Science.gov

Sample records for ethylene oxide production

  1. Ethylene production from methionine

    PubMed Central

    Lieberman, M.; Kunishi, A. T.; Mapson, L. W.; Wardale, D. A.

    1965-01-01

    1. A new reaction is described in which ethylene is formed from the Cu+-catalysed breakdown of methionine in phosphate buffer at 30° in air. Some of the other products of the reaction are methionine sulphone, methionine sulphoxide, homocysteic acid, homocystine, acrolein, dimethyl disulphide, methanethiol, ethyl methyl sulphide, methane and ethane. These are considered to be produced in different reaction pathways. 2. Hydrogen peroxide is an intermediate in this reaction and can support ethylene production in the model system in anaerobic atmospheres. Cuprous copper is the active form that catalyses the formation of ethylene from an oxidized intermediate. The initial reaction is probably a Strecker degradation, but the aldehyde product is further degraded to ethylene and other products. 3. Methional (CH3·S·CH2·CH2·CHO) is the most effective producer of ethylene in the model system and appears to be an intermediate in the reaction. 4. The evidence, from both tracer studies and from other precursors of ethylene in the reaction, indicates that ethylene is derived from the −CH2·CH2− group of methionine. PMID:16749150

  2. Radiation and ethylene oxide terminal sterilization experiences with drug eluting stent products.

    PubMed

    Lambert, Byron J; Mendelson, Todd A; Craven, Michael D

    2011-12-01

    Radiation and ethylene oxide terminal sterilization are the two most frequently used processes in the medical device industry to render product within the final sterile barrier package free from viable microorganisms. They are efficacious, safe, and efficient approaches to the manufacture of sterile product. Terminal sterilization is routinely applied to a wide variety of commodity healthcare products (drapes, gowns, etc.) and implantable medical devices (bare metal stents, heart valves, vessel closure devices, etc.) along with products used during implantation procedures (catheters, guidewires, etc.). Terminal sterilization is also routinely used for processing combination products where devices, drugs, and/or biologics are combined on a single product. High patient safety, robust standards, routine process controls, and low-cost manufacturing are appealing aspects of terminal sterilization. As the field of combination products continues to expand and evolve, opportunity exists to expand the application of terminal sterilization to new combination products. Material compatibility challenges must be overcome to realize these opportunities. This article introduces the reader to terminal sterilization concepts, technologies, and the related standards that span different industries (pharmaceutical, medical device, biopharmaceuticals, etc.) and provides guidance on the application of these technologies. Guidance and examples of the application of terminal sterilization are discussed using experiences with drug eluting stents and bioresorbable vascular restoration devices. The examples provide insight into selecting the sterilization method, developing the process around it, and finally qualifying/validating the product in preparation for regulatory approval and commercialization. Future activities, including new sterilization technologies, are briefly discussed. PMID:21887604

  3. Poly(ethylene oxide) functionalization

    DOEpatents

    Pratt, Russell Clayton

    2014-04-08

    A simple procedure is provided by which the hydroxyl termini of poly(ethylene oxide) can be appended with functional groups to a useful extent by reaction and precipitation. The polymer is dissolved in warmed toluene, treated with an excess of organic base and somewhat less of an excess of a reactive acylating reagent, reacted for several hours, then precipitated in isopropanol so that the product can be isolated as a solid, and salt byproducts are washed away. This procedure enables functionalization of the polymer while not requiring laborious purification steps such as solvent-solvent extraction or dialysis to remove undesirable side products.

  4. Final Technical Report - High-Performance, Oxide-Dispersion-Strengthened Tubes for Production of Ethylene adn Other Industrial Chemicals

    SciTech Connect

    McKimpson, Marvin G.

    2006-04-06

    This project was undertaken by Michigan Technological University and Special Metals Corporation to develop creep-resistant, coking-resistant oxide-dispersion-strengthened (ODS) tubes for use in industrial-scale ethylene pyrolysis and steam methane reforming operations. Ethylene pyrolysis tubes are exposed to some of the most severe service conditions for metallic materials found anywhere in the chemical process industries, including elevated temperatures, oxidizing atmospheres and high carbon potentials. During service, hard deposits of carbon (coke) build up on the inner wall of the tube, reducing heat transfer and restricting the flow of the hydrocarbon feedstocks. About every 20 to 60 days, the reactor must be taken off-line and decoked by burning out the accumulated carbon. This decoking costs on the order of $9 million per year per ethylene plant, accelerates tube degradation, and requires that tubes be replaced about every 5 years. The technology developed under this program seeks to reduce the energy and economic cost of coking by creating novel bimetallic tubes offering a combination of improved coking resistance, creep resistance and fabricability not available in current single-alloy tubes. The inner core of this tube consists of Incoloy(R) MA956, a commercial ferritic Fe-Cr-Al alloy offering a 50% reduction in coke buildup combined with improved carburization resistance. The outer sheath consists of a new material - oxide dispersion strengthened (ODS) Alloy 803(R) developed under the program. This new alloy retains the good fireside environmental resistance of Alloy 803, a commercial wrought alloy currently used for ethylene production, and provides an austenitic casing to alleviate the inherently-limited fabricability of the ferritic Incoloy(R) MA956 core. To provide mechanical compatibility between the two alloys and maximize creep resistance of the bimetallic tube, both the inner Incoloy(R) MA956 and the outer ODS Alloy 803 are oxide dispersion

  5. Portable Ethylene Oxide Sterilization Chamber

    PubMed Central

    Songer, J. R.; Mathis, R. G.

    1969-01-01

    A portable ethylene oxide sterilization chamber was designed, constructed, and tested for use in the sterilization of embolectomy catheters. The unit can accommodate catheters up to 40 inches (101.6 cm) in length and can be operated for less than 4 cents per cycle. A constant concentration of 500 mg of ethylene oxide per liter of space and holding periods of 4 and 6 hr at 43 and 22 C, respectively, were adequate when tested with B. subtilis spores. The estimated cost of construction was $165.00. If temperature control is unnecessary, the cost is approximately $80.00. Images PMID:4977644

  6. Ethylene oxide sterilisation--is it safe?

    PubMed Central

    Gillespie, E H; Jackson, J M; Owen, G R

    1979-01-01

    Tests show that ethylene oxide penetrates and can sterilise long narrow tubes in a hospital ethylene oxide steriliser. Residual ethylene oxide levels in plastic tubing after sterilisation have been estimated. Although initially the levels were very high, storage for four days at room temperature reduced them to a safe level. If adequate controls of the sterilising process and storage are carried out, sterilisation by ethylene oxide is considered to be safe for new plastics and clean equipment. Images Figure PMID:512032

  7. 49 CFR 173.323 - Ethylene oxide.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Ethylene oxide. 173.323 Section 173.323... SHIPMENTS AND PACKAGINGS Gases; Preparation and Packaging § 173.323 Ethylene oxide. (a) For packaging ethylene oxide in non-bulk packagings, silver mercury or any of its alloys or copper may not be used in...

  8. Ethylene oxide and acetaldehyde in hot cores

    NASA Astrophysics Data System (ADS)

    Occhiogrosso, A.; Vasyunin, A.; Herbst, E.; Viti, S.; Ward, M. D.; Price, S. D.; Brown, W. A.

    2014-04-01

    Context. Ethylene oxide (c-C2H4O), and its isomer acetaldehyde (CH3CHO), are important complex organic molecules because of their potential role in the formation of amino acids. The discovery of ethylene oxide in hot cores suggests the presence of ring-shaped molecules with more than 3 carbon atoms such as furan (c-C4H4O), to which ribose, the sugar found in DNA, is closely related. Aims: Despite the fact that acetaldehyde is ubiquitous in the interstellar medium, ethylene oxide has not yet been detected in cold sources. We aim to understand the chemistry of the formation and loss of ethylene oxide in hot and cold interstellar objects (i) by including in a revised gas-grain network some recent experimental results on grain surfaces and (ii) by comparison with the chemical behaviour of its isomer, acetaldehyde. Methods: We introduce a complete chemical network for ethylene oxide using a revised gas-grain chemical model. We test the code for the case of a hot core. The model allows us to predict the gaseous and solid ethylene oxide abundances during a cooling-down phase prior to star formation and during the subsequent warm-up phase. We can therefore predict at what temperatures ethylene oxide forms on grain surfaces and at what temperature it starts to desorb into the gas phase. Results: The model reproduces the observed gaseous abundances of ethylene oxide and acetaldehyde towards high-mass star-forming regions. In addition, our results show that ethylene oxide may be present in outer and cooler regions of hot cores where its isomer has already been detected. Our new results are compared with previous results, which focused on the formation of ethylene oxide only. Conclusions: Despite their different chemical structures, the chemistry of ethylene oxide is coupled to that of acetaldehyde, suggesting that acetaldehyde may be used as a tracer for ethylene oxide towards cold cores.

  9. Kinetics of ethylene oxide desorption from sterilized materials.

    PubMed

    Mendes, Gisela C; Brandão, Teresa R S; Silva, Cristina L M

    2013-01-01

    Ethylene oxide gas is commonly used to sterilize medical devices, and concerns about using this agent on biological systems are well-established. Medical devices sterilized by ethylene oxide must be properly aerated to remove residual gas and by-products. In this work, kinetics of ethylene oxide desorption from different sterilized materials were studied in a range of aeration temperatures. The experimental data were well-described by a Fickian diffusion mass transfer behavior, and diffusivities were estimated for two textile and two polymeric materials within the temperature range of 1.5 to 59.0 degrees C. The results will allow predictions of ethylene oxide desorption, which is a key step for the design of sterilization/aeration processes, contributing to an efficient removal of residual ethylene oxide content. PMID:23513954

  10. Storage stability of Bacillus subtilis ethylene oxide biological indicators.

    PubMed Central

    Reich, R R

    1980-01-01

    Bacillus subtilis biological indicators, stored at ambient and freezer conditions for 24 months, demonstrated no statistical difference in ethylene oxide resistance and spore viability from initial production levels. PMID:6766701

  11. 29 CFR 1910.1047 - Ethylene oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 6 2014-07-01 2013-07-01 true Ethylene oxide. 1910.1047 Section 1910.1047 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS (CONTINUED) Toxic and Hazardous Substances § 1910.1047 Ethylene oxide. (a) Scope and...

  12. Individual Shrink Wrapping of Zucchini Fruit Improves Postharvest Chilling Tolerance Associated with a Reduction in Ethylene Production and Oxidative Stress Metabolites

    PubMed Central

    Megías, Zoraida; Martínez, Cecilia; Manzano, Susana; García, Alicia; Rebolloso-Fuentes, María del Mar; Garrido, Dolores; Valenzuela, Juan Luis; Jamilena, Manuel

    2015-01-01

    We have studied the effect of individual shrink wrapping (ISW) on the postharvest performance of refrigerated fruit from two zucchini cultivars that differ in their sensitivity to cold storage: Sinatra (more sensitive) and Natura (more tolerant). The fruit was individually shrink wrapped before storing at 4°C for 0, 7 and 14 days. Quality parameters, ethylene and CO2 productions, ethylene gene expression, and oxidative stress metabolites were assessed in shrink wrapped and non-wrapped fruit after conditioning the fruit for 6 hours at 20°C. ISW decreased significantly the postharvest deterioration of chilled zucchini in both cultivars. Weight loss was reduced to less than 1%, pitting symptoms were completely absent in ISW fruit at 7 days, and were less than 25% those of control fruits at 14 days of cold storage, and firmness loss was significantly reduced in the cultivar Sinatra. These enhancements in quality of ISW fruit were associated with a significant reduction in cold-induced ethylene production, in the respiration rate, and in the level of oxidative stress metabolites such as hydrogen peroxide and malonyldialdehyde (MDA). A detailed expression analysis of ethylene biosynthesis, perception and signaling genes demonstrated a downregulation of CpACS1 and CpACO1 genes in response to ISW, two genes that are upregulated by cold storage. However, the expression patterns of six other ethylene biosynthesis genes (CpACS2 to CpACS7) and five ethylene signal transduction pathway genes (CpCTR1, CpETR1, CpERS1, CpEIN3.1 and CpEN3.2), suggest that they do not play a major role in response to cold storage and ISW packaging. In conclusion, ISW zucchini packaging resulted in improved tolerance to chilling concomitantly with a reduction in oxidative stress, respiration rate and ethylene production, as well as in the expression of ethylene biosynthesis genes, but not of those involved in ethylene perception and sensitivity. PMID:26177024

  13. Individual Shrink Wrapping of Zucchini Fruit Improves Postharvest Chilling Tolerance Associated with a Reduction in Ethylene Production and Oxidative Stress Metabolites.

    PubMed

    Megías, Zoraida; Martínez, Cecilia; Manzano, Susana; García, Alicia; Rebolloso-Fuentes, María Del Mar; Garrido, Dolores; Valenzuela, Juan Luis; Jamilena, Manuel

    2015-01-01

    We have studied the effect of individual shrink wrapping (ISW) on the postharvest performance of refrigerated fruit from two zucchini cultivars that differ in their sensitivity to cold storage: Sinatra (more sensitive) and Natura (more tolerant). The fruit was individually shrink wrapped before storing at 4°C for 0, 7 and 14 days. Quality parameters, ethylene and CO2 productions, ethylene gene expression, and oxidative stress metabolites were assessed in shrink wrapped and non-wrapped fruit after conditioning the fruit for 6 hours at 20°C. ISW decreased significantly the postharvest deterioration of chilled zucchini in both cultivars. Weight loss was reduced to less than 1%, pitting symptoms were completely absent in ISW fruit at 7 days, and were less than 25% those of control fruits at 14 days of cold storage, and firmness loss was significantly reduced in the cultivar Sinatra. These enhancements in quality of ISW fruit were associated with a significant reduction in cold-induced ethylene production, in the respiration rate, and in the level of oxidative stress metabolites such as hydrogen peroxide and malonyldialdehyde (MDA). A detailed expression analysis of ethylene biosynthesis, perception and signaling genes demonstrated a downregulation of CpACS1 and CpACO1 genes in response to ISW, two genes that are upregulated by cold storage. However, the expression patterns of six other ethylene biosynthesis genes (CpACS2 to CpACS7) and five ethylene signal transduction pathway genes (CpCTR1, CpETR1, CpERS1, CpEIN3.1 and CpEN3.2), suggest that they do not play a major role in response to cold storage and ISW packaging. In conclusion, ISW zucchini packaging resulted in improved tolerance to chilling concomitantly with a reduction in oxidative stress, respiration rate and ethylene production, as well as in the expression of ethylene biosynthesis genes, but not of those involved in ethylene perception and sensitivity. PMID:26177024

  14. [A chromatographic and surface-activity analysis of the fractions of Rokopols, block copolymers of propylene oxide and ethylene oxide separated from the technical product].

    PubMed

    Zgoda, Marian Mikołaj; Nachajski, Michał Jakub

    2008-01-01

    A metod of refininig technical Rokopols, products of copolymerization of ethylene oxide and propylene oxide of 30p160, 30p27 and 30p10 type was developed. The course of the relation between R(f)(R(m)) and the number of oxyethylene segments n(TE) in the molecule of the homological series ofpolyethyleneglycols (PEG) was used to examine the content of n(TE) in the refined fractions of Rokopols. For the aqueous solutions of Rokopols weight-average molecular mass M(w) was calculated and the surface tension coefficient gamma25 was determined on the basis of the stalgmometric method. The value of the critical micellar concentration (cmc) and the thermodynamic potential for micelle formation (DeltaG(m)(0)), which facilitates the assessment of the solubilizing abilities of the investigated class of copolymers, were estimated. PMID:19137973

  15. Novel membrane technology for green ethylene production.

    SciTech Connect

    Balachandran, U.; Lee, T. H.; Dorris, S. E.; Udovich, C. A.; Scouten, C. G.; Marshall, C. L.

    2008-01-01

    reactions and prolong membrane life. With the Argonne approach, oxygen does not contact the ethane/ethylene stream, so oxidation products are not formed. Consequently, higher selectivity to ethylene and fewer by-products can be achieved. Some benefits are: (1) Simplifies overall product purification and processing schemes; (2) Results in greater energy efficiency; (3) Completely eliminates greenhouse gases from the reactor section; and (4) Lowers the cost of the 'back end' purification train, which accounts for about 70% of the capital cost of a conventional ethylene production unit.

  16. Understanding the Impact of Poly(ethylene oxide) on the Assembly of Lignin in Solution toward Improved Carbon Fiber Production.

    PubMed

    Imel, Adam E; Naskar, Amit K; Dadmun, Mark D

    2016-02-10

    Carbon fiber produced from lignin has recently become an industrial scalable product with applications ranging from thermal insulation to reinforcing automobile bodies. Previous research has shown that mixing 1-2 wt %, of poly(ethylene oxide) (PEO) with the lignin before fiber formation can enhance the properties of the final carbon fibers. The research reported here determines the impact of adding PEO to a lignin solution on its assembly, focusing on the role of the lignin structure on this assembly process. Results indicate the addition of PEO anisotropically directs the self-assembly of the hardwood and softwood lignin by lengthening the cylindrical building blocks that make up the larger global aggregates. On the other hand, results from an annual lignin exhibit a shapeless, more complex structure with a unique dependence on the PEO loading. These results are consistent with improved carbon fibers from solutions of lignin that include PEO, as the local ordering and directed assembly will inhibit the formation of defects during the carbon fiber fabrication process. PMID:26756927

  17. Health Assessment Document for Ethylene Oxide

    EPA Science Inventory

    The largest single use of ethylene oxide is as an intermediate in the synthesis of ethylene glycol. However, small amounts of this epoxide are used as a sterilant or pesticide in commodities, pharmaceuticals, medical devices, tobacco, and other items, representing a considerable ...

  18. 49 CFR 173.323 - Ethylene oxide.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... and gaskets must be constructed of materials which are compatible with ethylene oxide and do not lower... the lading. (h) Neoprene, natural rubber and asbestos gaskets are prohibited. All packing and...

  19. 49 CFR 173.323 - Ethylene oxide.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... and gaskets must be constructed of materials which are compatible with ethylene oxide and do not lower... the lading. (h) Neoprene, natural rubber and asbestos gaskets are prohibited. All packing and...

  20. 21 CFR 172.770 - Ethylene oxide polymer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene oxide polymer. 172.770 Section 172.770... CONSUMPTION Other Specific Usage Additives § 172.770 Ethylene oxide polymer. The polymer of ethylene oxide may... conditions. (a) It is the polymer of ethylene oxide having a minimum viscosity of 1,500 centipoises in a...

  1. 21 CFR 172.770 - Ethylene oxide polymer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ethylene oxide polymer. 172.770 Section 172.770... CONSUMPTION Other Specific Usage Additives § 172.770 Ethylene oxide polymer. The polymer of ethylene oxide may... conditions. (a) It is the polymer of ethylene oxide having a minimum viscosity of 1,500 centipoises in a...

  2. High ethylene to ethane processes for oxidative coupling

    DOEpatents

    Chafin, Richard B.; Warren, Barbara K.

    1991-01-01

    Oxidative coupling of lower alkane to higher hydrocarbon is conducted using catalyst comprising barium and/or strontium component and a metal oxide combustion promoter in the presence of vapor phase halogen component. High ethylene to ethane mole ratios in the product can be obtained over extended operating periods.

  3. High ethylene to ethane processes for oxidative coupling

    DOEpatents

    Chafin, R.B.; Warren, B.K.

    1991-12-17

    Oxidative coupling of lower alkane to higher hydrocarbon is conducted using a catalyst comprising barium and/or strontium component and a metal oxide combustion promoter in the presence of vapor phase halogen component. High ethylene to ethane mole ratios in the product can be obtained over extended operating periods.

  4. Biocatalytic conversion of ethylene to ethylene oxide using an engineered toluene monooxygenase

    SciTech Connect

    Carlin, DA; Bertolani, SJ; Siegel, JB

    2015-01-01

    Mutants of toluene o-xylene monooxygenase are demonstrated to oxidize ethylene to ethylene oxide in vivo at yields of >99%. The best mutant increases ethylene oxidation activity by >5500-fold relative to the native enzyme. This is the first report of a recombinant enzyme capable of carrying out this industrially significant chemical conversion.

  5. 29 CFR 1915.1047 - Ethylene oxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Ethylene oxide. 1915.1047 Section 1915.1047 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD EMPLOYMENT Toxic and Hazardous...

  6. CADMIUM-INDUCED ETHYLENE PRODUCTION IN BEAN PLANTS

    EPA Science Inventory

    Studies were conducted to (1) compare stress ethylene production from roots and shoots (2) determine the association between stress ethylene production and tissue Cd levels; and (3) investigate the time course of stress ethylene production following the rhizosphere application of...

  7. 21 CFR 880.6860 - Ethylene oxide gas sterilizer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ethylene oxide gas sterilizer. 880.6860 Section 880.6860 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Miscellaneous Devices § 880.6860 Ethylene oxide gas sterilizer. (a) Identification. An ethylene gas...

  8. 21 CFR 880.6860 - Ethylene oxide gas sterilizer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ethylene oxide gas sterilizer. 880.6860 Section 880.6860 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Miscellaneous Devices § 880.6860 Ethylene oxide gas sterilizer. (a) Identification. An ethylene gas...

  9. 21 CFR 880.6860 - Ethylene oxide gas sterilizer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ethylene oxide gas sterilizer. 880.6860 Section 880.6860 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Miscellaneous Devices § 880.6860 Ethylene oxide gas sterilizer. (a) Identification. An ethylene gas...

  10. Gas dynamics of ethylene oxide during sterilization

    NASA Astrophysics Data System (ADS)

    Zhu, Z.; Matthews, I. P.; Wang, C.

    1999-07-01

    This article reports a case study of the dynamics of ethylene oxide gas during sterilization using a microwave spectrometer. A diffusion equation is used to describe the processes of gas penetration, gas sorption, and chemical reactions. The three processes, although mathematically related, may be solved separately under simplified assumptions. This permits the prediction of gas penetration and sorption as well as the effect of chemical reactions upon the gas concentration for loads of differing dimensions and densities.

  11. CHROMATOGRAPHIC METHODS FOR ANALYSIS OF ETHYLENE OXIDE IN EMISSIONS FROM STATIONARY SOURCES

    EPA Science Inventory

    Chromatographic methods of analysis with FID detection were investigated for quantitation of ethylene oxide in emissions from production-plants and commercial sterilizers. olumn with a stationary phase of 3% Carbowax 20M on 80/lOO Chromsorb 101 was used to separate ethylene oxide...

  12. Microbiological aspects of ethylene oxide sterilization. II. Microbial resistance to ethylene oxide.

    PubMed

    Kereluk, K; Gammon, R A; Lloyd, R S

    1970-01-01

    The death rate kinetics of several sporeforming and nonsporeforming microorganisms, including radiation-resistant cocci, were determined by exposing them to a mixture of ethylene oxide and dichlorodifluoromethane (500 mg of ethylene oxide per liter, 30 to 50% relative humidity, and 54.4 C). Spore survivor curves obtained from tests of inoculated and exposed hygroscopic and nonhygroscopic carriers showed that the spores of Bacillus subtilis var. niger are more resistant to ethylene oxide than are spores of Clostridium sporogenes, B. stearothermophilus, and B. pumilus. The decimal reduction times (expressed as D values at 54.4 C-500 mg of ethylene oxide per liter) obtained under the test conditions for B. subtilis var. niger spores on hygroscopic and nonhygroscopic carriers exceeded the values obtained for the other organisms considered, both sporeformers and nonsporeformers. The decimal reduction times for the vegetative cells of the radiation-resistant organisms (Micrococcus radiodurans and two strains of Streptococcus faecalis) and the ATCC strain of S. faecalis demonstrated comparable resistance to ethylene oxide with the spores of C. sporogenes, B. stearothermophilus, and B. pumilus, but not those of B. subtilis var. niger. PMID:5415211

  13. Ethylene-forming enzyme and bioethylene production

    PubMed Central

    2014-01-01

    Worldwide, ethylene is the most produced organic compound. It serves as a building block for a wide variety of plastics, textiles, and chemicals, and a process has been developed for its conversion into liquid transportation fuels. Currently, commercial ethylene production involves steam cracking of fossil fuels, and is the highest CO2-emitting process in the chemical industry. Therefore, there is great interest in developing technology for ethylene production from renewable resources including CO2 and biomass. Ethylene is produced naturally by plants and some microbes that live with plants. One of the metabolic pathways used by microbes is via an ethylene-forming enzyme (EFE), which uses α-ketoglutarate and arginine as substrates. EFE is a promising biotechnology target because the expression of a single gene is sufficient for ethylene production in the absence of toxic intermediates. Here we present the first comprehensive review and analysis of EFE, including its discovery, sequence diversity, reaction mechanism, predicted involvement in diverse metabolic modes, heterologous expression, and requirements for harvesting of bioethylene. A number of knowledge gaps and factors that limit ethylene productivity are identified, as well as strategies that could guide future research directions. PMID:24589138

  14. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... with a ventilation system designed to circulate and exchange the air in the cabinet to shorten the...

  15. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... with a ventilation system designed to circulate and exchange the air in the cabinet to shorten the...

  16. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... with a ventilation system designed to circulate and exchange the air in the cabinet to shorten the...

  17. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... with a ventilation system designed to circulate and exchange the air in the cabinet to shorten the...

  18. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... with a ventilation system designed to circulate and exchange the air in the cabinet to shorten the...

  19. A New Interstellar Cyclic Molecule, Ethylene Oxide

    NASA Astrophysics Data System (ADS)

    Dickens, J. E.; Irvine, W. M.; Ohishi, M.; Ikeda, M.; Ishikawa, S.; Nummelin, A.; Hjalmarson, A.

    1997-12-01

    Ethylene oxide (c-C2H4O) is only the fourth known ring molecule identified in the interstellar medium, detected in the Galactic Center cloud SgrB2(N) by Dickens et al. (1997). It is the higher energy isomer of both the more familiar interstellar species acetaldehyde (CH3CHO) and the as yet undetected molecule vinyl alcohol (CH2CHOH). Dickens et al. (1997) reported a c-C2H4O molecular column density about an order of magnitude less than that reported for CH3CHO in SgrB2(N). This is a factor of 200 larger than the predictions of the new standard gas phase chemistry model of Lee, Bettens, and Herbst (1996), suggesting that the formation of c-C2H4O may be related to molecular formation on interstellar grains. We present observations of the c-C2H4O to CH3CHO abundance ratio in 5 additional molecular clouds. The data were taken in October 1997 with the Swedish-European Submillimeter Telescope in Chile. The confirmation of ethylene oxide in molecular clouds provides an appealing scenario for the first link in the chain of reactions leading to the origin of life, since it has been suggested as a possible pathway to the formation of the related cyclic molecule oxiranecarbonitrile (c-C3H3NO; cf., Dickens et al. 1996), a precursor to the synthesis of sugar phosphates which comprise the backbone of our molecular genetic structure. References: Dickens, J.E., Irvine, W.M., Ohishi, M., Ikeda, M., Ishikawa, S., Nummelin, A., and Hjalmarson, A. 1997, Astrophys. J., 489 (in press). Dickens, J.E. et al. 1996, Orig. Life Evol. Biosphere, 26, 97. Lee, H.-H., Bettens, R.P.A., and Herbst, E. 1996, Astron. Astrophys. Supp., 119, 111.

  20. Two episodes of ethylene oxide poisoning--a case report.

    PubMed

    Lin, T J; Ho, C K; Chen, C Y; Tsai, J L; Tsai, M S

    2001-06-01

    Ethylene oxide is used as a sterilizer, a solvent, a plasticizer and in the manufacture of special solvents, antifreeze, polyester resins and non-ionic surfactants. Its toxicity is caused by an alkylating reaction with most organic substances in the body. Four workers, without any protection, managed the leakage of ethylene oxide from the collecting tank improperly on July 29, 2000. In the same factory, the overflow of ethylene oxide in process resulted in leakage of ethylene oxide again on Aug. 7, 2000. Two workers were poisoned despite wearing full-face respirators with ethylene oxide approved canisters. In these two events, the workers all smelled an ether-like odor. Six workers experienced nausea, vomiting, chest tightness, shortness of breath, dizziness, cough and ocular irritation. One worker had transient loss of consciousness. Oxygen therapy and supportive care were used. Patients were discharged in stable condition. The permissible exposure limit of ethylene oxide in air is 1 ppm as an eight hour TWA. Above 50 ppm, the odor threshold, a positive-pressure supplied air respirator is needed to protect the worker. Full-face respirators with ethylene oxide approved canisters could not protect our cases who smelled the odor and were exposed to an unknown concentration. It is important to wear positive-pressure self-contained breathing apparatuses equipped with full facepieces to clean up the contamination area and rescue the patients. PMID:11593964

  1. New sterilization technologies alternative to ethylene oxide

    NASA Astrophysics Data System (ADS)

    Tabrizian, Maryam; Lerouge, Sophie; Debrie, Anne; Yahia, L'Hocine

    1997-06-01

    Sterilization of biomedical devices may induce bulk and surface modification, responsible for the decrease or loss of their biofunctionality. Pure ethylene oxide (EO) at low temperature and new alternative techniques such as cold gas plasma sterilization have been developed for heat-sensitive polymers. There is a lack of the knowledge concerning their safety in terms of materials damage and consequences on the biofunctionality of sterilized devices. The objective of our work consists in studying bulk and surface changes in biomedical devices induced by these two sterilization techniques. Samples from PVC, Polyurethane, Polyacrylate and Polyethylene-based medical devices are subjected to 1, 5, and 10 sterilization cycles by Steri-Vac-3M (pure EO), Sterrad-100$TM, J&J (gas plasma + H2O2), and studied by X-rays photoelectron spectroscopy. Preliminary results show an increasing in Oxygen/Carbon ratio by a factor of 1.3 to 4.4 between the first and tenth cycle indicating the surface oxidation by gas plasma sterilization processes. Some changes in C-C chemical bounding are associated with EO sterilization.

  2. Health Assessment Document for Ethylene Oxide (External Review Draft)

    EPA Science Inventory

    The largest single use of ethylene oxide is an intermediate in the synthesis of ethylene glycol. However, small amounts of this epoxide are used as a sterilant or pesticide in commodities, pharmaceuticals, medical devices, tobacco, and other items, representing a considerable pot...

  3. 46 CFR 151.50-12 - Ethylene oxide.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-12 Ethylene oxide. (a)(1) Ethylene... liquid or vapor phase, including the vent risers, shall be insulated. Flanges need not be covered, but if... installed to maintain the temperature of the liquid below 90 °F, at least two complete cooling...

  4. 46 CFR 151.50-12 - Ethylene oxide.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-12 Ethylene oxide. (a)(1) Ethylene... liquid or vapor phase, including the vent risers, shall be insulated. Flanges need not be covered, but if... installed to maintain the temperature of the liquid below 90 °F, at least two complete cooling...

  5. 46 CFR 151.50-12 - Ethylene oxide.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-12 Ethylene oxide. (a)(1) Ethylene... liquid or vapor phase, including the vent risers, shall be insulated. Flanges need not be covered, but if... installed to maintain the temperature of the liquid below 90 °F, at least two complete cooling...

  6. Evaluation of the Carcinogenicity of Ethylene Oxide (External Review Draft)

    EPA Science Inventory

    EPA conducted a peer review and public comment of the scientific basis supporting the human health hazard and dose-response assessment of ethylene oxide (cancer) that when finalized will appear on the Integrated Risk Information System (IRIS) database.

  7. Tracing Poly(ethylene-oxide) Crystallization using Atomic Force Microscopy

    NASA Astrophysics Data System (ADS)

    Capaldi, Xavier; Amanuel, Samuel

    The early stages of nucleation and crystallization of Poly(ethylene-oxide) have been studied using Atomic Force Microscopy equipped with a heating and cooling stage. Effects of molecular weight and sample preparation techniques were studied using amplitude and frequency modulation. Mapping the viscoelastic behavior at different temperatures and has enabled the development of a relatively new technique for following the evolution of crystallization and melting of a semi-crystalline polymer. Tracing Poly(ethylene-oxide) Crystallization using Atomic Force Microscopy.

  8. Ammonia and ethylene oxide permeation through selected protective clothing.

    PubMed

    Berardinelli, S P; Moyer, E S; Hall, R C

    1990-11-01

    An automated permeation test system was developed to collect permeation data. Three test specimens were evaluated simultaneously versus a challenge gas. The study evaluated chemical protective clothing garment materials for use by emergency response personnel confronted by ammonia or ethylene oxide in the gas phase. A total of 13 encapsulating suit materials and 2 glove materials were tested. Surgical latex material is not recommended for use in handling ammonia or ethylene oxide; other materials offer much greater protection. PMID:2085165

  9. Evaluating OSHA's ethylene oxide standard: exposure determinants in Massachusetts hospitals.

    PubMed Central

    LaMontagne, A D; Kelsey, K T

    2001-01-01

    OBJECTIVES: This study sought to identify determinants of workplace exposures to ethylene oxide to assess the effect of the Occupational Safety and Health Administration's (OSHA's) 1984 ethylene oxide standard. METHODS: An in-depth survey of all hospitals in Massachusetts that used ethylene oxide from 1990 through 1992 (96% participation, N = 90) was conducted. Three types of exposure events were modeled with logistic regression: exceeding the 8-hour action level, exceeding the 15-minute excursion limit, and worker exposures during unmeasured accidental releases. Covariates were drawn from data representing an ecologic framework including direct and indirect potential exposure determinants. RESULTS: After adjustment for frequencies of ethylene oxide use and exposure monitoring, a significant inverse relation was observed between exceeding the action level and the use of combined sterilizer-aerators, an engineering control technology developed after the passage of the OSHA standard. Conversely, the use of positive-pressure sterilizers that employ ethylene oxide gas mixtures was strongly related to both exceeding the excursion limit and the occurrence of accidental releases. CONCLUSIONS: These findings provide evidence of a positive effect of OSHA's ethylene oxide standard and specific targets for future prevention and control efforts. PMID:11236406

  10. [Production of soy bean inoculants. Behavior of supports based on peat from Tierra del Fuego sterilized by vapor and ethylene oxide].

    PubMed

    Balatti, A P; Mazza, L A

    1979-01-01

    The survival of Rhizobium japonicum was studied in neutralized and sterilized peats from Ushuaia and Rio Grande. The carriers were sterilized by ethylene oxide and by autoclaving. Similar counts for Rhizobium (5 x 10(8) cel/g) were obtained in peat-cultures sterilized by both methods, after eight months. A good nodulation and nitrogen fixation capacity was observed with inoculated soybean plants. Using the strain Rhizobium japonicum E-45, no appreciable difference in symbiotic effectiveness was found between the inoculants prepared with the two peats. PMID:263653

  11. Oxidative degradation and kinetics of chlorinated ethylenes by potassium permanganate

    NASA Astrophysics Data System (ADS)

    Yan, Y. Eugene; Schwartz, Frank W.

    1999-04-01

    The oxidative treatment of chlorinated ethylenes in ground water using permanganate was investigated in a series of batch kinetic tests. Five chlorinated ethylenes including tetrachloroethylene (PCE), trichloroethylene (TCE), and three isomers of dichloroethylenes (DCEs) were examined. The degradation process was rapid with pseudo-first-order rate constants ranging from 4.5×10 -5 to 0.03 s -1 at MnO 4-=1 mM. The rate increased with a decreasing number of chlorine substituents on the ethylene. The higher reactivity of trans-DCE ( kobs=30×10 -3 s -1 at MnO 4-=1 mM) as compared to cis-DCE ( kobs=0.9×10 -3 s -1 at MnO 4-=1 mM) is thought to be caused by a significant steric effect due to the formation of a large cyclic activated complex. TCE oxidation as a second-order reaction was confirmed and the rate constant, k=0.67±0.03 M -1 s -1, is independent of pH over the range of 4-8. The activity of both Cl - and hydrogen ions was monitored over time and suggests essentially complete dechlorination, making the degradation products less harmful than the parent compounds. Competition for MnO 4- from other organic compounds in ground water or highly contaminated ground water was also evaluated in experiments. A simple and quick approach was demonstrated to estimate permanganate consumption by other organic compounds for field applications and to predict the TCE degradation rate in a system involving multiple contaminants. The modeling results suggest that the effect of autocatalysis by MnO 2 on TCE degradation is significant when the system contains high concentration levels of MnO 4- and TOC.

  12. Ethylene Production and Ethylene Effects on Respiration Rate of Postharvest Sugarbeet Roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ethylene elevates respiration, is induced by wounding, and contributes to wound-induced respiration in most postharvest plant products. Ethylene production and its effects on respiration rate, however, have not been determined in sugarbeet (Beta vulgaris L.) root, even though any elevation in respi...

  13. Ethylene dynamics in the CELSS biomass production chamber

    NASA Technical Reports Server (NTRS)

    Rakow, Allen L.

    1994-01-01

    A material balance model for ethylene was developed and applied retrospectively to data obtained in the Biomass Production Chamber of CELSS in order to calculate true plant production rates of ethylene. Four crops were analyzed: wheat, lettuce, soybean, and potato. The model represents an effort to account for each and every source and sink for ethylene in the system. The major source of ethylene is the plant biomass and the major sink is leakage to the surroundings. The result, expressed in the units of ppd/day, were converted to nl of ethylene per gram of plant dry mass per hour and compare favorably with recent glasshouse to belljar experiments.

  14. An analysis of alternative technologies for the removal of ethylene from the CELSS biomass production chamber

    NASA Technical Reports Server (NTRS)

    Rakow, Allen L.

    1995-01-01

    A variety of technologies were analyzed for their potential to remove ethylene from the CELSS Biomass Production Chamber (BPC). During crop production (e.g., lettuce, wheat, soybean, potato) in the BPC ethylene can accumulate in the airspace and subsequently affect plant viability. The chief source of ethylene is the plants themselves which reside in plastic trays containing nutrient solution. The main sink for ethylene is chamber leakage. The removal technology can be employed when deleterious levels (e.g., 50 ppb for potato) of ethylene are exceeded in the BPC and perhaps to optimize the plant growth process once a better understanding is developed of the relationship between exogenous ethylene concentration and plant growth. The technologies examined were catalytic oxidation, molecular sieve, cryotrapping, permanganate absorption, and UV degradation. Upon analysis, permanganate was chosen as the most suitable method. Experimental data for ethylene removal by permanganate during potato production was analyzed in order to design a system for installation in the BPC air duct. In addition, an analysis of the impact on ethylene concentration in the BPC of integrating the Breadboard Scale Aerobic Bioreactor (BSAB) with the BPC was performed. The result indicates that this unit has no significant effect on the ethylene material balance as a source or sink.

  15. Decomposition of ethylene oxide in the RF plasma environment.

    PubMed

    Liao, W T; Lee, W J; Chen, C Y; Shih, M

    2001-02-01

    A radio frequency (RF) plasma system was used to decompose the ethylene oxide (EO) contained gas in the EO/Ar, and EO/O2/Ar system, respectively. The reactants and final products were analyzed by using FTIR (Fourier transform infrared spectroscopy). The effects of plasma operational parameters, including input power wattage (W), total gas flow rate (Q), feeding concentration (C) of EO and operational pressure for EO decomposition were evaluated. Due to the importance of the high-energy electrons in the RF plasma system, the EO decomposition fraction in plasma reaction increased with decreasing operational pressure, while that of thermal reaction, reported by previous investigations, increased with increasing operational pressure. However, owing to the electrophilic characteristic of oxygen atoms in the EO molecule causing the effect of electron attachment, in conditions of higher EO feeding concentration, the pressure dependence became the same for both plasma- and thermal-reaction. The EO oxidation reaction has also been investigated, the result shows that EO almost completely oxidized at 600-692 K gas temperature. The main products for the EO/Ar system are CO, CH4, C2H6, C2H4, and C2H2, and those for the EO/O2/Ar system are CO2 and H2O. PMID:11349375

  16. The oxidation of copper catalysts during ethylene epoxidation.

    PubMed

    Greiner, M T; Jones, T E; Johnson, B E; Rocha, T C R; Wang, Z J; Armbrüster, M; Willinger, M; Knop-Gericke, A; Schlögl, R

    2015-10-14

    The oxidation of copper catalysts during ethylene epoxidation was characterized using in situ photoemission spectroscopy and electron microscopy. Gas chromatography, proton-transfer reaction mass spectrometry and electron-ionization mass spectrometry were used to characterize the catalytic properties of the oxidized copper. We find that copper corrodes during epoxidation in a 1 : 1 mixture of oxygen and ethylene. The catalyst corrosion passes through several stages, beginning with the formation of an O-terminated surface, followed by the formation of Cu2O scale and eventually a CuO scale. The oxidized catalyst exhibits measurable activity for ethylene epoxidation, but with a low selectivity of <3%. Tests on pure Cu2O and CuO powders confirm that the oxides intrinsically exhibit partial-oxidation activity. Cu2O was found to form acetaldehyde and ethylene epoxide in roughly equal amounts (1.0% and 1.2% respectively), while CuO was found to form much less ethyl aldehyde than ethylene epoxide (0.1% and 1.0%, respectively). Metallic copper catalysts were examined in extreme dilute-O2 epoxidation conditions to try and keep the catalyst from oxidizing during the reaction. It was found that in feed of 1 part O2 to 2500 parts C2H4 (PO2 = 1.2 × 10(-4) mbar) the copper surface becomes O-terminated. The O-terminated surface was found to exhibit partial-oxidation selectivity similar to that of Cu2O. With increasing O2 concentration (>8/2500) Cu2O forms and eventually covers the surface. PMID:26345450

  17. 40 CFR 180.151 - Ethylene oxide; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., except basil 7 Licorice, roots 7 Peppermint, tops, dried 7 Sesame, seed 7 Spearmint, tops, dried 7 Vegetable, dried 7 Walnut 50 (2) Tolerances are established for residues of the ethylene oxide reaction... 19, dried, except basil 940 Licorice, roots 940 Peppermint, tops, dried 940 Sesame, seed...

  18. 40 CFR 180.151 - Ethylene oxide; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., except basil 7 Licorice, roots 7 Peppermint, tops, dried 7 Sesame, seed 7 Spearmint, tops, dried 7 Vegetable, dried 7 Walnut 50 (2) Tolerances are established for residues of the ethylene oxide reaction... 19, dried, except basil 940 Licorice, roots 940 Peppermint, tops, dried 940 Sesame, seed...

  19. 40 CFR 180.151 - Ethylene oxide; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., except basil 7 Licorice, roots 7 Peppermint, tops, dried 7 Sesame, seed 7 Spearmint, tops, dried 7 Vegetable, dried 7 Walnut 50 (2) Tolerances are established for residues of the ethylene oxide reaction... 19, dried, except basil 940 Licorice, roots 940 Peppermint, tops, dried 940 Sesame, seed...

  20. 40 CFR 180.151 - Ethylene oxide; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., except basil 7 Licorice, roots 7 Peppermint, tops, dried 7 Sesame, seed 7 Spearmint, tops, dried 7 Vegetable, dried 7 Walnut 50 (2) Tolerances are established for residues of the ethylene oxide reaction... 19, dried, except basil 940 Licorice, roots 940 Peppermint, tops, dried 940 Sesame, seed...

  1. 40 CFR 180.151 - Ethylene oxide; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., except basil 7 Licorice, roots 7 Peppermint, tops, dried 7 Sesame, seed 7 Spearmint, tops, dried 7 Vegetable, dried 7 Walnut 50 (2) Tolerances are established for residues of the ethylene oxide reaction... 19, dried, except basil 940 Licorice, roots 940 Peppermint, tops, dried 940 Sesame, seed...

  2. 21 CFR 172.770 - Ethylene oxide polymer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ethylene oxide polymer. 172.770 Section 172.770 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR...

  3. 21 CFR 172.770 - Ethylene oxide polymer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ethylene oxide polymer. 172.770 Section 172.770 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Other Specific Usage Additives §...

  4. 21 CFR 172.770 - Ethylene oxide polymer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ethylene oxide polymer. 172.770 Section 172.770 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR...

  5. ETHYLENE OXIDE CONTROL TECHNOLOGY DEVELOPMENT FOR HOSPITAL STERILIZERS

    EPA Science Inventory

    The report discusses the development of ethylene oxide (EO) control technology for hospital sterilizers. Hospitals sterilize heat-sensitive items in gas sterilizers that use a mixture of EO (12 wt %) and a chlorofluorocarbon (CFC) (88 wt %). The active sterilizing agent is EO. Th...

  6. NITRIC OXIDE AND NITRITE TREATMENTS REDUCE ETHYLENE EVOLUTION FROM APPLE FRUIT DISKS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Golden Delicious’ apple [Malus sylvestris var. domestica (Borkh.)] cortex disks suspended in solutions containing a nitric oxide ('NO) donor [S-nitrosoglutathione (GSNO) or sodium nitroprusside (SNP)], 'NO gas, or nitrite (KNO2) were utilized to identify impacts of 'NO on ethylene production and NO...

  7. Ethylene production throughout growth and development of plants

    NASA Technical Reports Server (NTRS)

    Wheeler, Raymond M.; Peterson, Barbara V.; Stutte, Gary W.

    2004-01-01

    Ethylene production by 10 or 20 m2 stands of wheat, soybean, lettuce, potato, and tomato was monitored throughout growth and development in an atmospherically closed plant chamber. Chamber ethylene levels varied among species and rose during periods of canopy expansion and rapid growth for all species. Following this, ethylene levels either declined during seed fill and maturation for wheat and soybean, or remained relatively constant for potato and tomato (during flowering and early fruit development). Lettuce plants were harvested during rapid growth and peak ethylene production. Chamber ethylene levels increased rapidly during tomato ripening, reaching concentrations about 10 times that measured during vegetative growth. The highest ethylene production rates during vegetative growth ranged from 1.6 to 2.5 nmol m-2 d-1 during rapid growth of lettuce and wheat stands, or about 0.3 to 0.5 nmol g-1 fresh weight per hour. Estimates of stand ethylene production during tomato ripening showed that rates reached 43 nmol m-2 d-1 in one study and 93 nmol m-2 d-1 in a second study with higher lighting, or about 50x that of the rate during vegetative growth of tomato. In a related test with potato, the photoperiod was extended from 12 to 24 hours (continuous light) at 58 days after planting (to increase tuber yield), but this change in the environment caused a sharp increase in ethylene production from the basal rate of 0.4 to 6.2 nmol m-2 d-1. Following this, the photoperiod was changed back to 12 h at 61 days and ethylene levels decreased. The results suggest three separate categories of ethylene production were observed with whole stands of plants: 1) production during rapid vegetative growth, 2) production during climacteric fruit ripening, and 3) production from environmental stress.

  8. Surface activity of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) copolymers

    SciTech Connect

    Alexandridis, P.; Athanassiou, V.; Fukuda, Shinya; Hatton, T.A. )

    1994-08-01

    The surface tension of aqueous solutions of seven poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO-PPO-PEO) Pluronic copolymers, covering a wide range of molecular weights (3400-14600) and PPO/PEO ratios (0.19-1.79), was determined over the 10[sup [minus]5]-10% w/v concentration range, at two temperatures (25 and 35[degree]C). Two breaks (changes in slope) were observed in the surface tension vs log concentration curve for most of the copolymers. The low-concentration break, occurring at bulk copolymer concentrations of approximately 10[sup [minus]3]%, is believed to originate from rearrangement of the copolymer molecules on the surface at complete coverage of the air/water interface. The breaks at the high-concentration part of the surface tension curve occurred at concentrations that correspond to the critical micellization concentration values as determined by a dye solubilization technique. The surface area per copolymer molecule, A, increased as a function of the number of EO segments, N[sub EO], obeying a scaling law (A [approx] N[sub EO][sup 1/2]) similar to that of lower molecular weight C[sub i]E[sub j] nonionic surfactants. 56 refs., 6 figs., 2 tabs.

  9. Ethylene oxidation chemistry in a well-stirred reactor

    SciTech Connect

    Marinov, N.; Malte, P.

    1994-09-01

    Ethylene is an important intermediate in the combustion of methane, larger aliphatic hydrocarbons, and aromatics. Detailed fuel-lean C{sub 2}H{sub 4}H{sub 2}O/air well-stirred reactor data by Thornton were used to analyze reported combustion chemistry mechanisms and the development of this study`s ethylene oxidation mechanism. The data set had been obtained for the temperature range 1,003 to 1,253 K and ethylene-oxygen equivalence ratio range 0.086 to 0.103, at atmospheric pressure. Mechanisms were derived from reaction sets of Westbrook and Pitz, and Dagaut, Cathonnet and Boettner. Examination of each reported mechanism indicated unusually large kinetic rates for the vinyl decomposition reaction were used in order to obtain agreement with the Thornton data set. An ethylene oxidation model was developed in order to address the mechanistic problems of the previous models. This study`s mechanism well simulated the overall rate of ethylene oxidation and concentration profiles of CO, CO{sub 2}, H{sub 2}, CH{sub 2}O, C{sub 2}H{sub 2}, CH{sub 3}OH, CH{sub 4}, and C{sub 2}H{sub 6}. Successful predictions by the model were dependent on a new high temperature vinyl oxidation reaction route, C{sub 2}H{sub 3} + O{sub 2} = CH{sub 2}CHO + O with a branching ratio of 1.19--1.21 at 1,053 K to 1.63--2.47 at 1,253 K. The branching ratio values were dependent upon the extent of fall-off for the C{sub 2}H{sub 3} + O{sub 2} = CH{sub 2}O + HCO reaction. 132 refs.

  10. Synthesis of ethylene and ethane by partial oxidation of methane over lithium-doped magnesium oxide

    NASA Astrophysics Data System (ADS)

    Ito, Tomoyasu; Lunsford, Jack H.

    1985-04-01

    The partial oxidation of methane into more useful chemicals such as methanol, ethylene and benzene has been investigated extensively, although yields for these products have been poor1-4. Moreover, in several of these processes the required oxidant is N2O rather than O2. Recent work5 in our laboratory has demonstrated that lithium-doped magnesium oxide (Li/MgO) in the presence of O2 has high activity for abstracting H from CH4 to form .CH3 radicals. This suggests that C2H6 and C2H4 (C2 compounds) are produced by a coupling between two gaseous .CH3 radicals formed on this catalyst. We report here our success in converting CH4 to C2 compounds in high yields in conventional catalytic conditions.

  11. Ethylene production by plants in a closed environment

    NASA Astrophysics Data System (ADS)

    Wheeler, R. M.; Peterson, B. V.; Sager, J. C.; Knott, W. M.

    Ethylene production by 20-m^2 stands of wheat, soybean, lettuce and potato was monitored throughout growth and development in NASA's Controlled Ecological Life Support System (CELSS) Biomass Production Chamber. Chamber ethylene concentrations rose during periods of rapid growth for all four species, reaching 120 parts per billion (ppb) for wheat, 60 ppb for soybean, and 40 to 50 ppb for lettuce and potato. Following this, ethylene concentrations declined during seed fill and maturation (wheat and soybean), or remained relatively constant (potato). Lettuce plants were harvested during rapid growth and peak ethylene production. The highest ethylene production rates (unadjusted for chamber leakage) ranged from 0.04 to 0.06 ml m^-2 day^-1 during rapid growth of lettuce and wheat stands, or approximately 0.8 to 1.1 nl g^-1 fresh weight h^-1 Results suggest that ethylene production by plants is a normal event coupled to periods of rapid metabolic activity, and that ethylene removal or control measures should be considered for growing crops in a tightly closed CELSS.

  12. Ethylene Production by Plants in a Closed Environment

    NASA Technical Reports Server (NTRS)

    Wheeler, R. M.; Peterson, B. V.; Sager, J. C.; Knott, W. M.

    1996-01-01

    Ethylene production by 20-sq m stands of wheat, soybean, lettuce and potato was monitored throughout growth and development in NASA's Controlled Ecological Life Support System (CELSS) Biomass Production Chamber. Chamber ethylene concentrations rose during periods of rapid growth for all four species, reaching 120 parts per billion (ppb) for wheat, 60 ppb for soybean, and 40 to 50 ppb for lettuce and potato. Following this, ethylene concentrations declined during seed fill and maturation (wheat and soybean), or remained relatively constant (potato). Lettuce plants were harvested during rapid growth and peak ethylene production. The highest ethylene production rates (unadjusted for chamber leakage) ranged from 0.04 to 0.06 ml/sq m/day during rapid growth of lettuce and wheat stands, or approximately 0.8 to 1.1 ml/g fresh weight/h. Results suggest that ethylene production by plants is a normal event coupled to periods of rapid metabolic activity, and that ethylene removal or control measures should be considered for growing crops in a tightly closed CELSS.

  13. Alternative control technology document: Ethylene oxide sterilization/fumigation operations

    SciTech Connect

    Not Available

    1989-03-01

    This report presents technical information that State and local agencies can use to develop strategies for reducing VOC (i.e., EO) emissions for sterilization/fumigation facilities. The information in the document will allow planners to identify available control alternatives and evaluate the VOC reduction and cost of implementing controls. The document provides information on sterilization/fumigation processes, EO (ethylene oxide) emissions, and emission reductions, and cost associated with the application of control units. Section 2.0 presents a summary of the findings of the study. Section 3.0 provides a description of sterilization/fumigation facility operations and emission sources. Section 4.0 provides a description of alternative control techniques for the reduction of ethylene oxide emissions. Section 5.0 presents a cost analysis that includes a methodology for computing annualized equipment and operating costs. A list of contacts at various Federal agencies who are knowledgeable about sterilization/fumigation processes is presented in Appendix A.

  14. Effect of nitric oxide on ethylene synthesis and softening of banana fruit slice during ripening.

    PubMed

    Cheng, Guiping; Yang, En; Lu, Wangjin; Jia, Yongxia; Jiang, Yueming; Duan, Xuewu

    2009-07-01

    The effects of nitric oxide (NO) on ethylene synthesis and softening of ripening-initiated banana slice were investigated. Fruit firmness, color, and contents of starch and acid-soluble pectin (ASP) were measured. In addition, ethylene production, 1-aminocyclopropane-1-carboxylic acid (ACC) content, expression and activities of ACC synthase (ACS) and ACC oxidase (ACO), and activities of cell-wall-modifying enzymes, polygalacturonase (PG), pectin methylesterase (PME), and endo-beta-1,4-glucanase, were analyzed. Application of NO reduced ethylene production, inhibited degreening of the peel and delayed softening of the pulp. The decrease of ethylene production was associated with the reduction in the activity of ACO and the expression of the MA-ACO1 gene. Moreover, the NO-treated fruit showed a lower expression of the MA-ACS1 gene but higher ACS activity and ACC content. In addition, NO treatment decreased the activities of PG, PME, and endo-beta-1,4-glucanase and maintained higher contents of ASP and starch, which may account for the delay of softening. We proposed that the inhibition of ACO activity and transcription of gene MA-ACO1 by NO resulted in decreased ethylene synthesis and the delay of ripening of banana slice. PMID:19534461

  15. Chemical modifications of therapeutic proteins induced by residual ethylene oxide.

    PubMed

    Chen, Louise; Sloey, Christopher; Zhang, Zhongqi; Bondarenko, Pavel V; Kim, Hyojin; Ren, Da; Kanapuram, Sekhar

    2015-02-01

    Ethylene oxide (EtO) is widely used in sterilization of drug product primary containers and medical devices. The impact of residual EtO on protein therapeutics is of significant interest in the biopharmaceutical industry. The potential for EtO to modify individual amino acids in proteins has been previously reported. However, specific identification of EtO adducts in proteins and the effect of residual EtO on the stability of therapeutic proteins has not been reported to date. This paper describes studies of residual EtO with two therapeutic proteins, a PEGylated form of the recombinant human granulocyte colony-stimulating factor (Peg-GCSF) and recombinant human erythropoietin (EPO) formulated with human serum albumin (HSA). Peg-GCSF was filled in an EtO sterilized delivery device and incubated at accelerated stress conditions. Glu-C peptide mapping and LC-MS analyses revealed residual EtO reacted with Peg-GCSF and resulted in EtO modifications at two methionine residues (Met-127 and Met-138). In addition, tryptic peptide mapping and LC-MS analyses revealed residual EtO in plastic vials reacted with HSA in EPO formulation at Met-328 and Cys-34. This paper details the work conducted to understand the effects of residual EtO on the chemical stability of protein therapeutics. PMID:25407640

  16. Ethylene oxidation in a well-stirred reactor

    SciTech Connect

    Marinov, N.M.; Malte, P.C.

    1994-10-01

    The detailed ethylene oxidation data set of Thornton, obtained for a well-stirred reactor operated fuel-lean at atmospheric pressure and for temperatures of 1003K to 1253K, is used as a basis for the comparison of chemical kinetic mechanisms reported in the literature and for the development of a new ethylene oxidation mechanism. The mechanisms examined are those of Westbrook and Pitz and Dagaut et al. These mechanisms indicated that unusually large rates for the vinyl decomposition reaction are required to obtain agreement with the Thornton data set. A new ethylene oxidation mechanism is developed in order to overcome some of the drawbacks of the previous mechanisms. The new mechanism closely simulates the overall rate of loss of ethylene, and the concentation of CO, CO{sub 2}, H{sub 2}, CH{sub 2}O, C{sub 2}H{sub 2}, CH{sub 3}OH, CH{sub 4}, and C{sub 2}H{sub 6} measured for the stirred reactor. Predictions by this mechanism are dependent on a new high temperature vinyl oxidation route, C{sub 2}H{sub 3} + O{sub 2} = CH{sub 2}CHO + O with a k{sub C2H3+O2=CH2CHO+O}/k{sub C2H3+O2=CH2O+HCO} branching ratio of 1.20 at 1053K to 2.05 at 1253K. The branching ratio values were dependent upon the extent of fall-off for the C{sub 2}H{sub 3} + O{sub 2} = CH{sub 2}O + HCO reaction.

  17. Enhanced ethylene production via flash methanolysis of coal

    SciTech Connect

    Sundaram, M.S.; Steinberg, M.; Fallon, P.

    1984-01-01

    In an on-going pyrolysis research project at the Brookhaven National Laboratory, the methods to increase the yield of ethylene through flash methanolysis of coal is being investigated. Flash methanolysis is defined as pyrolysis of coal under pressure in an atmosphere of methane. This study attempts to identify the influence of important process variables such as reaction temperature, gas pressure, solids residence time, gas/solids ratio etc. on the production characteristics of ethylene and other pyrolysis products.

  18. Enhanced ethylene production via flash methanolysis of coal

    SciTech Connect

    Sundaram, M.S.; Fallon, P.; Steinberg, M.

    1984-04-01

    In an on-going pyrolysis research project at the Brookhaven National Laboratory, the methods to increase the yield of ethylene through flash methanolysis of coal is being investigated. Flash methanolysis is defined as pyrolysis of coal under pressure in an atmosphere of methane. This study attempts to identify the influence of important process variables such as reaction temperature, gas pressure, solids residence time, gas/solids ratio etc. on the production characteristics of ethylene and other pyrolysis products.

  19. Intermolecular potential energy surface and thermophysical properties of ethylene oxide

    SciTech Connect

    Crusius, Johann-Philipp Hassel, Egon; Hellmann, Robert; Bich, Eckard

    2014-10-28

    A six-dimensional potential energy hypersurface (PES) for two interacting rigid ethylene oxide (C{sub 2}H{sub 4}O) molecules was determined from high-level quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the MP2 and CCSD(T) levels of theory was utilized to determine interaction energies for 10178 configurations of two molecules. An analytical site-site potential function with 19 sites per ethylene oxide molecule was fitted to the interaction energies and fine tuned to agree with data for the second acoustic virial coefficient from accurate speed of sound measurements. The PES was validated by computing the second virial coefficient, shear viscosity, and thermal conductivity. The values of these properties are substantiated by the best experimental data as they tend to fall within the uncertainty intervals and also obey the experimental temperature functions, except for viscosity, where experimental data are insufficient. Due to the lack of reliable data, especially for the transport properties, our calculated values are currently the most accurate estimates for these properties of ethylene oxide.

  20. Intermolecular potential energy surface and thermophysical properties of ethylene oxide.

    PubMed

    Crusius, Johann-Philipp; Hellmann, Robert; Hassel, Egon; Bich, Eckard

    2014-10-28

    A six-dimensional potential energy hypersurface (PES) for two interacting rigid ethylene oxide (C2H4O) molecules was determined from high-level quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the MP2 and CCSD(T) levels of theory was utilized to determine interaction energies for 10178 configurations of two molecules. An analytical site-site potential function with 19 sites per ethylene oxide molecule was fitted to the interaction energies and fine tuned to agree with data for the second acoustic virial coefficient from accurate speed of sound measurements. The PES was validated by computing the second virial coefficient, shear viscosity, and thermal conductivity. The values of these properties are substantiated by the best experimental data as they tend to fall within the uncertainty intervals and also obey the experimental temperature functions, except for viscosity, where experimental data are insufficient. Due to the lack of reliable data, especially for the transport properties, our calculated values are currently the most accurate estimates for these properties of ethylene oxide. PMID:25362314

  1. Enhanced ethylene production via flash methanolysis of coal

    SciTech Connect

    Sundaram, M.S.; Steinberg, M.; Fallon, P.

    1983-12-01

    According to a recent report, an estimated 31 billion pounds of ethylene was produced in the US alone. Ethylene is an important raw material in the vast plastic and polymer markets. An upward trend in the demand for ethylene has been predicted for the future years. Currently, ethylene is produced mainly through thermal and catalytic hydrocracking of ethane and other hydrocarbons. Although a large amount of work has been performed on the production of gaseous and liquid fuels from coal, much less attention has been focused on the production of ehtylene using coal as the raw material. In an on-going pyrolysis research project at the Brookhaven National Laboratory, methods for increasing the yield of ethylene through flash methanolysis of coal are being investigated. Flash methanolysis is defined as pyrolysis of coal under pressure in an atmosphere of methane. This study attempts to identify the influence of important process variables such as reaction temperature, gas pressure, solids residence time, gas/solids ratio etc on the production of ethylene and other pyrolysis products. We have shown that there are definite advantages in the use of methane as an atmosphere in the flash pyrolysis of coal. At temperatures higher than 800/sup 0/C, 2 to 5 times greater yields of ethylene are obtainable in methane atmosphere compared to flash pyrolysis in an inert helium atmosphere. An enhancement in the yield of ethylene and BTX are important raw materials in the vast polymer and plastic markets, flash methanolysis of coal has potential process applications. 5 references, 4 figures, 6 tables.

  2. Carbohydrates Stimulate Ethylene Production in Tobacco Leaf Discs 1

    PubMed Central

    Meir, Shimon; Philosoph-Hadas, Sonia; Epstein, Ephraim; Aharoni, Nehemia

    1985-01-01

    Various naturally occurring carbohydrates, applied at a concentration range of 1 to 100 mm, stimulated ethylene production for several days in indoleacetic acid (IAA)-treated or untreated tobacco (Nicotiana tabacum L. cv `Xanthi') leaf discs. The lag period for this sugar-stimulated ethylene production was 8 to 12 hours after excision in the untreated leaf discs, but less than 2 hours in the IAA-treated ones. Among the tested carbohydrates, 12 were found to increase synergistically ethylene production, with d-galactose, sucrose, and lactose being the most active; mannitol and l-glucose had no effect. The extent and duration of the increased ethylene production was dependent upon the type of sugar applied, the tissue's age, and the existence of both exogenous IAA and sugar in the medium. Sucrose appeared to elicit a continuous IAA effect for 48 hours, as expressed by increased ethylene production, even when IAA was removed from the medium after a 4-hour pulse. Sucrose stimulated both the uptake and decarboxylation of [1-14C]IAA, as well as the hydrolysis of the esteric and amide IAA conjugates formed in the tissue after application of free IAA. This gradual hydrolysis was accompanied by a further accumulation of a third IAA metabolite. Moreover, synthetic indole-3-acetyl-l-alanine increased ethylene production mainly with sucrose, and this effect was accompanied by its increased decarboxylation and turnover pattern suggesting that release of free IAA was involved. An esteric IAA conjugate, tentatively identified by GC retention time was found to be the major component (84%) of the naturally occurring IAA conjugates in tobacco leaves. Accordingly the sucrose-stimulated ethylene production in tobacco leaves can be ascribed mainly to the sucrose-stimulated hydrolysis of the esteric IAA conjugate. PMID:16664185

  3. Microwave cavity spectrometer for process monitoring of ethylene oxide sterilization

    NASA Astrophysics Data System (ADS)

    Zhu, Z.; Gibson, C.; Samuel, A. H.; Matthews, I. P.

    1993-01-01

    This article reports a novel and simple cavity spectrometer for process monitoring of ethylene oxide sterilization, in which the source frequency, cavity resonant frequency, and gas absorption center frequency are asynchronous with respect to each other, thus, enabling sophisticated signal enhancement techniques to be employed without the need to engage the Stark effect. The operation of the device is such that the source frequency sweeps across a given range (F1 to F2) which contains one of the absorption peaks of the analyte gas (gases) of interest while the cavity resonant frequency Fr is oscillated within the profile of the absorption peak. Signal enhancement is achieved by adding a relatively small magnitude/high-frequency ``dither'' signal to the source frequency sweep pattern. The salient information of the gas absorption due to the oscillation of the resonant frequency of the cavity is carried by the ``dither'' signal and amplified and extracted by a series of tuned amplifiers and demodulators. Although the device is still at the initial design stage, a working prototype has been constructed in order to test the feasibility of the novel asynchronous modulation technique. This was achieved by successfully demonstrating that the device operates in an expected manner to within a standard error of 8.3%. It is believed that this error largely results from mechanical components. The significance of this error is greatly reduced when the spectrometer is operated in a large signal scanning mode as is the case when we apply the ``power saturation'' technique to measure the concentration of ethylene oxide in the resonant cavity. This measurement showed that there is a good linear correlation between the output signal and the concentration of ethylene oxide gas (to within a standard error of 4%).

  4. Health-hazard evaluation report HETA 83-335-1618, Kendall Company, Augusta, Georgia. [Ethylene oxide

    SciTech Connect

    Seligman, P.; Gorman, R.

    1985-08-01

    Environmental and breathing-zone samples were analyzed for ethylene oxide at the Kendall Company, Augusta, Georgia in August, 1983 and July and August, 1984. The evaluation was requested confidentially to investigate employee complaints of eye irritation and neurologic symptoms and concern over an excessive number of miscarriages. Physicians at the Medical College of Georgia had reported cases of peripheral neuropathy and cataracts related to ethylene-oxide exposure. Twenty-one employees were interviewed. Company medical records were reviewed. Ethylene-oxide concentrations ranged from nondetectable to 0.83 part per million (ppm). The OSHA standard for ethylene oxide is 1.00 ppm. Grab samples taken during sterilizer down/loading contained 0.3 to 25.0ppm ethylene oxide. Medical records confirmed three cases of neuropathy and four of cataracts. Headache, eye irritation, and fatigue were the most prominent symptoms reported. Many of these symptoms were resolved when ethylene oxide was removed from the alcohol wipes. Five of six miscarriages were not occupationally related. The authors conclude that cases of peripheral neuropathy and cataracts among ethylene-oxide sterilizer operators can be related to past exposures, which were higher. Recommendations include using engineering controls to reduce ethylene-oxide exposure further and complying with OSHA recommendations in monitoring employees exposed to action-level concentrations of 0.5ppm ethylene oxide.

  5. Preparation of bank bone using defatting, freeze-drying and sterilisation with ethylene oxide gas. Part 1. Experimental evaluation of its efficacy and safety.

    PubMed

    Kakiuchi, M; Ono, K; Nishimura, A; Shiokawa, H

    1996-01-01

    We devised a method of sterilising bone allografts which consists of defatting in chloroform and methanol, freeze-drying and sterilisation with ethylene oxide gas. The purpose of defatting and freeze-drying was to facilitate subsequent sterilisation by eliminating the barrier to diffusion of the gas into bone, to lower residual levels of ethylene oxide and its toxic by-products, to eliminate alloantigens and to make storage possible at room temperature. The efficacy and safety of the method were evaluated by testing the sterilisation of infected bone from 6 patients with active chronic osteomyelitis, the penetration of ethylene oxide into human femoral heads treated by this or by freeze-drying or freeze-thawing, and the desorption of ethylene oxide and its toxic by-products from pieces of bone treated by these methods. All the samples of infected bone tested negative for bacteria after treatment. The gas penetrated into the central area of the femoral heads in a few hours. Residual levels of ethylene oxide and its toxic by-products were much lower in the treated bone than in freeze-dried or freeze-thawed bone, and decreased quickly in flowing air. Prior defatting and freeze-drying facilitated penetration of ethylene oxide into bone during sterilisation and the desorption of ethylene oxide and its toxic by-products after sterilisation. Preparation under clean, but not sterile, conditions and storage at room temperature make bone banking more practical and efficient. PMID:8832315

  6. Simulating the in situ oxidative treatment of chlorinated ethylenes by potassium permanganate

    NASA Astrophysics Data System (ADS)

    Zhang, Hubao; Schwartz, Franklin W.

    2000-10-01

    Several laboratory and field studies have demonstrated the potential viability of oxidation schemes using MnO4- for the in situ treatment of source areas, which are contaminated by chlorinated ethylenes (PCE, TCE, and DCE). Chemically, the chlorinated ethylenes are oxidized to CO2, Cl-, and MnO2. The goal of this study was to develop a theoretical framework for the chemical and physical processes involved. To this end, a computer model was created to simulate the coupled processes of nonaqueous phase liquid (NAPL) dissolution, chemical reactions, and solute mass transport in the in situ chemical oxidization scheme. The model incorporates a kinetic description of reactions between the MnO4- and the chlorinated ethylenes and the rate of dissolution of the NAPL. A Strang operator-splitting method, which coupled the different physical and chemical processes and an exponentially expressed solution of the kinetic equations, led to a significant speed up in the solution process. The products were calculated based on the stoichiometry of the reaction. We demonstrated the capabilities of this code using already published results of column, test cell, and field experiments. Generally, the simulated results matched well with experimental measurements. The computer model provides a useful tool for assisting in the design and the prediction of the oxidization processes under field conditions.

  7. Reduced Water Density in a Poly(ethylene oxide) Brush

    SciTech Connect

    Lee, Hoyoung; Kim, Dae Hwan; Park, Hae-Woong; Mahynski, Nathan A.; Kim, Kyungil; Meron, Mati; Lin, Binhua; Won, You-Yeon

    2012-09-05

    A model poly(ethylene oxide) (PEO) brush system, prepared by spreading a poly(ethylene oxide)-poly(n-butyl acrylate) (PEO-PnBA) amphiphilic diblock copolymer onto an air-water interface, was investigated under various grafting density conditions by using the X-ray reflectivity (XR) technique. The overall electron density profiles of the PEO-PnBA monolayer in the direction normal to the air-water interface were determined from the XR data. From this analysis, it was found that inside of the PEO brush, the water density is significantly lower than that of bulk water, in particular, in the region close to the PnBA-water interface. Separate XR measurements with a PnBA homopolymer monolayer confirm that the reduced water density within the PEO-PnBA monolayer is not due to unfavorable contacts between the PnBA surface and water. The above result, therefore, lends support to the notion that PEO chains provide a hydrophobic environment for the surrounding water molecules when they exist as polymer brush chains.

