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Sample records for ethylene oxide gas

  1. 21 CFR 880.6860 - Ethylene oxide gas sterilizer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ethylene oxide gas sterilizer. 880.6860 Section... Miscellaneous Devices § 880.6860 Ethylene oxide gas sterilizer. (a) Identification. An ethylene gas sterilizer is a nonportable device intended for use by a health care provider that uses ethylene oxide (ETO)...

  2. 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... Miscellaneous Devices § 880.6860 Ethylene oxide gas sterilizer. (a) Identification. An ethylene gas sterilizer is a nonportable device intended for use by a health care provider that uses ethylene oxide (ETO)...

  3. 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... Miscellaneous Devices § 880.6860 Ethylene oxide gas sterilizer. (a) Identification. An ethylene gas sterilizer is a nonportable device intended for use by a health care provider that uses ethylene oxide (ETO)...

  4. 21 CFR 880.6860 - Ethylene oxide gas sterilizer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ethylene oxide gas sterilizer. 880.6860 Section... Miscellaneous Devices § 880.6860 Ethylene oxide gas sterilizer. (a) Identification. An ethylene gas sterilizer is a nonportable device intended for use by a health care provider that uses ethylene oxide (ETO)...

  5. 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... Miscellaneous Devices § 880.6860 Ethylene oxide gas sterilizer. (a) Identification. An ethylene gas sterilizer is a nonportable device intended for use by a health care provider that uses ethylene oxide (ETO)...

  6. 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... required to remove residual ethylene oxide (ETO) from wrapped medical devices that have undergone...

  7. 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... required to remove residual ethylene oxide (ETO) from wrapped medical devices that have undergone...

  8. 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... required to remove residual ethylene oxide (ETO) from wrapped medical devices that have undergone...

  9. 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... required to remove residual ethylene oxide (ETO) from wrapped medical devices that have undergone...

  10. 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... required to remove residual ethylene oxide (ETO) from wrapped medical devices that have undergone...

  11. Ethylene Oxide Gas Sterilization of Medical Devices.

    PubMed

    Shintani, Hideharu

    2017-01-01

     Ethylene oxide gas is an agent in the sterilization of medical devices due to its effectiveness and compatibility with most materials. The advantages and disadvantages, as well as its recommended uses, are explored in this review article. The variables and their relevance on process optimization are described, the types of processing cycles are detailed and emphasis is given to the design and validation of the sterilization process.

  12. 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.

  13. Ethylene oxide

    Integrated Risk Information System (IRIS)

    EPA / 635 / R - 16 / 350Fc www.epa.gov / iris Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide EXECUTIVE SUMMARY ( CASRN 75 - 21 - 8 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) December 201 6 National Center for Environmental Assessment Office

  14. Ethylene Oxide Gaseous Sterilization

    PubMed Central

    Ernst, Robert R.; Shull, James J.

    1962-01-01

    The relationships of reaction temperature and concentration of gaseous ethylene oxide to the time required for inactivation of air-dried Bacillus subtilis var. niger spores are more complex than previously reported. A plot of temperature vs. the logarithm of “thermochemical death time” (TCDT) resulted in a straight line between 18 and 57 C for systems of “high” ethylene oxide concentration. The TCDT values were independent of ethylene oxide concentrations above certain temperature-dependent limits. A given ethylene oxide concentration produced a TCDT curve identical in the upper temperature regions with that for higher concentrations. As the temperature was lowered beyond a critical point, this curve diverged from that for higher concentrations, as a straight line of lesser slope. Thus, a series of curves exists for a range of ethylene oxide concentrations. They are characterized by two segments, both logarithmic, intersecting at a critical temperature for each concentration. The intersecting point is at a temperature inversely related to the ethylene oxide gas concentration. The temperature quotient for the high temperature segments of all systems was 1.8. This value was characteristic for ethylene oxide concentrations of 440 and 880 mg/liter at temperatures above 40.6 and 33.4 C, respectively. Below these critical temperatures, the Q10 values for the respective systems were 3.2 and 2.3. PMID:13890659

  15. Ethylene Oxide Gaseous Sterilization

    PubMed Central

    Ernst, Robert R.; Shull, James J.

    1962-01-01

    The duration of the equilibration period between admission of water vapor and subsequent introduction of gaseous ethylene oxide to an evacuated sterilizer chamber was studied with respect to its effect on the inactivation of spores of Bacillus subtilis var. niger under simulated practical conditions. Introduction of a water-adsorbing cotton barrier between the spores and an incoming gas mixture of water vapor and ethylene oxide caused a marked increase in the observed thermochemical death time of the spore populations. This effect was negated by admission of water vapor one or more minutes prior to introduction of ethylene oxide gas. Increases in temperature and relative humidity of the system promoted passage of water vapor through the cotton barriers and diminished their effect. PMID:13890660

  16. Compliance problems solved by ethylene oxide scrubber at specialty gas plant

    SciTech Connect

    Not Available

    1986-01-01

    A specialty gas producer was confronted with an EPA compliance problem in dealing with ethylene oxide (EtO). The chemical had been added to the toxicity lists of the US EPA and the Occupational Safety and Health Administration (OSHA). Effective August 21, 1984, the OSHA standard for EtO limited exposure to a 1 ppm, eight-hour time weighted average. Ethylene oxide is used to sterilize many pharmaceutical and hospital supplies. Typically, EtO is supplied in cylinders as a mixture with Freon-12 or carbon dioxide. A standard cylinder contains 135 lb of product, of which about 16 lb is EtO. When a customer is finished with an EtO cylinder, it is returned to the specialty gas producer. Before recharging a cylinder, it must be purged of any remaining EtO and then cleaned. The purged EtO presented a problem in removal and disposal. An ethylene oxide scrubbing system was designed for the gas cylinder area. It consists of a specially designed 28 ft packed tower, a 400 gal holding tank, valves, and recirculation pump. Gas purged from returned EtO cylinders is directed to the scrubber and is channelled upward through the packed bed as scrubbing liquid flows countercurrently over the packing. A mist eliminator at the top of the packed bed prevents entrained liquids from escaping with the vent gas. The water soluble EtO is hydrolized to ethylene alcohol and then to ethylene glycol, a relatively inert and harmless chemical.

  17. Selective removal of ethylene, a deposit precursor, from a "dirty" synthesis gas stream via gas-phase partial oxidation.

    PubMed

    Villano, Stephanie M; Hoffmann, Jessica; Carstensen, Hans-Heinrich; Dean, Anthony M

    2010-06-17

    A fundamental issue in the gasification of biomass is that in addition to the desired synthesis gas product (a mixture of H(2) and CO), the gasifier effluent contains other undesirable products that need to be removed before any further downstream processing can occur. This work assesses the potential to selectively remove hydrocarbons from a synthesis gas stream via gas-phase partial oxidation. Specifically, the partial oxidation of methane-doped, ethylene-doped, and methane/ethylene-doped model synthesis gas mixtures has been investigated at ambient pressures over a temperature range of 760-910 degrees C and at residence times ranging from 0.4 to 2.4 s using a tubular flow reactor. For the synthesis gas mixtures that contain either methane or ethylene, the addition of oxygen substantially reduces the hydrocarbon concentration while only a small reduction in the hydrogen concentration is observed. For the synthesis gas mixtures doped with both methane and ethylene, the addition of oxygen preferentially removes ethylene while the concentrations of methane and hydrogen remain relatively unaffected. These results are compared to the predictions of a plug flow model using a reaction mechanism that is designed to describe the pyrolysis and partial oxidation of small hydrocarbon species. The agreement between the experimental observations and the model predictions is quite good, allowing us to explore the underlying chemistry that leads to the hydrocarbon selective oxidation. The implications of these results are briefly discussed in terms of using synthesis gas to produce liquid fuels and electrical power via a solid oxide fuel cell.

  18. [The influence of load size on the result of ethylene oxide gas sterilization].

    PubMed

    Jakimiak, B

    1995-01-01

    The purpose of the study was establishing whether the size of the load--that is the degree of filling of sterilizer chamber with medical instruments--could have an effect on the time needed for eradication of all microorganisms subjected to the action of ethylene oxide. The test organism used was the strain of Bacillus subtilis var. niger ATTC 9372. Tests were prepared with about 3.6 x 10(6) spores per one test. The tested samples were exposed to ethylene oxide at concentration of 750 mg/l, at 50-80 degrees C, at 40% humidity during 30, 60, 120, 180, 240 and 300 minutes in three variants: in empty sterilizer chamber im chamber loaded with plastic objects (polyethylene and polypropylene)--600 g weight in chamber with similar load weighing 1200 g. The obtained results showed that the degree of filling of sterilizer chamber influenced the efficiency of gas sterilization with ethylene oxide. The effectiveness of each sterilization process with ethylene oxide should be controlled using biological indicators.

  19. [Calculation of flammability limits of gas phases with ethylene oxide in sterilisers].

    PubMed

    Askar, Enis; Schröder, Volkmar; Acikalin, Aydan; Steinbach, Jörg

    2008-12-01

    A calculation method for flammability limits of gas phases with ethylene oxide in sterilisers was developed. Using the Software GasEq and the newly developed Makro "SterEx" for MS-Excel, flammability limits of mixtures with ethylene oxide, air and inert gases at temperatures between 20 degrees C and 100 degrees C and pressures between 0.4 bar and 1.0 bar can be calculated. This method can be used to easily determine safe operating conditions. The used semi-empirical model is based upon the assumption of constant flame temperature profiles at the flammability limits subject to the EO-concentration for different mixtures. To collect model parameters and to validate the model, several experiments with mixtures of ethylene oxide, nitrogen, carbon dioxide, water vapour and air were carried out to determine flammability limits. To simulate the structural conditions of sterilisers, the experiments were conducted in accordance to DIN EN 1839-B in a closed autoclave with temperatures and pressures relevant for sterilisation processes. The calculation of flammability limits of process gas mixtures with "SterEx" provides good agreement with flammability limits that were determined in experiments.

  20. Personal exposure level and environmental ethylene oxide gas concentration in sterilization facilities of hospitals in Japan.

    PubMed

    Hori, Hajime; Yahata, Katsuya; Fujishiro, Kazuya; Yoshizumi, Koji; Li, Ding; Goto, Yoshiaki; Higashi, Toshiaki

    2002-09-01

    Personal and environmental (stationary) ethylene oxide (EO) gas concentrations in gas sterilization facilities were measured at six workplaces in five hospitals. An ethylene oxide gas monitor (3M #3551) was used for both personal and stationary samplings. A gas detector tube was also used for instantaneous sampling. In most workplaces, the personal exposure levels of EO were below the detection limit of the gas monitor. Most of the time-weighted average (TWA) concentrations by the stationary sampling were below the threshold limit value of EO (TLV-TWA = 1 ppm), but in one workplace, more than 4 ppm of EO were detected in front of the sterilizer in a clean room during a 24-hour measurement, although all the personal exposure levels were below the detection limit. Method of aeration after the sterilization was very important for reducing the EO exposure. The EO gas concentrations in two workplaces where sufficient aeration was carried out were below the detection limit in all the stationary samples. In one workplace where insufficient aeration was performed, EO was detected from 16 of 17 stationary samples, and more than 90-200 ppm of EO was determined by the gas detector tube near the worker's face at the moment when the door of the sterilizer was opened and the sterilized materials were removed.

  1. Bacterial killing ability of 10% ethylene oxide plus 90% hydrochlorofluorocarbon sterilizing gas.

    PubMed

    Alfa, M J; DeGagne, P; Olson, N

    1997-09-01

    To use a serum and salt challenge in narrow-lumen carriers to evaluate a 10% ethylene oxide plus 90% hydrochlorofluorocarbon (EO-HCFC) sterilant mixture in a retrofitted 12/88 sterilizer as an alternative to the banned chlorofluorocarbon-ethylene oxide (EO) sterilant mixture. An EO-HCFC sterilizing gas mixture in a retrofitted 12/88 sterilizer was compared to 100% ethylene oxide (100% EO) sterilizing gas to determine its relative ability to kill seven different bacteria (Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Bacillus subtilis spores, Bacillus stearothermophilus spores, Bacillus circulans spores, and Mycobacterium chelonei) in the presence or absence of a combined 10% serum and 0.65% salt challenge using both penicylinders (PC) and long narrow-lumen (LU) carriers. The EO-HCFC sterilant mixture (96% sterile carriers) was equivalent to the 100% EO sterilant (98% sterile carriers) for killing vegetative organisms, as well as spore suspensions, on the 27 PC and 27 LU carriers in the absence of serum and salt. In the presence of serum and salt, the EO-HCFC sterilant mixture was markedly better than the 100% EO sterilant at reducing the bacterial load on the 63 PC carriers (95% vs 62% sterile PC carriers, respectively), whereas both sterilizers were equivalent for the 63 LU carriers (49% vs 40% sterile LU carriers, respectively). Of the seven test organisms, E faecalis, B subtilis, B stearothermophilus, and B circulans were the most difficult to kill for both PC and LU carriers when serum and salt were present. The data presented in this report indicate that the EO-HCFC sterilant mixture is an effective alternative for gas sterilization. Indeed, the efficiency of bacterial killing for the EO-HCFC sterilant mixture was similar to that achieved by the 12/88 EO-CFC sterilant mixture.

  2. Comparison of sterilization of reusable endoscopic biopsy forceps by autoclaving and ethylene oxide gas.

    PubMed

    Yoon, Jai Hoon; Yoon, Byung Chul; Lee, Hang Lak; Lee, Jun Kyu; Kim, Yong-Tae; Lee, Dong Ho; Choi, Il Ju; Lee, Don Haeng; Kim, Dong Hee

    2012-02-01

    Every country has standardized reprocessing guidelines for reducing the risk of microorganism transmission via reusable biopsy forceps. Sterilization is performed either by autoclaving or with the use of ethylene oxide (EO) gas. However, there are no clear standard global recommendations. The aim of this study was to determine whether EO gas or autoclaving is a safer and more effective method for the sterilization of reusable forceps. This was a prospective study conducted at multiple tertiary referral centers. Seventy reusable biopsy forceps that had been reused at least 20 times each were collected from six endoscopy centers. In all, 61 forceps from five centers were sterilized using EO gas, and the nine forceps from the remaining center were placed in an autoclave. We performed real-time polymerase chain reaction (RT-PCR) for Mycobacterium tuberculosis and hepatitis B virus and performed bacterial cultures on the reusable forceps, which were cut into 2- to 3-cm sections. The forceps were also scanned with an electron microscope (EM) to detect surface damage and contamination. Escherichia coli bacteria were cultured from 2 of the 61 (3.3%) reusable biopsy forceps sterilized with EO gas. On EM scanning, abundant debris and tissue materials remained on the cup surfaces of the reused biopsy forceps and on their inner wires. No microorganisms were found on the autoclaved forceps. Sterilization with EO gas may be inadequate because the complicated structure of the forceps may interfere with sterilization. Therefore, for optimum safety, reusable biopsy forceps should be sterilized by autoclaving.

  3. A comparative study of ethylene oxide gas, hydrogen peroxide gas plasma, and low-temperature steam formaldehyde sterilization.

    PubMed

    Kanemitsu, Keiji; Imasaka, Takayuki; Ishikawa, Shiho; Kunishima, Hiroyuki; Harigae, Hideo; Ueno, Kumi; Takemura, Hiromu; Hirayama, Yoshihiro; Kaku, Mitsuo

    2005-05-01

    To compare the efficacies of ethylene oxide gas (EOG), hydrogen peroxide gas plasma (PLASMA), and low-temperature steam formaldehyde (LTSF) sterilization methods. The efficacies of EOG, PLASMA, and LTSF sterilization were tested using metal and plastic plates, common medical instruments, and three process challenge devices with narrow lumens. All items were contaminated with Bacillus stearothermophilus spores or used a standard biological indicator. EOG and LTSF demonstrated effective killing of B. stearothermophilus spores, with or without serum, on plates, on instruments, and in process challenge devices. PLASMA failed to adequately sterilize materials on multiple trials in several experiments, including two of three plates, two of three instruments, and all process challenge devices. Our results suggest that PLASMA sterilization may be unsuccessful under certain conditions, particularly when used for items with complex shapes and narrow lumens. Alternatively, LTSF sterilization demonstrates excellent efficacy and is comparable to EOG sterilization. LTSF could potentially act as a substitute if EOG becomes unavailable due to environmental concerns.

  4. [Studies on the method of sterilization with ethylene oxide gas. 1. Sterilization procedure and sterilizing effect].

    PubMed

    Arimoto, H; Ukisu, S; Yamada, Y; Sano, K; Kanri, T

    1989-12-01

    Undertaken to ensure perfection of sterilization with ethylene oxide gas (EO gas) in routine clinical laboratory practice, an investigation was made of the relationship between sterilization procedure and sterilizing effect using the film bag delivery system and chamber system. Using a biological indicator as a monitor of sterilizing effect, the efficiency of sterilization was studied under various likely conditions and compared. The results led to the following conclusions: 1. Sterilization with EO gas by the film bag delivery system, because of this procedure being unable to be performed at a constant temperature, was shown to prove inadequate due to insufficient exposure to gas especially in winter season (when room temperature fell below 10 degrees C). 2. With the EO gas sterilization method using the film bag delivery system, which is believed to be effective within the ordinary range of humidity of the atmosphere, sterilizing effect was recognized to be affected by excess wetting of an object of sterilization that was caused by inadvertent manipulation or due to a predisposing attribute of the object, such as shape or outline. 3. All materials are sterilized upon being packaged. It is necessary therefore to make best choice of package material with respect of texture and size. Reuse influence to sterilizing effect. 4. The method of sterilization with EO gas using the chamber system has the advantage in that operating conditions are all automatically controlled. For this reason, there was not a single instance of failure to sterilize due to inappropriateness of temperature and humidity. From these results it is concluded that sterilising effect was affected by sterilization procedure and condition.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Impact of ethylene oxide gas sterilization of duodenoscopes after a carbapenem-resistant Enterobacteriaceae outbreak.

    PubMed

    Naryzhny, Igor; Silas, Dean; Chi, Kenneth

    2016-08-01

    Carbapenem-resistant Enterobacteriaceae (CRE) outbreaks have been implicated at several medical institutions involving gastroenterology laboratories and, specifically, duodenoscopes. Currently, there are no specific guidelines to eradicate or prevent the outbreak of this bacteria. We describe ethylene oxide (ETO) gas sterilizations of duodenoscopes to address this issue. A complete investigation of the gastroenterology laboratory and an evaluation by the Centers for Disease Control and Prevention concluded that no lapses were found in the reprocessing of the equipment. With no deficiencies to address, we began a novel cleaning process using surgical ETO gas sterilizers in addition to standard endoscope reprocessing recommendations and guidelines, all while trying to eradicate the CRE contamination and prevent future recurrences. We also instituted a surveillance system for recurrence of CRE contamination via monthly cultures of the duodenoscopes. Between October 2013 and April 2014, 589 ERCPs were performed with 645 ETO gas sterilizations of 6 duodenoscopes. Given the extra 16 hours needed to sterilize the duodenoscopes, our institution incurred costs resulting from purchasing additional equipment and surveillance cultures. Four duodenoscopes sustained damage during this period; however, this could not be directly attributed to the sterilization process. Furthermore, after an 18-month success period we encountered a positive CRE culture after sterilization, albeit of a different strain than originally detected during the outbreak. The duodenoscope underwent additional ETO gas sterilization, with a negative repeated culture; all potentially exposed individuals screened negative for CRE. Proper use of high-level disinfection alone may not eliminate multidrug-resistant organisms from duodenoscopes. In this single-center study, the addition of ETO sterilization and frequent monitoring with cultures reduced duodenoscope contamination and eliminated clinical infections

  6. Poly(ethylene glycol)-poly(L-lactide) diblock copolymer prevents aggregation of poly(L-lactide) microspheres during ethylene oxide gas sterilization.

    PubMed

    Choi, Y; Kim, S Y; Moon, M H; Kim, S H; Lee, K S; Byun, Y

    2001-05-01

    Sterilization procedure is one of the most important obstacles in the clinical applications of biodegradable microspheres. The microspheres prepared with poly(alpha-hydroxy acid) were severely aggregated during ethylene oxide (EO) gas sterilization, and could not be used in clinical applications. In this study, the effects of EO gas sterilization on the poly(L-lactide) (PLLA) microspheres were analyzed by nuclear magnetic resonance spectroscopy (1H-NMR), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), scanning electron microscope (SEM) and size fractionation. The aggregation between the microspheres might be stimulated by high mobility of amorphous regions of PLLA on the microsphere surfaces since both water vapor and gas mixture can reduce glass transition temperature (Tg) of PLLA below the sterilization temperature. During EO gas sterilization, there were no changes in the molecular structure and the molecular weight of PLLA in microspheres, but there were changes in the crystallinity of PLLA in microspheres. In this study, poly(L-lactide)-poly(ethylene glycol) diblock copolymers (PLE) were blended with PLLA homopolymers in various ratios to design the microsphere suitable for EO gas sterilization. Aggregation of PLLA microspheres was markedly prevented when more than 4wt% of PLE was blended in the microspheres. This inhibition effect on aggregation may be due to the increased initial crystallinity of the microspheres, which help to maintain the microsphere morphology during EO gas sterilization.

  7. Comparison of ion plasma, vaporized hydrogen peroxide, and 100% ethylene oxide sterilizers to the 12/88 ethylene oxide gas sterilizer.

    PubMed

    Alfa, M J; DeGagne, P; Olson, N; Puchalski, T

    1996-02-01

    The performance of a standard gas sterilizer, which uses a mixture of 12% ethylene oxide (EtO) and 88% chlorofluorocarbon as the sterilizing gas (12/88), was compared to selected gas, ion plasma, and vaporized hydrogen peroxide (H2O2) sterilizers that do not use chlorofluorocarbons. The effect of serum and salt on sterilizer performance was evaluated. Test carriers (porcelain and stainless steel penicylinders, or 125-cm lengths of plastic tubing [internal diameter of 3.2 mm]) were inoculated with Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Mycobacterium chelonei, Bacillus stearothermophilus spores, Bacillus subtilis spores, and Bacillus circulans spores and then subjected to sterilization using 12/88, 100% EtO, ion plasma, or vaporized H2O2. The bacterial inoculum was prepared with and without 10% serum and 0.65% salt, and the residual bacterial load after sterilization as determined using viable counts. All of the sterilizers tested effected a six-log10 reduction of the bacterial inoculum on penicylinders, unless 10% serum and 0.65% salt were present, in which case the 100% EtO, vaporized H2O2, and ion plasma sterilizers were not as effective as the 12/88 sterilizer. None of the sterilizers could eradicate 10(6) CFU of all of the bacteria in 10% serum and 0.65% salt when inoculated inside a narrow lumen. The margin of safety for the 100% EtO, vaporized H2O2, and ion plasma sterilizers is less than that of the 12/88 sterilizer. The inability of all sterilizers, including the 12/88, to kill organisms in narrow lumens reliably when serum and salt were present raises concern about the current practice of gas sterilization of flexible endoscopes.

  8. Current Toxicology of Ethylene Oxide,

    DTIC Science & Technology

    1982-12-01

    carcinogenicity are presented. The overall toxicological implications and a recommendation on the use of ethylene oxide are briefly discussed. (U...wer exposed to ethylene oxide vapour. A single exposure of the male rats to vapour at 100 ppm for 4 hours resulted in reproduction A abnormalities...oxide causes leukemia. It should be noted also that ethylene oxide in the presence of water produces ethylene glycol. Subchronic and chronic exposures

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

    PubMed

    Boiano, James M; Steege, Andrea L

    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. Modular, web-based survey. 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. Descriptive analyses were conducted including simple frequencies and prevalences. 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). 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.

  10. 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

  11. Pure And Modified Co-poly(amide-12-b-ethylene oxide) Membranes For Gas Separation Studied By Molecular Investigations

    NASA Astrophysics Data System (ADS)

    Tocci, Elena; De Lorenzo, Luana; Gugliuzza, Annarosa; Macchione, Marialuigia; Drioli, Enrico

    2010-10-01

    A combined experimental and theoretical study has been performed to investigate transport properties in a pure and modified poly(amide-12-b-ethylene oxide) (PEBAX®2533) block copolymer membrane with N-ethylo,p-toluenesulphonamide (KET) as additive molecules. MD simulations using COMPASS force field, Gusev-Suter Transition State Theory (TST) and Monte Carlo methods have been used. Bulk models of PEBAX®2533 and PEBAX/KET in different copolymer/additive compositions have been assembled and analysed to evaluate gas permeability and the morphology to characterize structure-performance relationships.

  12. Effects of ethylene oxide gas sterilization on physical properties of poly(L-lactide)-poly(ethylene glycol)-poly(L-lactide) microspheres.

    PubMed

    Ah, Y C; Choi, Y; Kim, S Y; Kim, S H; Lee, K S; Byun, Y

    2001-01-01

    The aggregation of poly(alpha-hydroxy acid) microspheres during ethylene oxide (EO) gas sterilization makes it difficult for the microspheres to be used in clinical applications. In this study, six kinds of PLLA-PEG-PLLA triblock copolymers (TriPLE) were synthesized with various composition ratios of PEG/PLLA in the range of 0.012 to 0.103. TriPLE microspheres were prepared by the oil-in-water emulsion method. TriPLE microspheres were characterized by using 1H-NMR, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). After sterilization by EO gas at 55 degrees C, the microspheres were analyzed by scanning electron microscope (SEM), laser diffractometry, standard sieves, X-ray diffraction (XRD), GPC, and DSC. When the composition ratio of PEG/PLLA was above 0.02, the initial crystallinity of TriPLE in microspheres was as high as 50%, and the microspheres were suitable to be sterilized by EO gas. On the other hand, TriPLE microspheres, which had composition ratios of PEG/PLLA below 0.02, had low initial crystallinities of about 30%, and aggregated during EO gas sterilization. For these microspheres, crystallinity increased up to 50% during the sterilization, whereas other TriPLE microspheres did not show any changes in crystallinity. Therefore, the aggregation of TriPLE microspheres during EO gas sterilization was markedly reduced as the initial crystallinity of TriPLE in the microspheres was increased.

  13. Effects of sterilization with hydrogen peroxide gas plasma, ethylene oxide, and steam on bioadhesive properties of nylon and polyethylene lines used for stabilization of canine stifle joints.

    PubMed

    Gatineau, Matthieu; El-Warrak, Alexander O; Bolliger, Christian; Mourez, Michael; Berthiaume, Frederic

    2012-10-01

    To compare effects of sterilization with hydrogen peroxide gas plasma (HPGP), ethylene oxide, and steam on bioadhesive properties of nylon and polyethylene lines used for stabilization of canine stifle joints. Samples of a 36.3-kg test nylon leader line, 57.8-kg test nylon fishing line, and 2-mm ultrahigh-molecular weight polyethylene (UHMWPE) were used. In this in vitro study, samples of nylon leader line, fishing line, and UHMWPE sterilized by use of HPGP, ethylene oxide, and steam or unsterilized samples were used. Bacterial adherence on unsterilized and sterilized samples was tested with Staphylococcus epidermidis and Escherichia coli. Five samples were examined for each line type and sterilization condition, and final colony counts were obtained. Bacterial adherence was significantly affected by method of sterilization for all 3 line types. For most of the samples, bacterial adherence was similar or lower when HPGP sterilization was used, compared with results for sterilization via ethylene oxide and steam, respectively. Bacterial adherence was significantly higher for UHMWPE, compared with adherence for the nylon line, regardless of the sterilization method used. Bacterial adherence was higher for nylon fishing line than for nylon leader line for S epidermidis after ethylene oxide sterilization and for E coli after HPGP and ethylene oxide sterilization. Effects of HPGP sterilization on bioadhesive properties of nylon and polyethylene lines compared favorably with those for ethylene oxide and steam sterilization. Also, nylon line may be a more suitable material than UHMWPE for suture prostheses on the basis of bacterial adherence properties.

  14. Ethylene oxide potential toxicity.

    PubMed

    da Cunha Mendes, Gisela Cristina; da Silva Brandão, Teresa Ribeiro; Miranda Silva, Cristina Luisa

    2008-05-01

    The future of ethylene oxide (EO) sterilization has been questioned, owing to its associated toxicity. EO has been around for more than 60 years, mainly due to its recognized characteristics of reliability and effectiveness, coupled with the process flexibility, as well as its compatibility with most mechanical devices. Despite the well-known EO toxicity, the undesirable effects of medical devices' EO residues on the patient's health have not yet been well established. There are limitations related to the current risk-assessment studies. To overcome these drawbacks, demands on greater safety are increasing, which lead to improvements in sterilizers and aeration equipment, as well as the design of the processes. The paper under evaluation highlights risks related to EO sterilization of materials used during processing of stem cells for transplantation, but is an example of a study where the dose of the residues in the devices is not considered.

  15. Mortality among ethylene oxide workers.

    PubMed

    Morgan, R W; Claxton, K W; Divine, B J; Kaplan, S D; Harris, V B

    1981-11-01

    Because of reports linking an increased risk of leukemia with exposure to ethylene oxide, a mortality study of workers with potential exposure to ethylene oxide at the Texaco Chemical Company Plant in Port Neches, Tex., was undertaken. A total of 767 males with potential exposure to ethylene oxide were identified. Forty-six deaths occurred in this cohort with 80 expected (standardized mortality ratio; SMR = 58). No deaths from leukemia were seen, nor were there any statistically significant excesses from any specific causes of death.

  16. The effects of ethylene oxide and gas-plasma sterilization on failure strength and failure mode of pre-tied monofilament ligature loops.

