

    Mazzaferro, Silvia; Bouchemal, Kawthar; Gallard, Jean-François; Iorga, Bogdan I; Cheron, Monique; Gueutin, Claire; Steinmesse, Claire; Ponchel, Gilles

    2011-09-15

    New docetaxel (Dtx) and cyclodextrin (CD) inclusion complexes having improved apparent water solubility (up to 9.98mgmL(-1)) were obtained from phase solubility diagrams. ?-CD and SBE-?-CD offered only poor solubility enhancements while considerable increases in apparent solubility were obtained with Me-?-CD (20%, w/w) and HP-?-CD (40%, w/w) (9.98mgmL(-1) and 7.43mgmL(-1), respectively). The complexation mechanism between Dtx and Me-?-CD was investigated by circular dichroism spectrometry, two-dimensional (1)H NMR (NOESY) in D(2)O, isothermal titration calorimetry (ITC) and molecular docking calculations. Circular dichroism and NOESY confirmed the existence of non-covalent interactions between Dtx and Me-?-CD and suggested that the tert-butyl group (C(6)-C(9)) and two aromatic groups (C(24)-C(29) and C(30)-C(35)) of Dtx interacted with the Me-?-CD molecules. The combination of ITC results to molecular docking calculations led to the identification of an unconventional sequential binding mechanism between Me-?-CD and Dtx. In this sequential binding, a Me-?-CD molecule first interacted with both tert-butyl and C(30)-C(35) aromatic groups (K(1): 744M(-1)). Then a second Me-?-CD molecule interacted with the C(24)-C(29) aromatic group (K(2): 202M(-1)). The entropy of the first interaction was positive, whereas a negative value of entropy was found for the second interaction. The opposite behavior observed for these two sites was explained by differences in the hydrophobic contact surface and functional group flexibility. PMID:21736931

  19. Recurrent TERT promoter mutations identified in a large-scale study of multiple tumor types are associated with increased TERT expression and telomerase activation

    PubMed Central

    Huang, Dong-Sheng; Wang, Zhaohui; He, Xu-Jun; Diplas, Bill H.; Yang, Rui; Killela, Patrick J.; Liang, Junbo; Meng, Qun; Ye, Zai-Yuan; Wang, Wei; Jiang, Xiao-Ting; Xu, Li; He, Xiang-Lei; Zhao, Zhong-Sheng; Xu, Wen-Juan; Wang, Hui-Ju; Ma, Ying-Yu; Xia, Ying-Jie; Li, Li; Zhang, Ru-Xuan; Jin, Tao; Zhao, Zhong-Kuo; Xu, Ji; Yu, Sheng; Wu, Fang; Wang, Si-Zhen; Jiao, Yu-Chen; Yan, Hai; Tao, Hou-Quan

    2015-01-01

    Background Several somatic mutation hotspots were recently identified in the TERT promoter region in human cancers. Large scale studies of these mutations in multiple tumor types are limited, in particular in Asian populations. This study aimed to: analyze TERT promoter mutations in multiple tumor types in a large Chinese patient cohort, investigate novel tumor types and assess the functional significance of the mutations. Methods TERT promoter mutation status was assessed by Sanger sequencing for 13 different tumor types and 799 tumor tissues from Chinese cancer patients. Thymic epithelial tumors, gastrointestinal leiomyoma, and gastric schwannoma were included, for which the TERT promoter has not been previously sequenced. Functional studies included TERT expression by RT-qPCR, telomerase activity by the TRAP assay, and promoter activity by the luciferase reporter assay. Results TERT promoter mutations were highly frequent in glioblastoma (83.9%), urothelial carcinoma (64.5%), oligodendroglioma (70.0%), medulloblastoma (33.3%), and hepatocellular carcinoma (31.4%). C228T and C250T were the most common mutations. In urothelial carcinoma, several novel rare mutations were identified. TERT promoter mutations were absent in GIST, thymic epithelial tumors, gastrointestinal leiomyoma, gastric schwannoma, cholangiocarcinoma, gastric and pancreatic cancer. TERT promoter mutations highly correlated with upregulated TERT mRNA expression and telomerase activity in adult gliomas. These mutations differentially enhanced the transcriptional activity of the TERT core promoter. Conclusions TERT promoter mutations are frequent in multiple tumor types and have similar distributions in Chinese cancer patients. The functional significance of these mutations reflect the importance to telomere maintenance and hence tumorigenesis, making them potential therapeutic targets. PMID:25843513

  20. Toxic effects of butyl elastomers on aerobic methane oxidation

    NASA Astrophysics Data System (ADS)

    Niemann, Helge; Steinle, Lea I.; Blees, Jan H.; Krause, Stefan; Bussmann, Ingeborg; Lehmann, Moritz F.; Treude, Tina

    2013-04-01

    Large quantities of the potent greenhouse gas methane are liberated into the water column of marine and lacustrine environments where it may be consumed by aerobic methane oxidising bacteria before reaching the atmosphere.The reliable quantification of aerobic methane oxidation (MOx) rates is consequently of paramount importance for estimating methane budgets and to understand the controls on water column methane cycling. A widely used set of methods for measuring MOx rates is based on the incubation of water samples during which the consumption of methane is monitored, for instance with radio-tracer assays. Typically, incubation vessels are sealed with butyl rubber stoppers because these elastomers are essentially impermeable for gases at the relevant time scales. We tested the effect of different stopper materials (unmodified- and halogenated butyl rubber) on MOx activity in environmental samples and in cultures of methane oxidising bacteria. MOx rates in samples sealed with unmodified butyl rubber were > 75% lower compared to parallel incubations with halogenated butyl rubber seals, suggesting inhibiting/toxic effects associated with the use of unmodified butyl elastomers. To further explore the cause of these effects, we analysed aqueous extracts of the different stoppers. Halogenated butyl rubber stoppers appeared to bleed off comparably little amounts of organics. In stark contrast, extracts of unmodified butyl rubber were contaminated with various organic compounds including potential bactericides such as benzyltoluenes, phenylalkanes and benzuothiazoles. We also found tetramethylthiourea, a scavenger of active oxygen species, which may inhibit the MOx pathway.