  8. Relationships between respiration, ethylene, and aroma production in ripening banana.

    PubMed

    Golding, J B; Shearer, D; McGlasson, W B; Wyllie, S G

    1999-04-01

    Mature green bananas were treated with the ethylene antagonist 1-methylcyclopropene (1-MCP) at intervals during the 24 h period after initiation of ripening with propylene. Following 1-MCP treatment, the fruits were ripened in either air or propylene while ethylene, carbon dioxide, and volatile production and composition were monitored at regular intervals. The application of 1-MCP significantly delayed and suppressed the onset and magnitude of fruit respiration and volatile production. The 1-MCP treatments also caused a quantitative change in the composition of the aroma volatiles, resulting in a substantial increase in the concentration of alcohols and a decrease in their related esters. The results showed that ethylene has a continuing role in integrating many of the biochemical processes that take place during the ripening of bananas. PMID:10564032

  9. Solubilisation of drugs in micellar solutions of diblock copolymers of ethylene oxide and styrene oxide.

    PubMed

    Crothers, Michael; Ricardo, Nagíla M P S; Heatley, Frank; Nixon, S Keith; Attwood, David; Booth, Colin

    2008-06-24

    The solubilisation of two poorly soluble drugs, furosemide and nabumetone, in micellar solutions of diblock copolymers of ethylene oxide and styrene oxide has been studied at 25 and 37 degrees C and solubilisation capacities compared with published values for griseofulvin and docetaxel. Solubilisation in the micelle core, corrected for the different proportions of poly(styrene oxide) in the copolymers, was similar for all four drugs. The highest solubilisation capacities were found for a copolymer with worm-like micelles. PMID:18417305

  10. Infrared spectroscopy and photochemistry of iron-ethylene oxide in cryogenic matrices. The FTIR spectrum of vinyl iron hydroxide

    SciTech Connect

    Kafafi, Z.H.; Hauge, R.H.; Billups, W.E.; Margrave, J.L.

    1987-08-05

    The mechanism of the cryogenic reaction between an iron atom and an ethylene oxide molecule has been delineated. Iron spontaneously inserted into the carbon-oxygen bond of the cyclic molecule and formed the first unligated metallaoxetane. Upon visible photolysis of ferraoxetane, a metathesis reaction was observed where cleavage occurred through the iron-carbon and the carbon-oxygen bonds of the metallacycle. UV photolysis of the reaction intermediate, an iron oxide ..pi..-complexed to ethylene, led to the activation of one of the C-H bonds of ethylene and the formation of the final product, vinyl iron hydroxide. Similar reaction pathways were observed for the diiron molecule reaction with ethylene oxide. Evidence for the double insertion of two iron atoms into the C-O bonds of ethylene oxide and the subsequent formation of a five-membered oxametallacycle ring has been seen through the detection of frequencies characteristic of an Fe-O-Fe stretching mode and a carbon-carbon stretching mode in the case of the perdeuterio product.

  11. 21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... carboxymethylcellulose sodium denture adhesive. 872.3410 Section 872.3410 Food and Drugs FOOD AND DRUG ADMINISTRATION....3410 Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive is a...

  12. 21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... carboxymethylcellulose sodium denture adhesive. 872.3410 Section 872.3410 Food and Drugs FOOD AND DRUG ADMINISTRATION....3410 Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive is a...

  13. 21 CFR 872.3450 - Ethylene oxide homopolymer and/or karaya denture adhesive.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... adhesive. 872.3450 Section 872.3450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... homopolymer and/or karaya denture adhesive. (a) Identification. Ethylene oxide homopolymer and/or karaya denture adhesive is a device composed of ethylene oxide homopolymer and/or karaya intended to be...

  14. 21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... carboxymethylcellulose sodium denture adhesive. 872.3410 Section 872.3410 Food and Drugs FOOD AND DRUG ADMINISTRATION....3410 Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive is a...

  15. 21 CFR 872.3450 - Ethylene oxide homopolymer and/or karaya denture adhesive.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... adhesive. 872.3450 Section 872.3450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... homopolymer and/or karaya denture adhesive. (a) Identification. Ethylene oxide homopolymer and/or karaya denture adhesive is a device composed of ethylene oxide homopolymer and/or karaya intended to be...

  16. 21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... carboxymethylcellulose sodium denture adhesive. 872.3410 Section 872.3410 Food and Drugs FOOD AND DRUG ADMINISTRATION....3410 Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive is a...

  17. 21 CFR 872.3450 - Ethylene oxide homopolymer and/or karaya denture adhesive.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... adhesive. 872.3450 Section 872.3450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... homopolymer and/or karaya denture adhesive. (a) Identification. Ethylene oxide homopolymer and/or karaya denture adhesive is a device composed of ethylene oxide homopolymer and/or karaya intended to be...

  18. 21 CFR 872.3450 - Ethylene oxide homopolymer and/or karaya denture adhesive.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... adhesive. 872.3450 Section 872.3450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... homopolymer and/or karaya denture adhesive. (a) Identification. Ethylene oxide homopolymer and/or karaya denture adhesive is a device composed of ethylene oxide homopolymer and/or karaya intended to be...

  19. 21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... carboxymethylcellulose sodium denture adhesive. 872.3410 Section 872.3410 Food and Drugs FOOD AND DRUG ADMINISTRATION....3410 Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive is a...

  20. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ester with pentaerythritol. 721.3680 Section 721.3680 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442)...

  1. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ester with pentaerythritol. 721.3680 Section 721.3680 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442)...

  2. Effect of poly(ethylene oxide) homopolymer and two different poly(ethylene oxide-b-poly(propylene oxide)-b-poly(ethylene oxide) triblock copolymers on morphological, optical, and mechanical properties of nanostructured unsaturated polyester.

    PubMed

    Builes, Daniel H; Hernández-Ortiz, Juan P; Corcuera, Ma Angeles; Mondragon, Iñaki; Tercjak, Agnieszka

    2014-01-22

    Novel nanostructured unsaturated polyester resin-based thermosets, modified with poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), and two poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) block copolymers (BCP), were developed and analyzed. The effects of molecular weights, blocks ratio, and curing temperatures on the final morphological, optical, and mechanical properties were reported. The block influence on the BCP miscibility was studied through uncured and cured mixtures of unsaturated polyester (UP) resins with PEO and PPO homopolymers having molecular weights similar to molecular weights of the blocks of BCP. The final morphology of the nanostructured thermosetting systems, containing BCP or homopolymers, was investigated, and multiple mechanisms of nanostructuration were listed and explained. By considering the miscibility of each block before and after curing, it was determined that the formation of the nanostructured matrices followed a self-assembly mechanism or a polymerization-induced phase separation mechanism. The miscibility between PEO or PPO blocks with one of two phases of UP matrix was highlighted due to its importance in the final thermoset properties. Relationships between the final morphology and thermoset optical and mechanical properties were examined. The mechanisms and physics behind the morphologies lead toward the design of highly transparent, nanostructured, and toughened thermosetting UP systems. PMID:24354274

  3. Clinorotation affects morphology and ethylene production in soybean seedlings

    NASA Technical Reports Server (NTRS)

    Hilaire, E.; Peterson, B. V.; Guikema, J. A.; Brown, C. S.; Sager, J. C. (Principal Investigator)

    1996-01-01

    The microgravity environment of spaceflight influences growth, morphology and metabolism in etiolated germinating soybean. To determine if clinorotation will similarly impact these processes, we conducted ground-based studies in conjunction with two space experiment opportunities. Soybean (Glycine max [L.] Merr.) seeds were planted within BRIC (Biological Research In Canister) canisters and grown for seven days at 20 degrees C under clinorotation (1 rpm) conditions or in a stationary upright mode. Gas samples were taken daily and plants were harvested after seven days for measurement of growth and morphology. Compared to the stationary upright controls, plants exposed to clinorotation exhibited increased root length (125% greater) and fresh weight (42% greater), whereas shoot length and fresh weight decreased by 33% and 16% respectively. Plants grown under clinorotation produced twice as much ethylene as the stationary controls. Seedlings treated with triiodo benzoic acid (TIBA), an auxin transport inhibitor, under clinorotation produced 50% less ethylene than the untreated control subjected to the same gravity treatment, whereas a treatment with 2,4-D increased ethylene by five-fold in the clinorotated plants. These data suggest that slow clinorotation influences biomass partitioning and ethylene production in etiolated soybean plants.

  4. Polymerization of Ethylene Oxide, Propylene Oxide, and Other Alkylene Oxides: Synthesis, Novel Polymer Architectures, and Bioconjugation.

    PubMed

    Herzberger, Jana; Niederer, Kerstin; Pohlit, Hannah; Seiwert, Jan; Worm, Matthias; Wurm, Frederik R; Frey, Holger

    2016-02-24

    The review summarizes current trends and developments in the polymerization of alkylene oxides in the last two decades since 1995, with a particular focus on the most important epoxide monomers ethylene oxide (EO), propylene oxide (PO), and butylene oxide (BO). Classical synthetic pathways, i.e., anionic polymerization, coordination polymerization, and cationic polymerization of epoxides (oxiranes), are briefly reviewed. The main focus of the review lies on more recent and in some cases metal-free methods for epoxide polymerization, i.e., the activated monomer strategy, the use of organocatalysts, such as N-heterocyclic carbenes (NHCs) and N-heterocyclic olefins (NHOs) as well as phosphazene bases. In addition, the commercially relevant double-metal cyanide (DMC) catalyst systems are discussed. Besides the synthetic progress, new types of multifunctional linear PEG (mf-PEG) and PPO structures accessible by copolymerization of EO or PO with functional epoxide comonomers are presented as well as complex branched, hyperbranched, and dendrimer like polyethers. Amphiphilic block copolymers based on PEO and PPO (Poloxamers and Pluronics) and advances in the area of PEGylation as the most important bioconjugation strategy are also summarized. With the ever growing toolbox for epoxide polymerization, a "polyether universe" may be envisaged that in its structural diversity parallels the immense variety of structural options available for polymers based on vinyl monomers with a purely carbon-based backbone. PMID:26713458

  5. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.3700 Fatty acid, ester with styrenated phenol... chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  6. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.3700 Fatty acid, ester with styrenated phenol... chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  7. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.3700 Fatty acid, ester with styrenated phenol... chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  8. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.3700 Fatty acid, ester with styrenated phenol... chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  9. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.3700 Fatty acid, ester with styrenated phenol... chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  10. Ethylene signalling is mediating the early cadmium-induced oxidative challenge in Arabidopsis thaliana.

    PubMed

    Schellingen, Kerim; Van Der Straeten, Dominique; Remans, Tony; Vangronsveld, Jaco; Keunen, Els; Cuypers, Ann

    2015-10-01

    Cadmium (Cd) induces the generation of reactive oxygen species (ROS) and stimulates ethylene biosynthesis. The phytohormone ethylene is a regulator of many developmental and physiological plant processes as well as stress responses. Previous research indicated various links between ethylene signalling and oxidative stress. Our results support a correlation between the Cd-induced oxidative challenge and ethylene signalling in Arabidopsis thaliana leaves. The effects of 24 or 72 h exposure to 5 μM Cd on plant growth and several oxidative stress-related parameters were compared between wild-type (WT) and ethylene insensitive mutants (etr1-1, ein2-1, ein3-1). Cadmium-induced responses observed in WT plants were mainly affected in etr1-1 and ein2-1 mutants, of which the growth was less inhibited by Cd exposure as compared to WT and ein3-1 mutants. Both etr1-1 and ein2-1 showed a delayed response in the glutathione (GSH) metabolism, including GSH levels and transcript levels of GSH synthesising and recycling enzymes. Furthermore, the expression of different oxidative stress marker genes was significantly lower in Cd-exposed ein2-1 mutants, evidencing that ethylene signalling is involved in early responses to Cd stress. A model for the cross-talk between ethylene signalling and oxidative stress is proposed. PMID:26398798

  11. Gas Permeation through Polystyrene-Poly(ethylene oxide) Block Copolymers

    NASA Astrophysics Data System (ADS)

    Hallinan, Daniel, Jr.; Minelli, Matteo; Giacinti-Baschetti, Marco; Balsara, Nitash

    2013-03-01

    Lithium air batteries are a potential technology for affordable energy storage. They consist of a lithium metal anode and a porous air cathode separated by a solid polymer electrolyte membrane, such as PEO/LiTFSI (PEO = poly(ethylene oxide), LiTFSI = lithium bis-trifluoromethane sulfonimide). For extended operation of such a battery, the polymer electrolyte must conduct lithium ions while blocking electrons and gases present in air. In order to maintain a pressure difference the membrane must be mechanically robust, which can be achieved by incorporating the PEO into a block copolymer with a glassy block such as PS (PS = polystyrene). To protect the lithium electrode, the membrane must have low permeability to gases in air such as CO2, N2, and O2. We have therefore studied the permeation of pure gases through a PS-PEO block copolymer. A high molecular weight, symmetric block copolymer with a lamellar morphology was used to cast free-standing membranes. Gas permeability was measured through these membranes with a standard, pressure-based technique. A model was developed to account for transport through the polymer membrane consisting of semi-crystalline PEO lamellae and amorphous PS lamellae. PEO crystallinity was extracted from the permeation model and compares well with values from differential scanning calorimetry measurements.

  12. SAMPLING/ANALYTICAL METHOD EVALUATION FOR ETHYLENE OXIDE EMISSION AND CONTROL UNIT EFFICIENCY DETERMINATIONS

    EPA Science Inventory

    Radian Corporation, assisting the Environmental Monitoring Systems Laboratory, Environmental Protection Agency, Research Triangle Park, North Carolina, performed a field evaluation of a method for sampling and analyzing ethylene oxide (EO) in the vent stream from a sterilization ...

  13. Preliminary survey report: control technology for ethylene oxide sterilization at Selby General Hospital, Marietta, Ohio

    SciTech Connect

    Kercher, S.L.; Mortimer, V.D.; Todd, W.F.

    1985-08-01

    A survey of control technology for reducing exposure during ethylene oxide sterilization was conducted at Selby General Hospital, Marietta, Ohio on August 30, 1984. The Central Services Department performed ethylene oxide sterilization for obstetrics, neonatal care, respiratory therapy, cytology, isolation cases, and surgery. Engineering controls consisted of isolation of the sterilizer and aerators, local exhaust ventilation, a continuous fresh air purge on the sterilization cycle, in chamber aeration of the sterilizers, and general exhaust ventilation of the Central Services Department and the sterilizer room. The author concludes that the Central Services Department has instituted control technology that minimizes employee exposure to ethylene-oxide. The hospital should be considered a candidate for an in-depth survey in a NIOSH study of control technology for ethylene oxide sterilization in hospitals.

  14. Ethylene oxide emissions from commercial sterilization/fumigation operations: Background information for proposed standards. Final report

    SciTech Connect

    Not Available

    1993-03-01

    Table of Contents: Ethylene Oxide Sterilization/Fumigation Processes and Emissions; Emission Control Techniques; Regulatory Alternatives; Environmental Impacts; Emission Control Costs, and The Economic Impacts of the Candidate Neshap Controls.

  15. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (Revised Aug 2014 External Review Draft)

    EPA Science Inventory

    EPA is seeking peer review of the scientific basis supporting the human health hazard and dose-response assessment of ethylene oxide (cancer) that will appear in the Integrated Risk Information System (IRIS) database.

  16. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (Revised July 2013 External Review Draft)

    EPA Science Inventory

    EPA is initiating a public comment period prior to peer review of the scientific basis supporting the human health hazard and dose-response assessment of ethylene oxide (cancer) that will appear in the Integrated Risk Information System (IRIS) database.

  17. Fourier Transform Microwave Spectra of CO{2}-ETHYLENE Sulfide, CO{2}-ETHYLENE Oxide and CO{2}-PROPYLENE Oxide Complexes

    NASA Astrophysics Data System (ADS)

    Orita, Yukari; Kawashima, Yoshiyuki; Hirota, Eizi

    2010-06-01

    We have previously examined the difference in roles of O and S in structure and dynamics of the CO-ethylene oxide (EO) and CO-ethylene sulfide (ES) complexes. We have extended the investigation to CO{2}-EO and CO{2}-ES for comparison. We have also observed the CO{2}-propylene oxide (PO) complex, which is an important intermediate in the reaction of PO with CO{2} leading to polycarbonate. Both a-type and b-type transitions were observed for the CO{2}-EO and CO{2}-ES, but no c-type transitions were observed at all. We also detected the {34}S and {13}C isotopic species in natural abundance and the species containing {18}OCO and C{18}O% {2}, which were synthesized by burning paper in an {18}O{2} and{% 16}O{2} mixture. By analyzing the observed spectra we concluded the CO{2} moiety of CO{2}-EO and CO{2}-ES located in a plane % prependicular to the three-membered ring and bisecting the COC or CSC angle of EO or ES, respectively, as in the case of CO-EO and CO-ES complexes. An % ab initio MO calculation at the level of MP2/6-311G(d, p) yielded an optimized structure in good agreement with the experimental result. We have derived from the observed spectra the distance, the stretching force constant, and the binding energy of the bonds between the constituents of the CO{2}-EO and CO{2}-ES complexes and have found that the distances of the two complexes were shorter by 0.2Å than those in CO-EO and CO-ES, respectively, and that the intermolecular bonds were two times stronger in the CO{2} complexes than in the corresponding CO complexes. We have concluded from the observed spectra that the CO{2} moiety in CO{2}-PO is located on the PO three-membered ring plane opposite to the methyl group. The constituents in CO{2}-PO were more weakly bound than those in CO{2}-EO and CO{2}-ES. S. Sato, Y. Kawashima, Y. Tatamitani, and E. Hirota, 63rd International Symposium on Molecular Spectroscopy, WF05 (2008).

  18. Nitric Oxide, Ethylene, and Auxin Cross Talk Mediates Greening and Plastid Development in Deetiolating Tomato Seedlings.

    PubMed

    Melo, Nielda K G; Bianchetti, Ricardo E; Lira, Bruno S; Oliveira, Paulo M R; Zuccarelli, Rafael; Dias, Devisson L O; Demarco, Diego; Peres, Lazaro E P; Rossi, Magdalena; Freschi, Luciano

    2016-04-01

    The transition from etiolated to green seedlings involves the conversion of etioplasts into mature chloroplasts via a multifaceted, light-driven process comprising multiple, tightly coordinated signaling networks. Here, we demonstrate that light-induced greening and chloroplast differentiation in tomato (Solanum lycopersicum) seedlings are mediated by an intricate cross talk among phytochromes, nitric oxide (NO), ethylene, and auxins. Genetic and pharmacological evidence indicated that either endogenously produced or exogenously applied NO promotes seedling greening by repressing ethylene biosynthesis and inducing auxin accumulation in tomato cotyledons. Analysis performed in hormonal tomato mutants also demonstrated that NO production itself is negatively and positively regulated by ethylene and auxins, respectively. Representing a major biosynthetic source of NO in tomato cotyledons, nitrate reductase was shown to be under strict control of both phytochrome and hormonal signals. A close NO-phytochrome interaction was revealed by the almost complete recovery of the etiolated phenotype of red light-grown seedlings of the tomato phytochrome-deficient aurea mutant upon NO fumigation. In this mutant, NO supplementation induced cotyledon greening, chloroplast differentiation, and hormonal and gene expression alterations similar to those detected in light-exposed wild-type seedlings. NO negatively impacted the transcript accumulation of genes encoding phytochromes, photomorphogenesis-repressor factors, and plastid division proteins, revealing that this free radical can mimic transcriptional changes typically triggered by phytochrome-dependent light perception. Therefore, our data indicate that negative and positive regulatory feedback loops orchestrate ethylene-NO and auxin-NO interactions, respectively, during the conversion of colorless etiolated seedlings into green, photosynthetically competent young plants. PMID:26829981

  19. Effects of Kinetin, IAA, and Gibberellin on Ethylene Production, and Their Interactions in Growth of Seedlings.

    PubMed

    Fuchs, Y; Lieberman, M

    1968-12-01

    Kinetin in concentrations of 10(-8) to 10(-4)m, stimulated ethylene production in 3 and 4-day old etiolated seedlings of Alaska pea (Pisum sativum L. var. Alaska). Seedlings of other species responded similarly. The response to kinetin depended on the age of the seedlings.Kinetin alone did not influence ethylene production in 6-day old stem sections, but it greatly increased the enhancing effect of IAA.Gibberellic acid had no effect on ethylene production by pea seedlings during the first 6 days of growth. Ethylene and gibberellic acid are antagonistic in their effects on growth of the seedlings; ethylene interfered severely with the action of gibberellic acid but did not completely suppress it.The inhibitors cycloheximide, cupferron, and N-ethylmaleimide, caused considerable inhibition of kinetin-induced ethylene production but were much less effective in the endogenous ethylene-forming system. PMID:16657004

  20. Novel adhesive properties of poly(ethylene-oxide) adsorbed nanolayers

    NASA Astrophysics Data System (ADS)

    Zeng, Wenduo

    Solid-polymer interfaces play crucial roles in the multidisciplinary field of nanotechnology and are the confluence of physics, chemistry, biology, and engineering. There is now growing evidence that polymer chains irreversibly adsorb even onto weakly attractive solid surfaces, forming a nanometer-thick adsorbed polymer layer ("adsorbed polymer nanolayers"). It has also been reported that the adsorbed layers greatly impact on local structures and properties of supported polymer thin films. In this thesis, I aim to clarify adhesive and tribological properties of adsorbed poly(ethylene-oxide) (PEO) nanolayers onto silicon (Si) substrates, which remain unsolved so far. The adsorbed nanolayers were prepared by the established protocol: one has to equilibrate the melt or dense solution against a solid surface; the unadsorbed chains can be then removed by a good solvent, while the adsorbed chains are assumed to maintain the same conformation due to the irreversible freezing through many physical solid-segment contacts. I firstly characterized the formation process and the surface/film structures of the adsorbed nanolayers by using X-ray reflectivity, grazing incidence X-ray diffraction, and atomic force microscopy. Secondly, to compare the surface energy of the adsorbed layers with the bulk, static contact angle measurements with two liquids (water and glycerol) were carried out using a optical contact angle meter equipped with a video camera. Thirdly, I designed and constructed a custom-built adhesion-testing device to quantify the adhesive property. The experimental results provide new insight into the microscopic structure - macroscopic property relationship at the solid-polymer interface.

  1. Interaction of poly(ethylene oxide) with fumed silica.

    PubMed

    Voronin, E F; Gun'ko, V M; Guzenko, N V; Pakhlov, E M; Nosach, L V; Leboda, R; Skubiszewska-Zieba, J; Malysheva, M L; Borysenko, M V; Chuiko, A A

    2004-11-15

    Interaction of poly(ethylene oxide) (PEO, 600 kDa) with fumed silica A-300 (SBET = 316 m2/g) was investigated under different conditions using adsorption, infrared (IR), thermal analysis (TG-DTA), AFM, and quantum chemical methods. The studied dried silica/PEO samples were also carbonized in a flow reactor at 773 K. The structural characteristics of fumed silica, PEO/silica, and pyrocarbon/fumed silica were investigated using nitrogen adsorption-desorption at 77.4 K. PEO adsorption isotherm depicts a high affinity of PEO to the fumed silica surface in aqueous medium. PEO adsorbed in the amount of 50 mg per gram of silica (PEO monolayer corresponds to CPEO approximately 190 mg/g) can disturb approximately 70% of isolated surface silanols. However, at the monolayer coverage, only 20% of oxygen atoms of PEO molecules take part in the hydrogen bonding with the surface silanols. An increase in the PEO amount adsorbed on fumed silica leads to a diminution of the specific surface area and contributions of micro- (pore radius R < 1 nm) and mesopores (1 < R < 25 nm) to the pore volume but contribution of macropores (R > 25 nm) increases with CPEO. Quantum chemical calculations of a complex of a PEO fragment with a tripple bond SiOH group of a silica cluster in the gas phase and with consideration for the solvent (water) effect show a reduction of interaction energy in the aqueous medium. However, the complex remains strong enough to provide durability of the PEO adsorption complexes on fumed silica; i.e., PEO/fumed silica nanocomposites could be stable in both gaseous and liquid media. PMID:15464796

  2. Synthesis of terephthalic acid via Diels-Alder reactions with ethylene and oxidized variants of 5-hydroxymethylfurfural

    PubMed Central

    Pacheco, Joshua J.; Davis, Mark E.

    2014-01-01

    Terephthalic acid (PTA), a monomer in the synthesis of polyethylene terephthalate (PET), is obtained by the oxidation of petroleum-derived p-xylene. There is significant interest in the synthesis of renewable, biomass-derived PTA. Here, routes to PTA starting from oxidized products of 5-hydroxymethylfurfural (HMF) that can be produced from biomass are reported. These routes involve Diels-Alder reactions with ethylene and avoid the hydrogenation of HMF to 2,5-dimethylfuran. Oxidized derivatives of HMF are reacted with ethylene over solid Lewis acid catalysts that do not contain strong Brønsted acids to synthesize intermediates of PTA and its equally important diester, dimethyl terephthalate (DMT). The partially oxidized HMF, 5-(hydroxymethyl)furoic acid (HMFA), is reacted with high pressure ethylene over a pure-silica molecular sieve containing framework tin (Sn-Beta) to produce the Diels-Alder dehydration product, 4-(hydroxymethyl)benzoic acid (HMBA), with 31% selectivity at 61% HMFA conversion after 6 h at 190 °C. If HMFA is protected with methanol to form methyl 5-(methoxymethyl)furan-2-carboxylate (MMFC), MMFC can react with ethylene in the presence of Sn-Beta for 2 h to produce methyl 4-(methoxymethyl)benzenecarboxylate (MMBC) with 46% selectivity at 28% MMFC conversion or in the presence of a pure-silica molecular sieve containing framework zirconium (Zr-Beta) for 6 h to produce MMBC with 81% selectivity at 26% MMFC conversion. HMBA and MMBC can then be oxidized to produce PTA and DMT, respectively. When Lewis acid containing mesoporous silica (MCM-41) and amorphous silica, or Brønsted acid containing zeolites (Al-Beta), are used as catalysts, a significant decrease in selectivity/yield of the Diels-Alder dehydration product is observed. PMID:24912153

  3. Synthesis of terephthalic acid via Diels-Alder reactions with ethylene and oxidized variants of 5-hydroxymethylfurfural.

    PubMed

    Pacheco, Joshua J; Davis, Mark E

    2014-06-10

    Terephthalic acid (PTA), a monomer in the synthesis of polyethylene terephthalate (PET), is obtained by the oxidation of petroleum-derived p-xylene. There is significant interest in the synthesis of renewable, biomass-derived PTA. Here, routes to PTA starting from oxidized products of 5-hydroxymethylfurfural (HMF) that can be produced from biomass are reported. These routes involve Diels-Alder reactions with ethylene and avoid the hydrogenation of HMF to 2,5-dimethylfuran. Oxidized derivatives of HMF are reacted with ethylene over solid Lewis acid catalysts that do not contain strong Brønsted acids to synthesize intermediates of PTA and its equally important diester, dimethyl terephthalate (DMT). The partially oxidized HMF, 5-(hydroxymethyl)furoic acid (HMFA), is reacted with high pressure ethylene over a pure-silica molecular sieve containing framework tin (Sn-Beta) to produce the Diels-Alder dehydration product, 4-(hydroxymethyl)benzoic acid (HMBA), with 31% selectivity at 61% HMFA conversion after 6 h at 190 °C. If HMFA is protected with methanol to form methyl 5-(methoxymethyl)furan-2-carboxylate (MMFC), MMFC can react with ethylene in the presence of Sn-Beta for 2 h to produce methyl 4-(methoxymethyl)benzenecarboxylate (MMBC) with 46% selectivity at 28% MMFC conversion or in the presence of a pure-silica molecular sieve containing framework zirconium (Zr-Beta) for 6 h to produce MMBC with 81% selectivity at 26% MMFC conversion. HMBA and MMBC can then be oxidized to produce PTA and DMT, respectively. When Lewis acid containing mesoporous silica (MCM-41) and amorphous silica, or Brønsted acid containing zeolites (Al-Beta), are used as catalysts, a significant decrease in selectivity/yield of the Diels-Alder dehydration product is observed. PMID:24912153

  4. Oxidation induced decomposition of ethylene carbonate from DFT calculations--importance of explicitly treating surrounding solvent.

    PubMed

    Xing, Lidan; Borodin, Oleg

    2012-10-01

    The oxidation induced reactions of the common lithium battery electrolyte solvent ethylene carbonate (EC) have been investigated for EC(2) using density functional theory and for selected reaction paths using Møller-Plesset perturbation theory (MP4). The importance of explicitly treating at least one solvent molecule interacting with EC during oxidation (removal of an electron) on the EC oxidation potential and decomposition reactions was shown by comparing oxidation of EC and EC(2). Accuracy of DFT results was evaluated by comparing with MP4 and G4 values for oxidation of EC. The polarized continuum model (PCM) was used to implicitly include the rest of the surrounding solvent. The oxidation potentials of EC(2) and EC(4) were found to be significantly lower than the intrinsic oxidation potential of an isolated EC and also lower than the oxidation potential of EC-BF(4)(-). The exothermic proton abstraction from the ethylene group of EC by the carbonyl group of another EC was responsible for the decreased oxidative stability of EC(2) and EC(4) compared to EC. The most exothermic path with the smallest barrier for EC(2) oxidation yielded CO(2) and an ethanol radical cation. The reaction paths with the higher barrier yielded oligo(ethylene carbonate) suggesting a pathway for the experimentally observed poly(ethylene carbonate) formation of EC-based electrolytes at cathode surfaces. PMID:22885926

  5. Study on thermodynamics and oxidation mechanism of ethylene glycol in the preparation of nanometer nickel powders

    SciTech Connect

    Jin Shengming . E-mail: shmjin@mail.csu.edu.cn; Yuan Liangsheng; Zhou Ying; Qiu Guanzhou; Wan Cuifeng

    2006-11-09

    Nanometer nickel powders have been prepared using the polyol method with NaOH, Ni(NO{sub 3}){sub 2}.6H{sub 2}O, ethylene glycol (EG), and polyvinylpyrrolidone (PVP) as raw materials. The thermodynamics of the reaction system was studied, and the E-pH diagram of Ni-EG-H{sub 2}O was plotted. The oxidation products of EG were predicted from the E-pH diagram, and CO{sub 3} {sup 2-} in alkaline solutions was identified as the product through the IR spectrum and CaCO{sub 3} sediment. Field-emission scanning electron micrograph (FE-SEM) showed that spherical nanometer nickel powders were obtained.

  6. Micellization of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers in aqueous solutions: Thermodynamics of copolymer association

    SciTech Connect

    Alexandridis, P.; Hatton, T.A. . Dept. of Chemical Engineering); Holzwarth, J.F. )

    1994-04-25

    The critical micellization temperature (cmt) and critical micellization concentration (cmc) values of 12 Pluronic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymers, covering a wide range of molecular weights (2,900--14,600) and PPO/PEO ratios (0.19--1.79), were determined employing a dye solubilization method. A closed association model was found to describe adequately the copolymer micellization process for the majority of the Pluronics and used to obtain the standard free energies ([Delta]G[degree]), enthalpies ([Delta]H[degree]), and entropies ([Delta]S[degree]) of micellization. It was determined that the micellization process is entropy-driven and has an endothermic micellization enthalpy. The hydrophobic part of the Pluronics, PPO, was responsible for the micellization, apparently due to diminishing hydrogen bonding between water and PPO with increasing temperature. The cmc dependence on temperature and size of headgroup (PEO) of Pluronics follows a similar trend with lower molecular weight C[sub i]E[sub j] nonionic surfactants, the effect of temperature being more pronounced with the Pluronics. The PEO-PPO-PEO block copolymers were compared to PPO-PEO-PPO block and PEO-PPO random copolymers, in an attempt to probe the effect of molecular architecture in the formation of micelles. No micelles were observed in aqueous PPO-PEO-PPO block copolymer solutions with increasing temperature, up to the cloud point.

  7. Crystallization behaviour of poly(ethylene oxide) under confinement in the electrospun nanofibers of polystyrene/poly(ethylene oxide) blends.

    PubMed

    Samanta, Pratick; V, Thangapandian; Singh, Sajan; Srivastava, Rajiv; Nandan, Bhanu; Liu, Chien-Liang; Chen, Hsin-Lung

    2016-06-21

    We have studied the confined crystallization behaviour of poly(ethylene oxide) (PEO) in the electrospun nanofibers of the phase-separated blends of polystyrene (PS) and PEO, where PS was present as the major component. The size and shape of PEO domains in the nanofibers were considerably different from those in the cast films, presumably because of the nano-dimensions of the nanofibers and the extensional forces experienced by the polymer solution during electrospinning. The phase-separated morphology in turn influenced the crystallization behaviour of PEO in the blend nanofibers. At a PEO weight fraction of ≥0.3, crystallization occurred through a heterogeneous nucleation mechanism similar to that in cast blend films. However, as the PEO weight fraction in the blend nanofibers was reduced from 0.3 to 0.2, an abrupt transformation of the nucleation mechanism from the heterogeneous to predominantly homogenous type was observed. The change in the nucleation mechanism implied a drastic reduction of the spatial continuity of PEO domains in the nanofibers, which was not encountered in the cast film. The melting temperature and crystallinity of the PEO crystallites developed in the nanofibers were also significantly lower than those in the corresponding cast films. The phenomena observed were reconciled by the morphological observation, which revealed that the phase separation under the radial constraint of the nanofibers led to the formation of small-sized fibrillar PEO domains with limited spatial connectivity. The thermal treatment of the PS/PEO blend nanofibers above the glass transition temperature of PS induced an even stronger confinement effect on PEO crystallization. PMID:27184694

  8. Features of anodic niobium oxide formation in aqueous-organic electrolyte solutions (influence of ethylene glycol)

    SciTech Connect

    Bairachnyi, B.I.; Gomozov, V.P.; Lyashok, L.V.; Glagolev, S.E.

    1992-02-10

    The formation of anodic oxide films (AOFs) on valve metals in electrolytes with different compositions has received little attention. Earlier investigations dealt mainly with AOF growth and properties in aqueous solutions of mineral and organic acids and salts. Less research was done on electrolytes containing aqueous-organic solvents. An empirically formulated electrolyte with a water/ethylene glycol mixture as the solvent is widely employed in forming the dielectric for semiconductor oxide capacitors (SOCs). The mechanism by which ethylene glycol acts on AOF properties is still not wholly clear. It has been found that AOFs produced in an ethylene glycol electrolyte are bilaminar, with the outer layer being less corrosion-resistant. The degradation resistance and crystalline phase content of AOFs have also been studied. The objective of the present study was to examine the effect of ethylene glycol as solvent on AOF formation on niobium.

  9. Poly(cyclohexylethylene)-block-poly(ethylene oxide) block polymers for metal oxide templating

    SciTech Connect

    Schulze, Morgan W.; Sinturel, Christophe

    2015-09-01

    A series of poly(cyclohexylethylene)-block-poly(ethylene oxide) (CEO) diblock copolymers were synthesized through tandem anionic polymerizations and heterogeneous catalytic hydrogenation. Solvent-annealed CEO diblock films were used to template dense arrays of inorganic oxide nanodots via simple spin coating of an inorganic precursor solution atop the ordered film. The substantial chemical dissimilarity of the two blocks enables (i) selective inclusion of the inorganic precursor within the PEO domain and (ii) the formation of exceptionally small feature sizes due to a relatively large interaction parameter estimated from mean-field analysis of the order–disorder transition temperatures of compositionally symmetric samples. UV/ozone treatment following incorporation produces an ordered arrangement of oxide nanodots and simultaneously removes the block polymer template. However, we report the smallest particles (6 ± 1 nm) templated from a selective precursor insertion method to date using a block polymer scaffold.

  10. Poly(cyclohexylethylene)-block-poly(ethylene oxide) block polymers for metal oxide templating

    DOE PAGESBeta

    Schulze, Morgan W.; Sinturel, Christophe; Hillmyer, Marc A.

    2015-09-01

    A series of poly(cyclohexylethylene)-block-poly(ethylene oxide) (CEO) diblock copolymers were synthesized through tandem anionic polymerizations and heterogeneous catalytic hydrogenation. Solvent-annealed CEO diblock films were used to template dense arrays of inorganic oxide nanodots via simple spin coating of an inorganic precursor solution atop the ordered film. The substantial chemical dissimilarity of the two blocks enables (i) selective inclusion of the inorganic precursor within the PEO domain and (ii) the formation of exceptionally small feature sizes due to a relatively large interaction parameter estimated from mean-field analysis of the order–disorder transition temperatures of compositionally symmetric samples. UV/ozone treatment following incorporation produces anmore » ordered arrangement of oxide nanodots and simultaneously removes the block polymer template. However, we report the smallest particles (6 ± 1 nm) templated from a selective precursor insertion method to date using a block polymer scaffold.« less

  11. Heat of Combustion of the Product Formed by the Reaction of Acetylene, Ethylene, and Diborane

    NASA Technical Reports Server (NTRS)

    Tannenbaum, Stanley

    1957-01-01

    The net heat of combustion of the product formed by the reaction of diborane with a mixture of acetylene and ethylene was found to be 20,440 +/- 150 Btu per pound for the reaction of liquid fuel to gaseous carbon dioxide, gaseous water, and solid boric oxide. The measurements were made in a Parr oxygen-bomb calorimeter, and the combustion was believed to be 98 percent complete. The estimated net-heat of combustion for complete combustion would therefore be 20,850 +/- 150 Btu per pound.

  12. Ethylene promotes germination of Arabidopsis seed under salinity by decreasing reactive oxygen species: evidence for the involvement of nitric oxide simulated by sodium nitroprusside.

    PubMed

    Lin, Yingchao; Yang, Lei; Paul, Matthew; Zu, Yuangang; Tang, Zhonghua

    2013-12-01

    Both ethylene and nitric oxide (NO) are involved in modulating seed germination in adverse environments. However, the mechanisms by which they interact and affect germination have not been explained. In this study, the relationship between ethylene and NO during germination of Arabidopsis seed under salinity was analysed. Application of exogenous 1-aminocyclopropane-1-carboxylate (ACC, a precursor of ethylene biosynthesis) or sodium nitroprusside (SNP, an NO donor) largely overcame the inhibition of germination induced by salinity. The effects of ACC and SNP were decreased by 2-phenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (cPTIO), a specific NO scavenger, or by aminoisobutyric acid (AIB), an inhibitor of ethylene biosynthesis, indicating that ethylene and NO interact during germination under salinity. Further, we demonstrated that ACC increased NO production and that SNP greatly induced the expression of the ACS2 gene involved in ethylene synthesis in Arabidopsis seeds germinating under salinity stress, suggesting that each substance influences the production of the other. Application of exogenous ACC increased germination under oxidative stress induced by hydrogen peroxide (H2O2) while SNP had a much smaller effect on wild-type Arabidopsis (Col-0) and no effect on the ethylene insensitive mutant (ein3-1) seeds, respectively. This shows that NO increased germination under salinity indirectly through H2O2 acting via the ethylene pathway. The endogenous concentration of H2O2 was increased by salinity in germinating seeds but was decreased by exogenous ACC, which stimulated germination ultimately. To explain all these results and the regulation of germination of Arabidopsis seed under salinity we propose a model involving ethylene, NO and H2O2 interaction. PMID:24148906

  13. Study of core-shell platinum-based catalyst for methanol and ethylene glycol oxidation

    NASA Astrophysics Data System (ADS)

    Kaplan, D.; Alon, M.; Burstein, L.; Rosenberg, Yu.; Peled, E.

    A Ru core-Pt shell, XC72-supported catalyst was synthesized in a two-step process: first, by deposition of Ru on XC72 by the polyol process and then by deposition of Pt on the XC72-supported Ru, with NaBH 4 as reducing agent. The structure and composition of this core-shell catalyst were determined by EDS, XPS, TEM and XRD. Electrochemical characterization was determined with the use of cyclic voltammetry and chronoamperometry. The methanol and ethylene glycol oxidation activities of the core-shell catalyst were studied at 80 °C and compared to those of a commercial catalyst. It was found to be significantly better (in terms of A g -1 of Pt) in the case of methanol oxidation and worse in the case of ethylene glycol oxidation. Possible reasons for the lower ethylene glycol oxidation activity of the core-shell catalyst are discussed.

  14. Determination of ethylene oxide in ethoxylated surfactants and demulsifiers by headspace gas chromatography.

    PubMed

    Dahlgran, J R; Shingleton, C R

    1987-01-01

    A headspace gas chromatographic method for the determination of traces of ethylene oxide in ethoxylated surfactants and demulsifiers was developed. Samples are analyzed directly by the technique to a 1.0 ppm (w/w) quantitation limit. The procedure also performs well for propylene oxide, acetaldehyde, and 1,4-dioxane. It is simple, sensitive, and linear. The percent relative standard deviations for 0.5 and 30 ppm ethylene oxide in the surfactant were 2.8 and 8.3%, respectively. PMID:3680111

  15. Miscibility and degradability of poly(lactic acid)poly(ethylene oxide)/poly(ethylene glycol) blends

    SciTech Connect

    Yue, C.L.; Dave, V.; Gross, R.A.; McCarthy, S.P.

    1995-12-01

    Poly(lactic acid) [PLA] was melt blended with polyethylene(oxide) [PEG] and poly(ethylene glycol) [PEG] in different compositions to form blown films. It was determined that PLA was miscible with PEO in all compositions. Based on Gordon-Taylor equation, it was determined that the interactions between PLA and PEO is stronger than PEG. The addition of low molecular weight PEG improved the elongation and tear strength of the blends. Enzymatic degradation results shows that the weight loss of all the samples was more than 80% of the initial weight in 48 hours.

  16. Effect of Organic Capping Layers over Monodisperse Platinum Nanoparticles upon Activity for Ethylene Hydrogenation and Carbon Monoxide Oxidation

    SciTech Connect

    Kuhn, John N.; Tsung, Chia-Kuang; Huang, Wenyu; Somorjai, Gabor A.

    2009-03-24

    The influence of oleylamine (OA), trimethyl tetradecyl ammonium bromide (TTAB), and polyvinlypyrrolidone (PVP) capping agents upon the catalytic properties of Pt/silica catalysts was evaluated. Pt nanoparticles that were 1.5 nm in size were synthesized by the same procedure (ethylene glycol reduction under basic conditions) with the various capping agents added afterward for stabilization. Before examining catalytic properties for ethylene hydrogenation and CO oxidation, the Pt NPs were deposited onto mesoporous silica (SBA-15) supports and characterized by transmission electron microscopy (TEM), H{sub 2} chemisorption, and elemental analysis (ICP-MS). PVP- and TTAB-capped Pt yielded mass-normalized reaction rates that decreased with increasing pretreatment temperature, and this trend was attributed to the partial coverage of the Pt surface with decomposition products from the organic capping agent. Once normalized to the Pt surface area, similar intrinsic activities were obtained regardless of the pretreatment temperature, which indicated no influence on the nature of the active sites. Consequently, a chemical probe technique using intrinsic activity for ethylene hydrogenation was demonstrated as an acceptable method for estimating the metallic surface areas of Pt. Amine (OA) capping exhibited a detrimental influence on the catalytic properties as severe deactivation and low activity were observed for ethylene hydrogenation and CO oxidation, respectively. These results were consistent with amine groups being strong poisons for Pt surfaces, and revealed the need to consider the effects of capping agents on the catalytic properties.

  17. Synthesis of Ethylene and Other Useful Products by Reduction of Carbon Dioxide

    NASA Technical Reports Server (NTRS)

    Rosenberg, Sanders D.; Makel, Darby B.; Finn, John E.

    1998-01-01

    The synthesis of ethylene and other useful products by reduction of carbon dioxide is discussed. The synthesis of ethylene from carbon dioxide has been undertaken. A few different chemical reactions are presented for the production of ethylene. This ethylene can then form the basis for the manufacture of a variety of useful products. It can be used in the preparation of a variety of plastics that can be used for the fabrication of structural materials, and can be used in creating life support systems, which can lead to the development of closed life support systems based on the use of inorganic processes and chemical engineering principles.

  18. Platinum Metal-Free Catalysts for Selective Soft Oxidative Methane → Ethylene Coupling. Scope and Mechanistic Observations.

    PubMed

    Peter, Matthias; Marks, Tobin J

    2015-12-01

    Using abundant soft oxidants, a high methane-to-ethylene conversion might be achievable due to the low thermodynamic driving force for over-oxidation. Here we report on the oxidative coupling of methane by gaseous S2 (SOCM). The catalytic properties of Pd/Fe3O4 are compared with those of Fe3O4, and it is found that high ethylene selectivities can be achieved without noble metals; conversion and selectivity on Fe3O4 are stable for at least 48 h at SOCM conditions. SOCM data for 10 oxides are compared, and ethylene selectivities as high as 33% are found; the C2H4/C2H6 ratios of 9-12 observed at the highest S2 conversions are significantly higher than the C2H4/C2H6 ratios usually found in the CH4 coupling with O2. Complementary in-detail analytical studies show that, on Mg, Zr, Sm, W, and La catalysts, which strongly coke during the reaction, lower ethylene selectivities are observed than on Fe, Ti, and Cr catalysts, which only coke to a minor extent. Further catalyst-dependent changes during SOCM in surface area, surface composition, and partial conversion to oxysulfides and sulfides are discussed. Evidence concerning the reaction mechanism is obtained taking into account the selectivity for the different reaction products versus the contact time. CH4 coupling proceeds non-oxidatively with the evolution of H2 on some catalysts, and evidence is presented that C2H4 and C2H2 formation occur via C2H6 and C2H4 dehydrogenation, respectively. PMID:26551955

  19. Roles of Ethylene Production and Ethylene Receptor Expression in Regulating Apple Fruitlet Abscission.

    PubMed

    Eccher, Giulia; Begheldo, Maura; Boschetti, Andrea; Ruperti, Benedetto; Botton, Alessandro

    2015-09-01

    Apple (Malus × domestica) is increasingly being considered an interesting model species for studying early fruit development, during which an extremely relevant phenomenon, fruitlet abscission, may occur as a response to both endogenous and/or exogenous cues. Several studies were carried out shedding light on the main physiological and molecular events leading to the selective release of lateral fruitlets within a corymb, either occurring naturally or as a result of a thinning treatment. Several studies pointed out a clear association between a rise of ethylene biosynthetic levels in the fruitlet and its tendency to abscise. A direct mechanistic link, however, has not yet been established between this gaseous hormone and the generation of the abscission signal within the fruit. In this work, the role of ethylene during the very early stages of abscission induction was investigated in fruitlet populations with different abscission potentials due either to the natural correlative inhibitions determining the so-called physiological fruit drop or to a well-tested thinning treatment performed with the cytokinin benzyladenine. A crucial role was ascribed to the ratio between the ethylene produced by the cortex and the expression of ethylene receptor genes in the seed. This ratio would determine the final probability to abscise. A working model has been proposed consistent with the differential distribution of four receptor transcripts within the seed, which resembles a spatially progressive cell-specific immune-like mechanism evolved by apple to protect the embryo from harmful ethylene. PMID:25888617

  20. Roles of Ethylene Production and Ethylene Receptor Expression in Regulating Apple Fruitlet Abscission1[OPEN

    PubMed Central

    Eccher, Giulia; Begheldo, Maura; Boschetti, Andrea; Ruperti, Benedetto; Botton, Alessandro

    2015-01-01

    Apple (Malus × domestica) is increasingly being considered an interesting model species for studying early fruit development, during which an extremely relevant phenomenon, fruitlet abscission, may occur as a response to both endogenous and/or exogenous cues. Several studies were carried out shedding light on the main physiological and molecular events leading to the selective release of lateral fruitlets within a corymb, either occurring naturally or as a result of a thinning treatment. Several studies pointed out a clear association between a rise of ethylene biosynthetic levels in the fruitlet and its tendency to abscise. A direct mechanistic link, however, has not yet been established between this gaseous hormone and the generation of the abscission signal within the fruit. In this work, the role of ethylene during the very early stages of abscission induction was investigated in fruitlet populations with different abscission potentials due either to the natural correlative inhibitions determining the so-called physiological fruit drop or to a well-tested thinning treatment performed with the cytokinin benzyladenine. A crucial role was ascribed to the ratio between the ethylene produced by the cortex and the expression of ethylene receptor genes in the seed. This ratio would determine the final probability to abscise. A working model has been proposed consistent with the differential distribution of four receptor transcripts within the seed, which resembles a spatially progressive cell-specific immune-like mechanism evolved by apple to protect the embryo from harmful ethylene. PMID:25888617

  1. Inhibition of ethylene production by putrescine alleviates aluminium-induced root inhibition in wheat plants

    PubMed Central

    Yu, Yan; Jin, Chongwei; Sun, Chengliang; Wang, Jinghong; Ye, Yiquan; Zhou, Weiwei; Lu, Lingli; Lin, Xianyong

    2016-01-01

    Inhibition of root elongation is one of the most distinct symptoms of aluminium (Al) toxicity. Although putrescine (Put) has been identified as an important signaling molecule involved in Al tolerance, it is yet unknown how Put mitigates Al-induced root inhibition. Here, the possible mechanism was investigated by using two wheat genotypes differing in Al resistance: Al-tolerant Xi Aimai-1 and Al-sensitive Yangmai-5. Aluminium caused more root inhibition in Yangmai-5 and increased ethylene production at the root apices compared to Xi Aimai-1, whereas the effects were significantly reversed by ethylene biosynthesis inhibitors. The simultaneous exposure of wheat seedlings to Al and ethylene donor, ethephon, or ethylene biosynthesis precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), increased ethylene production and aggravated root inhibition, which was more pronounced in Xi Aimai-1. In contrast, Put treatment decreased ethylene production and alleviated Al-induced root inhibition in both genotypes, and the effects were more conspicuous in Yangmai-5. Furthermore, our results indicated that Al-induced ethylene production was mediated by ACC synthase (ACS) and ACC oxidase, and that Put decreased ethylene production by inhibiting ACS. Altogether, these findings indicate that ethylene is involved in Al-induced root inhibition and this process could be alleviated by Put through inhibiting ACS activity. PMID:26744061

  2. Permeability and partitioning of ferrocene ethylene oxide and propylene oxide oligomers into electropolymerized films from acetonitrile and polyether solutions

    SciTech Connect

    Pyati, R.; Murray, R.W. )

    1994-10-27

    We report the first electrochemically-based measurements of the rates of small polymer permeation into another polymer. The small polymer permeants are ferrocene ethylene oxide oligomers containing 2, 7, and 16 units and a propylene oxide oligomer containing 3 units. Their permeation into ultrathin microelectrode-supported films of the metal complex polymer poly[Ru(vbpy)[sub 3

  3. Temperature-Dependent Deicing Properties of Electrostatically Anchored Branched Brush Layers of Poly(ethylene oxide).

    PubMed

    Heydari, Golrokh; Tyrode, Eric; Visnevskij, Ceslav; Makuska, Ricardas; Claesson, Per M

    2016-05-01

    The hydration water of hydrophilic polymers freezes at subzero temperatures. The adsorption of such polymers will result in a hydrophilic surface layer that strongly binds water. Provided this interfacial hydration water remains liquidlike at subzero temperatures, its presence could possibly reduce ice adhesion, in particular, if the liquidlike layer is thicker than or comparable to the surface roughness. To explore this idea, a diblock copolymer, having one branched bottle-brush block of poly(ethylene oxide) and one linear cationic block, was electrostatically anchored on flat silica surfaces. The shear ice adhesion strength on such polymer-coated surfaces was investigated down to -25 °C using a homebuilt device. In addition, the temperature dependence of the ice adhesion on surfaces coated with only the cationic block, only the branched bottle-brush block, and with linear poly(ethylene oxide) was investigated. Significant ice adhesion reduction, in particular, at temperatures above -15 °C, was observed on silica surfaces coated with the electrostatically anchored diblock copolymer. Differential scanning calorimetry measurements on bulk polymer solutions demonstrate different thermal transitions of water interacting with branched and linear poly(ethylene oxide) (with hydration water melting points of about -18 and -10 °C, respectively). This difference is consistent with the low shear ice adhesion strength measured on surfaces carrying branched bottle-brush structured poly(ethylene oxide) at -10 °C, whereas no significant adhesion reduction was obtained with linear poly(ethylene oxide) at this temperature. We propose a lubrication effect of the hydration water bound to the branched bottle-brush structured poly(ethylene oxide), which, in the bulk, does not freeze until -18 °C. PMID:27064661

  4. Self-Assembly in a Mixture of Two Poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) Copolymers in Water

    PubMed

    Zhou; Alexandridis; Khan

    1996-11-10

    The self-assembly behavior in water of a mixture of two poly (ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) copolymers, (EO)13(PO)30(EO)13 (L64) and (EO)37(PO)58(EO)37 (P105), was explored at 25°C. The phase boundaries were established using 2H-NMR and inspection under polarized light; the structure of the various lyotropic liquid crystalline (LLC) phases was determined with small-angle X-ray scattering, while viscosity and differential scanning calorimetry measurements were used to probe the isotropic water-rich solution region. Isotropic regions, similar to the neat polymers, are stable at high polymer content. The addition of water induces structure in the amphiphilic block copolymer system. An extended lamellar (D) LLC phase is formed at 20-25% water content; a hexagonal (E) and a cubic (I) LLC phases supersede D at higher water contents. In addition to the above, a narrow isotropic region (L') is observed on the L64-water binary axis, in equilibrium with the E and the D phases. The hexagonal and lamellar LLC phases extended all the way from the L64-rich to the P105-rich side of the ternary L64-P105-water phase diagram; the characteristic hexagonal and lamellar structural dimensions varied linearly with P105 content in the L64-P105 mixture at a constant water concentration. An isotropic (micellar) solution phase (L1) dominates the high-water content corner of the ternary phase diagram. Viscosity measurements in this region provided evidence for increased interactions between the micelles as the boundary to the LLC phases was approached. PMID:8954676

  5. A Nanoarchitecture Based on Silver and Copper Oxide with an Exceptional Response in the Chlorine-Promoted Epoxidation of Ethylene.

    PubMed

    Ramirez, Adrian; Hueso, Jose L; Suarez, Hugo; Mallada, Reyes; Ibarra, Alfonso; Irusta, Silvia; Santamaria, Jesus

    2016-09-01

    The selective oxidation of ethylene to ethylene epoxide is highly challenging as a result of competing reaction pathways leading to the deep oxidation of both ethylene and ethylene oxide. Herein we present a novel catalyst based on silver and copper oxide with an excellent response in the selective oxidation pathway towards ethylene epoxide. The catalyst is composed of different silver nanostructures dispersed on a tubular copper oxide matrix. This type of hybrid nanoarchitecture seems to facilitate the accommodation of chlorine promoters, leading to high yields at low reaction temperatures. The stability after the addition of chlorine promoters implies a substantial improvement over the industrial practice: a single pretreatment step at ambient pressure suffices in contrast with the common practice of continuously feeding organochlorinated precursors during the reaction. PMID:27404950

  6. Effects of brassinosteroid, auxin, and cytokinin on ethylene production in Arabidopsis thaliana plants

    PubMed Central

    Arteca, Richard N.; Arteca, Jeannette M.

    2008-01-01

    Inflorescence stalks produced the highest amount of ethylene in response to IAA as compared with other plant parts tested. Leaf age had an effect on IAA-induced ethylene with the youngest leaves showing the greatest stimulation. The highest amount of IAA-induced ethylene was produced in the root or inflorescence tip with regions below this producing less. Inflorescence stalks treated with IAA, 2,4-D, or NAA over a range of concentrations exhibited an increase in ethylene production starting at 1 μM with increasingly greater responses up to 100 μM, followed by a plateau at 500 μM and a significant decline at 1000 μM. Both 2,4-D and NAA elicited a greater response than IAA at all concentrations tested in inflorescence stalks. Inflorescence leaves treated with IAA, 2,4-D, or NAA exhibited the same trend as inflorescence stalks. However, they produced significantly less ethylene. Inflorescence stalks and leaves treated with 100 μM IAA exhibited a dramatic increase in ethylene production 2 h following treatment initiation. Inflorescence stalks showed a further increase 4 h following treatment initiation and no further increase at 6 h. However, there was a slight decline between 6 h and 24 h. Inflorescence leaves exhibited similar rates of IAA-induced ethylene between 2 h and 24 h. Light and high temperature caused a decrease in IAA-induced ethylene in both inflorescence stalks and leaves. Three auxin-insensitive mutants were evaluated for their inflorescence's responsiveness to IAA. aux2 did not produce ethylene in response to 100 μM IAA, while axr1-3 and axr1-12 showed reduced levels of IAA-induced ethylene as compared with Columbia wild type. Inflorescences treated with brassinolide alone had no effect on ethylene production. However, when brassinolide was used in combination with IAA there was a dramatic increase in ethylene production above the induction promoted by IAA alone. PMID:18583350

  7. Atmospheric chemistry of toxic contaminants 2. Saturated aliphatics: Acetaldehyde, dioxane, ethylene glycol ethers, propylene oxide

    SciTech Connect

    Grosjean, D. )

    1990-11-01

    Detailed mechanisms are outlined for the chemical reactions that contribute to in-situ formation and atmospheric removal of the saturated aliphatic contaminants acetaldehyde, dioxane, ethylene glycol ethers (methyl, ethyl, n-butyl) and propylene oxide. In-situ formation is of major importance for acetaldehyde. In-situ removal involves reaction with OH (all compounds) and, for acetaldehyde, photolysis and reaction with NO{sub 3}. Acetaldehyde, dioxane, and the ethers are rapidly removed (half-lives of less than one day), leading to PAN (acetaldehyde) and to 2-oxodioxane and formaldehyde (dioxane). Reaction products of the glycol ethers include a large number of hydroxyesters, hydroxyacids, and hydroxycarbonyls. Propylene oxide reacts only slowly with OH, with an atmospheric half-life of 3 - 10 days, to yeild formaldehyde, acetaldehyde, and PAN. Uncertainties in the reaction mechanisms for dioxane, the glycol ethers, and propylene oxide are discussed and include C-C vs C-O bond scission in alkoxy radicals as well as alkoxy radical unimolecular decomposition vs reaction with oxygen.

  8. Citric Acid-Modified Fenton's Reaction for the Oxidation of Chlorinated Ethylenes in Soil Solution Systems

    SciTech Connect

    Seol, Yongkoo; Javandel, Iraj

    2008-03-15

    Fenton's reagent, a solution of hydrogen peroxide and ferrous iron catalyst, is used for an in-situ chemical oxidation of organic contaminants. Sulfuric acid is commonly used to create an acidic condition needed for catalytic oxidation. Fenton's reaction often involves pressure buildup and precipitation of reaction products, which can cause safety hazards and diminish efficiency. We selected citric acid, a food-grade substance, as an acidifying agent to evaluate its efficiencies for organic contaminant removal in Fenton's reaction, and examined the impacts of using citric acid on the unwanted reaction products. A series of batch and column experiments were performed with varying H{sub 2}O{sub 2} concentrations to decompose selected chlorinated ethylenes. Either dissolved iron from soil or iron sulfate salt was added to provide the iron catalyst in the batch tests. Batch experiments revealed that both citric and sulfuric acid systems achieved over 90% contaminant removal rates, and the presence of iron catalyst was essential for effective decontamination. Batch tests with citric acid showed no signs of pressure accumulation and solid precipitations, however the results suggested that an excessive usage of H{sub 2}O{sub 2} relative to iron catalysts (Fe{sup 2+}/H{sub 2}O{sub 2} < 1/330) would result in lowering the efficiency of contaminant removal by iron chelations in the citric acid system. Column tests confirmed that citric acid could provide suitable acidic conditions to achieve higher than 55% contaminant removal rates.

  9. Process for the production of ethylene and other hydrocarbons from coal

    SciTech Connect

    Steinberg, M.; Fallon, P.

    1986-01-07

    This patent describes a process for the production of ethylene from coal in commercially significant yields greater than 10% (% carbon converted to product) including the steps of: (a) reacting coal particulates entrained in a flow of gas consisting essentially of methane with the methane gas at a temperature in the approximate range of 850 degrees C to 1000 degrees C and at a partial pressure of approximately 50 psi for a period of time of approximately 1.5 seconds; and (b) recovering ethylene gas produced in the reaction from the product stream consisting of the methane and other reaction products in addition to the ethylene.

  10. MUTATION AND ENHANCED VIRUS TRANSFORMATION OF CULTURED HAMSTER CELLS BY EXPOSURE TO GASEOUS ETHYLENE OXIDE

    EPA Science Inventory

    Ethylene oxide is a classical mutagen and a carcinogen based on evidence from studies in experimental animals. It is widely distributed in industrial, research, hospital, and food environments. In an effort to explore the use of newly developed methods for exposing mammalian cell...

  11. Synthesis of Monodispersed Tantalum(V) oxide Nanospheres by an Ethylene Glycol Mediated Route

    EPA Science Inventory

    Tantalum(V) oxide (Ta2O5) nanospheres have been synthesized by a very simple ethylene glycol mediated route. The two-step process involves the formation of glycolate nanoparticles and their subsequent hydrolysis and calcination to generate the final Ta2O5 nanospheres. The synthes...

  12. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (Interagency Science Discussion Draft)

    EPA Science Inventory

    On September 22, 2006, the draft Evaluation of the Carinogenicity of Ethylene Oxide (EPA/635/R-06/003) and the draft charge to external peer reviewers were released for external peer review and public comment. This draft was reviewed by EPA’s Science Advisory Board (SAB)...

  13. 40 CFR 721.7000 - Polymer of disodium maleate, allyl ether, and ethylene oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Polymer of disodium maleate, allyl... New Uses for Specific Chemical Substances § 721.7000 Polymer of disodium maleate, allyl ether, and... substance identified generically as a polymer of disodium maleate, allyl ether, and ethylene oxide...

  14. 40 CFR 721.7000 - Polymer of disodium maleate, allyl ether, and ethylene oxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Polymer of disodium maleate, allyl... New Uses for Specific Chemical Substances § 721.7000 Polymer of disodium maleate, allyl ether, and... substance identified generically as a polymer of disodium maleate, allyl ether, and ethylene oxide...

  15. 40 CFR 721.7000 - Polymer of disodium maleate, allyl ether, and ethylene oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Polymer of disodium maleate, allyl... New Uses for Specific Chemical Substances § 721.7000 Polymer of disodium maleate, allyl ether, and... substance identified generically as a polymer of disodium maleate, allyl ether, and ethylene oxide...

  16. 78 FR 46260 - Sorbitan Monooleate Ethylene Oxide Adduct; Exemption From the Requirement of a Tolerance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-31

    ... monooleate ethylene oxide adduct is low; the LD 50 was >25,000 mg/kg in the rat and mouse. Also, no systemic... considered nonmutagenic. Evidence of carcinogenicity was not observed in mice. In rats, the incidence of... studies in rats and mice. Also, toxicity was only observed at doses (>10,000 mg/kg/day) well above...

  17. 40 CFR 721.7000 - Polymer of disodium maleate, allyl ether, and ethylene oxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymer of disodium maleate, allyl... New Uses for Specific Chemical Substances § 721.7000 Polymer of disodium maleate, allyl ether, and... substance identified generically as a polymer of disodium maleate, allyl ether, and ethylene oxide...

  18. SIMULATING THE IN-SITU OXIDATIVE TREATMENT OF CHLORINATED ETHYLENES BY POTASSIUM PERMANGANATE

    EPA Science Inventory

    In recent years, MnO{sub}4 oxidation of chlorinated ethylenes (PCE, TCE, and DCE) has emerged as a potentially useful approach for destroying these componds in water. Recently, more applied studies have looked at whether KMnO{sub}4 could be used in remediating sites contaminated ...

  19. 40 CFR 721.7000 - Polymer of disodium maleate, allyl ether, and ethylene oxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Polymer of disodium maleate, allyl... New Uses for Specific Chemical Substances § 721.7000 Polymer of disodium maleate, allyl ether, and... substance identified generically as a polymer of disodium maleate, allyl ether, and ethylene oxide...

  20. Ethylene production associated with petal senescence in carnation flowers is induced irrespective of the gynoecium.

    PubMed

    Ichimura, Kazuo; Niki, Tomoko

    2014-11-15

    To clarify whether climacteric-like increases in ethylene production of senescing petals are also induced in the absence of the gynoecium in cut carnation (Dianthus caryophyllus cv. Barbara) flowers, we compared ethylene production and expression of ethylene-biosynthesis genes in detached petals and in petals, which remained on flowers (attached petals). No significant difference in longevity was observed between the attached and detached petals when held in distilled water, and both showed the inward rolling typical of senescing flowers. Treatment with silver thiosulfate complex (STS), an ethylene inhibitor, similarly delayed senescence of attached and detached petals. Climacteric-like increases in ethylene production of petals and gynoecium started on the same day, with similar bursts in attached and detached petals. Transcript levels of DcACS1 and DcACO1 were very low at harvest and increased similarly during senescence in both petal groups. Removal of the gynoecium did not significantly delay wilting of attached petals. In flowers with the gynoecium removed, the petals produced most of the ethylene while production by the other floral organs was very low, suggesting that wound-induced ethylene is not the reason for the ineffectiveness of gynoecium-removal in inhibiting flower senescence. These results indicate that ethylene biosynthesis is induced in carnation petals irrespective of the gynoecium. PMID:25209694

  1. Ethylene production and its effect on storage respiration rate in wounded and unwounded sugarbeet roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ethylene is produced by all seed plants and stimulates respiration in most plant tissues and organs. To understand how this plant hormone may affect postharvest sugarbeet root respiration, a series of experiments were conducted to determine (1) the rate of ethylene production in wounded and unwound...

  2. A Cuvette Design for Measurement of Ethylene Production and Carbon Dioxide Exchange by Intact Shoots under Controlled Environmental Conditions 1

    PubMed Central

    Bassi, Pawan K.; Spencer, Mary S.

    1979-01-01

    A cuvette is described for simultaneous measurement of ethylene production and CO2 fixation by intact shoots under controlled environmental conditions. This design overcomes potential problems associated with closed systems conventionally used for studies on ethylene production, allowing accurate determination of rates of ethylene production in plants exposed to different environmental conditions. PMID:16660994

  3. Microviscosity in Pluronic and Tetronic poly(ethylene oxide)-poly(propylene oxide) block copolymer micelles

    SciTech Connect

    Nivaggioli, T.; Tsao, B.; Alexandridis, P.; Hatton, T.A. )

    1995-01-01

    The micellar microviscosity afforded by Pluronic and Tetronic poly(ethylene oxide)-poly(propylene oxide) block copolymer aqueous solutions has been investigated by fluorescence and NMR spectroscopy. Comparison is made with bulk poly(propylene oxide) (PPO) samples of different molecular weights. The microviscosity in Pluronic PEO-PPO-PEO copolymer micelles is much larger than that observed in conventional surfactant micelles and depends strongly on the size of the hydrophobic PPO block: the larger this block, the higher the viscosity. Above the critical micellar temperature (CMT), as temperature increases, the microviscosity decreases. However, this decrease is not as important as that observed in bulk PPO. Hence, the relative microviscosity, defined as the ratio of the two observed phenomena, increases. This suggests structural transformation of the micelles resulting in a core becoming more and more compact as temperature increases. Such results have been confirmed by NMR studies that showed broadening of the PPO peak and relatively constant spin-lattice relaxation time, T[sub i], with increasing temperature while the PEO signal remained relatively sharp with an exponential increase in T[sub 1]. 30 refs., 9 figs., 1 tab.

  4. Solubilization of docetaxel in poly(ethylene oxide)-block-poly(butylene/styrene oxide) micelles.

    PubMed

    Elsabahy, Mahmoud; Perron, Marie-Eve; Bertrand, Nicolas; Yu, Ga-Er; Leroux, Jean-Christophe

    2007-07-01

    Poly(ethylene oxide)-block-poly(styrene oxide) (PEO-b-PSO) and PEO-b-poly(butylene oxide) (PEO-b-PBO) of different chain lengths were synthesized and characterized for their self-assembling properties in water by dynamic/static light scattering, spectrofluorimetry, and transmission electron microscopy. The resulting polymeric micelles were evaluated for their ability to solubilize and protect the anticancer drug docetaxel (DCTX) from degradation. The drug release kinetics as well as the cytotoxicity of the loaded micelles were assessed in vitro. All polymers formed micelles with a highly viscous core at low critical association concentrations (<10 mg/L). Micelle morphology depended on the nature of the hydrophobic block, with PBO- and PSO-based micelles yielding monodisperse spherical and cylindrical nanosized aggregates, respectively. The maximum solubilization capacity for DCTX ranged from 0.7 to 4.2% and was the highest for PSO micelles exhibiting the longest hydrophobic segment. Despite their high affinity for DCTX, PEO-b-PSO micelles were not able to efficiently protect DCTX against hydrolysis under accelerated stability testing conditions. Only PEO-b-PBO bearing 24 BO units afforded significant protection against degradation. In vitro, DCTX was released slower from the latter micelles, but all formulations possessed a similar cytotoxic effect against PC-3 prostate cancer cells. These data suggest that PEO-b-P(SO/BO) micelles could be used as alternatives to conventional surfactants for the solubilization of taxanes. PMID:17579476

  5. Thermo-oxidative stability of electron beam irradiated ethylene norbornene copolymer

    NASA Astrophysics Data System (ADS)

    Aymes-Chodur, Caroline; Sghaïer, M.; Yagoubi, N.

    2016-01-01

    The effect of ionizing radiation on the thermal stability of ethylene norbornene copolymer (ENC) to which a phenolic antioxidant (AO), Irganox 1010®, had been added, was investigated. To this end, a series of appropriate thermal analyzes methods (TGA, DSC, OIT measurements), were used for testing the polymer matrix oxidation level. We were able to correlate the diminution of AO concentration with the oxidation induction time and calculate the activation energy, thereby demonstrating the efficiency of the AO and the effect of radiation.

  6. Abundances of ethylene oxide and acetaldehyde in hot molecular cloud cores

    NASA Technical Reports Server (NTRS)

    Nummelin, A.; Dickens, J. E.; Bergman, P.; Hjalmarson, A.; Irvine, W. M.; Ikeda, M.; Ohishi, M.

    1998-01-01

    We have searched for millimetre-wave line emission from ethylene oxide (c-C2H4O) and its structural isomer acetaldehyde (CH3CHO) in 11 molecular clouds using SEST. Ethylene oxide and acetaldehyde were detected through multiple lines in the hot cores NGC 6334F, G327.3-0.6, G31.41+0.31, and G34.3+0.2. Acetaldehyde was also detected towards G10.47+0.03, G322.2+0.6, and Orion 3'N, and one ethylene oxide line was tentatively detected in G10.47+0.03. Column densities and rotational excitation temperatures were derived using a procedure which fits the observed line intensifies by finding the minimum chi 2-value. The resulting rotational excitation temperatures of ethylene oxide and acetaldehyde are in the range 16-38 K, indicating that these species are excited in the outer, cooler parts of the hot cores or that the excitation is significantly subthermal. For an assumed source size of 20", the deduced column densities are (0.6-1)x10(14) cm-2 for ethylene oxide and (2-5)x10(14) cm-2 for acetaldehyde. The fractional abundances with respect to H2 are X[c-C2H4O]=(2-6)xl0(-10), and X[CH3CHO]=(0.8-3)x10(-9). The ratio X[CH3CHO]/X[c-C2H4O] varies between 2.6 (NGC 6334F) and 8.5 (G327.3-0.6). We also detected and analysed multiple transitions of CH3OH, CH3OCH3, C2H5OH, and HCOOH. The chemical, and possibly evolutionary, states of NGC 6334F, G327.3-0.6, G31.41+0.31, and G34.3+0.2 seem to be very similar.

  7. Comprehensive Proteomics Analysis of Laticifer Latex Reveals New Insights into Ethylene Stimulation of Natural Rubber Production.