    PubMed

    Trostle, Steven S; Hendrickson, Dean A; Franke, Chad

    2002-01-01

    To evaluate the effects of ethylene oxide and gas-plasma sterilization on the failure strength and failure mode of pre-tied monofilament ligature loops. A randomized block design was used by blocking for suture (size 1 polyglyconate, size 2 polydioxanone) and sterilization technique (control, ethylene oxide, gas plasma). Twenty replicates of each suture-sterilization technique combination. Ligature loops were pre-tied using a 4S-modified Roeder knot then exposed to 1 of 3 treatments (control, ethylene oxide, or gas-plasma sterilization). Ligature loops were mounted onto a mechanical testing machine to evaluate the effects of sterilization on failure strength and failure mode (disruption, untying). There were no differences between polydioxanone and polyglyconate suture materials in failure strength or mode within sterilization methods. Both sterilization methods significantly increased the likelihood that suture loops would untie compared with controls subjects. Ligature loops that disrupted had a greater breaking strength than those that untied, regardless of sterilization method or suture type. Sterilization with either ethylene oxide or gas plasma of pre-tied, polyglyconate, or polydioxanone ligature loops significantly increases the in vitro likelihood of a modified Roeder knot untying. Further studies need to be conducted to determine the in vivo requirements for ligature loops. Copyright 2002 by The American College of Veterinary Surgeons

  17. 46 CFR 154.1725 - Ethylene oxide.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Ethylene oxide. 154.1725 Section 154.1725 Shipping COAST....1725 Ethylene oxide. (a) A vessel carrying ethylene oxide must: (1) Have cargo piping, vent piping, and... space of an ethylene oxide cargo tank for a period of 30 days under the condition of paragraph (e)...

  18. 46 CFR 154.1725 - Ethylene oxide.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Ethylene oxide. 154.1725 Section 154.1725 Shipping COAST....1725 Ethylene oxide. (a) A vessel carrying ethylene oxide must: (1) Have cargo piping, vent piping, and... space of an ethylene oxide cargo tank for a period of 30 days under the condition of paragraph (e)...

  19. 46 CFR 154.1725 - Ethylene oxide.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Ethylene oxide. 154.1725 Section 154.1725 Shipping COAST....1725 Ethylene oxide. (a) A vessel carrying ethylene oxide must: (1) Have cargo piping, vent piping, and... space of an ethylene oxide cargo tank for a period of 30 days under the condition of paragraph (e)...

  20. Evaluation of in vitro serial antibiotic elution from meropenem-impregnated polymethylmethacrylate beads after ethylene oxide gas and autoclave sterilization.

    PubMed

    Báez, L A; Langston, C; Givaruangsawat, S; McLaughlin, R

    2011-01-01

    To determine the elution properties of meropenem and to compare the elutions of meropenem-impregnated polymethylmethacrylate (PMMA) beads without sterilization (P-M-C) to those sterilized with steam (P-M-A) and ethylene oxide gas (P-M-EO). A commercial bead mould was used to produce four groups of beads: one group without antibiotic (negative control), and three groups of meropenem-impregnated beads: P-M-C, P-M-A, and P-M-EO. The beads were placed in a phosphate buffered solution and eluent samples were collected. Concentrations of the antibiotic in eluent samples from the two sterilized groups and the control beads were determined using a microbiological assay at 1, 3, 6 and 12 hours and at 1, 2, 3, 6, 9, 12, 15, 18, 22, 26, and 30 days. The microbiological assay resulted in no zone of inhibition at all time periods for the P-M-A samples and the samples of PMMA without antimicrobial. The meropenem concentration on the eluent remained above 4 mcg/ml for 15 days in the P-M-C group and until day 18 for P-M-EO group. There was no statistical difference in AUC0-∞ (p<0.318), however significance did occur for MRT (p<0.005) when comparing P-M-C and P-M-EO with the later being higher. The meropenem incorporated in the PMMA beads eluted effectively and gradually decreased after the 24 hour peak, but remained above the concentration level of 4 mcg/ml for 15 days in the P-M-C group and until day 18 for P-M-EO group. Ethylene oxide does not adversely affect meropenem's elution from PMMA beads.

  1. 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

  2. RESIDUAL RISK ASSESSMENT: ETHYLENE OXIDE ...

    EPA Pesticide Factsheets

    This document describes the residual risk assessment for the Ethylene Oxide Commercial Sterilization source category. For stationary sources, section 112 (f) of the Clean Air Act requires EPA to assess risks to human health and the environment following implementation of technology-based control standards. If these technology-based control standards do not provide an ample margin of safety, then EPA is required to promulgate addtional standards. This document describes the methodology and results of the residual risk assessment performed for the Ethylene Oxide Commercial Sterilization source category. The results of this analyiss will assist EPA in determining whether a residual risk rule for this source category is appropriate.

  3. RESIDUAL RISK ASSESSMENT: ETHYLENE OXIDE ...

    EPA Pesticide Factsheets

    This document describes the residual risk assessment for the Ethylene Oxide Commercial Sterilization source category. For stationary sources, section 112 (f) of the Clean Air Act requires EPA to assess risks to human health and the environment following implementation of technology-based control standards. If these technology-based control standards do not provide an ample margin of safety, then EPA is required to promulgate addtional standards. This document describes the methodology and results of the residual risk assessment performed for the Ethylene Oxide Commercial Sterilization source category. The results of this analyiss will assist EPA in determining whether a residual risk rule for this source category is appropriate.

  4. Preparation of ethylene gas and comparison of ethylene responses induced by ethylene, ACC, and ethephon.

    PubMed

    Zhang, Wei; Wen, Chi-Kuang

    2010-01-01

    Ethylene is a gaseous plant hormone used in many physiological studies examining its role in plant growth and development. However, ethylene gas may not be conveniently available to many laboratories for occasional use, and therefore several chemicals can be used as replacements. Here we report that the kinetics of the ethylene response induced by ethylene and two widely-used ethylene replacements are different. ACC failed to efficiently replace prolonged ethylene treatments, while the decomposition products of ethephon may cause non-specific responses and the efficiency of ethephon conversion to ethylene was relatively low. A cost-effective method to prepare ethylene gas was developed. Analyzed by gas chromatography, the chemically produced ethylene exhibited an identical chromatogram to that from the commercial source. Our synthetic ethylene gave the same dose-response curve in Arabidopsis as gaseous ethylene. Our study shows that the use of the ethylene gas is essential to experiments that are sensitive to treatment duration and dosage. When ACC and ethephon are used as replacements, caution should be taken in the experimental design. For laboratories that do not have an ethylene tank, ethylene gas can be easily prepared by a chemical approach without further purification.

  5. 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.

  6. Effectiveness of ethylene oxide for sterilization of dental handpieces.

    PubMed

    Parker, H H; Johnson, R B

    1995-04-01

    Ethylene oxide gas has been utilized as an alternative method for sterilization of dental handpieces, as it is less corrosive than steam. However, its effectiveness for sterilization of the internal components of dental handpieces has not been established. The objective of this study was to compare the effectiveness of ethylene oxide and steam for sterilization of dental handpieces. Unused handpieces and handpieces which had been exposed to clinical dental procedures ('clinical') were contaminated with Streptococcus mutans, exposed to steam or ethylene oxide, and flushed with sterile saline. Washings were plated on mitis-salivarius agar, and colonies identified and counted. No viable colonies could be established from washings from 'clinical' or 'unused' handpieces exposed to steam. However, viable colonies could be established from 'clinical' handpieces exposed to ethylene oxide. This data suggests that a substance entrapped within 'clinical' handpieces (possibly the biofilm) may protect bacteria from ethylene oxide gas, preventing adequate sterilization.

  7. 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

  8. [A survey of ethylene oxide sterilization in a hospital].

    PubMed

    Fujishiro, K; Mori, K; Inoue, N

    1991-09-01

    The health and environmental problems of ethylene oxide gas sterilization in a hospital are reported. Eight nurses who had been engaged in the gas sterilization, sometimes operated the auto-sterilizer in an inadequate manner; they exposed more than several hundred ppm of ethylene oxide once or twice a week. The main acute effects on these nurses after massive exposure were headaches, general fatigue and irritation of the eyes and throat. But no signs of polyneuropathy were seen. This survey suggests that there is a great risk of ethylene oxide poisoning while sterilizing instruments in a hospital.

  9. Cancer mortality in ethylene oxide workers.

    PubMed Central

    Bisanti, L; Maggini, M; Raschetti, R; Alegiani, S S; Ippolito, F M; Caffari, B; Segnan, N; Ponti, A

    1993-01-01

    A cohort of 1971 chemical workers licensed to handle ethylene oxide was followed up retrospectively from 1940 to 1984 and the vital status of each subject was ascertained. No quantitative information on exposure was available and therefore cohort members were considered as presumably exposed to ethylene oxide. The cohort comprised 637 subjects allowed to handle only ethylene oxide and 1334 subjects who obtained a licence valid for ethylene oxide as well as other toxic gases. Potential confounding arising from the exposure to these other chemical agents was taken into consideration. Causes of death were found from death certificates and comparisons of mortality were made with the general population of the region where cohort members were resident. Seventy six deaths were reported whereas 98.8 were expected; the difference was statistically significant. The number of malignancies for any site exceeded the expected number (standardised mortality ratio (SMR) = 130; 43 observed deaths; 95% confidence interval (95% CI) 94-175) and approached statistical significance. For all considered cancer sites the SMRs were higher than 100 but the excess was only significant (p < 0.05, two sided test) for lymphosarcoma and reticulosarcoma (International Classification of Diseases--9th revision (ICD-9) = 200; SMR = 682; four observed deaths; 95% CI 186-1745). The excess of cases for all cancers of haematopoietic tissue (ICD-9 = 200-208) also approached statistical significance (SMR = 250; six observed deaths; 95% CI 91-544). Focusing the analysis on the subcohort of the ethylene oxide only licensed workers, who are likely to have experienced a more severe exposure to this gas, it became evident that all but one of the observed cases of haematopoietic tissue cancers in the cohort were confined to this subgroup, enhancing the relevant SMR to 700 (95% CI 237-1637) and the SMR of lymphosarcoma and reticulosarcoma to 1693 (95% CI 349-4953). PMID:8494771

  10. Novel and existing data for a future physiological toxicokinetic model of ethylene and its metabolite ethylene oxide in mouse, rat, and human.

    PubMed

    Filser, Johannes Georg; Artati, Anna; Li, Qiang; Pütz, Christian; Semder, Brigitte; Klein, Dominik; Kessler, Winfried

    2015-11-05

    The olefin ethylene is a ubiquitously found gas. It originates predominantly from plants, combustion processes and industrial sources. In mammals, inhaled ethylene is metabolized by cytochrome P450-dependent monooxygenases, particularly by cytochrome P450 2E1, to ethylene oxide, an epoxide that directly alkylates proteins and DNA. Ethylene oxide was mutagenic in vitro and in vivo in insects and mammals and carcinogenic in rats and mice. A physiological toxicokinetic model is a most useful tool for estimating the ethylene oxide burden in ethylene-exposed rodents and humans. The only published physiological toxicokinetic model for ethylene and metabolically produced ethylene oxide is discussed. Additionally, existing data required for the development of a future model and for testing its predictive accuracy are reviewed and extended by new gas uptake studies with ethylene and ethylene oxide in B6C3F1 mice and with ethylene in F344 rats.

  11. 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.

  12. 29 CFR 1915.1047 - Ethylene oxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Ethylene oxide. 1915.1047 Section 1915.1047 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1047 Ethylene oxide. Note: The requirements applicable to shipyard employment under this...

  13. 29 CFR 1926.1147 - Ethylene oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Ethylene oxide. 1926.1147 Section 1926.1147 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Ethylene oxide. Note: The requirements applicable to construction work under this section are identical...

  14. 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... § 1915.1047 Ethylene oxide. Note: The requirements applicable to shipyard employment under this...

  15. 29 CFR 1926.1147 - Ethylene oxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Ethylene oxide. 1926.1147 Section 1926.1147 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Ethylene oxide. Note: The requirements applicable to construction work under this section are identical...

  16. 29 CFR 1915.1047 - Ethylene oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Ethylene oxide. 1915.1047 Section 1915.1047 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1047 Ethylene oxide. Note: The requirements applicable to shipyard employment under this...

  17. 29 CFR 1926.1147 - Ethylene oxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false Ethylene oxide. 1926.1147 Section 1926.1147 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Ethylene oxide. Note: The requirements applicable to construction work under this section are identical...

  18. 29 CFR 1915.1047 - Ethylene oxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Ethylene oxide. 1915.1047 Section 1915.1047 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1047 Ethylene oxide. Note: The requirements applicable to shipyard employment under this...

  19. 29 CFR 1926.1147 - Ethylene oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Ethylene oxide. 1926.1147 Section 1926.1147 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Ethylene oxide. Note: The requirements applicable to construction work under this section are identical...

  20. 29 CFR 1926.1147 - Ethylene oxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Ethylene oxide. 1926.1147 Section 1926.1147 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Ethylene oxide. Note: The requirements applicable to construction work under this section are identical...

  1. 29 CFR 1915.1047 - Ethylene oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Ethylene oxide. 1915.1047 Section 1915.1047 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1047 Ethylene oxide. Note: The requirements applicable to shipyard employment under this...

  2. Mortality among workers exposed to ethylene oxide.

    PubMed

    Steenland, K; Stayner, L; Greife, A; Halperin, W; Hayes, R; Hornung, R; Nowlin, S

    1991-05-16

    Ethylene oxide is a sterilant gas that causes leukemia and other cancers in animals. Studies in Sweden have shown an excess of leukemia and stomach cancer in humans exposed to ethylene oxide, but other studies have generally failed to confirm these findings. We conducted a study of mortality in 18,254 U.S. workers exposed to ethylene oxide at 14 plants producing sterilized medical supplies and spices. The subjects averaged 4.9 years of exposure to the gas and 16 years of follow-up. The exposure levels in recent years averaged 4.3 ppm (eight-hour time-weighted adjusted exposure) for sterilizer operators and 2.0 ppm for other workers. The levels in earlier years are likely to have been several times higher. Mortality in this cohort was compared with that in the general U.S. population. Overall there was no significant increase in mortality from any cause in the study cohort. The standardized mortality ratios (SMRs) were 0.97 for leukemia (95 percent confidence interval, 0.52 to 1.67; 13 deaths observed), 1.06 for all hematopoietic cancers (95 percent confidence interval, 0.75 to 1.47; 36 deaths), and 0.94 for stomach cancer (95 percent confidence interval, 0.45 to 1.70; 11 deaths). Analyses according to job category and according to the duration of exposure showed no excess in cancers, as compared with the rate in the general population, but there was a significant trend toward increased mortality with increasing lengths of time since the first exposure for all hematopoietic cancers. The rate of death from hematopoietic cancer (especially non-Hodgkin's lymphoma) was significantly increased among men (SMR, 1.55; 27 deaths). Mortality from leukemia in recent years (1985 through 1987) was significantly increased among men (SMR, 3.45; 5 deaths). For the entire cohort, there was no increase in mortality from hematopoietic cancer. There was a slight but significant increase among men, however. Among men and women combined, there was a trend toward an increased risk of

  3. 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

  4. Microbiological Aspects of Ethylene Oxide Sterilization

    PubMed Central

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

    1970-01-01

    A specially built thermochemical death-rate apparatus is described which can be used to determine the resistance of microorganisms to ethylene oxide under controlled conditions. The apparatus was designed to provide instantaneous exposure of microorganisms to ethylene oxide and to eliminate variables that could result in errors when death kinetic reaction rates are calculated. The apparatus is used to obtain ethylene oxide resistance data which are useful in evaluating and developing sterilizing cycles for materials with known bacterial concentrations, as well as for calculating probability factors on which a given test condition can be expected to provide sterilization. PMID:4984364

  5. Damage of office supply, personal use items, and over-the-counter medical devices after sterilization by ethylene oxide gas, electron beam, and gamma radiation.

    PubMed

    Lucas, Anne D; Merritt, Katharine; Hitchins, Victoria M

    2004-01-01

    After letters containing Bacillus anthracis spores entered the U.S. mail in 2001, a problem emerged regarding how to decontaminate the letters, packages, and personal items in offices that received these letters. The effects of three sterilization methods (i.e. ethylene oxide gas [EO], electron beam [e-beam] radiation, and gamma radiation) were evaluated for a variety of office supply and equipment, personal use items, and over-the-counter medical devices. No single sterilization method was suitable for all items that could be mailed or found in an office. Damage or discoloration was evident for some items by each sterilization method. There were changes in the color of certain items, such as some of the packaging material, some pacifiers, some of the fabrics, and the nylon stockings after e-beam and gamma radiation. Both e-beam and gamma radiation damaged all film samples. Following EO sterilization and normal aeration, there were a number of samples with high (above 250 microg/g) levels of EO and samples with detectable ethylene chlorohydrin levels. The data would suggest that certain items exposed to EO sterilization must be further aerated prior to use, or discarded. Generic descriptions of products (such as plastics) or grouping of items (such as condoms) were not sufficient to predict what is safe in terms of EO residual levels remaining on an item. Successful decontamination of a wide variety of items will require careful selection of different sterilization methods.

  6. 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...

  7. 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...

  8. 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... 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...

  9. 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... 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...

  10. Contamination control by use of ethylene oxide

    NASA Technical Reports Server (NTRS)

    Stroud, R. H.; Lyle, R. G.

    1972-01-01

    The uses of ethylene oxide as a decontaminating agent for planetary quarantine related applications are reported. Aspects discussed include: applications and limitations, chemical and physical properties, germicidal activity, methods of applications, and effects on personnel.

  11. Ethylene oxide sterilization: the way ahead.

    PubMed

    Peacock, R

    1999-01-01

    Despite many predictions about the demise of ethylene oxide as a sterilization method, it continues to be used for increasing volumes of medical devices. This article examines why this has happened and what the future holds.

  12. 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.

  13. 46 CFR 151.50-12 - Ethylene oxide.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Ethylene oxide. 151.50-12 Section 151.50-12 Shipping... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-12 Ethylene oxide. (a)(1) Ethylene... otherwise provided for in paragraph (a)(3) of this section. (2) Ethylene oxide shall be loaded at...

  14. 46 CFR 151.50-12 - Ethylene oxide.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Ethylene oxide. 151.50-12 Section 151.50-12 Shipping... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-12 Ethylene oxide. (a)(1) Ethylene... otherwise provided for in paragraph (a)(3) of this section. (2) Ethylene oxide shall be loaded at...

  15. 46 CFR 151.50-12 - Ethylene oxide.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Ethylene oxide. 151.50-12 Section 151.50-12 Shipping... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-12 Ethylene oxide. (a)(1) Ethylene... otherwise provided for in paragraph (a)(3) of this section. (2) Ethylene oxide shall be loaded at...

  16. 46 CFR 151.50-12 - Ethylene oxide.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Ethylene oxide. 151.50-12 Section 151.50-12 Shipping... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-12 Ethylene oxide. (a)(1) Ethylene... otherwise provided for in paragraph (a)(3) of this section. (2) Ethylene oxide shall be loaded at...

  17. 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....770 Ethylene oxide polymer. The polymer of ethylene oxide may be safely used as a foam stabilizer in fermented malt beverages in accordance with the following conditions. (a) It is the polymer of ethylene...

  18. 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.

  19. 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.

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

    PubMed

    Carlin, D A; Bertolani, S J; Siegel, J B

    2015-02-11

    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.

  1. Highly CO2-Selective Gas Separation Membranes Based on Segmented Copolymers of Poly(Ethylene oxide) Reinforced with Pentiptycene-Containing Polyimide Hard Segments.

    PubMed

    Luo, Shuangjiang; Stevens, Kevin A; Park, Jae Sung; Moon, Joshua D; Liu, Qiang; Freeman, Benny D; Guo, Ruilan

    2016-01-27

    Poly(ethylene oxide) (PEO)-containing polymer membranes are attractive for CO2-related gas separations due to their high selectivity toward CO2. However, the development of PEO-rich membranes is frequently challenged by weak mechanical properties and a high crystallization tendency of PEO that hinders gas transport. Here we report a new series of highly CO2-selective, amorphous PEO-containing segmented copolymers prepared from commercial Jeffamine polyetheramines and pentiptycene-based polyimide. The copolymers are much more mechanically robust than the nonpentiptycene containing counterparts due to the molecular reinforcement mechanism of supramolecular chain threading and interlocking interactions induced by the pentiptycene structures, which also effectively suppresses PEO crystallization leading to a completely amorphous structure even at 60% PEO weight content. Membrane transport properties are sensitively affected by both PEO weight content and PEO chain length. A nonlinear correlation between CO2 permeability with PEO weight content was observed due to the competition between solubility and diffusivity contributions, whereby the copolymers change from being size-selective to solubility-selective when PEO content reaches 40%. CO2 selectivities over H2 and N2 increase monotonically with both PEO content and chain length, indicating strong CO2-philicity of the copolymers. The copolymer film with the longest PEO sequence (PEO2000) and highest PEO weight content (60%) showed a measured CO2 pure gas permeability of 39 Barrer, and ideal CO2/H2 and CO2/N2 selectivities of 4.1 and 46, respectively, at 35 °C and 3 atm, making them attractive for hydrogen purification and carbon capture.

  2. Round-robin evaluation of a solid-phase microextraction-gas chromatographic method for reliable determination of trace level ethylene oxide in sterilized medical devices.

    PubMed

    Harper, Thomas; Cushinotto, Lisa; Blaszko, Nancy; Arinaga, Julie; Davis, Frank; Cummins, Calvin; DiCicco, Michael

    2008-02-01

    Medical devices that are sterilized with ethylene oxide (EtO) retain small quantities of EtO residuals, which may cause negative systemic and local irritating effects, and must be accurately quantified to ensure non-toxicity. The goal of this round-robin study is to investigate the capability of a novel solid-phase microextraction-gas chromatographic (SPME-GC) method for trace-level EtO residuals analysis: three independent laboratories conducted a guided experiment using this SPME-GC method, in assessing method performance, ruggedness and the feasibility of SPME fibers. These were satisfactory across the independent laboratories, at the 0.05-5.00 ppm EtO range. This method was then successfully applied to analyze EtO residuals in several sterilized/aerated medical devices of various polymeric composition, reliably detecting and quantifying the trace levels of EtO residuals present ( approximately 0.05 ppm EtO). SPME is a feasible alternative for quantifying trace-level EtO residuals in sterilized medical devices, thereby lowering the limit of quantification (LOQ) by as much as two to three orders of magnitude over the current GC methodology of direct liquid injection.

  3. How plants sense ethylene gas--the ethylene receptors.

    PubMed

    Lacey, Randy F; Binder, Brad M

    2014-04-01

    Ethylene is a hormone that affects many processes important for plant growth, development, and responses to stresses. The first step in ethylene signal transduction is when ethylene binds to its receptors. Numerous studies have examined how these receptors function. In this review we summarize many of these studies and present our current understanding about how ethylene binds to the receptors. The biochemical output of the receptors is not known but current models predict that when ethylene binds to the receptors, the activity of the associated protein kinase, CTR1 (constitutive triple response1), is reduced. This results in downstream transcriptional changes leading to ethylene responses. We present a model where a copper cofactor is required and the binding of ethylene causes the receptor to pass through a transition state to become non-signaling leading to lower CTR1 activity.

  4. Pure and Modified Co-Poly(amide-12-b-ethylene oxide) Membranes for Gas Separation Studied by Molecular Investigations

    PubMed Central

    De Lorenzo, Luana; Tocci, Elena; Gugliuzza, Annarosa; Drioli, Enrico

    2012-01-01

    This paper deals with a theoretical investigation of gas transport properties in a pure and modified PEBAX block copolymer membrane with N-ethyl-o/p-toluene sulfonamide (KET) as additive molecules. Molecular dynamics simulations using COMPASS force field, Gusev-Suter Transition State Theory (TST) and Monte Carlo methods were used. Bulk models of PEBAX and PEBAX/KET in different copolymer/additive compositions were assembled and analyzed to evaluate gas permeability and morphology to characterize structure-performance relationships. PMID:24958285

  5. 21 CFR 172.808 - Copolymer condensates of ethylene oxide and propylene oxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Copolymer condensates of ethylene oxide and... ethylene oxide and propylene oxide. Copolymer condensates of ethylene oxide and propylene oxide may be... percent aqueous solution. (2) α-Hydro-omega-hydroxy-poly (oxy-ethylene)poly(oxypropylene)-(53-59...

  6. 21 CFR 172.808 - Copolymer condensates of ethylene oxide and propylene oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Copolymer condensates of ethylene oxide and... ethylene oxide and propylene oxide. Copolymer condensates of ethylene oxide and propylene oxide may be... percent aqueous solution. (2) α-Hydro-omega-hydroxy-poly (oxy-ethylene)poly(oxypropylene)-(53-59...

  7. 21 CFR 172.808 - Copolymer condensates of ethylene oxide and propylene oxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Copolymer condensates of ethylene oxide and... ethylene oxide and propylene oxide. Copolymer condensates of ethylene oxide and propylene oxide may be... percent aqueous solution. (2) α-Hydro-omega-hydroxy-poly (oxy-ethylene)poly(oxypropylene)-(53-59...

  8. 21 CFR 172.808 - Copolymer condensates of ethylene oxide and propylene oxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Copolymer condensates of ethylene oxide and... ethylene oxide and propylene oxide. Copolymer condensates of ethylene oxide and propylene oxide may be... percent aqueous solution. (2) α-Hydro-omega-hydroxy-poly (oxy-ethylene)poly(oxypropylene)-(53-59...

  9. The impact of carbon dioxide and exhaust gas recirculation on the oxidative reactivity of soot from ethylene flames and diesel engines

    NASA Astrophysics Data System (ADS)

    Al-Qurashi, Khalid O.

    Restrictive emissions standards to reduce nitrogen oxides (NOx) and particulate matter (PM) emissions from diesel engines necessitate the development of advanced emission control technology. The engine manufacturers in the United States have implemented the exhaust gas recirculation (EGR) and diesel particulate filters (DPF) to meet the stringent emissions limits on NOx and PM, respectively. Although the EGR-DPF system is an effective means to control diesel engine emissions, there are some concerns associated with its implementation. The chief concern with this system is the DPF regenerability, which depends upon several factors, among which are the physicochemical properties of the soot. Despite the plethora of research that has been conducted on DPF regenerability, the impact of EGR on soot reactivity and DPF regenerability is yet to be examined. This work concerns the impact of EGR on the oxidative reactivity of diesel soot. It is part of ongoing research to bridge the gap in establishing a relationship between soot formation conditions, properties, and reactivity. This work is divided into three phases. In the first phase, carbon dioxide (CO2) was added to the intake charge of a single cylinder engine via cylinders of compressed CO2. This approach simulates the cold-particle-free EGR. The results showed that inclusion of CO2 changes the soot properties and yields synergistic effects on the oxidative reactivity of the resulting soot. The second phase of this research was motivated by the findings from the first phase. In this phase, post-flame ethylene soot was produced from a laboratory co-flow laminar diffusion flame to better understand the mechanism by which the CO2 affects soot reactivity. This phase was accomplished by successfully isolating the dilution, thermal, and chemical effects of the CO2. The results showed that all of these effects account for a measurable increase in soot reactivity. Nevertheless, the thermal effect was found to be the most

  10. 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%).

  11. 21 CFR 172.808 - Copolymer condensates of ethylene oxide and propylene oxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Copolymer condensates of ethylene oxide and... CONSUMPTION Multipurpose Additives § 172.808 Copolymer condensates of ethylene oxide and propylene oxide. Copolymer condensates of ethylene oxide and propylene oxide may be safely used in food under the...

  12. On ethylene oxide neurotoxicity: report of two cases of peripheral neuropathy.

    PubMed

    Zampollo, A; Zacchetti, O; Pisati, G

    1984-03-01

    Two cases of clinically and electromyographically proven ethylene oxide neuropathy occurred among 12 workers at the Lecco Hospital Sterilization Center. Cessation of exposure to the gas, which had lasted for two years, was followed by swift remission of the symptoms and complete normalisation of the EMG record at follow-up six months later. The paucity of published data on the subject may well mean that the real risk of ethylene oxide toxicity is being underrated.

  13. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (Final Report)

    EPA Science Inventory

    EPA has finalized its Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide. This assessment addresses the potential carcinogenicity from long-term inhalation exposure to ethylene oxide. Now final, this assessment updates the carcinogenicity information in EPA’s 1985 Hea...

  14. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (Final Report)

    EPA Science Inventory

    EPA has finalized its Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide. This assessment addresses the potential carcinogenicity from long-term inhalation exposure to ethylene oxide. Now final, this assessment updates the carcinogenicity information in EPA’s 1985 Hea...

  15. 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.

  16. Occupational exposure to ethylene oxide and risk of lymphoma.

    PubMed

    Kiran, Sibel; Cocco, Pierluigi; Mannetje, Andrea't; Satta, Giannina; D'Andrea, Ileana; Becker, Nikolaus; de Sanjosé, Silvia; Foretova, Lenka; Staines, Anthony; Kleefeld, Silke; Maynadié, Marc; Nieters, Alexandra; Brennan, Paul; Boffetta, Paolo

    2010-11-01

    Ethylene oxide, a high-volume commodity, is an established human carcinogen, although the relevant epidemiologic evidence is limited. We explored the association between occupational exposure to ethylene oxide and risk of lymphoma in a case-control study, including 2347 lymphoma cases first diagnosed in 1998-2004 and 2463 controls, from 6 European countries. The diagnosis of lymphoma was based on the 2001 World Health Organization Classification of lymphoma. Occupational exposure to ethylene oxide was retrospectively assessed by industrial hygienists and occupational physicians based on detailed self-reported information. We modeled risk of lymphoma with unconditional logistic regression analysis as a function of various exposure measures, adjusting for age, sex, and participating center. Thirty-one cases and 27 controls (1.2% of the total study population) were defined as ever having been exposed to ethylene oxide (odds ratio = 1.3 [95% confidence interval [CI] = 0.7-2.1]). Lymphoma risk showed a 4.3-fold increase associated with medium-high frequency of exposure to ethylene oxide (95% CI = 1.4-13). Among major subtypes, chronic lymphocytic leukemia was consistently associated with ethylene oxide exposure, related in a dose-response manner to probability, frequency, and duration of exposure, as well as to cumulative exposure and (less definitively) with exposure intensity. Our results add to the evidence that ethylene oxide is a human carcinogen.