  1. OXIDATION OF PHENOLIC ANTIOXIDANTS IN A RIVER SYSTEM

    EPA Science Inventory

    The phenolic antioxidants are important commercial organic chemicals. Their environmental fate is of significance because of their abundance and usage patterns. This paper reports on the fates of 2,6-di-tert-butylphenol and the methyl and octadecyl esters of 3-(3,5-di-tert-butyl-...

  2. AVOIDING HYDROLYSIS OF FUEL ETHER OXYGENATES DURING STATIC HEADSPACE ANALYSIS

    EPA Science Inventory

    A headspace autosampler, gas chromatograph and ion trap mass spectrometer (headspace GC/MS) were used for trace analysis of fuel oxygenates and related compounds and aromatics in water. A method has been developed for determination of methyl tert-butyl ether (MTBE), ethyl tert-b...

  3. hTERT mediates norepinephrine-induced Slug expression and ovarian cancer aggressiveness.

    PubMed

    Choi, M J; Cho, K H; Lee, S; Bae, Y J; Jeong, K J; Rha, S Y; Choi, E J; Park, J H; Kim, J M; Lee, J-S; Mills, G B; Lee, H Y

    2015-06-01

    Stress hormones have been implicated in both tumor initiation and progression. Human telomerase reverse transcriptase (hTERT) is overexpressed in cancer cells and associated with malignant tumor progression and poor outcome. We thus sought to determine whether the stress hormone norepinephrine (NE) could induce hTERT expression and subsequently ovarian cancer progression. Unexpectedly, NE induced hTERT transcript and protein expression, and subsequently ovarian cancer cell invasion. Pharmacologic inhibition of ?2-adrenergic receptor 2 and protein kinase A, as well as silencing of hypoxia-inducible factor-1? and c-Myc expression, profoundly attenuated NE-induced hTERT expression. Strikingly, stimulation of the cells with NE or ectopic expression of hTERT induced expression of Slug, ovarian cancer cell epithelial-mesenchymal transition (EMT) and invasion. Silencing of hTERT expression abrogated NE-induced ovarian cancer cell invasion, EMT and Slug expression. In addition, silencing of Slug expression significantly inhibited NE- and hTERT-induced ovarian cancer cell EMT and invasion. Moreover, continuous exposure to NE was sufficient to enhance in vivo hTERT expression and metastasis of ovarian cancer cells to the lung. Finally, we provide evidence that hTERT links Src to Slug expression in NE-induced ovarian cancer EMT and metastasis. We thus demonstrate a novel role of hTERT in stress hormone-induced ovarian cancer aggressiveness through inducing Slug, providing novel biomarkers and potential therapeutic targets for ovarian cancer. PMID:25151968

  4. Effect of 2, 4-di-tert-butylphenol on growth and biofilm formation by an opportunistic fungus Candida albicans.

    PubMed

    Padmavathi, Alwar Ramanujam; Bakkiyaraj, Dhamodharan; Thajuddin, Nooruddin; Pandian, Shunmugiah Karutha

    2015-01-01

    Candida albicans, an opportunistic pathogen, has been known to form hypoxic biofilms on medical devices which in turn confers resistance towards antifungals, resulting in subsequent therapeutic failures. Inclusion of anti-biofilm agents in the control of infections is a topic of current interest in developing potential anti-infectives. The in vitro anti-fungal and anti-biofilm efficacy of 2,4-di-tert-butyl phenol [DTBP] was evaluated in this study, which revealed the potential fungicidal action of DTBP at higher concentrations where fluconazole failed to act completely. DTBP also inhibited the production of hemolysins, phospholipases and secreted aspartyl proteinase which are the crucial virulence factors required for the invasion of C. albicans. Various anti-biofilm assays and morphological observations revealed the efficacy of DTBP in both inhibiting and disrupting biofilms of C. albicans. Inhibition of hyphal development, a key process that aids in initial adhesion of C. albicans, was observed, and this could be a mechanism for the anti-biofilm activity of DTBP. PMID:26299260

  5. Highly recurrent TERT promoter mutations in human melanoma.

    PubMed

    Huang, Franklin W; Hodis, Eran; Xu, Mary Jue; Kryukov, Gregory V; Chin, Lynda; Garraway, Levi A

    2013-02-22

    Systematic sequencing of human cancer genomes has identified many recurrent mutations in the protein-coding regions of genes but rarely in gene regulatory regions. Here, we describe two independent mutations within the core promoter of telomerase reverse transcriptase (TERT), the gene coding for the catalytic subunit of telomerase, which collectively occur in 50 of 70 (71%) melanomas examined. These mutations generate de novo consensus binding motifs for E-twenty-six (ETS) transcription factors, and in reporter assays, the mutations increased transcriptional activity from the TERT promoter by two- to fourfold. Examination of 150 cancer cell lines derived from diverse tumor types revealed the same mutations in 24 cases (16%), with preliminary evidence of elevated frequency in bladder and hepatocellular cancer cells. Thus, somatic mutations in regulatory regions of the genome may represent an important tumorigenic mechanism. PMID:23348506

  6. 76 FR 59906 - Fluazifop-P-butyl; Pesticide Tolerances

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-28

    ...regulation establishes and increases tolerances for residues of fluazifop-P-butyl in or on cotton, gin byproducts; cotton, refined oil; and cotton, undelinted seed. Syngenta Crop Protection requested these tolerances under the Federal...