    PubMed

    Wang, Xuchu; Wang, Dan; Sun, Yong; Yang, Qian; Chang, Lili; Wang, Limin; Meng, Xueru; Huang, Qixing; Jin, Xiang; Tong, Zheng

    2015-01-01

    Ethylene is a stimulant to increase natural rubber latex. After ethylene application, both fresh yield and dry matter of latex are substantially improved. Moreover, we found that ethylene improves the generation of small rubber particles. However, most genes involved in rubber biosynthesis are inhibited by exogenous ethylene. Therefore, we conducted a proteomics analysis of ethylene-stimulated rubber latex, and identified 287 abundant proteins as well as 143 ethylene responsive latex proteins (ERLPs) with mass spectrometry from the 2-DE and DIGE gels, respectively. In addition, more than 1,600 proteins, including 404 ERLPs, were identified by iTRAQ. Functional classification of ERLPs revealed that enzymes involved in post-translational modification, carbohydrate metabolism, hydrolase activity, and kinase activity were overrepresented. Some enzymes for rubber particle aggregation were inhibited to prolong latex flow, and thus finally improved latex production. Phosphoproteomics analysis identified 59 differential phosphoproteins; notably, specific isoforms of rubber elongation factor and small rubber particle protein that were phosphorylated mainly at serine residues. This post-translational modification and isoform-specific phosphorylation might be important for ethylene-stimulated latex production. These results not only deepen our understanding of the rubber latex proteome but also provide new insights into the use of ethylene to stimulate rubber latex production. PMID:26348427

  8. Effect of Lithium on Thigmomorphogenesis in Bryonia dioica Ethylene Production and Sensitivity 1

    PubMed Central

    Boyer, Nicole; Desbiez, Marie-Odile; Hofinger, Michel; Gaspar, Thomas

    1983-01-01

    Rubbing internodes of Bryonia dioica plants reduced their ethylene production but increased their capacity to convert 1-aminocyclopropane-1-carboxylic acid (ACC) to ethylene. These results were explained by the previously shown rubbing-induced decrease of indoleacetic acid, which controls the level of ACC synthase, and by the increase of membrane-associated peroxidases which would participate in the conversion of ACC-ethylene. Pretreatment of the plants with Li had no significant effect on control plants but counteracted the rubbing-induced decrease of ethylene production and diminished the capacity of the internodes to convert ACC to ethylene. Exogenously applied ethylene induced an increase of peroxidase activity similar to that caused by rubbing. Inasmuch as both effects were reduced by Li, it was concluded that Li inhibition of thigmomorphogenetic processes was essentially due to a Li inhibition of the effect of ethylene formed in response to mechanical stimuli. The decreased ethylene production and ACC conversion capacity in the presence of Li were explained by a cellular redistribution of peroxidases. PMID:16663035

  9. Comprehensive Proteomics Analysis of Laticifer Latex Reveals New Insights into Ethylene Stimulation of Natural Rubber Production

    PubMed Central

    Wang, Xuchu; Wang, Dan; Sun, Yong; Yang, Qian; Chang, Lili; Wang, Limin; Meng, Xueru; Huang, Qixing; Jin, Xiang; Tong, Zheng

    2015-01-01

    Ethylene is a stimulant to increase natural rubber latex. After ethylene application, both fresh yield and dry matter of latex are substantially improved. Moreover, we found that ethylene improves the generation of small rubber particles. However, most genes involved in rubber biosynthesis are inhibited by exogenous ethylene. Therefore, we conducted a proteomics analysis of ethylene-stimulated rubber latex, and identified 287 abundant proteins as well as 143 ethylene responsive latex proteins (ERLPs) with mass spectrometry from the 2-DE and DIGE gels, respectively. In addition, more than 1,600 proteins, including 404 ERLPs, were identified by iTRAQ. Functional classification of ERLPs revealed that enzymes involved in post-translational modification, carbohydrate metabolism, hydrolase activity, and kinase activity were overrepresented. Some enzymes for rubber particle aggregation were inhibited to prolong latex flow, and thus finally improved latex production. Phosphoproteomics analysis identified 59 differential phosphoproteins; notably, specific isoforms of rubber elongation factor and small rubber particle protein that were phosphorylated mainly at serine residues. This post-translational modification and isoform-specific phosphorylation might be important for ethylene-stimulated latex production. These results not only deepen our understanding of the rubber latex proteome but also provide new insights into the use of ethylene to stimulate rubber latex production. PMID:26348427

  10. Janus-Type Dendrimer-like Poly(ethylene oxide)s

    PubMed Central

    Feng, Xiaoshuang; Taton, Daniel; Ibarboure, Emmanuel; Chaikof, Elliot L.; Gnanou, Yves

    2009-01-01

    A straightforward and original methodology allowing the synthesis of Janus-type dendrimer-like poly(ethylene oxide)s (PEOs) carrying orthogonal functional groups on their surface is described. The use of 3-allyloxy-1,2-propanediol (1) as a latent AB2-type heterofunctional initiator of anionic ring-opening polymerization (AROP) of ethylene oxide (EO) and of selective branching agents of PEO chain ends served to construct the two dendrons of these dendrimer-like PEOs, following a divergent pathway. Thus, the first PEO generation of the first dendron was grown by AROP from 1 followed by the reaction of the corresponding α-allyl,ω,ω′-bishydroxy- heterofunctional PEO derivative with 2-(3′-chloromethybenzyloxymethyl)-2-methyl-5,5-dimethyl-1,3-dioxane (2) used as a branching agent. This afforded the dendron A with four latent peripheral hydroxyls protected in the form of two ketal rings. The remaining α-allylic double bond of the PEO thus prepared was transformed into two hydroxyl groups using OsO4 in order to create the first PEO generation of the dendron B by AROP of EO. Allyl chloride (3) was then used as another (latent) branching agent to react with the terminal hydroxyl of the corresponding PEO chains. Deprotection under acidic conditions of the ketal groups of dendron A, followed by AROP of EO, afforded the second PEO generation on this face. This alternate and divergent procedure, combining AROP of EO and selective branching of PEO branches, could be readily iterated, one dendron after the other up to the generation six, leading to a Janus-type dendrimer-like PEO exhibiting a total mass of around 300 kg/mol and possessing 64 peripheral groups on each face. The possibility of orthogonal functionalization of the surfaces of such Janus-type dendritic PEOs was exploited. Indeed, a dendron of generation 4 was functionalized with hydroxyl functions at its periphery, whereas the other was end-capped with either tertiary amino or disulfide groups. In a variant of

  11. In-depth survey report: control technology for ethylene oxide sterilization at Euclid General Hospital, Euclid, Ohio

    SciTech Connect

    O'Brien, D.

    1985-06-01

    An indepth survey of control technology for ethylene oxide sterilization was conducted. Industrial hygiene sampling for ethylene-oxide was conducted. Engineering controls consisted of local exhaust ventilation above the sterilizers, at the drain, at the safety relief valve, and around the ethylene-oxide cylinders, general ventilation, and use of a pulse/purge phase at the end of the sterilization cycle. A three-component ethylene-oxide monitoring program was in place, consisting of continuous monitoring with an alarm system, environmental area monitoring performed by an outside contractor, and exposures were below 0.2 part per million. The OSHA time weighted average (TWA) standard for ethylene oxide is 1 ppm. Proper work practices for employees were outlined in a procedure and policy manual. The Central Services Director provided education and training on proper work practices and the hazards of ethylene-oxide exposure. The author concludes that the engineering controls at the facility successfully minimize employee exposure to ethylene oxide.

  12. Ethylene Oxide in Blood of Ethylene-Exposed B6C3F1 Mice, Fischer 344 Rats, and Humans

    PubMed Central

    Filser, Johannes Georg; Erbach, Eva; Faller, Thomas; Kreuzer, Paul Erich; Li, Qiang

    2013-01-01

    The gaseous olefin ethylene (ET) is metabolized in mammals to the carcinogenic epoxide ethylene oxide (EO). Although ET is the largest volume organic chemical worldwide, the EO burden in ET-exposed humans is still uncertain, and only limited data are available on the EO burden in ET-exposed rodents. Therefore, EO was quantified in blood of mice, rats, or 4 volunteers that were exposed once to constant atmospheric ET concentrations of between 1 and 10 000 ppm (rodents) or 5 and 50 ppm (humans). Both the compounds were determined by gas chromatography. At ET concentrations of between 1 and 10 000 ppm, areas under the concentration-time curves of EO in blood (µmol × h/l) ranged from 0.039 to 3.62 in mice and from 0.086 to 11.6 in rats. At ET concentrations ≤ 30 ppm, EO concentrations in blood were 8.7-fold higher in rats and 3.9-fold higher in mice than that in the volunteer with the highest EO burdens. Based on measured EO concentrations, levels of EO adducts to hemoglobin and lymphocyte DNA were calculated for diverse ET concentrations and compared with published adduct levels. For given ET exposure concentrations, there were good agreements between calculated and measured levels of adducts to hemoglobin in rats and humans and to DNA in rats and mice. Reported hemoglobin adduct levels in mice were higher than calculated ones. Furthermore, information is given on species-specific background adduct levels. In summary, the study provides most relevant data for an improved assessment of the human health risk from exposure to ET. PMID:24068676

  13. Ethylene oxide-block-butylene oxide copolymer uptake by silicone hydrogel contact lens materials

    NASA Astrophysics Data System (ADS)

    Huo, Yuchen; Ketelson, Howard; Perry, Scott S.

    2013-05-01

    Four major types of silicone hydrogel contact lens material have been investigated following treatments in aqueous solutions containing poly(ethylene oxide) and poly(butylenes oxide) block copolymer (EO-BO). The extent of lens surface modification by EO-BO and the degree of bulk uptake were studied using X-ray photoelectron spectroscopy (XPS) and ultra-performance liquid chromatography (UPLC), respectively. The experimental results suggest that different interaction models exist for the lenses, highlighting the influence of both surface and bulk composition, which greatly differs between the lenses examined. Specifically, lenses with hydrophilic surface treatments, i.e., PureVision® (balafilcon A) and O2OPTIX (lotrafilcon B), demonstrated strong evidence of preferential surface adsorption within the near-surface region. In comparison, surface adsorption on ACUVUE® Oasys® (senofilcon A) and Biofinity® (comfilcon A) was limited. As for bulk absorption, the amount of EO-BO uptake was the greatest for balafilcon A and comfilcon A, and least for lotrafilcon B. These findings confirm the presence of molecular concentration gradients within the silicone hydrogel lenses following exposure to EO-BO solutions, with the nature of such concentration gradients found to be lens-specific. Together, the results suggest opportunities for compositional modifications of lenses for improved performance via solution treatments containing surface-active agents.

  14. Calcium ion dependency of ethylene production in segments of primary roots of Zea mays

    NASA Technical Reports Server (NTRS)

    Hasenstein, K. H.; Evans, M. L.

    1986-01-01

    We investigated the effect of Ca2+ on ethylene production in 2-cm long apical segments from primary roots of corn (Zea mays L., B73 x Missouri 17) seedlings. The seedlings were raised under different conditions of Ca2+ availability. Low-Ca and high-Ca seedlings were raised by soaking the grains and watering the seedlings with distilled water or 10 mM CaCl2, respectively. Segments from high-Ca roots produced more than twice as much ethylene as segments from low-Ca roots. Indoleacetic acid (IAA; 1 micromole) enhanced ethylene production in segments from both low-Ca and high-Ca roots but auxin-induced promotion of ethylene production was consistently higher in segments from high-Ca roots. Addition of 1-aminocyclopropane-1-carboxylic acid (ACC) to root segments from low-Ca seedlings doubled total ethylene production and the rate of production remained fairly constant during a 24 h period of monitoring. In segments from high-Ca seedlings ACC also increased total ethylene production but most of the ethylene was produced within the first 6 h. The data suggest that Ca2+ enhances the conversion of ACC to ethylene. The terminal 2 mm of the root tip were found to be especially important to ethylene biosynthesis by apical segments and, experiments using 45Ca2+ as tracer indicated that the apical 2 mm of the root is the region of strongest Ca2+ accumulation. Other cations such as Mn2+, Mg2+, and K+ could largely substitute for Ca2+. The significance of these findings is discussed with respect to recent evidence for gravity-induced Ca2+ redistribution and its relationship to the establishment of asymmetric growth during gravitropic curvature.

  15. Molecular and structural characterization of hybrid poly(ethylene oxide)-polyhedral oligomeric silesquioxanes star-shaped macromolecules.

    PubMed

    Pozza, Gladys M-E; Crotty, Sarah; Rawiso, Michel; Schubert, Ulrich S; Lutz, Pierre J

    2015-01-29

    Octafunctionalized spherosilsesquioxanes (Q8M8(H)), decorated with Si-H functions, could be used to design, by coupling via hydrosilylation with α-methoxy-ω-undecenyl poly(ethylene oxide)s (PEOs), organic-inorganic nanocomposite structures. (1)H, (13)C, and (29)Si NMR; size exclusion chromatography; and Fourier transfrom infrared spectroscopy were used to follow the grafting reaction and determine the molar mass and the functionality of the different species. Hybrid star-shaped poly(ethylene oxide)s of precise molar mass and functionality could be isolated by fractional precipitation of the raw reaction product. Absolute molar masses of the purified star-shaped PEOs, calculated with the assumption of a functionality of 8, were comparable when measured by light scattering in methanol and by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Small-angle X-ray scattering was employed to determine their molecular and structural characteristics, representing the versatility and innovative aspect to this study. Both differential scanning calorimetry and optical microscopy were utilized to elaborate and analyze the thermal properties and crystallization, respectively, of the hybrid stars. Further ongoing work is being carried out currently to investigate and foresee the use of longer PEO branches onto the core. PMID:25531696

  16. Toxicology and carcinogenesis studies of ethylene oxide (CAS No. 75-21-8) in B6C3F1 mice (inhalation studies). Technical report series (Final). [Ethylene oxide

    SciTech Connect

    Not Available

    1987-11-01

    Two-year toxicology and carcinogenesis studies of ethylene oxide were conducted by exposing groups of 50 B6C3F(1) mice of each sex to air containing 0, 50, or 100 ppm ethylene oxide 6 hours per day, 5 days per week for 102 weeks. Under the conditions of these 2-year inhalation studies, there was clear evidence of carcinogenic activity for B6C3F(1) mice as indicated by dose-related increased incidences of benign or malignant neoplasms of the lung and benign neoplasms of the harderian gland in both male and female B6C3F(1) mice following exposure to ethylene oxide vapors at 50 and 100 ppm. In female mice, ethylene oxide caused additional malignant neoplasms of the uterus, mammary gland, and hematopoietic system (lymphoma).

  17. An Arabidopsis thaliana copper-sensitive mutant suggests a role of phytosulfokine in ethylene production

    PubMed Central

    Wu, Tao; Kamiya, Takehiro; Yumoto, Hiroko; Sotta, Naoyuki; Katsushi, Yamaguchi; Shigenobu, Shuji; Matsubayashi, Yoshikatsu; Fujiwara, Toru

    2015-01-01

    To increase our understanding of the adaptation for copper (Cu) deficiency, Arabidopsis mutants with apparent alterations under Cu deficiency were identified. In this report, a novel mutant, tpst-2, was found to be more sensitive than wild-type (Col-0) plants to Cu deficiency during root elongation. The positional cloning of tpst-2 revealed that this gene encodes a tyrosylprotein sulfotransferase (TPST). Moreover, the ethylene production of tpst-2 mutant was higher than that of Col-0 under Cu deficiency, and adding the ethylene response inhibitor AgNO3 partially rescued defects in root elongation. Interestingly, peptide hormone phytosulfokine (PSK) treatment also repressed the ethylene production of tpst-2 mutant plants. Our results revealed that TPST suppressed ethylene production through the action of PSK. PMID:25908239

  18. An Arabidopsis thaliana copper-sensitive mutant suggests a role of phytosulfokine in ethylene production.

    PubMed

    Wu, Tao; Kamiya, Takehiro; Yumoto, Hiroko; Sotta, Naoyuki; Katsushi, Yamaguchi; Shigenobu, Shuji; Matsubayashi, Yoshikatsu; Fujiwara, Toru

    2015-07-01

    To increase our understanding of the adaptation for copper (Cu) deficiency, Arabidopsis mutants with apparent alterations under Cu deficiency were identified. In this report, a novel mutant, tpst-2, was found to be more sensitive than wild-type (Col-0) plants to Cu deficiency during root elongation. The positional cloning of tpst-2 revealed that this gene encodes a tyrosylprotein sulfotransferase (TPST). Moreover, the ethylene production of tpst-2 mutant was higher than that of Col-0 under Cu deficiency, and adding the ethylene response inhibitor AgNO3 partially rescued defects in root elongation. Interestingly, peptide hormone phytosulfokine (PSK) treatment also repressed the ethylene production of tpst-2 mutant plants. Our results revealed that TPST suppressed ethylene production through the action of PSK. PMID:25908239

  19. Detection of interstellar ethylene oxide (c-C2H4O).

    PubMed

    Dickens, J E; Irvine, W M; Ohishi, M; Ikeda, M; Ishikawa, S; Nummelin, A; Hjalmarson, A

    1997-11-10

    We report the identification of 10 transitions that support the detection of the small cyclic molecule ethylene oxide (c-C2H4O) in Sgr B2N. Although one of these transitions is severely blended, so that an accurate intensity and line width could not be determined, and two other lines are only marginally detected, we have done Gaussian fits to the remaining seven lines and have performed a rotation diagram analysis. Our results indicate a rotation temperature T(rot) = 18 K and a molecular column density N(c-C2H4O) = 3.3 x 10(14) cm-2, corresponding to a fractional abundance relative to molecular hydrogen of order 6 x 10(-11). This is a factor of more than 200 higher than the abundance for this molecule suggested by the "new standard" chemistry model of Lee, Bettens, & Herbst. This result suggests that grain chemistry might play an effective role in the production of c-C2H4O. No transitions of this molecule were detected in either Sgr B2M or Sgr B2NW. PMID:11541726

  20. Polycation-sodium lauryl ether sulfate-type surfactant complexes: influence of ethylene oxide length.

    PubMed

    Vleugels, Leo F W; Pollet, Jennifer; Tuinier, Remco

    2015-05-21

    Polyelectrolyte-surfactant complexes (PESC) are a class of materials which form spontaneously by self-assembly driven by electrostatic and hydrophobic interactions. PESC containing sodium lauryl ether sulfates (SLES) have found wide application in hair care products like shampoo. Typically, SLES with only one or two ethylene oxide (EO) groups are used for this application. We have studied the influence of the size of the EO block (ranging from 0 to 30 EO groups) on complexation with two model polycations: linear polyDADMAC and branched PEI. PESC size and electrostatic properties were determined during stepwise titration of buffered polycation solutions. The critical aggregation concentration (CAC) of PESC was determined by surface tension measurements and fluorescence spectroscopy. For polyDADMAC, there is no influence of the size of the EO block on the complexation behavior; the stiff polycation governs the structure formation. For PEI, it was seen that the EO block size does affect the structure of the complexes. The CAC value of the investigated complexes turns out to be rather independent of the EO block size; however, the CMC/CAC ratio decreases with increasing size of the EO block. This latter observation explains why the Lochhead-Goddard effect is most effective for small EO blocks. PMID:25940957

  1. Detection of Interstellar Ethylene Oxide (c-C2H4O)

    NASA Astrophysics Data System (ADS)

    Dickens, J. E.; Irvine, W. M.; Ohishi, M.; Ikeda, M.; Ishikawa, S.; Nummelin, A.; Hjalmarson, A.

    1997-01-01

    We report the identification of 10 transitions which support the detection of the small cyclic molecule ethylene oxide (c-C2H40) in SgrB2(N). Although one of these transitions is severely blended, such that an accurate intensity and linewidth could not be determined, and two other lines are only marginally detected, we have done gaussian fits to the remaining 7 lines and have performed a rotation diagram analysis. Our results indicate a rotation temperature, Trot = 18 K, and a molecular column density, N(c-C2H40) = 3.3 x 1014cm-2, corresponding to a fractional abundance relative to molecular hydrogen of order 6 x 10exp -11). This is a factor of more than 200 higher than the abundance for this molecule suggested by the "new standard" chemistry model of Lee, Bettens, & Herbst (1996). This result suggests that grain chemistry might play an effective role in the production Of c-C2H40. No transitions of this molecule were detected in either SgrB2(M) or SgrB2(NW).

  2. Detection of Interstellar Ethylene Oxide (c-C2H4O)

    NASA Astrophysics Data System (ADS)

    Dickens, J. E.; Irvine, W. M.; Ohishi, M.; Ikeda, M.; Ishikawa, S.; Nummelin, A.; Hjalmarson, Å.

    1997-11-01

    We report the identification of 10 transitions that support the detection of the small cyclic molecule ethylene oxide (c-C2H4O) in Sgr B2N. Although one of these transitions is severely blended, so that an accurate intensity and line width could not be determined, and two other lines are only marginally detected, we have done Gaussian fits to the remaining seven lines and have performed a rotation diagram analysis. Our results indicate a rotation temperature Trot = 18 K and a molecular column density N(c-C2H4O) = 3.3 × 1014 cm-2, corresponding to a fractional abundance relative to molecular hydrogen of order 6 × 10-11. This is a factor of more than 200 higher than the abundance for this molecule suggested by the ``new standard'' chemistry model of Lee, Bettens, & Herbst. This result suggests that grain chemistry might play an effective role in the production of c-C2H4O. No transitions of this molecule were detected in either Sgr B2M or Sgr B2NW.

  3. Health Hazard Evaluation Report HETA 85-065-1578, United Hospital, Grand Forks, North Dakota. [Ethylene oxide

    SciTech Connect

    Gunter, B.J.

    1985-04-01

    Environmental and breathing zone samples were analyzed for ethylene-oxide at United Hospital, Grand Forks, North Dakota in January, 1985. The survey was requested by the management to determine if using ethylene-oxide for sterilization purposes posed a health risk. All employees (number not specified) in the central supply department were interviewed. These concentrations originated from an old sterilizer. The sterilizer was not normally used, but was operated on the day of the survey to stimulate a worst-case situation. None of the workers had any medical complaints. The author concludes that a health hazard due to ethylene-oxide does not exist at the facility. He recommends not using the old sterilizer until it has been refurbished and conducting periodic monitoring for ethylene/oxide with an infrared analyzer.

  4. Study of the desorption of ethylene oxide fixed on various materials during sterilization by a new procedure

    NASA Technical Reports Server (NTRS)

    Lacomme, M.; Chaigneau, M.; Lemoan, G.

    1977-01-01

    A continuous sterilization process using ethylene oxide was studied in comparison with a classical method in order to evaluate gas retention as a function of time and temperature on polyethylene, PVC, and rubber materials.

  5. Nano-structured Platinum-based Catalysts for the Complete Oxidation of Ethylene Glycol and Glycerol

    NASA Astrophysics Data System (ADS)

    Falase, Akinbayowa

    Direct alcohol fuel cells are a viable alternative to the traditional hydrogen PEM fuel cell. Fuel versatility, integration with existing distribution networks, and increased safety when handling these fuels increases their appeal for portable power applications. In order to maximize their utility, the liquid fuel must be fully oxidized to CO2 so as to harvest the full amount of energy. Methanol and ethanol are widely researched as potential fuels to power these devices, but methanol is a toxic substance, and ethanol has a much lower energy density than other liquids such as gasoline or glucose. Oxidation of complex fuels is difficult to realize, due to difficulty in breaking carbon-carbon bonding and poisoning of the catalysts by oxidative byproducts. In order to achieve the highest efficiency, an anode needs to be engineered in such a way as to maximize activity while minimizing poisoning effects of reaction byproducts. We have engineered an anode that uses platinum-based catalysts that is capable of completely oxidizing ethylene glycol and glycerol in neutral and alkaline media with little evidence of CO poisoning. We have constructed a hybrid anode consisting of a nano-structured PtRu electrocatayst with an NAD-dependent alcohol dehydrogenase for improved oxidation of complex molecules. A nano-structured PtRu catalyst was used to oxidize ethylene glycol and glycerol in neutral media. In situ infrared spectroscopy was used to verify complete oxidation via CO2 generation. There was no evidence of poisoning by CO species. A pH study was performed to determine the effect of pH on oxidative current. The peak currents did not trend at 60 mV/pH unit as would be expected from the Nernst equation, suggesting that adsorption of fuel to the surface of the electrode is not an electron-transfer step. We synthesized nano-structured PtRu, PtSn, and PtRuSn catalysts for oxidation of ethylene glycol and glycerol in alkaline media. The PtRu electrocatalyst the highest oxidative

  6. Linear poly(ethylene oxide)-based polyurethane hydrogels: polyurethane-ureas and polyurethane-amides.

    PubMed

    Petrini, P; Tanzi, M C; Moran, C R; Graham, N B

    1999-01-01

    Over the last 30 years, water-swellable and water-insoluble hydrogels have been extensively investigated and developed, leading to a large family of materials which have found uses in a wide range of biomedical applications. While hydrogels usually present a crosslinked structure, linear polyurethane-ureas (PUUs) based on poly(ethylene oxide) have been shown to be able to absorb and swell with aqueous media without dissolving. This behavior is due to the phase separated domain morphology, where hydrogen bonded urethane/urea hard segment domains are dispersed in a PEO soft segment domain. This work investigates the possibility of obtaining linear poly(ethylene oxide)-based polyurethane-amide (PUA) hydrogels using two amide diols as chain extenders, a mono amide diol (AD) and a diamide diol (DD), and a dicarboxylic acid (maleic acid, MA). Poly(ethylene oxide) based PUAs were obtained using a "one-shot" bulk polymerization technique. The chemicophysical characterization and water-solubility tests showed that these materials, while having molecular weights similar to the PUUs, do not possess sufficient phase separation, hydrogen bonding and hydrophobicity of the hard segment domains to exhibit hydrogel behavior. Crosslinked PUAs using maleic acid as chain extender show interesting hydrogel properties. PMID:15347978

  7. Nitric Oxide, Ethylene, and Auxin Cross Talk Mediates Greening and Plastid Development in Deetiolating Tomato Seedlings1[OPEN

    PubMed Central

    Melo, Nielda K.G.; Bianchetti, Ricardo E.; Oliveira, Paulo M.R.; Demarco, Diego

    2016-01-01

    The transition from etiolated to green seedlings involves the conversion of etioplasts into mature chloroplasts via a multifaceted, light-driven process comprising multiple, tightly coordinated signaling networks. Here, we demonstrate that light-induced greening and chloroplast differentiation in tomato (Solanum lycopersicum) seedlings are mediated by an intricate cross talk among phytochromes, nitric oxide (NO), ethylene, and auxins. Genetic and pharmacological evidence indicated that either endogenously produced or exogenously applied NO promotes seedling greening by repressing ethylene biosynthesis and inducing auxin accumulation in tomato cotyledons. Analysis performed in hormonal tomato mutants also demonstrated that NO production itself is negatively and positively regulated by ethylene and auxins, respectively. Representing a major biosynthetic source of NO in tomato cotyledons, nitrate reductase was shown to be under strict control of both phytochrome and hormonal signals. A close NO-phytochrome interaction was revealed by the almost complete recovery of the etiolated phenotype of red light-grown seedlings of the tomato phytochrome-deficient aurea mutant upon NO fumigation. In this mutant, NO supplementation induced cotyledon greening, chloroplast differentiation, and hormonal and gene expression alterations similar to those detected in light-exposed wild-type seedlings. NO negatively impacted the transcript accumulation of genes encoding phytochromes, photomorphogenesis-repressor factors, and plastid division proteins, revealing that this free radical can mimic transcriptional changes typically triggered by phytochrome-dependent light perception. Therefore, our data indicate that negative and positive regulatory feedback loops orchestrate ethylene-NO and auxin-NO interactions, respectively, during the conversion of colorless etiolated seedlings into green, photosynthetically competent young plants. PMID:26829981

  8. Iron oxide/cassava starch-supported Ziegler-Natta catalysts for in situ ethylene polymerization.

    PubMed

    Chancharoenrith, Sittikorn; Kamonsatikul, Choavarit; Namkajorn, Montree; Kiatisevi, Supavadee; Somsook, Ekasith

    2015-03-01

    Iron oxide nanoparticles were used as supporters for in situ polymerization to produce polymer nanocomposites with well-dispersed fillers in polymer matrix. Iron oxide could be sustained as colloidal solutions by cassava starch to produce a good dispersion of iron oxide in the matrix. New supports based on iron oxide/cassava starch or cassava starch for Ziegler-Natta catalysts were utilized as heterogeneous supporters for partially hydrolyzed triethylaluminum. Then, TiCl4 was immobilized on the supports as catalysts for polymerization of ethylene. High-density polyethylene (HDPE) composites were obtained by the synthesized catalysts. A good dispersion of iron oxide/cassava starch particles was observed in the synthesized polymer matrix promoting to good mechanical properties of HDPE. PMID:25498641

  9. Process for the production of ethylene and other hydrocarbons from coal

    DOEpatents

    Steinberg, Meyer; Fallon, Peter

    1986-01-01

    A process for the production of economically significant amounts of ethyl and other hydrocarbon compounds, such as benzene, from coal is disclosed wherein coal is reacted with methane at a temperature in the approximate range of 500.degree. C. to 1100.degree. C. at a partial pressure less than about 200 psig for a period of less than 10 seconds. Ethylene and other hydrocarbon compounds may be separated from the product stream so produced, and the methane recycled for further production of ethylene. In another embodiment, other compounds produced, such as by-product tars, may be burned to heat the recycled methane.

  10. Metabolic engineering of Corynebacterium glutamicum for the de novo production of ethylene glycol from glucose.

    PubMed

    Chen, Zhen; Huang, Jinhai; Wu, Yao; Liu, Dehua

    2016-01-01

    Development of sustainable biological process for the production of bulk chemicals from renewable feedstock is an important goal of white biotechnology. Ethylene glycol (EG) is a large-volume commodity chemical with an annual production of over 20 million tons, and it is currently produced exclusively by petrochemical route. Herein, we report a novel biosynthetic route to produce EG from glucose by the extension of serine synthesis pathway of Corynebacterium glutamicum. The EG synthesis is achieved by the reduction of glycoaldehyde derived from serine. The transformation of serine to glycoaldehyde is catalyzed either by the sequential enzymatic deamination and decarboxylation or by the enzymatic decarboxylation and oxidation. We screened the corresponding enzymes and optimized the production strain by combinatorial optimization and metabolic engineering. The best engineered C. glutamicum strain is able to accumulate 3.5 g/L of EG with the yield of 0.25 mol/mol glucose in batch cultivation. This study lays the basis for developing an efficient biological process for EG production. PMID:26556130

  11. Monitoring human exposure to ethylene oxide by the determination of hemoglobin adducts using gas chromatography-mass spectrometry

    SciTech Connect

    Farmer, P.B.; Bailey, E.; Gorf, S.M.; Toernqvist, M.O.; Osterman-Golkar, S.; Kautiainen, A.; Lewis-Enright, D.P.

    1986-04-01

    Globin samples from ethylene oxide-exposed workers and non-exposed referrents were analyzed by two methods: (i) gas chromatography-mass spectrometry determination of Nt-(2-hydroxyethyl)histidine as its methyl ester heptafluorobutyryl derivative, after hydrolysis of the protein and isolation of the alkylated amino acid by ion exchange chromatography. The internal standard, Nt-(2-hydroxy-d4-ethyl)histidine, was added to the protein before hydrolysis. (ii) Determination of N-(2-hydroxyethyl)valine after derivatization of the protein by a modified Edman procedure, extraction and g.c.-m.s. determination of alkylated N-terminal valine in the form of its pentafluorophenylthiohydantoin derivative. The internal standard used was in this case a globin with a known content of hydroxy-d4-ethylated amino acids. The two methods gave consistent results, especially at high levels of alkylated products. The average content of hydroxyethylhistidine was 0.6 nmol/g higher than the content of hydroxyethylvaline. Higher levels of background alkylation (of unknown origin) were recorded with the histidine method as compared with the valine method, suggesting that the latter assay should show greater sensitivity for low level ethylene oxide exposure monitoring.

  12. Process for the production of ethylene and other hydrocarbons from coal

    SciTech Connect

    Steinberg, M.; Fallon, P.

    1982-02-16

    A process is claimed for the production of substantial amounts of ethylene and other hydrocarbon compounds, such as benzene from coal. Coal is reacted with methane at a temperature in the approximate range of 500/sup 0/C to 1100/sup 0/C at a partial pressure less than about 200 psig for a period of less than 10 seconds, and preferably at a temperature of approximately 850/sup 0/C, and a partial pressure of 50 psig for a period of approximately 2 seconds. Ethylene and other hydrocarbon compounds may be separated from the product stream so produced, and the methane recycled for further production of ethylene. In another embodiment, other compounds produced, such as by-product tars, may be burned to heat the recycled methane.

  13. Mechanical Characterization of Hybrid Vesicles Based on Linear Poly(Dimethylsiloxane-b-Ethylene Oxide) and Poly(Butadiene-b-Ethylene Oxide) Block Copolymers.

    PubMed

    Gaspard, Jeffery; Casey, Liam M; Rozin, Matt; Munoz-Pinto, Dany J; Silas, James A; Hahn, Mariah S

    2016-01-01

    Poly(dimethylsiloxane-ethylene oxide) (PDMS-PEO) and poly(butadiene-b-ethylene oxide) (PBd-PEO) are two block copolymers which separately form vesicles with disparate membrane permeabilities and fluidities. Thus, hybrid vesicles formed from both PDMS-PEO and PBd-PEO may ultimately allow for systematic, application-specific tuning of vesicle membrane fluidity and permeability. However, given the relatively low strength previously noted for comb-type PDMS-PEO vesicles, the mechanical robustness of the resulting hybrid vesicles must first be confirmed. Toward this end, we have characterized the mechanical behavior of vesicles formed from mixtures of linear PDMS-PEO and linear PBd-PEO using micropipette aspiration. Tension versus strain plots of pure PDMS12-PEO46 vesicles revealed a non-linear response in the high tension regime, in contrast to the approximately linear response of pure PBd33-PEO20 vesicles. Remarkably, the area expansion modulus, critical tension, and cohesive energy density of PDMS12-PEO46 vesicles were each significantly greater than for PBd33-PEO20 vesicles, although critical strain was not significantly different between these vesicle types. PDMS12-PEO46/PBd33-PEO20 hybrid vesicles generally displayed graded responses in between that of the pure component vesicles. Thus, the PDMS12-PEO46/PBd33-PEO20 hybrid vesicles retained or exceeded the strength and toughness characteristic of pure PBd-PEO vesicles, indicating that future assessment of the membrane permeability and fluidity of these hybrid vesicles may be warranted. PMID:26999148

  14. Mechanical Characterization of Hybrid Vesicles Based on Linear Poly(Dimethylsiloxane-b-Ethylene Oxide) and Poly(Butadiene-b-Ethylene Oxide) Block Copolymers

    PubMed Central

    Gaspard, Jeffery; Casey, Liam M.; Rozin, Matt; Munoz-Pinto, Dany J.; Silas, James A.; Hahn, Mariah S.

    2016-01-01

    Poly(dimethylsiloxane-ethylene oxide) (PDMS-PEO) and poly(butadiene-b-ethylene oxide) (PBd-PEO) are two block copolymers which separately form vesicles with disparate membrane permeabilities and fluidities. Thus, hybrid vesicles formed from both PDMS-PEO and PBd-PEO may ultimately allow for systematic, application-specific tuning of vesicle membrane fluidity and permeability. However, given the relatively low strength previously noted for comb-type PDMS-PEO vesicles, the mechanical robustness of the resulting hybrid vesicles must first be confirmed. Toward this end, we have characterized the mechanical behavior of vesicles formed from mixtures of linear PDMS-PEO and linear PBd-PEO using micropipette aspiration. Tension versus strain plots of pure PDMS12-PEO46 vesicles revealed a non-linear response in the high tension regime, in contrast to the approximately linear response of pure PBd33-PEO20 vesicles. Remarkably, the area expansion modulus, critical tension, and cohesive energy density of PDMS12-PEO46 vesicles were each significantly greater than for PBd33-PEO20 vesicles, although critical strain was not significantly different between these vesicle types. PDMS12-PEO46/PBd33-PEO20 hybrid vesicles generally displayed graded responses in between that of the pure component vesicles. Thus, the PDMS12-PEO46/PBd33-PEO20 hybrid vesicles retained or exceeded the strength and toughness characteristic of pure PBd-PEO vesicles, indicating that future assessment of the membrane permeability and fluidity of these hybrid vesicles may be warranted. PMID:26999148

  15. Overcoming substrate limitations for improved production of ethylene in E. coli

    DOE PAGESBeta

    Lynch, Sean; Eckert, Carrie; Yu, Jianping; Gill, Ryan; Maness, Pin -Ching

    2016-01-04

    Ethylene is an important industrial compound for the production of a wide variety of plastics and chemicals. At present, ethylene production involves steam cracking of a fossil-based feedstock, representing the highest CO2-emitting process in the chemical industry. Biological ethylene production can be achieved via expression of a single protein, the ethylene-forming enzyme (EFE), found in some bacteria and fungi; it has the potential to provide a sustainable alternative to steam cracking, provided that significant increases in productivity can be achieved. A key barrier is determining factors that influence the availability of substrates for the EFE reaction in potential microbial hosts.more » In the presence of O2, EFE catalyzes ethylene formation from the substrates α-ketoglutarate (AKG) and arginine. The concentrations of AKG, a key TCA cycle intermediate, and arginine are tightly controlled by an intricate regulatory system that coordinates carbon and nitrogen metabolism. Thus, reliably predicting which genetic changes will ultimately lead to increased AKG and arginine availability is challenging.« less

  16. Organic chemistry. A rhodium catalyst for single-step styrene production from benzene and ethylene.

    PubMed

    Vaughan, Benjamin A; Webster-Gardiner, Michael S; Cundari, Thomas R; Gunnoe, T Brent

    2015-04-24

    Rising global demand for fossil resources has prompted a renewed interest in catalyst technologies that increase the efficiency of conversion of hydrocarbons from petroleum and natural gas to higher-value materials. Styrene is currently produced from benzene and ethylene through the intermediacy of ethylbenzene, which must be dehydrogenated in a separate step. The direct oxidative conversion of benzene and ethylene to styrene could provide a more efficient route, but achieving high selectivity and yield for this reaction has been challenging. Here, we report that the Rh catalyst ((Fl)DAB)Rh(TFA)(η(2)-C2H4) [(Fl)DAB is N,N'-bis(pentafluorophenyl)-2,3-dimethyl-1,4-diaza-1,3-butadiene; TFA is trifluoroacetate] converts benzene, ethylene, and Cu(II) acetate to styrene, Cu(I) acetate, and acetic acid with 100% selectivity and yields ≥95%. Turnover numbers >800 have been demonstrated, with catalyst stability up to 96 hours. PMID:25908817

  17. Self-Organization and Vesicle Formation of Amphiphilic Fulleromonodendrons Bearing Oligo(poly(ethylene oxide)) Chains.

    PubMed

    Chen, Mengjun; Zhu, Hongxia; Zhou, Shengju; Xu, Wenlong; Dong, Shuli; Li, Hongguang; Hao, Jingcheng

    2016-03-15

    A new series of N-methylfulleropyrrolidines bearing oligo(poly(ethylene oxide))-appended Percec monodendrons (fulleromonodendrons, 4a-f) have been synthesized. The substituted position of the oligo(poly(ethylene oxide)) chain(s) on the phenyl group of the Percec monodendron for 4a-f was varied, which is at the 4-, 2,4-, 3,5-, 3,4,5-, 2,3,4- and 2,4,6- position, respectively. 4a-e are obtained as solids at 25 °C and can self-organize into lamellar phases as revealed by X-ray diffraction (XRD) and small-angle X-ray scattering (SAXS) measurements, while 4f appears as a viscous liquid. The substitution patterns of the oligo(poly(ethylene oxide)) chain(s) also significantly influence the solubility of 4a-f, especially in ethanol and water. Formation of self-organized supramolecular structures of 4d and 4e in water as well as 4d in ethanol is evidenced from UV-vis and dynamic light scattering (DLS) measurements. Further studies in water using various imaging techniques including transmission electron microscopy (TEM), freeze-fracture TEM (FF-TEM), cryo-TEM and atomic force microscopy (AFM) observations revealed the formation of well-defined vesicles for 4d and plate-like aggregates for 4e, indicating that the aggregation behavior of the fulleromonodendrons is highly dependent on their molecular structures. For 4d in ethanol, only irregular aggregates were noticed, indicating the solvent also plays a role on regulating the aggregation behavior. After functionalization with the Percec monodendrons, 4a-f can preserve the intriguing electrochemical properties of pristine C60 as revealed by cyclic voltammetries. The thermotropic properties of 4a-f have also been investigated. It was found that all of them show good thermal stability, but no mesophases were detected within the investigated temperature ranges. PMID:26898216

  18. [The effect of physiologically active compounds on the production of ethylene and the activity of polygalacturonase inhibiting protein in fruits].

    PubMed

    Bulantseva, E A; Protsenko, M A; Toropkina, A S; Korableva, N P

    2011-01-01

    The treatment of apple and banana fruits with 2-CEFA and ethacyde induced the production of ethylene and accelerated the ripening and accumulation of ACC in apple fruits. Inhibitors AOA, AVG, and CoCl2 acted at the different steps of ethylene biosynthesis, inhibited the physiological aging process and increased storage longevity. Treatment with astaxantine and BOA delayed the pick of ethylene production by fruits. The content of PGIP was correlated with intensity of ethylene production. The infection of fruits with phytopathogenic microorganisms lowered as the result of the inhibition of pathogen PG. The dynamics of PGIP activity in fruits suggests its important role in the processes of ripening. PMID:22808745

  19. Comparison of methanol and ethylene glycol oxidation by alloy and Core-Shell platinum based catalysts

    NASA Astrophysics Data System (ADS)

    Kaplan, D.; Burstein, L.; Rosenberg, Yu.; Peled, E.

    2011-10-01

    Two Core-Shell, RuCore-PtShell and IrNiCore-PtRuShell, XC72-supported catalyst were synthesized in a two-step deposition process with NaBH4 as reducing agent. The structure and composition of the Core-Shell catalysts were determined by EDS, XPS and XRD. Electrochemical characterization was performed with the use of cyclic voltammetry. Methanol and ethylene glycol oxidation activities of the Core-Shell catalysts (in terms of surface and mass activities) were studied at 80 °C and compared to those of a commercial Pt-Ru alloy catalyst. The surface activity of the alloy based catalyst, in the case of methanol oxidation, was found to be superior as a result of optimized surface Pt:Ru composition. However, the mass activity of the PtRu/IrNi/XC72 was higher than that of the alloy based catalyst by ∼50%. Regarding ethylene glycol oxidation, while the surface activity of the alloy based catalyst was slightly higher than that of the Pt/Ru/XC72 catalyst, the latter showed ∼66% higher activities in terms of A g-1 of Pt. These results show the potential of Core-Shell catalysts for reducing the cost of catalysts for DMFC and DEGFC.

  20. Poly(isophthalic acid)(ethylene oxide) as a Macromolecular Modulator for Metal-Organic Polyhedra.

    PubMed

    Chen, Teng-Hao; Wang, Le; Trueblood, Jonathan V; Grassian, Vicki H; Cohen, Seth M

    2016-08-01

    A new strategy was developed by using a polymer ligand, poly(isophthalic acid)(ethylene oxide), to modulate the growth of metal-organic polyhedra (MOP) crystals. This macromolecular modulator can effectively control the crystal habit of several different Cu24L24 (L = isophthalic acid derivatives) MOPs. The polymer also directed the formation of MOP structures under reaction conditions that only produce metal-organic frameworks in the absence of modulator. Moreover, the polymer also enabled the deposition of MOP crystals on glass surfaces. This macromolecular modulator strategy provides an innovative approach to control the morphology and assembly of MOP particles. PMID:27400759

  1. Synthesis and Properties of Highly Dispersed Ionic Silica–Poly(ethylene oxide) Nanohybrids

    PubMed Central

    2013-01-01

    We report an ionic hybrid based on silica nanoparticles as the anion and amine-terminated poly(ethylene oxide) (PEO) as a cation. The charge on the nanoparticle anion is carried by the surface hydroxyls. SAXS and TEM reveal an exceptional degree of dispersion of the silica in the polymer and high degree of order in both thin film and bulk forms. In addition to better dispersion, the ionic hybrid shows improved flow characteristics compared to silica/PEO mixtures in which the ionic interactions are absent. PMID:23351113

  2. Extrusion of polysaccharide nanocrystal reinforced polymer nanocomposites through compatibilization with poly(ethylene oxide).

    PubMed

    Pereda, Mariana; El Kissi, Nadia; Dufresne, Alain

    2014-06-25

    Polysaccharide nanocrystals with a rodlike shape but with different dimensions and specific surface area were prepared from cotton and capim dourado cellulose, and with a plateletlike morphology from waxy maize starch granules. The rheological behavior of aqueous solutions of poly(ethylene oxide) (PEO) with different molecular weights when adding these nanoparticles was investigated evidencing specific interactions between PEO chains and nanocrystals. Because PEO also bears hydrophobic moieties, it was employed as a compatibilizing agent for the melt processing of polymer nanocomposites. The freeze-dried mixtures were used to prepare nanocomposite materials with a low density polyethylene matrix by extrusion. The thermal and mechanical behavior of ensuing nanocomposites was studied. PMID:24840363

  3. Morphological, rheological and electrochemical studies ofpoly(ethylene oxide) electrolytes containing fumed silicananoparticles

    SciTech Connect

    Xie, Jiangbing; Kerr, John B.; Duan, Robert G.; Han, Yongbong

    2003-06-01

    In this paper, the rheology and crystallization of composite Poly(Ethylene Oxide) (PEO) electrolytes were studied by dynamic mechanical analysis, DSC and polarized light microscopy. The effects of fumed silica nanoparticles on the conductivities of the polymer electrolytes at temperatures above and below their melting point were measured and related to their rheology and crystallization behavior, respectively. The electrolyte/electrode interfacial properties and cycling performances of the composite polymer electrolytes in Li/Li cells are also discussed. The measured electrochemical properties were found to depend heavily on the operational environments and sample processing history.

  4. Mutagenicity and cytotoxicity of ethylene oxide in the CHO/HGPRT system

    SciTech Connect

    Tan, E.L.; Cumming, R.B.; Hsie, A.W.

    1981-01-01

    Ethylene oxide (EO) is made on an industrial scale (2.5 billion pounds per year) and is used not only to prepare a number of commercially important compounds but also as a widely used fumigant to sterilize foodstuffs, textiles, and medical instruments. EO is an alkylating agent that has been shown to interact with proteins and nucleic acids and is mutagenic in a number of test systems, eg, rodents, bacteria, rice, and Drosophila. Reported is the cytotoxicity and mutagenicity of EO in a mammalian cel culture system, the Chinese hamster ovary cell/hypoxanthine-guanine phosphoribosyl transferase (CHO/HGPRT) system.

  5. Viscosity of copper oxide nanoparticles dispersed in ethylene glycol and water mixture

    SciTech Connect

    Namburu, Praveen K.; Kulkarni, Devdatta P.; Das, Debendra K.; Misra, Debasmita

    2007-11-15

    Nanofluids are new kinds of fluids engineered by dispersing nanoparticles in base fluids. This paper presents an experimental investigation of rheological properties of copper oxide nanoparticles suspended in 60:40 (by weight) ethylene glycol and water mixture. Nanofluids of particle volume percentage ranging from 0% to 6.12% were tested. The experiments were carried over temperatures ranging from -35 C to 50 C to demonstrate their applicability in cold regions. For the particle volume concentrations tested, nanofluids exhibited Newtonian behavior. An experimental correlation was developed based on the data, which relates viscosity with particle volume percent and the nanofluid temperature. (author)

  6. Formation of Copper Catalysts for CO2 Reduction with High Ethylene/Methane Product Ratio Investigated with In Situ X-ray Absorption Spectroscopy.

    PubMed

    Eilert, André; Roberts, F Sloan; Friebel, Daniel; Nilsson, Anders

    2016-04-21

    Nanostructured copper cathodes are among the most efficient and selective catalysts to date for making multicarbon products from the electrochemical carbon dioxide reduction reaction (CO2RR). We report an in situ X-ray absorption spectroscopy investigation of the formation of a copper nanocube CO2RR catalyst with high activity that highly favors ethylene over methane production. The results show that the precursor for the copper nanocube formation is copper(I)-oxide, not copper(I)-chloride as previously assumed. A second route to an electrochemically similar material via a copper(II)-carbonate/hydroxide is also reported. This study highlights the importance of using oxidized copper precursors for constructing selective CO2 reduction catalysts and shows the precursor oxidation state does not affect the electrocatalyst selectivity toward ethylene formation. PMID:27045045

  7. [Discussion about the sampling positions of the bag-type infusion sets for single use in the ethylene oxide residues detection].

    PubMed

    Liu, Xing; Zheng, Dixin; Geng, Yuanyuan; Chen, Zheng

    2014-01-01

    This paper selects the bag-type infusion sets for single use as samples, which are produced by different manufacturers and based on the ethylene oxide sterilization. The ethylene oxide sterilization residues in different parts of samples are detected by colorimetric analysis. Combined the comparison of the ethylene oxide residues testing results in the different parts of the same sample with the actual situation in clinical use, more reasonable sampling positions are found to detect the ethylene oxide sterilization residues. The result of this experiment will play a guiding role in the detection of the actual samples. PMID:24839856

  8. Thigmomorphogenesis: the relationship of mechanical perturbation to elicitor-like activity and ethylene production

    NASA Technical Reports Server (NTRS)

    Takahashi, H.; Jaffe, M. J.

    1984-01-01

    An extracellular solution obtained from bean (Phaseolus vulgaris L. cv. Resistant Cherokee Wax) stems induced phytoalexin-like substance and ethylene production in a soybean [Glycine max (L.) Merr. cv. Wayne] cotyledon bioassay. The elicitor-like activity for phytoalexin formation and ethylene production was increased by mechanical perturbation of bean stems. Moreover, the application of extracted or known elicitors to bean plants mimicked the effect of mechanical perturbation (i.e., inhibition of stem elongation and enhancement of radial growth). The effects of extract when applied exogenously, on elicitor-like activity in the bioassay as well as stem thickening were decreased by aminoethoxyvinylglycine, an inhibitor of ethylene biosynthesis. These results suggest that elicitor-like substances which are formed in response to mechanical perturbation contribute to the thigmomorphogenesis.

  9. Health-hazard evaluation report HETA 85-292-1811, Clark County Hospital, Jeffersonville, Indiana. [Ethylene oxide

    SciTech Connect

    Zey, J.N.; Elliott, L.; Mortimer, V.

    1987-07-01

    A request was received from Clark County Hospital located in Jeffersonville, Indiana to evaluate possible employee exposures to hazardous substances while working in the central-supply (CS) area. Symptoms expressed by workers included headaches, dizziness, mucous membrane irritation, vomiting, diarrhea, nose bleeds, fatigue, nervous problems, and respiratory difficulties. Workers had reported smelling a sweet odor at times. Air sampling yielded time-weighted average personal-exposure concentrations of 0.23 to 0.56 parts per million (ppm) for ethylene oxide with short-term exposures of 77 ppm in the cart-storage area. The OSHA standard was 1 ppm, and the NIOSH recommended criterion was 0.1 ppm of ethylene oxide. Hydrochloric acid concentrations in area air samples were less than 1.0 ppm; for chlorine gas, less than 0.2 ppm; for carbon monoxide, less than 5.0 ppm; and up to 700 ppm for carbon dioxide. The lack of a dedicated ethylene oxide exhaust and the existence of an overloaded exhaust system were noted. The authors conclude that a health hazard to workers from exposure to ethylene oxide existed. They recommend specific measures to reduce exposures to ethylene oxide, including design and installation of a proper ventilation system.

  10. Cadmium-induced ethylene production and responses in Arabidopsis thaliana rely on ACS2 and ACS6 gene expression

    PubMed Central

    2014-01-01

    Background Anthropogenic activities cause metal pollution worldwide. Plants can absorb and accumulate these metals through their root system, inducing stress as a result of excess metal concentrations inside the plant. Ethylene is a regulator of multiple plant processes, and is affected by many biotic and abiotic stresses. Increased ethylene levels have been observed after exposure to excess metals but it remains unclear how the increased ethylene levels are achieved at the molecular level. In this study, the effects of cadmium (Cd) exposure on the production of ethylene and its precursor 1-aminocyclopropane-1-carboxylic acid (ACC), and on the expression of the ACC Synthase (ACS) and ACC Oxidase (ACO) multigene families were investigated in Arabidopsis thaliana. Results Increased ethylene release after Cd exposure was directly measurable in a system using rockwool-cultivated plants; enhanced levels of the ethylene precursor ACC together with higher mRNA levels of ethylene responsive genes: ACO2, ETR2 and ERF1 also indicated increased ethylene production in hydroponic culture. Regarding underlying mechanisms, it was found that the transcript levels of ACO2 and ACO4, the most abundantly expressed members of the ACO multigene family, were increased upon Cd exposure. ACC synthesis is the rate-limiting step in ethylene biosynthesis, and transcript levels of both ACS2 and ACS6 showed the highest increase and became the most abundant isoforms after Cd exposure, suggesting their importance in the Cd-induced increase of ethylene production. Conclusions Cadmium induced the biosynthesis of ACC and ethylene in Arabidopsis thaliana plants mainly via the increased expression of ACS2 and ACS6. This was confirmed in the acs2-1acs6-1 double knockout mutants, which showed a decreased ethylene production, positively affecting leaf biomass and resulting in a delayed induction of ethylene responsive gene expressions without significant differences in Cd contents between wild-type and

  11. Investigation of the micropolarity in reverse micelles of nonionic poly(ethylene oxide) surfactants using 4-nitropyridine-N-oxide as absorption probe.

    PubMed

    Bandula, Rodica; Vasilescu, Marilena; Lemmetyinen, Helge

    2005-07-15

    The micropolarities of the reverse micelle (RM) interior of nonionic poly(ethylene oxide) surfactants of the alkyl ether type (poly(ethylene oxide)[4] lauryl ether (C12E4, Brij 30)), alkyl-aryl ethers (poly(ethylene oxide)[4] nonylphenyl ether (C9PhiE4), poly(ethylene oxide)[5] nonylphenyl ether (C9PhiE5), and poly(ethylene oxide)[5] octylphenyl ether (C8PhiE5)), and poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers (Pluronics P123, F127) were investigated as a function of the water content by applying the absorption probe technique, using 4-nitropyridine-N-oxide (NP) as a probe. The change in the micellar aggregate micropolarity in different solvents (cyclohexane, decane, n-butanol, and n-butyl acetate) at various water contents has been investigated. The research was focused on the determination of the effects of surfactant structure and solvent type on the hydration degrees of the PEO chains in the region at the core limit, where the NP probe was located. All results regarding the polarities in RM and PEO/water calibration mixtures have been expressed in terms of Kosower's Z values, using the linear dependence of E(NP) on Kosower's Z. The PPO/butanol mixtures have also been used for RM in butanol as a reference system. The data revealed that local polarity in RM is dependent on the surfactant type, block copolymer composition, solvent nature, and water content. At the same water content, the results clearly indicate a lower hydration degree of triblock copolymers, as compared to the surfactants of the alkyl ether and alkyl-aryl ether type, but for P123 and F127 Pluronics in n-butanol the hydration is higher owing to the behavior of butanol as cosurfactant and to its hydration. PMID:15925636

  12. Understanding Variability To Reduce the Energy and GHG Footprints of U.S. Ethylene Production.

    PubMed

    Yao, Yuan; Graziano, Diane J; Riddle, Matthew; Cresko, Joe; Masanet, Eric

    2015-12-15

    Recent growth in U.S. ethylene production due to the shale gas boom is affecting the U.S. chemical industry's energy and greenhouse gas (GHG) emissions footprints. To evaluate these effects, a systematic, first-principles model of the cradle-to-gate ethylene production system was developed and applied. The variances associated with estimating the energy consumption and GHG emission intensities of U.S. ethylene production, both from conventional natural gas and from shale gas, are explicitly analyzed. A sensitivity analysis illustrates that the large variances in energy intensity are due to process parameters (e.g., compressor efficiency), and that large variances in GHG emissions intensity are due to fugitive emissions from upstream natural gas production. On the basis of these results, the opportunities with the greatest leverage for reducing the energy and GHG footprints are presented. The model and analysis provide energy analysts and policy makers with a better understanding of the drivers of energy use and GHG emissions associated with U.S. ethylene production. They also constitute a rich data resource that can be used to evaluate options for managing the industry's footprints moving forward. PMID:26523461

  13. A quantitative evaluation of ethylene production in the recombinant cyanobacterium Synechocystis sp. PCC 6803 harboring the ethylene-forming enzyme by membrane inlet mass spectrometry.

    PubMed

    Zavřel, Tomáš; Knoop, Henning; Steuer, Ralf; Jones, Patrik R; Červený, Jan; Trtílek, Martin

    2016-02-01

    The prediction of the world's future energy consumption and global climate change makes it desirable to identify new technologies to replace or augment fossil fuels by environmentally sustainable alternatives. One appealing sustainable energy concept is harvesting solar energy via photosynthesis coupled to conversion of CO2 into chemical feedstock and fuel. In this work, the production of ethylene, the most widely used petrochemical produced exclusively from fossil fuels, in the model cyanobacterium Synechocystis sp. PCC 6803 is studied. A novel instrumentation setup for quantitative monitoring of ethylene production using a combination of flat-panel photobioreactor coupled to a membrane-inlet mass spectrometer is introduced. Carbon partitioning is estimated using a quantitative model of cyanobacterial metabolism. The results show that ethylene is produced under a wide range of light intensities with an optimum at modest irradiances. The results allow production conditions to be optimized in a highly controlled setup. PMID:26708481

  14. INFLUENCE OF LIGHT ON OZONE-INDUCED 1-AMINOCYCLOPROPANE-1-CARBOXYLIC ACID AND ETHYLENE PRODUCTION FROM INTACT PLANTS

    EPA Science Inventory

    The influence of light on ozone-induced ethylene production from intact soybean (Glycine max L. Merr. cv. Dare) and tomato (Lycopersicon esculentum Mill. cv. Roma) plants was investigated. Ozone-induced stress ethylene production was 2.6-fold greater from dark-than light-incubate...

  15. Transient kinetic modeling of the ethylene and carbon monoxide oxidation over a commercial automotive exhaust gas catalyst

    SciTech Connect

    Harmsen, J.M.A.; Hoebink, J.H.B.J.; Schouten, J.C.

    2000-03-01

    The transient kinetics of ethylene oxidation by oxygen over a commercial Pt/Rh/CeO{sub 2}/{gamma}-Al{sub 2}O{sub 3} three-way catalyst were modeled. Experiments were carried out in a fixed-bed microreactor with two separate inlets, enabling alternate feeding of ethylene and oxygen with frequencies up to {1/4} Hz. The experimental conditions resemble the cold-start period of an Otto engine in a car. Two types of adsorbed ethylene species seem to exist. A selective catalyst deactivation for oxygen adsorption, due to deposition of carbonaceous species, was found. A kinetic model was developed, based on elementary reaction steps, that allows one to describe the experiments quantitatively. Furthermore, this model was combined with the published model for transient carbon monoxide oxidation over the same catalyst, which enables one to predict the results of simultaneous ethylene and carbon monoxide oxidation. Both components react in rather distinct zones, with ethylene being converted only when carbon monoxide oxidation is almost complete.

  16. Atomistic simulation of CO2 solubility in poly(ethylene oxide) oligomers

    NASA Astrophysics Data System (ADS)

    Hong, Bingbing; Panagiotopoulos, Athanassios Z.

    2014-06-01

    We have performed atomistic molecular dynamics simulations coupled with thermodynamic integration to obtain the excess chemical potential and pressure-composition phase diagrams for CO2 in poly(ethylene oxide) oligomers. Poly(ethylene oxide) dimethyl ether, CH3O(CH2CH2O)nCH3 (PEO for short) is a widely applied physical solvent that forms the major organic constituent of a class of novel nanoparticle-based absorbents. Good predictions were obtained for pressure-composition-density relations for CO2 + PEO oligomers (2 ≤ n ≤ 12), using the Potoff force field for PEO [J. Chem. Phys. 136, 044514 (2012)] together with the TraPPE model for CO2 [AIChE J. 47, 1676 (2001)]. Water effects on Henry's constant of CO2 in PEO have also been investigated. Addition of modest amounts of water in PEO produces a relatively small increase in Henry's constant. Dependence of the calculated Henry's constant on the weight percentage of water falls on a temperature-dependent master curve, irrespective of PEO chain length.

  17. Molecular dynamics simulations of silica nanoparticles grafted with poly(ethylene oxide) oligomer chains.

    PubMed

    Hong, Bingbing; Panagiotopoulos, Athanassios Z

    2012-03-01

    A molecular model of silica nanoparticles grafted with poly(ethylene oxide) oligomers has been developed for predicting the transport properties of nanoparticle organic-hybrid materials (NOHMs). Ungrafted silica nanoparticles in a medium of poly(ethylene oxide) oligomers were also simulated to clarify the effect of grafting on the dynamics of nanoparticles and chains. The model approximates nanoparticles as solid spheres and uses a united-atom representation for chains, including torsional and bond-bending interactions. The calculated viscosities from Green-Kubo relationships and temperature extrapolation are of the same order of magnitude as experimental data but show a smaller activation energy relative to real NOHMs systems. Grafted systems have higher viscosities, smaller diffusion coefficients, and slower chain dynamics than the ungrafted ones at high temperatures. At lower temperatures, grafted systems exhibit faster dynamics for both nanoparticles and chains relative to ungrafted systems, because of lower aggregation of particles and enhanced correlations between nanoparticles and chains. This agrees with the experimental observation that NOHMs have liquidlike behavior in the absence of a solvent. For both grafted and ungrafted systems at low temperatures, increasing chain length reduces the volume fraction of nanoparticles and accelerates the dynamics. However, at high temperatures, longer chains slow down nanoparticle diffusion. From the Stokes-Einstein relationship, it was determined that the coarse-grained treatment of nanoparticles leads to slip on the nanoparticle surfaces. Grafted systems obey the Stokes-Einstein relationship over the temperature range simulated, but ungrafted systems display deviations from it. PMID:22243140

  18. Specificity, accuracy, and interpretation of measurements of ethylene oxide gas concentrations during sterilization using a microwave spectrometer

    NASA Astrophysics Data System (ADS)

    Zhu, Z.; Matthews, I. P.; Dickinson, W.

    1997-07-01

    This article reports the update in the design of a microwave spectrometer for measuring concentrations of ethylene oxide gas during sterilization. The specificity of the measurement (absorption line at 23.134 GHz) using the spectrometer has been found to be virtually 100%. A great number of calibrations have been conducted in the range of concentrations 100% to 40% of ethylene oxide gas at intervals of -10% in order to determine the accuracy of the spectrometer. It was found that the maximum standard deviation from the regression curve was 1.2% full scale (0%-100%). A mathematical model based on a diffusion equation has been developed and was used to interpret the real time measurement data during sterilization. Numerical simulation using this model has demonstrated that it is possible to predict the dynamic distributions of ethylene oxide concentration within the load being sterilized.

  19. On the elastic properties of single-walled carbon nanotubes/poly(ethylene oxide) nanocomposites using molecular dynamics simulations.

    PubMed

    Rouhi, S; Alizadeh, Y; Ansari, R

    2016-01-01

    Molecular dynamics simulations are used to study the physical and mechanical properties of single-walled carbon nanotubes/poly(ethylene oxide) nanocomposites. The effects of nanotube atomic structure, diameter, and volume fraction on the polymer density distribution, polymer atom distribution, stress-strain curves of nanocomposites and Young's, and shear moduli of single-walled carbon nanotubes/poly(ethylene oxide) nanocomposites are explored. It is shown that the density of polymer, surrounding the nanotube surface, has a peak near the nanotube surface. However, increasing distance leads to dropping it to the value near the density of pure polymer. It is seen that for armchair nanotubes, the average polymer atoms distances from the single-walled carbon nanotubes are larger than the polymer atom distance from zigzag nanotubes. It further is shown that zigzag nanotubes are better candidates to reinforce poly (ethylene oxide) than their armchair counterparts. PMID:26791535

  20. Flash methanolysis of coal for the synthesis and production of ethylene, benzene and liquid hydrocarbons

    SciTech Connect

    Steinberg, M.; Fallon, P.T.

    1981-12-01

    On rapidly reacting methane with coal at short residence times (< 10 sec) in an entrained tubular reactor at temperatures in the range of 825/sup 0/ to 900/sup 0/C and pressures of 50 to 100 psi, significant yields of ethylene, BTX, and light oils are formed. The yield of ethylene increases strongly with decreasing pressure. There appears to be no net consumption of methane. A preliminary economic analysis of a process for production of the above feedstocks from coal, recycling the methane and using the residual char as a boiler fuel indicates a very ample return on the investment.

  1. MPK3/MPK6 are involved in iron deficiency-induced ethylene production in Arabidopsis

    PubMed Central

    Ye, Lingxiao; Li, Lin; Wang, Lu; Wang, Shoudong; Li, Sen; Du, Juan; Zhang, Shuqun; Shou, Huixia

    2015-01-01

    Iron (Fe) is an essential micronutrient that participates in various biological processes important for plant growth. Ethylene production induced by Fe deficiency plays important roles in plant tolerance to stress induced by Fe deficiency. However, the activation and regulatory mechanisms of 1-Aminocyclopropane-1-carboxylic acid synthase (ACS) genes in this response are not clear. In this study, we demonstrated that Fe deficiency increased the abundance of ACS2, ACS6, ACS7, and ACS11 transcripts in both leaves and roots as well as the abundance of ACS8 transcripts in leaves and ACS9 transcripts in roots. Furthermore, we investigated the role of mitogen-activated protein kinase 3 and 6 (MPK3/MPK6)-regulated ACS2/6 activation in Fe deficiency-induced ethylene production. Our results showed that MPK3/MPK6 transcript abundance and MPK3/MPK6 phosphorylation are elevated under conditions of Fe deficiency. Furthermore, mpk3 and mpk6 mutants show a lesser induction of ethylene production under Fe deficiency and a greater sensitivity to Fe deficiency. Finally, in mpk3, mpk6, and acs2 mutants under conditions of Fe deficiency, induction of transcript expression of the Fe-deficiency response genes FRO2, IRT1, and FIT is partially compromised. Taken together, our results suggest that the MPK3/MPK6 and ACS2 are part of the Fe starvation-induced ethylene production signaling pathway. PMID:26579185

  2. Poly(ethylene oxide)-sodium polyiodide conductors: characterization, electrical conductivity, and photoresponse

    SciTech Connect

    Hardy, L.C.; Shriver, D.F.

    1986-05-28

    The complexes of poly(ethylene oxide) with sodium polyiodide are electronic conductors. The level of conductivity at room temperature is 2 to 3 orders of magnitude greater than that of simple quaternary ammonium polyiodide salts. Raman spectroscopy indicates that the polyiodide species formed in the polymeric material depends upon the salt concentration in the polymer as well as the iodine to sodium ion ratio. High conductivity is associated with the appearance of a polyiodide species having a resonance-enhanced Raman feature at ca. 171 cm/sup -1/. A photovoltaic effect is observed when the polyiodide-containing polymer is sandwiched between indium-tin oxide glass and platinum electrodes and then illuminated through the ITO. The sign of the photoinduced potential indicates that the photovoltaic effect arises from a recombination of electrons from ITO with holes in the polyiodide valance bond.

  3. Protein nanorings organized by poly(styrene-block-ethylene oxide) self-assembled thin films

    NASA Astrophysics Data System (ADS)

    Malmström, Jenny; Wason, Akshita; Roache, Fergus; Yewdall, N. Amy; Radjainia, Mazdak; Wei, Shanghai; Higgins, Michael J.; Williams, David E.; Gerrard, Juliet A.; Travas-Sejdic, Jadranka

    2015-11-01

    This study explores the use of block copolymer self-assembly to organize Lsmα, a protein which forms stable doughnut-shaped heptameric structures. Here, we have explored the idea that 2-D crystalline arrays of protein filaments can be prepared by stacking doughnut shaped Lsmα protein into the poly(ethylene oxide) blocks of a hexagonal microphase-separated polystyrene-b-polyethylene oxide (PS-b-PEO) block copolymer. We were able to demonstrate the coordinated assembly of such a complex hierarchical nanostructure. The key to success was the choice of solvent systems and protein functionalization that achieved sufficient compatibility whilst still promoting assembly. Unambiguous characterisation of these structures is difficult; however AFM and TEM measurements confirmed that the protein was sequestered into the PEO blocks. The use of a protein that assembles into stackable doughnuts offers the possibility of assembling nanoscale optical, magnetic and electronic structures.This study explores the use of block copolymer self-assembly to organize Lsmα, a protein which forms stable doughnut-shaped heptameric structures. Here, we have explored the idea that 2-D crystalline arrays of protein filaments can be prepared by stacking doughnut shaped Lsmα protein into the poly(ethylene oxide) blocks of a hexagonal microphase-separated polystyrene-b-polyethylene oxide (PS-b-PEO) block copolymer. We were able to demonstrate the coordinated assembly of such a complex hierarchical nanostructure. The key to success was the choice of solvent systems and protein functionalization that achieved sufficient compatibility whilst still promoting assembly. Unambiguous characterisation of these structures is difficult; however AFM and TEM measurements confirmed that the protein was sequestered into the PEO blocks. The use of a protein that assembles into stackable doughnuts offers the possibility of assembling nanoscale optical, magnetic and electronic structures. Electronic supplementary

  4. Type I allergic hypersensitivity reactions due to ethylene oxide sterilised leucocyte filters in patients with thalassaemia: report of four cases.

    PubMed

    Belen, Burcu; Polat, Meltem

    2015-01-01

    Ethylene oxide (EO) is a highly reactive gas used in sterilisation of heat sensitive medical devices, such as infusion sets, cannulae, intubation materials, ventriculoperitoneal shunts, dialysis catheters and stents. Allergic reactions due to EO have been reported in haemodialysis patients, patients undergoing extracorporeal photopheresis and donors of plasmapheresis. Clinical manifestations vary considerably and generally do not allow differentiation between IgE-mediated anaphylaxis and anaphylactoid reactions. We report four patients with thalassaemia who experienced anaphylaxis during transfusion due to ethylene oxide sterilised leucocyte filters. The aim of this report is to highlight the fact that frequently transfused patients can have allergic reactions due to EO particles left in leucocyte filters. PMID:25725028

  5. Microwave Enhanced Direct Cracking of Hydrocarbon Feedstock for Energy Efficient Production of Ethylene and Propylene.

    SciTech Connect

    Shulman, Holly; Fall, Morgana; Wagner, Eric; Bowlin, Ricardo

    2012-02-13

    This project demonstrated microwave cracking of ethane with good product conversion and ethylene selectivity, with a short residence time ({approx}0.001 sec). The laboratory scale equipment was designed and built, along with concept designs for larger scale implementation. The system was operated below atmospheric pressures, in the range of 15-55 torr, with argon as a carrier gas. The measured products included hydrogen, methane, acetylene, and ethylene. The results followed similar trends to those predicted by the modeling software SPYRO{reg_sign}, with the exception that the microwave appeared to produce slightly lower amounts of ethylene and methane, although enhanced analytical analysis should reduce the difference. Continued testing will be required to verify these results and quantify the energy consumption of microwave vs. conventional. The microwave cracking process is an attractive option due to the possibility of selectively heating the reaction volume rather than the reactor walls, which may allow novel reactor designs that result in more efficient production of ethylene. Supplemental studies are needed to continue the laboratory testing and refine processing parameters.

  6. New Aptes Cross-linked Polymers from Poly(ethylene oxide)s and Cyanuric Chloride for Lithium Batteries

    NASA Technical Reports Server (NTRS)

    Tigelaar, Dean M.; Meador, Mary Ann B.; Kinder, James D.; Bennett, William R.

    2005-01-01

    A new series of polymer electrolytes for use as membranes for lithium batteries are described. Electrolytes were made by polymerization between cyanuric chloride and diamino-terminated poly(ethylene oxide)s, followed by cross-linking via a sol-gel process. Thermal analysis and lithium conductivity of freestanding polymer films were studied. The effects of several variables on conductivity were investigated, such as length of backbone PEO chain, length of branching PEO chain, extent of branching, extent of cross-linking, salt content, and salt counterion. Polymer films with the highest percentage of PEO were found to be the most conductive, with a maximum lithium conductivity of 3.9 x 10(exp -5) S/cm at 25 C. Addition of plasticizer to the dry polymers increased conductivity by an order of magnitude.