  17. A coal mine multi-point fiber ethylene gas concentration sensor

    NASA Astrophysics Data System (ADS)

    Wei, Yubin; Chang, Jun; Lian, Jie; Liu, Tongyu

    2015-03-01

    Spontaneous combustion of the coal mine goaf is one of the main disasters in the coal mine. The detection technology based on symbolic gas is the main means to realize the spontaneous combustion prediction of the coal mine goaf, and ethylene gas is an important symbol gas of spontaneous combustion in the coal accelerated oxidation stage. In order to overcome the problem of current coal ethylene detection, the paper presents a mine optical fiber multi-point ethylene concentration sensor based on the tunable diode laser absorption spectroscopy. Based on the experiments and analysis of the near-infrared spectrum of ethylene, the system employed the 1.62 μm (DFB) wavelength fiber coupled distributed feedback laser as the light source. By using the wavelength scanning technique and developing a stable fiber coupled Herriot type long path gas absorption cell, a ppm-level high sensitivity detecting system for the concentration of ethylene gas was realized, which could meet the needs of coal mine fire prevention goaf prediction.

  18. Ethylene Trace-gas Techniques for High-speed Flows

    NASA Technical Reports Server (NTRS)

    Davis, David O.; Reichert, Bruce A.

    1994-01-01

    Three applications of the ethylene trace-gas technique to high-speed flows are described: flow-field tracking, air-to-air mixing, and bleed mass-flow measurement. The technique involves injecting a non-reacting gas (ethylene) into the flow field and measuring the concentration distribution in a downstream plane. From the distributions, information about flow development, mixing, and mass-flow rates can be dtermined. The trace-gas apparatus and special considerations for use in high-speed flow are discussed. A description of each application, including uncertainty estimates is followed by a demonstrative example.

  19. Complete oxidation of ethylene over supported gold nanoparticle catalysts.

    PubMed

    Ahn, Ho-Geun; Choi, Byoung-Min; Lee, Do-Jin

    2006-11-01

    Complete oxidation of ethylene was performed over supported noble metals or transition metals oxide catalysts and on monoliths under atmospheric pressure. Gold nanoparticles on Al2O3 or MxOy(M = Mo, Fe, Mn) were prepared by impregnation, coprecipitation, deposition, and dispersion methods. Nanoparticles prepared by impregnation method were irregular and very large above 25 nm, but those by coprecipitation and deposition method were uniformly nanosized at 4-5 nm. The gold nanoparticle were outstandingly active in catalyzing oxidation of ethylene. The activity order of these catalysts with preparation methods was deposition > coprecipitation > impregnation, and Au/Co3O4 prepared by deposition method showed the best performance in ethylene oxidation. The addition of gold particles to MxOy/Al2O3 catalyst enhanced the ethylene oxidation activity significantly. The main role of the gold nanoparticles apparently was to promote dissociative adsorption of oxygen and to enhance the reoxidation of the catalyst.

  20. Nitric oxide counters ethylene effects on ripening fruits

    PubMed Central

    Manjunatha, Girigowda; Gupta, Kapuganti J.; Lokesh, Veeresh; Mur, Luis AJ; Neelwarne, Bhagyalakshmi

    2012-01-01

    Ethylene plays a key role in promoting fruit ripening, so altering its biosynthesis/signaling could be an important means to delay this process. Nitric oxide (NO)-generated signals are now being shown to regulate ethylene pathways. NO signals have been shown to transcriptionally repress the expression of genes involved in ethylene biosynthesis enzymes and post-translationally modify methionine adenosyl transferase (MAT) activity through S-nitrosylation to reduce the availably of methyl groups required to produce ethylene. Additionally, NO cross-talks with plant hormones and other signal molecules and act to orchestrate the suppression of ethylene effects by modulating enzymes/proteins that are generally triggered by ethylene signaling at post-climacteric stage. Thus, medication of endogenous NO production is suggested as a strategy to postpone the climacteric stage of many tropical fruits. PMID:22499176

  1. Nitric oxide counters ethylene effects on ripening fruits.

    PubMed

    Manjunatha, Girigowda; Gupta, Kapuganti J; Lokesh, Veeresh; Mur, Luis A J; Neelwarne, Bhagyalakshmi

    2012-04-01

    Ethylene plays a key role in promoting fruit ripening, so altering its biosynthesis/signaling could be an important means to delay this process. Nitric oxide (NO)-generated signals are now being shown to regulate ethylene pathways. NO signals have been shown to transcriptionally repress the expression of genes involved in ethylene biosynthesis enzymes and post-translationally modify methionine adenosyl transferase (MAT) activity through S-nitrosylation to reduce the availably of methyl groups required to produce ethylene. Additionally, NO cross-talks with plant hormones and other signal molecules and act to orchestrate the suppression of ethylene effects by modulating enzymes/proteins that are generally triggered by ethylene signaling at post-climacteric stage. Thus, medication of endogenous NO production is suggested as a strategy to postpone the climacteric stage of many tropical fruits.

  2. Ethylene-oxide sterilisation aids speed to market.

    PubMed

    Strain, Peter; Young, William T

    2004-04-01

    Changes in the ethylene-oxide sterilisation process are providing manufacturers with greater speed to market. Developments that are reducing process times are reported here together with study findings for a number of product families.

  3. Workers exposed to ethylene oxide: a follow up study.

    PubMed

    Gardner, M J; Coggon, D; Pannett, B; Harris, E C

    1989-12-01

    A cohort study has been carried out of 2876 men and women with potential exposure to ethylene oxide. Subjects were identified from employment records at four companies that have produced or used ethylene oxide since the 1950s and at eight hospitals which have had ethylene oxide sterilising units since the 1960s. The cohort represents a substantial proportion of the British workforce with a history of occupational exposure to ethylene oxide. Industrial hygiene data were not available before 1977, but since then time weighted average exposures have been less than 5 ppm in almost all jobs and less than 1 ppm in many. Past exposures were probably somewhat higher. In contrast to some previous studies, no clear excess of leukaemia (three deaths observed, 2.09 expected) and no increase in stomach cancer (five deaths observed, 5.95 expected) were found. This discrepancy with earlier reports may be due in part to differences in levels of exposure. Total cancer mortality was similar to that expected from national and local death rates. Some specific cancers showed small excesses but their relevance to ethylene oxide exposure is doubtful. Again, contrary to some earlier reports, no excess of cardiovascular disease was found. This study does not exclude the possibility that ethylene oxide is a human carcinogen but suggests that any risk of cancer from currently permitted occupational exposures is small.

  4. Workers exposed to ethylene oxide: a follow up study.

    PubMed Central

    Gardner, M J; Coggon, D; Pannett, B; Harris, E C

    1989-01-01

    A cohort study has been carried out of 2876 men and women with potential exposure to ethylene oxide. Subjects were identified from employment records at four companies that have produced or used ethylene oxide since the 1950s and at eight hospitals which have had ethylene oxide sterilising units since the 1960s. The cohort represents a substantial proportion of the British workforce with a history of occupational exposure to ethylene oxide. Industrial hygiene data were not available before 1977, but since then time weighted average exposures have been less than 5 ppm in almost all jobs and less than 1 ppm in many. Past exposures were probably somewhat higher. In contrast to some previous studies, no clear excess of leukaemia (three deaths observed, 2.09 expected) and no increase in stomach cancer (five deaths observed, 5.95 expected) were found. This discrepancy with earlier reports may be due in part to differences in levels of exposure. Total cancer mortality was similar to that expected from national and local death rates. Some specific cancers showed small excesses but their relevance to ethylene oxide exposure is doubtful. Again, contrary to some earlier reports, no excess of cardiovascular disease was found. This study does not exclude the possibility that ethylene oxide is a human carcinogen but suggests that any risk of cancer from currently permitted occupational exposures is small. PMID:2611160

  5. Extraction and stability of ethylene oxide residue in medical devices.

    PubMed

    Lucas, Anne D; Stratmeyer, Melvin E

    2008-01-01

    Ethylene oxide (EO) gas is commonly used to sterilize medical devices. A major concern is the amount of residue that may remain on or in the device and be available in the body. Some standards (ASTMF619 and ISO 10993-12) recommend using two different extraction solutions (one polar, one nonpolar), for sample preparation prior to testing medical devices. However, ISO 10993-7 recommends water to process medical devices to determine EO residual levels. To address this, EO residual levels were examined in different extraction solutions. EO residual levels from devices and materials extracted with different solutions were evaluated. Results from this study indicate little difference between extraction solutions of water, cell culture media, and serum (less than 30% difference). Given the increased cost and increased background noise of media or serum over water, using only water to process medical devices and materials for EO residues appears adequate.

  6. In vivo oxidation and surface damage in retrieved ethylene oxide-sterilized total knee arthroplasties.

    PubMed

    MacDonald, Daniel; Hanzlik, Josa; Sharkey, Peter; Parvizi, Javad; Kurtz, Steven M

    2012-07-01

    Gas sterilization (eg, ethylene oxide [EtO] and gas plasma) was introduced for polyethylene to reduce oxidation due to free radicals occurring during radiation sterilization. Recently, oxidation has been observed in polyethylenes with undetectable levels of free radicals, which were expected to be oxidatively stable. It is unclear whether in vivo oxidation will occur in unirradiated inserts sterilized with EtO. We analyzed the oxidation, mechanical behavior, and surface damage mechanisms of tibial inserts of a single design sterilized using EtO. We collected 20 EtO-sterilized tibial inserts at revision surgeries. We assessed oxidative using Fourier transform infrared spectroscopy and mechanical properties using the small punch test. Surface damage was assessed using damage scoring techniques and micro-CT. Oxidation indexes were low and uniform between the regions. The subtle changes did not affect the mechanical properties of the polymer. The dominant surface damage modes included burnishing, abrasion, and third-body wear. There was no evidence of delamination in the retrievals. The retrieved EtO-sterilized UHMWPE retrievals remained stable with respect to both oxidative and mechanical properties for up to 10 years in vivo. We did observe slight measurable amounts of oxidation in the inserts; however, it was far below levels that would be expected to compromise the strength of the polymer. Due to the stable oxidative and mechanical properties, EtO-sterilized tibial components appear to be an effective alternative to gamma-sterilized inserts, at least in short-term implantations.

  7. Ethylene oxide exposure may increase the risk of spontaneous abortion, preterm birth, and postterm birth.

    PubMed

    Rowland, A S; Baird, D D; Shore, D L; Darden, B; Wilcox, A J

    1996-07-01

    Ethylene oxide is a gas used in some dental offices to sterilize equipment. In pregnant laboratory animals, ethylene oxide increases malformations and feral loss. Increased gestation length has also been reported. In humans, two studies have reported increased spontaneous abortions among ethylene oxide-exposed women, but few other data exist. We sent questionnaires to 7,000 dental assistants, age 18-39 years, registered in California in 1987; 4,856 responded (69%). We based our analysis on 1,320 women whose most recent pregnancy was conceived while working full-time. Thirty-two women reported exposure to ethylene oxide; unexposed dental assistants comprised the comparison group. We estimated relative risks of spontaneous abortion and preterm birth using a person-week model. We estimated relative risks of postterm birth (> or = 42 weeks) and a combined adverse outcomes model using logistic regression. Among exposed women, the age-adjusted relative risk of spontaneous abortion was 2.5 [95% confidence interval (CI) = 1.0-6.3], for preterm birth 2.7 (95% CI = 0.8-8.8), and for postterm birth 2.1 (95% CI = 0.7-5.9). The estimated relative risk of any of these adverse outcomes among exposed women was 2.5 (95% CI = 1.0-6.1) after adjusting for age, nitrous oxide, and number of mercury amalgams prepared. These data further implicate ethylene oxide as a possible reproductive toxicant in humans.

  8. Aeration time following ethylene oxide sterilization for reusable rigid sterilization containers: concentration of gaseous ethylene oxide in containers.

    PubMed

    Nakata, S; Umeshita, K; Ueyama, H; Takashina, M; Noguchi, S; Murata, A; Ochi, T

    2000-01-01

    Because ethylene oxide (EO) gas is toxic to humans, restrictions have been imposed on its use for sterilization, specifying allowable levels of residual EO remaining in sterilized apparatus and materials. However, the aeration time that optimizes the removal of the remaining EO when a rigid sterilizing container is used for a vessel had not been identified. Therefore, polyvinyl chloride, which easily adsorbs EO, was placed in rigid sterilizing containers, and aeration was carried out after 1, 8, 12, 17, and 24 hours. After standard EO sterilization, the EO concentrations remaining in the air in the rigid containers were measured. The results indicate that a period of 17 hours of aeration is appropriate when a rigid sterilizing container is used.

  9. [Decontamination of some spices by ethylene oxide. Development of 2-chloroethanol and ethylene glycol during the preservation].

    PubMed

    Chaigneau, M; Muraz, B

    1993-01-01

    After the disinfection by ethylene oxide and storage by ethylene oxide in definite conditions of 16 spices (parsley, chervil, tarragone, chive, thyme, rosemary, coriander, nutmeg, mace, cinnamon, allspices, clove, pepper), the authors observed the fast loss of residual ethylene oxide and ethyleneglycol. On the contrary, the persistence of 2-chloroethanol was followed up for 6 months. They turn their attention to the toxicity of this compound to ensure the protection of customers.

  10. 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.

  11. 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.

  12. Anomalous diffusion of poly(ethylene oxide) in agarose gels.

    PubMed

    Brenner, Tom; Matsukawa, Shingo

    2016-11-01

    We report on the effect of probe size and diffusion time of poly(ethylene) oxide in agarose gels. Time-dependence of the diffusion coefficient, reflecting anomalous diffusion, was observed for poly(ethylene) oxide chains with hydrodynamic radii exceeding about 20nm at an agarose concentration of 2%. The main conclusion is that the pore distribution includes pores that are only several nm across, in agreement with scattering reports in the literature. Interpretation of the diffusion coefficient dependence on the probe size based on a model of entangled rigid rods yielded a rod length of 72nm.

  13. Rotational spectrum of the tetrafluoromethane-ethylene oxide

    NASA Astrophysics Data System (ADS)

    Gou, Qian; Feng, Gang; Evangelisti, Luca; Caminati, Walther

    2017-05-01

    The rotational spectrum of one conformer of the CF4-ethylene oxide complex has been measured by using a pulsed jet Fourier-transform microwave spectrometer. The observed conformer is stabilized by a CF3⋯O halogen bond, with a distance rC⋯O of ∼3.341 Å. No experimental evidence of the internal rotation of CF4 with respect to ethylene oxide has been observed, but it is expected to be almost free (V3 ∼ 14 cm-1 from ab initio calculations).

  14. Identification of ethylene oxide in herbs, spices and other dried vegetables imported into Italy.

    PubMed

    Bononi, Monica; Quaglia, Giancarlo; Tateo, Fernando

    2014-01-01

    Gas chromatography-mass spectrometry was used to analyse ethylene oxide (EO) in 63 samples of dried vegetable materials for food use derived from import commodities and subjected to quality control for three food-transformation industries. EO residues were quantified through the determination of ethylene chlorohydrin (ECH). About 29% of the samples analysed contained more than 0.3 mg kg(-1) of EO. Thus, this specific analytical control limited to 20% of import aromatic matters needs to be increased. This paper demonstrates the importance of this specific control considering the banned use of microbial decontamination EO treatment in the European Union.

  15. Men assigned to ethylene oxide production or other ethylene oxide related chemical manufacturing: a mortality study.

    PubMed

    Greenberg, H L; Ott, M G; Shore, R E

    1990-04-01

    A retrospective cohort study was conducted to examine the mortality experience of 2174 men employed between 1940 and 1978 by a large chemical company and who had been assigned to a chemical production department that used or produced ethylene oxide (EO). Comparisons were made with the general United States population, the regional population, and with a group of 26,965 unexposed men from the same plants. Comparisons with general United States death rates showed fewer deaths than expected in the EO group due to all causes and for total cancers. There was no statistically significant excess of deaths due to any cause. Seven deaths each due to leukaemia and pancreatic cancer were observed with 3.0 and 4.1 deaths expected. Among the subcohort of men who worked where both average and peak exposure levels were probably highest, however, one death due to pancreatic cancer (0.9 expected) and no deaths due to leukaemia were observed. Four of the seven who died from leukaemia and six of the seven who died from pancreatic cancer had been assigned to the chlorohydrin department where the potential for exposure to EO is judged to have been low. The relative risk of death due to each disease was strongly related to duration of assignments to that department. When men who worked in the chlorohydrin department were excluded, there was no evidence for an association of exposure to EO with pancreatic cancer or leukaemia. Together with the failure to show independent EO associations, the chlorohydrin department results suggest that leukaemia and pancreatic cancer may have been associated primarily with production of ethylene chlorohydrin or propylene chlorohydrin, or both. These results emphasise the importance of examining additional concurrent/asynchronous exposures among human populations exposed to EO.

  16. Optimization of a novel headspace-solid-phase microextraction-gas chromatographic method by means of a Doehlert uniform shell design for the analysis of trace level ethylene oxide residuals in sterilized medical devices.

    PubMed

    DiCicco, Michael P; Lang, Bridget; Harper, Thomas I

    2009-06-01

    Medical devices sterilized by ethylene oxide (EtO) retain trace quantities of EtO residuals, which may irritate patients' tissue. Reliably quantifying trace level EtO residuals in small medical devices requires an extremely sensitive analytical method. In this research, a Doehlert uniform shell design was utilized in obtaining a response surface to optimize a novel headspace-solid-phase microextraction-gas chromatographic (HS-SPME-GC) method developed for analyzing trace levels of EtO residuals in sterilized medical devices, by evaluating sterilized, polymer-coated, drug-eluting cardiovascular stents. The effects of four independent experimental variables (HS-SPME desorption time, extraction temperature, GC inlet temperature and extraction time) on GC peak area response of EtO were investigated simultaneously and the most influential experimental variables determined were extraction temperature and GC inlet temperature, with the fitted model showing no evidence of lack-of-fit. The optimized HS-SPME-GC method demonstrated overall good linearity/linear range, accuracy, repeatability, reproducibility, absolute recovery and high sensitivity. This novel method was successfully applied to analysis of trace levels of EtO residuals in sterilized/aerated cardiovascular stents of various lengths and internal diameter, where, upon heating, trace EtO residuals fully volatilized into HS for extraction, thereby nullifying matrix effects. As an alternative, this novel HS-SPME-GC method can offer higher sensitivity compared with conventional headspace analyzer-based sampling.

  17. Adverse health effects of ethylene oxide and occupational exposure limits.

    PubMed

    Sheikh, K

    1984-01-01

    The proposed revision of the US standard for occupational exposure to ethylene oxide has recently been topical and controversial. Most of the recent experimental and epidemiological evidence of health effects, which provoked lowering the permissible exposure limit, appears to be unreliable and insufficient for risk assessment.

  18. 21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ethylene oxide homopolymer and/or....3410 Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive is a...

  19. 21 CFR 872.3450 - Ethylene oxide homopolymer and/or karaya denture adhesive.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ethylene oxide homopolymer and/or karaya denture... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3450 Ethylene oxide homopolymer and/or karaya denture adhesive. (a) Identification. Ethylene oxide homopolymer and/or...

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

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Ethylene oxide adduct of fatty acid... 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. 21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ethylene oxide homopolymer and/or....3410 Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive is a...

  2. 21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ethylene oxide homopolymer and/or....3410 Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive is a...

  3. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Ethylene oxide adduct of fatty acid... 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)...

  4. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Ethylene oxide adduct of fatty acid... 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)...

  5. 21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ethylene oxide homopolymer and/or....3410 Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive is a...

  6. 46 CFR 154.1730 - Ethylene oxide: Loading and off loading.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Ethylene oxide: Loading and off loading. 154.1730... Operating Requirements § 154.1730 Ethylene oxide: Loading and off loading. (a) The master shall ensure that before ethylene oxide is loaded into a cargo tank: (1) The tank is thoroughly clean, dry, and free...

  7. 21 CFR 872.3450 - Ethylene oxide homopolymer and/or karaya denture adhesive.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ethylene oxide homopolymer and/or karaya denture... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3450 Ethylene oxide homopolymer and/or karaya denture adhesive. (a) Identification. Ethylene oxide homopolymer and/or...

  8. 21 CFR 872.3450 - Ethylene oxide homopolymer and/or karaya denture adhesive.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ethylene oxide homopolymer and/or karaya denture... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3450 Ethylene oxide homopolymer and/or karaya denture adhesive. (a) Identification. Ethylene oxide homopolymer and/or...

  9. 46 CFR 154.1730 - Ethylene oxide: Loading and off loading.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Ethylene oxide: Loading and off loading. 154.1730... Operating Requirements § 154.1730 Ethylene oxide: Loading and off loading. (a) The master shall ensure that before ethylene oxide is loaded into a cargo tank: (1) The tank is thoroughly clean, dry, and free...

  10. 21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ethylene oxide homopolymer and/or....3410 Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive is a...

  11. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Ethylene oxide adduct of fatty acid... 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)...

  12. 46 CFR 154.1730 - Ethylene oxide: Loading and off loading.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Ethylene oxide: Loading and off loading. 154.1730... Operating Requirements § 154.1730 Ethylene oxide: Loading and off loading. (a) The master shall ensure that before ethylene oxide is loaded into a cargo tank: (1) The tank is thoroughly clean, dry, and free...

  13. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Ethylene oxide adduct of fatty acid... 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)...

  14. Residual ethylene oxide in medical devices and device material.

    PubMed

    Lucas, Anne D; Merritt, Katharine; Hitchins, Victoria M; Woods, Terry O; McNamee, Scott G; Lyle, Dan B; Brown, Stanley A

    2003-08-15

    Ethylene oxide (EO) gas is commonly used to sterilize medical devices. The amount of residual EO remaining in a device depends partly on the type and size of polymeric material. A major concern is the amount of residue that may be available in the body. With the use of the method described by AAMI for headspace analysis of EO residues, different polymers and medical devices subjected to different numbers of sterilization cycles were examined. Next, the effect of various extraction conditions and extraction solutions on these polymers and medical devices was evaluated. The results showed different polymers desorb EO differently. One polyurethane (PU 75D) had much higher EO residue than a different polyurethane (PU 80A). Repeated extraction of the PU 75D was necessary to quantify total EO residue levels. Different extraction solutions influence the amount and reproducibility of EO detected, whereas multiple resterilizations showed no difference in amount of residual EO. Bioavailability of EO was estimated by extracting the devices and polymers in water. Comparison of total EO residues to EO that was bioavailable showed no difference for some polymers and devices, while others had an almost eightfold difference. Some standard biocompatibility tests were run on extracts and devices, but no significant effects were observed. Copyright 2003 Wiley Periodicals, Inc.

  15. 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.

  16. 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..., ethylene oxide adduct. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  17. 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..., ethylene oxide adduct. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  18. 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..., ethylene oxide adduct. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  19. 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..., ethylene oxide adduct. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  20. 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..., ethylene oxide adduct. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  1. Thermal oxidative degradation of ethylene tetrafluoroethylene copolymer systems

    NASA Astrophysics Data System (ADS)

    Elders, Jonathan Patrick

    Thermo-oxidative degradation of ethylene tetrafluoroethylene (ETFE) was investigated to determine how modifications for use in an electrical wire system affected its thermal stability. Modifications included electron irradiation and subsequent cross-linking during manufacture and contact with a metal surface. Samples with irradiation histories between 0 and 48 MRads were investigated. Degradation of ETFE was enhanced by contact with a metal "conductor" surface: silver - coated copper. Polymer degradation was analyzed by weight loss kinetics (thermogravimetric analysis (TGA)), changes in polymer morphology (differential scanning calorimetry (DSC)), optical microscopy, attenuated total reflectance (ATR) infrared spectroscopy, and gas chromatography - mass spectroscopy (GC/MS). Conductor aging (copper permeation through silver with subsequent oxidation) was investigated using scanning Auger Electron Spectroscopy (AES). Conductor aging is enhanced in the presence of the polymer surface. Interactions between conductor and polymer were analyzed by optical microscopy, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The rate of polymer degradation from 220°C to 280°C was independent of time and extent of degradation, and rate was proportional to irradiation dose. The activation energy for degradation of unirradiated ETFE was 227 kJ/mol and decreased from 150 to 138 kJ/mol for ETFE irradiated to doses between 6 and 48 MRads. Rates of degradation at 300°C to 320°C were dependent on the extent of degradation. Rates of degradation at temperatures between 230°C and 310°C were an order of magnitude larger in the presence of a conductor than in its absence, and activation energies for degradation in the presence of conductor were reduced to 120 kJ/mol. Degradation was modeled as the combination of bulk polymer degradation and catalytic degradation at the polymer-metal interface. ETFE aged at 250°C in the presence or absence of a conductor

  2. 49 CFR 173.323 - Ethylene oxide.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... following: (1) In hermetically sealed glass or metal inner packagings suitably cushioned in an outer package authorized by § 173.201(b). The maximum quantity permitted in any glass inner packaging is 100 g (3.5 ounces..., as authorized for any compressed gas except acetylene. Pressurizing valves and insulation are...

  3. Epidemiological studies on ethylene oxide and cancer: an updating.

    PubMed

    Hogstedt, L C

    1988-01-01

    In 1959, Dr Lars Ehrenberg and a coworker warned the Swedish authorities that ethylene oxide, a common chemical, constituted a potential cancer hazard. Twenty years later, the first epidemiological study and case reports were published indicating an increased cancer risk after occupational exposure to ethylene oxide. An updating of three small Swedish cohorts comprising 709 employees revealed 33 deaths from cancer whereas 20 were expected from national average rates. The excess was due mainly to an increased risk of stomach cancer in one production plant and an excess of blood and lymphatic malignancies in all three cohorts. The results are in accordance with the results of clastogenic, animal and short-term tests and support Professor Ehrenberg's hypothesis, formulated 28 years ago.

  4. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide ...

    EPA Pesticide Factsheets

    EPA has finalized its Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide. This assessment addresses the potential carcinogenicity from long-term inhalation exposure to ethylene oxide. Now final, this assessment updates the carcinogenicity information in EPA’s 1985 Health Assessment Document. EPA’s program and regional offices may use this assessment to inform decisions to protect human health. The Toxicological Review and charge were reviewed internally by EPA and by other federal agencies and White House Offices before public release. Consistent with the May 2009 IRIS assessment development process, all written comments on IRIS assessments submitted by other federal agencies and White House Offices are made publicly available. Accordingly, interagency comments and the interagency science consultation materials provided to other agencies, including interagency review drafts of the IRIS Toxicological Review of Ammonia and the charge to external peer reviewers, are posted on this site.

  5. ABA crosstalk with ethylene and nitric oxide in seed dormancy and germination.

    PubMed

    Arc, Erwann; Sechet, Julien; Corbineau, Françoise; Rajjou, Loïc; Marion-Poll, Annie

    2013-01-01

    Dormancy is an adaptive trait that enables seed germination to coincide with favorable environmental conditions. It has been clearly demonstrated that dormancy is induced by abscisic acid (ABA) during seed development on the mother plant. After seed dispersal, germination is preceded by a decline in ABA in imbibed seeds, which results from ABA catabolism through 8'-hydroxylation. The hormonal balance between ABA and gibberellins (GAs) has been shown to act as an integrator of environmental cues to maintain dormancy or activate germination. The interplay of ABA with other endogenous signals is however less documented. In numerous species, ethylene counteracts ABA signaling pathways and induces germination. In Brassicaceae seeds, ethylene prevents the inhibitory effects of ABA on endosperm cap weakening, thereby facilitating endosperm rupture and radicle emergence. Moreover, enhanced seed dormancy in Arabidopsis ethylene-insensitive mutants results from greater ABA sensitivity. Conversely, ABA limits ethylene action by down-regulating its biosynthesis. Nitric oxide (NO) has been proposed as a common actor in the ABA and ethylene crosstalk in seed. Indeed, convergent evidence indicates that NO is produced rapidly after seed imbibition and promotes germination by inducing the expression of the ABA 8'-hydroxylase gene, CYP707A2, and stimulating ethylene production. The role of NO and other nitrogen-containing compounds, such as nitrate, in seed dormancy breakage and germination stimulation has been reported in several species. This review will describe our current knowledge of ABA crosstalk with ethylene and NO, both volatile compounds that have been shown to counteract ABA action in seeds and to improve dormancy release and germination.