  7. 21 CFR 172.270 - Sulfated butyl oleate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... edible vegetable oil using 1-butanol. Following sulfation, the reaction mixture is washed with water and neutralized with aqueous sodium or potassium hydroxide. Prior to sulfation, the butyl oleate reaction...

  8. 21 CFR 172.270 - Sulfated butyl oleate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... transesterification of an edible vegetable oil using 1-butanol. Following sulfation, the reaction mixture is washed... oleate reaction mixture meets the following specifications: (1) Not less than 90 percent butyl oleate....

  9. 76 FR 5696 - Fluazifop-P-butyl; Pesticide Tolerances

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-02

    ...FRL-8861-1] Fluazifop-P-butyl; Pesticide Tolerances AGENCY: Environmental Protection...Registration Division (7505P), Office of Pesticide Programs, Environmental Protection Agency...agricultural producer, food manufacturer, or pesticide manufacturer. Potentially affected...

  10. 21 CFR 172.270 - Sulfated butyl oleate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...additive is prepared by sulfation, using concentrated sulfuric acid, of a mixture of butyl esters produced by transesterification of an edible vegetable oil using 1-butanol. Following sulfation, the reaction mixture is washed with...

  11. 21 CFR 172.270 - Sulfated butyl oleate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...additive is prepared by sulfation, using concentrated sulfuric acid, of a mixture of butyl esters produced by transesterification of an edible vegetable oil using 1-butanol. Following sulfation, the reaction mixture is washed with...

  12. 21 CFR 172.270 - Sulfated butyl oleate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...additive is prepared by sulfation, using concentrated sulfuric acid, of a mixture of butyl esters produced by transesterification of an edible vegetable oil using 1-butanol. Following sulfation, the reaction mixture is washed with...

  13. Lipase-Catalyzed Transesterification of Rapeseed Oil for Biodiesel Production with tert-Butanol

    NASA Astrophysics Data System (ADS)

    Jeong, Gwi-Taek; Park, Don-Hee

    Biodiesel is a fatty acid alkyl ester that can be derived from any vegetable oil or animal fat via the process of transesterification. It is a renewable, biodegradable, and nontoxic fuel. In this paper, we have evaluated the efficacy of a transesterification process for rapeseed oil with methanol in the presence of an enzyme and tert-butanol, which is added to ameliorate the negative effects associated with excess methanol. The application of Novozym 435 was determined to catalyze the transesterification process, and a conversion of 76.1% was achieved under selected conditions (reaction temperature 40 °C, methanol/oil molar ratio 3:1, 5% (w/w) Novozym 435 based on the oil weight, water content 1% (w/w), and reaction time of 24h). It has also been determined that rapeseed oil can be converted to fatty acid methyl ester using this system, and the results of this study contribute to the body of basic data relevant to the development of continuous enzymatic processes.

  14. EFFECT OF BTEX ON THE DEGRADATION OF MTBE AND TBA BY MIXED BACTERIAL CONSORTIUM

    EPA Science Inventory

    Methyl tert-butyl ether (MTBE) contamination in groundwater often coexists with benzene, toluene, ethylbenzene, and xylene (BTEX) near the source of the plume. Tertiary butyl alcohol (TBA) is a prevalent intermediate of MTBE degradation. Therefore, there is a significant p...

  15. 40 CFR 414.70 - Applicability; description of the bulk organic chemicals subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Concentrates Decanol Diacetone Alcohol *Dicarboxylic Acids—Salts Diethyl Ether Diethylene Glycol Diethylene... Methacrylate Methyl Tert-Butyl Ether Methylisobutyl Ketone *n-Alkanes n-Butyl Alcohol n-Butylacetate n-Butyraldehyde n-Butyric Acid n-Butyric Anhydride *n-Paraffins n-Propyl Acetate n-Propyl Alcohol...

  16. 40 CFR 414.70 - Applicability; description of the bulk organic chemicals subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Concentrates Decanol Diacetone Alcohol *Dicarboxylic Acids—Salts Diethyl Ether Diethylene Glycol Diethylene... Methacrylate Methyl Tert-Butyl Ether Methylisobutyl Ketone *n-Alkanes n-Butyl Alcohol n-Butylacetate n-Butyraldehyde n-Butyric Acid n-Butyric Anhydride *n-Paraffins n-Propyl Acetate n-Propyl Alcohol...

  17. 40 CFR 414.70 - Applicability; description of the bulk organic chemicals subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Concentrates Decanol Diacetone Alcohol *Dicarboxylic Acids—Salts Diethyl Ether Diethylene Glycol Diethylene... Methacrylate Methyl Tert-Butyl Ether Methylisobutyl Ketone *n-Alkanes n-Butyl Alcohol n-Butylacetate n-Butyraldehyde n-Butyric Acid n-Butyric Anhydride *n-Paraffins n-Propyl Acetate n-Propyl Alcohol...

  18. 40 CFR 414.70 - Applicability; description of the bulk organic chemicals subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Concentrates Decanol Diacetone Alcohol *Dicarboxylic Acids—Salts Diethyl Ether Diethylene Glycol Diethylene... Methacrylate Methyl Tert-Butyl Ether Methylisobutyl Ketone *n-Alkanes n-Butyl Alcohol n-Butylacetate n-Butyraldehyde n-Butyric Acid n-Butyric Anhydride *n-Paraffins n-Propyl Acetate n-Propyl Alcohol...