  7. Poly(ethylene glycol) dicarboxylate/poly(ethylene oxide) hydrogel film co-crosslinked by electron beam irradiation as an anti-adhesion barrier.

    PubMed

    Haryanto; Singh, Deepti; Han, Sung Soo; Son, Jun Hyuk; Kim, Seong Cheol

    2015-01-01

    The cross-linked poly(ethylene glycol) dicarboxylate (PEGDC)/poly(ethylene oxide) (PEO) and poly(ethylene glycol) dimethacrylate (PEGDMA)/(PEO) hydrogels were developed for possible biomedical applications such as an anti-adhesion barrier. Various contents of PEGDC/PEO film were irradiated using an electron beam with various beam intensities in order to obtain various degrees of crosslinked hydrogels. The optimum dose (300 kGy) and total crosslinker content of 10% were used to prepare crosslinked hydrogel films with three different compositions (10% PEGDC, 10% PEGDMA, 5% PEGDC-5% PEGDMA). Among them, 10% PEGDC hydrogel film exhibited the highest elongation at break (69.33±6.87%) with high mechanical strength. 10% PEGDC hydrogel film showed the lowest hemolysis activity (6.03±0.01%) and the highest tissue adherence (75.67±1.15 cN). The result also indicated that the carboxyl groups in PEGDC affect the tissue adherence of hydrogel films via H-bonding interactions. In animal studies, 10% PEGDC anti-adhesion hydrogel film degraded within 3 weeks and demonstrated better anti-adhesive effect compared to Guardix-SG®. PMID:25491977

  8. A study on optical properties of poly (ethylene oxide) based polymer electrolyte with different alkali metal iodides

    NASA Astrophysics Data System (ADS)

    Rao, B. Narasimha; Suvarna, R. Padma

    2016-05-01

    Polymer electrolytes were prepared by adding poly (ethylene glycol) dimethyl ether (PEGDME), TiO2 (nano filler), different alkali metal iodide salts RI (R+=Li+, Na+, K+, Rb+, Cs+) and I2 into Acetonitrile gelated with Poly (ethylene oxide) (PEO). Optical properties of poly (ethylene oxide) based polymer electrolytes were studied by FTIR, UV-Vis spectroscopic techniques. FTIR spectrum reveals that the alkali metal cations were coordinated to ether oxygen of PEO. The optical absorption studies were made in the wavelength range 200-800 nm. It is observed that the optical absorption increases with increase in the radius of alkali metal cation. The optical band gap for allowed direct transitions was evaluated using Urbach-edges method. The optical properties such as optical band gap, refractive index and extinction coefficient were determined. The studied polymer materials are useful for solar cells, super capacitors, fuel cells, gas sensors etc.

  9. Ethylene oxide's role as a reactive agent during sterilization: effects of polymer composition and device architecture.

    PubMed

    Phillip, Edward; Murthy, N Sanjeeva; Bolikal, Durgadas; Narayanan, Pallassana; Kohn, Joachim; Lavelle, Linda; Bodnar, Stanko; Pricer, Kurt

    2013-05-01

    Sterilization conditions need to be optimized to effectively neutralize the bioburden while using short exposure times for minimizing the changes in chemical composition, material properties and device architecture. Towards this goal, effects of ethylene oxide (EtO) exposure parameters such as time, temperature, humidity, and EtO concentration on the polymer properties were investigated by monitoring the changes in composition, and the morphology of different types of structures in a family of poly(ethylene glycol) (PEG)-containing tyrosine-derived polycarbonates. EtO was found to esterify the carboxyl groups present in the desaminotyrosyl-tyrosine groups. Sterilization under conditions more severe than those normally used reduced the glass transition temperature (Tg) and the molecular weight of the polymers, and the presence of PEG in the polymer enhanced this effect. Furthermore, electron micrographs showed that EtO sterilization cycle conditions, even those considered "mild," were found to damage the fragile structures such as those found in electrospun mats and porous scaffolds. Our study shows that the presence of EtO-susceptible groups, fusible architecture, and surface morphology should be taken into account in choosing the appropriate EtO sterilization conditions. PMID:23296710

  10. Health-hazard evaluation report HETA-87-207-1845, University of Colorado, Health Science Center, Denver, Colorado. [Ethylene oxide exposure

    SciTech Connect

    Nichting, A.T.; Hales, T.R.; Gunter, B.J.

    1987-10-01

    A study of possible hospital employee exposure to ethylene oxide was undertaken. Employees had complained of headaches and possible neurological problems. A personal breathing-zone sample collected from the sterilizer operator showed levels of ethylene oxide at the limit of quantitation, 0.02mg/cu m. In sterilizer and mechanical-access-room samples, ethylene oxide was detected ranging up to 0.2mg/cu m levels. The authors conclude that a potential for exposure to ethylene oxide exists for workers in the sterilizer room. The authors recommend that efforts be continued to keep ethylene oxide levels as low as possible and to check for possible leaks in the system. Effective ventilation controls should be established, and a warning system should be installed in the mechanical access room. Respirators, protective clothing, training for employees, safety meetings, and medical evaluations for personnel were all included in the recommendations following the investigation.

  11. EFFECTS OF CHEMICAL PROCESSING AND OXIDE ETHYLENE STERILIZATION ON CORTICAL AND CANCELLOUS RAT BONE: A LIGHT AND ELECTRON SCANNING MICROSCOPY STUDY

    PubMed Central

    Castiglia, Marcello Teixeira; da Silva, Juliano Voltarelli F.; Frezarim Thomazini, José Armendir; Volpon, José Batista

    2015-01-01

    To evaluate, under microscopic examination, the structural changes displayed by the trabecular and cortical bones after being processed chemically and sterilized by ethylene oxide. Methods: Samples of cancellous and cortical bones obtained from young female albinus rats (Wistar) were assigned to four groups according to the type of treatment: Group I- drying; Group II- drying and ethylene oxide sterilization; III- chemical treatment; IV- chemical treatment and ethylene oxide sterilization. Half of this material was analyzed under ordinary light microscope and the other half using scanning electron microscopy. Results: In all the samples, regardless the group, there was good preservation of the general morphology. For samples submitted to the chemical processing there was better preservation of the cellular content, whereas there was amalgamation of the fibres when ethylene oxide was used. Conclusion: Treatment with ethylene oxide caused amalgamation of the fibers, possibly because of heating and the chemical treatment contributed to a better cellular preservation of the osseous structure. PMID:26998450

  12. The flash pyrolysis and methanolysis of biomass (wood) for production of ethylene, benzene and methanol

    SciTech Connect

    Steinberg, M.; Fallon, P.T.; Sundaram, M.S.

    1990-02-01

    The process chemistry of the flash pyrolysis of biomass (wood) with the reactive gases, H{sub 2} and CH{sub 4} and with the non-reactive gases He and N{sub 2} is being determined in a 1 in. downflow tubular reactor at pressures from 20 to 1000 psi and temperatures from 600 to 1000{degrees}C. With hydrogen, flash hydropyrolysis leads to high yields of methane and CO which can be used for SNG and methanol fuel production. With methane, flash methanolysis leads to high yields of ethylene, benzene and CO which can be used for the production of valuable chemical feedstocks and methanol transportation fuel. At reactor conditions of 50 psi and 1000{degrees}C and approximately 1 sec residence time, the yields based on pine wood carbon conversion are up to 25% for ethylene, 25% for benzene, and 45% for CO, indicating that over 90% of the carbon in pine is converted to valuable products. Pine wood produces higher yields of hydrocarbon products than Douglas fir wood; the yield of ethylene is 2.3 times higher with methane than with helium or nitrogen, and for pine, the ratio is 7.5 times higher. The mechanism appears to be a free radical reaction between CH{sub 4} and the pyrolyzed wood. There appears to be no net production or consumption of methane. A preliminary process design and analysis indicates a potentially economical competitive system for the production of ethylene, benzene and methanol based on the methanolysis of wood. 10 refs., 18 figs., 1 tab.

  13. Effects of Silica Nanostructures in Poly(ethylene oxide)-Based Composite Polymer Electrolytes.

    PubMed

    Mohanta, Jagdeep; Anwar, Shahid; Si, Satyabrata

    2016-06-01

    The present work describes the synthesis of some poly(ethylene oxide)-based nanocomposite polymer electrolyte films using various silica nanostructures as the inorganic filler by simple solution mixing technique, in which the nature of the silica nanostructures play a vital role in modulating their electrochemical performances at room temperature. The silica nanostructures are prepared by ammonical hydrolysis of tetraethyl orthosilicate following the modified St6ber method. The resulting films are characterized by X-ray diffraction and differential scanning calorimeter to study their crystallinity. Room temperature AC impedance spectroscopy is utilized to determine the Li+ ion conductivity of the resulting films. The observed conductivity values of various NCPE films depend on the nature of silica filling as well as on their surface characteristics and also on the varying PEO-Li+ ratio, which is observed to be in the order of 10(-7)-10(-6) S cm(-1). PMID:27427686

  14. Effect of molecular weight on ion diffusion and transference number in poly(ethylene oxide)

    NASA Astrophysics Data System (ADS)

    Timachova, Ksenia; Balsara, Nitash

    2015-03-01

    Solid polymer electrolytes are of great interest for their potential use in high specific energy, solid-state batteries, however, salt transport properties in polymer electrolytes have not been comprehensively addressed over a wide range of molecular weights. Poly(ethylene oxide) (PEO) has been the most widely studied polymer electrolyte due to its high solvation of lithium salts and low glass transition temperature. This study presents measurements of the transport properties of lithium bis(trifluoromethanesulfone)imide (LiTFSI) in PEO at both the high concentration present in functional electrolytes and in the dilute limit for a large range of PEO molecular weights. Individual diffusion coefficients of the Li + and TFSI- ions were measured using pulsed-field gradient nuclear magnetic resonance and the cation transference number was calculated. The diffusion coefficients, transference number, and conductivity as a function of molecular weight and salt concentration provide a complete set of transport properties for PEO.

  15. SHI induced modification in structural, optical, dielectric and thermal properties of poly ethylene oxide films

    NASA Astrophysics Data System (ADS)

    Patel, Gnansagar B.; Bhavsar, Shilpa; Singh, N. L.; Singh, F.; Kulriya, P. K.

    2016-07-01

    Poly ethylene oxide (PEO) films were synthesized by solution cast method. These self-standing films were exposed with 60 MeV C+5 ion and 100 MeV Ni+7 ion at different fluences. SHI induced effect was investigated by employing various techniques. The crystalline size decreased upon irradiation as observed from XRD analysis. FTIR analysis reveals the decrement in the peak intensity upon irradiation. Tauc's method was used to determine the optical band gap (Eg), which shows decreasing trends with increase of fluence. The dielectric properties were investigated in the frequency range 10 Hz to 10 MHz for unirradiated and irradiated films. The dielectric constant remains same for the broad-spectrum of frequency and increases at lower frequency. The dielectric loss also moderately influence as a function of frequency due to irradiation. DSC analysis validated the results of XRD. Scanning electron microscopy (SEM) reveals that there is significant change in the surface morphology due to irradiation.

  16. Antibacterial effects of electrospun chitosan/poly(ethylene oxide) nanofibrous membranes loaded with chlorhexidine and silver.

    PubMed

    Song, Jiankang; Remmers, Stefan J A; Shao, Jinlong; Kolwijck, Eva; Walboomers, X Frank; Jansen, John A; Leeuwenburgh, Sander C G; Yang, Fang

    2016-07-01

    To prevent percutaneous device associated infections (PDAIs), we prepared electrospun chitosan/poly(ethylene oxide) (PEO) nanofibrous membrane containing silver nanoparticles as an implantable delivery vehicle for the dual release of chlorhexidine and silver ions. We observed that the silver nanoparticles were distributed homogeneously throughout the fibers, and a fast release of chlorhexidine in 2days and a sustained release of silver ions for up to 28days. The antibacterial efficacy of the membranes against Staphylococcus aureus showed that the membranes exhibited an obvious inhibition zone upon loading with either chlorhexidine (20μg or more per membrane) or AgNO3 (1 and 5wt% to polymer). Furthermore, long-term antibacterial effect up to 4days was verified using membranes containing 5wt% AgNO3. The results suggest that the membranes have strong potential to act as an active antibacterial dressing for local delivery of antibacterial agents to prevent PDAIs. PMID:26970025

  17. Phase Behavior of a Poly(ethylene oxide)-Poly(ethylethylene)/Water/Dodecane System

    NASA Astrophysics Data System (ADS)

    Kossuth, M. B.; Bates, F. S.

    1998-03-01

    Recently, we investigated the phase behavior of a series of low molecular weight poly(ethylene oxide)-poly(ethylethylene) (PEO-PEE) block copolymers in the presence of water (D.A. Hajduk, M.B. Kossuth, M.A. Hillmyer, and F.S. Bates, submitted to J. Phys. Chem. B). These molecules are chemically similar to the C_nEOm surfactants but have molecular weights roughly an order of magnitude greater. PEO is hydrophilic, while PEE is strongly hydrophobic. Current work involves the addition of a third component, dodecane, to create a ternary surfactant/water/oil system. The phase behavior of this system will be discussed and compared to that of chemically similar small molecule surfactants. Noteworthy results include the appearance of a bicontinuous cubic phase, which was not seen in the aqueous solutions, and the relative sizes of the phase windows.

  18. [Recommendation for validation and routine monitoring of sterilization processes with ethylene oxide for medical devices].

    PubMed

    Jakimiak, B; Röhm-Rodowald, E

    1999-01-01

    The European Medical Device Directives specifically address sterilization issues in a number of instances. The European Standards for sterilization of medical devices, especially EN 550, EN 554, EN 556 regulate the manufacture, installation and operation of sterilizers as well as the validation of sterilization processes, on using ethylene oxide (EN 550) or moist heat (EN 554) for sterilization. This recommendation is intended as a source of information for conducting validation according to EN 550 and concomitantly for ensuring that the medical devices reprocessed (cleaned, disinfected, packed, sterilized, stored) in the hospital setting or in other healthcare establishments are endowed with the same level of safety with respect to sterility as that of industrially produced and marketed sterile medical devices. PMID:10474298

  19. [Cytotoxicity of PVC tubes sterilized in ethylene oxide after gamma radiation exposure].

    PubMed

    de Souza, Rafael Queiroz; Graziano, Kazuko Uchikawa; Ikeda, Tamiko Ichikawa; Gonçalves, Cláudia Regina; Cruz, Aurea Silveira

    2013-04-01

    Do materials sterilized using gamma rays become toxic when re-sterilized in ethylene oxide? This question guided the objective of this study, which was to investigate the potential cytotoxic effect of PVC sterilized by gamma radiation and re-sterilized with EO by the agar diffusion method in cell cultures. Nine PVC tubes were subjected to gamma radiation sterilization and were re-sterilized in EO. The tubes were divided into a total of 81 units of analysis that were tested so as to represent the internal and external surfaces and mass of each tube. It was concluded that the PVC materials sterilized in gamma radiation and re-sterilized in EO are not cytotoxic. PMID:23743920

  20. CO2 permeation through poly(amide-6-b-ethylene oxide)-nanosilica membranes

    NASA Astrophysics Data System (ADS)

    Lovineh, Shirin Gh.; Asghari, Morteza; Khanbabaei, Ghader

    2014-11-01

    The organic-inorganic hybrids of poly(amide-6-b-ethylene oxide) (PEBA) and silica utilizing aminopropyltriethoxysilane (APTES) as precursor was prepared via sol-gel process and was compared with neat PEBA. The nanodispersed inorganic network produced in the organic matrix was structurally characterized using Fourier transform infrared (FT-IR) that revealed the existence of different chemical groups corresponding to the silica precursors. The single gas permeability was carried out for neat PEBA and PEBA-nano silica (10 wt.% precursor) membranes. CO2 permeability for the neat polymer membrane was higher than the nano-composite membrane and increased with pressure. Adding 10 wt.% of nanosilica filler into the polymeric matrix caused CO2 permeability to decrease.

  1. Poly(ethylene oxide)/clay nanaocomposites: Thermal and mechanical properties

    NASA Astrophysics Data System (ADS)

    Ejder-Korucu, Mehtap; Gürses, Ahmet; Karaca, Semra

    2016-08-01

    Poly(ethylene oxide) (PEO)/clay nanocomposites were prepared by a solution intercalation method using chloroform as a solvent. The nanocomposites were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and also investigation of some mechanical properties of the composites. Formation of nanocomposite was confirmed by XRD analysis. The increasing tendency of exfoliation degree with an increase in clay content may be attributed to easier diffusion of PEO chains to interlayer regions. An increase in PEO crystallinity in case of nanocomposite, was confirmed by an increase in the heat of melting as indicated by DSC. Improvement in tensile properties in all respect was observed for nanocomposites with clay content.

  2. Effects of temperature and relative humidity on biological indicators used for ethylene oxide sterilization.

    PubMed Central

    Oxborrow, G S; Placencia, A M; Danielson, J W

    1983-01-01

    A study was made to determine the effects of temperature and moisture on the D-value of a common biological indicator. Relative humidity (RH) was varied between 10 and 70% in increments of 10%, and temperature was varied between 30 and 70 degrees C in increments of 10 degrees C. Temperature was found to have a pronounced effect on the D-value. At 60% RH, the D-value varied from 15.0 min at 30 degrees C to 1.1 min at 70 degrees C. When RH was plotted against the average D-value at the various temperatures, the temperature curves at or above 50 degrees C were more erratic and the RH had a significant effect. The study showed that temperature and RH must be controlled if biological indicators are to be properly calibrated for use in ethylene oxide sterilization. PMID:6402979

  3. Structural conformation in a poly (ethylene oxide) film obta inedfrom X-ray emission spectroscopy (XES)

    SciTech Connect

    Kashtanov, S.; Zhuang, G.V.; Augustsson, A.; Guo, J.-H.; Nordgren, J.; Luo, Y.; Ross, P.N.

    2007-03-16

    The electronic structure of poly(ethylene oxide) (PEO) in a thin (< 1 {micro}) film sample was experimentally probed by X-ray emission spectroscopy. The emission spectra from this film were much sharper with more resolved fine structure than the spectra from the bulk polymer from which it was cast. Both non-resonant and resonant X-ray emission spectra were simulated using density functional theory (DFT) applied to four different models representing different conformations in the polymer. Calculated spectra were compared with experimental results for the PEO film. It was found that the best fit was obtained with the polymer conformation in PEO electrolytes from which the salt (LiMF6, M=P, As, or Sb) had been removed. This conformation is different from that in the crystalline bulk polymer and implies that film casting, commonly used to form electrolytes for Li polymer batteries, induces the same conformation in the polymer with or without the salt present.

  4. Facile synthesis of porous worm-like Pd nanotubes with high electrocatalytic activity and stability towards ethylene glycol oxidation.

    PubMed

    Feng, Jiu-Ju; Zhou, Dan-Ling; Xi, Huan-Xiang; Chen, Jian-Rong; Wang, Ai-Jun

    2013-08-01

    A facile method was developed for large-scale preparation of porous worm-like Pd nanotubes based on the reduction of PdO nanotubes, which were obtained by calcining the complex precipitate of [Pd(dimethylglyoxime)2]n. The Pd catalyst showed excellent electrocatalytic activity and stability towards ethylene glycol oxidation. PMID:23817778

  5. 78 FR 44117 - Notice of a Public Comment Period on the Draft IRIS Carcinogenicity Assessment for Ethylene Oxide

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-23

    ... Carcinogenicity of Ethylene Oxide'' (EPA/635/R-13/128a) and on the draft peer review charge questions. The draft assessment and draft peer review charge questions were prepared by the National Center for Environmental... review charge questions begins on the day EPA posts the draft assessment and the draft peer review...

  6. Durability of amide N-chloramine biocides to ethylene oxide sterilization.

    PubMed

    Zhao, Nan; Logsetty, Sarvesh; Liu, Song

    2012-01-01

    The objective of this work is to study the stability of three novel topical antimicrobial dressings consisting of amide N-chloramine structures against ethylene oxide sterilization. Cotton gauze samples bonded with one of three amide N-chloramine structures were subjected to standard ethylene oxide (EtO) sterilization. The amounts of amide N-chloramine structures before and after the sterilization were quantified to indicate the stabilities of these amide N-chloramine structures to the sterilization. The samples after sterilization were challenged with a clinical isolate of healthcare-associated multidrug-resistant Escherichia coli. N-Chloramine structure converted from polymethacrylamide (dressing 2) had the highest durability (89.7% retained active chlorine) toward EtO sterilization; that from hydantoin (dressing 3; 86.3% retained active chlorine) followed; and poly(N-chloroacrylamide) (dressing 1) had the lowest (64.0% retained active chlorine). After EtO sterilization, all the samples still reduced E. coli presence at 5 minutes of contact, with dressing 2 retaining a log 6 reduction. The three tested amide N-chloramine structures could all survive EtO sterilization while retaining percentages of active chlorine ranging from 64.0 to 89.7%. Dressing 2 showed the best durability, whereas dressing 1 had the poorest durability. With the remaining amounts of amide N-chloramine structures after EtO sterilization, all the dressings could still reduce E. coli numbers within 5 minutes of contact, and dressing 2 resulted in a log 6 reduction in colony count. PMID:22157019

  7. Ethylene Production by Chilled Cucumbers (Cucumis sativus L.).

    PubMed

    Wang, C Y; Adams, D O

    1980-11-01

    Chilling at 2.5 C accelerated the synthesis of 1-aminocyclopropane-1-carboxylic acid (ACC) and C(2)H(4) production in cucumber fruit. Skin tissue contained higher levels of ACC and was more sensitive to chilling than was cortex tissue. Accumulation of ACC in chilled tissue was detected after 1 day of chilling and remained elevated even after C(2)H(4) production started to decline. These data suggest that ACC synthesis is readily stimulated by chilling, whereas the system that converts ACC to C(2)H(4) is vulnerable to chilling injury. Chilling-induced C(2)H(4) production was inhibited by amino-ethoxyvinylglycine, sodium benzoate, propyl gallate, 2,4-dinitrophenol, carbonyl cyanide m-chlorophenylhydrazone, and cycloheximide. The utilization of methionine for ACC formation and chilling-induced C(2)H(4) biosynthesis was established using l-[3,4-(14)C]methionine. Chilled tissue had a higher capacity to convert l-[3,4-(14)C]methionine to ACC and C(2)H(4) than did nonchilled tissue. PMID:16661538

  8. Ethylene Production by Chilled Cucumbers (Cucumis sativus L.) 1

    PubMed Central

    Wang, Chien Yi; Adams, Douglas O.

    1980-01-01

    Chilling at 2.5 C accelerated the synthesis of 1-aminocyclopropane-1-carboxylic acid (ACC) and C2H4 production in cucumber fruit. Skin tissue contained higher levels of ACC and was more sensitive to chilling than was cortex tissue. Accumulation of ACC in chilled tissue was detected after 1 day of chilling and remained elevated even after C2H4 production started to decline. These data suggest that ACC synthesis is readily stimulated by chilling, whereas the system that converts ACC to C2H4 is vulnerable to chilling injury. Chilling-induced C2H4 production was inhibited by amino-ethoxyvinylglycine, sodium benzoate, propyl gallate, 2,4-dinitrophenol, carbonyl cyanide m-chlorophenylhydrazone, and cycloheximide. The utilization of methionine for ACC formation and chilling-induced C2H4 biosynthesis was established using l-[3,4-14C]methionine. Chilled tissue had a higher capacity to convert l-[3,4-14C]methionine to ACC and C2H4 than did nonchilled tissue. PMID:16661538

  9. Single-Layer Light-Emitting Diodes Using Organometal Halide Perovskite/Poly(ethylene oxide) Composite Thin Films.

    PubMed

    Li, Junqiang; Bade, Sri Ganesh R; Shan, Xin; Yu, Zhibin

    2015-09-16

    Organometal halide perovskite and poly(ethylene oxide) composite thin films are studied. Single-layer light-emitting diodes using the composite thin film sandwiched between indium tin oxide and indium-gallium eutectic alloy exhibit a low turn-on voltage and high brightness because of the ionic conductivity of the composite film and the formation of a p-i-n homojunction. PMID:26247326

  10. Removal of ethylene from air stream by adsorption and plasma-catalytic oxidation using silver-based bimetallic catalysts supported on zeolite.

    PubMed

    Trinh, Quang Hung; Lee, Sang Baek; Mok, Young Sun

    2015-03-21

    Dynamic adsorption of ethylene on 13X zeolite-supported Ag and Ag-M(x)O(y) (M: Co, Cu, Mn, and Fe), and plasma-catalytic oxidation of the adsorbed ethylene were investigated. The experimental results showed that the incorporation of Ag into zeolite afforded a marked enhancement in the adsorptivity for ethylene. The addition of transition metal oxides was found to have a positive influence on the ethylene adsorption, except Fe(x)O(y). The presence of the additional metal oxides, however, appeared to somewhat interrupt the diffusion of ozone into the zeolite micro-pores, leading to a decrease in the plasma-catalytic oxidation efficiency of the ethylene adsorbed there. Among the second additional metal oxides, Fe(x)O(y) was able to reduce the emission of ozone during the plasma-catalytic oxidation stage while keeping a high effectiveness for the oxidative removal of the adsorbed ethylene. The periodical treatment consisting of adsorption followed by plasma-catalytic oxidation may be a promising energy-efficient ethylene abatement method. PMID:25576654

  11. Truffles regulate plant root morphogenesis via the production of auxin and ethylene.

    PubMed

    Splivallo, Richard; Fischer, Urs; Göbel, Cornelia; Feussner, Ivo; Karlovsky, Petr

    2009-08-01

    Truffles are symbiotic fungi that form ectomycorrhizas with plant roots. Here we present evidence that at an early stage of the interaction, i.e. prior to physical contact, mycelia of the white truffle Tuber borchii and the black truffle Tuber melanopsorum induce alterations in root morphology of the host Cistus incanus and the nonhost Arabidopsis (Arabidopsis thaliana; i.e. primary root shortening, lateral root formation, root hair stimulation). This was most likely due to the production of indole-3-acetic acid (IAA) and ethylene by the mycelium. Application of a mixture of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid and IAA fully mimicked the root morphology induced by the mycelium for both host and nonhost plants. Application of the single hormones only partially mimicked it. Furthermore, primary root growth was not inhibited in the Arabidopsis auxin transport mutant aux1-7 by truffle metabolites while root branching was less effected in the ethylene-insensitive mutant ein2-LH. The double mutant aux1-7;ein2-LH displayed reduced sensitivity to fungus-induced primary root shortening and branching. In agreement with the signaling nature of truffle metabolites, increased expression of the auxin response reporter DR5GFP in Arabidopsis root meristems subjected to the mycelium could be observed, confirming that truffles modify the endogenous hormonal balance of plants. Last, we demonstrate that truffles synthesize ethylene from l-methionine probably through the alpha-keto-gamma-(methylthio)butyric acid pathway. Taken together, these results establish the central role of IAA and ethylene as signal molecules in truffle/plant interactions. PMID:19535471

  12. Sucrose importation into laticifers of Hevea brasiliensis, in relation to ethylene stimulation of latex production

    PubMed Central

    Dusotoit-Coucaud, Anaïs; Brunel, Nicole; Kongsawadworakul, Panida; Viboonjun, Unchera; Lacointe, André; Julien, Jean-Louis; Chrestin, Hervé; Sakr, Soulaïman

    2009-01-01

    Background and Aims The major economic product of Hevea brasiliensis is a rubber-containing cytoplasm (latex), which flows out of laticifers (latex cells) when the bark is tapped. The latex yield is stimulated by ethylene. Sucrose, the unique precursor of rubber synthesis, must cross the plasma membrane through specific sucrose transporters before being metabolized in the laticifers. The relative importance of sucrose transporters in determining latex yield is unknown. Here, the effects of ethylene (by application of Ethrel®) on sucrose transporter gene expression in the inner bark tissues and latex cells of H. brasiliensis are described. Methods Experiments, including cloning sucrose transporters, real time RT-PCR and in situ hybridization, were carried out on virgin (untapped) trees, treated or untreated with the latex yield stimulant Ethrel. Key Results Seven putative full-length cDNAs of sucrose transporters were cloned from a latex-specific cDNA library. These transporters belong to all SUT (sucrose transporter) groups and differ by their basal gene expression in latex and inner soft bark, with a predominance of HbSUT1A and HbSUT1B. Of these sucrose transporters, only HbSUT1A and HbSUT2A were distinctly increased by ethylene. Moreover, this increase was shown to be specific to laticifers and to ethylene application. Conclusion The data and all previous information on sucrose transport show that HbSUT1A and HbSUT2A are related to the increase in sucrose import into laticifers, required for the stimulation of latex yield by ethylene in virgin trees. PMID:19567416

  13. Interaction of Light and Ethylene on Stem Gravitropism

    NASA Technical Reports Server (NTRS)

    Harrison, Marcia A.

    1996-01-01

    The major objective of this study was to evaluate light-regulated ethylene production during gravitropic bending in etiolated pea stems. Previous investigations indicated that ethylene production increases after gravistimulation and is associated with the later (counter-reactive) phase of bending. Additionally, changes in the counter-reaction and locus of curvature during gravitropism are greatly influenced by red light and ethylene production. Ethylene production may be regulated by the levels of available precursor (1-aminocyclopropane-l-carboxylic acid, ACC) via its synthesis, conjugation to malonyl-ACC or glutamyl-ACC, or oxidation to ethylene. The regulation of ethylene production by quantifying ACC and conjugated ACC levels in gravistimulated pea stemswas examined. Also measured was the changes in protein and enzyme activity associated with gravitropic curvature by electrophoretic and spectrophotometric techniques. An image analysis system was used to visualize and quantify enzymatic activity and transcriptional products in gravistimulated and red-light treated etiolated pea stem tissues.

  14. Drying of films formed by ordered poly(ethylene oxide)-poly(propylene oxide) block copolymer gels.

    PubMed

    Gu, Zhiyong; Alexandridis, Paschalis

    2005-03-01

    The drying of hydrogel films formed by poly(ethylene oxide)-poly(propylene oxide) (PEO-PPO) block copolymers (Pluronic P105 and Pluronic L64) is investigated at various air relative humidity (RH) conditions in the range 11-94%. These amphiphilic block copolymers self-assemble to form a variety of ordered (lyotropic liquid crystalline) structures as the water content decreases. The amount of water lost increases linearly with the drying time initially (constant rate region, stage I). After this linear region, a falling rate is observed (stage II). The drying rate increases with decreasing RH, thus greatly shortening the drying time. A decrease of the initial film thickness or a decrease in the initial water content shortens the drying time; however, the drying mechanism remains the same. Analysis of the experimental data shows that the hydration level in the Pluronic hydrogel mainly determines the drying rate, rather than the type of ordered structure formed. Two distinct regions (liquid/gel and solid/crystalline) are observed in the drying isotherm for PEO-PPO block copolymers and homopolymer poly(ethylene glycol)s. A model for one-dimensional water diffusion is used to fit the experimental drying results at different RH, initial film thickness, and initial water content conditions. The model accounts for the shrinkage of the film during drying and for a water diffusion coefficient that is a function of the water concentration in the film. For the experimental conditions considered here, the Biot number (Bi) is less than unity and the drying is mainly limited by evaporation at the film surface. The diffusion model is used to obtain information for cases where Bi > 1. PMID:15723476

  15. Development of Iron-Chelating Poly(ethylene terephthalate) Packaging for Inhibiting Lipid Oxidation in Oil-in-Water Emulsions.

    PubMed

    Johnson, David R; Tian, Fang; Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2015-05-27

    Foods such as bulk oils, salad dressings, and nutritionally fortified beverages that are susceptible to oxidative degradation are often packaged in poly(ethylene terephthalate) (PET) bottles with metal chelators added to the food to maintain product quality. In the present work, a metal-chelating active packaging material is designed and characterized, in which poly(hydroxamic acid) (PHA) metal-chelating moieties were grafted from the surface of PET. Biomimetic PHA groups were grafted in a two-step UV-initiated process without the use of a photoinitiator. Surface characterization of the films by attenuated total reflective Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM) suggested successful grafting and conversion of poly(hydroxyethyl acrylate) (PHEA) to PHA chelating moieties from the surface of PET. Colorimetric (ferrozine) and inductively coupled plasma mass spectroscopy (ICP-MS) assays demonstrated the ability of PET-g-PHA to chelate iron in a low-pH (3.0) environment containing a competitive metal chelator (citric acid). Lipid oxidation studies demonstrated the antioxidant activity of PET-g-PHA films in inhibiting iron-promoted oxidation in an acidified oil-in-water (O/W) emulsion model system (pH 3.0). Particle size and ζ-potential analysis indicated that the addition of PET-g-PHA films did not affect the physical stability of the emulsion system. This work suggests that biomimetic chelating moieties can be grafted from PET and effectively inhibit iron-promoted degradation reactions, enabling removal of metal-chelating additives from product formulations. PMID:25985711

  16. Insertion Mechanism of a Poly(ethylene oxide)-poly(butylene oxide) Block Copolymer into a DPPC Monolayer

    SciTech Connect

    Leiske, Danielle L.; Meckes, Brian; Miller, Chad E.; Wu, Cynthia; Walker, Travis W.; Lin, Binhua; Meron, Mati; Ketelson, Howard A.; Toney, Michael F.; Fuller, Gerald G.

    2012-02-06

    Interactions between amphiphilic block copolymers and lipids are of medical interest for applications such as drug delivery and the restoration of damaged cell membranes. A series of monodisperse poly(ethylene oxide)-poly(butylene oxide) (EOBO) block copolymers were obtained with two ratios of hydrophilic/hydrophobic block lengths. We have explored the surface activity of EOBO at a clean interface and under 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayers as a simple cell membrane model. At the same subphase concentration, EOBO achieved higher equilibrium surface pressures under DPPC compared to a bare interface, and the surface activity was improved with longer poly(butylene oxide) blocks. Further investigation of the DPPC/EOBO monolayers showed that combined films exhibited similar surface rheology compared to pure DPPC at the same surface pressures. DPPC/EOBO phase separation was observed in fluorescently doped monolayers, and within the liquid-expanded liquid-condensed coexistence region for DPPC, EOBO did not drastically alter the liquid-condensed domain shapes. Grazing incidence X-ray diffraction (GIXD) and X-ray reflectivity (XRR) quantitatively confirmed that the lattice spacings and tilt of DPPC in lipid-rich regions of the monolayer were nearly equivalent to those of a pure DPPC monolayer at the same surface pressures.

  17. Health Hazard Evaluation Report HETA 83-166-1594, Witco Chemical Corporation, Perth Amboy, New Jersey. [Ethylene oxide, glycols, and adipic acid

    SciTech Connect

    Cummings, C.E.; Roseman, J.

    1985-05-01

    Area and personel air samples were analyzed for ethylene oxide, glycols, and adipic-acid at the Witco Chemical Corporation, Perth Amboy, New Jersey from November to December, 1983 and May, 1984. The evaluation was requested by the union to investigate possible health effects due to polychlorinated biphenyls (PCBs), glycols, and ethylene oxide. The evaluation was assigned to the New Jersey State Department of Health. The authors conclude that health hazards due to ethylene oxide and airborne fatty acid exposures exist. Recommendations include improving ventilation and work practices and implementing an OSHA approved respirator program.

  18. Cytokinin-Induced Ethylene Biosynthesis in Nonsenescing Cotton Leaves

    PubMed Central

    Suttle, Jeffrey C.

    1986-01-01

    The influence of cytokinins on ethylene production was examined using cotton leaf tissues. Treatment of intact cotton (Gossypium hirsutum L. cv LG 102) seedlings with both natural and synthetic cytokinins resulted in an increase in ethylene production by excised leaves. The effectiveness of the cytokinins tested was as follows: thidiazuron ≫ BA ≫ isopentyladenine ≥ zeatin ≫ kinetin. Using 100 micromolar thidiazuron (TDZ), an initial increase in ethylene production was observed 7 to 8 hours post-treatment, reached a maximum by 24 hours and then declined. Inhibitors of 1-aminocyclopropane-1-carboxylic acid (ACC) synthesis and its oxidation to ethylene reduced ethylene production 24 hours post-treatment; however, by 48 hours only inhibitors of ACC oxidation were effective. The increase in ethylene production was accompanied by a massive accumulation of ACC and its acid-labile conjugate. TDZ treatment resulted in a significant increase in the capacity of tissues to oxidize ACC to ethylene. Endogenous levels of methionine remained constant following TDZ treatment. It was concluded that the stimulation of ethylene production in cotton leaves following cytokinin treatment was the result of an increase in both the formation and oxidation of ACC. Images Fig. 4 PMID:16665168

  19. Oxidized Phosphatidylserine: Production and Bioactivities

    PubMed Central

    Matsura, Tatsuya

    2014-01-01

    Recent development of analytical methods for lipid hydroperoxides and preparation of highly pure lipid hydroperoxides have revealed the important new pathophysiological roles of oxidized phospholipids. Generation of reactive oxygen species and subsequent oxidative stress leads to random oxidation of membrane phospholipids. However, recent studies have reported that anionic phospholipid molecules such as phosphatidylserine (PS) and cardiolipin are preferentially oxidized during apoptosis, resulting in efficient apoptosis execution and apoptotic cell clearance by phagocytes. This review is exclusively focused on selective production of oxidized PS (oxPS) during apoptosis as well as the novel roles of oxPS under pathophysiological conditions. PMID:25901098

  20. Effects of microgravity and clinorotation on stress ethylene production in two starchless mutants of Arabidopsis thaliana

    NASA Technical Reports Server (NTRS)

    Gallegos, Gregory L.; Hilaire, Emmanuel M.; Peterson, Barbara V.; Brown, Christopher S.; Guikema, James A.

    1995-01-01

    Starch filled plastids termed amyloplasts, contained within columella cells of the root caps of higher plant roots, are believed to play a statolith-like role in the gravitropic response of roots. Plants having amyloplasts containing less starch exhibit a corresponding reduction in gravitropic response. We have observed enhanced ethylene production by sweet clover (Melilotus alba L.) seedlings grown in the altered gravity condition of a slow rotating clinostat, and have suggested that this is a stress response resulting from continuous gravistimulation rather than as a result of the simulation of a microgravity condition. If so, we expect that plants deficient in starch accumulation in amyloplasts may produce less stress ethylene when grown on a clinostat. Therefore, we have grown Arabidopsis thaliana in the small, closed environment of the Fluid Processing Apparatus (FPA). In this preliminary report we compare stationary plants with clinorotated and those grown in microgravity aboard Discovery during the STS-63 flight in February 1995. In addition to wildtype, two mutants deficient in starch biosynthesis, mutants TC7 and TL25, which are, respectively, deficient in the activity of amyloplast phosphoglucomutase and ADP-glucose pyrophosphorylase, were grown for three days before being fixed within the FPA. Gas samples were aspirated from the growth chambers and carbon dioxide and ethylene concentations were measured using a gas chromatograph. The fixed tissue is currently undergoing further morphologic and microscopic characterization.

  1. Sensory and metabolic profiles of "Fuji" apples (Malus domestica Borkh.) grown without synthetic agrochemicals: the role of ethylene production.

    PubMed

    Tanaka, Fukuyo; Miyazawa, Toshio; Okazaki, Keiki; Tatsuki, Miho; Ito, Tsutae

    2015-01-01

    Flavors of "Fuji" apple cultivated with or without synthetic agrochemicals were compared using quantitative descriptive analyses (QDA) and metabolite profiling for 3 seasons. Experimental plots included conventional crops (with agrochemicals) and organic crops (without agrochemicals) at our institute and organic and conventional farms. Additionally, mass market samples were analyzed. Organic apples were weak in sweetness and floral characteristics and had enhanced green and sour flavors. Most esters and sugars were present in lower concentrations in organic than in conventional apples. Close relation of principal component 1 of QDA and metabolite profiles, to ethylene production suggested that ethylene is considerably involved in flavor synthesis. Reduced ethylene associated with immaturity accounted for insufficient flavor synthesis and weak aroma and flavor attributes of organic apples. Furthermore, organic apples from the farm were more flavorsome than those from the institute in 2012, suggesting possible recovery of ethylene production after a long organic cultivation period. PMID:26140475

  2. Spikelet-specific variation in ethylene production and constitutive expression of ethylene receptors and signal transducers during grain filling of compact- and lax-panicle rice (Oryza sativa) cultivars.

    PubMed

    Sekhar, Sudhanshu; Panda, Binay B; Mohapatra, Trupti; Das, Kaushik; Shaw, Birendra P; Kariali, Ekamber; Mohapatra, Pravat K

    2015-05-01

    Grain yields in modern super rice cultivars do not always meet the expectations because many spikelets are located on secondary branches in closely packed homogeneous distribution in these plants, and they do not fill properly. The factors limiting grain filling of such spikelets, especially in the lower panicle branches, are elusive. Two long-duration rice cultivars differing in panicle density, Mahalaxmi (compact) and Upahar (lax), were cultivated in an open field plot. Grain filling, ethylene production and constitutive expression of ethylene receptors and ethylene signal transducers in apical and basal spikelets of the panicle were compared during the early post-anthesis stage, which is the most critical period for grain development. In another experiment, a similar assessment was made for the medium-duration cultivars compact-panicle OR-1918 and lax-panicle Lalat. Grain weight of the apical spikelets was always higher than that of the basal spikelets. This gradient of grain weight was wide in the compact-panicle cultivars and narrow in the lax-panicle cultivars. Compared to apical spikelets, the basal spikelets produced more ethylene at anthesis and retained the capacity for post-anthesis expression of ethylene receptors and ethylene signal transducers longer. High ethylene production enhanced the expression of the RSR1 gene, but reduced expression of the GBSS1 gene. Ethylene inhibited the partitioning of assimilates of developing grains resulting in low starch biosynthesis and high accumulation of soluble carbohydrates. It is concluded that an increase in grain/spikelet density in rice panicles reduces apical dominance to the detriment of grain filling by production of ethylene and/or enhanced perception of the ethylene signal. Ethylene could be a second messenger for apical dominance in grain filling. The manipulation of the ethylene signal would possibly improve rice grain yield. PMID:25817414

  3. Facile synthesis of porous worm-like Pd nanotubes with high electrocatalytic activity and stability towards ethylene glycol oxidation

    NASA Astrophysics Data System (ADS)

    Feng, Jiu-Ju; Zhou, Dan-Ling; Xi, Huan-Xiang; Chen, Jian-Rong; Wang, Ai-Jun

    2013-07-01

    A facile method was developed for large-scale preparation of porous worm-like Pd nanotubes based on the reduction of PdO nanotubes, which were obtained by calcining the complex precipitate of [Pd(dimethylglyoxime)2]n. The Pd catalyst showed excellent electrocatalytic activity and stability towards ethylene glycol oxidation.A facile method was developed for large-scale preparation of porous worm-like Pd nanotubes based on the reduction of PdO nanotubes, which were obtained by calcining the complex precipitate of [Pd(dimethylglyoxime)2]n. The Pd catalyst showed excellent electrocatalytic activity and stability towards ethylene glycol oxidation. Electronic supplementary information (ESI) available: Experimental section and Fig. S1-S7. See DOI: 10.1039/c3nr01578e

  4. Poly(ethylene oxide) Functionalized Graphene Nanoribbons with Excellent Solution Processability.

    PubMed

    Huang, Yinjuan; Mai, Yiyong; Beser, Uliana; Teyssandier, Joan; Velpula, Gangamallaiah; van Gorp, Hans; Straasø, Lasse Arnt; Hansen, Michael Ryan; Rizzo, Daniele; Casiraghi, Cinzia; Yang, Rong; Zhang, Guangyu; Wu, Dongqing; Zhang, Fan; Yan, Deyue; De Feyter, Steven; Müllen, Klaus; Feng, Xinliang

    2016-08-17

    Structurally well-defined graphene nanoribbons (GNRs) have attracted great interest as next-generation semiconductor materials. The functionalization of GNRs with polymeric side chains, which can widely broaden GNR-related studies on physiochemical properties and potential applications, has remained unexplored. Here, we demonstrate the bottom-up solution synthesis of defect-free GNRs grafted with flexible poly(ethylene oxide) (PEO) chains. The GNR backbones possess an armchair edge structure with a width of 1.0-1.7 nm and mean lengths of 15-60 nm, enabling near-infrared absorption and a low bandgap of 1.3 eV. Remarkably, the PEO grafting renders the GNRs superb dispersibility in common organic solvents, with a record concentration of ∼1 mg mL(-1) (for GNR backbone) that is much higher than that (<0.01 mg mL(-1)) of reported GNRs. Moreover, the PEO-functionalized GNRs can be readily dispersed in water, accompanying with supramolecular helical nanowire formation. Scanning probe microscopy reveals raft-like self-assembled monolayers of uniform GNRs on graphite substrates. Thin-film-based field-effect transistors (FETs) of the GNRs exhibit a high carrier mobility of ∼0.3 cm(2) V(-1) s(-1), manifesting promising application of the polymer-functionalized GNRs in electronic devices. PMID:27463961

  5. Rheology and pressurised gyration of starch and starch-loaded poly(ethylene oxide).

    PubMed

    Mahalingam, S; Ren, G G; Edirisinghe, M J

    2014-12-19

    This work investigates the rheology and spinning of starch and starch-loaded poly(ethylene oxide) (PEO) by pressurised gyration in order to prepare nanofibres. The spinning dope's rheological properties played a crucial role in fibre formation. Newtonian behaviour is observed in 1-20 wt% starch suspensions and non-Newtonian behaviour is found in all the PEO-starch mixtures. Pressurised gyration of the starch suspensions produced beads only but PEO-starch mixtures generated fibres. The fibre diameter of the PEO-starch samples is shown to be a function of polymer concentration and rotating speed of the gyration system. Fibre formation can only be facilitated below a certain working pressure. The concentration of starch in the PEO-starch mixtures is crucial in defining whether beaded or continuous fibres were generated and this is related to the composition of the spinning dope. FT-IR, XRD and microscopy studies indicated very good miscibility of starch and PEO in the nanofibres. The storage modulus of the PEO-starch were also studied as a function of temperature (30-150°C) and showed interesting results but it was not possible to deduce general trends valid for the entire temperature range. PMID:25263892

  6. Preventing corona effects: multiphosphonic acid poly(ethylene glycol) copolymers for stable stealth iron oxide nanoparticles.

    PubMed

    Torrisi, V; Graillot, A; Vitorazi, L; Crouzet, Q; Marletta, G; Loubat, C; Berret, J-F

    2014-08-11

    When dispersed in biological fluids, engineered nanoparticles are selectively coated with proteins, resulting in the formation of a protein corona. It is suggested that the protein corona is critical in regulating the conditions of entry into the cytoplasm of living cells. Recent reports describe this phenomenon as ubiquitous and independent of the nature of the particle. For nanomedicine applications, however, there is a need to design advanced and cost-effective coatings that are resistant to protein adsorption and that increase the biodistribution in vivo. In this study, phosphonic acid poly(ethylene glycol) copolymers were synthesized and used to coat iron oxide particles. The copolymer composition was optimized to provide simple and scalable protocols as well as long-term stability in culture media. It is shown that polymers with multiple phosphonic acid functionalities and PEG chains outperform other types of coating, including ligands, polyelectrolytes, and carboxylic acid functionalized PEG. PEGylated particles exhibit moreover exceptional low cellular uptake, of the order of 100 femtograms of iron per cell. The present approach demonstrates that the surface chemistry of engineered particles is a key parameter in the interactions with cells. It also opens up new avenues for the efficient functionalization of inorganic surfaces. PMID:25046557

  7. Comprehensive Phase Behavior of Poly(isoprene-b-styrene-b-ethylene oxide) Triblock Copolymers

    SciTech Connect

    Chatterjee, Joon; Jain, Sumeet; Bates, Frank S.

    2010-03-05

    The phase behavior of 44 poly(isoprene-b-styrene-b-ethylene oxide) (ISO) linear triblock copolymer melts was investigated at weak to intermediate segregation strengths and spanning a comprehensive range of compositions. Phases were characterized by a combination of experimental techniques, including small-angle X-ray scattering, dynamic mechanical spectroscopy, transmission electron microscopy, and birefringence measurements. Combined with our previous results, six different stable ordered state symmetries have been identified: lamellae (LAM), Fddd orthorhombic network (O{sup 70}), double gyroid (Q{sup 230}), alternating gyroid (Q{sup 214}), hexagonal (HEX), and body-centered cubic (BCC). The phase map of ISO specimens was found to be somewhat asymmetric around the f{sub I} = f{sub O} isopleth. This work provides a guide for theoretical studies and gives insight into the intricate effects of various parameters on the self-assembly of ABC triblock copolymers. Experimental SAXS data evaluated with a simple scattering intensity model show that local mixing varies continuously across the phase map between states of two- and three-domain segregation.

  8. Platelet adhesion and cellular interaction with poly(ethylene oxide) immobilized onto silicone rubber membrane surfaces.

    PubMed

    Hsiue, G H; Lee, S D; Chang, P C

    1996-01-01

    Cellular interaction and platelet adsorption were investigated on poly(ethylene oxide) (PEO) immobilized silicone rubber membrane (SR) which has polyacrylic acid grafts on the surfaces. Polyacrylic acid (PAA) had been introduced to the SR surface after Ar plasma treatment of SR surfaces to introduce peroxide groups. Surface characterizations were made using ATR-FTIR, ESCA, SEM, and contact angle measurements. Experimental results obtained by ESCA high resolution curve fitting spectra indicated that the amount of bisamino PEO of different molecular weights immobilized onto SR surfaces were similar, which showed that the influence of the length of molecular chains (-C-C-O-) on the reactivity of terminal amino group is negligible. The wettability of modified SR surfaces increased with an increase in PEO molecular weight. Biological studies such as corneal epithelial cell culture and blood platelet adhesion were performed to understand the biocompatibility of modified SR surfaces. Biological studies using corneal epithelial cells showed that cell migration, attachment and proliferation onto PEO-20000 immobilized SR surface were suppressed, whereas these biological activities on PEO-600 were enhanced. Another study on platelet adhesion revealed that many platelets attached to PEO-600 immobilized SR, while platelet deposition was rarely observed on SR grafted with PEO-3350. The effects of different PEO molecular chains on biological response were discussed. PMID:8836831

  9. Simultaneous Surface Modification and Chemical Reduction of Graphene Oxide Using Ethylene Diamine.

    PubMed

    Pan, Hui; Zhang, Yudong; Wang, Xiaodong; Yu, Laigui; Zhang, Zhijun

    2016-03-01

    We report a simple and facile method of reducing and modifying graphene oxide (GO) simultaneously using ethylene diamine (ED). The ED-modified and reduced GO (denoted as E-rGO) as well as the GO reduced by hydrazine hydrate (denoted as H-rGO) were characterized by Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), Raman spectra, Thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM). It was found that as-prepared E-rGO exhibited good dispersibility in water and water-borne polyurethane (denoted as WPU) matrix and improve greatly the mechanical properties of WPU matrix. Moreover, E-rGO showed a high electric conductivity close to that of H-rGO after ultrasonic treatment for 12 h, which indicated that ED had the desired reducibility. The present approach could help to broaden the application field of graphene nanosheets and provide a new opportunity for developing high performance graphene/polymer-matrix composites. PMID:27455669

  10. Self-organization of poly(ethylene oxide) on the surface of aqueous salt solutions.

    PubMed

    Fuchs, Christian; Hussain, Hazrat; Amado, Elkin; Busse, Karsten; Kressler, Joerg

    2015-01-01

    It is demonstrated that stable Langmuir films of poly(ethylene oxide) (PEO) can be formed up to surface pressures of 30 mN m(-1) when potassium carbonate K2CO3 is added to the aqueous subphase. Generally, PEO homopolymer cannot stay on the water surface at a surface pressure ≥10 mN m(-1) due to its high water solubility. To prepare stable monolayer films, PEO can be modified with hydrophobic moieties. However, by exploiting the salting out effect by adding certain salts (K2CO3 or MgSO4) into the aqueous subphase, not only very stable films but also unusual self-organization can be achieved by the PEO homopolymer on the surface of the aqueous solution. Thus, a series of OH-terminated PEOs is found to form a stable monolayer at K2CO3 concentrations of 2 M and above in the aqueous subphase, and the stability of the film increases with an increase in K2CO3 concentration. Hysteresis experiments are also carried out. During the phase transition induced by progressive compression, self-organization into well-defined domains with sizes in the micrometer range are observed, and with further compression and holding of the film for 30 min and above the microdomains transform into a crystalline morphology as visualized by Brewster angle microscopy. PMID:25269665

  11. Photopolymerization-induced crystallization and phase separation in poly(ethylene oxide)/triacrylate blends

    SciTech Connect

    Park, Soo Jeoung; Kyu, Thein

    2008-12-28

    The present article describes experimental and theoretical investigations of miscibility and crystallization behavior of blends of poly(ethylene oxide) (PEO) and triacrylate monomer (TA) using differential scanning calorimetry and optical microscopy. The PEO/TA blends manifested a single T{sub g} varying systematically with composition suggestive of a miscible character in their amorphous states. Moreover, there occurs melting point depression of PEO crystals with increasing TA. A phase diagram was subsequently established that exhibited a solid+liquid coexistence region bound by the liquidus and solidus lines, followed by an upper critical solution temperature (UCST) at a lower temperature. The emerging phase morphology was investigated to verify the coexistence regions. Upon photopolymerization in the isotropic melt above the melting point depression curve, both the UCST and the melting temperatures move upward and eventually surpass the reaction temperature, resulting in phase separation as well as crystallization of PEO driven by the changing supercooling, i.e., the thermodynamic driving force. Of particular interest is the interplay between photopolymerization-induced phase separation and crystallization, which eventually determines the final phase morphology of the PEO/TA blend such as crystalline lamellae, sheaf, or spherulites in isotropic liquid, phase separated domains, and viscous fingering liquids.

  12. Solid dispersion of acetaminophen and poly(ethylene oxide) prepared by hot-melt mixing.

    PubMed

    Yang, Min; Wang, Peng; Huang, Chien-Yueh; Ku, M Sherry; Liu, Huiju; Gogos, Costas

    2010-08-16

    In this study, a model drug, acetaminophen (APAP), was melt mixed with poly(ethylene oxide) (PEO) using a Brabender mixer. APAP was found to recrystallize upon cooling to room temperature for all the drug loadings investigated. Higher drug loading leads to faster recrystallization rate. However, the morphology of the recrystallized drug crystals is identical in samples with different drug loadings and does not change with the storage time. To adjust the drug's dissolution rate, nanoclay Cloisite 15A and 30B were added into the binary mixture. The presence of either of the nanoclay dramatically accelerates the drug's recrystallization rate and slows down the drug's releasing rate. The drop of the releasing rate is mainly due to the decrease of wettability, as supported by the contact angle data. Data analysis of the dissolution results suggests that the addition of nanoclays changes the drug's release mechanism from erosion dominant to diffusion dominant. This study suggests that nanoclays may be utilized to tailor the drug's releasing rate and to improve the dosage form's stability by dramatically shortening the lengthy recrystallization process. PMID:20435110

  13. Mechanical strength of cortical allografts with gamma radiation versus ethylene oxide sterilization.

    PubMed

    Zhou, Zongke; Qin, Tingwu; Yang, Jing; Shen, Bin; Kang, Pengde; Peil, Fuxing

    2011-10-01

    We investigated the effects of gamma irradiation versus ethylene oxide (ETO) sterilization on the mechanical strength of cortical bone grafts. Tibias were collected from cadavers of mature goats. Sixty test specimens were randomized into four groups: fresh (no processing), frozen (freezing at -70 degrees C), gamma-irradiated, and ETO-sterilized specimens. Torsion, three-point bending, and compression testing were separately performed with a material testing machine. Parameters studied included maximum stress, strain, deflection, extension, load, shear modulus, and E-modulus. Compared with findings for the fresh specimens, findings were as follows for gamma-irradiated specimens: maximal shear modulus, reduced by 48%; shear stress, by 55%; deflection, by 71%; bending stress, by 51%; bending strain, by 74%; extension, by 60%; and compression strain, by 50%. However, there were no reductions in those parameters for the frozen specimens or the ETO-sterilized specimens. These findings confirm that shear, bending, and compression strength of cortical allografts are weakened by gamma irradiation at room temperature. To maintain optimum mechanical properties, ETO sterilization of allografts is better than gamma sterilization, especially for cortical bone, because it is usually used in load-bearing settings. PMID:22187845

  14. Encapsulation of T4 bacteriophage in electrospun poly(ethylene oxide)/cellulose diacetate fibers.

    PubMed

    Korehei, Reza; Kadla, John F

    2014-01-16

    Phage therapy is a potentially beneficial approach to food preservation and storage. Sustained delivery of bacteriophage can prevent bacterial growth on contaminated food surfaces. Using coaxial electrospinning bacteriophage can be encapsulated in electrospun fibers with high viability. The resulting bio-based electrospun fibers may have potential as a food packaging material. In the present work, T4 bacteriophage (T4 phage) was incorporated into core/shell electrospun fibers made from poly(ethylene oxide) (PEO), cellulose diacetate (CDA), and their blends. Fibers prepared using PEO as the shell polymer showed an immediate burst release of T4 phage upon submersion in buffer. The blending of CDA with PEO significantly decreased the rate of phage release, with no released T4 phage being detected from the solely CDA fibers. Increasing the PEO molecular weight increased the electrospun fiber diameter and viscosity of the releasing medium, which resulted in a relatively slower T4 phage release profile. SEM analyses of the electrospun fiber morphologies were in good agreement with the T4 phage release profiles. Depending on the PEO/CDA ratio, the post-release electrospun fiber morphologies varied from discontinuous fibers to minimally swollen fibers. From these results it is suggested that the T4 phage release mechanism is through solvent activation/polymer dissolution in the case of the PEO fibers and/or by diffusion control from the PEO/CDA blend fibers. PMID:24188849

  15. Field evaluation of direct-reading continuous ethylene oxide monitors. Final report

    SciTech Connect

    Hossain, M.A.; Carpenter, D.R.

    1989-05-01

    The Wilford Hall USAF Medical Center Central Processing Section (WHMC/SGLP) uses ethylene oxide (EtO) as a primary sterilizing agent. Because of their concern about the health effects of EtO, SGLP has searched for a continuous-monitoring EtO system. In their search, they found two units (AMSCO's Envirogard III and Baseline Industries, Inc.'s Model 5500 Gas Analyzer). The objective of this evaluation was to conduct a field study to compare the performances of the two direct-reading continuous EtO monitors against the Occupational Safety and Health Administration's (OSHA) acceptable charcoal-tube sampling method. In addition, the 3M EtO passive monitor sampling method was compared with the charcoal-tube method and direct-reading instrumental method as well. Neither the Baseline Industries, Inc. nor the AMSCO continuous monitors corresponded to OSHA acceptable charcoal tube method of air sampling. Both instruments reported EtO concentrations much higher than those detected by the charcoal tubes. There is no way of knowing which method, the direct-reading continuous monitor or the charcoal tube/passive monitor, is more correct. However, the OSHA standard for EtO is based on measuring EtO by the charcoal tube method.

  16. Lyotropic Phase Behavior of Polybutadiene-Poly(ethylene oxide) Diblock Copolymers in Ionic Liquids

    SciTech Connect

    Simone, Peter M.; Lodge, Timothy P.

    2008-08-26

    The lyotropic phase behavior of three poly(1,2-butadiene-b-ethylene oxide) diblock copolymers (PB-PEO) with different monomer volume fractions has been studied in two different ionic liquids, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMI][TFSI]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMI][PF{sub 6}]), across the complete concentration range. The ordered microstructures present in the solutions were characterized via small-angle X-ray scattering (SAXS). The phase diagrams for the PB-PEO/ionic liquid solutions include regions corresponding to the classical copolymer microstructures: body-centered-cubic lattices of spheres, hexagonally ordered cylinders, and lamellae. Additionally, the phase diagrams also include wide regions of coexisting microstructures and regions apparently corresponding to a disordered network microstructure. The phase behavior of the PB-PEO copolymers in both ionic liquids was comparable to their previously reported aqueous solution behavior. The temperature dependence of the phase diagrams was very modest, indicative of a highly segregated system. The level of solvent selectivity was also investigated via cryogenic transmission electron microscopy (cryo-TEM) on dilute solutions. On the basis of the morphology of the dilute solution copolymer aggregate structures in the ionic liquid solvents, and on the structural length scales of the concentrated solutions, it was concluded that for PB-PEO [BMI][PF{sub 6}] behaves as a more selective solvent than [EMI][TFSI].

  17. Curing kinetics and morphology of a nanovesicular epoxy/stearyl-block-poly(ethylene oxide) surfactant system.

    PubMed

    Bogaerts, K; Lavrenova, A; Spoelstra, A B; Boyard, N; Goderis, B

    2015-08-21

    Brittle epoxy based thermosets can be made tougher by introducing structural inhomogeneities at the micro- or nanoscale. In that respect, nano vesicles and worm-like micelles from self-assembling blockcopolymers have been shown to be very effective. This paper describes the curing kinetics and morphology of an epoxy composed of diglycidyl ether of bisphenol A (DGEBA) and 4,4'-methylenedianiline (MDA), modified by 20% of the surfactant stearyl-block-poly(ethylene oxide). Time resolved, synchrotron small-angle X-ray scattering demonstrates that at any time during the epoxy curing process, the surfactant predominantly adopts a bilayer vesicular nano-morphology. Transmission electron microscopy on fully cured systems reveals the coexistence of spherical and worm-like micelles. Differential scanning calorimetry experiments prove that the presence of surfactant reduces the epoxy curing rate but that ultimately full curing is accomplished. The material glass transition temperature falls below that of the pure resin due to plasticization. It is suggested that favorable secondary interactions between the PEO segments and the epoxy resin are responsible for the observed phenomena. PMID:26144526

  18. Structure and drug release in a crosslinked poly(ethylene oxide) hydrogel.

    PubMed

    Shekunov, Boris Y; Chattopadhyay, Pratibhash; Tong, Henry H Y; Chow, Albert H L; Grossmann, J Günter

    2007-05-01

    Hydrogels are a continuously expanding class of pharmaceutical polymers designed for sustained or controlled drug release. The structure and intermolecular interactions in such systems define their macroscopic properties. The aim of this study was to investigate the mechanism of swelling, drug impregnation, and drug release from poly(ethylene oxide) (PEO) gel crosslinked by urethane bonds. A combination of SAXS/WAXS/SANS techniques enabled us to determine the phase transition between lamellar and extended gel network, and to apply different descriptions of crystallinity, based on lamellar and crystal lattice structures. It is shown that even low (1-7% w/w) loading of model drugs acetaminophen and caffeine, produced significant disorder in the polymer matrix. This effect was particularly pronounced for acetaminophen due to its specific ability to form complexes with PEO. The drug-release profiles were analyzed using a general cubic equation, proposed for this work, which allowed us to determine the gel hydration velocity. The results indicate that the release profiles correlate inversely with the polymer crystallinity. PMID:17455363

  19. Interfacial Effect on Confined Crystallization of Poly(ethylene oxide)/Silica Composites

    NASA Astrophysics Data System (ADS)

    Su, Yunlan; Zhao, Weiwei; Gao, Xia; Xu, Jianjun; Wang, Dujin

    The impact of nanoconfinement introduced by nanoparticles on polymer crystallization has attracted extensive attention because it plays the decisive role in the ultimate properties of polymer nanocomposites. In this study, interfacial and spatial confinement effects of silica (SiO2) nanoparticles on the crystallization behaviors of poly(ethylene oxide) (PEO)/SiO2 composites were systematically investigated by changing the size and concentration of SiO2 in PEO matrix. The composites with high silica loadings exhibit two crystallization peaks of PEO as determined by differential scanning calorimetry (DSC). The first peak at 7-43 °C is related to the bulk PEO, while the second peak at -20 to -30 °C is attributed to the restricted PEO segments. Three-layer (amorphous, interfacial and bulk) model is proposed to interpret the confined crystallization of PEO/SiO2 composites, which is supported by the results of thermogravimetric analysis (TGA) and solid-state 1H nuclear magnetic resonance (NMR). In amorphous layer, most PEO segments are directly adsorbed on SiO2 surface via hydrogen bonding. The interfacial PEO layer, which is nonuniform, is composed of crystallizable loops and tails extending from amorphous layer. National Natural Science Foundation of China (NSFC) under Contract 21274156.

  20. Li ion conductors based on laponite/poly(ethylene oxide) composites

    SciTech Connect

    Doeff, M.M.; Reed, J.S.

    1997-11-01

    Synthesis and characterization of single ion conducting poly(ethylene oxide) (PEO)/Li-laponite nanocomposites are reported. The amount of PEO that can be intercalated into laponite, a synthetic hectorite with high surface area, ranges from about 0.7g/g Li-laponite when the polymer average molecular weight is 1,000 or above, to about 1 g/g for oligomers of average molecular weight 500. The interlayer spacing increases from about 10 {angstrom} in the dry clay to 20--24 {angstrom} in the nanocomposites, depending upon polymer molecular weight, and the average particle size increases proportionally, but is still in the sub-micron range. AC impedance measurements on the clear, slightly brittle, self-supporting films indicate that the nanocomposite conductivity is greatly enhanced over that of the dry clay. A maximum of about 10{sup {minus}6} S/cm at 80 C is obtained for materials containing a slight excess of polymer, and conductivities of nanocomposites containing PEO were generally higher than that of those containing oxymethylene linked polyethylene glycol (amorphous PEOs). Suggestions for further improving conductivity and mechanical properties of these novel materials are presented.

  1. Industry-wide studies report of an industrial hygiene of Kettering Medical Center, Kettering, Ohio. [Ethylene oxide

    SciTech Connect

    Ringenburg, V.L.; Morelli-Schroth, P.; Elliott, L.J.

    1986-05-01

    Environmental and breathing-zone samples were analyzed for ethylene oxide in the respiratory therapy area of Kettering Medical Center, Kettering, Ohio in August, 1985. Work practices and engineering controls were observed. Engineering controls included local exhaust ventilation over sterilizer doors and the pressure relief valve and floor drain, and dedicated exhaust ventilation of the sterilizers and aerators. Effective work practices included wearing cotton gloves when unloading sterilizers and pulling instead of pushing carts containing sterilized items.

  2. Comparative sterilization effectiveness of plasma in O2-H2O2 mixtures and ethylene oxide treatment.

    PubMed

    Silva, J M F; Moreira, A J; Oliveira, D C; Bonato, C B; Mansano, R D; Pinto, T J A

    2007-01-01

    We investigated the influence of variable parameters of plasma sterilization and compared its effectiveness with that of ethylene oxide using a reactive ion etching plasma reactor at 13.56 MHz. Gases tested were pure oxygen and oxygen-hydrogen peroxide mixtures in 190/10, 180/20, and 160/40 sccm ratios with constant gas flow at 200 sccm, pressure at 0.100 torr, radio-frequency power at 25 W, 50 W, 100 W, and 150 W, and temperature below 60 degrees C. Ethylene oxide sterilization was performed using 450 mg/L at 55 degrees C, 60% humidity, and -0.65 and 0.60 kgf/cm2 pressure. The biological indicator was Bacillus atrophaeus ATCC 9372, with exposure times of 3 to 120 min. Observed D values were 215.91, 55.55, 9.19, and 2.98 min for pure oxygen plasma at 25 W, 50 W, 100 W, and 150 W, respectively. Oxygen-hydrogen peroxide plasma produced D values of 6.41 min (190/10), 6.47 min (180/20), and 4.02 min (160/40) at 100 W and 1.47 min (190/10), 3.11 min (180/20), and 1.94 min (160/40) at 150 W. Ethylene oxide processes resulted in a D value of 2.86 min. Scanning electron microscopy analyses showed damage to the spore cortex. PMID:17722487

  3. High-temperature catalytic oxidative conversion of propane to propylene and ethylene involving coupling of exothermic and endothermic reactions

    SciTech Connect

    Choudhary, V.R.; Rane, V.H.; Rajput, A.M.

    2000-04-01

    Coupling of the exothermic catalytic oxidative conversion and endothermic thermal cracking (noncatalytic) reactions of propane to propylene and ethylene over the SrO/La{sub 2}O{sub 3}/SA5205 catalyst in the presence of steam and limited oxygen was investigated at different process conditions (temperature, 700--850 C; C{sub 3}H{sub 8}/O{sub 2} ratio in feed, 2.0--8.0; H{sub 2}O/C{sub 3}H{sub 8} ratio, 0.5--2.5; space velocity, 2,000--15,000 cm{sup 3}/g h). In the presence of steam and limited O{sub 2}, the endothermic thermal cracking and exothermic oxidative conversion reactions occur simultaneously and there is no coke formation on the catalyst. Because of the direct coupling of exothermic and endothermic reactions, this process occurs in a most energy efficient and safe manner. The propane conversion, selectivity for propylene, and net heat of reaction ({Delta}H{sub r}) in the process are strongly influenced by the temperature and concentration of O{sub 2} relative to the propane in the feed. The C{sub 3}H{sub 6}/C{sub 2}H{sub 4} product ratio is also strongly influenced by the temperature, C{sub 3}H{sub 8}/O{sub 2} feed ratio, and space velocity. The net heat of reaction can be controlled by manipulating the reaction temperature and C{sub 3}H{sub 8}/O{sub 2} ratio in the feed; the process exothermicity is reduced drastically with increasing the temperature and/or C{sub 3}H{sub 8}/O{sub 2} feed ratio.

  4. Dimethyl Sulfide-Dimethyl Ether and Ethylene Oxide-Ethylene Sulfide Complexes Investigated by Fourier Transform Microwave Spectroscopy and AB Initio Calculation

    NASA Astrophysics Data System (ADS)

    Kawashima, Yoshiyuki; Tatamitani, Yoshio; Mase, Takayuki; Hirota, Eizi

    2015-06-01

    The ground-state rotational spectra of the dimethyl sulfide-dimethyl ether (DMS-DME) and the ethylene oxide and ethylene sulfide (EO-ES) complexes were observed by Fourier transform microwave spectroscopy, and a-type and c-type transitions were assigned for the normal, 34S, and three 13C species of the DMS-DME and a-type and b-type rotational transitions for the normal, 34S, and two 13C species of the EO-ES. The observed transitions were analyzed by using an S-reduced asymmetric-top rotational Hamiltonian. The rotational parameters thus derived for the DMS-DME were found consistent with a structure of Cs symmetry with the DMS bound to the DME by two C-H(DMS)---O and one S---H-C(DME) hydrogen bonds. The barrier height V3 to internal rotation of the "free" methyl group in the DME was determined to be 915.4 (23) wn, which is smaller than that of the DME monomer, 951.72 (70) wn, and larger than that of the DME dimer, 785.4 (52) wn. For the EO-ES complex the observed data were interpreted in the terms of an antiparallel Cs geometry with the EO bound to the ES by two C-H(ES)---O and two S---H-C(EO) hydrogen bonds. We have applied a natural bond orbital (NBO) analysis to the DMS-DME and EO-ES to calculate the stabilization energy CT (= ΔEσσ*), which were closely correlated with the binding energy EB, as found for other related complexes. Y. Niide and M. Hayashi, J. Mol. Spectrosc. 220, 65-79 (2003). Y. Tatamitani, B. Liu, J. Shimada, T. Ogata, P. Ottaviani, A. Maris, W. Caminati, and J. L. Alonso, J. Am. Chem. Soc. 124, 2739-2743 (2002).

  5. Repressed ethylene production in the gynoecium of long-lasting flowers of the carnation 'White Candle': role of the gynoecium in carnation flower senescence.