  6. ABA crosstalk with ethylene and nitric oxide in seed dormancy and germination

    PubMed Central

    Arc, Erwann; Sechet, Julien; Corbineau, Françoise; Rajjou, Loïc; Marion-Poll, Annie

    2013-01-01

    Dormancy is an adaptive trait that enables seed germination to coincide with favorable environmental conditions. It has been clearly demonstrated that dormancy is induced by abscisic acid (ABA) during seed development on the mother plant. After seed dispersal, germination is preceded by a decline in ABA in imbibed seeds, which results from ABA catabolism through 8′-hydroxylation. The hormonal balance between ABA and gibberellins (GAs) has been shown to act as an integrator of environmental cues to maintain dormancy or activate germination. The interplay of ABA with other endogenous signals is however less documented. In numerous species, ethylene counteracts ABA signaling pathways and induces germination. In Brassicaceae seeds, ethylene prevents the inhibitory effects of ABA on endosperm cap weakening, thereby facilitating endosperm rupture and radicle emergence. Moreover, enhanced seed dormancy in Arabidopsis ethylene-insensitive mutants results from greater ABA sensitivity. Conversely, ABA limits ethylene action by down-regulating its biosynthesis. Nitric oxide (NO) has been proposed as a common actor in the ABA and ethylene crosstalk in seed. Indeed, convergent evidence indicates that NO is produced rapidly after seed imbibition and promotes germination by inducing the expression of the ABA 8′-hydroxylase gene, CYP707A2, and stimulating ethylene production. The role of NO and other nitrogen-containing compounds, such as nitrate, in seed dormancy breakage and germination stimulation has been reported in several species. This review will describe our current knowledge of ABA crosstalk with ethylene and NO, both volatile compounds that have been shown to counteract ABA action in seeds and to improve dormancy release and germination. PMID:23531630

  7. Performance limitations of polymer electrolytes based on ethylene oxide polymers.

    SciTech Connect

    Buriez, Olivier; Han, Yong Bong; Hou, Jun; Kerr, John B.; Qiao, Jun; Sloop, Steven E.; Tian, Minmin; Wang, Shanger

    1999-10-07

    Studies of polymer electrolyte solutions for lithium-polymer batteries are described. Two different salts, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium trifluoromethanesulfonate (LiTf), were dissolved in a variety of polymers. The structures were all based upon the ethylene oxide unit for lithium ion solvation and both linear and comb-branch polymer architectures have been examined. Conductivity, salt diffusion coefficient and transference number measurements demonstrate the superior transport properties of the LiTFSI salt over LiTf. Data obtained on all of these polymers combined with LiTFSI salts suggest that there is a limit to the conductivity achievable at room temperature, at least for hosts containing ethylene oxide units. The apparent conductivity limit is 5 x 10-5 S/cm at 25 C. Providing that the polymer chain segment containing the ethylene oxide units is at least 5-6 units long there appears to be little influence of the polymer framework to which the solvating groups are attached. To provide adequate separator function, the mechanical properties may be disconnected from the transport properties by selection of an appropriate architecture combined with an adequately long ethylene oxide chain. For both bulk and interfacial transport of the lithium ions, conductivity data alone is insufficient to understand the processes that occur. Lithium ion transference numbers and salt diffusion coefficients also play a major role in the observed behavior and the transport properties of these polymer electrolyte solutions appear to be quite inadequate for ambient temperature performance. At present, this restricts the use of such systems to high temperature applications. Several suggestions are given to overcome these obstacles.

  8. The Far-infrared Rotational Spectrum of Ethylene Oxide

    NASA Astrophysics Data System (ADS)

    Medcraft, Chris; Thompson, Christopher D.; Robertson, Evan G.; Appadoo, Dominique R. T.; McNaughton, Don

    2012-07-01

    High-resolution FTIR spectra of ethylene oxide have been measured in the far-infrared region using synchrotron radiation. A total of 1182 lines between 15 and 73 cm-1 were assigned, with J max = 64, expanding upon previous studies that had recorded spectra up to 12 cm-1, J max = 49. All available data were co-fitted to provide greatly imp- roved rotational constants for the ground vibrational state that are capable of predicting transitions up to 73 cm-1.

  9. Influence of ethylene oxide exposure on the extraction of indomethacin from dimethicone polymeric rods.

    PubMed

    Hurst, P R; Peplow, P V; von Dadelszen, P

    1982-05-01

    Dimethicone polymeric rods were made to contain 0.3, 2.0, or 3.3% by weight of indomethacin. For each different loading of indomethacin, some of the rods were treated with ethylene oxide at 55 degrees for 1 hr, while others were not exposed to the gas. Treated and untreated rods were sliced, placed in ethanol to extract the indomethacin, and the concentrations of indomethacin in the extracts determined by fluorometry and high-performance liquid chromatography (HPLC). After ethylene oxide treatment, the quantity of indomethacin in the extracts was significantly reduced in rods containing 0.3 and 2.0% indomethacin. For the rods containing 3.3% indomethacin, the recovery of the drug from treated rods was not significantly different from those not exposed.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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.

  11. Effect of Moisture on Ethylene Oxide Sterilization1

    PubMed Central

    Gilbert, George L.; Gambill, Vernon M.; Spiner, David R.; Hoffman, Robert K.; Phillips, Charles R.

    1964-01-01

    Bacterial cells dehydrated beyond a critical point no longer react uniformly to ethylene oxide sterilization. The percentage of cells resistant to the lethal effect of ethylene oxide after desiccation is often as small as 0.1 to 0.001%. However, 5% resistant cells were observed with one type of microorganism dried in broth. The presence of organic matter increases the percentage of cells that become resistant to ethylene oxide after dehydration. The phenomenon is produced by exposing cells to a vacuum or a chemically desiccated atmosphere. It is not a permanent change, because the resistant cells rapidly become susceptible if wetted with water. On the other hand, mere exposure to a high relative humidity (RH), i.e., 75 to 98%, after desiccation requires 6 and 4 days, respectively, to overcome this resistance. Moisture studies showed that there is less water in bacterial cells that have been desiccated and then equilibrated to successively high RH values up to 100% RH, than in cells that have not been desiccated, but allowed to dry naturally until equilibrated to the same RH values. Images FIG. 1 PMID:14239581

  12. 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.

  13. Gas purification by nonthermal plasma: a case study of ethylene.

    PubMed

    Aerts, R; Tu, X; Van Gaens, W; Whitehead, J C; Bogaerts, A

    2013-06-18

    The destruction of ethylene in a dielectric barrier discharge plasma is investigated by the combination of kinetic modeling and experiments, as a case study for plasma-based gas purification. The influence of the specific energy deposition on the removal efficiency and the selectivity toward CO and CO2 is studied for different concentrations of ethylene. The model allows the identification of the destruction pathway in dry and humid air. The latter is found to be mainly initiated by metastable N2 molecules, but the further destruction steps are dominated by O atoms and OH radicals. Upon increasing air humidity, the removal efficiency drops by ± 15% (from 85% to 70%), but the selectivity toward CO and CO2 stays more or less constant at 60% and 22%, respectively. Beside CO and CO2, we also identified acetylene, formaldehyde, and water as byproducts of the destruction process, with concentrations of 1606 ppm, 15033 ppm, and 185 ppm in humid air (with 20% RH), respectively. Finally, we investigated the byproducts generated by the humid air discharge itself, which are the greenhouse gases O3, N2O, and the toxic gas NO2.

  14. Plasma polymerization of an ethylene-nitrogen gas mixture

    NASA Technical Reports Server (NTRS)

    Hudis, M.; Wydeven, T.

    1975-01-01

    A procedure has been developed whereby nitrogen can be incorporated into an organic film from an ethylene-nitrogen gas mixture using an internal electrode capacitively coupled radio frequency reactor. The presence of nitrogen has been shown directly by infrared transmittance spectra and electron spectroscopic chemical analysis data, and further indirect evidence was provided by dielectric measurements and by the reverse osmosis properties of the film. Preparation of a nitrogen containing film did not require vapor from an organic nitrogen containing liquid monomer. Some control over the bonding and stoichiometry of the polymer film was provided by the added degree of freedom of the nitrogen partial pressure in the gas mixture. This new parameter strongly affected the dielectric properties of the plasma polymerized film and could affect the reverse osmosis behavior.

  15. Plasma polymerization of an ethylene-nitrogen gas mixture

    NASA Technical Reports Server (NTRS)

    Hudis, M.; Wydeven, T.

    1975-01-01

    A procedure has been developed whereby nitrogen can be incorporated into an organic film from an ethylene-nitrogen gas mixture using an internal electrode capacitively coupled radio frequency reactor. The presence of nitrogen has been shown directly by infrared transmittance spectra and electron spectroscopic chemical analysis data, and further indirect evidence was provided by dielectric measurements and by the reverse osmosis properties of the film. Preparation of a nitrogen containing film did not require vapor from an organic nitrogen containing liquid monomer. Some control over the bonding and stoichiometry of the polymer film was provided by the added degree of freedom of the nitrogen partial pressure in the gas mixture. This new parameter strongly affected the dielectric properties of the plasma polymerized film and could affect the reverse osmosis behavior.

  16. Ethylene oxide sterilization: how hospitals can adapt to the changes.

    PubMed

    1994-12-01

    Ethylene oxide (EtO) gas sterilizers have been used by hospitals for over 40 years to sterilize surgical equipment and supplies that are heat sensitive or that cannot tolerate excessive moisture. However, in recent decades, EtO has been recognized as a potential mutagenic, reproductive, neurologic, and fire and explosion hazard to workers, and one agency has reportedly voted to classify EtO as carcinogenic to humans. Strict regulations concerning EtO exposure have been imposed by the Occupational Safety and Health Administration (OSHA), and the use of EtO, along with other toxic pollutants, is also being monitored by the Environmental Protection Agency (EPA) under the Clean Air Act. In addition, the use of chlorofluorocarbons (CFCs) as EtO diluents has focused attention on the EtO-CFC mixtures used in many sterilizers because CFCs have been linked to destruction of the ozone layer. Concerns about restrictive regulations related to these issues have prompted many hospitals to examine their use of EtO sterilization and propagated the misinformation that EtO sterilization is being phased out. In this article, we address some commonly asked questions regarding the use and regulation of EtO mixtures, as well as alternative sterilization agents and methods; provide two case studies illustrating how hospitals can evaluate various sterilization options; and summarize our conclusions and recommendations for hospitals facing decisions about sterilization techniques. For related topics, also see our Evaluation Update on endoscope reprocessors and our Hazard Report on improperly connected EtO-CFC cylinders to EtO sterilizers in this issue.

  17. Glycolic acid production using ethylene glycol-oxidizing microorganisms.

    PubMed

    Kataoka, M; Sasaki, M; Hidalgo, A R; Nakano, M; Shimizu, S

    2001-10-01

    Screening for microorganisms oxidizing ethylene glycol to glycolic acid was carried out. Among stock cultures, several yeasts and acetic acid bacteria showed high glycolic acid producing activity. Pichia naganishii AKU 4267 formed the highest concentration of glycolic acid, 35.3 g/l, from 10% (v/v) ethylene glycol (molar conversion yield, 26.0%). Among soil isolates, Rhodotorula sp. 3Pr-126, isolated using propylene glycol as a sole carbon source, formed the highest concentration of glycolic acid, 25.1 g/l, from 10% (v/v) ethylene glycol (molar conversion yield, 18.5%). Rhodotorula sp. 3Pr-126 showed higher activity toward 20% (v/v) ethylene glycol than P. naganishii AKU 4267. Optimization of the conditions for glycolic acid production was investigated using P. naganishii AKU 4267 and Rhodotorula sp. 3Pr-126. Under the optimized conditions, P. naganishii AKU 4267 and Rhodotorula sp. 3Pr-126 formed 105 and 110 g/l of glycolic acid (corrected molar conversion yields, 88.0 and 92.2%) during 120 h of reaction, respectively.

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

    PubMed Central

    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

  19. Chromatographic methods for analysis of ethylene oxide in emissions from stationary sources

    SciTech Connect

    Margeson, J.H.; Steger, J.L.; Homolya, J.B. )

    1990-04-01

    Chromatographic methods of analysis with FID detection are investigated for quantitation of ethylene oxide in emissions from production plants and commercial sterilizers. A column with a stationary phase of 3% Carbowax 20M on 80-100 Chromosorb 101 is used to separate ethylene oxide from potential interferents in emissions from production plants. Two columns are found that allow accurate quantitation of ethylene oxide in emissions from commercial sterilizers. Both columns elute ethylene oxide before Freon 12, the diluent in the sterilization process. One column has a stationary phase of 1% SP-1000 on 60-80 Carbopack B and can be used to quantitate ethylene oxide over a wider range of concentrations than the other column, 5% Fluorcol (a fluorinated oil) on 60-80 Carbopack B. Graphitized carbon, the solid support in both of these columns, appears to participate in the ethylene oxide-Freon 12 separation with the SP-1000 column but not with the Fluorcol column.

  20. Epidemiologic support for ethylene oxide as a cancer-causing agent.

    PubMed

    Hogstedt, C; Aringer, L; Gustavsson, A

    1986-03-28

    The mortality and incidence of cancer in three groups of workers with occupational exposure to ethylene oxide have been assessed. Eight cases of leukemia have occurred among 733 ethylene oxide-exposed workers compared with an expected 0.8 cases. Six cases of stomach cancer have been reported compared with 0.65 cases expected. These epidemiologic results provide support for an increased risk of malignancy in individuals with extended and intermittent exposure to low concentrations of ethylene oxide.

  1. 40 CFR 721.10375 - Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide, copolymer...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Hydroxypropyl methacrylate, reaction... Substances § 721.10375 Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide... reporting. (1) The chemical substance identified generically as hydroxypropyl methacrylate,...

  2. 40 CFR 721.10375 - Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide, copolymer...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Hydroxypropyl methacrylate, reaction... Substances § 721.10375 Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide... reporting. (1) The chemical substance identified generically as hydroxypropyl methacrylate,...

  3. 40 CFR 721.10375 - Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide, copolymer...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Hydroxypropyl methacrylate, reaction... Substances § 721.10375 Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide... reporting. (1) The chemical substance identified generically as hydroxypropyl methacrylate,...

  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. Exposure-response analysis of cancer mortality in a cohort of workers exposed to ethylene oxide.

    PubMed

    Stayner, L; Steenland, K; Greife, A; Hornung, R; Hayes, R B; Nowlin, S; Morawetz, J; Ringenburg, V; Elliot, L; Halperin, W

    1993-11-15

    The authors previously reported results from the largest cohort mortality study of ethylene oxide-exposed workers that has been conducted to date. Here they extend their previous work by quantitatively examining the relation between cancer mortality and ethylene oxide exposure. This study included workers from 13 of the 14 geographically distinct facilities that were included in the previous investigation. These facilities began regularly using ethylene oxide to sterilize medical supplies or spices sometime between 1938 and 1969. Workers were followed from first exposure through December 31, 1987. Historical exposures to ethylene oxide were estimated using a regression model. Standard life-table analysis was used to examine cancer mortality in three categories of cumulative exposure to ethylene oxide. The Cox proportional hazards model was also used to examine cumulative and other measures of ethylene oxide exposure as predictors of cancer mortality. In both the life-table analysis and the Cox model, a positive trend was observed in all lymphatic and hematopoietic cancer mortality for cumulative ethylene oxide exposure. This trend was strengthened when ethylene oxide exposures 10 years prior to death were discounted (lagged) and when the analysis was restricted to neoplasms of lymphoid cell origin. Despite limitations discussed in this paper, the authors believe that these findings provide some support for the hypothesis that exposure to ethylene oxide increases the risk of mortality from lymphatic and hematopoietic neoplasms. The authors intend to continue follow-up of this relatively young cohort, which may allow more definitive conclusions to be drawn in the future.

  6. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide ...

    EPA Pesticide Factsheets

    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. EPA seeks external peer review on how the Agency responded to the SAB panel recommendations, the exposure-response modeling of epidemiologic data, including new analyses since the 2007 external peer review, and on the adequacy, transparency, and clarity of the revised draft. The peer review will include an opportunity for the public to address the peer reviewers.

  7. THE FAR-INFRARED ROTATIONAL SPECTRUM OF ETHYLENE OXIDE

    SciTech Connect

    Medcraft, Chris; Thompson, Christopher D.; McNaughton, Don; Robertson, Evan G.; Appadoo, Dominique R. T.

    2012-07-01

    High-resolution FTIR spectra of ethylene oxide have been measured in the far-infrared region using synchrotron radiation. A total of 1182 lines between 15 and 73 cm{sup -1} were assigned, with J{sub max} = 64, expanding upon previous studies that had recorded spectra up to 12 cm{sup -1}, J{sub max} = 49. All available data were co-fitted to provide greatly imp- roved rotational constants for the ground vibrational state that are capable of predicting transitions up to 73 cm{sup -1}.

  8. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide ...

    EPA Pesticide Factsheets

    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. EPA seeks external peer review on how the Agency responded to the SAB panel recommendations, the exposure-response modeling of epidemiologic data, including new analyses since the 2007 external peer review, and on the adequacy, transparency, and clarity of the revised draft. The peer review will include an opportunity for the public to address the peer reviewers.

  9. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide ...

    EPA Pesticide Factsheets

    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. EPA seeks external peer review on how the Agency responded to the SAB panel recommendations, the exposure-response modeling of epidemiologic data, including new analyses since the 2007 external peer review, and on the adequacy, transparency, and clarity of the revised draft. The peer review will include an opportunity for the public to address the peer reviewers.

  10. Ethylene oxide: an overview of toxicologic and epidemiologic research.

    PubMed

    Landrigan, P J; Meinhardt, T J; Gordon, J; Lipscomb, J A; Burg, J R; Mazzuckelli, L F; Lewis, T R; Lemen, R A

    1984-01-01

    Ethylene oxide (EtO) is a reactive epoxide and potent biocide. It is used widely in gas sterilization of hospital equipment. An estimated 75,000 health care workers in the United States have potential exposure. EtO binds covalently to deoxyribonucleic acid (DNA) and has been shown in 13 species to cause point mutations. Apparently, as a consequence of its alkylating ability, EtO exposure can result in chromosomal damage. In monkeys EtO exposure produces increased frequencies of sister chromatid exchanges (SCEs) and chromosomal aberrations. In man, five cytogenetic studies have shown dose-related increased frequencies of either SCE or chromosomal aberrations; in one study SCEs developed after regular exposures lasting less than five minutes per day. EtO is a reproductive toxin. In adult male rats, exposure produces decreased fertility, increased fetal deaths, and heritable chromosomal translocations. In pregnant female rats and rabbits, exposure causes increased fetal losses, and in one study in pregnant mice exposure was associated with increased numbers of malformed fetuses. In male monkeys EtO causes dose-related reductions in sperm count and sperm motility. In pregnant women, one study suggests that brief occupational exposure twice daily in concentrations of 20 ppm or above was associated with increased spontaneous abortions. EtO is carcinogenic to animals. In rats it causes dose-related increases in mononuclear cell leukemias, peritoneal mesotheliomas, and cerebral gliomas. In man, exposure has been associated in two epidemiologic studies with increased leukemias: 3 leukemias observed versus 0.2 expected in one study, and 2 observed versus 0.14 expected in the other; two additional small studies of limited power found no excess leukemias. Quantitative risk assessment indicates that from 634 to 1,093 excess deaths from cancer will occur per 10,000 workers exposed to EtO at 50 ppm over a working lifetime, and that 12 to 23 excess cancer deaths will occur per 10

  11. 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.

  12. Issues in assessing the carcinogenic hazards of ethylene oxide.

    PubMed

    Austin, S G; Sielken, R L

    1988-03-01

    Characterization of the health risks associated with occupational and environmental exposure to ethylene oxide (a gaseous sterilization agent and chemical building block) is made difficult by the limited dose-response information contained in the few published epidemiologic studies available, and the absence of toxicologic data for chronic exposures in species other than the rat. Federal regulatory agencies have relied heavily on conventional quantitative risk assessment techniques in setting revised occupational exposure standards for ethylene oxide. This paper indicates the variability in risk assessment results that can be obtained using the multistage dose-response model and a single animal study depending on the method used to characterize risk, the health endpoint selected, the use of confidence intervals, and the method used to equate animal and human exposure levels. Selection of the most pessimistic options available in each of these four areas is shown to result in a virtually safe dose being characterized as 0.005 ppb, whereas other reasonable assumptions yield a safe dose estimate of 1.3 ppm.

  13. Ethylene oxide sterilization of autologous bone flaps following decompressive craniectomy.

    PubMed

    Missori, P; Polli, F M; Rastelli, E; Baiocchi, P; Artizzu, S; Rocchi, G; Salvati, M; Paolini, S; Delfini, R

    2003-10-01

    In patients undergoing decompressive craniectomy, the bone flap is temporarily preserved either in the subcutaneous tissue of the patient or frozen. However, there are some drawbacks related to these methods. In 16 patients in whom the bone flap was removed for decompressive craniectomy, the bone was firstly washed in hydrogen peroxide and then placed in hermetically-sealed bags and sterilized using ethylene oxide. The bone was repositioned after an average period of 4.3 months. One patient sustained an infection of the surgical wound which required permanent exclusion of the bone flap. In all the others, esthetic and functional results were good after an average follow-up of 20 months. Control CT-scan of the bone flap demonstrated preservation of its structural features with fusion of the bone margins and revitalization of the flap. On MRI a subdural space was again visible. Sterilization of the bone flap with ethylene oxide in patients undergoing decompressive craniectomy avoids some of the drawbacks related to the techniques currently used. The easiness, low cost, good aesthetic and functional results of this procedure make it a valid alternative to other techniques for preservation of autologous bone in decompressive craniectomies.

  14. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide ...

    EPA Pesticide Factsheets

    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) and the expert panel’s final report was made available December 21, 2007. Since that time the Agency implemented the May 2009 IRIS assessment development process in which other federal agencies and the Executive Offices of the President are provided two opportunities to comment on IRIS human health assessments; Interagency Science Consultation (Step 3) prior to public comment/peer review and Interagency Science Discussion (Step 6b) following peer review. In July, 2011, the draft assessment incorporating the SAB recommendations (December 2007) was sent to other federal agencies and Executive Offices of the President as part of Step 6 of the IRIS process. Following the May 2009 process, all written comments submitted by other agencies will be made publicly available. Accordingly, the interagency comments for ethylene oxide and the interagency science discussion materials provided to the other agencies are posted on this site. Note: After further consideration EPA has decided to undertake an additional peer review of the revised draft assessment on how the Agency responded to the SAB panel recommendations (December 2007), the exposure-response modeling of epidemiologic data, including n

  15. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide ...

    EPA Pesticide Factsheets

    In December 2016, EPA finalized its Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide. EPA’s evaluation was reviewed internally by EPA and by other federal agencies and White House Offices in October 2016, before public release. Consistent with the May 2009 IRIS assessment development process, all written comments on IRIS assessments submitted by other federal agencies and White House Offices are made publicly available. Accordingly, interagency comments and the interagency science discussion materials provided to other agencies, including interagency review drafts of the EPA’s Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide, are posted on this site. Note: No major science comments were received on the Interagency Science Discussion Draft. The Toxicological Review and charge were reviewed internally by EPA and by other federal agencies and White House Offices before public release. Consistent with the May 2009 IRIS assessment development process, all written comments on IRIS assessments submitted by other federal agencies and White House Offices are made publicly available. Accordingly, interagency comments and the interagency science consultation materials provided to other agencies, including interagency review drafts of the IRIS Toxicological Review of Ammonia and the charge to external peer reviewers, are posted on this site.

  16. Ethylene oxide in blood of ethylene-exposed B6C3F1 mice, Fischer 344 rats, and humans.

    PubMed

    Filser, Johannes Georg; Kessler, Winfried; Artati, Anna; Erbach, Eva; Faller, Thomas; Kreuzer, Paul Erich; Li, Qiang; Lichtmannegger, Josef; Numtip, Wanwiwa; Klein, Dominik; Pütz, Christian; Semder, Brigitte; Csanády, György András

    2013-12-01

    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.

  17. 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

  18. Ethylene directly inhibits foliar gas exchange in Glycine max

    SciTech Connect

    Gunderson, C.A.; Taylor, G.E. Jr. )

    1991-01-01

    Gas exchange of individual attached leaves of soybean, Glycine max (L,) Merr cv Davis, was monitored during exposure to exogenous ethylene (C{sub 2}H{sub 4}) to test the hypothesis that the effects of C{sub 2}H{sub 4} on net photosynthesis (P{sub n}) and stomatal conductance to H{sub 2}O{sub 4} vapor (g{sub s}) are direct and not mediated by changes in leaf orientation to light. Leaflets were held perpendicular to incident light in a temperature-controlled cuvette throughout a 5.5 hour exposure to 10 microliters per liter C{sub 2}H{sub 4}. Declines in both P{sub N} and g{sub s} were evident within 2 hours and became more pronounced throughout the exposure period. In C{sub 2}H{sub 4} treated plants, P{sub N} and g{sub s} decreased to 80 and 62%, respectively, of the rates in control plants. Because epinastic movement of the leaflets was prohibited by the cuvette, the observed declines in P{sub N} and g{sub s} were a direct effect of C{sub 2}H{sub 4} rather than the result of reduced light interception caused by changing leaf angle.

  19. Poly(ethylene oxide)-poly(butylene oxide)-poly(ethylene oxide)-templated synthesis of mesoporous alumina: effect of triblock copolymer and acid concentration.

    PubMed

    Materna, Kelly L; Grant, Stacy M; Jaroniec, Mietek

    2012-07-25

    Mesoporous alumina was synthesized via a one-pot self-assembly of aluminum isopropoxide and poly(ethylene oxide)-poly(butylene oxide)-poly(ethylene oxide) triblock copolymer in an acidic ethanol solution. The effects of the polymer concentration and nitric acid concentration, independently, on the adsorption properties (such as surface area, pore volume, microporosity, mesoporosity, and pore width) were studied. An increase in the specific surface area and the pore volume was seen for the samples containing a polymer/aluminum isopropoxide wt. ratio up to 0.71 and a polymer/acid wt ratio of 0.88. Titania isopropoxide was also added to the synthesis to illustrate the extension of this approach to alumina-based mixed metal oxides.

  20. Risk-based maintenance of ethylene oxide production facilities.

    PubMed

    Khan, Faisal I; Haddara, Mahmoud R

    2004-05-20

    This paper discusses a methodology for the design of an optimum inspection and maintenance program. The methodology, called risk-based maintenance (RBM) is based on integrating a reliability approach and a risk assessment strategy to obtain an optimum maintenance schedule. First, the likely equipment failure scenarios are formulated. Out of many likely failure scenarios, the ones, which are most probable, are subjected to a detailed study. Detailed consequence analysis is done for the selected scenarios. Subsequently, these failure scenarios are subjected to a fault tree analysis to determine their probabilities. Finally, risk is computed by combining the results of the consequence and the probability analyses. The calculated risk is compared against known acceptable criteria. The frequencies of the maintenance tasks are obtained by minimizing the estimated risk. A case study involving an ethylene oxide production facility is presented. Out of the five most hazardous units considered, the pipeline used for the transportation of the ethylene is found to have the highest risk. Using available failure data and a lognormal reliability distribution function human health risk factors are calculated. Both societal risk factors and individual risk factors exceeded the acceptable risk criteria. To determine an optimal maintenance interval, a reverse fault tree analysis was used. The maintenance interval was determined such that the original high risk is brought down to an acceptable level. A sensitivity analysis is also undertaken to study the impact of changing the distribution of the reliability model as well as the error in the distribution parameters on the maintenance interval.

  1. Microwave desorption: a combined sterilizer/aerator for the accelerated elimination of ethylene oxide residues from sterilized supplies.

    PubMed

    Samuel, A H; Matthews, I P; Gibson, C

    1988-02-01

    Ethylene oxide gas is widely used in medical and related facilities for low-temperature sterilization of surgical devices. Evidence of its toxicity and, in particular, its mutagenicity and carcinogenicity provide sufficient reasons for caution in its use and for minimizing exposure. Little advancement has been made in the removal of ethylene oxide residuals from plastics into which the gas is heavily absorbed during sterilization, despite the fact that the gas has been used for 20 years or more. This article describes a novel process (PCT Application/GB85/00509) in which microwave irradiation of ethylene oxide-sterilized materials is utilized to enhance the rate at which the gas is desorbed. The experimental apparatus is described, and an explanation of the effect of microwaves on the energy of activation for diffusion is given. Data are presented in support of the authors' claim of a 400% improvement in the efficiency of the new process over conventional aeration procedures. The advantages and economy of an integrated sterilizer/microwave-enhanced desorber are discussed in the context of the implications that arise from the current regulatory debate.

  2. Generation of ethylene tracer by noncatalytic pyrolysis of natural gas at elevated pressure

    USGS Publications Warehouse

    Lu, Y.; Chen, S.; Rostam-Abadi, M.; Ruch, R.; Coleman, D.; Benson, L.J.

    2005-01-01

    There is a critical need within the pipeline gas industry for an inexpensive and reliable technology to generate an identification tag or tracer that can be added to pipeline gas to identify gas that may escape and improve the deliverability and management of gas in underground storage fields. Ethylene is an ideal tracer, because it does not exist naturally in the pipeline gas, and because its physical properties are similar to the pipeline gas components. A pyrolysis process, known as the Tragen process, has been developed to continuously convert the ???2%-4% ethane component present in pipeline gas into ethylene at common pipeline pressures of 800 psi. In our studies of the Tragen process, pyrolysis without steam addition achieved a maximum ethylene yield of 28%-35% at a temperature range of 700-775 ??C, corresponding to an ethylene concentration of 4600-5800 ppm in the product gas. Coke deposition was determined to occur at a significant rate in the pyrolysis reactor without steam addition. The ?? 13C isotopic analysis of gas components showed a ?? 13C value of ethylene similar to ethane in the pipeline gas, indicating that most of the ethylene was generated from decomposition of the ethane in the raw gas. However, ?? 13C isotopic analysis of the deposited coke showed that coke was primarily produced from methane, rather than from ethane or other heavier hydrocarbons. No coke deposition was observed with the addition of steam at concentrations of > 20% by volume. The dilution with steam also improved the ethylene yield. ?? 2005 American Chemical Society.