  19. TERT Promotes Epithelial Proliferation through Transcriptional Control of a Myc- and Wnt-Related Developmental Program

    PubMed Central

    Choi, Jinkuk; Southworth, Lucinda K; Sarin, Kavita Y; Venteicher, Andrew S; Ma, Wenxiu; Chang, Woody; Cheung, Peggie; Jun, Sohee; Artandi, Maja K; Shah, Naman; Kim, Stuart K; Artandi, Steven E

    2008-01-01

    Telomerase serves a critical role in stem cell function and tissue homeostasis. This role depends on its ability to synthesize telomere repeats in a manner dependent on the reverse transcriptase (RT) function of its protein component telomerase RT (TERT), as well as on a novel pathway whose mechanism is poorly understood. Here, we use a TERT mutant lacking RT function (TERTci) to study the mechanism of TERT action in mammalian skin, an ideal tissue for studying progenitor cell biology. We show that TERTci retains the full activities of wild-type TERT in enhancing keratinocyte proliferation in skin and in activating resting hair follicle stem cells, which triggers initiation of a new hair follicle growth phase and promotes hair synthesis. To understand the nature of this RT-independent function for TERT, we studied the genome-wide transcriptional response to acute changes in TERT levels in mouse skin. We find that TERT facilitates activation of progenitor cells in the skin and hair follicle by triggering a rapid change in gene expression that significantly overlaps the program controlling natural hair follicle cycling in wild-type mice. Statistical comparisons to other microarray gene sets using pattern-matching algorithms revealed that the TERT transcriptional response strongly resembles those mediated by Myc and Wnt, two proteins intimately associated with stem cell function and cancer. These data show that TERT controls tissue progenitor cells via transcriptional regulation of a developmental program converging on the Myc and Wnt pathways. PMID:18208333

  20. PTEN and hTERT gene expression and the correlation with human hepatocellular carcinoma.

    PubMed

    Zhou, Xu; Zhu, Huaqiang; Lu, Jun

    2015-04-01

    The aim of this study was to investigate the correlation between tumor suppressor gene phosphatase and tensin homolog (PTEN) expression levels and telomerase activity that mainly depends on telomerase reverse transcriptase (hTERT) in hepatocellular carcinoma (HCC) and paracancerous tissues. Immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) were used to detect the expression of PTEN and hTERT in 58 cases with HCC and the corresponding paracancerous tissues. The correlation between PTEN and hTERT was analyzed. The PTEN mRNA and protein expression was significantly lower in HCC, as compared with the paracancerous tissues (P<0.01), while those of hTERT demonstrated the opposite expression pattern (P<0.01). Additionally, both the PTEN and hTERT protein and mRNA levels demonstrated a significantly negative correlation with one another (P<0.05). In conclusion, PTEN and hTERT have different roles in the development of HCC. A significantly negative correlation between PTEN and hTERT gene expression indicates that hTERT activation and upregulation may be conferred by the loss of PTEN gene expression in HCC. The combined detection of PTEN and hTERT may provide critical clinical evidence for the diagnosis and biological behavior of HCC. PMID:25613699

  1. hTERT promotes the invasion of telomerase-negative tumor cells in vitro.

    PubMed

    Yu, Song-Tao; Chen, Ling; Wang, Hong-Jin; Tang, Xu-Dong; Fang, Dian-Chun; Yang, Shi-Ming

    2009-08-01

    Telomerase activation is a common feature of most types of human cancers. Although several studies have shown that activation of telomerase might participate in the progression of tumors, the mechanism by which telomerase activation causes the invasion and metastasis of tumors remains unclear. In this study, we transfected a vector containing the full-length cDNA of hTERT into a telomerase-negative osteosarcoma cell line U2OS (hTERT/U2OS). Vacant vector-transfected U2OS cells served as a control (EGFP/U2OS). We then compared the biological and vitodynamic changes in these transfected and untransfected U2OS cells. The hTERT protein was detected in hTERT/U2OS cells by Western blot analysis and immunochemistry assay. The telomere length in hTERT/U2OS cells was longer than that in EGFP/U2OS and untransfected U2OS cells. We also found using vacuum micropipette aspiration that hTERT transfection did not only promote the proliferation of hTERT-transfected U2OS cells but also increased the cellular adhesion capacity to the extracellular matrix. Transwell matrigel assay confirmed an increased invasion ability in hTERT/U2OS cells. These results strongly suggest that hTERT transfection promotes the invasion of telomerase-negative cells. Telomerase-mediated telomere maintenance enables these cells to achieve a fully malignant endpoint, including invasion and metastasis. PMID:19578747

  2. Embryolethality of butyl benzyl phthalate in rats

    SciTech Connect

    Ema, N.; Itami, T.; Kawasaki, H. )

    1991-03-15

    The developmental toxicity of butyl benzyl phthalate (BBP) was studied in Wistar rats. Pregnant rats were given BBP at a dosage of 0, 0.25, 0.5, 1.0 or 2.0% in the diet from day 0 to day 20 of pregnancy. Morphological examinations of the fetuses revealed no evidence of teratogenesis. In the 2.0% group, all dams exhibited complete resorption of all the implanted embryos, and their food consumption, body weight gain and adjusted weight gain during pregnancy were markedly lowered. To determine whether the embryolethality was the result of reduced food consumption during pregnancy, a pair-feeding study was performed in which the pregnant rats received the same amount of diet consumed by the 2.0% BBP-treated pregnant rats. The pair-fed and 2.0 % BBP-treated pregnant rats showed significant and comparable reductions in the adjusted weight gain. The number of live fetuses was lowered in the pair-fed group. However, the complete resorption of all the implanted embryos was not found in any of the pair-fed pregnant rats. The data suggest that the embryolethality observed in the 2.0 % BBP-treated pregnant rats is attributable to the effects o dietary BBP.