    PubMed

    Nukui, Hideki; Kudo, Sakiko; Yamashita, Atsushi; Satoh, Shigeru

    2004-03-01

    Ethylene production and expression of ethylene biosynthetic genes was investigated in senescing flowers of carnation (Dianthus caryophyllus L.) cultivars 'White Candle (WC)' and 'Light Pink Barbara (LPB)', with long and short vase-lives, respectively. Ethylene production from the gynoecium and petals of senescing 'WC' flowers was below the limit of detection, in agreement with the repressed ethylene production from the whole flowers. However, exogenous ethylene treatment caused the accumulation of transcripts for DC-ACS1 and DC-ACO1 genes in both the gynoecium and petals, resulting in ethylene production from the flowers. Moreover, application of ABA or IAA, which are known to exhibit their action through the induction of ethylene synthesis in the gynoecium, to 'WC' flowers from their cut stem-end induced ethylene production and wilting in the flowers. These findings suggested that, in 'WC' flowers the mechanism of ethylene biosynthesis, i.e. the induction of expression of genes for ethylene biosynthesis and the action of resulting enzymes, was not defective, but that its function was repressed during natural senescence. Transcripts of DC-ACO1, DC-ACS3, and DC-ACS1 were present in the gynoecium of senescing 'LPB' flowers. In the gynoecium of senescing 'WC' flowers, however, the DC-ACO1 transcript was present, but the DC-ACS1 transcript was absent and the DC-ACS3 transcript was detected only in a small amount; the latter two were associated with the low rate of ethylene production in the gynoecium of 'WC' flowers. These findings indicated that the repressed ethylene production in 'WC' flowers during natural senescence is caused by the repressed ethylene production in the gynoecium, giving further support for the role of the gynoecium in regulating petal senescence in carnation flowers. PMID:14966220

  6. Pollination increases ethylene production in Lilium hybrida cv. Brindisi flowers but does not affect the time to tepal senescence or tepal abscission.

    PubMed

    Pacifici, Silvia; Prisa, Domenico; Burchi, Gianluca; van Doorn, Wouter G

    2014-09-01

    In many species, pollination induces a rapid increase in ethylene production, which induces early petal senescence, petal abscission, or flower closure. Cross-pollination in Lilium hybrida cv. Brindisi resulted in a small increase in flower ethylene production. In intact plants and in isolated flowers, pollination had no effect on the time to tepal senescence or tepal abscission. When applied to closed buds of unpollinated flowers, exogenous ethylene slightly hastened the time to tepal senescence and abscission. However, exogenous ethylene had no effect when the flowers had just opened, i.e. at the time of pollination. Experiments with silver thiosulphate, which blocks the ethylene receptor, indicated that endogenous ethylene had a slight effect on the regulation of tepal senescence and tepal abscission, although only at the time the tepals were still inside buds and not in open flowers. Low ethylene-sensitivity after anthesis therefore explains why pollination had no effect on the processes studied. PMID:25462085

  7. Ethylene Oxide and Hydrogen Peroxide Gas Plasma Sterilization: Precautionary Practices in U.S. Hospitals

    PubMed Central

    Boiano, James M.; Steege, Andrea L.

    2015-01-01

    Objective Evaluate precautionary practices and extent of use of ethylene oxide (EtO) and hydrogen peroxide gas plasma (HPGP) sterilization systems, including use of single chamber EtO units. Design Modular, web-based survey. Participants Members of professional practice organizations who reported using EtO or HPGP in the past week to sterilize medical instruments and supplies. Participating organizations invited members via email which included a hyperlink to the survey. Methods Descriptive analyses were conducted including simple frequencies and prevalences. Results A total of 428 respondents completed the module on chemical sterilants. Because most respondents worked in hospitals (87%, n=373) analysis focused on these workers. Most used HPGP sterilizers (84%, n=373), 38% used EtO sterilizers, with 22% using both. Nearly all respondents using EtO operated single chamber units (94%, n=120); most of them reported that the units employed single use cartridges (83%, n=115). Examples of where engineering and administrative controls were lacking for EtO include: operational local exhaust ventilation (7%; n=114); continuous air monitoring (6%; n=113); safe handling training (6%; n=142); and standard operating procedures (4%; n=142). Examples of practices which may increase HPGP exposure risk included lack of standard operating procedures (9%; n=311) and safe handling training (8%; n=312). Conclusions Use of precautionary practices was good but not universal. EtO use appears to have diminished in favor of HPGP which affords higher throughput and minimal regulatory constraints. Separate EtO sterilization and aeration units were still being used nearly one year after U.S. EPA prohibited their use. PMID:26594097

  8. Polymer chain organization in tensile-stretched poly(ethylene oxide)-based polymer electrolytes.

    PubMed

    Burba, Christopher M; Woods, Lauren; Millar, Sarah Y; Pallie, Jonathan

    2011-12-15

    Polymer chain orientation in tensile-stretched poly(ethylene oxide)-lithium trifluoromethanesulfonate polymer electrolytes are investigated with polarized infrared spectroscopy as a function of the degree of strain and salt composition (ether oxygen atom to lithium ion ratios of 20:1, 15:1, and 10:1). The 1359 and 1352 cm(-1) bands are used to probe the crystalline PEO and P(EO)(3)LiCF(3)SO(3) domains, respectively, allowing a direct comparison of chain orientation for the two phases. Two-dimensional correlation FT-IR spectroscopy indicates that the two crystalline domains align at the same rate as the polymer electrolytes are stretched. Quantitative measurements of polymer chain orientation obtained through dichroic infrared spectroscopy show that chain orientation predominantly occurs between strain values of 150% and 250%, regardless of salt composition investigated. There are few changes in chain orientation for either phase when the films are further elongated to a strain of 300%; however, the PEO domains are slightly more oriented at the high strain values. The spectroscopic data are consistent with stretching-induced melt-recrystallization of the unoriented crystalline domains in the solution-cast polymer films. Stretching the films pulls polymer chains from the crystalline domains, which subsequently recrystallize with the polymer helices parallel to the stretch direction. If lithium ion conduction in crystalline polymer electrolytes is viewed as consisting of two major components (facile intra-chain lithium ion conduction and slow helix-to-helix inter-grain hopping), then alignment of the polymer helices will affect the ion conduction pathways for these materials by reducing the number of inter-grain hops required to migrate through the polymer electrolyte. PMID:22184475

  9. Complement activation on poly(ethylene oxide)-like RFGD-deposited surfaces

    PubMed Central

    Szott, Luisa Mayorga; Stein, M. Jeanette; Ratner, Buddy D.; Horbett, Thomas A.

    2010-01-01

    Non-specific protein adsorption, particularly fibrinogen (Fg), is thought to be an initiating step in the foreign body response (FBR) to biomaterials by promoting phagocyte attachment. In previous studies, we therefore prepared radio frequency glow discharge (RFGD) polyethylene oxide (PEO)-like tetraglyme coatings (CH3O(CH2CH2O)4CH3) adsorbing less than 10 ng/cm2 Fg and showed that they had the expected low monocyte adhesion in vitro. However, when these were implanted in vivo, many adherent inflammatory cells and a fibrous capsule were found, suggesting the role of alternative proteins, such as activated complement proteins, in the FBR to these materials. We therefore investigated complement interactions with the tetraglyme surfaces. First, because of its well known role in complement C3 activation, we measured the hydroxyl group (-OH) content of tetraglyme, but found it to be very low. Second, we measured C3 adsorption to tetraglyme from plasma. Low amounts of C3 adsorbed on tetraglyme, though it displayed higher binding strength than the control surfaces. Finally, complement activation was determined by measuring C3a and SC5b-9 levels in serum after incubating with tetraglyme, as well as other surfaces that served as positive and negative controls, namely poly(vinyl alcohol) hydrogels, Silastic sheeting, and poly(ethylene glycol) self-assembled monolayers with different end groups. Despite displaying low hydroxyl group concentration, relatively high C3a and SC5b-9 levels were found in serum exposed to tetraglyme, similar to the values due to our positive control, PVA. Our results support the conclusion that complement activation by tetraglyme is a possible mechanism involved in the FBR to these biomaterials. PMID:21105163

  10. Pharmacokinetics of Polymersomes Composed of Poly(Butadiene-Ethylene Oxide); Healthy versus Tumor-Bearing Mice.

    PubMed

    Wang, G; de Kruijff, R M; Abou, D; Ramos, N; Mendes, E; Franken, L E; Wolterbeek, H T; Denkova, A G

    2016-02-01

    Vesicles composed of block copolymers (i.e., polymersomes) are one of the most versatile nano-carriers for medical purposes due to their tuneable physicochemical properties and the possibility to encapsulate simultaneously hydrophobic and hydrophilic substances, allowing, for instance, the combination of therapy and imaging. In cancer treatment, these vesicles need to remain long enough in the blood stream to be sufficiently taken up by tumors. Here, we have investigated the biodistribution and the pharmacokinetics of polymersomes, composed of poly(butadiene-b-ethylene oxide) having dimensions around 80 nm. The polymersomes have been radiolabeled with ¹¹¹In via the so-called active loading method achieving a loading efficiency of 92.9 ± 0.9% with radionuclide retention in mouse serum of more than 95% at 24 h. The optimized ¹¹¹In containing polymersomes have been intravenously administered in healthy and tumor bearing mice for pharmacokinetic determination using microSPECT (Single Photon Emission Computed Tomography). In healthy mice these polymersomes have been found to exhibit relatively long blood circulation (> 6 h), low liver uptake (6 ± 1.5%ID/g, 48 h p.i.) and elevated spleen uptake (188 ± 30%ID/g). The blood circulation in tumor bearing mice is dramatically reduced (< 1.5 h) most likely due to elevated splenic filtration, clearly indicating the importance of in vivo studies in diseased mice. Finally, the polymersomes have been injected subcutaneously in tumor bearing mice revealing retention of 77% in the mice, primarily accumulated at the site of injection, up to 48 hours after administration. PMID:27305765

  11. Use of multiparameter analysis to quantitate hematological damage from exposure to a chemical (ethylene oxide)

    SciTech Connect

    Popp, D.M.; Popp, R.A.; Lock, S.; Mann, R.C.; Hand, R.E. Jr.

    1986-01-01

    Mice exposed to 255 ppm ethylene oxide (EtO) for 6 h/d were removed for analysis after 1,2,4,8 and 14 d (sequential exposure) and 4,6,8 and 10 wk (5 d/wk). Prior to sacrifice, blood was removed from the orbital sinus for blood cell counts, hemoglobin determination, and hematocrit. A blood film was made for differential leukocyte counts. Bone marrow was flushed from femurs and tibias and counted, and aliquots were used for stem-cell assay (CFU-S) or flow cytometry (FCM) analysis. One aliquot of marrow was stained with propidium iodide for cell-cycle analysis and another was reacted with fluorescein-conjugated monoclonal antibody for B-cell analysis. The preparations were analyzed for forward and 90/sup 0/ scatter and fluorescence on an Ortho 50H cytofluorograph. Perturbations of peripheral leukocytes occurred after one exposure. After multiple exposures, hematocrit, red-cell number, and hemoglobin were generally depressed, with transient compensatory bursts, and bone marrow cellularity and CFU-S were below normal. However, white-cell numbers fluctuated dramatically during the exposure period. There was a shift in differential toward granulocytes, at times resulting in severely depressed numbers of lymphocytes in the peripheral blood. The FCM analysis showed an early depletion of granulocytes in the bone marrow followed by replacement and a relative lymphocyte deficit, especially pronounced at 10 wk. The B-cell changes reflected general lymphocyte perturbations. Shifts in numbers of cells in S and G/M were observed, consistent with a moderate bone marrow response to cell loss.

  12. Extraction of americium in different oxidation states in a two-phase aqueous system based on poly(ethylene glycol)

    SciTech Connect

    Molochnikova, N.P.; Frenkel', B.F.; Myasoedov, B.F.; Shkinev, V.M.; Spivakov, B.Ya.; Zolotov, Yu.A.

    1987-09-01

    The extraction of americium in different states of oxidation was studied in a two-phase aqueous system based on poly(ethylene glycol). Conditions were found for the quantitative extraction of americium (III) and americium (V) from solutions of ammonium sulfate in the pH range of 3-5 and in the presence of arsenazo III. The composition of the complexes of americium with the reagent was determined; americium (III) reacts with arsenazo III in solutions of ammonium sulfate to form complexes with the composition of MeR and Me/sub 2/R. Characteristics of the absorption spectra of complexes of americium (III) and (V) with arsenazo III in ammonium sulfate solutions and in extracts based on aqueous solutions of poly(ethylene glycol) were found. The molar extinction coefficients of complexes of americium with arsenazo III were determined in these solutions.

  13. Oxidation-Responsive and "Clickable" Poly(ethylene glycol) via Copolymerization of 2-(Methylthio)ethyl Glycidyl Ether.

    PubMed

    Herzberger, Jana; Fischer, Karl; Leibig, Daniel; Bros, Matthias; Thiermann, Raphael; Frey, Holger

    2016-07-27

    Poly(ethylene glycol) (PEG) is a widely used biocompatible polymer. We describe a novel epoxide monomer with methyl-thioether moiety, 2-(methylthio)ethyl glycidyl ether (MTEGE), which enables the synthesis of well-defined thioether-functional poly(ethylene glycol). Random and block mPEG-b-PMTEGE copolymers (Mw/Mn = 1.05-1.17) were obtained via anionic ring opening polymerization (AROP) with molecular weights ranging from 5 600 to 12 000 g·mol(-1). The statistical copolymerization of MTEGE with ethylene oxide results in a random microstructure (rEO = 0.92 ± 0.02 and rMTEG E = 1.06 ± 0.02), which was confirmed by in situ (1)H NMR kinetic studies. The random copolymers are thermoresponsive in aqueous solution, with a wide range of tunable transition temperatures of 88 to 28 °C. In contrast, mPEG-b-PMTEGE block copolymers formed well-defined micelles (Rh ≈ 9-15 nm) in water, studied by detailed light scattering (DLS and SLS). Intriguingly, the thioether moieties of MTEGE can be selectively oxidized into sulfoxide units, leading to full disassembly of the micelles, as confirmed by detection of pure unimers (DLS and SLS). Oxidation-responsive release of encapsulated Nile Red demonstrates the potential of these micelles as redox-responsive nanocarriers. MTT assays showed only minor effects of the thioethers and their oxidized derivatives on the cellular metabolism of WEHI-164 and HEK-293T cell lines (1-1000 μg·mL(-1)). Further, sulfonium PEG polyelectrolytes can be obtained via alkylation or alkoxylation of MTEGE, providing access to a large variety of functional groups at the charged sulfur atom. PMID:27375132

  14. Effect of the potassium permanganate during papaya fruit ripening: Ethylene production

    NASA Astrophysics Data System (ADS)

    Corrêa, S. F.; Filho, M. B.; da Silva, M. G.; Oliveira, J. G.; Aroucha, E. M. M.; Silva, R. F.; Pereira, M. G.; Vargas, H.

    2005-06-01

    The effect of potassium permanganate (KMnO4) on the ripening process of papaya fruits by monitoring the ethylene emission rates is reported. The ethylene emission was monitored by a photoacoustic spectrometer. Two experimental conditions were applied, being one of them just putting the fruit alone inside the sampling chamber and the second, modifying the atmosphere by the presence of KMnO4. The use of the ethylene absorber reduces the autocatalytic process of ethylene during papaya fruit ripening. For 20 g of KMnO4 the maximal intensity of the ethylene emission decreases by a factor two. Using the same amount of KMnO4, a reduction of about 2.2% in the concentration of ethylene for a mixture of 1ppmv of ethylene in synthetic air was observed.

  15. Hydrogen production through aqueous-phase reforming of ethylene glycol in a washcoated microchannel.

    PubMed

    D'Angelo, M Fernanda Neira; Ordomsky, Vitaly; Paunovic, Violeta; van der Schaaf, John; Schouten, Jaap C; Nijhuis, T Alexander

    2013-09-01

    Aqueous-phase reforming (APR) of biocarbohydrates is conducted in a catalytically stable washcoated microreactor where multiphase hydrogen removal enhances hydrogen efficiency. Single microchannel experiments are conducted following a simplified model based on the microreactor concept. A coating method to deposit a Pt-based catalyst on the microchannel walls is selected and optimized. APR reactivity tests are performed by using ethylene glycol as the model compound. Optimum results are achieved with a static washcoating technique; a highly uniform and well adhered 5 μm layer is deposited on the walls of a 320 μm internal diameter (ID) microchannel in one single step. During APR of ethylene glycol, the catalyst layer exhibits high stability over 10 days after limited initial deactivation. The microchannel presents higher conversion and selectivity to hydrogen than a fixed-bed reactor. The benefits of using a microreactor for APR can be further enhanced by utilizing increased Pt loadings, higher reaction temperatures, and larger carbohydrates (e.g., glucose). The use of microtechnology for aqueous-phase reforming will allow for a great reduction in the reformer size, thus rendering it promising for distributed hydrogen production. PMID:23592593

  16. Evaluating the formulae for integrated lethality in ethylene oxide sterilization using six different endospore forming strains of bacteria, and comparisons of integrated lethality for ethylene oxide and steam systems.

    PubMed

    Mosley, Gregg A; Gillis, John R; Krushefski, Garrett

    2005-01-01

    Bacterial endospores from six different species of bacteria were exposed to a spectrum of ethylene oxide (EtO) sterilizing conditions. Temperature was varied from 40 to 60 degrees C and the ethylene oxide concentration was varied from 300 to 750 mg/L. Relative humidity was maintained at 60+/-10% RH. The fraction negative procedure was used to determine the D value for each of the test conditions. Bacterial species tested included Bacillus atrophaeus ATCC # 9372, Bacillus smithii ATCC # 51232, Bacillus subtilis "5230" ATCC # 35021, Bacillus subtilis, DSM # 4181, Bacillus pumilus ATCC # 27142, and Geobacillus stearothermophilus ATCC # 7953. All spore preparations were inoculated on filter paper strips packaged in blue, sterilizable glassine pouches. G. stearothermophilus was the least resistant organism tested. The most resistant organisms tested were B. atrophaeus and B. subtilis "5230". The B. subtilis "5230" strain was slightly more resistant than B. atrophaeus at conditions of 54C and EtO concentrations of 400, 600, and 750 mg/L, as well as at 60C/750mg/L EtO. The other species were between these extremes. This empirical data allowed the application of the recently published formula for converting D values from one set of conditions to another and evaluations of accuracy. The measured D values also allowed the determination of Z values based on temperature variations. These formulae, when applied to process temperatures independent of gas concentration, result in a Z value of approximately 32 degrees C that appears to be similar for all species tested. These data support the application of the previously published formulae 1-6 and allow the same approach to integrated lethality for ethylene oxide processes as is commonly applied to steam sterilization. A review of steam sterilization and related principles was conducted for comparison of integrated lethality for these two methods of sterilization. Errors associated with D values, Z values, extrapolation, and

  17. [Nitric oxide production in plants].

    PubMed

    Małolepsza, Urszula

    2007-01-01

    There are still many controversial observations and opinions on the cellular/subcellular localization and sources of endogenous nitric oxide synthesis in plant cells. NO can be produced in plants by non-enzymatic and enzymatic systems depending on plant species, organ or tissue as well as on physiological state of the plant and changing environmental conditions. The best documented reactions in plant that contribute to NO production are NO production from nitrite as a substrate by cytosolic (cNR) and membrane bound (PM-NR) nitrate reductases (NR), and NO production by several arginine-dependent nitric oxide synthase-like activities (NOS). The latest papers indicate that mitochondria are an important source of arginine- and nitrite-dependent NO production in plants. There are other potential enzymatic sources of NO in plants including xanthine oxidoreductase, peroxidase, cytochrome P450. PMID:18399354

  18. Cell adhesion and growth enabled by biomimetic oligopeptide modification of a polydopamine-poly(ethylene oxide) protein repulsive surface.

    PubMed

    Musilkova, Jana; Kotelnikov, Ilya; Novotna, Katarina; Pop-Georgievski, Ognen; Rypacek, Frantisek; Bacakova, Lucie; Proks, Vladimir

    2015-11-01

    Protein-repulsive surfaces modified with ligands for cell adhesion receptors have been widely developed for controlling the cell adhesion and growth in tissue engineering. However, the question of matrix production and deposition by cells on these surfaces has rarely been addressed. In this study, protein-repulsive polydopamine-poly(ethylene oxide) (PDA-PEO) surfaces were functionalized with an RGD-containing peptide (RGD), with a collagen-derived peptide binding fibronectin (Col), or by a combination of these peptides (RGD + Col, ratio 1:1) in concentrations of 90 fmol/cm(2) and 700 fmol/cm(2) for each peptide type. When seeded with vascular endothelial CPAE cells, the PDA-PEO surfaces proved to be completely non-adhesive for cells. On surfaces with lower peptide concentrations and from days 1 to 3 after seeding, cell adhesion and growth was restored practically only on the RGD-modified surface. However, from days 3 to 7, cell adhesion and growth was improved on surfaces modified with Col and with RGD + Col. At higher peptide concentrations, the cell adhesion and growth was markedly improved on all peptide-modified surfaces in both culture intervals. However, the collagen-derived peptide did not increase the expression of fibronectin in the cells. The deposition of fibronectin on the material surface was generally very low and similar on all peptide-modified surfaces. Nevertheless, the RGD + Col surfaces exhibited the highest cell adhesion stability under a dynamic load, which correlated with the highest expression of talin and vinculin in the cells on these surfaces. A combination of RGD + Col therefore seems to be the most promising for surface modification of biomaterials, e.g. vascular prostheses. PMID:26449443

  19. Ethylene and oxygen species adsorbed on a defect oxidized surface Ag(1 1 1) . Theoretical analysis by DFT method

    NASA Astrophysics Data System (ADS)

    Avdeev, Vasilii I.; Zhidomirov, Georgii M.

    2001-10-01

    We suggest a cluster model AS v→Ag12-3O of the oxidized surface Ag(1 1 1) with a defect. The defect is simulated by cationic vacancy V. Density functional theory (B3LYP/LANL1MB approximation) is used to calculate ethylene and oxygen adsorption on the regular (AS r) and defect (AS d) sites on the Ag(1 1 1). Oxygen interaction with site AS r produces atomic oxygen species (AS r-O). Oxygen adsorption on site AS d is accompanied by its association with subsurface oxygen atoms to form a quasimolecular structure of metal ozonide type -Ag-O-O ep-O-Ag-, containing electrophilic oxygen O ep. Energies of atomic oxygen binding to the regular and defect surfaces are found to be approximately equal. On the regular surface, ethylene forms a π-complex with binding energy Eπ(Ag-C 2H 4)=14.2 kcal/mol. On the defect surface, ethylene produces a metal-ethylene-peroxide cycle such as Ag-O-O-C 2H 4-Ag. Determined are the frequencies of normal vibration for ethylene and oxygen species, adsorbed on the regular and defect surfaces. In the case of associative oxygen species and complete isotope replacement 16O→ 18O, the main frequency at 1000 cm -1 shifts by Δν=57-61 cm -1, but this shift decreases to Δν=25-30 cm -1 for isotope mixtures 16O/ 18O. For the adsorbed species of ethylene-oxygen mixtures, IR spectra show the frequencies within which 170-180 cm -1 are associated with stretching of bond Ag-C. Frequencies at 300-490 cm -1 are assigned to mode ν(Ag-O) of the functional group Ag-O-O ep-O-Ag. The most intensive modes at 950 and 600 cm -1 are likely to stretching and bending of the functional groups containing the O-O-O and O-O-C bonds.

  20. Salt stress-induced production of reactive oxygen- and nitrogen species and cell death in the ethylene receptor mutant Never ripe and wild type tomato roots.

    PubMed

    Poór, Péter; Kovács, Judit; Borbély, Péter; Takács, Zoltán; Szepesi, Ágnes; Tari, Irma

    2015-12-01

    The salt stress triggered by sublethal, 100 mM and lethal, 250 mM NaCl induced ethylene production as well as rapid accumulation of superoxide radical and H2O2 in the root tips of tomato (Solanum lycopersicum cv. Ailsa Craig) wild type and ethylene receptor mutant, Never ripe (Nr/Nr) plants. In the wild type plants superoxide accumulation confined to lethal salt concentration while H2O2 accumulated more efficiently under sublethal salt stress. However, in Nr roots the superoxide production was higher and unexpectedly, H2O2 level was lower than in the wild type under sublethal salt stress. Nitric oxide production increased significantly under sublethal and lethal salt stress in both genotypes especially in mutant plants, while peroxynitrite accumulated significantly under lethal salt stress. Thus, the nitro-oxidative stress may be stronger in Nr roots, which leads to the programmed death of tissues, characterized by the DNA and protein degradation and loss of cell viability under moderate salt stress. In Nr mutants the cell death was induced in the absence of ethylene perception. Although wild type roots could maintain their potassium content under moderate salt stress, K(+) level significantly declined leading to small K(+)/Na(+) ratio in Nr roots. Thus Nr mutants were more sensitive to salt stress than the wild type and the viability of root cells decreased significantly under moderate salt stress. These changes can be attributed to a stronger ionic stress due to the K(+) loss from the root tissues. PMID:26512971

  1. Fourier transform microwave spectrum of the nitrogen molecule-ethylene oxide complex: intracomplex motions.

    PubMed

    Kawashima, Yoshiyuki; Hirota, Eizi

    2013-12-19

    The rotational spectra of the N2-ethylene oxide (EO) complex were measured in the frequency region from 4 to 27 GHz by Fourier transform microwave spectroscopy, paying particular attention to intracomplex motions. The isotopologues with enriched (15)N2 or (15)NN as a moiety were also investigated. We have observed spectra of a strong/weak pair for each of the ortho and para states of the (14)N2-EO and (15)N2-EO species, which indicated that the complex existed in four distinct states. We interpreted, on the basis of the observed relative intensities, that these states were generated primarily by the exchange of the nitrogen atoms of the N2 moiety, followed by that of the two CH2 groups in the EO molecule. The (15)NN-EO species was found to consist of two isomers, one with the (15)N in the inner expressed as N(15)N-EO and the other in the outer position designated as (15)NN-EO, and the spectra of both isomers were accompanied by one weak set of satellites. The observed spectra were rotationally assigned by using sum rules and were analyzed by the asymmetric-rotor program of S-reduction, with the standard deviation of less than 10 kHz. We have found some of the molecular parameters like A, D(JK), and D(K) to be correlated between the two pairs of the spectra, and also, to much less extent, between the strong and weak members. The differences in these molecular parameters between the four sets were explained by the first-order Coriolis interaction between the "ground" and "excited" states generated by a combination of the two internal motions corresponding to the exchanges of the equivalent atoms and/or groups in the N2 and EO constituents of the complex. These internal motions were simulated by the 2-fold internal rotations of the two moieties. We have carried out ab initio molecular orbital calculations at the level of MP2 with basis sets 6-311++G(d,p), aug-cc-pVDZ, and aug-cc-pVTZ, to complement the information on the intracomplex motions obtained from the observed

  2. Membrane protein resistance of oligo(ethylene oxide) self-assembled monolayers.

    PubMed

    Vaish, Amit; Vanderah, David J; Vierling, Ryan; Crawshaw, Fay; Gallagher, D Travis; Walker, Marlon L

    2014-10-01

    As part of an effort to develop biointerfaces for structure-function studies of integral membrane proteins (IMPs) a series of oligo(ethylene oxide) self-assembled monolayers (OEO-SAMs) were evaluated for their resistance to protein adsorption (RPA) of IMPs on Au and Pt. Spectroscopic ellipsometry (SE) was used to determine SAM thicknesses and compare the RPA of HS(CH2)3O(CH2CH2O)6CH3 (1), HS(CH2)3O(CH2CH2O)6H (2), [HS(CH2)3]2CHO(CH2CH2O)6CH3 (3) and [HS(CH2)3]2CHO(CH2CH2O)6H (4), assembled from water. For both substrates, SAM thicknesses for 1 to 4 were found to be comparable indicating SAMs with similar surface coverages and OEO chain order and packing densities. Fibrinogen (Fb), a soluble plasma protein, and rhodopsin (Rd), an integral membrane G-protein coupled receptor, adsorbed to the SAMs of 1, as expected from previous reports, but not to the hydroxy-terminated SAMs of 2 and 4. The methoxy-terminated SAMs of 3 were resistant to Fb but, surprisingly, not to Rd. The stark difference between the adsorption of Rd to the SAMs of 3 and 4 clearly indicate that a hydroxy-terminus of the OEO chain is essential for high RPA of IMPs. The similar thicknesses and high RPA of the SAMs of 2 and 4 show the conditions of protein resistance (screening the underlying substrate, packing densities, SAM order, and conformational mobility of the OEO chains) defined from previous studies on Au are applicable to Pt. In addition, the SAMs of 4, exhibiting the highest resistance to Fb and Rd, were placed in contact with undiluted fetal bovine serum for 2h. Low protein adsorption (≈12.4ng/cm(2)), obtained under these more challenging conditions, denote a high potential of the SAMs of 4 for various applications requiring the suppression of non-specific protein adsorption. PMID:25124834

  3. Engineering a novel biosynthetic pathway in Escherichia coli for production of renewable ethylene glycol.

    PubMed

    Pereira, Brian; Zhang, Haoran; De Mey, Marjan; Lim, Chin Giaw; Li, Zheng-Jun; Stephanopoulos, Gregory

    2016-02-01

    Ethylene glycol (EG) is an important commodity chemical with broad industrial applications. It is presently produced from petroleum or natural gas feedstocks in processes requiring consumption of significant quantities of non-renewable resources. Here, we report a novel pathway for biosynthesis of EG from the renewable sugar glucose in metabolically engineered Escherichia coli. Serine-to-EG conversion was first achieved through a pathway comprising serine decarboxylase, ethanolamine oxidase, and glycolaldehyde reductase. Serine provision in E. coli was then enhanced by overexpression of the serine-biosynthesis pathway. The integration of these two parts into the complete EG-biosynthesis pathway in E. coli allowed for production of 4.1 g/L EG at a cumulative yield of 0.14 g-EG/g-glucose, establishing a foundation for a promising biotechnology. PMID:26221864

  4. A comparison of two methods for selecting vibrational configuration interaction spaces on a heptatomic system: ethylene oxide.

    PubMed

    Bégué, Didier; Gohaud, Neil; Pouchan, Claude; Cassam-Chenaï, Patrick; Liévin, Jacques

    2007-10-28

    Two recently developed methods for solving the molecular vibrational Schrodinger equation, namely, the parallel vibrational multiple window configuration interaction and the vibrational mean field configuration interaction, are presented and compared on the same potential energy surface of ethylene oxide, c-C(2)H(4)O. It is demonstrated on this heptatomic system with strong resonances that both approaches converge towards the same fundamental frequencies. This confirms their ability to tackle the vibrational problem of large molecules for which full configuration interaction calculations are not tractable. PMID:17979327

  5. National emission standards for hazardous air pollutants for ethylene oxide commercial sterilization and fumigation operations--EPA. Interim final rule.

    PubMed

    1998-12-01

    Today's action suspends the National Emission Standards for Hazardous Air Pollutants for Ethylene Oxide Commercial Sterilization and Fumigation Operations (EO NESHAP) requirements for chamber exhaust and aeration room vents. The suspension allows affected sources subject to the EO NESHAP to defer compliance with the NESHAP requirements for chamber exhaust and aeration room vents for one year until December 6, 1999. This suspension does not affect the requirement for sources subject to the EO NESHAP to comply with provisions for sterilizer vents by December 6, 1998. This action does not change the level of the standards or the intent of the NESHAP promulgated in 1994. PMID:10338881

  6. Severe anaphylactic shock due to ethylene oxide in a patient with myelomeningocele: successful exposure prevention and pretreatment with omalizumab.

    PubMed

    Listyo, Adrian; Hofmeier, Kathrin Scherer; Bandschapp, Oliver; Erb, Thomas; Hasler, Carol-Claudius; Bircher, Andreas J

    2014-01-01

    Ethylene oxide (EO) is a highly reactive gas widely used for sterilization of medical devices, for example, plastic materials and ventriculoperitoneal shunts. Allergic reactions to EO are rare and have been observed mainly in patients during hemodialysis and myelomeningocele patients. We describe severe anaphylaxis to EO in a patient with myelomeningocele during general anesthesia. A detailed description is provided about the prevention measures aimed at reducing exposure to EO including a novel approach by resterilization with plasma. Also, pretreatment with omalizumab was implemented for the first time in such a case. With these measures, further surgeries in our patient were uneventful. PMID:25612258

  7. Kinetics of Ethylene and Ethylene Oxide in Subcellular Fractions of Lungs and Livers of Male B6C3F1 Mice and Male Fischer 344 Rats and of Human Livers

    PubMed Central

    Csanády, György András; Kessler, Winfried; Klein, Dominik; Pankratz, Helmut; Pütz, Christian; Richter, Nadine; Filser, Johannes Georg

    2011-01-01

    Ethylene (ET) is metabolized in mammals to the carcinogenic ethylene oxide (EO). Although both gases are of high industrial relevance, only limited data exist on the toxicokinetics of ET in mice and of EO in humans. Metabolism of ET is related to cytochrome P450-dependent mono-oxygenase (CYP) and of EO to epoxide hydrolase (EH) and glutathione S-transferase (GST). Kinetics of ET metabolism to EO and of elimination of EO were investigated in headspace vessels containing incubations of subcellular fractions of mouse, rat, or human liver or of mouse or rat lung. CYP-associated metabolism of ET and GST-related metabolism of EO were found in microsomes and cytosol, respectively, of each species. EH-related metabolism of EO was not detectable in hepatic microsomes of rats and mice but obeyed saturation kinetics in hepatic microsomes of humans. In ET-exposed liver microsomes, metabolism of ET to EO followed Michaelis-Menten-like kinetics. Mean values of Vmax [nmol/(min·mg protein)] and of the apparent Michaelis constant (Km [mmol/l ET in microsomal suspension]) were 0.567 and 0.0093 (mouse), 0.401 and 0.031 (rat), and 0.219 and 0.013 (human). In lung microsomes, Vmax values were 0.073 (mouse) and 0.055 (rat). During ET exposure, the rate of EO production decreased rapidly. By modeling a suicide inhibition mechanism, rate constants for CYP-mediated catalysis and CYP inactivation were estimated. In liver cytosol, mean GST activities to EO expressed as Vmax/Km [μl/(min·mg protein)] were 27.90 (mouse), 5.30 (rat), and 1.14 (human). The parameters are most relevant for reducing uncertainties in the risk assessment of ET and EO. PMID:21785163

  8. Process for the production of ethylene and other hydrocarbons from coal

    DOEpatents

    Steinberg, M.; Fallon, P.

    1984-02-15

    The subject invention comprises the steps of first reacting particulate coal with methane at a temperature in the approximate range of 500/sup 0/C to 1100/sup 0/C and at a partial pressure of methane of less than about 200 psig for a period of less than 10 seconds. More preferably, the method of the subject invention is carried out at a temperature of approximately 850/sup 0/C to 1000/sup 0/C and a pressure of 50 psig for a period of approximately 1.5 seconds. Surprisingly, it has been found that in the practice of the subject invention not only are commercially significant quantities of ethylene produced, namely yields in excess of 10% (percent carbon converted to product), along with economically significant quantities of-benzene and light oils, namely toluene and xylene, but also that there is little, if any, net consumption of methane in the reaction and possibly even a small net production. Since it is apparent that the carbonaceous solids or char remaining after the reaction is carried out may be burned to provide the necessary energy to carry out the process of the subject invention, it is apparent that the subject invention advantageously provides a method for the conversion of coal to economically significant quantities of ethylene, benzene and light oils while requiring only coal and, possibly, small amounts of make-up methane. Other objects and advantages of the subject invention will be apparent to those skilled in the art from a consideration of the attached drawings, the detailed description of the invention, and the experimental examples set forth below.

  9. Ethylene Production and Leaflet Abscission in Mèlia azédarach L. 1

    PubMed Central

    Morgan, Page W.; Durham, James I.

    1980-01-01

    Ethylene production or content was compared to leaflet abscission in detached, compound leaves of Mèlia azédarach L. In late autumn, when abscission was progressing from basal leaves upward, the oldest leaves both produced ethylene at the highest rates and abscised their leaflets first. When C2H4 levels were measured in intercellular air removed immediately after leaves were harvested, C2H4 levels were also highest in basal leaves and declined progressively in more apical leaves. Levels as high as 1.8 microliters C2H4 liter−1 air were observed. Earlier in the season groups of leaves demonstrated a pattern of sequential initiation of abscission from base to apex, but the peak rates of C2H4 production followed an opposite trend, being highest in the youngest leaves. Peak rates of C2H4 production occurred after the initiation of leaflet abscission and presumably are related to either the auxin content or a climacteric-like, autocatalytic phase of C2H4 production not directly involved in the initiation of abscission. In these experiments, the early abscission of the older leaflets reflects their greater sensitivity to C2H4, presumably due to lower auxin content. C2H4 production rates in all experiments, with rare exceptions, exceeded 3 microliters per kilogram fresh weight per hour at least 24 hours before leaflet abscission reached 10%. This achieving of a threshold internal C2H4 level is viewed as an initiating event in leaflet abscission. Hypobaric conditions, to facilitate the escape of endogenous C2H4, delayed abscission compared to controls, and termination of hypobaric exposure allowed a normal progression of abscission as well as normal C2H4 synthesis rates. All of the data indicate that C2H4 initiates leaflet abscission in intact but detached leaves of Mèlia azédarach L. The seasonal patterns observed suggest that C2H4, in concert with those hormones which govern sensitivity to C2H4, regulate autumn leaf fall in this species. PMID:16661401

  10. Modeling and experimental investigation of rheological properties of injectable poly(lactide ethylene oxide fumarate)/hydroxyapatite nanocomposites.

    PubMed

    Sarvestani, Alireza S; Jabbari, Esmaiel

    2006-05-01

    Injectable multiphasic polymer/ceramic composites are attractive as bioresorbable scaffolds for bone regeneration because they can be cross-linked in situ and are osteoconductive. The injectability of the composite depends on the nanoparticle content and the energetic interactions at the polymer/particle interface. The objective of this research was to determine experimentally the rheological properties of the PLEOF/apatite composite as an injectable biomaterial and to compare the viscoelastic response with the predictions of a linear elastic dumbbell model. A degradable in situ cross-linkable terpolymer based on low molecular weight poly(L-lactide) and poly(ethylene oxide) linked by unsaturated fumarate groups is synthesized. The poly(L-lactide-co-ethylene oxide-co-fumarate) (PLEOF) terpolymer interacts with the surface of the apatite nanoparticles by polar interactions and hydrogen bonding. A kinetic model is developed that takes into account the adsorption/desorption of polymer chains to/from the nanoparticle surface. Rheological properties of the aqueous dispersion of PLEOF terpolymer reinforced with nanosized hydroxyapatite (HA) particles are investigated using mechanical rheometry. To this end, we performed a series of rheological experiments on un-cross-linked PLEOF reinforced with different volume fractions of HA nanoparticles. The results demonstrate that the observed nonlinear viscoelasticity at higher shear rates is controlled by the energetic interactions between the polymer chains and dispersed particle aggregates and by the rate of the adsorption/desorption of the chains to/from the surface of the nanoparticles. PMID:16677041

  11. Laboratory validation and field verification of a new passive air monitoring badge for sampling ethylene oxide in air.

    PubMed

    Kring, E V; Damrell, D J; Basilio, A N; McGibney, P D; Douglas, J J; Henry, T J; Ansul, G R

    1984-10-01

    A new diffusion colorimetric air monitoring badge for sampling ethylene oxide is described. The Du Pont Pro-Tek C-70 badge has been laboratory validated over the range of 4-375 ppm-hours (0.5-47 ppm on an 8-hour TWA) using standard spectrophotometer readout in 1 centimeter (10 mm) cells. The lower range can be extended to 2 ppm-hours (0.25 ppm) by using 4 cm (40 mm) cells. The badge has an overall sampling and analytical method accuracy of +/- 13.5%. It meets NIOSH accuracy criteria and has a mean coefficient of variation CVT = 0.059. The badge has no temperature, pressure, relative humidity or face velocity effects over practical ranges. The response time is adequate to sample peak concentrations over short time periods. The badge may be used to determine ambient formaldehyde levels if suspected to be present along with ethylene oxide. Badges are shown to agree very well with the industry accepted and proposed ASTM pump/charcoal tube method in three extensive plant field tests. Badges were more precise than the charcoal tube/pump method in all field tests conducted. PMID:6496316

  12. On the origin of reactivity of steam reforming of ethylene glycol on supported Ni catalysts.

    PubMed

    Li, Shuirong; Zhang, Chengxi; Zhang, Peng; Wu, Gaowei; Ma, Xinbin; Gong, Jinlong

    2012-03-28

    This paper describes a strategy for producing hydrogen via steam reforming of ethylene glycol over supported nickel catalysts. Nickel plays a crucial role in conversion of ethylene glycol and production of hydrogen, while oxide supports affect product distribution of carbonaceous species. A plausible reaction pathway is proposed based on our results and the literature. PMID:22246195

  13. Chloride stress triggers maturation and negatively affects the postharvest quality of persimmon fruit. Involvement of calyx ethylene production.

    PubMed

    Besada, Cristina; Gil, Rebeca; Bonet, Luis; Quiñones, Ana; Intrigliolo, Diego; Salvador, Alejandra

    2016-03-01

    In recent years many hectares planted with persimmon trees in E Spain have been diagnosed with chloride toxicity. An effect of this abiotic stress on fruit quality has been reported in different crops. However, the impact of chloride stress on persimmon fruit quality is unknown. The harvest and postharvest quality of persimmons harvested from trees that manifest different intensities of chloride toxicity foliar symptoms was evaluated herein. Our results revealed that fruits from trees under chloride stress conditions underwent chloride accumulation in the calyx, which was more marked the greater the salt stress intensity trees were exposed to. Increased chloride concentrations in the calyx stimulated ethylene production in this tissue. In the fruits affected by slight and moderate chloride stress, calyx ethylene production accelerated the maturity process, as reflected by increased fruit colour and diminished fruit firmness. In the fruits under severe chloride stress, the high ethylene levels in the calyx triggered autocatalytic ethylene production in other fruit tissues, which led fruit maturity to drastically advance. In these fruits effectiveness of CO2 deastringency treatment was not complete and fruit softening enhanced during the postharvest period. Moreover, chloride stress conditions had a marked effect on reducing fruit weight, even in slightly stressed trees. PMID:26807935

  14. The production of carbon nanofibers and thin films on palladium catalysts from ethylene oxygen mixtures

    SciTech Connect

    Phillips, Jonathan; Doorn, Stephen; Atwater, Mark; Leseman, Zayd; Luhrs, Claudia C; Diez, Yolanda F; Diaz, Angel M

    2009-01-01

    The characteristics of carbonaceous materials deposited in fuel rich ethylene-oxygen mixtures on three types of palladium: foil, sputtered film, and nanopowder, are reported. It was found that the form of palladium has a dramatic influence on the morphology of the deposited carbon. In particular, on sputtered film and powder, tight 'weaves' of sub-micron filaments formed quickly. In contrast, on foils under identical conditions, the dominant morphology is carbon thin films with basal planes oriented parallel to the substrate surface. Temperature, gas flow rate, reactant flow ratio (C2H4:02), and residence time (position) were found to influence both growth rate and type for all three forms of Pd. X-ray diffraction, high-resolution transmission electron microscopy, temperature-programmed oxidation, and Raman spectroscopy were used to assess the crystallinity of the as-deposited carbon, and it was determined that transmission electron microscopy and x-ray diffraction were the most reliable methods for determining crystallinity. The dependence of growth on reactor position, and the fact that no growth was observed in the absence of oxygen support the postulate that the carbon deposition proceeds by combustion generated radical species.

  15. A comparative study of the treatment of ethylene plant spent caustic by neutralization and classical and advanced oxidation.

    PubMed

    Hawari, Alaa; Ramadan, Hasanat; Abu-Reesh, Ibrahim; Ouederni, Mabrouk

    2015-03-15

    The treatment of spent caustic produced from an ethylene plant was investigated. In the case of neutralization alone it was found that the maximum removal of sulfide was at pH values below 5.5. The higher percentage removal of sulfides (99% at pH = 1.5) was accompanied with the highest COD removal (88%). For classical oxidation using H2O2 the maximum COD removal percentage reached 89% at pH = 2.5 and at a hydrogen peroxide concentration of 19 mM/L. For the advanced oxidation using Fenton's process it was found that the maximum COD removal of 96.5% was achieved at a hydrogen peroxide/ferrous sulfate ratio of (7:1). PMID:25546845

  16. Oxidation of methanol, ethylene glycol, and isopropanol with human alcohol dehydrogenases and the inhibition by ethanol and 4-methylpyrazole.

    PubMed

    Lee, Shou-Lun; Shih, Hsuan-Ting; Chi, Yu-Chou; Li, Yeung-Pin; Yin, Shih-Jiun

    2011-05-30

    Human alcohol dehydrogenases (ADHs) include multiple isozymes with broad substrate specificity and ethnic distinct allozymes. ADH catalyzes the rate-limiting step in metabolism of various primary and secondary aliphatic alcohols. The oxidation of common toxic alcohols, that is, methanol, ethylene glycol, and isopropanol by the human ADHs remains poorly understood. Kinetic studies were performed in 0.1M sodium phosphate buffer, at pH 7.5 and 25°C, containing 0.5 mM NAD(+) and varied concentrations of substrate. K(M) values for ethanol with recombinant human class I ADH1A, ADH1B1, ADH1B2, ADH1B3, ADH1C1, and ADH1C2, and class II ADH2 and class IV ADH4 were determined to be in the range of 0.12-57 mM, for methanol to be 2.0-3500 mM, for ethylene glycol to be 4.3-2600mM, and for isopropanol to be 0.73-3400 mM. ADH1B3 appeared to be inactive toward ethylene glycol, and ADH2 and ADH4, inactive with methanol. The variations for V(max) for the toxic alcohols were much less than that of the K(M) across the ADH family. 4-Methylpyrazole (4MP) was a competitive inhibitor with respect to ethanol for ADH1A, ADH1B1, ADH1B2, ADH1C1 and ADH1C2, and a noncompetitive inhibitor for ADH1B3, ADH2 and ADH4, with the slope inhibition constants (K(is)) for the whole family being 0.062-960 μM and the intercept inhibition constants (K(ii)), 33-3000 μM. Computer simulation studies using inhibition equations in the presence of alternate substrate ethanol and of dead-end inhibitor 4MP with the determined corresponding kinetic parameters for ADH family, indicate that the oxidation of the toxic alcohols up to 50mM are largely inhibited by 20 mM ethanol or by 50 μM 4MP with some exceptions. The above findings provide an enzymological basis for clinical treatment of methanol and ethylene glycol poisoning by 4MP or ethanol with pharmacogenetic perspectives. PMID:21167143

  17. Ethylene update

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The gaseous plant hormone ethylene is required for many aspects of plant growth, development and responses to the environment. Potato tubers produce low amounts of ethylene and are highly sensitive to ethylene in the atmosphere. Several responses of potato tubers to endogenous and exogenous ethylene...

  18. Lenghty reverse poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) polymeric micelles and gels for sustained release of antifungal drugs.

    PubMed

    Figueroa-Ochoa, Edgar B; Villar-Alvarez, Eva M; Cambón, Adriana; Mistry, Dharmista; Llovo, José; Attwood, David; Barbosa, Silvia; Soltero, J F Armando; Taboada, Pablo

    2016-08-20

    In this work, we present a detailed study of the potential application of polymeric micelles and gels of four different reverse triblock poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) copolymers (BOnEOmBOn, where n denotes the respective block lengths), specifically BO8EO90BO8, BO14EO378BO14, BO20EO411BO20 and BO21EO385BO21, as effective drug transport nanocarriers. In particular, we tested the use of this kind of polymeric nanostructures as reservoirs for the sustained delivery of the antifungals griseofulvin and fluconazole for oral and topical administration. Polymeric micelles and gels formed by these copolymers were shown to solubilize important amounts of these two drugs and to have a good stability in physiologically relevant conditions for oral or topical administration. These polymeric micellar nanocarriers were able to release drugs in a sustained manner, being the release rate slower as the copolymer chain hydrophobicity increased. Different sustained drug release profiles were observed depending on the medium conditions. Gel nanocarriers were shown to display longer sustained release rates than micellar formulations, with the existence of a pulsatile-like release mode under certain solution conditions as a result of their inner network structure. Certain bioadhesive properties were observed for the polymeric physical gels, being moderately tuned by the length and hydrophobicity of the polymeric chains. Furthermore, polymeric gels and micelles showed activity against the yeast Candida albicans and the mould demartophytes (Trichophyton rubrum and Microsporum canis) and, thus, may be useful for the treatment of different cutaneous fungal infections. PMID:27289012

  19. The polymerization and electrochemical characterization of polypyrrole and polypyrrole/poly(ethylene oxide)pyrrole copolymers

    NASA Astrophysics Data System (ADS)

    Huntoon, Trey William Stevens

    1998-11-01

    The work contained within this document discusses the polymerization and subsequent characterization of Polypyrrole based electrodes for lithium batteries. Polypyrrole and Polypyrrole/polyethyloxy copolymers were compared and contrasted in an attempt to show the superior kinetics of the copolymer electrode. It was found that the diffusion of dopant ions across the electrode and electrolyte interface was increased by on order of magnitude in the copolymer sample. It was also found that the reversibility of the Polypyrrole electrode was greater than that of the copolymer electrode. While the diffusion coefficient of the copolymer electrode was altered to be comparable to that of the transition metal oxide cathodes in production today, the capacity of the copolymer material is still too low to be considered as an alternative cathode material in the lithium battery industry.

  20. Non-invasive topical drug delivery to spinal cord with carboxyl-modified trifunctional copolymer of ethylene oxide and propylene oxide.

    PubMed

    Kamalov, Marat I; Lavrov, Igor A; Yergeshov, Abdulla A; Siraeva, Zulfira Y; Baltin, Maxim E; Rizvanov, Albert A; Kuznetcova, Svetlana V; Petrova, Natalia V; Savina, Irina N; Abdullin, Timur I

    2016-04-01

    In this study the effect of oxidative modification on micellar and drug delivery properties of copolymers of ethylene oxide (EO) and propylene oxide (PO) was investigated. Carboxylated trifunctional copolymers were synthesized in the reaction with chromium(VI) oxide. We found that carboxylation significantly improved the uniformity and stability of polymeric micelles by inhibiting the microphase transition. The cytotoxicity of copolymers was studied in relation to their aggregative state on two cell types (cancer line vs. primary fibroblasts). The accumulation of rhodamine 123 in neuroblastoma SH-SY5Y cells was dramatically increased in the presence of the oxidized block copolymer with the number of PO and EO units of 83.5 and 24.2, respectively. The copolymer was also tested as an enhancer for topical drug delivery to the spinal cord when applied subdurally. The oxidized copolymer facilitated the penetration of rhodamine 123 across spinal cord tissues and increased its intraspinal accumulation. These results show the potential of using oxidized EO/PO based polymers for non-invasive delivery of protective drugs after spinal cord injury. PMID:26764102

  1. Highly oxidized graphene oxide and methods for production thereof

    DOEpatents

    Tour, James M.; Kosynkin, Dmitry V.

    2016-08-30

    A highly oxidized form of graphene oxide and methods for production thereof are described in various embodiments of the present disclosure. In general, the methods include mixing a graphite source with a solution containing at least one oxidant and at least one protecting agent and then oxidizing the graphite source with the at least one oxidant in the presence of the at least one protecting agent to form the graphene oxide. Graphene oxide synthesized by the presently described methods is of a high structural quality that is more oxidized and maintains a higher proportion of aromatic rings and aromatic domains than does graphene oxide prepared in the absence of at least one protecting agent. Methods for reduction of graphene oxide into chemically converted graphene are also disclosed herein. The chemically converted graphene of the present disclosure is significantly more electrically conductive than is chemically converted graphene prepared from other sources of graphene oxide.

  2. Quantification of Ethylene Production in Tomato Leaves Infected by Xanthomonas euvesicatoria

    PubMed Central

    Kim, Jung-Gun; Stork, William; Mudgett, Mary Beth

    2016-01-01

    Ethylene is a gaseous plant hormone controlling fruit ripening, flower opening, leaf senescence as well as abscission, and disease symptom development. Ethylene plays a critical role in the bacterial pathogen Xanthomonas euvesicatoria (X. euvesicatoria)-elicited symptom development in tomato. This protocol describes the measurement of ethylene gas produced by tomato leaves infected with X. euvesicatoria. Infected leaflets are placed in a glass tube for 30 min without sealing. The glass tubes are then capped with a septa stopper, and incubated for an hour. A 1 ml gas sample is removed from the tube using a syringe and then injected into a gas chromatograph to quantify ethylene gas levels. This protocol will be applicable for other plants with other pathogens with modifications.

  3. Density-functional investigation of the geometric and electronic structure of ethylene oxide adsorbed on Si(100)

    NASA Astrophysics Data System (ADS)

    Wang, Lu; Li, Qing-Fang; Yang, Cui-Hong; Wei, Yue-Ling; Zhu, Xing-Feng; Rao, Wei-Feng

    2016-05-01

    The geometric and electronic structures of the ethylene oxide (EO) molecule adsorbed on Si(100)-(2 × 1) surface were investigated by using the density-functional theory calculations. All possible adsorbed structures were considered and it was found that only four adsorption structures are stable. The calculations of the formation energy revealed the most stable conformation and demonstrated that the nature of Si-O bond significantly affects the stability of adsorption systems. The analysis of corresponding electronic structures showed that two adsorbed structures are still semiconductor compounds but the other two are not. In particular, the EO after adsorbing was found to be connected via a ring-opening reaction where the molecule forms a five-membered ring together with the surface of dimer silicon atoms, and the produced five-membered ring is almost perpendicular to the silicon surface.

  4. The structure of poly(ethylene oxide) liquids : comparison of integral equation theory with molecular dynamics simulations and neutron scaling.

    SciTech Connect

    Curro, John G.; Frischknecht, Amalie Lucile

    2005-01-01

    Polymer reference interaction site model (PRISM) calculations and molecular dynamics (MD) simulations were carried out on poly(ethylene oxide) liquids using a force field of Smith, Jaffe, and Yoon. The intermolecular pair correlation functions and radius of gyration from theory were in very good agreement with MD simulations when the partial charges were turned off. When the charges were turned on, considerably more structure was seen in the intermolecular correlations obtained from MD simulation. Moreover, the radius of gyration increased by 38% due to electrostatic repulsions along the chain backbone. Because the partial charges greatly affect the structure, significant differences were seen between the PRISM calculations (without charges) and the wide angle neutron scattering measurements of Annis and coworkers for the total structure factor, and the hydrogen/hydrogen intermolecular correlation function. This is in contrast to previous PRISM calculations on poly (dimethyl siloxane).

  5. Second-generation locking mechanisms and ethylene oxide sterilization reduce tibial insert backside damage in total knee arthroplasty.

    PubMed

    Azzam, Michael G; Roy, Marcel E; Whiteside, Leo A

    2011-06-01

    This study evaluated the effects of polyethylene quality and locking mechanism on damage to the nonarticulating (backside) surface of retrieved tibial inserts in total knee arthroplasty. Inserts with peripheral capture (PC) locking mechanisms and ethylene oxide (EtO)-sterilized polyethylene were hypothesized to prevent major backside damage. A total of 156 inserts were sorted by locking mechanism and sterilization method and analyzed by damage scoring methods. Ninety-seven specimens exhibited burnishing. Significant positive linear correlations were observed between damage score and age in vivo for all combinations, but damage occurred at a significantly lower rate for second-generation PC implants with EtO sterilization. Most specimens in this group were undamaged (46/72), with others exhibiting only burnishing. Sex, body mass index, and weight did not influence backside damage. PMID:20541356

  6. Structure and dynamics of water near the interface with oligo(ethylene oxide) self-assembled monolayers.

    PubMed

    Ismail, Ahmed E; Grest, Gary S; Stevens, Mark J

    2007-07-31

    We performed molecular dynamics simulations of the oligo(ethylene oxide) (OEO) self-assembled monolayers in water to determine the nature of the systems' interfacial structure and dynamics. The density profiles, hydrogen bonding, and water dynamics are calculated as a function of the area per molecule A of OEO. At the highest coverages, the interface is hydrophobic, and a density drop is found at the interface. The interfacial region becomes more like bulk water as A increases. The OEO and water become progressively more mixed, and hydrogen bonding increases within the interfacial region. Water mobility is slower within the interfacial region, but not substantially. The implications of our results on the resistance of OEO SAMs to protein adsorption are discussed. Our principal result is that as A increases the increasingly waterlike interfacial region provides a more protein-resistant surface. This finding supports recent experimental measurements that protein resistance is maximal for less than full coverage on Au. PMID:17622160

  7. Efficient Crystalline Si/Poly(ethylene dioxythiophene):Poly(styrene sulfonate):Graphene Oxide Composite Heterojunction Solar Cells

    NASA Astrophysics Data System (ADS)

    Ono, Masahiro; Tang, Zeguo; Ishikawa, Ryo; Gotou, Takuya; Ueno, Keiji; Shirai, Hajime

    2012-03-01

    Efficient crystalline silicon (c-Si) heterojunction solar cells with conductive poly(ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and graphene oxide (GO) composite are demonstrated using a structure of Ag/PEDOT:PSS/PEDOT:PSS:GO composite/c-Si (100)(ρ: 3-5 Ω.cm)/Al. The power-conversion efficiency η increased to 10.7% under illumination of AM1.5 100 mW/cm2 simulated solar light by adjusting the PEDOT:PSS and GO mixing concentration ratio. The GO addition to conductive PEDOT:PSS suppressed electron recombination and/or promoted the hole current at the anode. The soluble PEDOT:PSS:GO composite is promising as a hole-transporting transparent conducting layer for c-Si photovoltaic applications.

  8. Morphological Control of Poly(ethylene oxide)/Polystyrene Blend Thin Films by Using Supercritical Carbon Dioxide

    NASA Astrophysics Data System (ADS)

    Chen, Xiameng

    Polymer blend thin films have been paid great attention to technological applications including adhesion, coatings, liquid crystal alignment, electronics, optics, biotechnology, and sensors. In this thesis, I investigated the effect of supercritical CO2 (scCO2) as a green solvent for poly(ethylene oxide)/polystyrene (PEO/PS) blend thin films. We prepared a series of PEO/PS blend thin films with different PEO compositions thickness ranging from 20 nm to 50 nm. As a control experiment, we also processed the same PEO/PS films at high temperature (150 °C) under vacuum. Comparison of these experimental results by using atomic force microscopy and optical microscopy clarified the significant plasticization effect of scCO2 on the phase separation, crystallization of PEO, and the swelling behavior of PS.

  9. The effect of ethylene oxide sterilization on the surface chemistry and in vitro cytotoxicity of several kinds of chitosan.

    PubMed

    França, Rodrigo; Mbeh, Doris A; Samani, Taraneh Djavanbakht; Le Tien, Canh; Mateescu, Mircea A; Yahia, L'hocine; Sacher, Edward

    2013-06-01

    The surfaces of three chitosan samples, differing only in their degrees of deacetylation and of carboxyethyl chitosan were chemically characterized by X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectroscopy, X-ray diffraction, and Fourier transform infrared, both before and after sterilization with ethylene oxide. Unexpected elemental ratios suggest that surface chemical modification occurred during the processing of the original chitin, with further surface modification on subsequent sterilization, despite previous reports to the contrary. Cell viability was evaluated by direct contact methyl thiazole tetrazolium and lactate dehydrogenase assays between the chitosan particles and A549 human epithelial cells, which demonstrated that the modifications incurred on sterilization are reflected in biocompatibility changes. All the samples were found to be biocompatible and nontoxic before sterilization and remained so subsequently. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013. PMID:23744606

  10. The effect of ethylene oxide sterilization on the surface chemistry and in vitro cytotoxicity of several kinds of chitosan.

    PubMed

    França, Rodrigo; Mbeh, Doris A; Samani, Taraneh Djavanbakht; Le Tien, Canh; Mateescu, Mircea A; Yahia, L'Hocine; Sacher, Edward

    2013-11-01

    The surfaces of three chitosan samples, differing only in their degrees of deacetylation and of carboxyethyl chitosan were chemically characterized by X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectroscopy, X-ray diffraction, and Fourier transform infrared, both before and after sterilization with ethylene oxide. Unexpected elemental ratios suggest that surface chemical modification occurred during the processing of the original chitin, with further surface modification on subsequent sterilization, despite previous reports to the contrary. Cell viability was evaluated by direct contact methyl thiazole tetrazolium and lactate dehydrogenase assays between the chitosan particles and A549 human epithelial cells, which demonstrated that the modifications incurred on sterilization are reflected in biocompatibility changes. All the samples were found to be biocompatible and nontoxic before sterilization and remained so subsequently. PMID:24591223

  11. Organosilicon compounds containing nitrile and oligo(ethylene oxide) substituents as safe electrolytes for high-voltage lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Yong, Tianqiao; Wang, Jinglun; Mai, Yongjin; Zhao, Xinyue; Luo, Hao; Zhang, Lingzhi

    2014-05-01

    Organosilicon compounds containing nitrile and oligo(ethylene oxide) substituents are synthesized as safe electrolytes for high-voltage lithium-ion batteries. We firstly report that these organosilicon electrolytes could be stably cycled at an upper cutoff voltage of 4.4 V in LiCoO2/graphite full cells.

  12. Miscibility of poly(lactic acid) and poly(ethylene oxide) solvent polymer blends and nanofibers made by solution blow spinning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The miscibility of blends of poly(lactic acid) (PLA) and poly(ethylene oxide) (PEO) was studied in polymer solutions by dilute solution viscometry and in solution blow spun nanofibers by microscopy (SEM, TEM) and by thermal and spectral analysis. Three blends of PLA and PEO were solution blended in...

  13. Characterization and assessment of a novel poly(ethylene oxide)/polyurethane composite hydrogel (Aquavene) as a ureteral stent biomaterial.

    PubMed

    Gorman, S P; Tunney, M M; Keane, P F; Van Bladel, K; Bley, B

    1998-03-15

    The effective long-term use of indwelling ureteral stents is often hindered by the formation of encrusting deposits which may cause obstruction and blockage of the stent. Development of improved ureteral stent biomaterials capable of preventing or reducing encrustation is therefore particularly desirable. In this study, the suitability as a ureteral stent biomaterial of Aquavene, a novel poly(ethylene oxide)/polyurethane composite hydrogel was compared with that of silicone and polyurethane, two materials widely employed in ureteral stent manufacture. Examination of Aquavene in dry and hydrated states by confocal laser scanning microscopy, scanning electron microscopy, and atomic force microscopy showed the presence of numerous channels within a cellular matrix structure. The channel size increased considerably to as much as 10 microm in diameter in the hydrated state. Aquavene provided superior resistance to encrustation and intraluminal blockage over a 24-week period in a simulated urine flow model. Unobstructed urine flow continued with Aquavene at 24 weeks, whereas silicone and polyurethane stents became blocked with encrustation at 8 and 10 weeks, respectively. Weight loss within Aquavene on the order of 9% (w/w) over the 24-week flow period indicates that extraction of the noncrosslinked poly(ethylene oxide) hydrogel may be responsible for the prevention of encrustation blockage of this biomaterial. In the dry state, Aquavene was significantly harder than either silicone or polyurethane, as shown by Young's modulus, and rapidly became soft on hydration. These additional properties of Aquavene would facilitate ease of stent insertion in the dry state past obstructions in the ureter and provide improved patient comfort on subsequent biomaterial hydration in situ. Aquavene is a promising candidate for use in the urinary tract, as it is probable that effective long-term urine drainage would be maintained in vivo. Further evaluation of this novel biomaterial is

  14. Truffles Regulate Plant Root Morphogenesis via the Production of Auxin and Ethylene1[C][W][OA

    PubMed Central

    Splivallo, Richard; Fischer, Urs; Göbel, Cornelia; Feussner, Ivo; Karlovsky, Petr

    2009-01-01

    Truffles are symbiotic fungi that form ectomycorrhizas with plant roots. Here we present evidence that at an early stage of the interaction, i.e. prior to physical contact, mycelia of the white truffle Tuber borchii and the black truffle Tuber melanopsorum induce alterations in root morphology of the host Cistus incanus and the nonhost Arabidopsis (Arabidopsis thaliana; i.e. primary root shortening, lateral root formation, root hair stimulation). This was most likely due to the production of indole-3-acetic acid (IAA) and ethylene by the mycelium. Application of a mixture of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid and IAA fully mimicked the root morphology induced by the mycelium for both host and nonhost plants. Application of the single hormones only partially mimicked it. Furthermore, primary root growth was not inhibited in the Arabidopsis auxin transport mutant aux1-7 by truffle metabolites while root branching was less effected in the ethylene-insensitive mutant ein2-LH. The double mutant aux1-7;ein2-LH displayed reduced sensitivity to fungus-induced primary root shortening and branching. In agreement with the signaling nature of truffle metabolites, increased expression of the auxin response reporter DR5∷GFP in Arabidopsis root meristems subjected to the mycelium could be observed, confirming that truffles modify the endogenous hormonal balance of plants. Last, we demonstrate that truffles synthesize ethylene from l-methionine probably through the α-keto-γ-(methylthio)butyric acid pathway. Taken together, these results establish the central role of IAA and ethylene as signal molecules in truffle/plant interactions. PMID:19535471

  15. Arabidopsis ethylene-response gene ETR1: Similiarity of product to two-component regulators

    SciTech Connect

    Chang, C.; Kwok, S.F.; Bleecker, A.B.; Meyerowitz, E.M. )

    1993-10-22

    Ethylene behaves as a hormone in plants, regulating such aspects of growth and development as fruit ripening, flower senescence, and abscission. Ethylene insensitivity is conferred by dominant mutations in the ETR1 gene early in the ethylene signal transduction pathway of Arabidopsis thaliana. The ETR1 gene was cloned by the method of chromosome walking. Each of the four known etr1 mutant alleles contains a missense mutation near the amino terminus of the predicted protein. Although the sequence of the amino-terminal half of the deduced ETR1 protein appears to be novel, the carboxyl-terminal half is similar in sequence to both components of the prokaryotic family of signal transducers known as the two-component systems. Thus, an early step in ethylene signal transduction in plants may involve transfer of phosphate as in prokaryotic two-component systems. The dominant etr1-1 mutant gene conferred ethylene insensitivity to wild-type Arabidopsis plants when introduced by transformation.

  16. Transparent conducting oxides and production thereof

    DOEpatents

    Gessert, Timothy A; Yoshida, Yuki; Coutts, Timothy J

    2014-05-27

    Transparent conducting oxides and production thereof are disclosed. An exemplary method of producing a transparent conducting oxide (TCO) material may comprise: providing a TCO target (110) doped with either a high-permittivity oxide or a low-permittivity oxide in a process chamber (100). The method may also comprise depositing a metal oxide on the target (110) to form a thin film having enhanced optical properties without substantially decreasing electrical quality.

  17. Transparent conducting oxides and production thereof

    DOEpatents

    Gessert, Timothy A.; Yoshida, Yuki; Coutts, Timothy J.

    2014-06-10

    Transparent conducting oxides and production thereof are disclosed. An exemplary method of producing a transparent conducting oxide (TCO) material may comprise: providing a TCO target doped with either a high-permittivity oxide or a low-permittivity oxide in a process chamber. The method may also comprise depositing a metal oxide on the target in the process chamber to form a thin film having enhanced optical properties without substantially decreasing electrical quality.

  18. Induction of glutathione-S-transferase and heat-shock proteins in rat liver after ethylene oxide exposure.

    PubMed

    Katoh, T; Ohmori, H; Murakami, T; Karasaki, Y; Higashi, K; Muramatsu, M

    1991-08-22

    Defense mechanisms in rat liver against depletion of glutathione (GSH) and cellular injuries induced by ethylene oxide (EO) were studied. Rats were exposed to EO under either high dose (1300 ppm for 4 hr, once) or low dose (500 ppm for 6 hr, three times a week for 6 weeks) conditions. The hepatic content of GSH decreased dramatically after EO treatment, probably due to detoxication of EO. After the high dose treatment the hepatic GSH content fell by 90% of the control values but recovered within 10 to 15 hr. EO reacts directly with a variety of cellular macromolecules but all rats survived the exposure. Since the metabolites of EO are ethylene glycol and GSH-conjugates, the enzymatic activities of epoxide hydrolase and glutathione-S-transferase (GST) were determined. Only GST activity was found to occur after low dose chronic exposure. The defense mechanism at mRNA level was investigated using probes for GST and several heat-shock proteins (hsps). Enhanced accumulation of GST mRNA was detectable during the recovery period of rats after both high and low dose exposure to EO. Interestingly, both hsp32 (less than 40-fold) and hsp90 (less than 3-fold) mRNA increased after high dose exposure but the mRNA level of one of the major heat-shock proteins, hsp70, did not change under these conditions. Diethylmaleate, which is known to be a GSH depleter in liver, induced hsp32 mRNA only in rat liver, while hsp70 and hsp90 mRNA levels did not change when GSH was depleted. These results suggest that individual heat-shock proteins are induced in different ways under unphysiological conditions such as EO exposure. PMID:1888334

  19. One-step sonochemical synthesis of a graphene oxide-manganese oxide nanocomposite for catalytic glycolysis of poly(ethylene terephthalate)

    NASA Astrophysics Data System (ADS)

    Park, Gle; Bartolome, Leian; Lee, Kyoung G.; Lee, Seok Jae; Kim, Do Hyun; Park, Tae Jung

    2012-06-01

    Ultrasound-assisted synthesis of a graphene oxide (GO)-manganese oxide nanocomposite (GO-Mn3O4) was conducted without further modification of GO or employing secondary materials. With the GO nanoplate as a support, potassium permanganate oxidizes the carbon atoms in the GO support and gets reduced to Mn3O4. An intensive ultrasound method could reduce the number of reaction steps and temperature, enhance the reaction rate and furthermore achieve a Mn3O4 phase. The composite was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The coverage and crystallinity of Mn3O4 were controlled by changing the ratio of permanganate to GO dispersion. The synthesized nanocomposite was used as a catalyst for poly(ethylene terephthalate) (PET) depolymerization into its monomer, bis(2-hydroxylethyl) terephthalate (BHET). The highest monomer yield of 96.4% was obtained with the nanocomposite containing the lowest amount of Mn3O4, while PET glycolysis with the Mn3O4 without GO yielded 82.7% BHET.Ultrasound-assisted synthesis of a graphene oxide (GO)-manganese oxide nanocomposite (GO-Mn3O4) was conducted without further modification of GO or employing secondary materials. With the GO nanoplate as a support, potassium permanganate oxidizes the carbon atoms in the GO support and gets reduced to Mn3O4. An intensive ultrasound method could reduce the number of reaction steps and temperature, enhance the reaction rate and furthermore achieve a Mn3O4 phase. The composite was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The coverage and crystallinity of Mn3O4 were controlled by changing the ratio of permanganate to GO dispersion. The synthesized nanocomposite was used as a catalyst for poly(ethylene

  20. Ethylene glycol poisoning

    MedlinePlus

    ... attempt or as a substitute for drinking alcohol (ethanol). This article is for information only. Do NOT ... attempt or as a substitute for drinking alcohol (ethanol). Ethylene glycol is found in many household products, ...

  1. The production of stress ethylene relative to the concentration of heavy metals and other elements in the lichen Hypogymnia physodes

    SciTech Connect

    Garty, J.; Kauppi, M.; Kauppi, A.

    1997-11-01

    The objective of this study was to examine fluctuations in the production of ethylene by the lichen, Hypogymnia physodes, indicative of environmental stress caused by air pollutants. In addition, the authors investigated the accumulation capacity of H. physodes, transplanted in the vicinity of two streets having slow traffic and a highway in the city of Oulu, N. Finland, for a short period (45 d). The amounts of stress ethylene produced by the transplanted lichens was compared with the amounts of airborne elements accumulated in the thallus. H. physodes manifested a high accumulation capacity for Fe and Mg in thalli exposed in either one or both streets with slow traffic in Oulu in comparison with thalli left on the control site in the forest outside of the city. Two of the observed elements, Zn and Fe, exhibited a significant positive correlation with the ethylene concentration detected concomitant in thalli retrieved from one or both streets with slow traffic were higher than the concentrations in thalli transplanted in a highway with 25,240 cars/d after 45 d of exposure. The data thus suggest that the streets with slow traffic and fewer cars are more polluted than the highway.