  3. Carcinogenicity and genotoxicity of ethylene oxide: new aspects and recent advances.

    PubMed

    Thier, R; Bolt, H M

    2000-09-01

    Long-term inhalation studies in rodents have presented unequivocal evidence of experimental carcinogenicity of ethylene oxide, based on the formation of malignant tumors at multiple sites. However, despite a considerable body of epidemiological data only limited evidence has been obtained of its carcinogenicity in humans. Ethylene oxide is not only an important exogenous toxicant, but it is also formed from ethylene as a biological precursor. Ethylene is a normal body constituent; its endogenous formation is evidenced by exhalation in rats and in humans. Consequently, ethylene oxide must also be regarded as a physiological compound. The most abundant DNA adduct of ethylene oxide is 7-(2-hydroxyethyl)guanine (HOEtG). Open questions are the nature and role of tissue-specific factors in ethylene oxide carcinogenesis and the physiological and quantitative role of DNA repair mechanisms. The detection of remarkable individual differences in the susceptibility of humans has promoted research into genetic factors that influence the metabolism of ethylene oxide. With this background it appears that current PBPK models for trans-species extrapolation of ethylene oxide toxicity need to be refined further. For a cancer risk assessment at low levels of DNA damage, exposure-related adducts must be discussed in relation to background DNA damage as well as to inter- and intraindividual variability. In rats, subacute ethylene oxide exposures on the order of 1 ppm (1.83 mg/m3) cause DNA adduct levels (HOEtG) of the same magnitude as produced by endogenous ethylene oxide. Based on very recent studies the endogenous background levels of HOEtG in DNA of humans are comparable to those that are produced in rodents by repetitive exogenous ethylene oxide exposures of about 10 ppm (18.3 mg/m3). Experimentally, ethylene oxide has revealed only weak mutagenic effects in vivo, which are confined to higher doses. It has been concluded that long-term human occupational exposure to low airborne

  4. The effect of ethylene exposure on ethylene oxide in blood and on hepatic cytochrome p450 in Fischer rats.

    PubMed

    Fennell, Timothy R; Snyder, Rodney W; Parkinson, Carl; Murphy, John; James, R Arden

    2004-09-01

    Ethylene (74-85-1) is an important petrochemical and is produced endogenously. It is metabolized to ethylene oxide (EO) by cytochrome P450. We studied the inhibition of cytochrome P450 activity during exposure to ethylene, and verified that this inhibition was reflected in the concentration of EO in the blood. Male F344 rats were exposed to 1000, 600, and 300 ppm ethylene by nose-only inhalation for up to 6 h. Blood samples were obtained during exposure. On exposure to 600 ppm ethylene, blood EO concentration increased during the first hour of exposure and then decreased to approximately half of the peak blood concentration. A less pronounced decrease was observed at 300 ppm, and at 1000 ppm little change was observed between 10 min and 6 h of exposure. For the analysis of cytochrome P450 and isozyme-specific substrate activities, groups of four male F344 rats were removed for the collection of liver at various times after exposure to 300, 600, or 1000 ppm ethylene. At all concentrations, liver microsomal cytochrome P450 decreased during exposure. Of the various monooxygenase activities measured, 4-nitrophenol hydroxylase was the one most consistently altered, with maximal inhibition (approximately 50%) at 2 h of exposure to 1000 ppm ethylene, 4 h at 600 ppm, and 6 h at 300 ppm. Activity recovered to control levels by 6 h after exposure. Cytochrome P450 2E1 appears to be the major isoform of cytochrome P450 inhibited by exposure to ethylene, and this may explain in part the observed alteration in EO blood kinetics.

  5. Plasticized-starch/poly(ethylene oxide) blends prepared by extrusion.

    PubMed

    Yu, Fang; Prashantha, Kalappa; Soulestin, Jeremie; Lacrampe, Marie-France; Krawczak, Patricia

    2013-01-02

    Blends based on plasticized-wheat starch (as matrix or rich phase) and poly(ethylene oxide) (PEO) (as dispersed phase) were prepared by melt processing in a twin-screw extruder. The extrusion of the plasticized-starch is significantly facilitated by blending with PEO. Plasticized-starch and PEO are immiscible in the range of the investigated blend ratios (90/10-50/50). The phase inversion takes place when the PEO content is 50 wt.% in the blend. Both the thermal stability and the tensile properties of plasticized-starch are improved by blending with PEO. Also, a synergistic effect between plasticized-starch and PEO is noticed at 25-40 wt.% PEO content in the blend, the Young's modulus of the materials obtained being the highest and higher than both neat polymer components at those blending ratios. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Study of positive and negative plasma catalytic oxidation of ethylene.

    PubMed

    Van Wesenbeeck, K; Hauchecorne, B; Lenaerts, S

    2016-10-06

    The effect of introducing a photocatalytically active coating inside a plasma unit is investigated. This technique combines the advantages of high product selectivity from catalysis and the fast start-up from plasma technology. In this study, a preselected TiO2 coating is applied on the collector electrode of a DC corona discharge unit as non-thermal plasma reactor, in order to study the oxidation of ethylene. For both positive and negative polarities an enhanced mineralization is observed while the formation of by-products drastically decreases. The plasma catalytic unit gave the best results when using negative polarity at a voltage of 15 kV. This shows the potential of plasma catalysis as indoor air purification technology.

  7. Evaluation of the Carcinogenicity of Ethylene Oxide (2006 ...

    EPA Pesticide Factsheets

    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. EPA is announcing a 30-day public comment period for this document. The release of this draft document is solely for the purpose of seeking public comment and for review by the EPA Science Advisory Board (SAB) via a meeting to be held later in 2006. The time and place of the SAB meeting will be announced in a separate Federal Register notice. This document has not been formally disseminated by EPA and does not represent, and should not be construed to represent, any Agency policy or determination. EPA will consider any public comments submitted in accordance with the requirements specified in the Notice of Public Comment Period when revising this draft document.

  8. Ethylene oxide sterilization of medical devices: a review.

    PubMed

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

    2007-11-01

    Ethylene oxide (EO) is a well-known sterilizing agent. However, only recently has its use significantly emerged, based on its range of applications in the field of new medical device development and sterilization. This paper describes the progress in terms of EO sterilization and concludes that it remains a promising field to explore and develop. The EO action mechanism and toxicity are analyzed, and a critical analysis is made on how it is possible to use EO sterilization for medical devices advantageously, with emphasis on cycle design and validation. One huge challenge is related with the development of mathematical models to integrate lethality to allow a continuous increase of process flexibility, without compromising its safety. The scientific community should also focus on other important issues, such as EO diffusion in different substrates, taking into account different environmental conditions both for sterilization and aeration.

  9. Evaluation of the Carcinogenicity of Ethylene Oxide (2006 ...

    EPA Pesticide Factsheets

    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. EPA is announcing a 30-day public comment period for this document. The release of this draft document is solely for the purpose of seeking public comment and for review by the EPA Science Advisory Board (SAB) via a meeting to be held later in 2006. The time and place of the SAB meeting will be announced in a separate Federal Register notice. This document has not been formally disseminated by EPA and does not represent, and should not be construed to represent, any Agency policy or determination. EPA will consider any public comments submitted in accordance with the requirements specified in the Notice of Public Comment Period when revising this draft document.

  10. Unusual behavior of poly(ethylene-oxide) in aqueous mixtures.

    SciTech Connect

    Lal, J.; Hakem, I. F.; IPNS

    2004-10-01

    The model system of poly(ethylene-oxide) or PEO, where the changing hydrogen-bond connectivity of the water has large effect on the conformation of the polymer chain, in mixtures of water and acetonitrile, is experimentally studied. The results show the existence of a threshold water content in the system at which the 3d connectivity of the water network begins. Unusual expansion of the polymer chain, an effect larger than that observed in either of the pure solvents, is seen. Upon addition of small amounts of a monovalent salt, binding of ion to polymer takes place in pure acetonitrile solutions. Salt ions begin to co-ordinate with water molecules at the same solvent ratio as the threshold for water network formation. Ions now no longer complex to PEO; instead, hydrogen bonding of water to the polymer strongly dictates conformation in this regime.

  11. [The role of nitric oxide in ethylene-induced stomatal closure in Vicia faba L].

    PubMed

    Li, Jie; Qiu, Li-Yan; Zhao, Fang-Gui; Hou, Li-Xia; Liu, Xin

    2007-08-01

    The effects of nitric oxide (NO) and ethylene on Vicia faba L. stomatal movement were studied. The results showed that NO donor SNP (sodium nitroprusside) 10 micromol/L and ethylene 0.04% could induce stomatal closure distinctly and they could promote stomatal closure when treated together. When treated with AVG (an inhibitor of ethylene synthesis), c-PTIO (a specific scavenger of NO) and NaN(3) (an inhibitor of NR), the effects of NO- and ethylene-induced stomatal closure were inhibited but the inhibitor of nitric oxide synthase (NOS) had little effect. We presumed that there was coordinative effect between NO and ethylene in regulation of stomatal closure; ethylene could induce stomatal closure by regulating the production of nitrate reductase (NR)-dependent NO.

  12. Ethylene adsorption and oxidation on Pt( h k l) in acidic media

    NASA Astrophysics Data System (ADS)

    Berná, Antonio; Kuzume, Akiyoshi; Herrero, Enrique; Feliu, Juan M.

    Ethylene adsorption and oxidation on platinum electrodes have been investigated in acidic solution by means of cyclic voltammetry and in situ infrared spectroscopy. Ethylene oxidation is a surface structure-sensitive reaction being Pt(1 1 1) the only active electrode surface at potentials below surface oxidation. In situ infrared reflection absorption spectroscopy (IRRAS) allows to identify the products formed during the adsorption and oxidation of ethylene. Vinylidene species were detected as oxidized adsorbates coming from ethylene and the only oxygen-containing species observed were on-top adsorbed CO and dissolved CO 2 that is the final oxidation product. A potential dependent equilibrium for transformation between two different adsorption configurations of adsorbed vinylidene, μ 3-η 2-C dbnd CH 2 and μ-C dbnd CH 2, has been observed.

  13. Ethylene Epoxidation with Nitrous Oxide over Fe-BTC Metal-Organic Frameworks: A DFT Study.

    PubMed

    Maihom, Thana; Choomwattana, Saowapak; Wannakao, Sippakorn; Probst, Michael; Limtrakul, Jumras

    2016-11-04

    The epoxidation of ethylene with N2 O over the metal-organic framework Fe-BTC (BTC=1,3,5-benzentricarboxylate) is investigated by means of density functional calculations. Two reaction paths for the production of ethylene oxide or acetaldehyde are systematically considered in order to assess the efficiency of Fe-BTC for the selective formation of ethylene oxide. The reaction starts with the decomposition of N2 O to form an active surface oxygen atom on the Fe site of Fe-BTC, which subsequently reacts with an ethylene molecule to form an ethyleneoxy intermediate. This intermediate can then be selectively transformed either by 1,2-hydride shift into the undesired product acetaldehyde or into the desired product ethylene oxide by way of ring closure of the intermediate. The production of ethylene oxide requires an activation energy of 5.1 kcal mol(-1) , which is only about one-third of the activation energy of acetaldehyde formation (14.3 kcal mol(-1) ). The predicted reaction rate constants for the formation of ethylene oxide in the relevant temperature range are approximately 2-4 orders of magnitude higher than those for acetaldehyde. Altogether, the results suggest that Fe-BTC is a good candidate catalyst for the epoxidation of ethylene by molecular N2 O. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. 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.

  15. Occupational exposure to ethylene oxide during pregnancy and association with adverse reproductive outcomes.

    PubMed

    Gresie-Brusin, Daniela F; Kielkowski, Danuta; Baker, Abednego; Channa, Kalavati; Rees, David

    2007-07-01

    To investigate the association between exposure to ethylene oxide during pregnancy and adverse reproductive outcomes. Singleton pregnancies were analysed that: (1) had occurred in women working at the time of the study (2004) in hospital sterilising units using ethylene oxide in Gauteng province, South Africa; (2) was the last recognised pregnancy of these women after the 1 January 1992; and (3) this last recorded pregnancy had occurred while the mother was employed. An adverse reproductive outcome was defined as the occurrence of a spontaneous abortion, still birth or pregnancy loss (combined abortion + still birth). Information on the evolution and outcome of the pregnancy was gathered from the mother using a questionnaire. Information on exposure to ethylene oxide during pregnancy was obtained from three sources, namely walk-through surveys, questionnaire-collected data and measurements of the levels of ethylene oxide in sterilising units at the time of the study (personal and static sampling). The study enrolled 69% of the hospitals in Gauteng using ethylene oxide to sterilise medical equipment. The participation rate for women employed in these sterilising units was 97%, and the study population consisted of 98 singleton pregnancies. Measurements of ethylene oxide showed that operators of sterilisers were still potentially over-exposed. There was a significantly increased risk of spontaneous abortion (POR = 20.8, 95% CI = 2.1-199) and pregnancy loss (POR = 8.6, 95% CI = 1.8-43.7) for pregnancies highly exposed to ethylene oxide compared to low exposed pregnancies. No associations were found between exposure to ethylene oxide and stillbirth. An increased risk of spontaneous abortion and pregnancy loss was found to be associated with exposure to ethylene oxide during pregnancy.

  16. Health-hazard evaluation report HETA 86-277-1750, Project Orbis, Inc. , New York, New York. [Ethylene oxide et al

    SciTech Connect

    Boiano, J.M.

    1986-11-01

    In response to a request from the nurse administrator of Project Orbis, Inc., New York, New York, exposures to anesthetics and ethylene oxide were evaluated aboard the aircraft used as a teaching eye hospital. Each mission involved about 20 staff members. Anesthetics included nitrous oxide, halothane, and isoflurane. Ethylene oxide was used for equipment sterilization. Breathing-zone and general air samples were collected, and analytical methods included gas chromatography, spectrophotometry, and adsorbent-based dosimetry. Recovery-room nurses were overexposed to nitrous oxide (up to 79ppm) and isoflurane (0.96ppm) from patients. The author concludes that anesthetic exposures are excessive, and ethylene oxide exposure is a potential risk. Recommendations include engineering controls to limit anesthetic exposure, and good sterilization work practices.

  17. A standardized monitor for the control of ethylene oxide sterilization cycles.

    PubMed Central

    Dadd, A. H.; Stewart, C. M.; Town, M. M.

    1983-01-01

    The resistance of spores of B. subtilis var. niger produced in liquid synthetic medium and exposed to ethylene oxide on a nylon surface, has been shown to the almost identical to that for spores produced on a traditional solidified complex medium with exposure to the sterilant on aluminium foil. The use of short lengths of nylon tube as carriers allowed easy production and handling, with self-protection of the spore-bearing surface. Addition of a dye provided visual evidence of inoculation without affecting resistance to ethylene oxide. Such a monitor is suitable for use as a standardized biological challenge in routine ethylene oxide sterilization cycles. PMID:6411808

  18. Catalysis by Nanostructures: Methane, Ethylene Oxide, and Propylene Oxide Synthesis on Ag, Cu or Au Nanoclusters

    DTIC Science & Technology

    2008-02-07

    GRANT NUMBER Propylene Oxide Synthesis on Ag , Cu or Au nanoclusters F49620-01-1-0459 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Horia...Nanostructures: Methane, Ethylene Oxide, and Propylene Oxide Synthesis on Ag , Cu or Au nanoclusters, F49620-01-1-0459 Final Performance Report (for the period 07...andthe mobility of Ag clusters and Au clusters on TiO 2(1 10) have been published " . We found that Au atoms are very mobile and form large clusters at

  19. Effect of re-sterilization of surgical sutures by ethylene oxide.

    PubMed

    Nagaraja, Prem Anand; Shetty, Devi

    2007-01-01

    Surgical suture packs are opened (and external packaging removed) on the operating table prior to surgery. Some of these suture packs may not be used in the surgery for reasons of inappropriateness or change in the surgical technique or following accidental contact with a non-sterile surface. These unused sutures with their foil packs still unopened are sometimes re-sterilized using ethylene oxide to allow for reuse. This re-sterilization of unopened suture packs can be contentious, due to legislation and health regulations in developed countries. The purpose of the present paper was to measure the effect of such repeated gas sterilization on sutures. The knot tensile strength was measured for new sterile sutures and ethylene oxide re-sterilized sutures. The tests were conducted on two available brands of sutures, including both absorbable and non-absorbable synthetic sutures. No statistically significant difference was observed in the tensile strengths between the two sets of sutures, before and after re-sterilization. Some foil packs showed slight crimping after re-sterilization, but remained intact. No humidity was observed inside the foil packs. Re-sterilization of unused suture foil packs can be carried out without loss of tensile strength.

  20. Increase in early polyethylene wear after sterilization with ethylene oxide: radiostereometric analyses of 201 total hips.

    PubMed

    Digas, Georgios; Thanner, Jonas; Nivbrant, Bo; Röhrl, Stephan; Ström, Håkan; Kärrholm, Johan

    2003-10-01

    We evaluated polyethylene wear by measuring femoral head penetration in 201 THA (median age 62 (31-81) years, 117 women) extracted from 5 randomized studies aimed to assess various fixation principles. There were 30 cemented all-polyethylene Lubinus cups sterilized by gamma irradiation in a reduced oxygen environment, 65 porous-coated Trilogy cups with liners gamma-sterilized in inert gas. Moreover, 37 cemented cups were sterilized with ethylene oxide (Reflection all-poly) and 69 porous-coated cups had liners sterilized in ethylene oxide (Reflection). 28 mm femoral heads were used in all cups. The patients were followed with repeated radiostereometric measurements (RSA) up to 2 years. The activity level of the patients was evaluated by a questionnaire. After 2 years, cups with polyethylene sterilized in EtO had almost twice the proximal and 3D penetration rates, as compared with gamma-sterilized polyethylene. The penetration did not differ between the gamma-irradiated designs. Using stepwise linear regression analysis, we found that the type of sterilization, age and weight were the most important predictors and that they determined the direction of the proximal penetration rate. Activity score, male gender and proximal migration of the cup had little effect. The accelerated wear observed with the EtO-sterilized polyethylene causes concerns about long-term problems and especially in younger patients.

  1. Microbiological Load of Ethylene Oxide Sterilized Medical Devices and its Elimination by Cobalt 60 Source.

    PubMed

    Bashir, Rasheeda; Afroze, Bakht; Zulfiqar, Hafiza Fizza; Saleem, Resham; Altaf, Imran; Saleem, Faiza; Aslam, Farheen; Naz, Shagufta

    2016-06-01

    To determine the residing microbial flora of ethylene oxide (EtO) sterilized medical devices and optimization of safe dose of gamma radiation (Cobalt 60 source) for the complete elimination of microbial load. Experimental study. Department of Biotechnology, Lahore College for Women University, Lahore, Pakistan from September 2014 to June 2015. Thirty-six samples of EtO sterilized medical devices of same batch of three different companies were collected for this study. Isolation and enumeration of microbes were done by using different selective and differential media. Gram staining and biochemically characterization by API 20 (Bio Merieux, France) kit was done for identification of the microorganisms. The medical devices having high microbial load were sent to Pakistan Radiation Services (PARAS) for gamma irradiations at 3 different selected doses (20 KGy, 25 KGy, and 30 KGy). Different types of Gram positive bacteria (Staphylococcus epidermidis, Staphylococcus aureus andBacillus subtilis) were isolated from the EtO sterilized samples. Gram negative bacteria and fungi were not detected on these medical devices. Gamma irradiations results showed that 30 KGy was optimized dose for complete elimination of microbial flora on endotracheal, Nelaton, and tracheostomy tubes. Gamma radiations (Co 60 source) effectively decontaminate the microbial flora on the equipment previously sterilized by the ethylene oxide gas; and 30 KGy is the optimized dose for all these medical devices.

  2. N-heterocyclic carbene-induced zwitterionic ring-opening polymerization of ethylene oxide and direct synthesis of alpha,omega-difunctionalized poly(ethylene oxide)s and poly(ethylene oxide)-b-poly(epsilon-caprolactone) block copolymers.

    PubMed

    Raynaud, Jean; Absalon, Christelle; Gnanou, Yves; Taton, Daniel

    2009-03-11

    An N-heterocyclic carbene (NHC), namely, 1,3-bis-(diisopropyl)imidazol-2-ylidene (1), was demonstrated to bring about the metal-free ring-opening polymerization of ethylene oxide at 50 degrees C in dimethyl sulfoxide, in absence of any other reagents. Poly(ethylene oxide) (PEO) of polydispersities <1.2 and molar masses perfectly matching the [monomer]/[(1)] ratio could thus be obtained in quantitative yields, attesting to the controlled/living character of such carbene-initiated polymerizations. It is argued that (1) adds to ethylene oxide to form a zwitterionic species, namely 1,3-bis-(diisopropyl)imidazol-2-ylidinium alkoxide, that further propagates by a zwitterionic ring-opening polymerization (ZROP) mechanism. Through an appropriate choice of terminating agent NuH or NuSiMe(3) at the completion of the polymerization, a variety of end-functionalized PEO chains could be generated. In particular, alpha,omega-bis(hydroxy)-telechelic PEO, alpha-benzyl,omega-hydroxy, and alpha-azido,omega-hydroxy-difunctionalized PEOs were synthesized by NHC (1)-initiated ZROP, using H(2)O, PhCH(2)OH, and N(3)SiMe(3) as terminating agent, respectively. Characterization of these alpha,omega-difunctionalized PEOs by techniques such as (1)H NMR spectroscopy, MALDI-TOF spectrometry, and size exclusion chromatography confirmed the quantitative introduction of functional groups at both alpha and omega positions of the PEO chains and the formation of very narrow molar mass polymers. Finally, the synthesis of a poly(ethylene oxide)-b-poly(epsilon-caprolactone) diblock copolymer by sequential ZROP of the corresponding monomers was successfully achieved using (1) as organic initiator without isolation of the PEO block intermediate.

  3. 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.

  4. Apparatus Circulates Sterilizing Gas

    NASA Technical Reports Server (NTRS)

    Cross, John H.; Schwarz, Ray P.

    1991-01-01

    Apparatus circulates sterilizing gas containing ethylene oxide and chlorofluorocarbon through laboratory or medical equipment. Confines sterilizing gas, circulating it only through parts to be treated. Consists of two units. One delivers ethylene oxide/chlorofluorocarbon gas mixture and removes gas after treatment. Other warms, humidifies, and circulates gas through equipment to be treated. Process provides reliable sterilization with negligible residual toxicity from ethylene oxide. Particularly suitable for sterilization of interiors of bioreactors, heart/lung machines, dialyzers, or other equipment including complicated tubing.

  5. Mortality study of ethylene oxide workers in chemical manufacturing: a 10 year update.

    PubMed

    Teta, M J; Benson, L O; Vitale, J N

    1993-08-01

    Men assigned to units producing ethylene oxide by the chlorohydrin or direct oxidation processes and to other departments using ethylene oxide in two chemical plants were followed up for mortality from 1940 to 1988 (n = 1896). Based on findings from a previous study of these workers to the end of 1978, which identified confounding exposures, workers assigned to one unit with low ethylene oxide exposure potential were excluded (n = 278). Average duration of exposure was over five years and average follow up was 27 years, with all subjects at least 10 years from first exposure. The data did not support associations of ethylene oxide with all cancer types combined, leukaemia, non-Hodgkin's lymphoma, or brain, pancreatic, or stomach cancers. There were also no duration-response trends. The standardised mortality ratio (SMR) for total cancer was 86 (95% confidence interval 71-104) and did not increase for those hired the earliest and with long duration assignments. The results of this 10 year update and those of other recent studies of ethylene oxide workers do not confirm findings from animal studies and are not consistent with the earliest results reported among ethylene oxide workers.

  6. Mortality study of ethylene oxide workers in chemical manufacturing: a 10 year update.

    PubMed Central

    Teta, M J; Benson, L O; Vitale, J N

    1993-01-01

    Men assigned to units producing ethylene oxide by the chlorohydrin or direct oxidation processes and to other departments using ethylene oxide in two chemical plants were followed up for mortality from 1940 to 1988 (n = 1896). Based on findings from a previous study of these workers to the end of 1978, which identified confounding exposures, workers assigned to one unit with low ethylene oxide exposure potential were excluded (n = 278). Average duration of exposure was over five years and average follow up was 27 years, with all subjects at least 10 years from first exposure. The data did not support associations of ethylene oxide with all cancer types combined, leukaemia, non-Hodgkin's lymphoma, or brain, pancreatic, or stomach cancers. There were also no duration-response trends. The standardised mortality ratio (SMR) for total cancer was 86 (95% confidence interval 71-104) and did not increase for those hired the earliest and with long duration assignments. The results of this 10 year update and those of other recent studies of ethylene oxide workers do not confirm findings from animal studies and are not consistent with the earliest results reported among ethylene oxide workers. PMID:8398856

  7. Novel Solid Encapsulation of Ethylene Gas Using Amorphous α-Cyclodextrin and the Release Characteristics.

    PubMed

    Ho, Binh T; Bhandari, Bhesh R

    2016-05-04

    This research investigated the encapsulation of ethylene gas into amorphous α-cyclodextrins (α-CDs) at low (LM) and high (HM) moisture contents at 1.0-1.5 MPa for 24-120 h and its controlled release characteristics at 11.2-52.9% relative humidity (RH) for 1-168 h. The inclusion complexes (ICs) were characterized using X-ray diffractometry (XRD), nuclear magnetic resonance spectroscopy (CP-MAS (13)C NMR), and scanning electron microscopy (SEM). Ethylene concentrations in the ICs were from 0.45 to 0.87 mol of ethylene/mol CD and from 0.42 to 0.54 mol of ethylene/mol CD for LM and HM α-CDs, respectively. Ethylene gas released from the encapsulated powder at higher rates with increasing RH. An analysis of release kinetics using Avrami's equation showed that the LM and HM amorphous α-CDs were not associated with significant differences in release constant k and parameter n for any given RH condition. NMR spectra showed the presence of the characteristic carbon-carbon double bond of ethylene gas in the encapsulated α-CD powder.

  8. Evaluation of the Carcinogenicity of Ethylene Oxide (2006 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.

  9. Fact Sheets: Final Air Toxics Rules for Ethylene Oxide Emissions from Commercial Sterilization and Fumigation Operations

    EPA Pesticide Factsheets

    This page contains November 1994 and November 1999 fact sheets with information regarding the Final Ethylene Oxide Emissions Standards for Sterilization Facilities. These documents contain answers to common questions for this NESHAP

  10. Ethylene Oxide Commerical Sterilization and Fumigation Operations National Emission Standards for Hazardous Air Pollutants (NESHAP)

    EPA Pesticide Factsheets

    The purpose of this document is to provide implementation materials to assist in conducting complete and efficient inspections at ethylene oxide commercial sterilization and fumigation operations to determine compliance with the NESHAP

  11. 46 CFR 154.1730 - Ethylene oxide: Loading and off loading.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Special Design and... tank vapor space is inerted with nitrogen. (b) Ethylene oxide must be off loaded by a deepwell pump...

  12. 46 CFR 154.1730 - Ethylene oxide: Loading and off loading.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Special Design and... tank vapor space is inerted with nitrogen. (b) Ethylene oxide must be off loaded by a deepwell pump...

  13. Evaluation of the Carcinogenicity of Ethylene Oxide (2006 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.

  14. How to respond to changes in the regulation of the ethylene-oxide sterilisation process.

    PubMed

    Young, William T

    2006-04-01

    The standards relating to ethylene-oxide sterilisation of medical devices are being revised. This article examines the implications of the changes for medical device manufacturers and advises what process innovations and other actions can be taken to ensure compliance.

  15. Direct Routes from Synthesis Gas to Ethylene Glycol.

    ERIC Educational Resources Information Center

    Dombek, B. D.

    1986-01-01

    Discusses the synthesis of ethylene glycol from carbon monoxide and hydrogen using bimetallic catalysts. Although this technology has not been implemented, it illustrates two important future trends, namely, use of bimetallic catalysts and use of coal-derived carbon monoxide and hydrogen as a new feed stock. (JN)

  16. Direct Routes from Synthesis Gas to Ethylene Glycol.

    ERIC Educational Resources Information Center

    Dombek, B. D.

    1986-01-01

    Discusses the synthesis of ethylene glycol from carbon monoxide and hydrogen using bimetallic catalysts. Although this technology has not been implemented, it illustrates two important future trends, namely, use of bimetallic catalysts and use of coal-derived carbon monoxide and hydrogen as a new feed stock. (JN)

  17. 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

    2015-02-27

    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. 2015 BMJ Publishing Group Ltd.

  18. Viscoelastic properties of poly(ethylene oxide) solution.

    PubMed

    Yu, D M; Amidon, G L; Weiner, N D; Goldberg, A H

    1994-10-01

    The viscoelastic properties of poly(ethylene oxide) (PEO) solution were investigated using the dynamic oscillatory testing technique. With this technique, the effect of PEO molecular weight (MW), concentration, composition of mixed solvent systems consisting of propylene glycol, glycerol formal, and water, and the effect of NaCl salt on the viscoelastic properties of PEO solution were determined. Dynamic moduli (G1, G2), magnitude of complex viscosity (magnitude of eta*), and loss tangent (tan delta) were examined over a frequency range of 10(-3)-2.5 Hz at 30 degrees C. The results indicated that low MW PEOs show liquidlike behavior while high elasticity is exhibited by high MW PEOs due to entanglement formation. The complex viscosity, magnitude of eta*, exhibits shear thinning (power-law) characteristics under oscillatory measurements. The relationship between steady shear and complex viscosities follows the Cox-Merz rule over the shear rate and frequency region studied. Both the storage (G1) and loss (G2) modulus increase drastically as the proportion of water in the mixed solvent system increases. Similarly, both G1 and G2 are found to increase while the tan delta decreases with increasing concentration of PEOs. The addition of up to 2% w/w NaCl in an aqueous solution of 10% w/w 2 million MW PEO has no observed detrimental effect on the viscoelastic behavior.