  3. Facial wound closure with butyl 2-cyanoacrylate.

    PubMed

    Döner, Fehmi; Sari, Ibrahim

    2003-01-01

    Butyl 2-cyanoacrylate (B2-CA), one of the least histotoxic cyanoacrylate derivatives used as a tissue adhesive extensively for facial and plastic, otolaryngological and dental surgery, produces a mild inflammatory response and is biodegradable. In this study, we histopathologically compared B 2-CA to suture on facial wounds of 21 rabbits. Two facial incisions were made on the chins. Left incisions were sutured (control group) and right ones were treated with B 2-CA (experimental group). The animals were divided into 7 groups and were sacrificed on days 1, 2, and 5 and weeks 1, 2, 3, and 4 after surgery. The wound areas were examined histopathologically for the epithelization, inflammation, granulation response, and for foreign body giant cells. Gradation of the histopathological findings yielded no significant difference between the experimental and control groups. Hence, we conclude that B2-CA used on facial wounds shows no more histotoxicity than sutures. Thus, B2-CA could provide an alternative and a possible superior method for closing incisions of facial and plastic surgery. In addition, B2-CA has the advantages of ease of application, immediate homeostasis, and excellent cosmetic results. PMID:15198307

  4. Human telomerase reverse transcriptase (hTERT) promotes cancer invasion by modulating cathepsin D via early growth response (EGR)-1.

    PubMed

    Park, Young-Jin; Kim, Eun Kyoung; Bae, Jung Yoon; Moon, Sook; Kim, Jin

    2016-01-28

    Human telomerase reverse transcriptase (hTERT) contributes to tumor progression as well as maintaining telomere length, however, the mechanism by which hTERT promotes invasiveness is not yet completely understood. This study aims to unravel the precise mechanism through which hTERT promotes cancer invasion. We established an hTERT-overexpressed immortalized cell line (IHOK/hTERT). In orthotopic xenograft models, IHOK/hTERT harbors higher tumorigenicity than IHOK/Control. IHOK/hTERT showed much higher migration and invasion activities compared to IHOK/Control. IHOK/hTERT co-cultured with fibroblasts displayed increased invasion compared to IHOK/hTERT without fibroblasts. We screened for genes that play an important role in intermodulation between cancer cells and fibroblasts using a microarray and identified fibroblast activation protein (FAP). hTERT knockdown showed decreased expression of FAP and early growth response (EGR)-1, one of the transcriptional regulators of FAP in IHOK/hTERT and oral cancer cell line YD10B. Furthermore, EGR-1 knockdown in IHOK/hTERT and YD10B showed reduced invasion and reduced cathepsin D expression compared to Control-siRNA cells. Taken together, this study provides evidence that hTERT overexpression is responsible for the upregulation of the cysteine protease cathepsin D by regulating EGR-1 to activate invasiveness in cancer progression. PMID:26519755

  5. The activating TERT promoter mutation C228T is recurrent in subsets of adrenal tumors

    PubMed Central

    Liu, Tiantian; Brown, Taylor C; Juhlin, C Christofer; Andreasson, Adam; Wang, Na; Bäckdahl, Martin; Healy, James M; Prasad, Manju L; Korah, Reju; Carling, Tobias; Xu, Dawei; Larsson, Catharina

    2014-01-01

    The telomerase reverse transcriptase gene (TERT) encodes the reverse transcriptase component of the telomerase complex, which is essential for telomere stabilization and cell immortalization. Recent studies have demonstrated a transcriptional activation role for the TERT promoter mutations C228T and C250T in many human cancers, as well as a role in aggressive disease with potential clinical applications. Although telomerase activation is known in adrenal tumors, the underlying mechanisms are not established. We assessed C228T and C250T TERT mutations by direct Sanger sequencing in tumors of the adrenal gland, and further evaluated potential associations with clinical parameters and telomerase activation. A total of 199 tumors were evaluated, including 34 adrenocortical carcinomas (ACC), 47 adrenocortical adenomas (ACA), 105 pheochromocytomas (PCC; ten malignant and 95 benign), and 13 abdominal paragangliomas (PGL; nine malignant and four benign). TERT expression levels were determined by quantitative RT-PCR. The C228T mutation was detected in 4/34 ACCs (12%), but not in any ACA (P=0.028). C228T was also observed in one benign PCC and in one metastatic PGL. The C250T mutation was not observed in any case. In the ACC and PGL groups, TERT mutation-positive cases exhibited TERT expression, indicating telomerase activation; however, since expression was also revealed in TERT WT cases, this could denote additional mechanisms of TERT activation. To conclude, the TERT promoter mutation C228T is a recurrent event associated with TERT expression in ACCs, but rarely occurs in PGL and PCC. The involvement of the TERT gene in ACC represents a novel mutated gene in this entity. PMID:24803525

  6. Protective roles of aldo-keto reductase 1B10 and autophagy against toxicity induced by p-quinone metabolites of tert-butylhydroquinone in lung cancer A549 cells.

    PubMed

    Endo, Satoshi; Nishiyama, Ayako; Suyama, Miho; Takemura, Mayuko; Soda, Midori; Chen, Huayue; Tajima, Kazuo; El-Kabbani, Ossama; Bunai, Yasuo; Hara, Akira; Matsunaga, Toshiyuki; Ikari, Akira