  2. One step growth of protein antifouling surfaces: monolayers of poly(ethylene oxide) (PEO) derivatives on oxidized and hydrogen-passivated silicon surfaces.

    PubMed

    Cecchet, Francesca; De Meersman, Benoît; Demoustier-Champagne, Sophie; Nysten, Bernard; Jonas, Alain M

    2006-01-31

    We compare two routes for creating protein adsorption-resistant self-assembled monolayers (SAMs) by chemical modification of silicon surfaces with poly(ethylene oxide) (PEO) oligomeric derivatives. The first route involves the assembly of 2-methyl[(polyethyleneoxy)propyl]trichlorosilane (Cl3SiMPEO) films onto oxidized silicon surfaces (OH-SiO(x)) either by a liquid-phase process at room temperature or by a gas-phase process at 423 K, producing Si-O-Si bonds between the substrate and the organic layer. The second pathway makes use of the assembly of poly(ethylene glycol methyl ether) (MPEG) films onto hydrogen-passivated silicon surfaces (H-Si) using a liquid-phase process at 353 or 423 K, leading to the formation of Si-O-C bonds between the substrate and the organic layer. Structural investigation by X-ray reflectometry (XRR) reveals that the thickness and surface densities of the grafted PEO monolayers strongly depend on experimental conditions such as temperature and grafting time. Atomic force microscopy (AFM) shows that very smooth and homogeneous monolayers can be obtained with average roughnesses close to those measured on the corresponding bare substrates. Finally, the antifouling properties of the modified silicon surfaces were evaluated by X-ray photoelectron spectroscopy (XPS), using a membrane protein (P.69 antigen) as model protein. Both types of PEO monolayers exhibit excellent protein repellency, as soon as the grafting density is equal to or higher than 1.7 chains/nm2. PMID:16430281

  3. The influence of Ir and Pt1Ir1 structure in metallic multilayers nanoarchitectured electrodes towards ethylene glycol electro-oxidation

    NASA Astrophysics Data System (ADS)

    Freitas, R. G.; Antunes, E. P.; Christensen, P. A.; Pereira, E. C.

    2012-09-01

    This paper presents a study of the electro-oxidation of ethylene glycol (EG) at metallic multilayer electrodes: Ptpc/Irx/Pty (Ptpc = polycrystalline Pt, x and y denote the number of monolayers of Ir intralayer and Pt outer layer, respectively) and Ptpc/(Pt1Ir1)x/Pty (ie a 1:1 alloy of Pt and Ir was employed as intralayer). For comparison, data are also presented for Ptpc. Although Pt and Ir have similar crystallographic structures, the work reported shows for the first time that the electrocatalytic properties of the Pt outer layer are affected significantly by the composition of the intralayer. The voltammetry data show that the Ptpc/Ir3.0/Pt3.0 metallic multilayer electrode exhibits a peak current density 78% higher than that observed using Ptpc, in agreement with activation energy measurements on the electro-oxidation of EG which showed: Ptpc/Ir3.0/Pt3.0 (26 kJ mol-1) < Ptpc (44 kJ mol-1) < Ptpc/(Pt1Ir1)3.0/Pt3.0 (46 kJ mol-1). The FTIR experiments showed that the main products for the oxidation of the diol at the electrodes are similar: COL, CO2 and glycolic and/or oxalic acid over Ptpc and Ptpc/Ir3.0/Pt3.0 metallic multilayer electrodes. However, significantly more CO2 and COL were observed at Ptpc/Ir3.0/Pt3.0 compared to Ptpc electrodes.

  4. One-step sonochemical synthesis of a graphene oxide-manganese oxide nanocomposite for catalytic glycolysis of poly(ethylene terephthalate).

    PubMed

    Park, Gle; Bartolome, Leian; Lee, Kyoung G; Lee, Seok Jae; Kim, Do Hyun; Park, Tae Jung

    2012-07-01

    Ultrasound-assisted synthesis of a graphene oxide (GO)-manganese oxide nanocomposite (GO-Mn(3)O(4)) was conducted without further modification of GO or employing secondary materials. With the GO nanoplate as a support, potassium permanganate oxidizes the carbon atoms in the GO support and gets reduced to Mn(3)O(4). An intensive ultrasound method could reduce the number of reaction steps and temperature, enhance the reaction rate and furthermore achieve a Mn(3)O(4) phase. The composite was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The coverage and crystallinity of Mn(3)O(4) were controlled by changing the ratio of permanganate to GO dispersion. The synthesized nanocomposite was used as a catalyst for poly(ethylene terephthalate) (PET) depolymerization into its monomer, bis(2-hydroxylethyl) terephthalate (BHET). The highest monomer yield of 96.4% was obtained with the nanocomposite containing the lowest amount of Mn(3)O(4), while PET glycolysis with the Mn(3)O(4) without GO yielded 82.7% BHET. PMID:22592889

  5. ACR process for ethylene

    SciTech Connect

    Baldwin, R.L.; Kamm, G.R.

    1983-01-01

    Describes how the advanced cracking reactor process, which is ready for a logical commercial application, offers total liquids feedstock flexibility from light naphthenes through vacuum gas oils in the same production unit. Several processes are presently being developed which are aimed at maintaining olefin selectivity when cracking the heaviest feeds. Addresses the problems posed by such heavy feedstocks. The following trends favor the ACR process in the 1980s: natural gas price decontrol; limited natural gas reserves; few new domestic LPG-based ethylene plants will be built; an economic recovery will create the need for more ethylene capacity; modest increases in ''real'' crude oil prices; plentiful supplies of vacuum gas oil at prices making it an attractive ethylene feedstock; and increasing supplies of light naphtha at prices making it an attractive ethylene feedstock as well. Predicts that these factors will swing the preferred feedstocks for ethylene manufacture back to crude oil distillates before the end of the decade. Argues that in this environment, the ACR process can deliver the lowest cost ethylene in the industry. ACR has full-range feedstock flexibility, high selectivity to ethylene, and less sensitivity to feedstock costs and co-product credits.

  6. Synthesis of polymer electrolyte membranes from cellulose acetate/poly(ethylene oxide)/LiClO4 for lithium ion battery application

    NASA Astrophysics Data System (ADS)

    Nurhadini, Arcana, I. Made

    2015-09-01

    This study was conducted to determine the effect of cellulose acetate on poly(ethylene oxide)-LiClO4 membranes as the polymer electrolyte. Cellulose acetate is used as an additive to increase ionic conductivity and mechanical property of polymer electrolyte membranes. The increase the percentage of cellulose acetate in membranes do not directly effect on the ionic conductivity, and the highest ionic conductivity of membranes about 5,7 × 10-4 S/cm was observed in SA/PEO/LiClO4 membrane with cellulose ratio of 10-25% (w/w). Cellulose acetate in membranes increases mechanical strength of polymer electrolyte membranes. Based on TGA analysis, this polymer electrolyte thermally is stable until 270 °C. The polymer electrolyte membrane prepared by blending the cellulose acetate, poly(ethylene oxide), and lithium chlorate could be potentially used as a polymer electrolyte for lithium ion battery application.

  7. Synthesis of polymer electrolyte membranes from cellulose acetate/poly(ethylene oxide)/LiClO{sub 4} for lithium ion battery application

    SciTech Connect

    Nurhadini, Arcana, I Made

    2015-09-30

    This study was conducted to determine the effect of cellulose acetate on poly(ethylene oxide)-LiClO{sub 4} membranes as the polymer electrolyte. Cellulose acetate is used as an additive to increase ionic conductivity and mechanical property of polymer electrolyte membranes. The increase the percentage of cellulose acetate in membranes do not directly effect on the ionic conductivity, and the highest ionic conductivity of membranes about 5,7 × 10{sup −4} S/cm was observed in SA/PEO/LiClO{sub 4} membrane with cellulose ratio of 10-25% (w/w). Cellulose acetate in membranes increases mechanical strength of polymer electrolyte membranes. Based on TGA analysis, this polymer electrolyte thermally is stable until 270 °C. The polymer electrolyte membrane prepared by blending the cellulose acetate, poly(ethylene oxide), and lithium chlorate could be potentially used as a polymer electrolyte for lithium ion battery application.

  8. Interaction of poly(ethylene oxide) with the sodium dodecyl sulfate micelle interface studied with nitroxide spin probes

    SciTech Connect

    Kang, Y.S.; Kevan, L. )

    1994-08-04

    Electron spin resonance (ESR) line widths of 5-, 7-, 12-, and 16-doxylstearic acid (x-DSA) and tempo nitroxides versus the concentration of poly(ethylene oxide) (PEO) in sodium dodecyl sulfate (SDS) micelles show different trends. The ESR line widths of 5-, 7-, and 16-DSA increase with increasing concentration of PEO, which is interpreted as due to increasing viscosity in the environment of the nitroxide spin probe. The tempo and 12-DSA line widths were independent of the concentration of PEO. The line width showed the highest value for 5-DSA and the lowest value of tempo. The line width of x-DSA decreases from 5-DSA to a minimum value for 12-DSA and then increases somewhat for 16-DSA. This is interpreted as bending of the alkyl chain to provide different locations for the nitroxide moiety relative to the micelle interface. The relative distances of the nitroxide moiety of [chi]-DSA from deuterated water at the SDS micelle interface was measured by deuterium electron spin echo modulation. The distances increased from 5-DSA to 12-DSA and then decreased for 16-DSA. The interpretation of the DSR line width trend is supported by the deuterium modulation depth trend. 28 refs., 5 figs., 2 tabs.

  9. Characterization of predominantly hydrophobic poly(styrene)-poly(ethylene oxide) copolymers at air/water and cyclohexane/water interfaces

    SciTech Connect

    Gragson, D.E.; Jensen, J.M.; Baker, S.M.

    1999-09-14

    Interfacial tension measurements are employed to explore the spreading behavior of predominantly hydrophobic poly(styrene)--poly(ethylene oxide), PS-PEO, diblock copolymers at air/water and cyclohexane/water interfaces. Two copolymers with 7%- and 15.5%-PEO are examined in this study. The former is expected to have a PS block limiting area in air roughly equal to the limiting PEO pancake area, whereas the latter is expected to have a limiting PS block area in air approximately 3 times smaller than the limiting PEO pancake area. At the air/water interface, the 7%-PEO copolymer does not spread well, which is attributed to interference from the hydrophobic PS block. In contrast, the 7%-PEO copolymer spreads well at the cyclohexane/water interface, producing an isotherm with a terminating mean molecular area 3 times smaller than that obtained at the air/water interface. The 15.5%-PEO copolymer spreads well at both the air/water ad cyclohexane/water interfaces due to less interference from the smaller hydrophobic PS block. These observations are compared to compression isotherms, and the results are discussed in terms of the solvating nature of the adjacent cyclohexane phase for the PS block.

  10. Phase Behavior and Ionic Conductivity of Concentrated Solutions of Polystyrene-Poly(ethylene oxide) Diblock Copolymers in an Ionic Liquid

    SciTech Connect

    Simone, Peter M.; Lodge, Timothy P.

    2010-03-16

    Concentrated solutions of poly(styrene-b-ethylene oxide) (PS-PEO) diblock copolymers were prepared using the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [EMI][TFSI] as the solvent. The self-assembled microstructures adopted by the copolymer solutions have been characterized using small-angle X-ray scattering. Lyotropic mesophase transitions were observed, with a progression from hexagonally packed cylinders of PEO, to lamellae, to hexagonally packed cylinders of PS upon increasing [EMI][TFSI] content. The change in lamellar domain spacing with ionic liquid concentration was found to be comparable to that reported for other block copolymers in strongly selective solvents. The ionic conductivity of the concentrated PS-PEO/[EMI][TFSI] solutions was measured via impedance spectroscopy, and ranged from 1 x 10{sup -7} to 1 x 10{sup -3} S/cm at temperatures from 25-100 C. Additionally, the ionic conductivity of the solutions was found to increase with both ionic liquid concentration and molecular weight of the PEO blocks. The ionic conductivity of PEO homopolymer/[EMI][TFSI] solutions was also measured in order to compare the conductivity of the PS-PEO solutions to the expected limit for a lamellar sample with randomly oriented microstructure grains.

  11. Lyotropic Phase Behavior of Poly(ethylene oxide)-Poly(butadiene) Diblock Copolymers: Evolution of the Random Network Morphology

    SciTech Connect

    Jain, Sumeet; Dyrdahl, Mitchell H.E.; Gong, Xiaobo; Scriven, L.E.; Bates, Frank S.

    2008-10-24

    The phase behavior of poly(ethylene oxide)-poly(butadiene) (PEO-PB) diblock copolymers mixed with water was studied using small-angle X-ray scattering (SAXS), cryogenic scanning electron microscopy (cryo-SEM), cryogenic transmission electron microscopy (cryo-TEM), and dynamic mechanical spectroscopy. Two sets of diblocks were synthesized by adding different lengths of PEO to hydroxy terminated PB with degrees of polymerization N{sub PB} = 46 and 170. Two-component mixtures were investigated as a function of block composition and copolymer molecular weight, between 1 and 100 wt % polymer content. Melt phase behavior is consistent with established theory and known experimental behavior for diblock copolymers. Various lyotropic liquid crystalline structures, notably lamellae (L), hexagonally packed cylinders (H), and spheres (S) arranged on cubic (body-centered cubic, face-centered cubic) lattices, were documented as a function of water content. At the higher molecular weights (N{sub PB} = 170), a random network phase (N) was identified over a sizable portion of the phase portrait, located between hexagonally ordered cylinders and ordered lamellae. This new structure, along with branching of cylindrical micelles in the dilute limit, bear a striking similarity to experimentally observed and theoretically predicted phase behavior in certain ternary water/oil/surfactant systems. These findings demonstrate that block copolymer surfactants are characterized by at least four structural building blocks -- spheres, cylinders, bilayers, and branched cylinders -- above a threshold molecular weight.

  12. Poly(ethylene oxide)-Assisted Macromolecular Self-Assembly of Lignin in ABS Matrix for Sustainable Composite Applications

    DOE PAGESBeta

    Akato, Kokouvi M.; Tran, Chau D.; Chen, Jihua; Naskar, Amit K.

    2015-11-05

    Here we report the compatibilization of biomass-derived lignin polymer in acrylonitrile butadiene styrene (ABS) thermoplastic matrix without loss of mechanical properties via poly(ethylene oxide) (PEO)-mediated macromolecular self-assembly. ABS was blended with lignin in different concentrations, and blends with 10 wt % PEO (relative to lignin) were prepared. The relative tensile strength improved slightly at low lignin content but diminished rapidly as the lignin content was increased. However, the inclusion of PEO as an interfacial adhesion promoter helped avoid deleterious effects. Dynamic mechanical analysis showed that PEO plasticized the hard phase and thus lowered the activation energy (Ea) for its relaxationmore » but caused stiffening of the soft phase and increased its Ea. Microscopy revealed that incorporating lignin in ABS led to the statistical dispersion of discrete lignin domains (300–1000 nm) which, after PEO addition, were reduced to smaller interconnected particles (200–500 nm). The lignin-extended partially renewable ABS resins showed shear-thinning behavior and reduced viscosity compared to neat ABS. The preferred lignin-loaded compositions reinforced with 20 vol % chopped carbon fibers exhibited mechanical performances (77–80 MPa) equivalent to those of reinforced ABS materials reportedly used in 3D printing applications. In conclusion, this approach could lower the cost of ABS while reducing its carbon footprint.« less

  13. Polymer-Ion Interaction Weakens the Strain-Rate Dependence of Extension-Induced Crystallization for Poly(ethylene oxide).

    PubMed

    Hu, Tingting; Tian, Nan; Ali, Sarmad; Wang, Zhen; Chang, Jiarui; Huang, Ningdong; Li, Liangbin

    2016-03-01

    The crystallization of poly(ethylene oxide) (PEO)-sodium iodine (NaI) composites is investigated by differential scanning calorimetry (DSC), extensional rheology, and in situ small-angle X-ray scattering (SAXS) with the aim of demonstrating versatile roles played by polymer-ion interactions. In the isothermal quiescent crystallization process, a decrease in the crystal growth rate is observed for PEO-NaI and is attributed to slow chain movement caused by the coordination between cations and polymer. In situ SAXS on extensional flow-induced crystallization (FIC) exhibits enhanced kinetics and orientation for both PEO and PEO-NaI with increasing strain rate. However, an overall weaker strain-rate dependence of FIC is observed for PEO-NaI, which can be interpreted as a synergistic consequence of promoted nucleation under flow and impeded crystal growth by polymer-ion interaction. A possible microscopic mechanism is proposed to account for the experimental observation based on the formation of transient cross-linking points in PEO-NaI and their influence on the entanglement network of polymer under various flow fields. The disclosed strain-rate dependence and various ion effects on the behavior of PEO-salt composites contribute to a comprehensive understanding of polymer-ion solid polyelectrolytes. PMID:26822166

  14. Enhanced luminescence properties of highly threaded conjugated polyelectrolytes with potassium counter-ions upon blending with poly(ethylene oxide)

    NASA Astrophysics Data System (ADS)

    Latini, Gianluca; Winroth, Gustaf; Brovelli, Sergio; McDonnell, Shane O.; Anderson, Harry L.; Mativetsky, Jeffrey M.; Samorı, Paolo; Cacialli, Franco

    2010-06-01

    The photophysics and electroluminescence (EL) of thin films of unthreaded and cyclodextrin-encapsulated poly(4,4'-diphenylenevinylene) (PDV) with potassium countercations, blended with poly(ethylene oxide) (PEO) are investigated as a function of the PEO concentration. We show that three main factors contribute to increasing the photoluminescence (PL) quantum efficiency as a result of suppressed intermolecular interactions, namely: the high degree of encapsulation of the polyrotaxanes, the relatively large countercation (e.g., compared to lithium), and the complexation of the rotaxanes with PEO. By facilitating cationic transport to the negative electrodes, PEO also leads to devices with enhanced electron injection and improved charge balance, whose operation therefore resembles that of "virtually unipolar" light-emitting electrochemical cells. This effect, together with the enhanced PL efficiency, leads to higher EL efficiency for both polyrotaxanes and unthreaded polymers, upon addition of the PEO. We show that the concurrent exploitation of the various strategies above lead to an overall EL efficiency that is approximately twice the value previously reported for Li-based PDV. A blueshift of the EL spectrum during the devices turn-on is also reported and analyzed in terms of interference and doping effects.

  15. SPECT/CT Imaging of Pluronic Nanocarriers with Varying Poly(ethylene oxide) Block Length and Aggregation State.

    PubMed

    Arranja, Alexandra; Ivashchenko, Oleksandra; Denkova, Antonia G; Morawska, Karolina; van Vlierberghe, Sandra; Dubruel, Peter; Waton, Gilles; Beekman, Freek J; Schosseler, François; Mendes, Eduardo

    2016-03-01

    Optimal biodistribution and prolonged circulation of nanocarriers improve diagnostic and therapeutic effects of enhanced permeability and retention-based nanomedicines. Despite extensive use of Pluronics in polymer-based pharmaceuticals, the influence of different poly(ethylene oxide) (PEO) block length and aggregation state on the biodistribution of the carriers is rather unexplored. In this work, we studied these effects by evaluating the biodistribution of Pluronic unimers and cross-linked micelles with different PEO block size. In vivo biodistribution of (111)In-radiolabeled Pluronic nanocarriers was investigated in healthy mice using single photon emission computed tomography. All carriers show fast uptake in the organs from the reticuloendothelial system followed by a steady elimination through the hepatobiliary tract and renal filtration. The PEO block length affects the initial renal clearance of the compounds and the overall liver uptake. The aggregation state influences the long-term accumulation of the nanocarriers in the liver. We showed that the circulation time and elimination pathways can be tuned by varying the physicochemical properties of Pluronic copolymers. Our results can be beneficial for the design of future Pluronic-based nanomedicines. PMID:26883169

  16. Enhanced Catalytic Activities of NiPt Truncated Octahedral Nanoparticles toward Ethylene Glycol Oxidation and Oxygen Reduction in Alkaline Electrolyte.

    PubMed

    Xia, Tianyu; Liu, Jialong; Wang, Shouguo; Wang, Chao; Sun, Young; Gu, Lin; Wang, Rongming

    2016-05-01

    The high cost and poor durability of Pt nanoparticles (NPs) are great limits for the proton exchange membrane fuel cells (PEMFCs) from being scaled-up for commercial applications. Pt-based bimetallic NPs together with a uniform distribution can effectively reduce the usage of expensive Pt while increasing poison resistance of intermediates. In this work, a simple one-pot method was used to successfully synthesize ultrafine (about 7.5 nm) uniform NiPt truncated octahedral nanoparticles (TONPs) in dimethylformamid (DMF) without any seeds or templates. The as-prepared NiPt TONPs with Pt-rich surfaces exhibit greatly improved catalytic activities together with good tolerance and better stability for ethylene glycol oxidation reaction (EGOR) and oxygen reduction reaction (ORR) in comparison with NiPt NPs and commercial Pt/C catalysts in alkaline electrolyte. For example, the value of mass and specific activities for EGOR are 23.2 and 17.6 times higher comparing with those of commercial Pt/C, respectively. Our results demonstrate that the dramatic enhancement is mainly attributed to Pt-rich surface, larger specific surface area, together with coupling between Ni and Pt atoms. This developed method provides a promising pathway for simple preparation of highly efficient electrocatalysts for PEMFCs in the near future. PMID:27093304

  17. Mixed micellar nanoparticle of amphotericin B and poly styrene-block-poly ethylene oxide reduces nephrotoxicity but retains antifungal activity.

    PubMed

    Han, Kun; Miah, M A Jalil; Shanmugam, Srinivasan; Yong, Chul Soon; Choi, Han-Gon; Kim, Jung Ae; Yoo, Bong Kyu

    2007-10-01

    Mixed micellar nanoparticle consisting of amphotericin B (AmB) and poly styrene-block-poly ethylene oxide (PS-block-PEO) was prepared by high pressure homogenizer. Nephrotoxicity of the nanoparticle was investigated along with antifungal activity and self-aggregation status of the drug in the nanoparticle. Nephrotoxicity was markedly reduced when AmB was intravenously administered to rats as mixed micellar nanoparticle with PS-block-PEO in terms of transmission electron microscopy of tubular cells and creatinine clearance. Antifungal activity of AmB was not altered when the drug was in the form of mixed micellar nanoparticle compared to both conventional formulation and AmB micelle treated by same procedure without PS-block-PEO. Self-aggregation status of AmB molecules revealed monomeric in the mixed micellar nanoparticle with PS-block-PEO up to the therapeutic level of the drug (1-3 mM). The reduced nephrotoxicity of AmB in mixed micellar nanoparticle may be associated with the existence of the drug as monomeric form in the nanoparticle. Based on our result, formulation of AmB as mixed micellar nanoparticle with PS-block-PEO may be a promising alternative for the treatment of fungal diseases in patients who are at risk of renal dysfunction. PMID:18038914

  18. A bifunctional poly(ethylene glycol) silane immobilized on metallic oxide-based nanoparticles for conjugation with cell targeting agents

    SciTech Connect

    Kohler, Nathan J.; Fryxell, Glen E.; Zhang, Miqin

    2004-06-16

    A trifluoroethylester-terminal poly (ethylene glycol) (PEG) silane was synthesized and self-assembled on iron oxide nanoparticles. The nanoparticle system thus prepared has the flexibility to conjugate with cell targeting agents having either carboxylic and amine terminal groups for a number of biomedical applications, including magnetic resonance imaging (MRI) and controlled drug delivery. The trifluoroethylester silane was synthesized by modifying a PEG diacid to form the corresponding bistrifluoroethylester (TFEE), followed by a reaction with 3-aminopropyltriethoxysilane (APS). The APS coupled with PEG chains confers the stability of PEG self-assembled monolayers (SAMs) and increases the PEG packing density on nanoparticles by establishing hydrogen bonding between the carbonyl and amine groups present within the monolayer structure. The success of the synthesis of the PEG TEFE silane was confirmed with 1H NMR and Fourier transform infrared spectroscopy (FTIR). The conjugating flexibility of the PEG TEFE was demonstrated with folic acid having carboxylic acid groups and amine terminal groups respectively and confirmed by FTIR. TEM analysis showed the dispersion of nanoparticles before and after they were coated with PEG and folic acid.

  19. Polystyrene-poly(ethylene oxide) diblock copolymer: the effect of polystyrene and spreading concentration at the air/water interface.

    PubMed

    Glagola, Cameron P; Miceli, Lia M; Milchak, Marissa A; Halle, Emily H; Logan, Jennifer L

    2012-03-20

    Polystyrene-block-poly(ethylene oxide) (PS-PEO) is an amphiphilic diblock copolymer that undergoes microphase separation when spread at the air/water interface, forming nanosized domains. In this study, we investigate the impact of PS by examining a series of PS-PEO samples containing constant PEO (~17,000 g·mol(-1)) and variable PS (from 3600 to 200,000 g·mol(-1)) through isothermal characterization and atomic force microscopy (AFM). The polymers separated into two categories: predominantly hydrophobic and predominantly hydrophilic with a weight percent of PEO of ~20% providing the boundary between the two. AFM results indicated that predominantly hydrophilic PS-PEO forms dots while more hydrophobic samples yield a mixture of dots and spaghetti with continent-like structures appearing at ~7% PEO or less. These structures reflect a blend of polymer spreading, entanglement, and vitrification as the solvent evaporates. Changing the spreading concentration provides insight into this process with higher concentrations representing earlier kinetic stages and lower concentrations demonstrating later ones. Comparison of isothermal results and AFM analysis shows how polymer behavior at the air/water interface correlates with the observed nanostructures. Understanding the impact of polymer composition and spreading concentration is significant in leading to greater control over the nanostructures obtained through PS-PEO self-assembly and their eventual application as polymer templates. PMID:22339480

  20. Surfactant-assisted intercalation of high molecular weight poly(ethylene oxide) into vanadyl phosphate di-hydrate

    SciTech Connect

    Ferreira, Joao Paulo L.; Oliveira, Herenilton P.

    2012-03-15

    Graphical abstract: CuK{sub {alpha}} X-ray diffraction patterns of the VOPO{sub 4}/PEO (A) e VOPO{sub 4}/CTA (B) and VOPO{sub 4}/CTA/PEO (C). Highlights: Black-Right-Pointing-Pointer VOPO{sub 4}/PEO has been synthesized by using CTAB, thereby improving PEO intercalation. Black-Right-Pointing-Pointer The d-spacing increase from 1.30 nm (VOPO{sub 4}/PEO) to 2.94 nm (VOPO{sub 4}/CTA/PEO). Black-Right-Pointing-Pointer This strategy was viable for intercalation of PEO with high molecular weight. -- Abstract: A high molecular weight poly(ethylene oxide)/layered vanadyl phosphate di-hydrate intercalation compound was synthesized via the surfactant-assisted approach. Results confirmed that surfactant molecules were replaced with the polymer, while the lamellar structure of the matrix was retained, and that the material presents high specific surface area. In addition, intercalation produced a more thermally stable polymer as evidenced by thermal analysis.

  1. Adsorption energies of poly(ethylene oxide)-based surfactants and nanoparticles on an air-water surface.

    PubMed

    Zell, Zachary A; Isa, Lucio; Ilg, Patrick; Leal, L Gary; Squires, Todd M

    2014-01-14

    The self-assembly of polymer-based surfactants and nanoparticles on fluid-fluid interfaces is central to many applications, including dispersion stabilization, creation of novel 2D materials, and surface patterning. Very often these processes involve compressing interfacial monolayers of particles or polymers to obtain a desired material microstructure. At high surface pressures, however, even highly interfacially active objects can desorb from the interface. Methods of directly measuring the energy which keeps the polymer or particles bound to the interface (adsorption/desorption energies) are therefore of high interest for these processes. Moreover, though a geometric description linking adsorption energy and wetting properties through the definition of a contact angle can be established for rigid nano- or microparticles, such a description breaks down for deformable or aggregating objects. Here, we demonstrate a technique to quantify desorption energies directly, by comparing surface pressure-density compression measurements using a Wilhelmy plate and a custom-microfabricated deflection tensiometer. We focus on poly(ethylene oxide)-based polymers and nanoparticles. For PEO-based homo- and copolymers, the adsorption energy of PEO chains scales linearly with molecular weight and can be tuned by changing the subphase composition. Moreover, the desorption surface pressure of PEO-stabilized nanoparticles corresponds to the saturation surface pressure for spontaneously adsorbed monolayers, yielding trapping energies of ∼10(3) k(B)T. PMID:24328531

  2. Molecular dynamics simulation of polymer electrolytes based on poly(ethylene oxide) and ionic liquids. II. Dynamical properties

    NASA Astrophysics Data System (ADS)

    Costa, Luciano T.; Ribeiro, Mauro C. C.

    2007-10-01

    Dynamical properties of polymer electrolytes based on poly(ethylene oxide) (PEO) and ionic liquids of 1-alkyl-3-methylimidazolium cations were calculated by molecular dynamics simulations with previously proposed models [L. T. Costa and M. C. Ribeiro, J. Chem. Phys. 124, 184902 (2006)]. The effect of changing the ionic liquid concentration, temperature, and the 1-alkyl-chain lengths, [1,3-dimethylimidazolium]PF6 and [1-butyl-3-methylimidazolium]PF6 ([dmim]PF6 and [bmim]PF6), was investigated. Cation diffusion coefficient is higher than those of anion and oxygen atoms of PEO chains. Ionic mobility in PEO /[bmim]PF6 is higher than in PEO /[dmim]PF6, so that the ionic conductivity κ of the former is approximately ten times larger than the latter. The ratio between κ and its estimate from the Nernst-Einstein equation κ /κNE, which is inversely proportional to the strength of ion pairs, is higher in ionic liquid polymer electrolytes than in polymer electrolytes based on inorganic salts with Li+ cations. Calculated time correlation functions corroborate previous evidence from the analysis of equilibrium structure that the ion pairs in ionic liquid polymer electrolytes are relatively weak. Structural relaxation at distinct spatial scales is revealed by the calculation of the intermediate scattering function at different wavevectors. These data are reproduced with stretched exponential functions, so that temperature and wavevector dependences of best fit parameters can be compared with corresponding results for polymer electrolytes containing simpler ions.

  3. Nuclear magnetic resonance investigation of dynamics in poly(ethylene oxide)-based lithium polyether-ester-sulfonate ionomers

    DOE PAGESBeta

    Roach, David J.; Dou, Shichen; Colby, Ralph H.; Mueller, Karl T.

    2012-01-06

    Nuclear magnetic resonance (NMR) spectroscopy has been utilized to investigate the dynamics of poly(ethylene oxide)-based lithium sulfonate ionomer samples that have low glass transition temperatures. 1H and 7Li spin-lattice relaxation times (T1) of the bulk polymer and lithium ions, respectively, were measured and analyzed in samples with a range of ion contents. The temperature dependence of T1 values along with the presence of minima in T1 as a function of temperature enabled correlation times and activation energies to be obtained for both the segmental motion of the polymer backbone and the hopping motion of lithium cations. Similar activation energies formore » motion of both the polymer and lithium ions in the samples with lower ion content indicate that the polymer segmental motion and lithium ion hopping motion are correlated in these samples, even though their respective correlation times differ significantly. A divergent trend is observed for correlation times and activation energies of the highest ion content sample with 100% lithium sulfonation due to the presence of ionic aggregation. Details of the polymer and cation dynamics on the nanosecond timescale are discussed and complement the findings of X-ray scattering and Quasi Elastic Neutron Scattering experiments.« less

  4. Preparation and interfacial properties of a novel biodegradable polymer surfactant: poly(ethylene oxide monooleate-block-DL-lactide).

    PubMed

    Nishino, Satoru; Kitamura, Yoshiro; Kishida, Akio; Yoshizawa, Hidekazu

    2005-11-01

    In this paper, we report a novel synthesis of poly(ethylene oxide monooleate-block-DL-lactide) (MOPEO-PLA) in the presence of stannous 2-ethylhexanoate catalyst. By utilizing the surfactant property and the reactive double bond of the amphiphilic MOPEO-PLA, various characteristics of PLA microspheres, such as surface and internal structure, surface morphology, release property, and so on, may potentially be controlled. MOPEO-PLA was found to be hydrophobic enough to prevent loss by dissolution into aqueous solution, which is often a problem for MOPEO. Furthermore, the interfacial tension measurements of a MOPEO-PLA/toluene/water system revealed that MOPEO-PLA had a good surface activity almost equal to that of MOPEO. The MOPEO-PLA/PLA blend films were prepared by solvent casting on a water layer. Contact-angle measurements of MOPEO-PLA/PLA blend films confirmed that the hydrophilic PEO segments were selectivity accumulated at the oil/water interface. Moreover, the surface free energy on the 'water side' of the MOPEO-PLA/PLA blend films was increased because of the increase in polar components as a result of the ether bonds of the PEO segments. Schematic illustration of the adsorption property of a) MOPEO-PLA with a high-molecular-weight PLA segment and b) MOPEO-PLA with a low-molecular-weight PLA segment at an ethyl acetate/water interface. PMID:16245272

  5. Poly(ethylene oxide)-Assisted Macromolecular Self-Assembly of Lignin in ABS Matrix for Sustainable Composite Applications

    SciTech Connect

    Akato, Kokouvi M.; Tran, Chau D.; Chen, Jihua; Naskar, Amit K.

    2015-11-05

    Here we report the compatibilization of biomass-derived lignin polymer in acrylonitrile butadiene styrene (ABS) thermoplastic matrix without loss of mechanical properties via poly(ethylene oxide) (PEO)-mediated macromolecular self-assembly. ABS was blended with lignin in different concentrations, and blends with 10 wt % PEO (relative to lignin) were prepared. The relative tensile strength improved slightly at low lignin content but diminished rapidly as the lignin content was increased. However, the inclusion of PEO as an interfacial adhesion promoter helped avoid deleterious effects. Dynamic mechanical analysis showed that PEO plasticized the hard phase and thus lowered the activation energy (Ea) for its relaxation but caused stiffening of the soft phase and increased its Ea. Microscopy revealed that incorporating lignin in ABS led to the statistical dispersion of discrete lignin domains (300–1000 nm) which, after PEO addition, were reduced to smaller interconnected particles (200–500 nm). The lignin-extended partially renewable ABS resins showed shear-thinning behavior and reduced viscosity compared to neat ABS. The preferred lignin-loaded compositions reinforced with 20 vol % chopped carbon fibers exhibited mechanical performances (77–80 MPa) equivalent to those of reinforced ABS materials reportedly used in 3D printing applications. In conclusion, this approach could lower the cost of ABS while reducing its carbon footprint.

  6. Nuclear magnetic resonance investigation of dynamics in poly(ethylene oxide)-based lithium polyether-ester-sulfonate ionomers

    NASA Astrophysics Data System (ADS)

    Roach, David J.; Dou, Shichen; Colby, Ralph H.; Mueller, Karl T.

    2012-01-01

    Nuclear magnetic resonance spectroscopy has been utilized to investigate the dynamics of poly(ethylene oxide)-based lithium sulfonate ionomer samples that have low glass transition temperatures. 1H and 7Li spin-lattice relaxation times (T1) of the bulk polymer and lithium ions, respectively, were measured and analyzed in samples with a range of ion contents. The temperature dependence of T1 values along with the presence of minima in T1 as a function of temperature enabled correlation times and activation energies to be obtained for both the segmental motion of the polymer backbone and the hopping motion of lithium cations. Similar activation energies for motion of both the polymer and lithium ions in the samples with lower ion content indicate that the polymer segmental motion and lithium ion hopping motion are correlated in these samples, even though lithium hopping is about ten times slower than the segmental motion. A divergent trend is observed for correlation times and activation energies of the highest ion content sample with 100% lithium sulfonation due to the presence of ionic aggregation. Details of the polymer and cation dynamics on the nanosecond timescale are discussed and complement the findings of X-ray scattering and quasi-elastic neutron scattering experiments.

  7. Charge transport and glassy dynamics of poly(ethylene oxide)-based single-ion conductors under geometrical confinement

    NASA Astrophysics Data System (ADS)

    Runt, James; Iacob, Ciprian

    2015-03-01

    Segmental and local dynamics as well as charge transport are investigated in a series of poly(ethylene oxide)-based single-ion conductors (ionomers) with varying counterions (Li +, Na +) confined in uni-directional nanoporous silica membranes. The dynamics are explored over a wide frequency and temperature range by broadband dielectric relaxation spectroscopy. Slowing of segmental dynamics and a decrease in dc conductivity (strongly coupled with segmental relaxation) of the confined ionomers are associated with surface effects - resulting from interfacial hydrogen bonding between the host nanoporous silica membrane and the guest ionomers. These effects are significantly reduced or eliminated upon pore surface modification through silanization. The primary transport properties for the confined ionomers decrease by about one decade compared to the bulk ionomer. A model assuming reduced mobility of an adsorbed layer at the pore wall/ionomer interface is shown to provide a quantitative explanation for the decrease in effective transport quantities in non-silanized porous silica membranes. Additionally, the effect of confinement on ion aggregation in ionomers by using X-ray scattering will also be discussed. Supported by the National Science Foundation, Polymers Program.

  8. Nuclear Magnetic Resonance Investigation of Dynamics in Poly(Ethylene Oxide) Based Lithium Polyether-ester-sulfonate Ionomers

    SciTech Connect

    Roach, David J.; Dou, Shichen; Colby, Ralph H.; Mueller, Karl T.

    2012-01-07

    Nuclear magnetic resonance (NMR) spectroscopy has been utilized to investigate the dynamics of poly(ethylene oxide)-based lithium sulfonate ionomer samples that have low glass transition temperatures. 1H and 7Li spin-lattice relaxation times (T1) of the bulk polymer and lithium ions, respectively, were analyzed in samples with a range of ion contents. The temperature dependence of T1 values along with the presence of minima in T1 enabled correlation times and activation energies to be obtained for both the segmental motion of the polymer backbone and the hopping motion of lithium cations. Similar activation energies of both the polymer and lithium ions in the lower ion content samples indicate that the polymer segmental motion and lithium ion hopping motion are correlated even though their respective correlation times differ significantly. A divergent trend is observed for correlation times and activation energies of the highest ion content sample due to the presence of ionic aggregation. Details about the polymer and cation dynamics on the nanosecond timescale are discussed and complement the findings of X-ray scattering and Quasi Elastic Neutron Scattering experiments.

  9. Nuclear magnetic resonance investigation of dynamics in poly(ethylene oxide)-based lithium polyether-ester-sulfonate ionomers

    SciTech Connect

    Roach, David J.; Dou, Shichen; Colby, Ralph H.; Mueller, Karl T.

    2012-01-06

    Nuclear magnetic resonance (NMR) spectroscopy has been utilized to investigate the dynamics of poly(ethylene oxide)-based lithium sulfonate ionomer samples that have low glass transition temperatures. 1H and 7Li spin-lattice relaxation times (T1) of the bulk polymer and lithium ions, respectively, were measured and analyzed in samples with a range of ion contents. The temperature dependence of T1 values along with the presence of minima in T1 as a function of temperature enabled correlation times and activation energies to be obtained for both the segmental motion of the polymer backbone and the hopping motion of lithium cations. Similar activation energies for motion of both the polymer and lithium ions in the samples with lower ion content indicate that the polymer segmental motion and lithium ion hopping motion are correlated in these samples, even though their respective correlation times differ significantly. A divergent trend is observed for correlation times and activation energies of the highest ion content sample with 100% lithium sulfonation due to the presence of ionic aggregation. Details of the polymer and cation dynamics on the nanosecond timescale are discussed and complement the findings of X-ray scattering and Quasi Elastic Neutron Scattering experiments.

  10. Dodecagonal Quasicrystalline Morphology in a Poly(styrene-b-isoprene-b-styrene-b-ethylene oxide) Tetrablock Terpolymer

    SciTech Connect

    Zhang, Jingwen; Bates, Frank S.

    2012-10-26

    A dodecagonal quasicrystalline (QC) morphology is identified in a poly(styrene-b-isoprene-b-styrene-b-ethylene oxide) (SISO) tetrablock terpolymer based on evidence provided by transmission electron microscopy (TEM), small-angle X-ray scattering, and dynamic mechanical spectroscopy measurements. The QC state occurs at temperatures between those associated with simple hexagonal order (HEX) and the {sigma}-phase (P4{sub 2}/mnm), T{sub HEX} < T{sub QC} < T{sub {sigma}} < T{sub ODT}, where T{sub ODT} is the order-disorder transition temperature. All three morphologies are formed from spherical domains containing an O core surrounded by a shell of S that screens unfavorable segment-segment interactions with an I-rich matrix. TEM analysis reveals a QC morphology with 12-fold rotational symmetry but devoid of long-range translational order, along with locally coordinated structures consistent with dodecagonal quasicrystalline approximants. The SISO molecular architecture decouples control over the domain shape and interdomain interactions, leading to a multiplicity of packing symmetries.

  11. Synthesis and Gelation Characteristics of Photo-Crosslinkable Star Poly(ethylene oxide-co-lactide-glycolide acrylate) Macromonomers

    PubMed Central

    Moeinzadeh, Seyedsina; Khorasani, Saied Nouri; Ma, Junyu; He, Xuezhong; Jabbari, Esmaiel

    2011-01-01

    Viability of encapsulated cells in situ crosslinkable macromonomers depends strongly on the minimum concentration of polymerization initiators and monomers required for gelation. Novel 4-arm poly(ethylene oxide-co-lactide-glycolide acrylate) (SPELGA) macromonomers were synthesized and characterized with respect to gelation, sol fraction, degradation, and swelling in aqueous solution. SPELGA macromonomers were crosslinked in the absence of N-vinyl-2-pyrrolidone (NVP) monomer to produce a hydrogel network with a shear modulus of 27±4 kPa. The shear modulus of the gels increased by 170-fold as the macromonomer concentration was increased from 10 to 25 wt%. Sol fraction ranged between 8–18%. Addition of only 0.4 mol% NVP to the polymerization mixture increased modulus by 2.2-fold from 27±4 (no NVP) to 60±10 kPa. The higher modulus was attributed to the dilution effect of polymer chains in the sol, by delaying the onset of diffusion-controlled reaction, and cross-propagation of the growing chains with network-bound SPELGA acrylates. Degradation of SPELGA gels depended on water content and density of hydrolytically degradable ester groups. PMID:21927508

  12. An in vitro study of bare and poly(ethylene glycol)-co-fumarate-coated superparamagnetic iron oxide nanoparticles: a new toxicity identification procedure

    NASA Astrophysics Data System (ADS)

    Mahmoudi, Morteza; Simchi, Abdolreza; Imani, Mohammad; Milani, Abbas S.; Stroeve, Pieter

    2009-06-01

    As the use of superparamagnetic iron oxide nanoparticles (SPION) in biomedical applications increases (e.g. for targeting drug delivery and imaging), patients are likely to be exposed to products containing SPION. Despite their high biomedical importance, toxicity data for SPION are limited to date. The aim of this study is to investigate the cytotoxicity of SPION and its ability to change cell medium components. Bare and poly(ethylene glycol)-co-fumarate (PEGF)-coated SPION with narrow size distributions were synthesized. The particles were prepared by co-precipitation using ferric and ferrous salts with a molar Fe3+/Fe2+ ratio of 2. Dulbecco's modified Eagle's medium (DMEM) and primary mouse fibroblast (L929) cell lines were exposed to the SPION. Variation of cell medium components and cytotoxicity due to the interactions with nanoparticles were analyzed using ultraviolet and visible spectroscopy (UV/vis) and the 3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazolium bromide (MTT) assay methods, respectively. The toxicity amount has been traditionally identified by changes in pH and composition in cells and DMEM due to the tendency of SPION to adsorb proteins, vitamins, amino acids and ions. For in vitro toxicity assessments, a new surface passivation procedure is proposed which can yield more reliable quantitative results. It is shown that a more reliable way of identifying cytotoxicity for in vitro assessments is to use particles with saturated surfaces via interactions with DMEM before usage.

  13. CO2-Free Power Generation on an Iron Group Nanoalloy Catalyst via Selective Oxidation of Ethylene Glycol to Oxalic Acid in Alkaline Media

    PubMed Central

    Matsumoto, Takeshi; Sadakiyo, Masaaki; Ooi, Mei Lee; Kitano, Sho; Yamamoto, Tomokazu; Matsumura, Syo; Kato, Kenichi; Takeguchi, Tatsuya; Yamauchi, Miho

    2014-01-01

    An Fe group ternary nanoalloy (NA) catalyst enabled selective electrocatalysis towards CO2-free power generation from highly deliverable ethylene glycol (EG). A solid-solution-type FeCoNi NA catalyst supported on carbon was prepared by a two-step reduction method. High-resolution electron microscopy techniques identified atomic-level mixing of constituent elements in the nanoalloy. We examined the distribution of oxidised species, including CO2, produced on the FeCoNi nanoalloy catalyst in the EG electrooxidation under alkaline conditions. The FeCoNi nanoalloy catalyst exhibited the highest selectivities toward the formation of C2 products and to oxalic acid, i.e., 99 and 60%, respectively, at 0.4 V vs. the reversible hydrogen electrode (RHE), without CO2 generation. We successfully generated power by a direct EG alkaline fuel cell employing the FeCoNi nanoalloy catalyst and a solid-oxide electrolyte with oxygen reduction ability, i.e., a completely precious-metal-free system. PMID:25004118

  14. Effect of low-temperature ethylene oxide and electron beam sterilization on the in vitro and in vivo function of reconstituted extracellular matrix-derived scaffolds.

    PubMed

    Proffen, Benedikt L; Perrone, Gabriel S; Fleming, Braden C; Sieker, Jakob T; Kramer, Joshua; Hawes, Michael L; Murray, Martha M

    2015-10-01

    Reconstituted extracellular matrix (ECM)-derived scaffolds are commonly utilized in preclinical tissue engineering studies as delivery vehicles for cells and growth factors. Translation into clinical use requires identifying a sterilization method that effectively removes bacteria but does not harm scaffold function. To determine effectiveness of sterilization and impact on ECM scaffold integrity and function, low-temperature ethylene oxide and 15 kGy electron beam irradiation techniques were evaluated. Scaffold sterility was assessed in accordance to United States Pharmacopeia Chapter 71. Scaffold matrix degradation was determined in vitro using enzymatic resistance tests and gel electrophoresis. Scaffold mechanics including elastic modulus, yield stress and collapse modulus were tested. Lastly, 14 Yorkshire pigs underwent ACL transection and bio-enhanced ACL repair using sterilized scaffolds. Histologic response of ligament, synovium, and lymph nodes was compared at 4, 6, and 8 weeks. Ethylene oxide as well as electron beam irradiation yielded sterile scaffolds. Scaffold resistance to enzymatic digestion and protein integrity slightly decreased after electron beam irradiation while ethylene oxide altered scaffold matrix. Scaffold elastic modulus and yield stress were increased after electron beam treatment, while collapse modulus was increased after ethylene oxide treatment. No significant changes in ACL dimensions, in vivo scaffold resorption rate, or histologic response of synovium, ligament, and lymph nodes with either terminal sterilization technique were detectable. In conclusion, this study identifies two methods to terminally sterilize an ECM scaffold. In vitro scaffold properties were slightly changed without significantly influencing the biologic responses of the surrounding tissues in vivo. This is a critical step toward translating new tissue engineering strategies to clinical trials. PMID:26088294

  15. Identification of products from canthaxanthin oxidation.

    PubMed

    Mordi, Raphael C; Walton, John C

    2016-04-15

    Canthaxanthin is a carotenoid that lacks pro-vitamin A activity but is known to have antioxidant activity. The products of its oxidation in oxygen were found to be mainly substituted apo-carotenals and apo-carotenones. The product profile resembles that obtained in the oxidation of β-carotene, except that with canthaxanthin these products are the 4-oxo-β-apo-carotenals and 4-oxo-β-apo-carotenones. Epoxides and diepoxides were clearly identified from β-carotene oxidation but in contrast, with canthaxanthin, apart from 5,6-epoxy-canthaxanthin, which was detected at the early stage of oxidation and minor quantities of 5,6-epoxy-β-ionone and 5,6-epoxy-4-oxo-β-apo-11-carotenal, no other epoxides were detected. The identities of these products lead us to suggest that the mechanism of canthaxanthin oxidation bears significant similarity to that of β-carotene. PMID:26617024

  16. The use of poly(ethylene oxide) for the efficient stabilization of entrapped alpha-chymotrypsin in silicone elastomers: a chemometric study.

    PubMed

    Ragheb, Amro M; Hileman, Oliver E; Brook, Michael

    2005-12-01

    The enzyme alpha-chymotrypsin, a model for catalytic proteins, was entrapped in different silicone elastomers that were formed via the condensation-cure room temperature vulcanization (CC-RTV) of silanol terminated poly(dimethylsiloxane) with tetraethyl orthosilicate as a crosslinker, in the presence of different poly(ethylene oxide) oligomers that were functionalized with triethoxysilyl groups. The effects of various chemical factors on both the activity and entrapping efficiency of proteins (leaching) were studied using a 2-level fractional factorial design--a chemometrics approach. The factors studied include the concentration and chain length of poly(ethylene oxide), enzyme content, and crosslinker (TEOS) concentration. The study indicated that poly(ethylene oxide) can stabilize the entrapped alpha-chymotrypsin in silicone rubber: the specific activity can be maximized by incorporating a relatively high content of short chain, functional PEO. Increased enzyme concentration was found to adversely affect the specific activity. The effect of TEOS was found to be insignificant when PEO was present in the elastomer, however, it does affect the activity positively in the case of simple elastomers. PMID:15992922

  17. Complex Formation Between Lysozyme and Stabilized Micelles with a Mixed Poly(ethylene oxide)/Poly(acrylic acid) Shell.

    PubMed

    Karayianni, Maria; Gancheva, Valeria; Pispas, Stergios; Petrov, Petar

    2016-03-10

    The electrostatic complexation between lysozyme and stabilized polymeric micelles (SPMs) with a poly(acrylic acid) (PAA) or a mixed poly(ethylene oxide)/poly(acrylic acid) (PEO/PAA) shell (SPMs with a mixed shell, SPMMS) and a temperature-responsive poly(propylene oxide) (PPO) core was investigated by means of dynamic, static, and electrophoretic light scattering. The SPMs and different types of SPMMS used resulted from the self-assembly of PAA-PPO-PAA triblock copolymer chains, or PAA-PPO-PAA and PEO-PPO-PEO triblock copolymer chain mixtures (with varying chain lengths and molar ratios) in aqueous solutions at pH 10 and the subsequent cross-linking of their PPO cores via loading and photo-cross-linking of pentaerythritol tetraacrylate (PETA). The solution behavior, structure and properties of the formed complexes at pH 7 and 0.01 M ionic strength, were studied as a function of the protein concentration in the solution (the concentration of the stabilized micelles was kept constant) or equivalently the ratio of the two components. The complexation process and properties of the complexes proved to be dependent on the protein concentration, while of particular interest was the effect of the structure of the shell of the SPMs on the stability/solubility of the complexes. Finally, the fluorescence and mid infrared spectroscopic investigation of the structure of the complexed protein showed that, although a small stretching of the protein molecules occurred in some cases, no protein denaturation takes place upon complexation. PMID:26881445

  18. Lycopene oxidation product enhances gap junctional communication.

    PubMed

    Aust, O; Ale-Agha, N; Zhang, L; Wollersen, H; Sies, H; Stahl, W

    2003-10-01

    Carotenoids as well as their metabolites and oxidation products stimulate gap junctional communication (GJC) between cells, which is thought to be one of the protective mechanisms related to cancer-preventive activities of these compounds. Increased intake of lycopene by consumption of tomatoes or tomato products has been epidemiologically associated with a diminished risk of prostate cancer. Here, we report a stimulatory effect of a lycopene oxidation product on GJC in rat liver epithelial WB-F344 cells. The active compound was obtained by complete in vitro oxidation of lycopene with hydrogen peroxide/osmium tetroxide. For structural analysis high performance liquid chromatography, gas chromatography coupled with mass spectrometry, ultraviolet/visible-, and infrared spectrophotometry were applied. The biologically active oxidation product was identified as 2,7,11-trimethyl-tetradecahexaene-1,14-dial. The present data indicate a potential role of lycopene degradation products in cell signaling enhancing cell-to-cell communication via gap junctions. PMID:12909274

  19. 40 CFR 721.10375 - Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide, copolymer...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... reporting. (1) The chemical substance identified generically as hydroxypropyl methacrylate, reaction... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Hydroxypropyl methacrylate, reaction... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific...

  20. 40 CFR 721.10375 - Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide, copolymer...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... reporting. (1) The chemical substance identified generically as hydroxypropyl methacrylate, reaction... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Hydroxypropyl methacrylate, reaction... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific...

  1. 40 CFR 721.10375 - Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide, copolymer...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... reporting. (1) The chemical substance identified generically as hydroxypropyl methacrylate, reaction... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Hydroxypropyl methacrylate, reaction... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific...

  2. Degradation of ethylene glycol using Fenton's reagent and UV.

    PubMed

    McGinnis, B D; Adams, V D; Middlebrooks, E J

    2001-10-01

    Oxidation of ethylene glycol in aqueous solutions was found to occur with the addition of Fenton's reagent with further conversion observed upon UV irradiation. The pH range studied was 2.5-9.0 with initial H2O2 concentrations ranging from 100 to 1000 mg/l. Application of this method to airport storm-water could potentially result in reduction of chemical oxygen demand by conversion of ethylene glycol to oxalic and formic acids. Although the amount of H2O2 added follows the amount of ethylene glycol degraded, smaller H2O2 doses were associated with increases in the ratio of ethylene glycol removed per unit H2O2 added indicating the potential of pulsed doses or constant H2O2 feed systems. Ethylene glycol removal was enhanced by exposure to UV light after treatment with Fenton's reagent, with rates dependent on initial H2O2 concentration. In addition to ethylene glycol, the principle products of this reaction, oxalic and formic acids, have been shown to be mineralized in other HO generating systems presenting the potential for ethylene glycol mineralization in this system with increased HO* production. PMID:11572583

  3. A Data Base of Nutrient Use, Water Use, CO2 Exchange, and Ethylene Production by Soybeans in a Controlled Environment

    NASA Technical Reports Server (NTRS)

    Wheeler, R. M.; Mackowiak, C. L.; Peterson, B. V.; Sager, J. C.; Knott, W. M.; Berry, W. L.; Sharifi, M. R.

    1998-01-01

    A data set is given describing daily nutrient and water uptake, carbon dioxide (CO2) exchange, ethylene production, and carbon and nutrient partitioning from a 20 sq m stand of soybeans (Glycine max (L.) Merr. cv. McCall] for use in bioregenerative life support systems. Stand CO2 exchange rates were determined from nocturnal increases in CO2 (respiration) and morning drawdowns (net photosynthesis) to a set point of 1000 micromol/ mol each day (i.e., a closed system approach). Atmospheric samples were analyzed throughout growth for ethylene using gas chromatography with photoionization detection (GC/PH)). Water use was monitored by condensate production from the humidity control system, as well as water uptake from the nutrient solution reservoirs each day. Nutrient uptake data were determined from daily additions of stock solution and acid to maintain an EC of 0.12 S/m and pH of 5.8. Dry mass yields of seeds, pods (without seeds), leaves, stems, and roots are provided, as well as elemental and proximate nutritional compositions of the tissues. A methods section is included to qualify any assumptions that might be required for the use of the data in plant growth models, along with a daily event calendar documenting set point adjustments and the occasional equipment or sensor failure.

  4. Reversible subacute ethylene glycol monomethyl ether toxicity associated with microfilm production: a case report

    SciTech Connect

    Cohen, R.

    1984-01-01

    The first reported case of a possible toxic effect of ethylene glycol monomethyl ether (EGME) exposure in the microfilm manufacturing industry is described. Reversible subjective central nervous system complaints and asymptomatic hematopoietic effects occurred following inhalation and skin exposure to EGME. Hematopoietic changes occurred at airborne levels which have been associated with reproductive and teratogenic effects in other studies. This finding leads to a recommendation for further research to determine whether or not hematopoietic medical surveillance can provide an indication of not only EGME hematopoietic effects but also an indication of sufficient EGME exposure to affect human reproduction and fetal development.

  5. Molecular dynamics simulations of poly (ethylene oxide) hydration and conformation in solutions

    NASA Astrophysics Data System (ADS)

    Dahal, Udaya; Dormidontova, Elena

    Polyethylene oxide (PEO) is one of the most actively used polymers, especially in biomedical applications due to its high hydrophilicity, biocompatibility and potency to inhibit protein adsorption. PEO solubility and conformation in water depends on its capability to form hydrogen bonds. Using atomistic molecular dynamics simulations we investigated the details of water packing around PEO chain and characterized the type and lifetime of hydrogen bonds in aqueous and mixed solvent solutions. The observed polymer chain conformation varies from an extended coil in pure water to collapsed globule in hexane and a helical-like conformation in pure isobutyric acid or isobutyric acid -water mixture in agreement with experimental observations. We'll discuss the implications of protic solvent arrangement and stability of hydrogen bonds on PEO chain conformation and mobility. This research is supported by NSF (DMR-1410928).

  6. Effect of microgravity on stress ethylene and carbon dioxide production in sweet clover (Melilotus alba L.)

    NASA Technical Reports Server (NTRS)

    Gallegos, Gregory L.; Odom, William R.; Guikema, James A.

    1995-01-01

    The study of higher plant growth and development in the microgravity (micro-g) environment continues to be a challenge. This is in part a result of the available flight qualified hardware with restrictive closed gas environments. This point is underscored by considering that gas exchange of seedlings grown in microgravity may be further limited owing to a thicker layer of water wicked onto the roots and to the absence of convective mixing. We hypothesized that seedlings grown under such conditions will experience greater hypoxia in microgravity than at Earth gravity, and thus produce greater stress ethylene. We compared flight and ground samples of sweet clover seedlings grown in the Fluid Processing Apparatus (FPA) during STS-57 and found them to contain extremely high levels of carbon dioxide (CO2) and stress ethylene. There were time dependent increases for both gases, and seedling growth was greatly inhibited. We repeated these experiments aboard STS-60 using modified chambers which increased, by fifty fold, the air available to the developing seedlings. Sweet clover seed germination and subsequent seedling growth to eight days within the FPA modified with a gas permeable membrane is not compromised by the microgravity environment.

  7. Gamma-ray irradiation, autoclave and ethylene oxide sterilization to thermosetting polyurethane: Sterilization to polyurethane

    NASA Astrophysics Data System (ADS)

    Hirata, Noriko; Matsumoto, Ken-Ichi; Inishita, Takashi; Takenaka, Yoshinori; Suma, Yasunori; Shintani, Hideharu

    1995-09-01

    Thermosetting polyurethane (PU) is widely used in a large variety of medical devices. 4,4'-methylenedianiline (MDA) was produced from PU by sterilization and it was studied for the relationship between urethane components or polymer characteristics and formation of MDA upon sterilization, using the commercially available dialyzers fabricated with different combination of isocyanate and polyol. We confirmed that the molecular-weight of polyol influenced the production of MDA upon sterilization.

  8. Super Soft All-Ethylene Oxide Polymer Electrolyte for Safe All-Solid Lithium Batteries

    NASA Astrophysics Data System (ADS)

    Porcarelli, Luca; Gerbaldi, Claudio; Bella, Federico; Nair, Jijeesh Ravi

    2016-01-01

    Here we demonstrate that by regulating the mobility of classic -EO- based backbones, an innovative polymer electrolyte system can be architectured. This polymer electrolyte allows the construction of all solid lithium-based polymer cells having outstanding cycling behaviour in terms of rate capability and stability over a wide range of operating temperatures. Polymer electrolytes are obtained by UV-induced (co)polymerization, which promotes an effective interlinking between the polyethylene oxide (PEO) chains plasticized by tetraglyme at various lithium salt concentrations. The polymer networks exhibit sterling mechanical robustness, high flexibility, homogeneous and highly amorphous characteristics. Ambient temperature ionic conductivity values exceeding 0.1 mS cm-1 are obtained, along with a wide electrochemical stability window (>5 V vs. Li/Li+), excellent lithium ion transference number (>0.6) as well as interfacial stability. Moreover, the efficacious resistance to lithium dendrite nucleation and growth postulates the implementation of these polymer electrolytes in next generation of all-solid Li-metal batteries working at ambient conditions.

  9. Titanate nanotubes for reinforcement of a poly(ethylene oxide)/chitosan polymer matrix.

    PubMed

    Porras, R; Bavykin, D V; Zekonyte, J; Walsh, F C; Wood, R J

    2016-05-13

    Soft polyethylene oxide (PEO)/chitosan mixtures, reinforced with hard titanate nanotubes (TiNTs) by co-precipitation from aqueous solution, have been used to produce compact coatings by the 'drop-cast' method, using water soluble PEO polymer and stable, aqueous colloidal solutions of TiNTs. The effects of the nanotube concentration and their length on the hardness and modulus of the prepared composite have been studied using nanoindentation and nanoscratch techniques. The uniformity of TiNT dispersion within the polymer matrix has been studied using transmission electron microscopy (TEM). A remarkable increase in hardness and reduced Young's modulus of the composites, compared to pure polymer blends, has been observed at a TiNT concentration of 25 wt %. The short (up to 30 min) ultrasound treatment of aqueous solutions containing polymers and a colloidal TiNT mixture prior to drop casting has resulted in some improvements in both hardness and reduced Young's modulus of dry composite films, probably due to a better dispersion of ceramic nanotubes within the matrix. However, further (more than 1 h) treatment of the mixture with ultrasound resulted in a deterioration of the mechanical properties of the composite accompanied by a shortening of the nanotubes, as observed by the TEM. PMID:27039947

  10. Titanate nanotubes for reinforcement of a poly(ethylene oxide)/chitosan polymer matrix

    NASA Astrophysics Data System (ADS)

    Porras, R.; Bavykin, D. V.; Zekonyte, J.; Walsh, F. C.; Wood, R. J.

    2016-05-01

    Soft polyethylene oxide (PEO)/chitosan mixtures, reinforced with hard titanate nanotubes (TiNTs) by co-precipitation from aqueous solution, have been used to produce compact coatings by the ‘drop-cast’ method, using water soluble PEO polymer and stable, aqueous colloidal solutions of TiNTs. The effects of the nanotube concentration and their length on the hardness and modulus of the prepared composite have been studied using nanoindentation and nanoscratch techniques. The uniformity of TiNT dispersion within the polymer matrix has been studied using transmission electron microscopy (TEM). A remarkable increase in hardness and reduced Young’s modulus of the composites, compared to pure polymer blends, has been observed at a TiNT concentration of 25 wt %. The short (up to 30 min) ultrasound treatment of aqueous solutions containing polymers and a colloidal TiNT mixture prior to drop casting has resulted in some improvements in both hardness and reduced Young’s modulus of dry composite films, probably due to a better dispersion of ceramic nanotubes within the matrix. However, further (more than 1 h) treatment of the mixture with ultrasound resulted in a deterioration of the mechanical properties of the composite accompanied by a shortening of the nanotubes, as observed by the TEM.

  11. Super Soft All-Ethylene Oxide Polymer Electrolyte for Safe All-Solid Lithium Batteries

    PubMed Central

    Porcarelli, Luca; Gerbaldi, Claudio; Bella, Federico; Nair, Jijeesh Ravi

    2016-01-01

    Here we demonstrate that by regulating the mobility of classic −EO− based backbones, an innovative polymer electrolyte system can be architectured. This polymer electrolyte allows the construction of all solid lithium-based polymer cells having outstanding cycling behaviour in terms of rate capability and stability over a wide range of operating temperatures. Polymer electrolytes are obtained by UV-induced (co)polymerization, which promotes an effective interlinking between the polyethylene oxide (PEO) chains plasticized by tetraglyme at various lithium salt concentrations. The polymer networks exhibit sterling mechanical robustness, high flexibility, homogeneous and highly amorphous characteristics. Ambient temperature ionic conductivity values exceeding 0.1 mS cm−1 are obtained, along with a wide electrochemical stability window (>5 V vs. Li/Li+), excellent lithium ion transference number (>0.6) as well as interfacial stability. Moreover, the efficacious resistance to lithium dendrite nucleation and growth postulates the implementation of these polymer electrolytes in next generation of all-solid Li-metal batteries working at ambient conditions. PMID:26791572

  12. Oxidative stability of fermented meat products.

    PubMed

    Wójciak, Karolina M; Dolatowski, Zbigniew J

    2012-04-01

    Meat and meat products, which form a major part of our diet, are very susceptible to quality changes resulting from oxidative processes. Quality of fermented food products depends on the course of various physicochemical and biochemical processes. Oxidation of meat components in raw ripening products may be the result of enzymatic changes occurring as a result of activity of enzymes originating in tissues and microorganisms, as well as lipid peroxidation by free radicals. Primary and secondary products of lipid oxidation are extremely reactive and react with other components of meat, changing their physical and chemical properties. Oxidised proteins take on a yellowish, red through brown hue. Products of lipid and protein degradation create a specific flavour and aroma ; furthermore, toxic substances (such as biogenic amines or new substances) are formed as a result of interactions between meat components, e.g. protein-lipid or protein-protein combinations, as well as transverse bonds in protein structures. Oxidation of meat components in raw ripening products is a particularly difficult process. On the one hand it is essential, since the enzymatic and non-enzymatic lipid oxidation creates flavour and aroma compounds characteristic for ripening products; on the other hand excessive amounts or transformations of those compounds may cause the fermented meat product to become a risk to health. PMID:22493153

  13. Crystallization of poly(ethylene oxide) with acetaminophen--a study on solubility, spherulitic growth, and morphology.

    PubMed

    Yang, Min; Gogos, Costas

    2013-11-01

    A simple, sensitive, efficient, and novel method analyzing the number of spherulitic nuclei was proposed to estimate the solubility of a model drug acetaminophen (APAP) in poly(ethylene oxide) (PEO). At high crystallization temperature (323 K), 10% APAP-PEO had the same low number of spherulitic nuclei as pure PEO, indicating that APAP and PEO were fully miscible. At low crystallization temperature (303 K), the number of nuclei for 10% APAP-PEO was significantly higher, suggesting that APAP was oversaturated and therefore recrystallized and acted as a nucleating agent. Based on the results obtained, the solubility of APAP in PEO is possibly between the concentration of 0.1% and 1% at 303 K. The spherulitic growth rate G of PEO was found to decrease with increasing APAP concentration, suggesting that APAP is most likely functioning as a chemical defect and is either rejected from or included in the PEO crystals during chain folding. APAP could possibly locate in the inter-spherulitic, inter-fibrillar, inter-lamellar, or intra-lamellar regions of PEO. At 323 K, the morphology of 10% APAP-PEO is more dendritic than spherulitic with large unfilled space in between dendrites and spherulites, which is a sign of one or the combination of the four modes of segregation. An extensive spherulitic nucleation and growth kinetics study using the classical theoretical relationships, for example, the Hoffman-Lauritzen (HL) and Avrami theories, was conducted. Both microscopic and differential scanning calorimetric (DSC) analysis yielded similar values for the nucleation constant Kg as well as the fold surface free energy σe and work of chain folding q. The values of σe and q increased with APAP concentration, indicating that the chain folding of PEO was hindered by APAP. PMID:23562611

  14. A scanning electron microscopic study of in vitro toxicity of ethylene-oxide-sterilized bone repair materials.

    PubMed

    Zislis, T; Martin, S A; Cerbas, E; Heath, J R; Mansfield, J L; Hollinger, J O

    1989-01-01

    Polylactic acid (PLA) and polyglycolic acid (PGA) have been under investigation for use in the management of hard- and soft-tissue wounds. Current research has included the incorporation of osteo-inductive substances into a PLA-PGA copolymer alloplastic implant material for enhancement of the healing of osseous defects. Conventional methods of sterilization--such as dry heat, steam heat, or 60Co--tend either to destroy or attenuate osteo-inductive activity and alter polymer biodegradation. Ethylene oxide (EO) gas sterilization is currently being tested as an alternate method. This study examined the relationship of EO-induced cytotoxicity to the length of time of polymer aeration following EO sterilization. Three groups of copolymer implant discs were studied: (1) 50:50 PLA-PGA copolymer, (2) PLA-PGA polymer with hydroxyapatite (HA), and (3) PLA-PGA with autolyzed, antigen-extracted (AA) bone particles. Polymer discs, as well as particulate HA and AA bone controls, were sterilized with EO for 12 hours. Following periods of two weeks, one week, one day, or no subsequent vacuum aeration, samples were placed into 24-well culture plates. A suspension of human fibroblasts was added to each well. Cell growth and attachment were permitted for 24 hours. Medium was then removed, and solutions for cell fixation, buffer washing, and dehydration were added to each well. SEM examination revealed changes in cell growth with increasing periods of aeration suggestive of increasing cell vitality. Cells growing on discs having no aeration were small, round, and lobulated, whereas those of seven to 14 days' aeration were more numerous, and flattened with many microvilli, pseudopodia, and dendritic processes, features consistent with normal cell morphology. These results suggest that EO-sterilized polymer implants should be aerated for least seven to 14 days prior to surgical use. PMID:2561372

  15. Prediction of acetaminophen's solubility in poly(ethylene oxide) at room temperature using the Flory-Huggins theory.

    PubMed

    Yang, Min; Wang, Peng; Gogos, Costas

    2013-01-01

    Solid dispersion technologies such as hot-melt extrusion and spray drying are often used to enhance the solubility of poorly soluble drugs. The biggest challenge associated with solid dispersion systems is that amorphous drugs may phase-separate from the polymeric matrix and recrystallize during storage. A more fundamental understanding of drug-polymer mixtures is needed for the industry to embrace the solid dispersion technologies. In this study, a theoretical model based on Flory-Huggins lattice theory was utilized to predict the solubility of a model drug acetaminophen (APAP) in a semi-crystalline polymer poly(ethylene oxide) (PEO) at 300 K. The interaction parameter χ was calculated to be -1.65 from the depression of drug's melting temperature determined from rheological and differential scanning calorimetry analysis. The equilibrium solubility in amorphous PEO was estimated to be 11.7% at 300 K. Assuming no APAP molecules dissolve in the crystalline part of PEO, the adjusted theoretical solubility is around 2.3% considering PEO being 80% crystalline. The solubility of APAP in PEG 400 was calculated to be 14.6% by using the same χ value, close to the experimental measurement 17.1%. The drug's solubility could be altered noticeably by the change of both χ and polymer molecular weight. The study also suggests that the depression of drug's melting point is a good indicator for preliminary polymer screening. The polymer that reduces the melting point the most is likely to be most miscible with the drug. PMID:22356356

  16. Bioengineering Functional Copolymers. IX. Poly[(maleic anhydride-co-hexene-1)-g-poly(ethylene oxide)].

    PubMed

    Mazi, Hidayet; Kibarer, Günay; Emregül, Emel; Rzaev, Zakir M O

    2006-04-12

    Amphiphilic bioengineering copolymers having a combination of hydrophilic/hydrophobic linkages and polyelectrolyte behavior, along with an ability to interact with biomacromolecules, in particular with the invertase enzyme, have been synthesized by (a) complex-radical copolymerization of maleic anhydride (MA, the acceptor) and hexene-1 (H-1, the donor) monomers with benzoyl peroxide as the initiator in 1,4-dioxane at 65 degrees C under high-conversion conditions and (b) subsequent grafting (polyesterification) of synthesized poly(MA-alt-H-1) with alpha-methoxy-omega-hydroxy-poly(ethylene oxide) (PEO). Copolymerizations were also carried out in the steady state, in order to essentially reduce the effect of copolymer composition drift. The values of the monomer reactivity ratios (r(1) and r(2)) determined by using the known terminal models of Fineman-Ross (FR) and Kelen-Tüdös (KT), as well as by nonlinear regression (NLR) analysis, are: r(1) = 0.16 and r(2) = 0.30 (FR), r(1) = 0.14 and r(2) = 0.27 (KT), and r(1) = 0.15 and r(2) = 0.29 (NLR), respectively. All the copolymers and graft copolymers were characterized by FTIR spectroscopy, (1)H{(13)C} NMR spectroscopy, viscometric measurements, and chemical (acid number), thermal (DSC and TGA), and X-ray diffraction analyses. Unlike poly(MA-alt-H-1)s, PEO macrobranched graft copolymers exhibit expressed polyelectrolyte and swelling behavior in diluted and concentrated dioxane solutions, respectively. The copolymer and its PEO hyperbranched derivatives can be used as carriers for enzyme immobilization. PMID:16572476

  17. A study of release mechanisms of different ophthalmic drugs from erodible ocular inserts based on poly(ethylene oxide).