  19. Occupational exposure to ethylene oxide--OSHA. Final standard.

    PubMed

    1984-06-22

    In this Final Standard, the Occupational Safety and Health Administration (OSHA) establishes a permissible exposure limit for occupational exposure to ethylene oxide (EtO) of 1 part EtO per million parts of air (1 ppm) determined as an 8-hour time-weighted average concentration. The basis for this action is a determination by the Assistant Secretary, based on animal and human data, that exposure to EtO presents a carcinogenic, mutagenic, genotoxic, reproductive, neurologic and sensitization hazard to workers. The standard provides for, among other requirements, methods of exposure control, personal protective equipment, measurement of employee exposures, training, medical surveillance, signs and labels, regulated areas, emergency procedures and recordkeeping. An "action level" of 0.5 ppm as an 8-hour time-weighted average is established as the level above which employers must initiate certain compliance activities such as periodic employee exposure monitoring and medical surveillance. In instances where the employer can demonstrate that employee exposures are below the action level, the employer is not obligated to comply with most of the requirements set forth in this final rule. The 1 ppm 8-hour limit reduces significant risk from exposure to EtO and is considered by OSHA to be the lowest levels feasible.

  20. 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. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  1. An epidemiological study of workers potentially exposed to ethylene oxide.

    PubMed

    Wong, O; Trent, L S

    1993-04-01

    This epidemiological study was of 18,728 employees at 14 United States facilities producing sterilised medical supplies and spices, who were potentially exposed to ethylene oxide (EO) for at least 90 days. The mortality of the cohort was studied to the end of 1988. A total of 1353 deaths was identified. The cohort had a significantly lower mortality than the general population from all causes, all cancers, and non-malignant diseases. In the entire cohort, mortality was not significantly increased from any of the cancer sites examined. In particular, no significant increase in mortality was found in the cancer sites of interest based on previous studies--namely, stomach, leukaemia (including major specific cell types), pancreas, and brain. The lack of an increased mortality for these cancer sites was further strengthened by the lack of a dose-response relation with duration of employment and latency. Among the men, a statistically significant increase in mortality from non-Hodgkin's lymphoma was found. There was no indication for a dose-response relation for non-Hodgkin's lymphoma and no specific job categories seemed to be responsible for the increase. Among the women, a deficit of non-Hodgkin's lymphoma was found, which was not consistent with the finding in the men. Therefore, the increase among the men did not seem to be related to exposure to EO.

  2. An epidemiological study of workers potentially exposed to ethylene oxide.

    PubMed Central

    Wong, O; Trent, L S

    1993-01-01

    This epidemiological study was of 18,728 employees at 14 United States facilities producing sterilised medical supplies and spices, who were potentially exposed to ethylene oxide (EO) for at least 90 days. The mortality of the cohort was studied to the end of 1988. A total of 1353 deaths was identified. The cohort had a significantly lower mortality than the general population from all causes, all cancers, and non-malignant diseases. In the entire cohort, mortality was not significantly increased from any of the cancer sites examined. In particular, no significant increase in mortality was found in the cancer sites of interest based on previous studies--namely, stomach, leukaemia (including major specific cell types), pancreas, and brain. The lack of an increased mortality for these cancer sites was further strengthened by the lack of a dose-response relation with duration of employment and latency. Among the men, a statistically significant increase in mortality from non-Hodgkin's lymphoma was found. There was no indication for a dose-response relation for non-Hodgkin's lymphoma and no specific job categories seemed to be responsible for the increase. Among the women, a deficit of non-Hodgkin's lymphoma was found, which was not consistent with the finding in the men. Therefore, the increase among the men did not seem to be related to exposure to EO. PMID:8494770

  3. 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).

  4. Observation of the simplest Criegee intermediate CH2OO in the gas-phase ozonolysis of ethylene

    PubMed Central

    Womack, Caroline C.; Martin-Drumel, Marie-Aline; Brown, Gordon G.; Field, Robert W.; McCarthy, Michael C.

    2015-01-01

    Ozonolysis is one of the dominant oxidation pathways for tropospheric alkenes. Although numerous studies have confirmed a 1,3-cycloaddition mechanism that generates a Criegee intermediate (CI) with form R1R2COO, no small CIs have ever been directly observed in the ozonolysis of alkenes because of their high reactivity. We present the first experimental detection of CH2OO in the gas-phase ozonolysis of ethylene, using Fourier transform microwave spectroscopy and a modified pulsed nozzle, which combines high reactant concentrations with rapid sampling and sensitive detection. Nine other product species of the O3 + C2H4 reaction were also detected, including formaldehyde, formic acid, dioxirane, and ethylene ozonide. The presence of all these species can be attributed to the unimolecular and bimolecular reactions of CH2OO, and their abundances are in qualitative agreement with published mechanisms and rate constants. PMID:26601145

  5. Observation of the simplest Criegee intermediate CH2OO in the gas-phase ozonolysis of ethylene.

    PubMed

    Womack, Caroline C; Martin-Drumel, Marie-Aline; Brown, Gordon G; Field, Robert W; McCarthy, Michael C

    2015-03-01

    Ozonolysis is one of the dominant oxidation pathways for tropospheric alkenes. Although numerous studies have confirmed a 1,3-cycloaddition mechanism that generates a Criegee intermediate (CI) with form R1R2COO, no small CIs have ever been directly observed in the ozonolysis of alkenes because of their high reactivity. We present the first experimental detection of CH2OO in the gas-phase ozonolysis of ethylene, using Fourier transform microwave spectroscopy and a modified pulsed nozzle, which combines high reactant concentrations with rapid sampling and sensitive detection. Nine other product species of the O3 + C2H4 reaction were also detected, including formaldehyde, formic acid, dioxirane, and ethylene ozonide. The presence of all these species can be attributed to the unimolecular and bimolecular reactions of CH2OO, and their abundances are in qualitative agreement with published mechanisms and rate constants.

  6. Rapid determination of ethylene oxide with fiber-packed sample preparation needle.

    PubMed

    Ueta, Ikuo; Saito, Yoshihiro; Ghani, Nadia Binti Abdul; Ogawa, Mitsuhiro; Yogo, Kentaro; Abe, Akira; Shirai, Shingoro; Jinno, Kiyokatsu

    2009-04-03

    Fiber-packed sample preparation device was applied to the simultaneous derivatization/preconcentration of ethylene oxide (EO) in air samples. The polymer-coated filaments were packed longitudinally into the needle, and hydrogen bromide (HBr) was loaded onto the filaments in the preconditioning process. Simultaneous derivatization with HBr in the needle was made during the sampling process of the gaseous EO, and the corresponding derivatized analyte, 2-bromoethanol, was desorbed by passing a small amount of methanol through the extraction needle in the heated gas chromatograph (GC) injector. The basic extraction/desorption parameters for EO have been evaluated. The limit of detection (LOD), limit of quantification (LOQ) and the relative standard deviation (RSD) of run-to-run repeatability were 1.8 ng/L, 5.4 ng/L and less than 4%, respectively, with an extraction time of about 10 min. Satisfactory storage performance for three days at room temperature was also confirmed.

  7. Carbon Nanotube- and Carbon Fiber-Reinforcement of Ethylene-Octene Copolymer Membranes for Gas and Vapor Separation

    PubMed Central

    Sedláková, Zuzana; Clarizia, Gabriele; Bernardo, Paola; Jansen, Johannes Carolus; Slobodian, Petr; Svoboda, Petr; Kárászová, Magda; Friess, Karel; Izak, Pavel

    2014-01-01

    Gas and vapor transport properties were studied in mixed matrix membranes containing elastomeric ethylene-octene copolymer (EOC or poly(ethylene-co-octene)) with three types of carbon fillers: virgin or oxidized multi-walled carbon nanotubes (CNTs) and carbon fibers (CFs). Helium, hydrogen, nitrogen, oxygen, methane, and carbon dioxide were used for gas permeation rate measurements. Vapor transport properties were studied for the aliphatic hydrocarbon (hexane), aromatic compound (toluene), alcohol (ethanol), as well as water for the representative samples. The mechanical properties and homogeneity of samples was checked by stress-strain tests. The addition of virgin CNTs and CFs improve mechanical properties. Gas permeability of EOC lies between that of the more permeable PDMS and the less permeable semi-crystalline polyethylene and polypropylene. Organic vapors are more permeable than permanent gases in the composite membranes, with toluene and hexane permeabilities being about two orders of magnitude higher than permanent gas permeability. The results of the carbon-filled membranes offer perspectives for application in gas/vapor separation with improved mechanical resistance. PMID:24957119

  8. Carbon nanotube- and carbon fiber-reinforcement of ethylene-octene copolymer membranes for gas and vapor separation.

    PubMed

    Sedláková, Zuzana; Clarizia, Gabriele; Bernardo, Paola; Jansen, Johannes Carolus; Slobodian, Petr; Svoboda, Petr; Kárászová, Magda; Friess, Karel; Izak, Pavel

    2014-01-03

    Gas and vapor transport properties were studied in mixed matrix membranes containing elastomeric ethylene-octene copolymer (EOC or poly(ethylene-co-octene)) with three types of carbon fillers: virgin or oxidized multi-walled carbon nanotubes (CNTs) and carbon fibers (CFs). Helium, hydrogen, nitrogen, oxygen, methane, and carbon dioxide were used for gas permeation rate measurements. Vapor transport properties were studied for the aliphatic hydrocarbon (hexane), aromatic compound (toluene), alcohol (ethanol), as well as water for the representative samples. The mechanical properties and homogeneity of samples was checked by stress-strain tests. The addition of virgin CNTs and CFs improve mechanical properties. Gas permeability of EOC lies between that of the more permeable PDMS and the less permeable semi-crystalline polyethylene and polypropylene. Organic vapors are more permeable than permanent gases in the composite membranes, with toluene and hexane permeabilities being about two orders of magnitude higher than permanent gas permeability. The results of the carbon-filled membranes offer perspectives for application in gas/vapor separation with improved mechanical resistance.

  9. Emission of ethylene oxide during frying of foods in soybean oil.

    PubMed

    Lin, Jiune-Shyoung; Chuang, Karl T; Huang, Mao-Sun; Wei, Kuo-Ming

    2007-04-01

    High levels of ethylene oxide (EO) and acetaldehyde (AE) were detected, using gas chromatography and a portable gas detector, among volatile organic compounds (VOC) emitted during simulated frying of herbs and spices in soybean oil at temperatures between 120 degrees C and 200 degrees C. Both EO and AE were distributed between the gas phase and oil phase after cooking each vegetable at 150 degrees C for 5min under either nitrogen or air at 1atm. EO concentrations in the gas phase (25-75ppm) exceeded the threshold limit value of 1ppm, the TLV TWA value established by the American Conference of Government Industrial Hygienists and permitted by the Occupational Safety and Health Administration. EO has been identified as a significant carcinogen. Thus, while no causal relationship can be concluded from this study, the results suggest a possible relationship between the high levels of EO emitted during frying and the high incidence of lung cancer among Taiwanese women engaged in traditional cooking.

  10. Gas-film coefficients for the volatilization of ethylene dibromide from water

    USGS Publications Warehouse

    Rathbun, R.E.; Tal, D.Y.

    1986-01-01

    Gas-film coefficients for the volatilization of ethylene dibromide (EDB) and water were determined in the laboratory as a function of wind speed and temperature. The ratio of the coefficients was independent of wind speed and increased slightly with temperature. Use of this ratio with an environmentally determined gas-film coefficient for the evaporation of water permits determination of the gas-film coefficient for the volatilization of EDB from environmental waters.

  11. Ion-Conductive Properties of a Polymer Electrolyte Based on Ethylene Carbonate/Ethylene Oxide Random Copolymer.

    PubMed

    Morioka, Takashi; Nakano, Koji; Tominaga, Yoichi

    2017-02-21

    A random copolymer of ethylene oxide with CO2 , namely, poly(ethylene carbonate/ethylene oxide) (P(EC/EO)), has been synthesized as a novel candidate for polymer electrolytes. Electrolyte composed of P(EC/EO) and lithium bis(fluorosulfonyl)imide has an ionic conductivity of 0.48 mS cm(-1) and a Li transference number (t + ) of 0.66 at 60 °C. To study ion-conductive behavior of P(EC/EO)-based electrolytes, the Fourier transform infrared (FT-IR) technique is used to analyze the interactions between Li(+) and functional groups of the copolymer. The carbonate groups may interact preferentially with Li(+) rather than the ether groups in P(EC/EO). This study suggests that copolymerization of carbonate and flexible ether units can realize both high conductivity and t + for polymer electrolytes. High-performance P(EC/EO) electrolyte is expected to be a candidate material for use in all-solid-state batteries.

  12. Physico-chemical and toxicologo-hygienic aspects of using ethylene oxide for the sterilization of medical appliances. Part I. Sorption and diffusion of ethylene oxide in polymeric materials.

    PubMed

    Lyarskii, P P; Likhtman, T V; Kareyev, N V; Komarkova, N I; Gleiberman, S E

    1984-01-01

    Sorption ability of polymeric materials for medical purposes was studied with respect to the sterilizing gas - ethylene oxide - at 23, 35 and 55 degrees C. Sorption coefficients of ethylene oxide (EO) for the materials under study were calculated on the basis of results. Investigation of the kinetics of desorption of EO from the polymeric materials for medical purposes has shown that its content changes exponentially depending on the time of degassing. However, the lines in the 1g Q/Q0 - tau coordinates show a sharp break which testifies to a change in the mechanism of the process determining the character of the mentioned dependence. In the first region, corresponding to high concentrations and short periods of time, the determining process is diffusion while in the second region (low concentrations, long time intervals) - it is desorption of EO molecules most firmly bound to the polymer. Diffusion coefficients were calculated for the first region. The possibility of predicting the time periods of removing ethylene oxide from the polymeric materials was demonstrated for both stages on the basis of calculated diffusion coefficients and kinetic curves of degassing. Recommendations were given for the use of polymers for medical appliances and apparatuses.

  13. Cancer incidence in Swedish sterilant workers exposed to ethylene oxide.

    PubMed

    Hagmar, L; Mikoczy, Z; Welinder, H

    1995-03-01

    To assess the risk of cancer, especially leukaemia, in a cohort of sterilant workers exposed to ethylene oxide (EtO). A cohort of 2170 workers employed for at least one year in two plants that produce disposable medical equipment sterilised with EtO has previously been established. The results of an update with four more years of observation are presented. The cancer incidence was assessed for the periods 1976 to 1990 and 1972 to 1990 and cause specific standardised incidence ratios (SIRs) were calculated. Individual cumulative exposure to EtO, expressed as ppm-years, was estimated and used in exposure-response analyses. Six lymphohaematopoietic tumours were observed (SIR 1.78, 95% confidence interval (95% CI) 0.65-3.88), of which two were leukaemias (SIR 2.44; 95% CI 0.30-8.81). When those with cumulative exposures to EtO below the median value (0.13 ppm-years) were excluded, and a minimum of 10 years induction latency period was applied, the incidence ratio for leukaemia increased further (SIR 7.14, 95% CI 0.87-25.8), but was still not significantly enhanced. The risk estimate for leukaemia increased, but non-significantly, with time since start of exposure, and with cumulative exposures to EtO above the median value. The subjects with leukaemia had, however, only slightly higher cumulative exposure estimates for EtO than the average cohort member. Nevertheless, the present results may add some minor evidence for an association between EtO and an increased risk of leukaemia.

  14. 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.

  15. GAS-PHASE FLAME SYNTHESIS AND PROPERTIES OF MAGNETIC IRON OXIDE NANOPARTICLES WITH REDUCED OXIDATION STATE

    PubMed Central

    Kumfer, Benjamin M; Shinoda, Kozo; Jeyadevan, Balachandran; Kennedy, Ian M

    2010-01-01

    Iron oxide nanoparticles of reduced oxidation state, mainly in the form of magnetite, have been synthesized utilizing a new continuous, gas-phase, nonpremixed flame method using hydrocarbon fuels. This method takes advantage of the characteristics of the inverse flame, which is produced by injection of oxidizer into a surrounding flow of fuel. Unlike traditional flame methods, this configuration allows for the iron particle formation to be maintained in a more reducing environment. The effects of flame temperature, oxygen-enrichment and fuel dilution (i.e. the stoichiometric mixture fraction), and fuel composition on particle size, Fe oxidation state, and magnetic properties are evaluated and discussed. The crystallite size, Fe(II) fraction, and saturation magnetization were all found to increase with flame temperature. Flames of methane and ethylene were used, and the use of ethylene resulted in particles containing metallic Fe(0), in addition to magnetite, while no Fe(0) was present in samples synthesized using methane. PMID:20228941

  16. Induction of alternative respiratory pathway involves nitric oxide, hydrogen peroxide and ethylene under salt stress.

    PubMed

    Wang, Huahua; Huang, Junjun; Bi, Yurong

    2010-12-01

    Alternative respiratory pathway (AP) plays an important role in plant thermogenesis, fruit ripening and responses to environmental stresses. AP may participate in the adaptation to salt stress since salt stress increased the activity of the AP. Recently, new evidence revealed that ethylene and hydrogen peroxide (H(2)O(2)) are involved in the salt-induced increase of the AP, which plays an important role in salt tolerance in Arabidopsis callus, and ethylene may be acting downstream of H(2)O(2). Recent observations also indicated both ethylene and nitric oxide (NO) act as signaling molecules in responses to salt stress, and ethylene may be a part of the downstream signal molecular in NO action. In this addendum, a hypothetical model for NO function in regulation of H(2)O(2)- and ethylene-mediated induction of AP under salt stress is presented.

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

    PubMed

    Xing, Lidan; Borodin, Oleg

    2012-10-05

    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.

  18. Ethylene oxide: evaluation of genotoxicity data and an exploratory assessment of genetic risk.

    PubMed

    Natarajan, A T; Preston, R J; Dellarco, V; Ehrenberg, L; Generoso, W; Lewis, S; Tates, A D

    1995-08-01

    A risk estimate of the heritable effects of ethylene oxide exposure, using the parallelogram approach, as suggested by Frits Sobels, is described. The approach is based on available data on the ethylene oxide-induced responses for the same genetic endpoint in somatic cells of both laboratory animals and humans, and for germ cell mutations in the same laboratory animal. Human germ cell effects are estimated. The available data sets for this approach were evaluated. We consider this as complementary to the genetic risk assessment carried out by U.S. EPA scientists, in which the risk from heritable (reciprocal) translocations induced by ethylene oxide was estimated. In the present study we restricted our assessment to dominant mutations. The sensitivity factor relating mouse to man was based on ethylene oxide-induced HPRT mutant frequencies in lymphocytes in vivo. From this comparison, it could be concluded that occupational exposure for 1 year to 1 ppm ethylene oxide would lead to a risk of a dominantly inherited disease in the offspring of 4 x 10(-4) above the background level. The uncertainty interval of this figure is quite large (0.6-28) x 10(-4). The values are compatible with the existing estimates of the corresponding risk from exposure to low LET radiation when the genotoxic potency ratio of ethylene oxide and radiation is considered. This risk estimation approach has allowed us to identify additional data that are required for a more complete risk estimation of the heritable effects of ethylene oxide, or indeed any mutagenic chemical.

  19. 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.

  20. Multiple phase transition and scaling law for poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer in aqueous solution.

    PubMed

    Liu, Sijun; Li, Lin

    2015-02-04

    The multiple phase transition and the scaling behavior of a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (Pluronic F127, PEO100-PPO65-PEO100) have been studied by micro-differential scanning calorimetry and rheology. The scaling behavior of the triblock copolymer was examined using the Winter-Chambon criterion to obtain the critical gel temperature Tgel and the scaling exponent n. n was found to decrease linearly with increasing copolymer concentration. A stable hard gel was formed, but the hard gel was transformed into a soft gel upon further heating. Increasing copolymer concentration led to the increase in the temperature of hard-soft gel transition, while the sol-gel transition temperature decreased with increasing copolymer concentration. A phase diagram has been determined, which is able to classify unimers, micelles, hard gel, and soft gel regions upon heating. In addition, the scaling relation of the plateau modulus Ge with copolymer concentration was also obtained as Ge ≈ c(3.0) for both soft gel and hard gel.

  1. 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.

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

    DOE PAGES

    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

  3. 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.

  4. A rapid analysis of plasma/serum ethylene and propylene glycol by headspace gas chromatography.

    PubMed

    Ehlers, Alexandra; Morris, Cory; Krasowski, Matthew D

    2013-12-01

    A rapid headspace-gas chromatography (HS-GC) method was developed for the analysis of ethylene glycol and propylene glycol in plasma and serum specimens using 1,3-propanediol as the internal standard. The method employed a single-step derivitization using phenylboronic acid, was linear to 200 mg/dL and had a lower limit of quantitation of 1 mg/dL suitable for clinical analyses. The analytical method described allows for laboratories with HS-GC instrumentation to analyze ethanol, methanol, isopropanol, ethylene glycol, and propylene glycol on a single instrument with rapid switch-over from alcohols to glycols analysis. In addition to the novel HS-GC method, a retrospective analysis of patient specimens containing ethylene glycol and propylene glycol was also described. A total of 36 patients ingested ethylene glycol, including 3 patients who presented with two separate admissions for ethylene glycol toxicity. Laboratory studies on presentation to hospital for these patients showed both osmolal and anion gap in 13 patients, osmolal but not anion gap in 13 patients, anion but not osmolal gap in 8 patients, and 1 patient with neither an osmolal nor anion gap. Acidosis on arterial blood gas was present in 13 cases. Only one fatality was seen; this was a patient with initial serum ethylene glycol concentration of 1282 mg/dL who died on third day of hospitalization. Propylene glycol was common in patients being managed for toxic ingestions, and was often attributed to iatrogenic administration of propylene glycol-containing medications such as activated charcoal and intravenous lorazepam. In six patients, propylene glycol contributed to an abnormally high osmolal gap. The common presence of propylene glycol in hospitalized patients emphasizes the importance of being able to identify both ethylene glycol and propylene glycol by chromatographic methods.

  5. Laboratory evaluation of stain-length passive dosimeters for monitoring of vinyl chloride and ethylene oxide

    SciTech Connect

    Gonzalez, L.A.; Sefton, M.V.

    1985-10-01

    The effects of vapor concentration in the range of 1.2 to 5.1 ppm (vinyl chloride) and 8.3 to 29.1 ppm (ethylene oxide) on the response of new stain-length passive dosimeters were evaluated separately in a dynamic exposure chamber. The vinyl chloride dosimeter was prepared with a permanganate impregnated blend of Chromosorb W and silica gel, while a silica gel-coated plastic strip (TLC plate) impregnated with dichromate was used to detect ethylene oxide. The use of a TLC plate as the inert support allowed us to reduce the amount of reagent loaded per length of tube, thus significantly enhancing in the sensitivity of the unit, which was necessary for accurately detecting ethylene oxide at these low concentrations. At the vinyl chloride exposure of 8 ppm-hrs the length of stain was 0.76 cm and the 95% confidence interval about this point was +/- 1.4 ppm-hrs (18%). For the ethylene oxide dosimeter the length of stain at the exposure of 80 ppm-hrs was 0.90 cm and the 95% confidence interval about this point was +/- 16 ppm-hrs (20%). The ethylene oxide dosimeter response was not affected by relative humidity in the range of 28 to 90%. The use of a TLC plate as the inert support of the colorimetric reagent has proven to be an excellent means of improving the sensitivity of these stain-length passive dosimeters.

  6. Physical effects of reuse and repeated ethylene oxide sterilization on transscleral cyclophotocoagulation laser G-probes.

    PubMed

    Tham, Clement C Y; Lai, Jimmy S M; Fung, Peter C W; Chua, John K H; Poon, Agnes S Y; Lam, Dennis S C

    2002-02-01

    The authors documented the physical effects of reuse and repeated ethylene oxide sterilization on transscleral cyclophotocoagulation laser G-probes. Transscleral cyclophotocoagulation was performed using G-probes on fresh porcine eyes. Each of two G-probes was used for four transscleral cyclophotocoagulation procedures, with three cycles of ethylene oxide sterilization in between. The power output from the G-probes was measured by a laser output meter before and after each transscleral cyclophotocoagulation procedure. The G-probes were also examined under a slit lamp for signs of physical damage. Repeated use of the G-probe in transscleral cyclophotocoagulation, with ethylene oxide sterilization in between, resulted in an average decrease of 3% in laser energy delivered per repeated cycle of use up to the fourth cycle. No signs of physical damage were found. Laser G-probes remain functional after repeated use and ethylene oxide resterilization for up to four cycles. No visible physical damage to the probes was identified. It is safe and cost-effective to reuse G-probe for transscleral cyclophotocoagulation with ethylene oxide sterilization, provided the surgeon stays alert for signs of probe damage. This alertness should be retained regardless of whether new or old G-probes are used.

  7. Ethylene oxide: an assessment of the epidemiological evidence on carcinogenicity.

    PubMed

    Shore, R E; Gardner, M J; Pannett, B

    1993-11-01

    Mortality from cancer among workers exposed to ethylene oxide (EtO) has been studied in 10 distinct cohorts that include about 29,800 workers and 2540 deaths. This paper presents a review and meta-analysis of these studies, primarily for leukaemia, non-Hodgkin's lymphoma, stomach cancer, pancreatic cancer, and cancer of the brain and nervous system. The magnitude and consistency of the standardised mortality ratios (SMRs) were evaluated for the individual and combined studies, as well as trends by intensity or frequency of exposure, by duration of exposure, and by latency (time since first exposure). Exposures to other workplace chemicals were examined as possible confounder variables. Three small studies by Hogstedt initially suggested an association between EtO and leukaemia, but in seven subsequent studies the SMRs for leukaemia have been much lower. For the combined studies the SMR = 1.06 (95% confidence interval (95% CI) 0.73-1.48). There was a slight suggestion of a trend by duration of exposure (p = 0.19) and a suggested increase with longer latency (p = 0.07), but there was no overall trend in risk of leukaemia by intensity or frequency of exposure; nor did a cumulative exposure analysis in the largest study indicate a quantitative association. There was also an indication that in two studies with increased risks the workers had been exposed to other potential carcinogens. For non-Hodgkin's lymphoma there was a suggestive risk overall (SMR = 1.35, 95% CI 0.93-1.90). Breakdowns by exposure intensity or frequency, exposure duration, or latency did not indicate an association, but a positive trend by cumulative exposure (p = 0.05) was seen in the largest study. There was a suggested increase in the overall SMR for stomach cancer (SMR = 1.28, 95% CI 0.98-1.65 (CI 0.73-2.26 when heterogeneity among the risk estimates was taken into account)), but analyses by intensity or duration of exposure or cumulative exposure did not support a causal association for stomach

  8. Ethylene oxide: an assessment of the epidemiological evidence on carcinogenicity.

    PubMed Central

    Shore, R E; Gardner, M J; Pannett, B

    1993-01-01

    Mortality from cancer among workers exposed to ethylene oxide (EtO) has been studied in 10 distinct cohorts that include about 29,800 workers and 2540 deaths. This paper presents a review and meta-analysis of these studies, primarily for leukaemia, non-Hodgkin's lymphoma, stomach cancer, pancreatic cancer, and cancer of the brain and nervous system. The magnitude and consistency of the standardised mortality ratios (SMRs) were evaluated for the individual and combined studies, as well as trends by intensity or frequency of exposure, by duration of exposure, and by latency (time since first exposure). Exposures to other workplace chemicals were examined as possible confounder variables. Three small studies by Hogstedt initially suggested an association between EtO and leukaemia, but in seven subsequent studies the SMRs for leukaemia have been much lower. For the combined studies the SMR = 1.06 (95% confidence interval (95% CI) 0.73-1.48). There was a slight suggestion of a trend by duration of exposure (p = 0.19) and a suggested increase with longer latency (p = 0.07), but there was no overall trend in risk of leukaemia by intensity or frequency of exposure; nor did a cumulative exposure analysis in the largest study indicate a quantitative association. There was also an indication that in two studies with increased risks the workers had been exposed to other potential carcinogens. For non-Hodgkin's lymphoma there was a suggestive risk overall (SMR = 1.35, 95% CI 0.93-1.90). Breakdowns by exposure intensity or frequency, exposure duration, or latency did not indicate an association, but a positive trend by cumulative exposure (p = 0.05) was seen in the largest study. There was a suggested increase in the overall SMR for stomach cancer (SMR = 1.28, 95% CI 0.98-1.65 (CI 0.73-2.26 when heterogeneity among the risk estimates was taken into account)), but analyses by intensity or duration of exposure or cumulative exposure did not support a causal association for stomach

  9. Coarse-graining poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymers using the MARTINI force field.

    PubMed

    Nawaz, Selina; Carbone, Paola

    2014-02-13

    The MARTINI coarse-grain (CG) force field is extended for a class of triblock block copolymers known as Pluronics. Existing MARTINI bead types are used to model the non-bonded part of the potential while single chain properties for both homopolymers, poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO), are used to develop the bonded interactions. The new set of force field parameters reproduces structural and dynamical properties of high molecular weight homo- and copolymers. The CG model is moderately transferable in solvents of different polarity and concentration; however, the PEO homopolymer model presents a reduced thermodynamic transferability especially in water probably due to the lack of hydrogen bonds with the solvent. Our simulations of a monolayer of Pluronic L44 show polymer-brush-like characteristics for the PEO segments which protrude into the aqueous phase. Other membrane properties not easily accessible using experimental techniques such as its membrane thickness are also calculated.