    2015-06-01

    tert-Butylhydroquinone (BHQ), an antioxidant used as a food additive, exhibits an anticancer effect at low doses, but is carcinogenic in rodents at high doses. BHQ is metabolized into cytotoxic tert-butylquinone (TBQ), which is further converted to 6-tert-butyl-2,3-epoxy-4-hydroxy-5-cyclohexen-1-one (TBEH) through 6-tert-butyl-2,3-epoxy-4-benzoquinone (TBE). Both TBQ and TBE are cytotoxic, but their toxic mechanisms have not been fully characterized. In this study, we have investigated the toxic mechanisms of TBQ and TBE, and the defense system against the two p-quinones using lung cancer A549 cells. TBQ and TBE, but not BHQ and TBEH, showed cytotoxicity to A549 cells. Neither caspase-3 activation nor an increase in the expression of endoplasmic reticulum stress-associating target genes was observed. TBQ and TBE reacted with reduced glutathione, and significantly decreased the glutathione level in A549 cells, suggesting that the cytotoxicity of the p-quinones is caused by their high electrophilicity reacting with biomolecules. The A549 cells treated with the p-quinones also showed increased levels of autophagic vacuoles and LC3-II protein, which are specific autophagy markers. An autophagy inhibitor, 3-methyladenine (3MA), decreased the LC3-II production by the p-quinones, but enhanced the cytotoxicity induced by TBQ and TBE, suggesting that autophagy contributes to alleviating the p-quinone-triggered cytotoxicity. In addition, the TBE-induced cytotoxicity and autophagy activation in the cells were significantly suppressed by overexpression of aldo-keto reductase (AKR)1B10 that efficiently reduces TBE into TBEH, and were augmented by pretreatment with a potent AKR1B10 inhibitor, C1. The effects of 3MA and C1 on the TBE-induced cytotoxicity were additive. The data provides evidence for the first time that autophagy and AKR1B10 contribute to the defense system against the cytotoxicity caused by the electrophilic p-quinone metabolites of BHQ. PMID:25289770

  7. Molecularly imprinted films of acrylonitrile/methyl methacrylate/acrylic acid terpolymers: influence of methyl methacrylate in the binding performance of L-ephedrine imprinted films.

    PubMed

    Brisbane, Carrie; McCluskey, Adam; Bowyer, Michael; Holdsworth, Clovia I

    2013-05-01

    Molecularly imprinted polymeric films (MIPFs) highly selective to 1R,2S(-)ephedrine (L-ephedrine, EPD) were produced by phase inversion post-polymerization imprinting on poly(acrylonitrile-co-methyl methacrylate-co-acrylic acid) (PAMA) terpolymers. The inclusion of methyl methacrylate (MMA) to the polymer formulation resulted in enhanced EPD selectivity which appears to be dictated by polymer composition to achieve the necessary balance between polymer rigidity and porosity. Substitution of MMA with methyl acrylate, ethyl acrylate and n-butyl acrylate resulted in a loss of EPD selectivity and EPD entrapment within the polymer matrix not observed in PAMA MIPFs. MMA, by virtue of its methyl group, is able to provide the scaffolding and rigidity necessary for stability and preservation of imprinted cavities within the PAMA MIPF leading to high EPD selectivity. PMID:23508285

  8. Functionalization/passivation of porous graphitic carbon with di-tert-amylperoxide

    SciTech Connect

    Jensen, David S.; Gupta, Vipul; Olsen, Rebecca E.; Miller, Alex T.; Davis, Robert C.; Ess, Daniel; Zhu, Zihua; Vail, Michael A.; Dadson, Andrew; Linford, Matthew R.

    2011-11-18

    Porous graphitic carbon (PGC) particles were functionalized/passivated in situ in packed beds at elevated temperature with neat di-tert-amylperoxide (DTAP) in a column oven. The performance of these particles for high performance liquid chromatography (HPLC) was assayed before and after this chemistry with the following analytes: benzene, toluene, ethyl benzene, n-propyl benzene, n-butyl benzene, p-xylene, phenol, 4-methylphenol, phenetole, 3,5-xylenol, and anisole. After the first functionalization/passivation, the retention factors, k, of these compounds decreased by about 5% and the number of theoretical plates (N) increased by ca. 15%. These values of k then remained roughly constant after a second functionalization/ passivation but a further increase in N was noticed. In addition, after each of the reactions, the peak asymmetries decreased by ca. 15%, for a total of ca. 30%. The columns were then subjected twice to methanol at 100 C for 5 h at 1 mL/min. After these stability tests, the values of k remained roughly constant, the number of plates increased, which is favorable, and the asymmetries rose and then declined, where they remained below the initial values for the unfunctionalized columns. Functionalized and unfunctionalized particles were characterized by scanning electron microscopy and BET measurements, which showed no difference between the functionalized and unfunctionalized materials, and X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry (ToF-SIMS), where ToF-SIMS suggested some chemical differences between the functionalized and unfunctionalized materials. In particular ToF-SIMS suggested that the expected five-carbon fragments from DTAP exist at higher concentrations on DTAP-functionalized PGC. First principle calculations on model graphitic surfaces suggest that the first addition of a DTAP radical to the surface proceeds in an approximately isothermal or slightly favorable fashion, but that subsequent DTAP additions are then increasingly thermodynamically favorable. Thus, this analysis suggests that the direct functionalization/passivation of PGC with DTAP is plausible. Chemometric analyses of the chromatographic and ToF-SIMS data are also presented.

  9. Ring Expansion/Homologation-Aldehyde Condensation Cascade using tert-Trihalomethylcarbinols

    PubMed Central

    Falck, J. R.; He, Anyu; Reddy, L. Manmohan; Kundu, Abhijit; Barma, Deb K.; Bandyopadhyay, A.; Kamila, Sukanta; Akella, Radha; Bejot, Romain; Mioskowski, Charles

    2008-01-01

    Treatment of cyclic tert-trihalomethylcarbinols with CrCl2 in THF/HMPA in the presence of aryl or aliphatic aldehydes initiates a cascade sequence of one carbon ring expansion-olefination affording conjugated exo-cyclic ketones. Acyclic tert-trihalomethylcarbinols undergo a comparable cascade of one carbon homologation-olefination. PMID:16986971