    PubMed

    Di Colo, G; Zambito, Y

    2002-09-01

    When topical controlled delivery of ophthalmic drugs is realised via erodible inserts, drug bioavailability is maximised, if release is controlled exclusively by insert erosion, since parallel mechanisms which increase the release rate, also increases the dose fraction cleared from the precorneal area by tear fluid draining. The respective contributions of diffusion and erosion to the release mechanism of different drugs, namely, prednisolone (PDS), oxytetracycline hydrochloride (OTH) and gentamicin sulfate (GTS), from erodible ocular inserts based on poly(ethylene oxide) (PEO) of molecular weight 400 or 900kDa was determined by an in vitro technique adequate to predict the release mechanism in vivo. PDS and OTH were released with erosion-controlled kinetics. With therapeutic doses of these drugs in the inserts (0.3mg, 1.5%), the possibility of a purely erosive mechanism was shown to rely upon drug-PEO molecular interactions, which limit drug diffusion in the swollen matrix. This was the case with OTH, for which strong interactions with PEO were measured, whereas some contribution from the parallel diffusive mechanism was evidenced for PDS, which showed weaker interactions with polymer. Such a contribution disappeared when the PDS concentration in the insert was increased to 6%, which suggested that the erosive mechanism is favoured by a drug concentration in the hydrated insert substantially higher than solubility. On the other hand, the release of about 50% GTS dose was controlled by diffusion, due to the high water solubility of this drug, accompanied by weak drug-PEO interactions. In this case the residence time of drug in the precorneal area is expected to be significantly shorter than that of the PEO carrier. PMID:12191691

  18. Nitric oxide mediates strigolactone signaling in auxin and ethylene-sensitive lateral root formation in sunflower seedlings

    PubMed Central

    Bharti, Niharika; Bhatla, Satish C

    2015-01-01

    Strigolactones (SLs) play significant role in shaping root architecture whereby auxin-SL crosstalk has been observed in SL-mediated responses of primary root elongation, lateral root formation and adventitious root (AR) initiation. Whereas GR24 (a synthetic strigolactone) inhibits LR and AR formation, the effect of SL biosynthesis inhibitor (fluridone) is just the opposite (root proliferation). Naphthylphthalamic acid (NPA) leads to LR proliferation but completely inhibits AR development. The diffusive distribution of PIN1 in the provascular cells in the differentiating zone of the roots in response to GR24, fluridone or NPA treatments further indicates the involvement of localized auxin accumulation in LR development responses. Inhibition of LR formation by GR24 treatment coincides with inhibition of ACC synthase activity. Profuse LR development by fluridone and NPA treatments correlates with enhanced [Ca2+]cyt in the apical region and differentiating zones of LR, indicating a critical role of [Ca2+] in LR development in response to the coordinated action of auxins, ethylene and SLs. Significant enhancement of carotenoid cleavage dioxygenase (CCD) activity (enzyme responsible for SL biosynthesis) in tissue homogenates in presence of cPTIO (NO scavenger) indicates the role of endogenous NO as a negative modulator of CCD activity. Differences in the spatial distribution of NO in the primary and lateral roots further highlight the involvement of NO in SL-modulated root morphogenesis in sunflower seedlings. Present work provides new report on the negative modulation of SL biosynthesis through modulation of CCD activity by endogenous nitric oxide during SL-modulated LR development. PMID:26076049

  19. Performance of polymer electrolyte based on chitosan blended with poly(ethylene oxide) for plasmonic dye-sensitized solar cell

    NASA Astrophysics Data System (ADS)

    Buraidah, M. H.; Teo, L. P.; Au Yong, C. M.; Shah, Shahan; Arof, A. K.

    2016-07-01

    Chitosan and poly(ethylene oxide) powders have been mixed in different weight ratios. To each mixture, a fixed amount of ammonium iodide has been added. All mixtures have been dissolved in 1% acetic acid solution to form polymer blend electrolyte films by the solution cast technique. X-ray diffraction indicates that the polymer blend electrolytes are amorphous. Fourier transform infrared spectroscopy shows shifting of the amine, carboxamide and Csbnd Osbnd C bands to lower wavenumbers indicating the occurrence of complexation. Electrochemical impedance spectroscopy has been used to study the electrical properties of the samples. The ionic conductivity for 55 wt.% chitosan-45 wt.% NH4I electrolyte system is 3.73 × 10-7 S cm-1 at room temperature and is increased to 3.66 × 10-6 S cm-1 for the blended film (16.5 wt.% chitosan-38.5 wt.% PEO)-45 wt.% NH4I film. Dye-sensitized solar cells (DSSCs) have been fabricated by sandwiching the polymer electrolyte between the TiO2/dye photoelectrode and Pt counter electrode. DSSCs fabricated exhibits short-circuit current density (Jsc) of 2.71 mA cm-2, open circuit voltage (Voc) of 0.58 V and efficiency of 0.78% with configuration ITO/TiO2/N3 dye/(16.5 wt.% chitosan-38.5 wt.% PEO)-45 wt.% NH4I(+I2)/Pt/ITO and Jsc of 2.84 mA cm-2, Voc of 0.58 V and efficiency of 1.13% with configuration ITO/TiO2 + Ag nanoparticles/N3 dye/(16.5 wt.% chitosan-38.5 wt.% PEO)-45 wt.% NH4I(+I2)/Pt/ITO.

  20. Carnosine facilitates nitric oxide production in endothelial f-2 cells.

    PubMed

    Takahashi, Satoru; Nakashima, Yukiko; Toda, Ken-Ichi

    2009-11-01

    We examined the effect of carnosine (beta-alanyl-histidine) on nitric oxide (NO) production and endothelial NO synthase (eNOS) activation in endothelial F-2 cells. Carnosine enhanced NO production in a dose-dependent manner, and the stimulatory effect of carnosine was observed at concentrations exceeding 5 mM. The carnosine-stimulated NO production was inhibited by N(G)-nitro-L-arginine methyl ester, but not by N(G)-nitro-D-arginine methyl ester. In contrast, beta-alanine, histidine (carnosine components) and anserine (N-methyl carnosine) failed to increase NO production. Carnosine had no effect on NO production for the initial 5 min, but thereafter resulted in a gradual increase in NO production up to 15 min. Carnosine did not induce phosphorylation of eNOS at Ser1177. The carnosine-induced increase in NO production was observed even when extracellular Ca2+ was depleted by ethylene glycol bis(2-aminoethyl ether)-N,N,N'-N'-tetraacetic acid however, the effect was abolished upon depletion of intracellular Ca2+ by BAPTA. After F-2 cells were incubated with carnosine for 4 min, intracellular Ca2+ concentration gradually increased. The carnosine-induced increase in intracellular Ca2+ concentration occurred even in the absence of extracellular Ca2+. These results indicate that carnosine facilitates NO production in endothelial F-2 cells. It is also suggested that eNOS is activated by Ca2+, which might be released from intracellular Ca2+ stores in response to carnosine. PMID:19881293

  1. Effect of poly(ethylene oxide)-silane graft molecular weight on the colloidal properties of iron oxide nanoparticles for biomedical applications.

    PubMed

    Barrera, Carola; Herrera, Adriana P; Bezares, Nayla; Fachini, Estevão; Olayo-Valles, Roberto; Hinestroza, Juan P; Rinaldi, Carlos

    2012-07-01

    The size, charge, and stability of colloidal suspensions of magnetic nanoparticles with narrow size distribution and grafted with poly(ethylene glycol)-silane of different molecular weights were studied in water, biological buffers, and cell culture media. X-ray photoelectron spectroscopy provided information on the chemical nature of the nanoparticle surface, indicating the particle surfaces consisted of a mixture of amine groups and grafted polymer. The results indicate that the exposure of the amine groups on the surface decreased as the molecular weight of the polymer increased. The hydrodynamic diameters correlated with PEG graft molecular weight and were in agreement with a distributed density model for the thickness of a polymer shell end-grafted to a particle core. This indicates that the particles obtained consist of single iron oxide cores coated with a polymer brush. Particle surface charge and hydrodynamic diameter were measured as a function of pH, ionic strength, and in biological buffers and cell culture media. DLVO theory was used to analyze the particle stability considering electrostatic, magnetic, steric, and van der Waals interactions. Experimental results and colloidal stability theory indicated that stability changes from electrostatically mediated for a graft molecular weight of 750 g/mol to sterically mediated at molecular weights of 1000 g/mol and above. These results indicate that a graft molecular weight above 1000 g/mol is needed to produce particles that are stable in a wide range of pH and ionic strength, and in cell culture media. PMID:22513169

  2. The role of gravity in apical dominance: effects of clinostating on shoot inversion-induced ethylene production, shoot elongation and lateral bud growth

    NASA Technical Reports Server (NTRS)

    Prasad, T. K.; Cline, M. G.

    1987-01-01

    Shoot inversion-induced release of apical dominance in Pharbitis nil is inhibited by rotating the plant at 0.42 revolutions per minute in a vertical plane perpendicular to the axis of rotation of a horizontal clinostat. Clinostating prevented lateral bud outgrowth, apparently by negating the restriction of the shoot elongation via reduction of ethylene production in the inverted shoot. Radial stem expansion was also decreased. Data from experiments with intact tissue and isolated segments indicated that shoot-inversion stimulates ethylene production by increasing the activity of 1-aminocyclopropane-1-carboxylic acid synthase. The results support the hypothesis that shoot inversion-induced release of apical dominance in Pharbitis nil is due to gravity stress and is mediated by ethylene-induced retardation of the elongation of the inverted shoot.

  3. FT-IR and {sup 1}H NMR characterization of the products of an ethylene inverse diffusion flame

    SciTech Connect

    Santamaria, Alexander; Mondragon, Fanor; Molina, Alejandro; Marsh, Nathan D.; Eddings, Eric G.; Sarofim, Adel F.

    2006-07-15

    Knowledge of the chemical structure of young soot and its precursors is very useful in the understanding of the paths leading to soot particle inception. This paper presents analyses of the chemical functional groups, based on FT-IR and {sup 1}H NMR spectroscopy of the products obtained in an ethylene inverse diffusion flame. The trends in the data indicate that the soluble fraction of the soot becomes progressively more aromatic and less aliphatic as the height above the burner increases. Results from {sup 1}H NMR spectra of the chloroform-soluble soot samples taken at different heights above the burner corroborate the infrared results based on proton chemical shifts (Ha, H{alpha}, H{beta}, and H{gamma}). The results indicate that the aliphatic {beta} and {gamma} hydrogens suffered the most drastic reduction, while the aromatic character increased considerably with height, particularly in the first half of the flame. (author)

  4. Jumpstarting commercial-scale CO2 capture and storage with ethylene production and enhanced oil recovery in the US Gulf

    DOE PAGESBeta

    Middleton, Richard S.; Levine, Jonathan S.; Bielicki, Jeffrey M.; Viswanathan, Hari S.; Carey, J. William; Stauffer, Philip H.

    2015-04-27

    CO2 capture, utilization, and storage (CCUS) technology has yet to be widely deployed at a commercial scale despite multiple high-profile demonstration projects. We suggest that developing a large-scale, visible, and financially viable CCUS network could potentially overcome many barriers to deployment and jumpstart commercial-scale CCUS. To date, substantial effort has focused on technology development to reduce the costs of CO2 capture from coal-fired power plants. Here, we propose that near-term investment could focus on implementing CO2 capture on facilities that produce high-value chemicals/products. These facilities can absorb the expected impact of the marginal increase in the cost of production onmore » the price of their product, due to the addition of CO2 capture, more than coal-fired power plants. A financially viable demonstration of a large-scale CCUS network requires offsetting the costs of CO2 capture by using the CO2 as an input to the production of market-viable products. As a result, we demonstrate this alternative development path with the example of an integrated CCUS system where CO2 is captured from ethylene producers and used for enhanced oil recovery in the U.S. Gulf Coast region.« less

  5. Differential responses of certain lichen species to sulfur-containing solutions under acidic conditions as expressed by the production of stress-ethylene

    SciTech Connect

    Garty, J.; Kauppi, M.; Kauppi, A.

    1995-05-01

    To determine whether fluctuations in the concentration of ethylene produced by lichens exposed to sulfur-containing solutions at a low pH correlate with the tolerance/sensitivity of these lichens to air pollution, we measured the amount of ethylene produced by thalli soaked in H{sub 2}SO{sub 4} and NaHSO{sub 3}. The exposure of Hypogymnia physodes, Cladina stellaris, and Bryoria fuscescens to H{sub 2}SO{sub 4} at a pH ranging between 4.0 and 2.0 did not produce changes in the concentration of ethylene in comparison with samples wetted with H{sub 2}O at pH 6.8. The exposure of two pendulous lichens, Usnea hirta and Alectoria sarmentosa, to 1.0 and 5.0 mM H{sub 2}SO{sub 4} at pH 2.7 and 2.0, respectively, stimulated only a slight increase of ethylene production, whereas another pendulous lichen, Bryoria fremontii, exposed to H{sub 2}SO{sub 4} at pH 4.0-2.0 decreased its production of ethylene. The soaking of H. physodes, U. hirta, C. stellaris, and A. sarmentosa thalli in NaHSO{sub 3} at pH 4.0 gradually increased the production of ethylene. The exposure of B. fremontii and B. fuscescens to low NaHSO{sub 3} concentrations depressed the production of ethylene in these lichens. The indifference of H. physodes to H{sub 2}SO{sub 4} under strong acidic conditions correlated with its resistance to SO{sub 21} in the air. In accordance with a model by D.M. Reid (In {open_quotes}Effects of Atmospheric Pollutants on Forests, Wetlands and Agricultural Ecosystems. NATO ASI Series, Springer-Verlag, Berlin and Heidelberg, 1987) referring to higher plants, it is suggested that sulfur-containing solutions under acidic conditions increase the solubility of particles containing heavy metals entrapped among the mycobiont hyphae in lichens. This may lead to an increase of the production of endogenous ethylene in lichens as they are exposed to sulfur-containing chemicals, to acidic rain, or to heavy metal-polluted air. 65 refs., 8 tabs.

  6. Portable Apparatus for Electrochemical Sensing of Ethylene

    NASA Technical Reports Server (NTRS)

    Manoukian, Mourad; Tempelman, Linda A.; Forchione, John; Krebs, W. Michael; Schmitt, Edwin W.

    2007-01-01

    A small, lightweight, portable apparatus based on an electrochemical sensing principle has been developed for monitoring low concentrations of ethylene in air. Ethylene has long been known to be produced by plants and to stimulate the growth and other aspects of the development of plants (including, notably, ripening of fruits and vegetables), even at concentrations as low as tens of parts per billion (ppb). The effects are magnified in plant-growth and -storage chambers wherein ethylene can accumulate. There is increasing recognition in agriculture and related industries that it is desirable to monitor and control ethylene concentrations in order to optimize the growth, storage, and ripening of plant products. Hence, there are numerous potential uses for the present apparatus in conjunction with equipment for controlling ethylene concentrations. The ethylene sensor is of a thick-film type with a design optimized for a low detection limit. The sensor includes a noble metal sensing electrode on a chip and a hydrated solid-electrolyte membrane that is held in contact with the chip. Also located on the sensor chip are a counter electrode and a reference electrode. The sensing electrode is held at a fixed potential versus the reference electrode. Detection takes place at active-triple-point areas where the sensing electrode, electrolyte, and sample gas meet. These areas are formed by cutting openings in the electrolyte membrane. The electrode current generated from electrochemical oxidation of ethylene at the active triple points is proportional to the concentration of ethylene. An additional film of the solid-electrolyte membrane material is deposited on the sensing electrode to increase the effective triple-point areas and thereby enhance the detection signal. The sensor chip is placed in a holder that is part of a polycarbonate housing. When fully assembled, the housing holds the solid-electrolyte membrane in contact with the chip (see figure). The housing includes

  7. Functionalized poly(ethylene glycol)-stabilized water-soluble palladium nanoparticles: property/activity relationship for the aerobic alcohol oxidation in water.

    PubMed

    Feng, Bo; Hou, Zhenshan; Yang, Hanmin; Wang, Xiangrui; Hu, Yu; Li, Huan; Qiao, Yunxiang; Zhao, Xiuge; Huang, Qingfa

    2010-02-16

    The preparation, characterization, and catalytic properties of water-soluble palladium nanoparticles stabilized by the functionalized-poly(ethylene glycol) as a protective ligand were demonstrated for aerobic oxidation of alcohols in aqueous phase. UV/vis spectra and X-ray photoelectron spectroscopy (XPS) proved that there was an electronic interaction between the bidentate nitrogen ligand and palladium atoms. Transmission electron microscopy and XPS analysis showed that the particle size and surface properties of the generated palladium nanoparticles can be controlled by varying the amount of protective ligand and the kinds of reducing agents. It was found that both the size and surface properties of palladium nanoparticles played very important roles in affecting catalytic performance. The stabilized metallic palladium nanoparticles were proven to be the active centers for benzyl alcohol oxidation in the present system, and the water-soluble Pd nanocatalysts can also be extended to the selective oxidation of various alcohols. PMID:20039597

  8. Analysis of sterol oxidation products in foods.

    PubMed

    Guardiola, Francesc; Bou, Ricard; Boatella, Josep; Codony, Rafael

    2004-01-01

    The main aspects related to the analysis of sterol oxidation products (SOP) in foods are comprehensively reviewed. Special emphasis is placed on the critical and controversial points of this analysis because these points affect crucial analytical parameters such as precision, accuracy, selectivity, and sensitivity. The effect of sample preparation and the conditions of quantification by gas chromatography and liquid chromatography on these parameters are also reviewed. The results show that, in order to choose an adequate method to analyze SOP in a certain food, the analyst must consider its SOP concentration and matrix complexity. The term SOP includes both cholesterol oxidation products (COP) and phytosterol oxidation products (POP). The state of the art of COP and POP analysis is quite different; many more studies have dealt with the analysis of COP than of POP. However, most of the results presented here about COP analysis may be extrapolated to POP analysis because both groups of compounds show similar structures and characteristics. PMID:15164841

  9. Custom-made morphologies of ZnO nanostructured films templated by a poly(styrene-block-ethylene oxide) diblock copolymer obtained by a sol-gel technique.

    PubMed

    Sarkar, Kuhu; Rawolle, Monika; Herzig, Eva M; Wang, Weijia; Buffet, Adeline; Roth, Stephan V; Müller-Buschbaum, Peter

    2013-08-01

    Zinc oxide (ZnO) nanostructured films are synthesized on silicon substrates to form different morphologies that consist of foamlike structures, wormlike aggregates, circular vesicles, and spherical granules. The synthesis involves a sol-gel mechanism coupled with an amphiphilic diblock copolymer poly(styrene-block-ethylene oxide), P(S-b-EO), which acts as a structure-directing template. The ZnO precursor zinc acetate dihydrate (ZAD) is incorporated into the poly(ethylene oxide) block. Different morphologies are obtained by adjusting the weight fractions of the solvents and ZAD. The sizes of the structure in solution for different sol-gels are probed by means of dynamic light scattering. Thin-film samples with ZnO nanostructures are prepared by spin coating and solution casting followed by a calcination step. On the basis of various selected combinations of weight fractions of the ingredients used, a ternary phase diagram is constructed to show the compositional boundaries of the investigated morphologies. The evolution and formation mechanisms of the morphologies are addressed in brief. The surface morphologies of the ZnO nanostructures are studied with SEM. The inner structures of the samples are probed by means of grazing incidence small-angle X-ray scattering to complement the SEM investigations. XRD measurements confirm the crystallization of the ZnO in the wurtzite phase upon calcination of the nanocomposite film in air. The optical properties of ZnO are analyzed by FTIR and UV/Vis spectroscopy. PMID:23881752

  10. Production of pesticide metabolites by oxidative reactions.

    PubMed

    Hodgson, E

    1982-08-01

    The cytochrome P-450-dependent monooxygenase system catalyzes a wide variety of oxidations of pesticide chemicals and related compounds. These reactions include epoxidation and aromatic hydroxylation, aliphatic hydroxylation, O-, N- and S-dealkylation, N-oxidation, oxidative deamination, S-oxidation, P-oxidation, desulfuration and ester cleavage and may result in either detoxication or activation of the pesticide. The current status of such reactions, relative to the production, in vivo, of biologically active intermediates in pesticide metabolism is summarized. More recently we have shown that the FAD-containing monooxygenase of mammalian liver (E.C.1.14.13.8), a xenobiotic metabolizing enzyme of broad specificity formerly known as an amine oxidase, is involved in a variety of pesticide oxidations. These include sulfoxidation of organophosphorus insecticides such as phorate and disulfoton, oxidative desulfuration of phosphonate insecticides such as fonofos and oxidation at the phosphorus atom in such compounds as the cotton defoliant, folex. The relative importance of the FAD-containing monooxygenase vis-a-vis the cytochrome P-450-dependent monooxygenase system is discussed, based on in vitro studies on purified enzymes. PMID:7161848

  11. Effects of temperature and dissolved lithium perchlorate on the viscoelastic and dynamic properties of poly(ethylene oxide), (PEO) melts

    NASA Astrophysics Data System (ADS)

    Bogoslovov, Radoslav B.

    Poly(ethylene oxide)/lithium perchlorate (PEO/LiClO4) complexes are widely studied as a prototype solid polymer electrolyte in rechargeable lithium-polymer batteries. Characterizing the structure and dynamics of the system in its molten state is important for understanding the role of the polymer environment in lithium ion transport and conductivity. A fiber-optic coupled Fabry-Perot interferometer is employed in the investigation of the electrolyte viscoelastic and dynamic properties, which are both related to the intrachain local mobility and therefore to ion diffusion. The properties of the system are studied as a function of composition, temperature, and frequency. Structural relaxation processes are observed both in the neat polymer melt and in the salt containing electrolytes. For the neat PEO-1K melt the relaxation is identified as Maxwell-Debye single-exponential relaxation (beta = 1). The relaxation time follows Arrhenius temperature dependence with activation energy of the order of 10-11 kJ/mol. Upon addition of salt, the character of the relaxation persists with beta = 1, while the characteristic relaxation time slows down and the activation energy increases slightly. The slowdown of the dynamics is more pronounced at lower temperatures. In addition, with increasing salt concentration the elastic modulus increases significantly making the system stiffer at all temperatures, while the maximum of the storage modulus is shifted to higher temperatures. These effects result in a decrease in polymer segmental mobility and consequently in reduction of lithium ion diffusivity, with increased salt concentration. A unique q-dependent measurement is performed, allowing the investigation of the Brillouin frequency and linewidth as a function of frequency. It revealed a double-step relaxation in the electrolyte. The two relaxations are identified as secondary relaxations with Maxwell-Debye character (beta=1). The lower-frequency relaxation is stronger and has

  12. Release of Bacteriocins from Nanofibers Prepared with Combinations of Poly(d,l-lactide) (PDLLA) and Poly(Ethylene Oxide) (PEO)

    PubMed Central

    Heunis, Tiaan; Bshena, Osama; Klumperman, Bert; Dicks, Leon

    2011-01-01

    Plantaricin 423, produced by Lactobacillus plantarum, and bacteriocin ST4SA produced by Enterococcus mundtii, were electrospun into nanofibers prepared from different combinations of poly(d,l-lactide) (PDLLA) and poly(ethylene oxide) (PEO) dissolved in N,N-dimethylformamide (DMF). Both peptides were released from the nanofibers with a high initial burst and retained 88% of their original antimicrobial activity at 37 °C. Nanofibers have the potential to serve as carrier matrix for bacteriocins and open a new field in developing controlled antimicrobial delivery systems for various applications. PMID:21731433

  13. Biohydrogen production in a three-phase fluidized bed bioreactor using sewage sludge immobilized by ethylene-vinyl acetate copolymer.

    PubMed

    Lin, Chi-Neng; Wu, Shu-Yii; Chang, Jian-Sheng; Chang, Jo-Shu

    2009-07-01

    Ethylene-vinyl acetate (EVA) copolymer was used to immobilize H(2)-producing sewage sludge for H(2) production in a three-phase fluidized bed reactor (FBR). The FBR with an immobilized cell packing ratio of 10% (v/v) and a liquid recycle rate of 5l/min (23% bed expansion) was optimal for dark H(2) fermentation. The performance of the FBR reactor fed with sucrose-based synthetic medium was examined under various sucrose concentration (C(so)) and hydraulic retention time (HRT). The best volumetric H(2) production rate of 1.80+/-0.02 H(2) l/h/l occurred at C(so)=40 g COD/l and 2h HRT, while the optimal H(2) yield (4.26+/-0.04 mol H(2)/mol sucrose) was obtained at C(so)=20 g COD/l and 6h HRT. The H(2) content in the biogas was stably maintained at 40% or above. The primary soluble metabolites were butyric acid and acetic acid, as both products together accounted for 74-83% of total soluble microbial products formed during dark H(2) fermentation. PMID:19318247

  14. The monooxidation of ethylene with hydrogen peroxide on the per-FTPhPFe3+OH/Al2O3 biomimetic

    NASA Astrophysics Data System (ADS)

    Nasirova, U. V.; Gasanova, L. M.; Nagiev, T. M.

    2010-06-01

    The gas-phase monooxidation of ethylene by hydrogen peroxide on a biomimetic heterogeneous catalyst (per-FTPhPFe3+OH/Al2O3) was studied under comparatively mild conditions. The biomimetic oxidation of ethylene with hydrogen peroxide was shown to be coherently synchronized with the decomposition of H2O2. Depending on reaction medium conditions, one of two desired products was formed, either ethanol or acetaldehyde. The kinetics and probable mechanism of ethylene transformation were studied.

  15. Ethylene-producing bacteria that ripen fruit.

    PubMed

    Digiacomo, Fabio; Girelli, Gabriele; Aor, Bruno; Marchioretti, Caterina; Pedrotti, Michele; Perli, Thomas; Tonon, Emil; Valentini, Viola; Avi, Damiano; Ferrentino, Giovanna; Dorigato, Andrea; Torre, Paola; Jousson, Olivier; Mansy, Sheref S; Del Bianco, Cristina

    2014-12-19

    Ethylene is a plant hormone widely used to ripen fruit. However, the synthesis, handling, and storage of ethylene are environmentally harmful and dangerous. We engineered E. coli to produce ethylene through the activity of the ethylene-forming enzyme (EFE) from Pseudomonas syringae. EFE converts a citric acid cycle intermediate, 2-oxoglutarate, to ethylene in a single step. The production of ethylene was placed under the control of arabinose and blue light responsive regulatory systems. The resulting bacteria were capable of accelerating the ripening of tomatoes, kiwifruit, and apples. PMID:25393892

  16. Nuclear magnetic resonance investigation of dynamics in poly(ethylene oxide) based polyether-ester-sulfonate ionomers

    NASA Astrophysics Data System (ADS)

    Roach, David J.

    Nuclear magnetic resonance (NMR) spectroscopy has been utilized to investigate the dynamics of poly(ethylene oxide)-based lithium sulfonate ionomer samples that have low glass transition temperatures. 1H and 7Li spin-lattice relaxation times (T1) of the bulk polymer and lithium ions, respectively, were measured and analyzed in samples with a range of ion contents. The temperature dependence of T1 values along with the presence of minima in T1 as a function of temperature enabled correlation times and activation energies to be obtained for both the segmental motion of the polymer backbone and the hopping motion of lithium cations. Similar activation energies for motion of both the polymer and lithium ions in the samples with lower ion content indicate that the polymer segmental motion and lithium ion hopping motion are correlated in these samples, even though lithium hopping is about ten times slower than the segmental motion. A divergent trend is observed for correlation times and activation energies of the highest ion content sample with 100% lithium sulfonation due to the presence of ionic aggregation. Details of the polymer and cation dynamics on the nanosecond timescale are discussed and complement the findings of X-ray scattering and Quasi Elastic Neutron Scattering experiments. Polymer backbone dynamics of single ion conducting poly(ethylene oxide) (PEO)-based ionomer samples with low glass transition temperatures (T g) have been investigated using solid-state nuclear magnetic resonance (NMR). Experiments detecting 13C with 1H decoupling under magic angle spinning (MAS) conditions identified the different components and relative mobilities of the polymer backbone of a suite of. lithium- and sodium-containing ionomer samples with varying cation contents. Variable temperature (203-373 K) 1H-13C cross-polarization MAS (CP-MAS) experiments also provided qualitative assessment of the differences in the motions of the polymer backbone components as a function of

  17. Ethylene production by ODHE in catalytically modified Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ) membrane reactors.

    PubMed

    Lobera, M Pilar; Escolástico, Sonia; Garcia-Fayos, Julio; Serra, José M

    2012-08-01

    Process intensification by the integration of membranes and high-temperature reactors offers several advantages with regard to conventional process schemes, that is, energy saving, safe operation, reduced plant/unit size, and higher process performance, for example, higher productivity, catalytic activity, selectivity, or stability. We present the study of oxidative dehydrogenation of ethane at 850 °C on a catalytic membrane reactor based on a mixed ionic-electronic conducting membrane. The surface of the membrane made of Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ) has been activated by using different porous catalytic layers based on perovskites. The layer was deposited by screen printing, and the porosity and thickness was studied for the catalyst composition. The different catalyst formulations are based on partial substitution of A- and B-site atoms of doped strontium ferrite/cobaltites (A(0.6)Sr(0.4)Co(0.5)Fe(0.5)O(3-δ) and Ba(0.6)Sr(0.4)BO(3-δ)) and were synthesized by an ethylenediaminetetraacetic acid-citrate complexation route. The use of a disk-shaped membrane in the reactor enabled the direct contact of gaseous oxygen and hydrocarbons to be avoided, and thus, the ethylene content increased. High ethylene yields (up to ≈81 %) were obtained by using a catalytic coating based on Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ), which included macropores produced by the addition of graphite platelets into the screen-printing ink. The promising catalytic results obtained with this catalytically modified membrane reactor are attributed to the combination of 1) the high activity, as a result of the high temperature and oxygen species diffusing through the membrane; 2) the control of oxygen dosing and the low concentration of molecules in the gas phase; and 3) suitable fluid dynamics, which enables appropriate feed contact with the membrane and the rapid removal of products. PMID:22791570

  18. Novel mechanism for the radiation-induced bystander effect: nitric oxide and ethylene determine the response in sponge cells.

    PubMed

    Müller, Werner E G; Ushijima, Hiroshi; Batel, Renato; Krasko, Anatoli; Borejko, Alexandra; Müller, Isabel M; Schröder, Heinz-C

    2006-05-11

    Until now the bystander effect had only been described in vertebrates. In the present study the existence of this effect has been demonstrated for the phylogenetically oldest metazoan phylum, the Porifera. We used the demosponge Suberites domuncula for the experiments in the two-chamber-system. The lower dish contained irradiated "donor" cells (single cells) and the upper dish the primmorphs ("recipient" primmorphs). The "donor" cells were treated with UV-B light (40 mJ/cm2) and 100 microM hydrogen peroxide (H2O2), factors that exist also in the natural marine aquatic environment of sponges; these factors caused a high level of DNA strand breaks followed by a reduced viability of the cells. If these cells were added to the "recipient" primmorphs these 3D-cell cultures started to undergo apoptosis. This effect could be abolished by the NO-specific scavenger PTIO and ethylene. The conclusion that NO is synthesized by the UV-B/H2O2-treated cells was supported analytically. The cDNA encoding the enzyme dimethylarginine dimethylaminohydrolase (DDAH) was isolated from the "donor" cells. High levels of DDAH transcripts were measured in UV-B/H2O2-treated "donor" cells while after ethylene treatment the steady-state level of expression drops drastically. We conclude that in the absence of ethylene the concentration of the physiological inhibitor for the NO synthase ADMA is low, due to the high level of DDAH. In consequence, high amounts of NO are released from "donor" cells which cause apoptosis in "recipient" primmorphs. In contrast, ethylene reduces the DDAH expression with the consequence of higher levels of ADMA which prevent the formation of larger amounts of NO. This study describes the radiation-induced bystander effect also for the most basal metazoans and demonstrates that this effect is controlled by the two gases NO and ethylene. PMID:16427660

  19. Ethylene effects in pea stem tissue

    SciTech Connect

    Steen, D.A.; Chadwick, A.V.

    1981-01-01

    The marked effects of ethylene on pea stem growth have been investigated. Low temperatures and colchicine, both known microtubule depolymerization agents, reverse the effects of ethylene in straight growth tests. Low temperature (6 C) also profoundly reduces the effects of gas in terms of swelling, hook curvature, and horizontal mutation. Deuterium oxide, an agent capable of rigidifying microtubular structure, mimics the effects of ethylene. Electron microscopy shows that microtubule orientation is strikingly altered by ethylene. These findings indicate that some of the ethylene responses may be due to a stabilizing effect on microtubules in plant cells.

  20. Ethylene and a-farnesene metabolism in green and red skin of three apple cultivars in response to 1-methylcyclopropene (1-MCP)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Relationships among alpha-farnesene synthesis and oxidation, ethylene production and perception, antioxidative enzyme activities, and superficial scald development in fruit of three commercial apple cultivars were investigated at the biochemical and gene transcriptional levels. Scald-susceptible Cor...

  1. Poly(ethylene oxide)-silica hybrids entrapping sensitive dyes for biomedical optical pH sensors: Molecular dynamics and optical response

    NASA Astrophysics Data System (ADS)

    Fabbri, Paola; Pilati, Francesco; Rovati, Luigi; McKenzie, Ruel; Mijovic, Jovan

    2011-06-01

    Polymer-silica hybrid nanocomposites prepared by sol-gel process based on triethoxisilane-terminated poly(ethylene oxide) chains and tetraethoxysilane as silica precursor, doped with organic pH sensitive dyes, have been prepared and their suitability for use as sensors coupled with plastic optic fibers has been evaluated. Sensors were prepared by immobilizing a drop of the hybrid materials onto the tip of a multi-mode poly(methyl methacrylate) optical fiber. The performance of the optical sensor in terms of sensitivity and response time was tested in different experimental conditions, and was found to be markedly higher than analogous sensors present on the market. The very fast kinetic of the hybrid's optical response was supported by studies performed at the molecular level by broadband dielectric relaxation spectroscopy (DRS), investigated over a wide range of frequency and temperature, showing that poly(ethylene oxide) chains maintain their dynamics even when covalently bonded to silica domains, which decrease the self-association interactions and promote motions of polymer chain segments. Due to the fast response kinetic observed, these pH optical sensors result suitable for the fast-detection of biomedical parameters, i.e. fast esophageous pH-metry.

  2. Recyclable magnetic nanocluster crosslinked with poly(ethylene oxide)-block-poly(2-vinyl-4,4-dimethylazlactone) copolymer for adsorption with antibody.

    PubMed

    Prai-In, Yingrak; Boonthip, Chatchai; Rutnakornpituk, Boonjira; Wichai, Uthai; Montembault, Véronique; Pascual, Sagrario; Fontaine, Laurent; Rutnakornpituk, Metha

    2016-10-01

    Surface modification of magnetic nanoparticle (MNP) with poly(ethylene oxide)-block-poly(2-vinyl-4,4-dimethylazlactone) (PEO-b-PVDM) diblock copolymers and its application as recyclable magnetic nano-support for adsorption with antibody were reported herein. PEO-b-PVDM copolymers were first synthesized via a reversible addition-fragmentation chain-transfer (RAFT) polymerization using poly(ethylene oxide) chain-transfer agent as a macromolecular chain transfer agent to mediate the RAFT polymerization of VDM. They were then grafted on amino-functionalized MNP by coupling with some azlactone rings of the PVDM block to form magnetic nanoclusters with tunable cluster size. The nanocluster size could be tuned by adjusting the chain length of the PVDM block. The nanoclusters were successfully used as efficient and recyclable nano-supports for adsorption with anti-rabbit IgG antibody. They retained higher than 95% adsorption of the antibody during eight adsorption-separation-desorption cycles, indicating the potential feasibility in using this novel hybrid nanocluster as recyclable support in cell separation applications. PMID:27287124

  3. Ethylene glycol

    Integrated Risk Information System (IRIS)

    Ethylene glycol ; CASRN 107 - 21 - 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 Noncarcinogenic E

  4. Ethylene diamine

    Integrated Risk Information System (IRIS)

    Ethylene diamine ; CASRN 107 - 15 - 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

  5. A process concept for the production of benzene-ethylene-SNG from coal using flash hydropyrolysis technology

    NASA Astrophysics Data System (ADS)

    Greene, M. I.; Ladelfa, C. J.; Bivacca, S. J.

    1980-05-01

    Flash hydropyrolysis (FHP) of coal is an emerging technology for the direct production of methane, ethane and BTX in a single-stage, high throughput reactor. The FHP technique involves the short residence time (1-2 seconds), rapid heatup of coal in a dilute-phase, transport reactor. When integrated into an overall, grass-roots conversion complex, the FHP technique can be utilized to generate a product consisting of SNG, ethylene/propylene, benzene and Fischer-Tropsch-based alcohols. This paper summarizes the process engineering and economics of conceptualized facility based on an FHP reactor operation with a lignitic coal. The plant is hypothetically sited near the extensive lignite fields located in the Texas region of the United States. Utilizing utility-financing methods for the costing of SNG, and selling the chemicals cogenerated at petrochemical market prices, the 20-year average SNG cost has been computed to vary between $3-4/MM Btu, depending upon the coal costs, interest rates, debt/equity ratio, coproduct chemicals prices, etc.

  6. Graphene oxide and H2 production from bioelectrochemical graphite oxidation.

    PubMed

    Lu, Lu; Zeng, Cuiping; Wang, Luda; Yin, Xiaobo; Jin, Song; Lu, Anhuai; Jason Ren, Zhiyong

    2015-01-01

    Graphene oxide (GO) is an emerging material for energy and environmental applications, but it has been primarily produced using chemical processes involving high energy consumption and hazardous chemicals. In this study, we reported a new bioelectrochemical method to produce GO from graphite under ambient conditions without chemical amendments, value-added organic compounds and high rate H2 were also produced. Compared with abiotic electrochemical electrolysis control, the microbial assisted graphite oxidation produced high rate of graphite oxide and graphene oxide (BEGO) sheets, CO2, and current at lower applied voltage. The resultant electrons are transferred to a biocathode, where H2 and organic compounds are produced by microbial reduction of protons and CO2, respectively, a process known as microbial electrosynthesis (MES). Pseudomonas is the dominant population on the anode, while abundant anaerobic solvent-producing bacteria Clostridium carboxidivorans is likely responsible for electrosynthesis on the cathode. Oxygen production through water electrolysis was not detected on the anode due to the presence of facultative and aerobic bacteria as O2 sinkers. This new method provides a sustainable route for producing graphene materials and renewable H2 at low cost, and it may stimulate a new area of research in MES. PMID:26573014

  7. Graphene oxide and H2 production from bioelectrochemical graphite oxidation

    NASA Astrophysics Data System (ADS)

    Lu, Lu; Zeng, Cuiping; Wang, Luda; Yin, Xiaobo; Jin, Song; Lu, Anhuai; Jason Ren, Zhiyong

    2015-11-01

    Graphene oxide (GO) is an emerging material for energy and environmental applications, but it has been primarily produced using chemical processes involving high energy consumption and hazardous chemicals. In this study, we reported a new bioelectrochemical method to produce GO from graphite under ambient conditions without chemical amendments, value-added organic compounds and high rate H2 were also produced. Compared with abiotic electrochemical electrolysis control, the microbial assisted graphite oxidation produced high rate of graphite oxide and graphene oxide (BEGO) sheets, CO2, and current at lower applied voltage. The resultant electrons are transferred to a biocathode, where H2 and organic compounds are produced by microbial reduction of protons and CO2, respectively, a process known as microbial electrosynthesis (MES). Pseudomonas is the dominant population on the anode, while abundant anaerobic solvent-producing bacteria Clostridium carboxidivorans is likely responsible for electrosynthesis on the cathode. Oxygen production through water electrolysis was not detected on the anode due to the presence of facultative and aerobic bacteria as O2 sinkers. This new method provides a sustainable route for producing graphene materials and renewable H2 at low cost, and it may stimulate a new area of research in MES.

  8. Graphene oxide and H2 production from bioelectrochemical graphite oxidation

    PubMed Central

    Lu, Lu; Zeng, Cuiping; Wang, Luda; Yin, Xiaobo; Jin, Song; Lu, Anhuai; Jason Ren, Zhiyong

    2015-01-01

    Graphene oxide (GO) is an emerging material for energy and environmental applications, but it has been primarily produced using chemical processes involving high energy consumption and hazardous chemicals. In this study, we reported a new bioelectrochemical method to produce GO from graphite under ambient conditions without chemical amendments, value-added organic compounds and high rate H2 were also produced. Compared with abiotic electrochemical electrolysis control, the microbial assisted graphite oxidation produced high rate of graphite oxide and graphene oxide (BEGO) sheets, CO2, and current at lower applied voltage. The resultant electrons are transferred to a biocathode, where H2 and organic compounds are produced by microbial reduction of protons and CO2, respectively, a process known as microbial electrosynthesis (MES). Pseudomonas is the dominant population on the anode, while abundant anaerobic solvent-producing bacteria Clostridium carboxidivorans is likely responsible for electrosynthesis on the cathode. Oxygen production through water electrolysis was not detected on the anode due to the presence of facultative and aerobic bacteria as O2 sinkers. This new method provides a sustainable route for producing graphene materials and renewable H2 at low cost, and it may stimulate a new area of research in MES. PMID:26573014

  9. Ethylene Response Factor TERF1, Regulated by ETHYLENE-INSENSITIVE3-like Factors, Functions in Reactive Oxygen Species (ROS) Scavenging in Tobacco (Nicotiana tabacum L.).

    PubMed

    Zhang, Hongbo; Li, Ang; Zhang, Zhijin; Huang, Zejun; Lu, Pingli; Zhang, Dingyu; Liu, Xinmin; Zhang, Zhong-Feng; Huang, Rongfeng

    2016-01-01

    The phytohormone ethylene plays a crucial role in the production and accumulation of reactive oxygen species (ROS) in plants under stress conditions. Ethylene response factors (ERFs) are important ethylene-signaling regulators functioning in plant defense responses against biotic and abiotic stresses. However, the roles of ERFs during plant adapting to ROS stress have not yet been well documented. Our studies previously reported that a tomato ERF transcription factor TERF1 functions in the regulation of plant ethylene responses and stress tolerance. Here, we report our findings regarding the roles of TERF1 in ROS scavenging. In this study, we revealed that the transcription of TERF1 is regulated by upstream EIN3-like (EIN3, ethylene-insensitive 3) regulators LeEIL3 and LeEIL4 in tomato (Solanum lycopersicum), and is also inducible by exogenous applied ROS-generating reagents. Ectopic expression of TERF1 in tobacco promoted the expression of genes involved in oxidative stress responses, including carbonic anhydrase functioning in hypersensitive defense, catalase and glutathione peroxidase catalyzing oxidative reactions, and GDP-D-mannose pyrophosphorylase functioning in ascorbic acid biosynthesis, reduced the ROS content induced by ethylene treatment, and enhanced stress tolerance of tobacco seedlings to hydrogen peroxide (H2O2). Cumulatively, these findings suggest that TERF1 is an ethylene inducible factor regulating ROS scavenging during stress responses. PMID:27435661

  10. Ethylene Response Factor TERF1, Regulated by ETHYLENE-INSENSITIVE3-like Factors, Functions in Reactive Oxygen Species (ROS) Scavenging in Tobacco (Nicotiana tabacum L.)

    PubMed Central

    Zhang, Hongbo; Li, Ang; Zhang, Zhijin; Huang, Zejun; Lu, Pingli; Zhang, Dingyu; Liu, Xinmin; Zhang, Zhong-Feng; Huang, Rongfeng

    2016-01-01

    The phytohormone ethylene plays a crucial role in the production and accumulation of reactive oxygen species (ROS) in plants under stress conditions. Ethylene response factors (ERFs) are important ethylene-signaling regulators functioning in plant defense responses against biotic and abiotic stresses. However, the roles of ERFs during plant adapting to ROS stress have not yet been well documented. Our studies previously reported that a tomato ERF transcription factor TERF1 functions in the regulation of plant ethylene responses and stress tolerance. Here, we report our findings regarding the roles of TERF1 in ROS scavenging. In this study, we revealed that the transcription of TERF1 is regulated by upstream EIN3-like (EIN3, ethylene-insensitive 3) regulators LeEIL3 and LeEIL4 in tomato (Solanum lycopersicum), and is also inducible by exogenous applied ROS-generating reagents. Ectopic expression of TERF1 in tobacco promoted the expression of genes involved in oxidative stress responses, including carbonic anhydrase functioning in hypersensitive defense, catalase and glutathione peroxidase catalyzing oxidative reactions, and GDP-D-mannose pyrophosphorylase functioning in ascorbic acid biosynthesis, reduced the ROS content induced by ethylene treatment, and enhanced stress tolerance of tobacco seedlings to hydrogen peroxide (H2O2). Cumulatively, these findings suggest that TERF1 is an ethylene inducible factor regulating ROS scavenging during stress responses. PMID:27435661

  11. Involvement of ethylene in gibberellic acid-induced sulfur assimilation, photosynthetic responses, and alleviation of cadmium stress in mustard.

    PubMed

    Masood, Asim; Khan, M Iqbal R; Fatma, Mehar; Asgher, Mohd; Per, Tasir S; Khan, Nafees A

    2016-07-01

    The role of gibberellic acid (GA) or sulfur (S) in stimulation of photosynthesis is known. However, information on the involvement of ethylene in GA-induced photosynthetic responses and cadmium (Cd) tolerance is lacking. This work shows that ethylene is involved in S-assimilation, photosynthetic responses and alleviation of Cd stress by GA in mustard (Brassica juncea L.). Plants grown with 200 mg Cd kg(-1) soil were less responsive to ethylene despite high ethylene evolution and showed photosynthetic inhibition. Plants receiving 10 μM GA spraying plus 100 mg S kg(-1) soil supplementation exhibited increased S-assimilation and photosynthetic responses under Cd stress. Application of GA plus S decreased oxidative stress of plants grown with Cd and limited stress ethylene formation to the range suitable for promoting sulfur use efficiency (SUE), glutathione (GSH) production and photosynthesis. The role of ethylene in GA-induced S-assimilation and reversal of photosynthetic inhibition by Cd was substantiated by inhibiting ethylene biosynthesis with the use of aminoethoxyvinylglycine (AVG). The suppression of S-assimilation and photosynthetic responses by inhibiting ethylene in GA plus S treated plants under Cd stress indicated the involvement of ethylene in GA-induced S-assimilation and Cd stress alleviation. The outcome of the study is important to unravel the interaction between GA and ethylene and their role in Cd tolerance in plants. PMID:26998941

  12. Study on ion conductivity and crystallinity of composite polymer electrolytes based on poly(ethylene oxide)/poly(acrylonitrile) containing nano-sized Al2O3 fillers.

    PubMed

    Kim, Mingyeong; Lee, Lyungyu; Jung, Yongju; Kim, Seok

    2013-12-01

    In this paper, composite polymer electrolytes were prepared by a blend of poly(ethylene oxide) (PEO) and poly(acrylonitrile) (PAN) as a polymer matrix, ethylene carbonate as a plasticizer, LiClO4 as a salt, and by containing a different content of nano-sized Al2O3. The composite films were prepared by using the solution casting method. The crystallinity and ionic conductivity of the polymer electrolytes was investigated using X-ray diffraction (XRD) and AC impedance method, respectively. The morphology of composite polymer electrolyte film was analyzed by SEM method. From the experimental results, by increasing the Al2O3 content, the crystallinity of PEO was reduced, and the ionic conductivity was increased. In particular, by a doping of 15 wt.% Al2O3 in PEO/PAN polymer blend, the CPEs showed the superior ionic conductivity. However, when Al2O3 content exceeds 15 wt.%, the ionic conductivity was decreased. From the surface morphology, it was concluded that the ionic conductivity was decreased because the CPEs showed a heterogenous morphology due to immiscibility or aggregation of the ceramic filler within the polymer matrix. PMID:24266154

  13. Immobilization of poly(ɛ-caprolactone)-poly(ethylene oxide)-poly(ɛ-caprolactone) triblock copolymer on poly(lactide- co-glycolide) surface and dual biofunctional effects

    NASA Astrophysics Data System (ADS)

    Zhu, Aiping; Lu, Ping; Wu, Hao

    2007-01-01

    Poly(ɛ-caprolactone)-poly(ethylene oxide)-poly(ɛ-caprolactone) (PCL-PEG-PCL) triblock copolymer was covalently immobilized onto poly(lactide- co-glycolide) (PLGA) surface with the precursor of photopolymerizable and biodegradable PCL-PEG-PCL diacrylates. Argon plasma technique was exploited to obtain hydrophilic PLGA surface (HPLGA). The surface properties were characterized by Water contact angle and X-ray photoelectron spectroscopy (XPS) techniques. PCL-PEG-PCL surface modified hydrophobic PLGA and hydrophilic PLGA results in different surface physicochemical properties. PCL-PEG-PCL modified hydrophobic PLGA surface (PLGA-PCL-PEG-PCL) demonstrates excellent inhibition of platelet adhesion and activation; while PCL-PEG-PCL modified hydrophilic PLGA surface (HPLGA-PCL-PEG-PCL) results in good cytocompatibility. The possible mechanism was discussed and the driven force was ascribed to the different assembly behavior of PCL-PEG-PCL on PLGA surface dependant on the hydrophilic/hydrophobic property of PLGA. This simple and effective surface engineering method is also suitable for the other biomaterials such as polyurethane (PU), silicon rubber and poly(ethylene terephthalate) (PET) to obtain the enhanced biocompatibility.

  14. The Mechanism of Ethylene Signaling Induced by Endophytic Fungus Gilmaniella sp. AL12 Mediating Sesquiterpenoids Biosynthesis in Atractylodes lancea

    PubMed Central

    Yuan, Jie; Sun, Kai; Deng-Wang, Meng-Yao; Dai, Chuan-Chao

    2016-01-01

    Ethylene, the first known gaseous phytohormone, is involved in plant growth, development as well as responses to environmental signals. However, limited information is available on the role of ethylene in endophytic fungi induced secondary metabolites biosynthesis. Atractylodes lancea is a traditional Chinese herb, and its quality depends on the main active compounds sesquiterpenoids. This work showed that the endophytic fungus Gilmaniella sp. AL12 induced ethylene production in Atractylodes lancea. Pre-treatment of plantlets with ethylene inhibiter aminooxyacetic acid (AOA) suppressed endophytic fungi induced accumulation of ethylene and sesquiterpenoids. Plantlets were further treated with AOA, salicylic acid (SA) biosynthesis inhibitor paclobutrazol (PAC), jasmonic acid inhibitor ibuprofen (IBU), hydrogen peroxide (H2O2) scavenger catalase (CAT), nitric oxide (NO)-specific scavenger 2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt (cPTIO). With endophytic fungi inoculation, IBU or PAC did not inhibit ethylene production, and JA and SA generation were suppressed by AOA, showing that ethylene may act as an upstream signal of JA and SA pathway. With endophytic fungi inoculation, CAT or cPTIO suppressed ethylene production, and H2O2 or NO generation was not affected by 1-aminocyclopropane-1-carboxylic acid (ACC), showing that ethylene may act as a downstream signal of H2O2 and NO pathway. Then, plantlets were treated with ethylene donor ACC, JA, SA, H2O2, NO donor sodium nitroprusside (SNP). Exogenous ACC could trigger JA and SA generation, whereas exogenous JA or SA did not affect ethylene production, and the induced sesquiterpenoids accumulation triggered by ACC was partly suppressed by IBU and PAC, showing that ethylene acted as an upstream signal of JA and SA pathway. Exogenous ACC did not affect H2O2 or NO generation, whereas exogenous H2O2 and SNP induced ethylene production, and the induced sesquiterpenoids accumulation

  15. The Mechanism of Ethylene Signaling Induced by Endophytic Fungus Gilmaniella sp. AL12 Mediating Sesquiterpenoids Biosynthesis in Atractylodes lancea.

    PubMed

    Yuan, Jie; Sun, Kai; Deng-Wang, Meng-Yao; Dai, Chuan-Chao

    2016-01-01

    Ethylene, the first known gaseous phytohormone, is involved in plant growth, development as well as responses to environmental signals. However, limited information is available on the role of ethylene in endophytic fungi induced secondary metabolites biosynthesis. Atractylodes lancea is a traditional Chinese herb, and its quality depends on the main active compounds sesquiterpenoids. This work showed that the endophytic fungus Gilmaniella sp. AL12 induced ethylene production in Atractylodes lancea. Pre-treatment of plantlets with ethylene inhibiter aminooxyacetic acid (AOA) suppressed endophytic fungi induced accumulation of ethylene and sesquiterpenoids. Plantlets were further treated with AOA, salicylic acid (SA) biosynthesis inhibitor paclobutrazol (PAC), jasmonic acid inhibitor ibuprofen (IBU), hydrogen peroxide (H2O2) scavenger catalase (CAT), nitric oxide (NO)-specific scavenger 2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt (cPTIO). With endophytic fungi inoculation, IBU or PAC did not inhibit ethylene production, and JA and SA generation were suppressed by AOA, showing that ethylene may act as an upstream signal of JA and SA pathway. With endophytic fungi inoculation, CAT or cPTIO suppressed ethylene production, and H2O2 or NO generation was not affected by 1-aminocyclopropane-1-carboxylic acid (ACC), showing that ethylene may act as a downstream signal of H2O2 and NO pathway. Then, plantlets were treated with ethylene donor ACC, JA, SA, H2O2, NO donor sodium nitroprusside (SNP). Exogenous ACC could trigger JA and SA generation, whereas exogenous JA or SA did not affect ethylene production, and the induced sesquiterpenoids accumulation triggered by ACC was partly suppressed by IBU and PAC, showing that ethylene acted as an upstream signal of JA and SA pathway. Exogenous ACC did not affect H2O2 or NO generation, whereas exogenous H2O2 and SNP induced ethylene production, and the induced sesquiterpenoids accumulation

  16. Real-time monitoring of endogenous lipid peroxidation by exhaled ethylene in patients undergoing cardiac surgery.

    PubMed

    Cristescu, Simona M; Kiss, Rudolf; Hekkert, Sacco te Lintel; Dalby, Miles; Harren, Frans J M; Risby, Terence H; Marczin, Nandor

    2014-10-01

    Pulmonary and systemic organ injury produced by oxidative stress including lipid peroxidation is a fundamental tenet of ischemia-reperfusion injury, inflammatory response to cardiac surgery, and cardiopulmonary bypass (CPB) but is not routinely measured in a surgically relevant time frame. To initiate a paradigm shift toward noninvasive and real-time monitoring of endogenous lipid peroxidation, we have explored pulmonary excretion and dynamism of exhaled breath ethylene during cardiac surgery to test the hypothesis that surgical technique and ischemia-reperfusion triggers lipid peroxidation. We have employed laser photoacoustic spectroscopy to measure real-time trace concentrations of ethylene from the patient breath and from the CPB machine. Patients undergoing aortic or mitral valve surgery-requiring CPB (n = 15) or off-pump coronary artery bypass surgery (OPCAB) (n = 7) were studied. Skin and tissue incision by diathermy caused striking (> 30-fold) increases in exhaled ethylene resulting in elevated levels until CPB. Gaseous ethylene in the CPB circuit was raised upon the establishment of CPB (> 10-fold) and decreased over time. Reperfusion of myocardium and lungs did not appear to enhance ethylene levels significantly. During OPCAB surgery, we have observed increased ethylene in 16 of 30 documented reperfusion events associated with coronary and aortic anastomoses. Therefore, novel real-time monitoring of endogenous lipid peroxidation in the intraoperative setting provides unparalleled detail of endogenous and surgery-triggered production of ethylene. Diathermy and unprotected regional myocardial ischemia and reperfusion are the most significant contributors to increased ethylene. PMID:25128523

  17. Real-time monitoring of endogenous lipid peroxidation by exhaled ethylene in patients undergoing cardiac surgery

    PubMed Central

    Cristescu, Simona M.; Kiss, Rudolf; te Lintel Hekkert, Sacco; Dalby, Miles; Harren, Frans J. M.; Risby, Terence H.

    2014-01-01

    Pulmonary and systemic organ injury produced by oxidative stress including lipid peroxidation is a fundamental tenet of ischemia-reperfusion injury, inflammatory response to cardiac surgery, and cardiopulmonary bypass (CPB) but is not routinely measured in a surgically relevant time frame. To initiate a paradigm shift toward noninvasive and real-time monitoring of endogenous lipid peroxidation, we have explored pulmonary excretion and dynamism of exhaled breath ethylene during cardiac surgery to test the hypothesis that surgical technique and ischemia-reperfusion triggers lipid peroxidation. We have employed laser photoacoustic spectroscopy to measure real-time trace concentrations of ethylene from the patient breath and from the CPB machine. Patients undergoing aortic or mitral valve surgery-requiring CPB (n = 15) or off-pump coronary artery bypass surgery (OPCAB) (n = 7) were studied. Skin and tissue incision by diathermy caused striking (>30-fold) increases in exhaled ethylene resulting in elevated levels until CPB. Gaseous ethylene in the CPB circuit was raised upon the establishment of CPB (>10-fold) and decreased over time. Reperfusion of myocardium and lungs did not appear to enhance ethylene levels significantly. During OPCAB surgery, we have observed increased ethylene in 16 of 30 documented reperfusion events associated with coronary and aortic anastomoses. Therefore, novel real-time monitoring of endogenous lipid peroxidation in the intraoperative setting provides unparalleled detail of endogenous and surgery-triggered production of ethylene. Diathermy and unprotected regional myocardial ischemia and reperfusion are the most significant contributors to increased ethylene. PMID:25128523

  18. Ethylene and senescence in petals of tradescantia.

    PubMed

    Suttle, J C; Kende, H

    1978-08-01

    Flowers of Tradescantia (clone O2) which are ephemeral, produce ethylene during senescence with the maximum rates occurring during the initial period of fading. Senescing isolated petals produce ethylene in a similar manner, exhibit a loss of membrane semipermeability, and exogenous ethylene hastens the onset as well as the subsequent rate of this loss. The aminoethoxy analog of 0.1 millimolar rhizobitoxine completely inhibits ethylene production by isolated petals but only partially the loss of membrane semipermeability. Isolated petals acquire a sensitivity to ethylene as they mature, becoming fully sensitive on the day of anthesis. PMID:16660498

  19. Effect of Solution Conditions on the Nanoscale Intermolecular Interactions Between Human Serum Albumin and Low Grafting Density Surfaces of Poly(ethylene oxide)

    NASA Astrophysics Data System (ADS)

    Rixman, Monica; Macias, Celia; Dean, Delphine; Ortiz, Christine

    2003-03-01

    The first step in the biological rejection response to an implanted blood-contacting biomaterial is the non-covalent adsorption of proteins onto the surface, which triggers a cascade reaction ultimately resulting in thrombus formation. Using the technique of high resolution force spectroscopy, we have quantified the nonspecific intermolecular forces between fatty acid-complexed human serum albumin (HSA) covalently attached to a cantilever probe tip and individual end-grafted poly(ethylene oxide) mushrooms. In order to help elucidate the molecular origins of the constituent forces (e.g. steric, electrostatic, van der Waals), experiments were performed varying both the solution environmental conditions (e.g. ionic strength, removal of the bound fatty acids, and the addition of the antihydrophobic agent isopropanol), and the probe deflection rate.

  20. Rheological kinetics of thermo-sensitive supramolecular assemblies from poly( N-isopropyl acrylamide) and adenine-functionalized poly(ethylene oxide) stabilized by complementary multiple hydrogen bonds

    NASA Astrophysics Data System (ADS)

    Cui, Hui-Wang; Kuo, Shiao-Wei

    2014-05-01

    In this study, we synthesized a poly( N-isopropylacrylamide) (PNIPAm) through the polymerization of N-isopropylacrylamide in distilled water with azodiisobutyronitrile as the initiator and a bisadenine-functionalized poly(ethylene oxide) (A-PEO-A) from the reaction of adenine with a difunctionalized toluenesulfonyl-PEO. When blended together in distilled water, PNIPAm and A-PEO-A formed supramolecular aggregates stabilized through complementary multiple hydrogen bonds between the amide groups of PNIPAm and the adenine units of A-PEO-A. Agrawal integral equation and rheometry revealed the rheological kinetics of supramolecular assemblies, which were influenced significantly by the spherical micelles, large associated aggregates of spherical micelles, network structures, and toroid structures formed in aqueous solutions.

  1. Isothermal growth, thickening and melting of poly(ethylene-oxide) single crystals in the bulk. III. Bilayer crystals and the effect of chain ends

    NASA Astrophysics Data System (ADS)

    Kovacs, A. J.; Straupe, C.

    1980-02-01

    Growth, thickening and melting of poly(ethylene-oxide) single crystals, grown from the melt, have been investigated using three fractions of nearly the same chain length. The data are compared to and complement previous work, which is briefly recalled. The new results mainly concern the behavior of siamese twin-lamellae simultaneously grown from the same seed, modelling shish kebabs. On the other hand, the impact of a diphenyl group at one chain end is investigated in a systematic manner. The results show that these small modifications in the constitution of the crystals and in one of the chain ends give rise to rather large and often spectacular effects. The implications of these are discussed in terms of the detailed molecular conformations and mobility in the crystal lattice, in connection with current understanding of chain folding in lamellar polymer crystals.

  2. Enhanced retention of polymer physical characteristics and mechanical strength of 70:30 poly(L-lactide-co-D,L-lactide) after ethylene oxide sterilization.

    PubMed

    McManus, Anastasia J; Moser, Rodney C; Dabkowski, Rhiannon B; Thomas, Kevin A

    2007-08-01

    This study examined the effect of ethylene oxide (EtO) and electron beam (e-beam) irradiation on the properties of 70:30 poly(L-lactide-co-D,L-lactide). The effects of sterilization upon the polymer physical characteristics and strength retention of the material were examined, both initially and after being subjected to real time ageing. Commercially available 70:30 poly(L-lactide-co-D,L-lactide) material was fabricated into rectangular, cylindrical, screw, and sheet designs, and tested in compression, shear, or tension. Sterilization of 70:30 poly(L-lactide-co-D,L-lactide) by ethylene oxide had a nearly negligible effect on the physical properties of the polymer, regardless of specimen size or manufacturing technique. The molecular weight and inherent viscosity of the specimens decreased by approximately 3% after sterilization by EtO. However, sterilization of 70:30 poly(L-lactide-co-D,L-lactide) by e-beam irradiation resulted in immediate changes to some of the physical properties of the polymer. Specimens sterilized by e-beam irradiation displayed an immediate decrease in inherent viscosity of approximately 67% as compared to the respective nonsterile samples. The immediate decrease in inherent viscosity and molecular weight with e-beam irradiation required approximately 39 weeks of real time ageing of the EtO sterilized parts. At all time points investigated in the present study, the strength retention of the EtO sterilized devices equaled or exceeded that of the e-beam irradiated samples. PMID:17238162

  3. Highly mobile segments in crystalline poly(ethylene oxide)8:NaPF6 electrolytes studied by solid-state NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Luo, Huan; Liang, Xinmiao; Wang, Liying; Zheng, Anmin; Liu, Chaoyang; Feng, Jiwen

    2014-02-01

    Two types of high-crystallinity poly(ethylene oxide)/NaPF6 electrolytes with ethylene oxide (EO)/Na molar ratios of 8:1 and 6:1, termed as PEO8:NaPF6 and PEO6:NaPF6 with Mw = 6000 g mol-1 were prepared, and their ionic conductivity, structure, and segmental motions were investigated and compared. PEO8:NaPF6 polymer electrolyte exhibits the room-temperature ionic conductivity 7.7 × 10-7 S cm-1 which is about five times higher than the PEO6:NaPF6. By variable-temperature measurements of static powder spectra and 1H spin-lattice relaxation time in rotation frame (1H T1ρ), we demonstrate that crystalline segments are more highly mobile in the crystalline PEO8:NaPF6 with higher ionic conductivity than in the PEO6:NaPF6 with lower ionic conductivity. The large-angle reorientation motion of polymer segments in the PEO8:NaPF6 onsets at lower temperature (˜233 K) with a low activation energy 0.31 eV that is comparable with that of the pure PEO crystal. Whereas, the large-angle reorientation motion of polymer segments in the PEO6:NaPF6 starts around 313 K with a high activation energy of 0.91 eV. As a result of the temperature-enhanced large-angle reorientations, the 13C static powder lineshape changes markedly from a low-temperature wide pattern with apparent principal values of chemical shift δ33 < δ22 < δ11 to a high-temperature narrow pattern of uniaxial chemical shift anisotropy δ33 > δ22 (δ11). It is suggested that the segmental motion in crystalline PEO-salt complex promotes ionic conductivity.

  4. Hygroscopic Properties of Oxidation Products of Terpenes

    NASA Astrophysics Data System (ADS)

    Lodhi, N. A.; Mozurkewich, M.

    2009-05-01

    To understand the hygroscopic growth factor (HGF) of secondary organic aerosol (SOA) formed by the oxidation of terpenes, a series of seeded and nucleation experiments were conducted at the York University smog chamber facility. Oxidation of terpenes by OH was carried out in a dry chamber (RH˜5%). In nucleation experiments particles formed were pure organic and their hygroscopic growth factor was measured as function of relative humidity by using a tandem differential mobility analyzer (HTDMA). Humidograms of these particles don't show any deliquescence or efflorescence. Humidograms of pure organic particles formed by the oxidation products of β-pinene show slight but smooth take up of water while particles formed by α-pinene and δ3-carene exhibit very little or no water uptake. Experimental results were fitted with an empirical equation and the hygroscopicity parameter for the particles formed by β-pinene was found to be 0.019±0.009. To examine the interaction of organic and inorganic phases, monodisperse ammonium sulfate seed particles injected into the smog chamber were allowed to undergo condensational growth due to partitioning of terpenes oxidation products from the gas phase. Humidograms of seeded particles show both smooth hygroscopic growth and deliquescence. These experimental results were fitted with a numerical model that accounts for water uptake by both phases and for the gradual dissolution of ammonium sulfate. The results show that volume additivity is a reasonable approximation for this system and that HTDMA results can be inverted to obtain the organic hygroscopicity parameter and the relative amounts of organic and inorganic material

  5. Bisphenol A treatment by the hot persulfate process: oxidation products and acute toxicity.

    PubMed

    Olmez-Hanci, Tugba; Arslan-Alaton, Idil; Genc, Bora

    2013-12-15

    In this study, a thermally activated persulfate oxidation process was investigated to treat aqueous Bisphenol A (BPA) solution. The effect of temperature (40-50-60-70°C), initial pH (pH=3.0, 6.5, 9.0 and 11.0) and persulfate concentration (0-20mM) on bisphenol A (BPA) and TOC removals was examined. The activation energy for hot persulfate oxidation of BPA was calculated as 184 ± 12 kJ/mol. Acidic and neutral pH values were more favorable for BPA oxidation than basic pH values. TOC removals did not exhibit a specific pattern with varying initial pHs. Gas chromatography/mass spectrometry was employed to identify oxidation products. Several aromatic and a few aliphatic compounds could be detected including benzaldehyde, p-isopropenyl phenol, 2,3-dimethyl benzoic acid, 3-hydroxy-4-methyl-benzoic acid, ethylene glycol monoformate and succinic acid. Acute toxicity tests conducted with Vibrio fischeri indicated that the inhibitory effect of 88 μM BPA solution originally being 58%, increased to 84% after 30 min and decreased to 22% after 90 min hot persulfate treatment that could be attributed to the formation and subsequent disappearance of oxidation products. PMID:23433897

  6. A spectroscopic study of ethylene destruction and by-product generation using a three-stage atmospheric packed-bed plasma reactor

    SciTech Connect

    Huebner, M.; Roepcke, J.; Guaitella, O.; Rousseau, A.

    2013-07-21

    Using a three-stage dielectric packed-bed plasma reactor at atmospheric pressure, the destruction of ethylene, a typical volatile organic compound, and the generation of major by-products have been studied by means of Fourier Transform Infrared Spectroscopy. A test gas mixture air at a gas flow of 1 slm containing 0.12% humidity with 0.1% ethylene has been used. In addition to the fragmentation of the precursor gas, the evolution of the concentration of ten stable reaction products, CO, CO{sub 2}, O{sub 3}, NO{sub 2}, N{sub 2}O, HCN, H{sub 2}O, HNO{sub 3}, CH{sub 2}O, and CH{sub 2}O{sub 2} has been monitored. The concentrations of the by-products range between 5 ppm, in the case of NO{sub 2}, and 1200 ppm, for H{sub 2}O. By the application of three sequentially working discharge cells at a frequency of f = 4 kHz and voltage values between 9 and 12 kV, a nearly complete decomposition of C{sub 2}H{sub 4} could be achieved. Furthermore, the influence of the specific energy deposition (SED) on the destruction process has been studied and the maximum value of SED was about 900 J l{sup -1}. The value of the characteristic energy {beta}, characterizing the energy efficiency of the ethylene destruction in the reactor, was found to be 330 J l{sup -1}. It was proven that the application of three reactor stages suppresses essentially the production of harmful by-products as formaldehyde, formic acid, and NO{sub 2} compared to the use of only one or two stages. Based on the multi-component detection, the carbon balance of the plasma chemical conversion of ethylene has been analyzed. The dependence of the fragmentation efficiencies of ethylene (R{sub F}(C{sub 2}H{sub 4}) = 5.5 Multiplication-Sign 10{sup 19} molecules J{sup -1}) and conversion efficiencies to the produced molecular species (R{sub C} = (0.1-3) Multiplication-Sign 10{sup 16} molecules J{sup -1}) on the discharge conditions could be estimated in the multistage plasma reactor.

  7. A spectroscopic study of ethylene destruction and by-product generation using a three-stage atmospheric packed-bed plasma reactor

    NASA Astrophysics Data System (ADS)

    Hübner, M.; Guaitella, O.; Rousseau, A.; Röpcke, J.

    2013-07-01

    Using a three-stage dielectric packed-bed plasma reactor at atmospheric pressure, the destruction of ethylene, a typical volatile organic compound, and the generation of major by-products have been studied by means of Fourier Transform Infrared Spectroscopy. A test gas mixture air at a gas flow of 1 slm containing 0.12% humidity with 0.1% ethylene has been used. In addition to the fragmentation of the precursor gas, the evolution of the concentration of ten stable reaction products, CO, CO2, O3, NO2, N2O, HCN, H2O, HNO3, CH2O, and CH2O2 has been monitored. The concentrations of the by-products range between 5 ppm, in the case of NO2, and 1200 ppm, for H2O. By the application of three sequentially working discharge cells at a frequency of f = 4 kHz and voltage values between 9 and 12 kV, a nearly complete decomposition of C2H4 could be achieved. Furthermore, the influence of the specific energy deposition (SED) on the destruction process has been studied and the maximum value of SED was about 900 J l-1. The value of the characteristic energy β, characterizing the energy efficiency of the ethylene destruction in the reactor, was found to be 330 J l-1. It was proven that the application of three reactor stages suppresses essentially the production of harmful by-products as formaldehyde, formic acid, and NO2 compared to the use of only one or two stages. Based on the multi-component detection, the carbon balance of the plasma chemical conversion of ethylene has been analyzed. The dependence of the fragmentation efficiencies of ethylene (RF(C2H4) = 5.5 × 1019 molecules J-1) and conversion efficiencies to the produced molecular species (RC = (0.1-3) × 1016 molecules J-1) on the discharge conditions could be estimated in the multistage plasma reactor.