  10. Theoretical investigations on oxidative stability of solvents and oxidative decomposition mechanism of ethylene carbonate for lithium ion battery use.

    PubMed

    Xing, Lidan; Li, Weishan; Wang, Chaoyang; Gu, Fenglong; Xu, Mengqing; Tan, Chunlin; Yi, Jin

    2009-12-31

    The electrochemical oxidative stability of solvent molecules used for lithium ion battery, ethylene carbonate (EC), propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate in the forms of simple molecule and coordination with anion PF(6)(-), is compared by using density functional theory at the level of B3LYP/6-311++G (d, p) in gas phase. EC is found to be the most stable against oxidation in its simple molecule. However, due to its highest dielectric constant among all the solvent molecules, EC coordinates with PF(6)(-) most strongly and reaches cathode most easily, resulting in its preferential oxidation on cathode. Detailed oxidative decomposition mechanism of EC is investigated using the same level. Radical cation EC(*+) is generated after one electron oxidation reaction of EC and there are five possible pathways for the decomposition of EC(*+) forming CO(2), CO, and various radical cations. The formation of CO is more difficult than CO(2) during the initial decomposition of EC(*+) due to the high activation energy. The radical cations are reduced and terminated by gaining one electron from anode or solvent molecules, forming aldehyde and oligomers of alkyl carbonates including 2-methyl-1,3-dioxolane, 1,3,6-trioxocan-2-one, 1,4,6,9-tetraoxaspiro[4.4]nonane, and 1,4,6,8,11-pentaoxaspiro[4.6]undecan-7-one. The calculation in this paper gives a detailed explanation on the experimental findings that have been reported in literatures and clarifies the mechanism on the oxidative decomposition of EC.

  11. 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.

  12. Ethylene production is associated with alleviation of cadmium-induced oxidative stress by sulfur in mustard types differing in ethylene sensitivity.

    PubMed

    Asgher, Mohd; Khan, Nafees A; Khan, M Iqbal R; Fatma, Mehar; Masood, Asim

    2014-08-01

    We studied the response of ethylene-sensitive (Pusa Jai Kisan) and ethylene-insensitive (SS2) mustard (Brassica juncea) cultivars to 0, 0.5, 1.0 and 2.0 mM SO₄(2-), and the effect of 1.0 mM SO₄(2-) was studied in the amelioration of 50 µM cadmium (Cd). The Cd-induced oxidative stress and Cd accumulation were greater in SS2 than Pusa Jai Kisan, but sulfur (S) application alleviated Cd-induced oxidative stress more prominently in Pusa Jai Kisan by increasing S-metabolism and synthesis of reduced glutathione (GSH) and ethylene production; and promoted photosynthesis and plant dry mass under Cd stress. The ethylene-sensitive cultivar responded more to S treatment under Cd stress and showed increased activity of antioxidant system resulting in increased photosynthesis and growth. Cadmium treatment resulted in rapid increase in ethylene formation which adversely influenced photosynthesis and plant dry mass. However, S and ethephon application to Cd-treated plants lowered ethylene formation to optimal range responsible for maximal GSH synthesis and protection against Cd-induced oxidative stress. The similarity of the effectiveness of 1.0 mM SO₄(2-) with 200 µL L(-1) ethylene source as ethephon in alleviation of 50 µM Cd further verifies that differential alleviation of Cd toxicity in the two cultivars by S was dependent on ethylene production. The results suggest that ethylene production determines Cd stress alleviation by S via regulatory interaction with antioxidant metabolism. Thus, ethylene production and sensitivity bear a prominent role in alleviation of Cd stress by S and can be used as a criterion for developing Cd tolerant genotypes. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. 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

  14. An investigation of molybdenum and molybdenum oxide catalyzed hydrocarbon formation reactions. [Surface chemistry of ethylene oxide on Pd(111)

    SciTech Connect

    Not Available

    1993-01-01

    Progress was made in the following four areas: activity of model catalyst (Mo oxides) for olefin metathesis (2 C[sub 3]H[sub 6] [r arrow] C[sub 4]H[sub 8] + C[sub 2]H[sub 4]); kinetics of Mo(100)-catalyzed olefin metathesis; surface chemistry of ethylene oxide on Pd(111); and uv source construction.

  15. Genotoxic effects of ethylene oxide, propylene oxide and epichlorohydrin in humans: update review (1990-2001).

    PubMed

    Kolman, Ada; Chovanec, Miroslav; Osterman-Golkar, Siv

    2002-12-01

    Ethylene oxide (EtO), propylene oxide (PO) and epichlorohydrin (ECH) are important industrial chemicals widely used as intermediates for various synthetic products. EtO and PO are also environmental pollutants. In this review we summarize data published during the period 1990-2001 concerning both the genotoxic and carcinogenic effects of these epoxides in humans. The use of DNA and hemoglobin adducts as biomarkers of exposure and the role of polymorphism, as well as confounding factors, are discussed. We have also included recent in vitro data comprising genotoxic effects induced by EtO, PO and ECH in mammalian cells. The uncertainties regarding cancer risk estimation still persist, in spite of the large database collected.

  16. [Development of the method for determining substances--markers of the hazardous production of advanced oil processing (ethylene oxide, 1,3-butadiene) in the air at the level of reference concentrations].

    PubMed

    2012-01-01

    The results of experimental studies on the development of gas chromatographic method for the determination of 1,3-butadiene and ethylene oxide in ambient air at the level of reference concentration with the use of sorption of the compounds studied from ambient air on the adsorbent TenaxTA in conjunction with optimum conditions of thermal desorption and the use of capillary gas chromatography are presented. The parameters of adsorption, thermal desorption and gas chromatographic determination of 1,3-butadiene and ethylene oxide in ambient air have been justified. A high sensitivity of gas chromatographic determination in the range of concentrations (in mg/m3) of 1,3-butadiene, 0,002 - 5, 0, ethylene oxide 0.005 - 1, 0 with 25% uncertainty in the determination has been reached .

  17. Enhancement of convective heat transfer coefficient of ethylene glycol base cuprous oxide (Cu2O) nanofluids

    NASA Astrophysics Data System (ADS)

    Hassan, Ali; Ramzan, Naveed; Umer, Asim; Ahmad, Ayyaz; Muryam, Hina

    2017-08-01

    The enhancement in the convective heat transfer coefficient of the ethylene glycol (EG) base cuprous oxide (Cu2O) nanofluids were investigated. The nanofluids of different volume concentrations i-e 1%, 2.5% and 4.5% were prepared by the two step method. Cuprous oxide (Cu2O) nanoparticles were ultrasonically stirred for four hours in the ethylene glycol (EG). The experimental study has been performed through circular tube geometry in laminar flow regime at average Reynolds numbers 36, 71 and 116. The constant heat flux Q = 4000 (W/m2) was maintained during this work. Substantial enhancement was observed in the convective heat transfer coefficient of ethylene glycol (EG) base cuprous oxide (Cu2O) nanofluids than the base fluid. The maximum 74% enhancement was observed in convective heat transfer coefficient at 4.5 vol% concentration and Re = 116.

  18. 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

    2016-05-03

    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.

  19. Ethylene and nitric oxide are involved in maintaining ion homeostasis in Arabidopsis callus under salt stress.

    PubMed

    Wang, Huahua; Liang, Xiaolei; Wan, Qi; Wang, Xiaomin; Bi, Yurong

    2009-07-01

    In the present study, the role of ethylene in nitric oxide (NO)-mediated protection by modulating ion homeostasis in Arabidopsis callus under salt stress was investigated. Results showed that the ethylene-insensitive mutant etr1-3 was more sensitive to salt stress than the wild type (WT). Under 100 mM NaCl, etr1-3 callus displayed a greater electrolyte leakage and Na(+)/K(+) ratio but a lower plasma membrane (PM) H(+)-ATPase activity compared to WT callus. Application of exogenous 1-aminocyclopropane-1-carboxylic acid (ACC, an ethylene precursor) or sodium nitroprusside (SNP, a NO donor) alleviated NaCl-induced injury by maintaining a lower Na(+)/K(+) ratio and an increased PM H(+)-ATPase activity in WT callus but not in etr1-3 callus. The SNP actions in NaCl stress were attenuated by a specific NO scavenger or an ethylene biosynthesis inhibitor in WT callus. Under 100 mM NaCl, the NO accumulation and ethylene emission appeared at early time, and NO production greatly stimulated ethylene emission in WT callus. In addition, ethylene induced the expression of PM H(+)-ATPase genes under salt stress. The recovery experiment showed that NaCl-induced injury was reversible, as signaled by the similar recovery of Na(+)/K(+) ratio and PM H(+)-ATPase activity in WT callus. Taken together, the results indicate that ethylene and NO cooperate in stimulating PM H(+)-ATPase activity to modulate ion homeostasis for salt tolerance, and ethylene may be a part of the downstream signal molecular in NO action.

  20. Dormancy removal in apple embryos by nitric oxide or cyanide involves modifications in ethylene biosynthetic pathway.

    PubMed

    Gniazdowska, Agnieszka; Krasuska, Urszula; Bogatek, Renata

    2010-11-01

    The connection between classical phytohormone-ethylene and two signaling molecules, nitric oxide (NO) and hydrogen cyanide (HCN), was investigated in dormancy removal and germination "sensu stricto" of apple (Malus domestica Borkh.) embryos. Deep dormancy of apple embryos was removed by short-term (3-6 h) pre-treatment with NO or HCN. NO- or HCN-mediated stimulation of germination was associated with enhanced emission of ethylene by the embryos, coupled with transient increase in ROS concentration in embryos. Ethylene vapors stimulated germination of dormant apple embryos and eliminated morphological anomalies characteristic for young seedlings developed from dormant embryos. Inhibitors of ethylene receptors completely impeded beneficial effect of NO and HCN on embryo germination. NO- and HCN-induced ethylene emission by apple embryo was only slightly reduced by inhibitor of 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase activity during first 4 days of germination. Short-term pre-treatment of the embryos with NO and HCN modified activity of both key enzymes of ethylene biosynthetic pathway: ACC synthase and ACC oxidase. Activity of ACC synthase declined during first 4 days of germination, while activity of ACC oxidase increased markedly at that time. Additional experiments point to non-enzymatic conversion of ACC to ethylene in the presence of ROS (H(2)O(2)). The results indicate that NO and HCN may alleviate dormancy of apple embryos "via" transient accumulation of ROS, leading to enhanced ethylene emission which is required to terminate germination "sensu stricto". Therefore, ethylene seems to be a trigger factor in control of apple embryo dormancy removal and germination.

  1. Oxidative Condensation of Methane — a New Pathway to the Synthesis of Ethane, Ethylene, and Other Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Minachev, Khabib M.; Usachev, Nikolay Ya; Udut, V. N.; Khodakov, Yu S.

    1988-03-01

    During the last five years, the chemistry of methane has been enriched by the possibility of obtaining C2 and other hydrocarbons as a result of the oxidative condensation of methane in the presence of a series of catalytic systems. The availability of the starting materials (CH4 and O2) leads to extensive prospects for the replacement of the petroleum raw materials by natural gas in single-stage syntheses of valuable compounds and in the first place ethylene. This review gives a systematic account of the results of the selection of effective catalysts and surveys the information leading to the elucidation of the mechanism for the formation of the products of the extensive oxidation and oxidative condensation of methane. The bibliography includes 118 references.

  2. Industry-wide hygiene walk-through survey report of Kendall Company, Augusta Facility, Augusta, Georgia. [Ethylene oxide

    SciTech Connect

    Steenland, K.; Stayner, L.; Elliott, L.; Ringenburg, V.

    1986-03-06

    A walk-through survey was conducted at Kendall Company, Augusta, Georgia in February, 1984. The purpose of the survey was to determine the feasibility of including the facility in a NIOSH industry wide mortality and industrial hygiene study of ethylene oxide. The company produces medical supplies such as gauze pads, sponges, cotton balls, and trays that ore sterilized with ethylene oxide.

  3. Encapsulation of Ethylene Gas into Granular Cold-Water-Soluble Starch: Structure and Release Kinetics.

    PubMed

    Shi, Linfan; Fu, Xiong; Tan, Chin Ping; Huang, Qiang; Zhang, Bin

    2017-03-15

    Ethylene gas was introduced into granular cold-water-soluble (GCWS) starches using a solid encapsulation method. The morphological and structural properties of the novel inclusion complexes (ICs) were characterized using scanning electron microscopy, X-ray diffractometry, and Raman spectroscopy. The V-type single helix of GCWS starches was formed through controlled gelatinization and ethanol precipitation and was approved to host ethylene gas. The controlled release characteristics of ICs were also investigated at various temperature and relative humidity conditions. Avrami's equation was fitted to understand the release kinetics and showed that the release of ethylene from the ICs was accelerated by increasing temperature or RH and was decelerated by increased degree of amylose polymerization. The IC of Hylon-7 had the highest ethylene concentration (31.8%, w/w) among the five starches, and the IC of normal potato starch showed the best controlled release characteristics. As a renewable and inexpensive material, GCWS starch is a desirable solid encapsulation matrix with potential in agricultural and food applications.

  4. 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.

  5. Asymmetric poly(ethylene-alt-propylene)-poly(ethylene oxide) micelles: a system with starlike morphology and interactions.

    PubMed

    Laurati, M; Stellbrink, J; Lund, R; Willner, L; Zaccarelli, E; Richter, D

    2007-10-01

    We report on an experimental study of single particle properties and interactions of poly(ethylene-alt-propylene)-poly(ethylene oxide) (PEP-PEO) starlike micelles. The starlike regime is achieved by an extremely asymmetric block ratio (1:20) and the number of arms (functionality) is changed by varying the composition of the solvent (the interfacial tension). Small angle neutron scattering (SANS) data in the dilute regime can be modeled by assuming a constant density profile in the micellar core (compact core) and a starlike density profile in the corona (starlike shell). The starlike morphology of the corona is confirmed by a direct comparison with SANS measurements of dilute poly butadiene star solutions. Comparison of structure factors obtained by SANS measurements in the concentrated regime shows in addition that the interactions in the two systems are equivalent. Micellar structure factors at several packing fractions can be modeled by using the ultrasoft potential recently proposed for star polymers [Likos, Phys. Rev. Lett. 80, 4450 (1998)]. The experimental phase diagram of PEP-PEO micelles is quantitatively compared to theoretical expectations, finding good agreement for the location of the liquid-solid boundary and excellent agreement for the critical packing fraction where the liquid-to-bcc crystal transition takes place for f<70. The functionality, i.e., the coronal density, strongly influences the nature of the solid phase: for f<70 the system crystallizes into a bcc phase, high f>70 formation of amorphous arrested states prevents crystallization.

  6. Analysis of Volatile Organic Compounds in a Controlled Environment: Ethylene Gas Measurement Studies on Radish

    NASA Technical Reports Server (NTRS)

    Kong, Suk Bin

    2001-01-01

    Volatile organic compound(VOC), ethylene gas, was characterized and quantified by GC/FID. 20-50 ppb levels were detected during the growth stages of radish. SPME could be a good analytical tool for the purpose. Low temperature trapping method using dry ice/diethyl ether and liquid nitrogen bath was recommended for the sampling process for GC/PID and GC/MS analysis.

  7. Theoretical investigation of the gas-phase reactions of CrO(+) with ethylene.

    PubMed

    Scupp, Thomas M; Dudley, Timothy J

    2010-01-21

    The potential energy surfaces associated with the reactions of chromium oxide cation (CrO(+)) with ethylene have been characterized using density functional, coupled-cluster, and multireference methods. Our calculations show that the most probable reaction involves the formation of acetaldehyde and Cr(+) via a hydride transfer involving the metal center. Our calculations support previous experimental hypotheses that a four-membered ring intermediate plays an important role in the reactivity of the system. We have also characterized a number of viable reaction pathways that lead to other products, including ethylene oxide. Due to the experimental observation that CrO(+) can activate carbon-carbon bonds, a reaction pathway involving C-C bond cleavage has also been characterized. Since many of the reactions involve a change in the spin state in going from reactants to products, locations of these spin surface crossings are presented and discussed. The applicability of methods based on Hartree-Fock orbitals is also discussed.

  8. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (2016 Interagency Science Discussion Draft)

    EPA Science Inventory

    In December 2016, EPA finalized its Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide. EPA’s evaluation was reviewed internally by EPA and by other federal agencies and White House Offices in October 2016, before public release. Consistent with the May 2009 IRIS asse...

  9. Mortality of workers exposed to ethylene oxide: extended follow up of a British cohort.

    PubMed

    Coggon, D; Harris, E C; Poole, J; Palmer, K T

    2004-04-01

    To obtain further information about the risks of cancer associated with occupational exposure to ethylene oxide Follow up was extended by 13 years for a cohort of 2876 men and women with definite or potential exposure to ethylene oxide in the chemical industry or in hospital sterilising units. Subjects were traced through National Health Service and social security records, and their mortality was compared with that expected from rates in the national population by the person-years method. Analysis was based on 565 deaths, of which 339 had occurred during the additional period of follow up. Mortality was close to or below expectation for all causes (565 deaths v 607.6 expected), all cancers (188 v 184.2), and for all specific categories of malignancy including stomach cancer (10 v 11.6), breast cancer (11 v 13.2), non-Hodgkin's lymphoma (7 v 4.8), and leukaemia (5 v 4.6). All five deaths from leukaemia occurred in the subset of subjects with greatest potential for exposure to ethylene oxide, but even in this group the excess of deaths was small (2.6 expected). The balance of evidence from this and other epidemiological investigations indicates that any risk of human cancer from ethylene oxide is low, particularly at the levels of occupational exposure that have occurred in Britain over recent decades. This may reflect the capacity of human cells to repair DNA damage caused by the chemical, which is a potent genotoxin and animal carcinogen.

  10. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (2011 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)...

  11. 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...

  12. 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...

  13. 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...

  14. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (2016 Interagency Science Discussion Draft)

    EPA Science Inventory

    In December 2016, EPA finalized its Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide. EPA’s evaluation was reviewed internally by EPA and by other federal agencies and White House Offices in October 2016, before public release. Consistent with the May 2009 IRIS asse...

  15. Will ethylene oxide sterilization influence the application of novel Cu/LDPE nanocomposite intrauterine devices?

    PubMed

    Xia, Xianping; Wang, Yun; Cai, Shuizhou; Xie, Changsheng; Zhu, Changhong

    2009-01-01

    Copper/low-density polyethylene (Cu/LDPE) nanocomposite intrauterine device (IUD) is an implanted medicinal device that must be sterilized before use. Sterilization processes act either chemically or physically, leading to a lethal change in the structure or function of organic macromolecules in microorganisms. Given the nature of their action, sterilization might also attack the macromolecules of polymers by the same mechanisms, resulting in changes in surface functional groups and in the internal structure of the polymer. If sterilization leads to changes in surface functional groups and in the internal structure of the LDPE matrix, which will influence the mechanical property and cupric ions release rate of novel Cu/LDPE nanocomposite IUDs, potential clinical application will be limited. Therefore, it is necessary to study the influence of ethylene oxide sterilization on the potential clinical application of novel Cu/LDPE nanocomposite IUDs. The influence of ethylene oxide sterilization on the internal structure, surface functional groups, mechanical property and cupric ions release rate of novel Cu/LDPE nanocomposite IUDs was studied using differential scanning calorimetry, attenuated total reflection Fourier transform infrared spectroscopy, tensile testing and absorbance measurement. Ethylene oxide sterilization did not have any influence on the internal structure, surface functional groups, mechanical property and cupric ions release rate of novel Cu/LDPE nanocomposite intrauterine devices. Ethylene oxide sterilization will not affect the potential application of novel Cu/LDPE nanocomposite IUDs.

  16. 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...

  17. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (2011 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)...

  18. 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 (P-91...

  19. 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 (P-91...

  20. 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 (P-91...

  1. 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.

  2. 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.

  3. [Determination of ethylene glycol in workplace air by capillary column gas chromatography].

    PubMed

    Li, Tiandi; Lin, Yiran; Zhang, Wen; He, Juntao

    2015-12-01

    To establish the method of capillary column gas chromatography for determination of ethylene glycol in workplace air. Ethylene glycol in workplace air was collected with silicone tube, desorbed with methanol, separated with FFAP (nitroterephthalic acid-modified polyethylene glycol)capillary column, and measured with flame ionization detector. The detection limit of ethylene glycol was 0.41 mg/L, the lower limit of quantification was 1.4 mg/L, the range of measurement was 1.4~163.9 mg/L, and the minimum detectable concentration was 0.3 mg/m3 (1.5 L of air was collected as the sample). This method had a good repeatability, the relative standard deviation was 1.4%~5.2%, the average desorption efficiency was 94.4%~101.7%, and the sampling efficiency was 99.2%~100%. The penetrating capacity of 200 mg silicone was higher than 6.9 mg, and the samples could be preserved for 14 days at room temperature. The method has a low detection limit, high accuracy, and good precision, which is feasible for determination of ethylene glycol in workplace air.

  4. 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.

  5. Toxicity potential of residual ethylene oxide on fresh or frozen embryos maintained in plastic straws.

    PubMed

    Schiewe, M C; Schmidt, P M; Pontbriand, D; Wildt, D E

    1988-01-01

    The toxic effects of residual ethylene oxide (EtO), a frequently used gas-sterilant, on embryos either frozen for long-term purposes or stored acutely for 30 min to 9 hr in a fresh condition in 0.25-ml straw containers were evaluated. In Experiment 1, fresh embryos were frozen (using conventional technology) in straws previously aerated for 0 hr to 8 mo after EtO sterilization. With the exception of the 8-mo group in which survival and quality ratings were depressed, embryo viability was not affected significantly by short-term prefreeze and post-thaw exposure to EtO residues. Experiment 2 was conducted to analyze the influence of prefreeze exposure to EtO residues on embryo development in vitro for embryos temporarily stored in previously sterilized straws aerated for different intervals. Compared to non-EtO-sterilized control straws, the development, quality, and viability of embryos exposed to EtO-treated straws were compromised (p less than 0.05) as the aeration interval decreased and the exposure interval increased. The combined results of both experiments indicate that EtO-treated straws can be used to cryopreserve gametes efficiently, but only if the aeration interval is greater than or equal to 72 hr and the prefreeze duration of exposure is less than or equal to 3 hr.

  6. Comparison of liquid chemical sterilization with peracetic acid and ethylene oxide sterilization for long narrow lumens.

    PubMed

    Alfa, M J; DeGagne, P; Olson, N; Hizon, R

    1998-10-01

    The aim of this study was to determine how well peracetic acid liquid chemical sterilization (LCPAS) killed test organisms in the presence of 10% fetal bovine serum and 0.65% salt challenge (RPMI-S) compared with a 100% ethylene oxide (ETO) sterilizer and an ETO hydrochlorofluorocarbon (ETO-HCFC) sterilization method with long (125 cm), narrow (3-mm internal diameter) flexible lumens as the test carrier. The inoculated lumens were dried overnight before processing. The test organisms included Mycobacterium chelonei, Enterococcus faecalis, and Bacillus subtilis. For all 3 organisms tested, the LCPAS process resulted in a 6 log10 reduction in bacterial load compared with a 2.5 log10 to 6 log10 reduction for the 100% ETO and ETO-HCFC sterilizers. Sterilization was achieved for 100%, 61%, and 67% of the lumen test carriers for the LCPAS, 100% ETO, and ETO-HCFC sterilizers, respectively. The data indicate that of the sterilization methods evaluated, LCPAS was the most effective for sterilizing narrow flexible lumens in the presence of residual inorganic and organic soil. This effectiveness was achieved through a combination of organism wash-off and peracetic acid sterilant killing of organisms. Salt was the major compounding factor for effective ETO gas sterilization, because carriers inoculated with organisms in 10% fetal bovine serum alone all were sterilized by both 100% ETO and ETO-HCFC sterilization methods. Our data support the critical need to ensure adequate precleaning of narrow flexible lumen endoscopes before any sterilization method.

  7. 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.

  8. 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.

  9. Ethylene Epoxidation at the Phase Transition of Copper Oxides.

    PubMed

    Greiner, Mark T; Jones, Travis E; Klyushin, Alexander; Knop-Gericke, Axel; Schlögl, Robert

    2017-08-30

    Catalytic materials tend to be metastable. When a material becomes metastable close to a thermodynamic phase transition it can exhibit unique catalytic behavior. Using in situ photoemission spectroscopy and online product analysis, we have found that close to the Cu2O-CuO phase transition there is a boost in activity for a kinetically driven reaction, ethylene epoxidation, giving rise to a 20-fold selectivity enhancement relative to the selectivity observed far from the phase transition. By tuning conditions toward low oxygen chemical potential, this metastable state and the resulting enhanced selectivity can be sustained. Using density functional theory, we find that metastable O precursors to the CuO phase can account for the selectivity enhancements near the phase transition.

  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. 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.

  12. PtIr-WO3 nanostructured alloy for electrocatalytic oxidation of ethylene glycol and ethanol.

    PubMed

    Murawska, Magdalena; Cox, James A; Miecznikowski, Krzysztof

    2014-01-01

    In this article, we characterized tungsten oxide-decorated carbon-supported PtIr nanoparticles and tested it for the electrooxidation reactions of ethylene glycol and ethanol. Phase and morphological evaluation of the proposed electrocatalytic materials are investigated employing various characterization techniques including X-ray diffraction (XRD) and transmission electron microscopy (TEM). Electrochemical diagnostic measurements such as cyclic voltammetry, chronoamperometry, and linear sweep voltammetry revealed that the tungsten oxide-modified PtIr/Vulcan nanoparticles have higher catalytic activity for ethylene glycol and ethanol electrooxidation than that of PtIr/Vulcan. A significant enhancement for electrooxidation of CO-adsorbate monolayers occurred in the presence of a transition metal oxide relative to that of pure PtIr/Vulcan electrocatalyst. The likely reasons for this are modification on the Pt center electronic structure and/or increasing the population of reactive oxo groups at the PtIr/Vulcan electrocatalytic interface in different potential regions.

  13. 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

    2009-07-08

    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.

  14. A sensitive estimation of residual ethylene glycol in ethylene oxide sterilized medical devices by HPLC with electrospray ionization mass spectrometric detection.

    PubMed

    Hari, P R; Naseerali, C P; Sreenivasan, K

    2009-01-15

    A novel analytical methodology for the estimation of residual ethylene glycol (EG) in ethylene oxide sterilized polymer is reported. The method involves the monitoring of ammonium adduct of EG ions in the presence of 10 mM ammonium acetate buffer and methanol using electrospray ionization liquid chromatography and mass spectrometry (LC-ESI-MS). The method enables the detection and quantification of EG without prior derivatization up to a level of 0.06 microg/ml. The potentiality of the method is demonstrated by estimating EG in ethylene oxide (EtO) sterilized polyethylene terephthalate fabric used in heart valve sewing ring. The method is simple, rapid and can routinely be used for the quantification of residual EG in EtO sterilized medical devices.

  15. Tuning ethylene gas adsorption via metal node modulation: Cu-MOF-74 for a high ethylene deliverable capacity.

    PubMed

    Liao, Yijun; Zhang, Lin; Weston, Mitchell H; Morris, William; Hupp, Joseph T; Farha, Omar K

    2017-08-17

    M-MOF-74s were examined for potential applications in ethylene abatement and/or storage/delivery. Due to labile binding resulting from a Jahn-Teller distortion, Cu-MOF-74 exhibits a gradual initial uptake that, in turn, translates into the highest deliverable capacity among the MOFs examined (3.6 mmol g(-1)). In contrast, Co-MOF-74 is the most promising candidate for ethylene abatement due to the sharp uptake at low pressure.

  16. Ethylene and nitric oxide interact to regulate the magnesium deficiency-induced root hair development in Arabidopsis.

    PubMed

    Liu, Miao; Liu, Xing Xing; He, Xiao Lin; Liu, Li Juan; Wu, Hao; Tang, Cai Xian; Zhang, Yong Song; Jin, Chong Wei

    2017-02-01

    Nitric oxide (NO) and ethylene respond to biotic and abiotic stresses through either similar or independent processes. This study examines the mechanism underlying the effects of NO and ethylene on promoting root hair development in Arabidopsis under magnesium (Mg) deficiency. The interaction between NO and ethylene in the regulation of Mg deficiency-induced root hair development was investigated using NO- and ethylene-related mutants and pharmacological methods. Mg deficiency triggered a burst of NO and ethylene, accompanied by a stimulated development of root hairs. Interestingly, ethylene facilitated NO generation by activation of both nitrate reductase and nitric oxide synthase-like (NOS-L) in the roots of Mg-deficient plants. In turn, NO enhanced ethylene synthesis through stimulating the activities of 1-aminocyclopropane-1-carboxylate (ACC) oxidase and ACC synthase (ACS). These two processes constituted an NO-ethylene feedback loop. Blocking either of these two processes inhibited the stimulation of root hair development under Mg deficiency. In conclusion, we suggest that Mg deficiency increases the production of NO and ethylene in roots, each influencing the accumulation and role of the other, and thus these two signals interactively regulate Mg deficiency-induced root hair morphogenesis. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  17. 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

    2016-03-18

    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.