  10. Telomerase enzymatic component hTERT shortens long telomeres in human cells

    PubMed Central

    Zheng, Yun-Ling; Zhang, Fan; Sun, Bing; Du, Juan; Sun, Chongkui; Yuan, Jie; Wang, Ying; Tao, Lian; Kota, Krishna; Liu, Xuefeng; Schlegel, Richard; Yang, Qin

    2014-01-01

    Telomere lengths are tightly regulated within a narrow range in normal human cells. Previous studies have extensively focused on how short telomeres are extended and have demonstrated that telomerase plays a central role in elongating short telomeres. However, much about the molecular mechanisms of regulating excessively long telomeres is unknown. In this report, we demonstrated that the telomerase enzymatic component, hTERT, plays a dual role in the regulation of telomere length. It shortens excessively long telomeres and elongates short telomeres simultaneously in one cell, maintaining the optimal telomere length at each chromosomal end for efficient protection. This novel hTERT-mediated telomere-shortening mechanism not only exists in cancer cells, but also in primary human cells. The hTERT-mediated telomere shortening requires hTERT’s enzymatic activity, but the telomerase RNA component, hTR, is not involved in that process. We found that expression of hTERT increases telomeric circular DNA formation, suggesting that telomere homologous recombination is involved in the telomere-shortening process. We further demonstrated that shelterin protein TPP1 interacts with hTERT and recruits hTERT onto the telomeres, suggesting that TPP1 might be involved in regulation of telomere shortening. This study reveals a novel function of hTERT in telomere length regulation and adds a new element to the current molecular model of telomere length maintenance. PMID:24721976

  11. The chicken telomerase reverse transcriptase (chTERT): molecular and cytogenetic characterization with a comparative analysis

    E-print Network

    Delany, Mary E.

    hypothesis of cellular aging proposes that telomere erosion due to a lack of telomerase activity over 0378 longer than in human). Chicken TERT was mapped to chromosome 2q21 near an interstitial telomere site of TERT regulation and function in vertebrates utilizing the telomere clock mechanism to different degrees

  12. Structural Basis for Telomerase Catalytic Subunit TERT Binding to RNA Template and Telomeric DNA

    SciTech Connect

    Mitchell, M.; Gillis, A; Futahashi, M; Fujiwara, H; Skordalakes, E

    2010-01-01

    Telomerase is a specialized DNA polymerase that extends the 3{prime} ends of eukaryotic linear chromosomes, a process required for genomic stability and cell viability. Here we present the crystal structure of the active Tribolium castaneum telomerase catalytic subunit, TERT, bound to an RNA-DNA hairpin designed to resemble the putative RNA-templating region and telomeric DNA. The RNA-DNA hybrid adopts a helical structure, docked in the interior cavity of the TERT ring. Contacts between the RNA template and motifs 2 and B{prime} position the solvent-accessible RNA bases close to the enzyme active site for nucleotide binding and selectivity. Nucleic acid binding induces rigid TERT conformational changes to form a tight catalytic complex. Overall, TERT-RNA template and TERT-telomeric DNA associations are remarkably similar to those observed for retroviral reverse transcriptases, suggesting common mechanistic aspects of DNA replication between the two families of enzymes.

  13. The transcription factor GABP selectively binds and activates the mutant TERT promoter in cancer

    PubMed Central

    Bell, Robert J.A.; Rube, H. Tomas; Kreig, Alex; Mancini, Andrew; Fouse, Shaun D.; Nagarajan, Raman P.; Choi, Serah; Hong, Chibo; He, Daniel; Pekmezci, Melike; Wiencke, John K.; Wrensch, Margaret R.; Chang, Susan M.; Walsh, Kyle M.; Myong, Sua; Song, Jun S.; Costello, Joseph F.

    2015-01-01

    Reactivation of telomerase reverse transcriptase (TERT) expression enables cells to overcome replicative senescence and escape apoptosis, fundamental steps in the initiation of human cancer. Multiple cancer types, including up to 83% of glioblastomas (GBM), harbor highly recurrent TERT promoter mutations of unknown function but specific to two nucleotide positions. We identify the functional consequence of these mutations in GBM to be recruitment of the multimeric GABP transcription factor specifically to the mutant promoter. Allelic recruitment of GABP is consistently observed across four cancer types, highlighting a shared mechanism underlying TERT reactivation. Tandem flanking native ETS motifs critically cooperate with these mutations to activate TERT, likely by facilitating GABP heterotetramer binding. GABP thus directly links TERT promoter mutations to aberrant expression in multiple cancers. PMID:25977370

  14. Assessment of estrogenic potential of di-n-butyl phthalate and butyl benzyl phthalate in vivo.

    PubMed

    Ahmad, Rahish; Verma, Yogendra; Gautam, Anil K; Kumar, Sunil

    2015-12-01

    Phthalate compounds are widely used industrial chemicals; when incorporated into polyvinyl chloride, they are not covalently bound and released into the surrounding media. Some of them have estrogenic potential in vitro but data on in vivo studies are scanty. For the 3-day uterotrophic assay, di-n-butyl phthalate (DBP;10 and 100 mg/kg), butyl benzyl phthalate (BBP; 20 and 200 mg/kg), and diethylstilbestrol (DES, 40 µg/kg, positive control) were administered orally to immature female rats for three consecutive days from postnatal day (PND) 21. For the 20-day pubertal onset assay, DBP (10 and 20 mg/kg), BBP (20 and 200 mg/kg), and DES (6 µg/kg) were administered orally from PND 21 daily for 20 days. In the uterotrophic assay, in groups treated with higher dose of DBP and BBP, the uterine wet weight significantly decreased in the higher dose, and there were minor variations in the ovary wet weight, while the wet weight of these organs increased significantly in DES-treated group. In the 20-day pubertal assay, the weight of uterus and ovary declined significantly and changes in vaginal weight were nonsignificant in DBP- and BBP-treated groups. However, in DES-treated group nonsignificant elevation in vagina weight was observed. All the DES-treated animals showed the vaginal opening (VO) on day 26.17 ± 0.16. However, VO was not observed in any of the animals in control, vehicle control, BBP-, and DBP-treated groups up to PND 42, except in one animal each in vehicle control and DBP (100 mg/kg)-treated groups. The data indicated that both DBP and BBP were unable to induce elevation in the uterine and ovarian weight. While DES treatment can accelerate the growth of uterus and ovary and alter the onset of puberty and estrous cyclicity in prepubertal rats. These suggest that these compounds may not have estrogenic potential in vivo. PMID:23833243