  8. Participation of ethylene in gravitropism

    NASA Technical Reports Server (NTRS)

    Harrison, M.; Pickard, B. G.

    1984-01-01

    In shoots of many plants, of which tomato (Lycopersicon esculentum Mill.) is an example, ethylene production is substantially increased during gravitropism. As a first step toward elucidating the role of ethylene in gravitropism, detailed time courses of ethylene production in isolated hypocotyl segments and whole plants were measured for gravistimulated and upright tomato seedlings. In the first experiment, seedlings were set upright or laid horizontal and then, at 15 min intervals, sets of hypocotyls were excised and sealed into gas tight vials. A steady long term rise in ethylene production begins after 15 min gravistimulation. It is possible that this increase is a consequence of the accumulation of indoleacetic acid (IAA) in the lower tissue of the hypocotyle. In a second kind of experiment, whole seedlings were enclosed in sealed chambers and air samples were withdrawn at 5 min intervals. Stimulated seedlings produced more ethylene than controls during the first 5 min interval, but not appreciably more during the second. This suggests the possibility that the ethylene production induced during the first 5 min occurs immediately rather than after a lag, and thus much too soon to be controlled by redistribution of IAA.

  9. Modeling of nitrous oxide production by autotrophic ammonia-oxidizing bacteria with multiple production pathways.

    PubMed

    Ni, Bing-Jie; Peng, Lai; Law, Yingyu; Guo, Jianhua; Yuan, Zhiguo

    2014-04-01

    Autotrophic ammonia oxidizing bacteria (AOB) have been recognized as a major contributor to N2O production in wastewater treatment systems. However, so far N2O models have been proposed based on a single N2O production pathway by AOB, and there is still a lack of effective approach for the integration of these models. In this work, an integrated mathematical model that considers multiple production pathways is developed to describe N2O production by AOB. The pathways considered include the nitrifier denitrification pathway (N2O as the final product of AOB denitrification with NO2(-) as the terminal electron acceptor) and the hydroxylamine (NH2OH) pathway (N2O as a byproduct of incomplete oxidation of NH2OH to NO2(-)). In this model, the oxidation and reduction processes are modeled separately, with intracellular electron carriers introduced to link the two types of processes. The model is calibrated and validated using experimental data obtained with two independent nitrifying cultures. The model satisfactorily describes the N2O data from both systems. The model also predicts shifts of the dominating pathway at various dissolved oxygen (DO) and nitrite levels, consistent with previous hypotheses. This unified model is expected to enhance our ability to predict N2O production by AOB in wastewater treatment systems under varying operational conditions. PMID:24571180

  10. Reforming of oxygenates for H2 production: correlating reactivity of ethylene glycol and ethanol on Pt(111) and Ni/Pt(111) with surface d-band center.

    PubMed

    Skoplyak, Orest; Barteau, Mark A; Chen, Jingguang G

    2006-02-01

    The dehydrogenation and decarbonylation of ethylene glycol and ethanol were studied using temperature programmed desorption (TPD) on Pt(111) and Ni/Pt(111) bimetallic surfaces, as probe reactions for the reforming of oxygenates for the production of H2 for fuel cells. Ethylene glycol reacted via dehydrogenation to form CO and H2, corresponding to the desired reforming reaction, and via total decomposition to produce C(ad), O(ad), and H2. Ethanol reacted by three reaction pathways, dehydrogenation, decarbonylation, and total decomposition, producing CO, H2, CH4, C(ad), and O(ad). Surfaces prepared by deposition of a monolayer of Ni on Pt(111) at 300 K, designated Ni-Pt-Pt(111), displayed increased reforming activity compared to Pt(111), subsurface monolayer Pt-Ni-Pt(111), and thick Ni/Pt(111). Reforming activity was correlated with the d-band center of the surfaces and displayed a linear trend for both ethylene glycol and ethanol, with activity increasing as the surface d-band center moved closer to the Fermi level. This trend was opposite to that previously observed for hydrogenation reactions, where increased activity occurred on subsurface monolayers as the d-band center shifted away from the Fermi level. Extrapolation of the correlation between activity and the surface d-band center of bimetallic systems may provide useful predictions for the selection and rational design of bimetallic catalysts for the reforming of oxygenates. PMID:16471734

  11. Ethylene and pollination decrease transcript abundance of an ethylene receptor gene in Dendrobium petals.

    PubMed

    Thongkum, Monthathip; Burns, Parichart; Bhunchoth, Anjana; Warin, Nuchnard; Chatchawankanphanich, Orawan; van Doorn, Wouter G

    2015-03-15

    We studied the expression of a gene encoding an ethylene receptor, called Ethylene Response Sensor 1 (Den-ERS1), in the petals of Dendrobium orchid flowers. Transcripts accumulated during the young floral bud stage and declined by the time the flowers had been open for several days. Pollination or exposure to exogenous ethylene resulted in earlier flower senescence, an increase in ethylene production and a lower Den-ERS1 transcript abundance. Treatment with 1-methylcyclopropene (1-MCP), an inhibitor of the ethylene receptor, decreased ethylene production and resulted in high transcript abundance. The literature indicates two kinds of ethylene receptor genes with regard to the effects of ethylene. One group shows ethylene-induced down-regulated transcription, while the other has ethylene-induced up-regulation. The present gene is an example of the first group. The 5' flanking region showed binding sites for Myb and myb-like, homeodomain, MADS domain, NAC, TCP, bHLH and EIN3-like transcription factors. The binding site for the EIN3-like factor might explain the ethylene effect on transcription. A few other transcription factors (RAV1 and NAC) seem also related to ethylene effects. PMID:25590685

  12. Hemoglobin adducts from acrylonitrile and ethylene oxide in cigarette smokers: effects of glutathione S-transferase T1-null and M1-null genotypes.

    PubMed

    Fennell, T R; MacNeela, J P; Morris, R W; Watson, M; Thompson, C L; Bell, D A

    2000-07-01

    Acrylonitrile (ACN) is used to manufacture plastics and fibers. It is carcinogenic in rats and is found in cigarette smoke. Ethylene oxide (EO) is a metabolite of ethylene, also found in cigarette smoke, and is carcinogenic in rodents. Both ACN and EO undergo conjugation with glutathione. The objectives of this study were to examine the relationship between cigarette smoking and hemoglobin adducts derived from ACN and EO and to investigate whether null genotypes for glutathione transferase (GSTM1 and GSTT1) alter the internal dose of these agents. The hemoglobin adducts N-(2-cyanoethyl)valine (CEVal), which is formed from ACN, and N-(2-hydroxyethyl)valine (HEVal), which is formed from EO, and GST genotypes were determined in blood samples obtained from 16 nonsmokers and 32 smokers (one to two packs/day). Smoking information was obtained by questionnaire, and plasma cotinine levels were determined by immunoassay. Glutathione transferase null genotypes (GSTM1 and GSTT1) were determined by PCR. Both CEVal and HEVal levels increased with increased cigarette smoking dose (both self-reported and cotinine-based). CEVal and HEVal levels were also correlated. GSTM1 and GSTT1 genotypes had little effect on CEVal concentrations. GSTM1 null genotypes had no significant impact on HEVal. However, HEVal levels were significantly elevated in GSTT1-null individuals when normalized to smoking status or cotinine levels. The ratio of HEVal:CEVal was also elevated in GSTT1-null smokers (1.50 +/- 0.57 versus 0.88 +/- 0.24; P = 0.0002). The lack of a functional GSTT1 is estimated to increase the internal dose of EO derived from cigarette smoke by 50-70%. PMID:10919741

  13. The Phytohormone Ethylene Enhances Cellulose Production, Regulates CRP/FNRKx Transcription and Causes Differential Gene Expression within the Bacterial Cellulose Synthesis Operon of Komagataeibacter (Gluconacetobacter) xylinus ATCC 53582.

    PubMed

    Augimeri, Richard V; Strap, Janice L

    2015-01-01

    Komagataeibacter (formerly Gluconacetobacter) xylinus ATCC 53582 is a plant-associated model organism for bacterial cellulose (BC) biosynthesis. This bacterium inhabits the carposphere where it interacts with fruit through the bi-directional transfer of phytohormones. The majority of research regarding K. xylinus has been focused on identifying and characterizing structural and regulatory factors that control BC biosynthesis, but its ecophysiology has been generally overlooked. Ethylene is a phytohormone that regulates plant development in a variety of ways, but is most commonly known for its positive role on fruit ripening. In this study, we utilized ethephon (2-chloroethylphosphonic acid) to produce in situ ethylene to investigate the effects of this phytohormone on BC production and the expression of genes known to be involved in K. xylinus BC biosynthesis (bcsA, bcsB, bcsC, bcsD, cmcAx, ccpAx and bglAx). Using pellicle assays and reverse transcription quantitative polymerase chain reaction (RT-qPCR), we demonstrate that ethephon-derived ethylene enhances BC directly in K. xylinus by up-regulating the expression of bcsA and bcsB, and indirectly though the up-regulation of cmcAx, ccpAx, and bglAx. We confirm that IAA directly decreases BC biosynthesis by showing that IAA down-regulates bcsA expression. Similarly, we confirm that ABA indirectly influences BC biosynthesis by showing it does not affect the expression of bcs operon genes. In addition, we are the first to report the ethylene and indole-3-acetic acid (IAA) induced differential expression of genes within the bacterial cellulose synthesis (bcs) operon. Using bioinformatics we have identified a novel phytohormone-regulated CRP/FNRKx transcription factor and provide evidence that it influences BC biosynthesis in K. xylinus. Lastly, utilizing current and previous data, we propose a model for the phytohormone-mediated fruit-bacteria interactions that K. xylinus experiences in nature. PMID:26733991

  14. The Phytohormone Ethylene Enhances Cellulose Production, Regulates CRP/FNRKx Transcription and Causes Differential Gene Expression within the Bacterial Cellulose Synthesis Operon of Komagataeibacter (Gluconacetobacter) xylinus ATCC 53582

    PubMed Central

    Augimeri, Richard V.; Strap, Janice L.

    2015-01-01

    Komagataeibacter (formerly Gluconacetobacter) xylinus ATCC 53582 is a plant-associated model organism for bacterial cellulose (BC) biosynthesis. This bacterium inhabits the carposphere where it interacts with fruit through the bi-directional transfer of phytohormones. The majority of research regarding K. xylinus has been focused on identifying and characterizing structural and regulatory factors that control BC biosynthesis, but its ecophysiology has been generally overlooked. Ethylene is a phytohormone that regulates plant development in a variety of ways, but is most commonly known for its positive role on fruit ripening. In this study, we utilized ethephon (2-chloroethylphosphonic acid) to produce in situ ethylene to investigate the effects of this phytohormone on BC production and the expression of genes known to be involved in K. xylinus BC biosynthesis (bcsA, bcsB, bcsC, bcsD, cmcAx, ccpAx and bglAx). Using pellicle assays and reverse transcription quantitative polymerase chain reaction (RT-qPCR), we demonstrate that ethephon-derived ethylene enhances BC directly in K. xylinus by up-regulating the expression of bcsA and bcsB, and indirectly though the up-regulation of cmcAx, ccpAx, and bglAx. We confirm that IAA directly decreases BC biosynthesis by showing that IAA down-regulates bcsA expression. Similarly, we confirm that ABA indirectly influences BC biosynthesis by showing it does not affect the expression of bcs operon genes. In addition, we are the first to report the ethylene and indole-3-acetic acid (IAA) induced differential expression of genes within the bacterial cellulose synthesis (bcs) operon. Using bioinformatics we have identified a novel phytohormone-regulated CRP/FNRKx transcription factor and provide evidence that it influences BC biosynthesis in K. xylinus. Lastly, utilizing current and previous data, we propose a model for the phytohormone-mediated fruit-bacteria interactions that K. xylinus experiences in nature. PMID:26733991

  15. Effect of SiO2-acryl nanohybrid coating layers on transparent conducting oxide-poly(ethylene terephthalate) superstrate.

    PubMed

    Kang, Y T; Kang, D P; Kang, D J; Chung, I D

    2013-05-01

    SiO2-acryl nanohybrid coating layers were produced by hybridizing acrylic resin and surface-modified colloidal silica (CS) nanoparticles. First, CS nanoparticles were modified with methyltrimethoxysilane (MTMS) and vinyltrimethoxysilane (VTMS) by a sol-gel process. The surface-modified CS nanoparticles were then solvent-exchanged to be homogeneous in acrylic resin. The Hybrid materials were mixed in variation with the amount of surface-modified CS nanoparticles, coated with poly(ethylene terephthalate) (PET), then finally cured by UV light to obtain a hybrid coating layer. Field emission scanning electron microscopy (FE-SEM), particle size analysis (using a Zetasizer), and atomic force microscopy (AFM) were performed to determine the morphology of the hybrid thin-films. Thermogravimetric analysis (TGA) was used to investigate the thermal properties. Fourier-transform infrared (FTIR), ultraviolet-visible (UVNis) spectroscopies, and pencil hardness were used to obtain the details of chemical structures, optical properties, and hardness, respectively. The hybrid thin films had shown to be enhanced properties compared to their urethane acrylate prepolymer (UAP) coating film. PMID:23858925

  16. Model isomorphism in oxidized-bitumen production

    SciTech Connect

    Grudnikov, I.B.

    1988-11-10

    Phenomena differing in nature may have mathematical descriptions identical in form; examples are the similarities between the expressions for Fick's first law and Fourier's law, which describe mass and energy transfer correspondingly. One can thus use model isomorphism in simulation, which can accelerate the process, since it is merely necessary to check that the model fit is adequate. The author has compared two forms of simulation: from model isomorphism and from studies on kinetics and dynamics in application to oxidized-bitumen production, as the material is important, and increased output has a bearing on improving oil refining. This model is adequate and can be derived from the isomorphism principle as well as from the kinetics and dynamics. The principle does not replace research on the process but enables one to derive models more rapidly for processing petroleum fractions characterized by complicated compositions and reactions.

  17. Evaluation of ethylene as a mediator of gravitropism by tomato hypocotyls

    NASA Technical Reports Server (NTRS)

    Harrison, M. A.; Pickard, B. G.

    1986-01-01

    Assessments of the participation of ethylene in gravitropism by hypocotyls of tomato (Lycopersicon esculentum Mill.) indicate that gravitropism can occur without substantial change in ethylene production. Moreover, lowering or evaluating ethylene over a considerable range, as well as inhibiting ethylene action, fails to influence gravitropic bending. This vitiates the possibility that ethylene is a mediator of the primary, negative gravitropic response of tomato shoots.

  18. Ethylene Gas in Storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ethylene is a small volatile organic molecule that is produced by plants and many microbes. Potato tubers sense ethylene at concentrations of less than 1 ppm and respond to ethylene in ways that may be beneficial or detrimental for potato tuber storage. High concentrations of ethylene suppress sprou...

  19. The efficacy of antioxidant therapy against oxidative stress and androgen rise in ethylene glycol induced nephrolithiasis in Wistar rats.

    PubMed

    Naghii, M R; Jafari, M; Mofid, M; Eskandari, E; Hedayati, M; Khalagie, K

    2015-07-01

    Administration of natural antioxidants has been used to protect against nephrolithiasis. Urolithiasis was induced by ethylene glycol (EG) in Wistar rats. For 4 weeks, group 1 (control) was fed with a standard commercial diet. Group 2 received the same diet with 0.75% of EG. Group 3 received EG plus the diet and water added with antioxidant nutrients and lime juice as the dietary source of citrate (EG + AX). Group 4 same as group 3 with no EG in water. For 8 weeks, group 5 was fed the standard diet with EG in water for the first 28 days, followed by no EG. Group 6 received the diet with EG for the first 28 days, followed by discontinuation of EG and addition of antioxidant nutrients. Group 7 were provided the diet with antioxidant nutrients for 8 weeks. Group 8 received the diet with antioxidant nutrients for 4 weeks, followed by antioxidant nutrients with EG for the next 4 weeks. Blood samples were collected and kidneys were removed. The size and the mean number of crystal deposits in EG-treated groups was significantly higher than the EG-treated groups, added with antioxidant nutrients and lime juice. After 4 weeks, the mean concentration of malondialdehyde in group 2 was higher than the group 3, and significantly lower in group 4; and in groups 7 after 8 weeks, as well. After 8 weeks, supplementation developed less mean number of deposits in group 6 as compared to group 5; and in group 8, the crystal deposits was substantially less than either group 2 or group 5 (EG-treated rats). Elevated concentration of androgens (as promoters of the formation of renal calculi) as a result of EG consumption decreased following antioxidant supplementations. Results showed a beneficial effect of antioxidant and provided superior renal protection on treating and preventing stone deposition in the rat kidney. PMID:25392345

  20. 40 CFR Table 4 to Subpart Ppp of... - Known Organic HAP From Polyether Polyol Products

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Polyol Products Organic HAP/chemical name 1,3 Butadiene (106990) Epichlorohydrin (106898) Ethylene Oxide (75218) n-Hexane (110543) Methanol (67561) Propylene Oxide (75569) Toluene (108883) CAS No. = Chemical Abstracts Service Registry Number....

  1. 40 CFR Table 4 to Subpart Ppp of... - Known Organic HAP From Polyether Polyol Products

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Products Organic HAP/chemical name 1,3 Butadiene (106990) Epichlorohydrin (106898) Ethylene Oxide (75218) n-Hexane (110543) Methanol (67561) Propylene Oxide (75569) Toluene (108883) CAS No. = Chemical...

  2. Viscoelastic Properties, Ionic Conductivity, and Materials Design Considerations for Poly(styrene-b-ethylene oxide-b-styrene)-Based Ion Gel Electrolytes

    SciTech Connect

    Zhang, Sipei; Lee, Keun Hyung; Sun, Jingru; Frisbie, C. Daniel; Lodge, Timothy P.

    2013-03-07

    The viscoelastic properties and ionic conductivity of ion gels based on the self-assembly of a poly(styrene-b-ethylene oxide-b-styrene) (SOS) triblock copolymer (M{sub n,S} = 3 kDa, M{sub n,O} = 35 kDa) in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([EMI][TFSA]) were investigated over the composition range of 10-50 wt % SOS and the temperature range of 25-160 C. The poly(styrene) (PS) end-blocks associate into micelles, whereas the poly(ethylene oxide) (PEO) midblocks are well-solvated by this ionic liquid. The ion gel with 10 wt % SOS melts at 54 C, with the longest relaxation time exhibiting a similar temperature dependence to that of the viscosity of bulk PS. However, the actual values of the gel relaxation time are more than 4 orders of magnitude larger than the relaxation time of bulk PS. This is attributed to the thermodynamic penalty of pulling PS end-blocks through the PEO/[EMI][TFSA] matrix. Ion gels with 20-50 wt % SOS do not melt and show two plateaus in the storage modulus over the temperature and frequency ranges measured. The one at higher frequencies is that of an entangled network of PEO strands with PS cross-links; the modulus displays a quadratic dependence on polymer weight fraction and agrees with the prediction of linear viscoelastic theory assuming half of the PEO chains are elastically effective. The frequency that separates the two plateaus, {omega}{sub c}, reflects the time scale of PS end-block pull-out. The other plateau at lower frequencies is that of a congested micelle solution with PS cores and PEO coronas, which has a power law dependence on domain spacing similar to diblock melts. The ionic conductivity of the ion gels is compared to PEO homopolymer solutions at similar polymer concentrations; the conductivity is reduced by a factor of 2.1 or less, decreases with increasing PS volume fraction, and follows predictions based on a simple obstruction model. Our collective results allow the formulation

  3. The impact of cold storage and ethylene on volatile ester production and aroma perception in 'Hort16A' kiwifruit.

    PubMed

    Günther, Catrin S; Marsh, Ken B; Winz, Robert A; Harker, Roger F; Wohlers, Mark W; White, Anne; Goddard, Matthew R

    2015-02-15

    Fruit esters are regarded as key volatiles for fruit aroma. In this study, the effects of cold storage on volatile ester levels of 'Hort16A' (Actinidia chinensis Planch. var chinensis) kiwifruit were examined and the changes in aroma perception investigated. Cold storage (1.5°C) for two or four months of fruit matched for firmness and soluble solids concentration resulted in a significant reduction in aroma-related esters such as methyl/ethyl propanoate, methyl/ethyl butanoate and methyl/ethyl hexanoate. Levels of these esters, however, were restored by ethylene treatment (100ppm, 24h) before ripening. A sensory panel found that "tropical" and "fruit candy" aroma was stronger and "green" odour notes less intensively perceived in kiwifruit which were ethylene-treated after cold storage compared to untreated fruit. The key findings presented in this study may lead to further work on the ethylene pathway, and innovative storage and marketing solutions for current and novel fruit cultivars. PMID:25236191

  4. Effect of 1-Butyl-3-methylimidazolium Halide on the Relative Stability between Sodium Dodecyl Sulfate Micelles and Sodium Dodecyl Sulfate-Poly(ethylene oxide) Nanoaggregates.

    PubMed

    Ferreira, Gabriel M Dias; Ferreira, Guilherme M Dias; Agudelo, Álvaro J Patiño; Hespanhol da Silva, Maria C; Rezende, Jaqueline de Paula; Pires, Ana Clarissa Dos Santos; da Silva, Luis Henrique Mendes

    2015-12-24

    It is well-known that ionic liquids (ILs) alter the properties of aqueous systems containing only surfactants. However, the effect of ILs on polymer-surfactant systems is still unknown. Here, the effect of 1-butyl-3-methylimidazolium bromide (bmimBr) and chloride (bmimCl) on the micellization of sodium dodecyl sulfate (SDS) and its interaction with poly(ethylene oxide) (PEO) was evaluated using conductimetry, fluorimetry, and isothermal titration calorimetry. The ILs decreased the critical micellar concentration (cmc) of the surfactant, stabilizing the SDS micelles. A second critical concentration (c2thc) was verified at high SDS concentrations, due to the micelle size decrease. The stability of PEO/SDS aggregates was also affected by ILs, and the critical aggregation concentration (cac) of SDS increased. Integral aggregation enthalpy changed from -0.72 in water to 2.16 kJ mol(-1) in 4.00 mM bmimBr. IL anions did not affect the SDS micellization or the beginning of PEO/SDS aggregation. Nevertheless, when chloride was replaced with bromide, the amount of SDS bound to the polymer increased. At 100.0 mM IL, the PEO-SDS interaction vanished. We suggest that the effect of ILs comes from participating in the structure of the formed aggregates, interacting with the SDS monomers at the core/interface of the micelles, and promoting preferential solvation of the polymer. PMID:26595360

  5. Structural tailoring of hydrogen-bonded poly(acrylic acid)/poly(ethylene oxide) multilayer thin films for reduced gas permeability.

    PubMed

    Xiang, Fangming; Ward, Sarah M; Givens, Tara M; Grunlan, Jaime C

    2015-02-01

    Hydrogen bonded poly(acrylic acid) (PAA)/poly(ethylene oxide) (PEO) layer-by-layer assemblies are highly elastomeric, but more permeable than ionically bonded thin films. In order to expand the use of hydrogen-bonded assemblies to applications that require a better gas barrier, the effect of assembling pH on the oxygen permeability of PAA/PEO multilayer thin films was investigated. Altering the assembling pH leads to significant changes in phase morphology and bonding. The amount of intermolecular hydrogen bonding between PAA and PEO is found to increase with increasing pH due to reduction of COOH dimers between PAA chains. This improved bonding leads to smaller PEO domains and lower gas permeability. Further increasing the pH beyond 2.75 results in higher oxygen permeability due to partial deprotonation of PAA. By setting the assembling pH at 2.75, the negative impacts of COOH dimer formation and PAA ionization on intermolecular hydrogen bonding can be minimized, leading to a 50% reduction in the oxygen permeability of the PAA/PEO thin film. A 20 bilayer coating reduces the oxygen transmission rate of a 1.58 mm natural rubber substrate by 20 ×. These unique nanocoatings provide the opportunity to impart a gas barrier to elastomeric substrates without altering their mechanical behavior. PMID:25519816

  6. On-line sample preconcentration by sweeping and poly(ethylene oxide)-mediated stacking for simultaneous analysis of nine pairs of amino acid enantiomers in capillary electrophoresis.

    PubMed

    Lin, En-Ping; Lin, Kai-Cheng; Chang, Chia-Wei; Hsieh, Ming-Mu

    2013-09-30

    This study proposes a sensitive method for the simultaneous separation and concentration of 9 pairs of amino acid enantiomers by combining poly(ethylene oxide) (PEO)-based stacking, β-cyclodextrin (β-CD)-mediated micellar electrokinetic chromatography (MEKC), and 9-fluoroenylmethyl chloroformate (FMOC) derivatization. The 9 pairs of FMOC-derivatized amino acid enantiomers were baseline separated using a discontinuous system, and the buffer vials contained a solution of 150 mM Tris-borate (TB), 12.5% (v/v) isopropanol (IPA), 0.5% (w/v) PEO, 35 mM sodium taurodeoxycholate (STDC), and 35 mM β-CD, and the capillary was filled with a solution of 1.5 M TB, 12.5% (v/v) IPA, 35 mM STDC, and 35 mM β-CD. Based on the difference in viscosity between the sample zone and PEO solution and because of the STDC sweeping, the discontinuous system effectively stacked 670 nL of the 9 pairs of FMOC-derivatized amino acid enantiomers without losing chiral resolution. Consequently, the limits of detection for the 9 pairs of FMOC-derivatized amino acid enantiomers were reduced to 40-60 nM. This method was successfully used to determine d-Tryptophan (Trp), l-Trp, d-Phenylalanine (Phe), l-Phe, d-Glutamic acid (Glu), and l-Glu in various types of beers. PMID:23953474

  7. Polyelectrolyte-surfactant complexes formed by poly[3,5-bis(trimethylammoniummethyl)4-hydroxystyrene iodide]-block-poly(ethylene oxide) and sodium dodecyl sulfate in aqueous solutions.

    PubMed

    Štěpánek, Miroslav; Matějíček, Pavel; Procházka, Karel; Filippov, Sergey K; Angelov, Borislav; Šlouf, Miroslav; Mountrichas, Grigoris; Pispas, Stergios

    2011-05-01

    Formation of polyelectrolyte-surfactant (PE-S) complexes of poly[3,5-bis(trimethylammoniummethyl)-4-hydroxystyrene iodide]-block-poly(ethylene oxide) (QNPHOS-PEO) and sodium dodecyl sulfate (SDS) in aqueous solution was studied by dynamic and electrophoretic light scattering, small-angle X-ray scattering (SAXS), atomic force microscopy, and fluorometry, using pyrene as a fluorescent probe. SAXS data from the QNPHOS-PEO/SDS solutions were fitted assuming contributions from free copolymer, PE-S aggregates described by a mass fractal model, and densely packed surfactant micelles inside the aggregates. It was found that, unlike other systems of a double hydrophilic block polyelectrolyte and an oppositely charged surfactant, PE-S aggregates of the QNPHOS-PEO/SDS system do not form core-shell particles and the PE-S complex precipitates before reaching the charge equivalence between dodecyl sulfate anions and QNPHOS polycationic blocks, most likely because of conformational rigidity of the QNPHOS blocks, which prevents the system from the corresponding rearrangement. PMID:21446735

  8. Preparation of magnetic core-shell iron oxide@silica@nickel-ethylene glycol microspheres for highly efficient sorption of uranium(VI).

    PubMed

    Tan, Lichao; Zhang, Xiaofei; Liu, Qi; Wang, Jun; Sun, Yanbo; Jing, Xiaoyan; Liu, Jingyuan; Song, Dalei; Liu, Lianhe

    2015-04-21

    We report a facile approach for the formation of magnetic core-shell iron oxide@silica@nickel-ethylene glycol (Fe3O4@SiO2@Ni-L) microspheres. The structure and morphology of Fe3O4@SiO2@Ni-L are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen sorption isotherm. The composite possesses a high specific surface area of 382 m(2) g(-1). The obtained core/shell structure is composed of a superparamagnetic core with a strong response to external fields, which are recovered readily from aqueous solutions by magnetic separation. When used as the adsorbent for uranium(vi) in water, the as-prepared Fe3O4@SiO2@Ni-L multi-structural microspheres exhibit a high adsorption capacity, which is mainly attributed to the large specific surface area and typical mesoporous characteristics of Fe3O4@SiO2@Ni-L microspheres. This work provides a promising approach for the design and synthesis of multifunctional microspheres, which can be used for water treatment, as well as having other potential applications in a variety of biomedical fields including drug delivery and biosensors. PMID:25773512

  9. Conformational and Dynamic Properties of Poly(ethylene oxide) in an Ionic Liquid: Development and Implementation of a First-Principles Force Field.

    PubMed

    McDaniel, Jesse G; Choi, Eunsong; Son, Chang-Yun; Schmidt, J R; Yethiraj, Arun

    2016-01-14

    The conformational properties of polymers in ionic liquids are of fundamental interest but not well understood. Atomistic and coarse-grained molecular models predict qualitatively different results for the scaling of chain size with molecular weight, and experiments on dilute solutions are not available. In this work, we develop a first-principles force field for poly(ethylene oxide) (PEO) in the ionic liquid 1-butyl 3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) using symmetry adapted perturbation theory (SAPT). At temperatures above 400 K, simulations employing both the SAPT and OPLS-AA force fields predict that PEO displays ideal chain behavior, in contrast to previous simulations at lower temperature. We therefore argue that the system shows a transition from extended to more compact configurations as the temperature is increased from room temperature to the experimental lower critical solution temperature. Although polarization is shown to be important, its implicit inclusion in the OPLS-AA force is sufficient to describe the structure and energetics of the mixture. The simulations emphasize the difference between ionic liquids from typical solvents for polymers. PMID:26690901

  10. Biological and Tribological Assessment of Poly(Ethylene Oxide Terephthalate)/Poly(Butylene Terephthalate), Polycaprolactone, and Poly (L\\DL) Lactic Acid Plotted Scaffolds for Skeletal Tissue Regeneration.

    PubMed

    Hendrikson, Wilhelmus J; Zeng, Xiangqiong; Rouwkema, Jeroen; van Blitterswijk, Clemens A; van der Heide, Emile; Moroni, Lorenzo

    2016-01-21

    Additive manufactured scaffolds are fabricated from three commonly used biomaterials, polycaprolactone (PCL), poly (L\\DL) lactic acid (P(L\\DL)LA), and poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT). Scaffolds are compared biologically and tribologically. Cell-seeded PEOT/PBT scaffolds cultured in osteogenic and chondrogenic differentiation media show statistical significantly higher alkaline phosphatase (ALP) activity/DNA and glycosaminoglycans (GAG)/DNA ratios, followed by PCL and P(L\\DL)LA scaffolds, respectively. The tribological performance is assessed by determining the friction coefficients of the scaffolds at different loads and sliding velocities. With increasing load or decreasing sliding velocity, the friction coefficient value decreases. PEOT/PBT show to have the lowest friction coefficient value, followed by PCL and P(L\\DL)LA. The influence of the scaffold architecture is further determined with PEOT/PBT. Reducing of the fiber spacing results in a lower friction coefficient value. The best and the worst performing scaffold architecture are chosen to investigate the effect of cell culture on the friction coefficient. Matrix deposition is low in the cell-seeded scaffolds and the effect is, therefore, undetermined. Taken together, our studies show that PEOT/PBT scaffolds support better skeletal differentiation of seeded stromal cells and lower friction coefficient compared to PCL and P(L/DL)A scaffolds. PMID:26775915

  11. The preparation and characterization of highly aligned poly(epsilon-caprolactone)/poly ethylene oxide/chitosan ultrafine fiber for the application to tissue scaffold.

    PubMed

    Nien, Yu-Hsun; Wang, Jia-Yi; Tsai, Yan-Sheng

    2013-07-01

    The purpose of this study was to fabricate poly(epsilon-caprolactone) (PCL)/poly ethylene oxid (PEO)/chitosan (CS) ultrafine fiber in both aligned and random structures using electrospinning technique and their process parameters were optimized. The aligned and random PCL/PEO/chitosan ultrafine fibers were also used as scaffold for tissue engineering and their cell affinity was investigated. In the first part, we inspected the effect of environment conditions, solution properties, process parameters on PCL/PEO/chitosan ultrafine fiber. In the second part, the apparatus of electrospinning to manufacture highly aligned PCL/PEO/chitosan ultrafine fiber was developed. The effects of process parameters such as flow rate, design of collector and rotation speed of collecting drum on the morphology of ultrafine fiber were discussed. In addition, the cross link of PCL/PEO/chitosan ultrafine fiber by cross-linking agent was examined, too. The physical properties, chemical properties, and cell affinities of the aligned PCL/PEO/chitosan ultrafine fiber with or without cross link were measured. The chemical analysis and tensile strength of the ultrafine fiber were characterized using Fourier Transfer Infared Spectrophotometer and Universal Tensile Machine, respectively. The results show that the aligned PCL/PEO/chitosan ultrafine fibrous mat had the capacity to induce cellular alignment and enhance cellular elongation. PMID:23901493

  12. Organic-inorganic random copolymers from methacrylate-terminated poly(ethylene oxide) with 3-methacryloxypropylheptaphenyl polyhedral oligomeric silsesquioxane: synthesis via RAFT polymerization and self-assembly behavior.

    PubMed

    Wei, Kun; Li, Lei; Zheng, Sixun; Wang, Ge; Liang, Qi

    2014-01-14

    In this contribution, we report the synthesis of organic-inorganic random polymers from methacrylate-terminated poly(ethylene oxide) (MAPEO) (Mn = 950) and 3-methacryloxypropylheptaphenyl polyhedral oligomeric silsesquioxane (MAPOSS) macromers via reversible addition-fragmentation chain transfer (RAFT) polymerization with 4-cyano-4-(thiobenzoylthio) valeric acid (CTBTVA) as the chain transfer agent. The organic-inorganic random copolymers were characterized by means of (1)H NMR spectroscopy, gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). The results of GPC indicate that the polymerizations were carried out in a controlled fashion. Transmission electron microscopy (TEM) showed that the organic-inorganic random copolymers in bulk were microphase-separated and the POSS microdomains were formed via POSS-POSS interactions. In aqueous solutions the organic-inorganic random copolymers were capable of self-assembling into spherical nanoobjects as evidenced by transmission electron microscopy (TEM) and dynamic laser scattering (DLS). The self-assembly behavior of the organic-inorganic random copolymers was also found to occur in the mixtures with the precursors of epoxy. The nanostructures were further fixed via subsequent curing reaction and thus the organic-inorganic nanocomposites were obtained. The formation of nanophases in epoxy thermosets was confirmed by transmission electron microscopy (TEM) and dynamic mechanical thermal analysis (DMTA). The organic-inorganic nanocomposites displayed the enhanced surface hydrophobicity as evidenced by surface contact angle measurements. PMID:24651714

  13. Quantitative control of poly(ethylene oxide) surface antifouling and biodetection through azimuthally enhanced grating coupled-surface plasmon resonance sensing

    NASA Astrophysics Data System (ADS)

    Sonato, Agnese; Silvestri, Davide; Ruffato, Gianluca; Zacco, Gabriele; Romanato, Filippo; Morpurgo, Margherita

    2013-12-01

    Grating Coupled-Surface Plasmon reflectivity measurements carried out under azimuth and polarization control (GC-SPR φ ≠ 0°) were used to optimize the process of gold surface dressing with poly(ethylene oxide) (PEO) derivatives of different molecular weight, with the final goal to maximize the discrimination between specific and non-specific binding events occurring at the surface. The kinetics of surface deposition of thiol-ending PEOs (0.3, 2 and 5 kDa), introduced as antifouling layers, was monitored. Non-specific binding events upon immersion of the surfaces into buffers containing either 0.1% bovine serum albumin or 1% Goat Serum, were evaluated as a function of polymer size and density. A biorecognition event between avidin and biotin was then monitored in both buffers at selected low and high polymer surface densities and the contribution of analyte and fouling elements to the signal was precisely quantified. The 0.3 kDa PEO film was unable to protect the surface from non-specific interactions at any tested density. On the other hand, the 2 and 5 kDa polymers at their highest surface densities guaranteed full protection from non-specific interactions from both buffers. These densities were reached upon a long deposition time (24-30 h). The results pave the way toward the application of this platform for the detection of low concentration and small dimension analytes, for which both non-fouling and high instrumental sensitivity are fundamental requirements.

  14. Core–Shell Structure of Monodisperse Poly(ethylene glycol)-Grafted Iron Oxide Nanoparticles Studied by Small-Angle X-ray Scattering

    PubMed Central

    2015-01-01

    The promising applications of core–shell nanoparticles in the biological and medical field have been well investigated in recent years. One remaining challenge is the characterization of the structure of the hydrated polymer shell. Here we use small-angle X-ray scattering (SAXS) to investigate iron oxide core–poly(ethylene glycol) brush shell nanoparticles with extremely high polymer grafting density. It is shown that the shell density profile can be described by a scaling model that takes into account the locally very high grafting density near the core. A good fit to a constant density region followed by a star-polymer-like, monotonously decaying density profile is shown, which could help explain the unique colloidal properties of such densely grafted core–shell nanoparticles. SAXS experiments probing the thermally induced dehydration of the shell and the response to dilution confirmed that the observed features are associated with the brush and not attributed to structure factors from particle aggregates. We thereby demonstrate that the structure of monodisperse core–shell nanoparticles with dense solvated shells can be well studied with SAXS and that different density models can be distinguished from each other. PMID:26321792

  15. Nanoporous nonwoven fibril-like morphology by cooperative self-assembly of poly(ethylene oxide)-block-poly(ethyl acrylate)-block-polystyrene and phenolic resin.

    PubMed

    Deng, Guodong; Qiang, Zhe; Lecorchick, Willis; Cavicchi, Kevin A; Vogt, Bryan D

    2014-03-11

    Cooperative self-assembly of block copolymers with (in)organic precursors effectively generates ordered nanoporous films, but the porosity is typically limited by the need for a continuous (in)organic phase. Here, a network of homogeneous fibrous nanostructures (≈20 nm diameter cylinders) having high porosity (≈ 60%) is fabricated by cooperative self-assembly of a phenolic resin oligomer (resol) with a novel, nonfrustrated, ABC amphiphilic triblock copolymer template, poly(ethylene oxide)-block-poly(ethyl acrylate)-block-polystyrene (PEO-b-PEA-b-PS), via a thermally induced self-assembly process. Due to the high glass transition temperature (Tg) of the PS segments, the self-assembly behavior is kinetically hindered as a result of competing effects associated with the ordering of the self-assembled system and the cross-linking of resol that suppresses segmental mobility. The balance in these competing processes reproducibly yields a disordered fibril network with a uniform fibril diameter. This nonequilibrium morphology is dependent on the PEO-b-PEA-b-PS to resol ratio with an evolution from a relatively open fibrous structure to an apparent poorly ordered mixed lamellae-cylinder morphology. Pyrolysis of these former films at elevated temperatures yields a highly porous carbon film with the fibril morphology preserved through the carbonization process. These results illustrate a simple method to fabricate thin films and coatings with a well-defined fiber network that could be promising materials for energy and separation applications. PMID:24548298

  16. A Mode-Locked Soliton Erbium-Doped Fiber Laser with a Single-Walled Carbon Nanotube Poly-Ethylene Oxide Film Saturable Absorber

    NASA Astrophysics Data System (ADS)

    Z. R. R. Rosdin, R.; F., Ahmad; M. Ali, N.; M. Nor, R.; R. Zulkepely, N.; W. Harun, S.; Arof, H.

    2014-09-01

    We present a simple, compact and low-cost mode-locked erbium-doped fiber laser (EDFL) using single-walled carbon nanotubes (SWCNTs) embedded in a poly-ethylene oxide (PEO) thin film as a passive saturable absorber. The film is fabricated by using a prepared homogeneous SWCNT solution, which is mixed with a diluted PEO solution and cast onto a glass Petri dish to form, by evaporation, a thin film. The 50 μm-thick film is sandwiched between two fiber connectors to construct a saturable absorber, which is then integrated in an EDFL cavity to generate self-started stable soliton pulses operating at 1560.8 nm. The soliton pulse starts to lase at a pump power threshold of 12.3 mW with a repetition rate of 11.21 MHz, a pulse width of 1.02 ps, an average output power of 0.65 mW and a pulse energy of 57.98 pJ.

  17. Stability of Water/Poly(ethylene oxide)43-b-poly(ε-caprolactone)14/Cyclohexanone Emulsions Involves Water Exchange between the Core and the Bulk.

    PubMed

    Flores, Mario E; Martínez, Francisco; Olea, Andrés F; Shibue, Toshimichi; Sugimura, Natsuhiko; Nishide, Hiroyuki; Moreno-Villoslada, Ignacio

    2015-12-31

    The formation of emulsions upon reverse self-association of the monodisperse amphiphilic block copolymer poly(ethylene oxide)43-b-poly(ε-caprolactone)14 in cyclohexanone is reported. Such emulsions are not formed in toluene, chloroform, or dichloromethane. We demonstrate by magnetic resonance spectroscopy the active role of the solvent on the stabilization of the emulsions. Cyclohexanone shows high affinity for both blocks, as predicted by the Hansen solubility parameters, so that the copolymer chains are fully dissolved as monomeric chains. In addition, the solvent is able to produce hydrogen bonding with water molecules. Water undergoes molecular exchange between water molecules associated with the polymer and water molecules associated with the solvent, dynamics of major importance for the stabilization of the emulsions. Association of polymeric chains forming reverse aggregates is induced by water over a concentration threshold of 5 wt %. Reverse copolymer aggregates show submicron average hydrodynamic diameters, as seen by dynamic light scattering, depending on the polymer and water concentration. PMID:26637018

  18. Synthesis and characterizations of palladium catalysts with high activity and stability for formic acid oxidation by hydrogen reduction in ethylene glycol at room temperature

    NASA Astrophysics Data System (ADS)

    Wu, Meixia; Li, Muwu; Wu, Xin; Li, Yuexia; Zeng, Jianhuang; Liao, Shijun

    2015-10-01

    In this work, a Pd/C catalyst with high activity as well as excellent stability has been prepared by hydrogen gas reduction of Pd(II) precursor in ethylene glycol solution with the assistance of appropriate amount of sodium citrate. Pd nanoparticles with an average particle size of 3.8 nm and excellent uniformity are obtained. The Pd/C catalyst synthesized in this work shows an electrochemical surface area of 68.6 m2 g-1 and displays activities of 819 A g-1. Strikingly, the Pd/C catalyst also exhibits excellent stability, which has been confirmed by its slow activity decay under repeated potential cycles as well as chronoamperometric test. The activity for Pd/C at the 300th and 500th cycle remains at 5.5 and 2.4 mA cm-2, respectively, which is 25% and 11% of its initial value, respectively. The oxidation currents at the Pd/C and Pd/C-Citrate (control) at 0 V decrease to 44% and 25% of their initial values. Transmission electron microscopy observations on the Pd/C catalyst after 1000 potential cycles reveal that, in addition to carbon support corrosion, Pd agglomeration together with more serious Pd dissolution occur at the same time, leading to a decrease of the electrocatalytic performance.

  19. Reversible de-intercalation and intercalation induced by polymer crystallization and melting in a poly(ethylene oxide)/organoclay nanocomposite.

    PubMed

    Sun, Lu; Ertel, Ethan A; Zhu, Lei; Hsiao, Benjamin S; Avila-Orta, Carlos A; Sics, Igors

    2005-06-21

    Semicrystalline polymer/layered silicate nanocomposites were prepared by solution blending of a low molecular weight poly(ethylene oxide) (PEO) with an organically modified montmorillonite, Cloisite 10A (C10A). The intercalation morphology was studied by temperature-dependent synchrotron wide-angle X-ray diffraction (WAXD). Unlike PEO homopolymers, significant secondary crystallization was observed in the PEO/C10A nanocomposites. Reversible de-intercalation and intercalation processes were detected during secondary crystallization and subsequent melting of secondary crystals. On the basis of two-dimensional WAXD results on oriented samples, an interphase layer between the silicate primary particles and PEO lamellar crystals was proposed. Secondary PEO crystallization in the interphase regions was inferred to be the primary driving force for polymer chains to diffuse out of the silicate gallery. This study provided a useful method to investigate polymer diffusion in nanoconfined spaces, which can be controlled by PEO secondary crystallization and melting outside the silicate gallery. PMID:15952806

  20. Mesoscale simulation of the formation and dynamics of lipid-structured poly(ethylene oxide)-block-poly(methyl methacrylate) diblock copolymers.

    PubMed

    Mu, Dan; Li, Jian-Quan; Feng, Sheng-Yu

    2015-05-21

    Twelve poly(ethylene oxide)-block-poly(methyl methacrylate) (PEO-b-PMMA) copolymers with lipid-like structures were designed and investigated by MesoDyn simulation. Spherical and worm-like micelles as well as bicontinuous, lamellar and defected lamellar phases were obtained. A special structure, designated B2412, with two lipid structures connected by their heads, was found to undergo four stages prior to forming a spherical micelle phase. Two possible assembly mechanisms were found via thermodynamic and dynamic process analyses; namely, the fusion and fission of micelles in dynamic equilibrium during the adjustment stage. Water can be encapsulated into these micelles, which can affect their size, particularly in low concentration aqueous solutions. The assignment of weak negative charges to the hydrophilic EO blocks resulted in a clear effect on micelle size. Surprisingly, the largest effect was observed with EO blocks with -0.5 e, wherein an ordered perfect hexagonal phase was formed. The obtained results can be applied in numerous fields of study, including adsorption, catalysis, controlled release and drug delivery. PMID:25898853

  1. Change in the Affinity of Ethylene Glycol Methacrylate Phosphate Monomer and Its Polymer Anchored on a Graphene Oxide Platform toward Uranium(VI) and Plutonium(IV) Ions.

    PubMed

    Chappa, Sankararao; Singha Deb, Ashish K; Ali, Sk Musharaf; Debnath, A K; Aswal, D K; Pandey, Ashok K

    2016-03-24

    The complexation behavior of the carbonyl and phosphoryl ligating groups bearing ethylene glycol methacrylate phosphate (EGMP) monomer and its polymer fixed on a graphene oxide (GO) platform was studied to understand the coordination ability of segregated EGMP units and polymer chains toward UO2(2+) and Pu(4+) ions. The cross-linked poly(EGMP) gel and EGMP dissolved in solution have a similar affinity toward these ions. UV-initiator induced polymerization was used to graft poly(EGMP) on the GO platform utilizing a double bond of EGMP covalently fixed on it. X-ray photoelectron spectroscopy (XPS) of the GO and GO-EGMP was done to confirm covalent attachment of the EGMP via a -C-O-P- link between GO and EGMP. The extent of poly(EGMP) grafting on GO by thermal analyses was found to be 5.88 wt %. The EGMP units fixed on the graphene oxide platform exhibited a remarkable selectivity toward Pu(4+) ions at high HNO3 conc. where coordination is a dominant mode involved in the sorption of ions. The ratio of distribution coefficients of Pu(IV) to U(VI) (DPu(IV)/DU(VI)) followed a trend as cross-linked poly(EGMP) (0.95) < EGMP in solvent methyl isobutyl ketone (1.3) < GO-poly(EGMP) (25) < GO-EGMP (181); the DPu(IV)/DU(VI) values are given in parentheses. The density functional theory computations have been performed for the complexation of UO2(2+) and Pu(4+) ions with the EGMP molecule anchored on GO in the presence of nitrate ions. This computational modeling suggested that Pu(4+) ion formed a strong coordination complex with phosphoryl and carbonyl ligating groups of the GO-EGMP as compared to UO2(2+) ions. Thus, the nonselective EGMP becomes highly selective to Pu(IV) ions when it interacts as a single unit fixed on a GO platform. PMID:26926256

  2. 21 CFR 573.440 - Ethylene dichloride.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Ethylene dichloride. 573.440 Section 573.440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.440 Ethylene...

  3. Ethylene and Metal Stress: Small Molecule, Big Impact.

    PubMed

    Keunen, Els; Schellingen, Kerim; Vangronsveld, Jaco; Cuypers, Ann

    2016-01-01

    The phytohormone ethylene is known to mediate a diverse array of signaling processes during abiotic stress in plants. Whereas many reports have demonstrated enhanced ethylene production in metal-exposed plants, the underlying molecular mechanisms are only recently investigated. Increasing evidence supports a role for ethylene in the regulation of plant metal stress responses. Moreover, crosstalk appears to exist between ethylene and the cellular redox balance, nutrients and other phytohormones. This review highlights our current understanding of the key role ethylene plays during responses to metal exposure. Moreover, particular attention is paid to the integration of ethylene within the broad network of plant responses to metal stress. PMID:26870052

  4. Ozone-induced ethylene release from leaf surfaces

    SciTech Connect

    Rodecap, K.D.; Tingey, D.T.

    1986-01-01

    Ozone-induced stress-ethylene emissions from the adaxial and abaxial leaf surfaces of four plant species (Glycine max (L) Merr. cv. Dare, Lycopersicon esculentum Mill cv. Roma VF, Eucalyptus globulus Labill. and Hedera helix L.) were studied to determine if the stress ethylene diffused through the stomata or cuticle. In plants not exposed to ozone, basal ethylene was detected above both the adaxial and abaxial leaf surfaces of all the plant species examined, indicating that some ethylene can diffuse across the leaf cuticle. Oxone-induced stress ethylene production in all species examined. These data indicate that ozone-induced stress ethylene primarily diffuses from the leaf via the stomata.

  5. Ethylene and Metal Stress: Small Molecule, Big Impact

    PubMed Central

    Keunen, Els; Schellingen, Kerim; Vangronsveld, Jaco; Cuypers, Ann

    2016-01-01

    The phytohormone ethylene is known to mediate a diverse array of signaling processes during abiotic stress in plants. Whereas many reports have demonstrated enhanced ethylene production in metal-exposed plants, the underlying molecular mechanisms are only recently investigated. Increasing evidence supports a role for ethylene in the regulation of plant metal stress responses. Moreover, crosstalk appears to exist between ethylene and the cellular redox balance, nutrients and other phytohormones. This review highlights our current understanding of the key role ethylene plays during responses to metal exposure. Moreover, particular attention is paid to the integration of ethylene within the broad network of plant responses to metal stress. PMID:26870052

  6. The Products of Manganese (II) Oxidation

    SciTech Connect

    Perkins, A.

    2004-09-03

    Manganese, the second most abundant transition metal in the earth's crust, exists in a number of oxidation states, among which the II, III, and IV oxidation states are of greatest environmental importance. Produced through microbial activity, manganese oxides help to mediate redox reactions with organic and inorganic compounds and help to sequester a variety of metals. The mechanism by which Manganese (II) is oxidized to Manganese (IV) is a biologically catalyzed process. There are at least three different pathways by which Mn(II) can be bacterially oxidized to Mn(IV); the first in which states that Mn(II) can be oxidized to mixed Mn(III, IV), and Mn(IV) oxides and oxyhydroxides. The second of these pathways is that Mn(II) can be directly oxidized to Mn(IV) and the last of these pathways is that Mn(II) follows an enzymatic bond with a Mn(III) intermediate in which Mn(II) oxidizes to Mn(III) and then to Mn(IV). The pathways of focus for this research are the latter two pathways.

  7. Production of microspheres of thorium oxide, uranium oxide and plutonium oxide and their mixtures containing carbon

    SciTech Connect

    Bezzi, G.; Facchini, A.; Martignani, G.; Pastore, M.

    1980-05-13

    A process is desclosed for the production of microspheres of thorium oxide, uranium oxide or plutonium oxide and mixtures thereof, containing carbon. The microspheres are prepared by first forming an aqueous alkaline solution of a salt of said metals which will precipitate to a solid form in a concentrated alkaline medium together with an alkaline polymerizable organic monomer and carbon, thereafter dripping this solution into a concentrated alkaline medium wherein metal hydroxide is precipitated out and said monomers polymerized to thereby form said microspheres. The precipitated metal compounds with polymerized monomer and carbon are washed to remove unwanted ions and dried by various methods such as air currents, infrared lamps, high frequency microwaves or preferably by azeotropic distillation whereby the washed particles are dispersed in an organic liquid immiscible with water which is then boiled off. Simple liquids include 1,1,1-trichloroethane, carbontetrachloride and xylene. The particles are then subjected to thermal treatments which vary according to the particular composition and the properties required in the final product. The microspheres obtained according to the process of the invention possess excellent properties of high density, good homogeneity, and high tensile strength and are useful as fuel for high temperature gas-cooled nuclear reactors. In a preferred embodiment, uranyl nitrate is mixed with acrolein in dilute ammonia solution to which carbon is added and the solution dripped into a concentrated alkaline medium, and the microspheres thereby formed washed with water, dried by azeotropic distillation with an organic liquid, and thermally cycled.

  8. Ethylene and flower longevity in Alstroemeria: relationship between tepal senescence, abscission and ethylene biosynthesis.

    PubMed

    Wagstaff, Carol; Chanasut, Usawadee; Harren, Frans J M; Laarhoven, Luc-Jan; Thomas, Brian; Rogers, Hilary J; Stead, Anthony D

    2005-03-01

    Senescence of floral organs is broadly divided into two groups: those that exhibit sensitivity to exogenous ethylene and those that do not. Endogenous ethylene production from the former group is via a well-characterized biochemical pathway and is either due to developmental or pollination-induced senescence. Many flowers from the order Liliales are characterized as ethylene-insensitive since they do not appear to produce endogenous ethylene, or respond to exogenous ethylene treatments, however, the majority of cases studied are wilting flowers, rather than those where life is terminated by perianth abscission. The role of ethylene in the senescence and abscission of Alstroemeria peruviana cv. Rebecca and cv. Samora tepals was previously unclear, with silver treatments recommended for delaying leaf rather than flower senescence. In the present paper the effects of exogenous ethylene, 2-chloroethylphosphonic acid (CEPA) and silver thiosulphate (STS) treatments on tepal senescence and abscission have been investigated. Results indicate that sensitivity to ethylene develops several days after flower opening such that STS only has a limited ability to delay tepal abscission. Detachment force measurements indicate that cell separation events are initiated after anthesis. Endogenous ethylene production was measured using laser photoacoustics and showed that Alstroemeria senesce independently of ethylene production, but that an extremely small amount of ethylene (0.15 nl flower(-1) h(-1)) is produced immediately prior to abscission. Investigation of the expression of genes involved in ethylene biosysnthesis by semi-quantitative RT-PCR indicated that transcriptional regulation is likely to be at the level of ACC oxidase, and that the timing of ACC oxidase gene expression is coincident with development of sensitivity to exogenous ethylene. PMID:15689338

  9. Effects of Salts and Ionic Liquids on the Thermodynamics of Poly(ethylene oxide)-Containing Block Copolymers

    NASA Astrophysics Data System (ADS)

    Wanakule, Nisita; Virgili, Justin; Teran, Alexander; Balsara, Nitash

    2010-03-01

    We explore the thermodynamics of block copolymers doped with the salt, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and the ionic liquid, imidazolium bis(trifluoromethanesulfonyl) imide ([Im][TFSI]). The block copolymers comprise of polyethylene oxide (PEO), a polymer with a higher dielectric constant, and polystyrene (PS), a polymer with a lower dielectric constant. A combination of small-angle x-ray scattering (SAXS) and birefringence was used to determine morphology and order-to-disorder transition temperatures (ODT). Leibler's theory for microphase separation was employed to determine the effective Flory-Huggins interaction parameter. These values are compared to theoretically-determined values of the effective interaction parameter which were calculated with no adjustable parameters using a theory developed by Zhen-Gang Wang.

  10. Oxidation of dimethylselenide by δMnO2: oxidation product and factors affecting oxidation rate

    USGS Publications Warehouse

    Wang, Bronwen; Burau, Richard G.

    1995-01-01

    Volatile dimethylselenide (DMSe) was transformed to a nonvolatile Se compound in a ??-MnO2 suspension. The nonvolatile product was a single compound identified as dimethylselenoxide based on its mass spectra pattern. After 24 h, 100% of the DMSe added to a ??-MnO2 suspension was converted to nonpurgable Se as opposed to 20%, 18%, and 4% conversion for chromate, permanganate, and the filtrate from the suspension, respectively. Manganese was found in solution after reaction. These results imply that the reaction between manganese oxide and DMSe was a heterogeneous redox reaction involving solid phase ??-MnO2 and solution phase DMSe. Oxidation of DMSe to dimethylselenoxide [OSe(CH3)2] by a ??-MnO2 suspension appears to be first order with respect to ??-MnO2, to DMSe, and to hydrogen ion with an overall rate law of d[OSe(CH3)2 ]/dt = 95 M-2 min-1 [MnO2]1[DMSe]1[H+]1 for the MnO2 concentration range of 0.89 ?? 10-3 - 2.46 ?? 10-3 M, the DMSe concentration range of 3.9 ?? 10-7 - 15.5 ?? 10-7 M Se, and a hydrogen ion concentation range of 7.4 ?? 10-6 -9.5 ?? 10-8 M. A general surface site adsorption model is consistent with this rate equation if the uncharged |OMnOH is the surface adsorption site. DMSe acts as a Lewis base, and the manganese oxide surface acts as a Lewis acid. DMSe adsorption to |OMnOH can be viewed as a Lewis acid/ base complex between the largely p orbitals of the DMSe lone pair and the unoccupied eg orbitals on manganese oxide. For such a complex, frontier molecular orbital theory predicts electron transfer to occur via an inner-sphere complex between the DMSe and the manganese oxide. ?? 1995 American Chemical Society.

  11. Techno-economic assessment of a wood-based biorefinery concept for the production of polymer-grade ethylene, organosolv lignin and fuel.

    PubMed

    Nitzsche, Roy; Budzinski, Maik; Gröngröft, Arne

    2016-01-01

    Lignocellulose biorefineries are distinguished by an explicitly integrative, multi-functional concept that transforms biomass into multiple products, using a variety of conversion and separation processes. This study focuses on the technical design and economic evaluation of a lignocellulose biorefinery, that converts 400,000tDM/a (≙250MW) of beech wood into chemicals and fuel. A model was simulated with Aspen Plus® including the process steps pre-treatment, enzymatic hydrolysis, alcoholic fermentation, dehydration and biogas generation and upgrading. Mass and energy balances showed that 61,600t/a polymer-grade ethylene, 58,520tDM/a organosolv lignin, 38,400t/a biomethane and 90,800tDM/a hydrolysis lignin can be produced with a total energy efficiency of 87.1%. A discounted cash flow analysis indicated that the heat integrated biorefinery concept is not yet profitable. However, the economic results are greatly sensitive regarding various assumptions, in particular in terms of the prices for beech wood, ethylene and organosolv lignin. PMID:26609950

  12. Inhibiting ethylene perception with 1-methylcyclopropene triggers molecular responses aimed to cope with cell toxicity and increased respiration in citrus fruits.

    PubMed

    Establés-Ortiz, Beatriz; Romero, Paco; Ballester, Ana-Rosa; González-Candelas, Luis; Lafuente, María T

    2016-06-01

    The ethylene perception inhibitor 1-methylcyclopropene (1-MCP) has been critical in understanding the hormone's mode of action. However, 1-MCP may trigger other processes that could vary the interpretation of results related until now to ethylene, which we aim to understand by using transcriptomic analysis. Transcriptomic changes in ethylene and 1-MCP-treated 'Navelate' (Citrus sinensis L. Osbeck) oranges were studied in parallel with changes in ethylene production, respiration and peel damage. The effects of compounds modifying the levels of the ethylene co-product cyanide and nitric oxide (NO) on fruit physiology were also studied. Results suggested that: 1) The ethylene treatment caused sub-lethal stress since it induced stress-related responses and reduced peel damage; 2) 1-MCP induced ethylene-dependent and ethylene-independent responsive networks; 3) 1-MCP triggered ethylene overproduction, stress-related responses and metabolic shifts aimed to cope with cell toxicity, which mostly affected to the inner part of the peel (albedo); 4) 1-MCP increased respiration and drove metabolism reconfiguration for favoring energy conservation but up-regulated genes related to lipid and protein degradation and triggered the over-expression of genes associated with the plasma membrane cellular component; 5) Xenobiotics and/or reactive oxygen species (ROS) might act as signals for defense responses in the ethylene-treated fruit, while their uncontrolled generation would induce processes mimicking cell death and damage in 1-MCP-treated fruit; 6) ROS, the ethylene co-product cyanide and NO may converge in the toxic effects of 1-MCP. PMID:26990405

  13. Ethylene process design optimization

    SciTech Connect

    2001-09-01

    Integration of Advanced Technologies will Update Ethylene Plants. Nearly 93 million tons of ethylene are produced annually in chemical plants worldwide, using an energy intensive process that consumes 2.5 quadrillion Btu per year.

  14. 7Li NMR spectroscopy and ion conduction mechanism in mesoporous silica (SBA-15) composite poly(ethylene oxide) electrolyte

    NASA Astrophysics Data System (ADS)

    Reddy, M. Jaipal; Chu, Peter P.

    A composite of mesoporous silica (SBA-15) with a polyethylene oxide (PEO) polymer electrolyte is examined for use in various electrochemical devices. Incorporation of SBA-15 in a PEO:LiClO 4 polymer electrolyte facilitates salt dissociation, enhances ion conductivity, and improves miscibility between organic and inorganic moieties. Optimized conductivity is found at 10 wt.% SBA-15 composition, above this concentration the conductivity is reduced due to aggregation of a SBA-15:Li rich phase. Heating above melt temperature of PEO allows more of the polymer segments to interact with SBA-15. This results in a greater degree of disorder upon cooling, and the ion conductivity is enhanced. A 7Li MAS NMR study reveals three types of lithium-ion coordination. Two major types of conduction mechanism can be identified: one through conventional amorphous PEO; a second via hopping in a sequential manner by replacing the nearby vacancies ('holes') on the surface (both interior and exterior) of the SBA-15 channels.

  15. Atmospheric ethylene concentrations in research and commercial potato storages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ethylene has detrimental effects on product quality for many vegetables. Because of this, atmospheric ethylene content is monitored and managed in many vegetable storage facilities. Comparable monitoring is not done in potato storages and, as a consequence, the concentration of ethylene present in t...

  16. Assessing the allelotypic effect of two aminocyclopropane carboxylic acid synthase-encoding genes MdACS1 and MdACS3a on fruit ethylene production and softening in Malus

    PubMed Central

    Dougherty, Laura; Zhu, Yuandi; Xu, Kenong

    2016-01-01

    Phytohormone ethylene largely determines apple fruit shelf life and storability. Previous studies demonstrated that MdACS1 and MdACS3a, which encode 1-aminocyclopropane-1-carboxylic acid synthases (ACS), are crucial in apple fruit ethylene production. MdACS1 is well-known to be intimately involved in the climacteric ethylene burst in fruit ripening, while MdACS3a has been regarded a main regulator for ethylene production transition from system 1 (during fruit development) to system 2 (during fruit ripening). However, MdACS3a was also shown to have limited roles in initiating the ripening process lately. To better assess their roles, fruit ethylene production and softening were evaluated at five time points during a 20-day post-harvest period in 97 Malus accessions and in 34 progeny from 2 controlled crosses. Allelotyping was accomplished using an existing marker (ACS1) for MdACS1 and two markers (CAPS866 and CAPS870) developed here to specifically detect the two null alleles (ACS3a-G289V and Mdacs3a) of MdACS3a. In total, 952 Malus accessions were allelotyped with the three markers. The major findings included: The effect of MdACS1 was significant on fruit ethylene production and softening while that of MdACS3a was less detectable; allele MdACS1–2 was significantly associated with low ethylene and slow softening; under the same background of the MdACS1 allelotypes, null allele Mdacs3a (not ACS3a-G289V) could confer a significant delay of ethylene peak; alleles MdACS1–2 and Mdacs3a (excluding ACS3a-G289V) were highly enriched in M. domestica and M. hybrid when compared with those in M. sieversii. These findings are of practical implications in developing apples of low and delayed ethylene profiles by utilizing the beneficial alleles MdACS1-2 and Mdacs3a. PMID:27231553

  17. Assessing the allelotypic effect of two aminocyclopropane carboxylic acid synthase-encoding genes MdACS1 and MdACS3a on fruit ethylene production and softening in Malus.

    PubMed

    Dougherty, Laura; Zhu, Yuandi; Xu, Kenong

    2016-01-01

    Phytohormone ethylene largely determines apple fruit shelf life and storability. Previous studies demonstrated that MdACS1 and MdACS3a, which encode 1-aminocyclopropane-1-carboxylic acid synthases (ACS), are crucial in apple fruit ethylene production. MdACS1 is well-known to be intimately involved in the climacteric ethylene burst in fruit ripening, while MdACS3a has been regarded a main regulator for ethylene production transition from system 1 (during fruit development) to system 2 (during fruit ripening). However, MdACS3a was also shown to have limited roles in initiating the ripening process lately. To better assess their roles, fruit ethylene production and softening were evaluated at five time points during a 20-day post-harvest period in 97 Malus accessions and in 34 progeny from 2 controlled crosses. Allelotyping was accomplished using an existing marker (ACS1) for MdACS1 and two markers (CAPS866 and CAPS870) developed here to specifically detect the two null alleles (ACS3a-G289V and Mdacs3a) of MdACS3a. In total, 952 Malus accessions were allelotyped with the three markers. The major findings included: The effect of MdACS1 was significant on fruit ethylene production and softening while that of MdACS3a was less detectable; allele MdACS1-2 was significantly associated with low ethylene and slow softening; under the same background of the MdACS1 allelotypes, null allele Mdacs3a (not ACS3a-G289V) could confer a significant delay of ethylene peak; alleles MdACS1-2 and Mdacs3a (excluding ACS3a-G289V) were highly enriched in M. domestica and M. hybrid when compared with those in M. sieversii. These findings are of practical implications in developing apples of low and delayed ethylene profiles by utilizing the beneficial alleles MdACS1-2 and Mdacs3a. PMID:27231553

  18. Structural effect of glyme-Li(+) salt solvate ionic liquids on the conformation of poly(ethylene oxide).

    PubMed

    Chen, Zhengfei; McDonald, Samila; Fitzgerald, Paul A; Warr, Gregory G; Atkin, Rob

    2016-06-01

    The conformation of 36 kDa polyethylene oxide (PEO) dissolved in three glyme-Li(+) solvate ionic liquids (SILs) has been investigated by small angle neutron scattering (SANS) and rheology as a function of concentration and compared to a previously studied SIL. The solvent quality of a SIL for PEO can be tuned by changing the glyme length and anion type. Thermogravimetric analysis (TGA) reveals that PEO is dissolved in the SILs through Li(+)-PEO coordinate bonds. All SILs (lithium triglyme bis(trifluoromethanesulfonyl)imide ([Li(G3)]TFSI), lithium tetraglyme bis(pentafluoroethanesulfonyl)imide ([Li(G4)]BETI), lithium tetraglyme perchlorate ([Li(G4)]ClO4) and the recently published [Li(G4)]TFSI) are found to be moderately good solvents for PEO but solvent quality decreases in the order [Li(G4)]TFSI ∼ [Li(G4)]BETI > [Li(G4)]ClO4 > [Li(G3)]TFSI due to decreased availability of Li(+) for PEO coordination. For the same glyme length, the solvent qualities of SILs with TFSI(-) and BETI(-) anions ([Li(G4)]TFSI and [Li(G4)]BETI) are very similar because they weakly coordinate with Li(+), which facilitates Li(+)-PEO interactions. [Li(G4)]ClO4 presents a poorer solvent environment for PEO than [Li(G4)]BETI because ClO4(-) binds more strongly to Li(+) and thereby hinders interactions with PEO. [Li(G3)]TFSI is the poorest PEO solvent of these SILs because G3 binds more strongly to Li(+) than G4. Rheological and radius of gyration (Rg) data as a function of PEO concentration show that the PEO overlap concentrations, c* and c**, are similar in the three SILs. PMID:27189677

  19. In situ immobilization of proteins and RGD peptide on polyurethane surfaces via poly(ethylene oxide) coupling polymers for human endothelial cell growth.

    PubMed

    Wang, Dong-an; Ji, Jian; Sun, Yong-hong; Shen, Jia-cong; Feng, Lin-xian; Elisseeff, Jennifer H

    2002-01-01

    A "CBABC"-type pentablock coupling polymer, mesylMPEO, was designed and synthesized to promote human endothelial cell growth on the surfaces of polyurethane biomaterials. The polymer was composed of a central 4,4'-methylenediphenyl diisocyanate (MDI) coupling unit and poly(ethylene oxide) (PEO) spacer arms with methanesulfonyl (mesyl) end groups pendent on both ends. As the presurface modifying additive (pre-SMA), the mesylMPEO was noncovalently introduced onto the poly(ether urethane) (PEU) surfaces by dip coating, upon which the protein/peptide factors (gelatin, albumin, and arginine-glycine-aspartic acid tripeptide [RGD]) were covalently immobilized in situ by cleavage of the original mesyl end groups. The pre-SMA synthesis and PEU surface modification were characterized using nuclear magnetic resonance spectroscopy ((1)H NMR), attenuated total reflection infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). Human umbilical vein endothelial cells (HUVEC) were harvested manually by collagenase digestion and seeded on the modified PEU surfaces. Cell adhesion ratios (CAR) and cell proliferation ratios (CPR) were measured using flow cytometry, and the individual cell viability (ICV) was determined by MTT assay. The cell morphologies were investigated by optical inverted microscopy (OIM) and scanning electrical microscopy (SEM). The gelatin- and RGD-modified surfaces were HUVEC-compatible and promoted HUVEC growth. The albumin-modified surfaces were compatible but inhibited cell adhesion. The results also indicated that, for HUVEC in vitro cultivation, the cell adhesion stage was of particular importance and had a significant impact on the cell responses to the modified surfaces. PMID:12425667

  20. Dynamics of poly(ethylene oxide) in a blend with poly(methyl methacrylate): a quasielastic neutron scattering and molecular dynamics simulations study.

    PubMed

    Genix, A-C; Arbe, A; Alvarez, F; Colmenero, J; Willner, L; Richter, D

    2005-09-01

    In this paper, we have addressed the question of the dynamic miscibility in a blend characterized by very different glass-transition temperatures, Tg, for the components: poly(ethylene oxide) and poly(methyl methacrylate) (PEO/PMMA). The combination of quasielastic neutron scattering with isotopic labeling and fully atomistic molecular dynamics simulations has allowed us to selectively investigate the dynamics of the two components in the picosecond-10 nanoseconds scale at temperatures close and above the Tg of the blend. The main focus was on the PEO component, i.e., that of the lowest Tg, but first we have characterized the dynamics of the other component in the blend and of the pure PEO homopolymer as reference. In the region investigated, the dynamics of PMMA in the blend is strongly affected by the alpha-methyl rotation; an additional process detected in the experimental window 65 K above the blend-Tg can be identified as the merged alphabeta process of this component that shows strong deviations from Gaussian behavior. On the other hand, pure PEO displays entropy driven dynamics up to very large momentum transfers. Such kind of motion seems to freeze when the PEO chains are in the blend. There, we have directly observed a very heterogeneous and moreover confined dynamics for the PEO component. The presence of the hardly moving PMMA matrix leads to the creation of little pockets of mobility where PEO can move. The characteristic size of such confined islands of mobility might be estimated to be of approximately 1 nm. These findings are corroborated by the simulation study, which has been an essential support and guide in our data analysis procedure. PMID:16241474