  15. Recycling of gamma irradiated inner tubes in butyl based rubber compounds

    NASA Astrophysics Data System (ADS)

    Karaa?aç, Ba?dagül; ?en, Murat; Deniz, Veli; Güven, Olgun

    2007-12-01

    Recycling of gamma irradiated inner tubes made of butyl rubber in butyl based rubber compounds was studied. Gamma irradiated inner tube wastes and commercial butyl rubber crumbs devulcanized by conventional methods were replaced with butyl rubber up to 15 phr in the compound recipe. The rheological and mechanical properties and carbon black dispersion degree for both types of compounds were measured and then compared to those of virgin butyl rubber compound. It is well known that mechanical properties are deteriorated when rubber crumb is added to the virgin compound. The deterioration in the mechanical properties for the compounds prepared by recycling of irradiated inner tubes at 120 kGy is much lower than the compounds prepared by using commercial butyl crumbs. It has been observed that gamma irradiated used inner tubes were compatible with butyl rubber and could be recycled within butyl based rubber compounds.

  16. Methyl salicylate overdose

    MedlinePLUS

    Methyl salicylate is a wintergreen-scented chemical found in many over-the-counter products, including muscle ache creams. Methyl salicylate overdose occurs when someone accidentally or intentionally takes ...

  17. RFPL3 and CBP synergistically upregulate hTERT activity and promote lung cancer growth.

    PubMed

    Qin, Yu; Chen, Wangbing; Xiao, Yao; Yu, Wendan; Cai, Xin; Dai, Meng; Xu, Tingting; Huang, Wenlin; Guo, Wei; Deng, Wuguo; Wu, Taihua

    2015-09-29

    hTERT is the key component of telomerase and its overactivation contributes to maintaining telomere length and cell immortalization. Previously, we identified RFPL3 as a new transcription activator of hTERT in lung cancers. However, the exact mechanism of RFPL3 in mediating hTERT activation and its associated signal regulatory network remain unclear. In this study, we found that RFPL3 colocalized and interacted directly with CBP in the nucleus of lung cancer cells. Immunohistochemical analysis of tissue microarrays of lung cancers revealed the simultaneous overexpression of both RFPL3 and CBP predicted relatively poor prognosis. Furthermore, we confirmed their synergistic stimulation on hTERT expression and tumor cell growth. The binding of RFPL3 to hTERT promoter was reduced markedly when CBP was knocked down by its specific siRNA or suppressed by its inhibitor in lung cancer cells with stable overexpression of RFPL3. When one of the two proteins RFPL3 and CBP was upregulated or downregulated, whereas the another remains unchanged, hTERT expression and telomerase activity were activated or repressed accordingly. In the meantime, the growth of lung cancer cells was also promoted or attenuated accordingly. Furthermore, we also found that RFPL3 coordinated with CBP to upregulate hTERT through the CBP-induced acetylation of RFPL3 protein and their co-anchoring at hTERT promoter region. Collectively, our results reveal a new mechanism of hTERT regulation in lung cancer cells and suggest the RFPL3/CBP/hTERT signaling pathway may be a new targets for lung cancer treatment. PMID:26318425

  18. Photodetachment and electron reactivity in 1-methyl-1-butyl-pyrrolidinium bis(trifluoromethylsulfonyl)amide

    SciTech Connect

    Molins i Domenech, Francesc; FitzPatrick, Benjamin; Healy, Andrew T.; Blank, David A.

    2012-07-21

    The transient absorption spectrum in the range 500 nm-1000 nm was measured with ultrafast time resolution on a flowing neat, aliphatic, room-temperature ionic liquid following anion photodetachment. In this region the spectrum was shown to be a combination of absorption from the electron and the hole. Spectrally-resolved electron quenching determined a bimodal shape for the hole spectrum in agreement with recent computational predictions on a smaller aliphatic ionic liquid [Margulis et al., J. Am. Chem. Soc. 133, 20186 (2011)]. For time delays beyond 15 ps, spectral evolution qualitatively agrees with recent radiolysis experiments [Wishart et al., Faraday Discuss. 154, 353 (2012)]. However, the shape of the spectrum is different, reflecting the contrast in ionization energy between the two methods. Previously unobserved reactivity of the electron was found with a time constant of 300 fs. The results demonstrate solvent control of the rate coefficient for reaction between the electron and proton, with a rapid decline in the rate within the first picosecond.

  19. REMOVAL OF METHYL TERTIARY BUTYL ETHER (MTBE) FROM GROUNDWATER USING PHOTOCATALYSIS

    EPA Science Inventory

    The potential of photocatalysis was determined for treating MTBE-contaminated drinking water supplies. Two liquid-phase systems, a falling film reactor, and a solar degradation system, are being evaluated. We are also conducting a gas-phase treatment method to simulate an integra...

  20. 1-Butyl-3-Methyl Imidazolium-based Ionic Liquids Explored as Potential Solvents for Lipid Processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to global environmental concerns, there is increasing interest in replacing the volatile solvents currently used to process commodity plant lipids. Room-temperature molten salts are one type of media receiving great attention as a possible replacement of the typical organic solvent. Molten sal...