  18. Carbon isotope fractionation during permanganate oxidation of chlorinated ethylenes (cDCE, TCE, PCE).

    PubMed

    Poulson, Simon R; Naraoka, Hiroshi

    2002-08-01

    Permanganate oxidation of chlorinated ethylenes is an attractive technique to effect remediation of these important groundwater contaminants. Stable carbon isotope fractionation associated with permanganate oxidation of trichloroethylene (TCE), tetrachloroethylene (PCE), and cis-1,2-dichloroethylene (cDCE) has been measured, to study the possibility of applying stable carbon isotope analysis as a technique to assess the efficacy of remediation implemented by permanganate oxidation. Average carbon isotope fractionation factors of alphaTCE = 0.9786, alphaPCE = 0.9830, and alphacDCE = 0.9789 were obtained, although the fractionation factor for PCE may be interpreted to change from a value of 0.9779-0.9871 during the course of the reaction. The fractionation factors for all three compounds are quite similar, in contrast to the variation of fractionation factors vs degree of chlorination observed for other degradative processes, such as microbial dechlorination. This may be due to a common rate-determining step for permanganate oxidation of all three compounds studied. The large fractionation factors and the relative lack of dependence of the fractionation factors upon other environmental factors (e.g. oxidation rate, presence of multiple contaminants, incomplete oxidation, presence of chloride in solution) indicate that monitoring delta13C values of chlorinated ethylenes during oxidation with permanganate may be a sensitive, and potentially quantitative, technique to investigate the extent of degradation.

  19. Photoionization and ion cyclotron resonance studies of the ion chemistry of ethylene oxide

    NASA Technical Reports Server (NTRS)

    Corderman, R. R.; Williamson, A. D.; Lebreton, P. R.; Buttrill, S. E., Jr.; Beauchamp, J. L.

    1976-01-01

    The formation of the ethylene oxide molecular ion and its subsequent ion-molecule reactions leading to the products C2H5O(+) and C3H5O(+) have been studied using time-resolved photoionization mass spectroscopy, ion cyclotron resonance spectroscopy, and photoelectron spectroscopy. An examination of the effects of internal energy on reactivity shows that the ratio of C3H5O(+) to C2H5O(+) increases by an order of magnitude with a single quantum of vibrational energy. The formation of (C2H4O/+/)-asterisk in a collision-induced isomerization is found which yields a ring-opened structure by C-C bond cleavage. The relaxed ring-opened C2H4O(+) ion reacts with neutral ethylene oxide by CH2(+) transfer to yield an intermediate product ion C3H6O(+) which gives C3H5O(+) by loss of H.

  20. Problems associated with sterilization using ethylene oxide. Residues in treated materials.

    PubMed

    Buben, I; Melichercíková, V; Novotná, N; Svitáková, R

    1999-11-01

    The paper deals with problems associated with reduction of undesirable effects of ethylene oxide in polymers in medical devices on the patient's health. The authors explain the need of careful elaboration and validation of the sterilization and aeration process incl assessment of ethylene oxide (EO) residues. The authors investigated the effect of the type of material and conditions of sterilization and aeration on the assessed EO concentration. For research of the behaviour of different polymers in the sterilization process model sterilizations of actual items of medical devices with a known composition proved more suitable than assessment in medical devices from medical institutions. The main conclusions of the investigation were a classification of polymers into those suitable and unsuitable for sterilization or resterilization, and attention was also drawn to poor reproducibility of results in old sterilizers, in particular those lacking effective aeration in aerators.

  1. 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.

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

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

  4. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (Revised August 2014 External Review Draft) (SAB 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.

  5. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (Revised August 2014 External Review Draft) (SAB 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.

  6. Thermal stability of polyacetal/ethylene-octene copolymer/zinc oxide nanocomposites

    NASA Astrophysics Data System (ADS)

    Grigalovica, A.; Merijs Meri, R.; Zicans, J.; Ivanova, T.; Grabis, J.

    2013-12-01

    In this work we investigate binary blends of polyoxymethylene and ethylene octene copolymer (EOC) and their composites with nanostructured zinc oxide (ZnO). EOC content in the composites varies from 0 to 50 wt. %. The amount of ZnO filler in the composites is changed in the interval from 0 to 5 wt. %. Thermal properties of composites are investigated with thermogravimetric analysis and differential scanning calorimetry. It is observed that ZnO addition increases thermal stability of the investigated composites.

  7. 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

  8. The effect of repeated ethylene oxide sterilization on the mechanical strength of synthetic absorbable sutures.

    PubMed

    Woods, T O; Brown, S A; Merritt, K; McNamee, S G; Hitchins, V M

    2001-01-01

    The purpose of this study was to determine the effect of repeated ethylene oxide sterilization using a standard clinical protocol on sutures, a type of medical device labeled for single use and reported to be reprocessed for use after being opened but not used. Four types of commonly used synthetic absorbable sutures were subjected to 1 and 2 ethylene oxide resterilization cycles. Knot tensile strength was determined for new sutures and for sutures that had been subjected to 1 and 2 ethylene oxide resterilization cycles. As has been found with other types of single-use devices, no general conclusions can be made for absorbable sutures. The strengths of different types of sutures increased, decreased, or stayed the same after repeated sterilization. In addition, the inner packages of some sutures were not intact after reprocessing, possibly exposing the sutures to increased humidity, which can produce degradation leading to loss of strength both immediately and after additional shelf aging and degraded performance after clinical use.

  9. Reduction of PCR-amplifiable DNA by ethylene oxide treatment of forensic consumables.

    PubMed

    Neureuther, Katharina; Rohmann, Edyta; Hilken, Manuela; Sonntag, Marie-Luise; Herdt, Silke; Koennecke, Thomas; Jacobs, Roland; Adamski, Michalina; Reisbacher, Stefan; Alfs, Knut; Strain, Peter; Bastisch, Ingo

    2014-09-01

    A reliable method to provide molecular biology products free of contaminating DNA is of forensic interest. Ethylene oxide (EO) treatment has been demonstrated as an effective method in published studies. This study aimed to address some additional experiments that are closer to forensic practice. In the first part of this study, different consumables such as cotton swabs, latex gloves and micro test tubes were spiked with saliva, blood and skin cells to mimic a real-life contamination scenario. EO treatment was performed for a period of 3, 5, 7, and 10h, respectively. For comparison, gamma and electron beam treatment was applied. In the second part of this study, a cell culture line (K562) was used to apply defined cell counts on cotton swabs followed by EO treatment for 3 and 5h. After extraction of samples, the DNA content was quantified using a real-time PCR based system. STR analysis was performed using a latest generation STR kit to meet current sensitivity limits. A good correlation of real-time PCR results and STR results was observed. This work confirmed the findings of earlier studies showing that chemical EO treatment is much more successful in reducing the amount of PCR-amplifiable DNA than ionising radiation. Furthermore, the efficacy of EO treatment is affected by the nature of the samples. DNA in saliva was more susceptible to damage by EO gas than DNA in blood. Our results show, that accessibility of the sample to EO gas has a strong influence on the method's efficiency. While treatment of samples on cotton swabs packed into gas-permeable bags was very successful, samples inside a closed micro test tube were resistant to the same treatment conditions. Our work with defined K562 cell numbers and multi-copy quantitative PCR could show that a 5h EO treatment results in a 10(5) fold reduction of PCR-amplifiable DNA. Corresponding STR-PCR results also show only sporadic allele calls in the Mini-loci range, providing a reliable interpretation of forensic

  10. Ethylene oxide and breast cancer incidence in a cohort study of 7576 women (United States).

    PubMed

    Steenland, Kyle; Whelan, Elizabeth; Deddens, James; Stayner, Leslie; Ward, Elizabeth

    2003-08-01

    Ethylene oxide (ETO) is a sterilant gas considered to be a human carcinogen, due primarily to excess hematopoietic cancer in exposed cohorts. ETO causes mammary tumors in mice, and has been associated with breast cancer incidence in one small epidemiologic study. We have studied breast cancer incidence in a cohort of 7576 women employed for at least one year and exposed for an average 10.7 years while working in commercial sterilization facilities. Breast cancer incidence (n = 319) was ascertained via interview, death certificates, cancer registries, and medical records. Interviews were obtained for 68% of the cohort. The standardized incidence ratio (SIR) for incident breast cancer in the whole cohort using external referent rates (SEER) was 0.87 (0.77-0.97). The SIR for those in the top quintile of cumulative exposure, with a 15 year lag, was 1.27 (0.94-1.69), with a positive trend of increasing SIR with increasing exposure (p = 0.002). SIRs are underestimated because breast cancer incidence in the whole cohort was under-ascertained, due to incomplete response and lack of complete coverage by state cancer registries. In internal nested case-control analyses of those with interviews (complete cancer ascertainment), controlling for reproductive risk factors, a positive exposure-response was found with the log of cumulative exposure with a 15-year lag (p = 0.0005). The odds ratio by quintile of cumulative exposure were 1.00 (0 exposure due to 15 year lag), 1.06, 0.99, 1.24, 1.42, and 1.87. Our data suggest that ETO is associated with breast cancer, but a causal interpretation is weakened due to some inconsistencies in exposure-response trends and possible biases due to non-response and incomplete cancer ascertainment.

  11. Dose-rate effects of ethylene oxide exposure on developmental toxicity.

    PubMed

    Weller, E; Long, N; Smith, A; Williams, P; Ravi, S; Gill, J; Henessey, R; Skornik, W; Brain, J; Kimmel, C; Kimmel, G; Holmes, L; Ryan, L

    1999-08-01

    In risk assessment, evaluating a health effect at a duration of exposure that is untested involves assuming that equivalent multiples of concentration (C) and duration (T) of exposure have the same effect. The limitations of this approach (attributed to F. Haber, Zur Geschichte des Gaskrieges [On the history of gas warfare], in Funf Vortrage aus den Jahren 1920-1923 [Five lectures from the years 1920-1923], 1924, Springer, Berlin, pp. 76-92), have been noted in several studies. The study presented in this paper was designed to specifically look at dose-rate (C x T) effects, and it forms an ideal case study to implement statistical models and to examine the statistical issues in risk assessment. Pregnant female C57BL/6J mice were exposed, on gestational day 7, to ethylene oxide (EtO) via inhalation for 1.5, 3, or 6 h at exposures that result in C x T multiples of 2100 or 2700 ppm-h. EtO was selected because of its short half-life, documented developmental toxicity, and relevance to exposures that occur in occupational settings. Concurrent experiments were run with animals exposed to air for similar periods. Statistical analysis using models developed to assess dose-rate effects revealed significant effects with respect to fetal death and resorptions, malformations, crown-to-rump length, and fetal weight. Animals exposed to short, high exposures of EtO on day 7 of gestation were found to have more adverse effects than animals exposed to the same C x T multiple but at longer, lower exposures. The implication for risk assessment is that applying Haber's Law could potentially lead to an underestimation of risk at a shorter duration of exposure and an overestimation of risk at a longer duration of exposure. Further research, toxicological and statistical, are required to understand the mechanism of the dose-rate effects, and how to incorporate the mechanistic information into the risk assessment decision process.

  12. Enhancement of the kinetics of the aeration of ethylene oxide sterilized polymers using microwave radiation.

    PubMed

    Matthews, I P; Gibson, C; Samuel, A H

    1989-02-01

    Ethylene oxide (EO) is used extensively to sterilize medical supplies that are heat sensitive. EO residues in materials post sterilization can present a hazard to patients at the point of use. Protracted aeration (i.e. degassing) times are necessary post sterilization to reduce EO residues to an accepted level. The sorption of EO into polyvinylchloride was found to be an active process given that at sorption equilibrium (i.e. when the net flow of diffusant into the host material has reduced to zero) the number of molecules of EO per unit volume was greater in PVC than in its external environment. The diffusion coefficient (D) was concentration (c) dependent and the relationship which best describes this dependence was D(c) alpha ln c. The diffusion of EO was dramatically accelerated (as evidenced by a time saving in degassing of up to 400%) if microwave heating (2.45 GHz) was used instead of conventional heating for the same macroscopic temperature. The values of activation energy for diffusion were obtained from the respective Arrhenius plots of diffusion coefficient versus inverse temperature for each process. In general, even small reductions in activation energy can greatly increase the specific rate of reaction. The relative efficacy of microwaves in eliminating EO residues as evidenced by this data occurs as a result of microwaves reducing the activation energy for diffusion by almost a factor of two. The relative efficiency of microwave desorption compared to conventional aeration offers considerable gains in the cost-effectiveness of gas sterilization since it will permit a much greater throughput of material, thereby obviating the need for excessively large inventories of equipment.

  13. Effects of ethylene oxide resterilization and in-vitro degradation on mechanical properties of partially absorbable composite hernia meshes.

    PubMed

    Endogan, T; Ozyaylali, I; Kulacoglu, H; Serbetci, K; Kiyak, G; Hasirci, N

    2013-01-01

    Prosthetic mesh repair for abdominal wall hernias is widely used because of its technical simplicity and low hernia recurrence rates. The most commonly used material is pure polypropylene mesh, although newer composite materials are recommended by some centers due to their advantages.However, these meshes are more expensive than pure polypropylene meshes. Resterilization of a pure polypropylene mesh has been shown to be quite safe, and many centers prefer slicing a large mesh into smaller pieces, suitable for any hernia type or defect size. Nevertheless there is no data about the safety after resterilization of the composite meshes. The present study was carried out to investigate the effects of resterilization and in vitro degradation in phosphate buffered saline solution on the physical structure and the mechanical properties of partially absorbable lightweight meshes. Two composite meshes were used in the study: One mesh consists of monofilament polypropylene and monofilament polyglecaprone -a copolymer of glycolide and epsilon(ε)- caprolactone - (Ultrapro®, 28 g m2, Ethicon, Hamburg,Germany), and the other one consisted of multifilament polypropylene and multifilament polyglactine (Vypro II®, 30g m2, Ethicon, Hamburg, Germany). Two large meshes were cut into rectangular specimens sized 50 x 20 mm for mechanical testing and 20 x 20 mm for in vitro degradation experiments.Meshes were divided into control group with no resterilization and gas resterilization. Ethylene oxide gas sterilization was performed at 55°C for 4.5 hours. In vitro degradation in 0.01M phosphate buffered saline (PBS, pH 7.4) solution at 37 ± 1°C for 8 weeks was applied to one subgroup in each mesh group. Tensiometric measurements and scanning electronmicroscopic evaluations were completed for control and resterilization specimens. Regardless of resterilization, when the meshes were exposed to in vitro degradation, all mechanical parameters decreased significantly. Highest reduction in

  14. EFFECTS OF ETHYLENE OXIDE RESTERILISATION AND IN-VITRO DEGRADATION ON MECHANICAL PROPERTIES OF PARTIALLY ABSORBABLE COMPOSITE HERNIA MESHES.

    PubMed

    Endogan, T; Ozyaylali, I; Kulacoglu, H; Serbetci, K; Kiyak, G; Hasirci, N

    2013-06-01

    Prosthetic mesh repair for abdominal wall hernias is widely used because of its technical simplicity and low hernia recurrence rates. The most commonly used material is pure polypropylene mesh, however newer composite materials are recommended by some centers because of their advantages. However, these meshes are more expensive than pure polypropylene meshes. Resterilisation of a pure polypropylene mesh has been shown to be quite safe, and many centers prefer slicing a large mesh into smaller pieces that suitable for hernia type or defect size. Nevertheless there is no data about the safety after resterilisation of the composite meshes. To search the effects of resterilisation and In vitro degradation in phosphate buffered saline solution on the physical structure and the mechanical properties of partially absorbable lightweigth meshes. Laboratory-based research. Two composite meshes were used in the study: One mesh is consisted of monofilament polypropylene and monofilament polyglecaprone--a copolymer of glycolide and epsilon (ε)-caprolactone--(Ultrapro®, 28 g/m2, Ethicon, Hamburg, Germany),andthe otherone consisted of multifilamentpolypropyleneandmultifilament polyglactine (Vypro II®, 30 g/m2,Ethicon, Hamburg, Germany). Two large meshes were cut into rectangular specimens sized 50x20 mm for mechanical testing and 20x20 mm for In vitro degradation experiments. Meshes were divided into control group with no resterilisation and gas resterilisation. Ethylene oxide gas sterilisation was performed at 55°C for 4.5 hours. In vitro degradation in 0.01 M phosphate buffered saline (PBS, pH 7.4) solution at 37 ± 1°C for 8 weeks was applied to one subgroup in each mesh group. Tensiometric measurements and scanning electron microscopyic evaluations were completed for control and resterilisation specimens. Regardless of resterilisation, when meshes were exposed to In vitro degradation, all mechanical parameters decreased significantly. Highest reduction in mechanical

  15. [Toxicity of ethylene oxide on the crystalline lense in an occupational milieu. Difficulty of epidemiologic surveys of cataract].

    PubMed

    Deschamps, D; Leport, M; Cordier, S; Laurent, A M; Festy, B; Hamard, H; Renard, G; Pouliquen, Y; Conso, F

    1990-01-01

    Ethylene oxide is a sterilizing gas for heat-sensitive materials. Eight cases of subcapsular cataract were attributed to this compound from 1982 to 1985. This epidemiological study was conducted in 55 persons to determine the prevalence of lens opacities and cataracts in workers exposed to this gas. The 21 persons of more than 45 years of age were then compared to 16 non-exposed persons matched for age and gender. Lens opacities (independently of visual acuity) were observed in 19 of the 55 exposed. Among exposed and non-exposed persons of more than 45 years of age, there were no significantly differences with regard to the following characteristics of lens opacities: prevalence (13 in the 21 exposed; 10 in the 16 non-exposed), distribution of the localisations, morphology and importance of the cortical opacities. No link was found between the characteristics of the lens opacities and the characteristics of the exposure: habitual exposure and accidental overexposures. For cataracts, defined by the association of lens opacities and a visual acuity less than 20/25 (this loss not being attributable to another cause), their prevalence differed significantly (p less than 0.05) between the exposed (6 of 21) and the non-exposed (0 of 16). There was no relation between their existence and accidental overexposures. The risk of lens opacification by ethylene oxide, established in cases of massive exposures as previously described, could also exist during chronic exposure to low concentrations, but is to be confirmed by other studies. It could be explained by saturation of the protective mechanisms against alkylating action of this product. This study prompted us to discuss the epidemiological difficulties in studies of cataracts.

  16. Involvement of ethylene and nitric oxide in cell death in mastoparan-treated unicellular alga Chlamydomonas reinhardtii.

    PubMed

    Yordanova, Zhenya P; Iakimova, Elena T; Cristescu, Simona M; Harren, Frans J M; Kapchina-Toteva, Veneta M; Woltering, Ernst J

    2010-02-22

    This work demonstrates a contribution of ethylene and NO (nitric oxide) in MP (mastoparan)-induced cell death in the green algae Chlamydomonas reinhardtii. Following MP treatment, C. reinhardtii showed massive cell death, expressing morphological features of PCD (programmed cell death). A pharmacological approach involving combined treatments with MP and ethylene- and NO-interacting compounds indicated the requirement of trace amounts of both ethylene and NO in MP-induced cell death. By employing a carbon dioxide laser-based photoacoustic detector to measure ethylene and a QCL (quantum cascade laser)-based spectrometer for NO detection, simultaneous increases in the production of both ethylene and NO were observed following MP application. Our results show a tight regulation of the levels of both signalling molecules in which ethylene stimulates NO production and NO stimulates ethylene production. This suggests that, in conjunction with the elicitor, NO and ethylene cooperate and act synchronously in the mediation of MP-induced PCD in C. reinhardtii. To the best of our knowledge, this is the first report on the functional significance of ethylene and NO in MP-induced cell death.

  17. Biologic markers in hospital workers exposed to low levels of ethylene oxide.

    PubMed

    Schulte, P A; Boeniger, M; Walker, J T; Schober, S E; Pereira, M A; Gulati, D K; Wojciechowski, J P; Garza, A; Froelich, R; Strauss, G

    1992-04-01

    Operators of hospital sterilizers that use ethylene oxide were studied to determine if there was a relationship between exposure and a battery of biological markers. A total of 73 workers from nine hospitals in the United States (U.S.) and one hospital in Mexico City was evaluated for ethylene oxide exposure during four months prior to collection of peripheral blood. The frequency of hemoglobin adducts (p = 0.0006) and sister-chromatid exchanges (SCEs) (p = 0.002) increased with cumulative exposure to ethylene oxide in U.S. subjects when controlling by regression analysis for various confounding factors, including cigarette smoking. Hemoglobin adducts, but not SCEs, were also increased in Mexican subjects (p = 0.0012). Chromosomal micronuclei showed no consistent relationship with exposure. The U.S. study participants were classified by four-month cumulative exposure levels of 10 ppm-h (n = 8), greater than 0 to 32 ppm-h (n = 32) and greater than 32 ppm-h (n = 11) of ethylene oxide exposure. The group with an exposure of greater than 32 ppm-h had an increased frequency of hemoglobin adducts (p = 0.002) and SCEs (p = 0.0001) compared to the nonexposed group. The estimated mean of the 8-h time-weighted average (8-h TWA) exposure levels for the highest U.S. exposure group (greater than 32 ppm-h) was 0.16 +/- 0.007 ppm (mean +/- SD). A similar exposure-related differential was observed in the Mexican subjects for hemoglobin adducts (p = 0.04) but not for SCEs. The latter finding may have been due to longer shipping times for the specimens in the cytogenetic assays. The estimated mean of the 8-h TWA exposure levels for the highest Mexican exposure group (greater than 32 ppm-h) was 0.48 +/- 0.08 ppm. This study is the third to suggest that exposures less than the U.S. OSHA standard of 1 ppm 8-h TWA result in biochemical and biologic changes. It is not known whether these changes may be indicative of increased risk of disease; however, they do appear to reflect exposure

  18. Breaking the apple embryo dormancy by nitric oxide involves the stimulation of ethylene production.

    PubMed

    Gniazdowska, Agnieszka; Dobrzyńska, Urszula; Babańczyk, Tomasz; Bogatek, Renata

    2007-03-01

    Mature seeds of apple (Mallus domestica Borb. cv. Antonówka) are dormant and do not germinate unless their dormancy is removed by several weeks of moist-cold treatment. We investigated the effect of short-term (3 h) nitric oxide (NO) pretreatment on breaking of apple embryonic dormancy expressed as inhibition of germination and morphological abnormalities of young seedlings. Imbibition of embryos isolated from dormant apple seeds with sodium nitroprusside (SNP) or S-nitroso,N-acetyl penicillamine (SNAP) as NO donors resulted in enhanced germination. Moreover, NO treatment removed morphological abnormalities of seedlings developing from dormant embryo. The NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-teramethylimidazoline-1-oxyl-3 oxide (cPTIO) removed the above effects. NO-mediated breaking of embryonic dormancy correlated well with enhanced ethylene production. Inhibitor of ethylene synthesis (AOA) reversed the stimulatory effect of NO donors on embryo germination. Additionally SNP reduced embryo sensitivity to exogenously applied ABA ensuing dormancy breakage. We can conclude that NO acts as a regulatory factor included in the control of apple embryonic dormancy breakage by stimulation of ethylene biosynthesis.

  19. Li + conducting 'fuzzy' poly(ethylene oxide)-SiO 2 polymer composite electrolytes

    NASA Astrophysics Data System (ADS)

    Zhang, S.; Lee, Jim Y.; Hong, L.

    Short and 'fuzzy' poly(ethylene) glycol chains with different molecule weights have been successfully grafted on to a pristine SiO 2 nanoparticle surface using toluene 2,4-diisocyanate as the bridging molecule. Solvent-free composite electrolytes based on poly(ethylene oxide), LiBF 4 and SiO 2 or modified SiO 2 particles have been prepared and compared. Composite electrolytes with modified SiO 2 show a noticeably smoother surface texture under scanning electron microscopy. This is attributed to improved compatibility between the ceramic particles and polymer. The increased amorphization of the polymer leads to increase in room-temperature ionic conductivity as more ion-conduction channels are created in close proximity to the modified silica particles. On the other hand, a lower transference number is the result of weakened Lewis acid-base interactions between the polymer backbone and a smaller number of OH groups on the silica surface.

  20. 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

  1. Polystyrene nanoparticles in the presence of (ethylene oxide)13(propylene oxide)30(ethylene oxide)13, N,N-dimethyloctylamine-N-oxide and their mixtures. A calorimetric and dynamic light scattering study.

    PubMed

    De Lisi, R; Lazzara, G; Milioto, S; Muratore, N

    2008-02-14

    Polystyrene nanoparticles were synthesized by emulsion polymerization of styrene. They were functionalized using the conventional surfactant N,N-dimethyloctylamine-N-oxide (ODAO), the tri-block copolymer (ethylene oxide)(13)(propylene oxide)(30)(ethylene oxide)(13) (L64) and their mixtures. To this purpose, dynamic light scattering and calorimetric experiments were carried out and provided information consistent to each other. The L64 adsorption is Langmuir-type in the copolymer dilute regime and generates complex structures at larger concentrations. In the region where ODAO is in the unimeric state, the adsorption process is cooperative leading to hemi-micelle formation at the polystyrene nanoparticle/water interface. In the concentrated region (above the critical micellar concentration), ODAO forms micelles which interact with the solid substrate most likely through ion-dipole forces. The ODAO addition to the dispersion containing polystyrene particles already wrapped by L64 creates an ODAO thickness around the dispersed particles the size of which is equal to that in the absence of the copolymer, but is built at much lower concentrations. A plausible interpretation of this behavior is that the adsorbed L64 confers to the nanoparticles surface novel properties which enhance the attractive forces with the ODAO molecules.

  2. Genotoxic risk for humans due to work place exposure to ethylene oxide: remarkable individual differences in susceptibility.

    PubMed

    Fuchs, J; Wullenweber, U; Hengstler, J G; Bienfait, H G; Hiltl, G; Oesch, F

    1994-01-01

    Single strand breaks of DNA of peripheral mononuclear blood cells from 97 male and female workers occupationally exposed to ethylene oxide were analysed by the alkaline elution method. These individuals were occupied with the sterilization of medical devices in hospitals and in commercial plants. Ethylene oxide in the air of the working areas was detected up to a maximal concentration of 16.5 mg/m3 calculated as 4-h time-weighted average (4h TWA). Mean value was 1.47 +/- 0.52 mg/m3 (1 mg/m3 = 0.55 ppm). Compared to the mean elution rate of the DNA from non-smoking workers exposed to air concentrations of ethylene oxide below the detection limit of 0.1 mg/m3 (4h TWA) the non-smokers working in rooms with a concentration of ethylene oxide between 0.5 mg/m3 and 2 mg/m3 showed a statistically significant (P < 0.05) 119% higher mean elution rate and even for the non-smokers exposed to 0.1-0.5 mg/m3 of ethylene oxide a statistically significant (P < 0.05) 53% higher mean elution rate was observed. For smokers a similar tendency was found but the increase in elution rates in response to the external exposure was smaller than in non-smokers and no statistical significance was obtained. According to their sensitivity to ethylene oxide the non-smoking workers could be classified into two subpopulations. In the majority of the non-smokers (67%) approximately 5-fold more DNA strand breaks were induced by ethylene oxide than in the other non-smokers. A lowest detectable effect level could only be specified for non-smokers. (ABSTRACT TRUNCATED AT 250 WORDS)

  3. Assessment of cancer risk from ethylene oxide residues in spices imported into New Zealand.

    PubMed

    Fowles, J; Mitchell, J; McGrath, H

    2001-11-01

    Quantitative estimates of cancer risks from ethylene oxide (ETO) residues were constructed based on 200 retail samples of various spices in New Zealand. Two samples of cinnamon contained detectable ETO. The highest value encountered was 15 ppm. ETO was not detected in the remaining 198 samples. However, 31 samples had detectable levels of ethylene chlorohydrin (ECH) and/or ethylene bromohydrin (EBH). A conservative estimate of ETO intake, based on average spice consumption, was 3.4 x 10(-6) mg/kg/day. Cancer potency factors for ETO ranging from 0.29 to 0.55 (mg/kg/day)(-1) were used to form cancer risk estimates. The resulting estimates of average lifetime excess cancer risk was 0.8 x 10(-6) to 1.7 x 10(-6). The US 97.5 percentile value for spice consumption (2.8 kg spices per year), gave an extreme upper-end estimate of lifetime cancer risk of approximately 1.4 x 10(-5). These risks are practically negligible considering the conservative assumptions used in estimating exposure to ETO. The exposures to ECH and EBH are 200-300-fold higher than to ETO. These compounds are of lesser potency to ETO in terms of mutagenicity or carcinogenicity in studies to date. However, the precise contribution of these compounds to the cancer risk estimate is uncertain due to large toxicological data gaps, including the absence of a 2-year cancer bioassay by the oral route.

  4. [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.

  5. Relationship between dose in vivo of ethylene oxide and exposure to ethene studied in exposed workers.

    PubMed

    Granath, F; Rohlén, O; Göransson, C; Hansson, L; Magnusson, A L; Törnqvist, M

    1996-10-01

    1. In vivo doses of ethylene oxide, arising from ethene exposure, in plastic industry workers were estimated through hemoglobin adducts. The ethene exposure was assessed through person-worn monitors. The metabolic conversion of ethene to ethylene oxide was estimated from the exposure dose/in vivo dose ratio. 2. Two studies were done: In the first study hemoglobin adducts were determined in samples collected on one occasion in exposed groups and exposure doses were estimated by using exposure data from the hygienic surveillance program. The second study applies a newly developed study design with repeated blood sampling in a few persons combined with a complete personal exposure monitoring during the study period. This makes it possible to relate adduct formation with individual short-time exposure doses, which in theory should overcome the problems with exposure history dependence of the adduct level in a single blood sample. The results of the second study shows that it is possible, through the proposed method, to utilize occupational exposure situations for this kind of studies even if the exposure pattern is irregular and highly variable. Both studies show a metabolic conversion of ethene to ethylene oxide of only 0.5%, which is unexpectedly low. 3. The cancer risk associated with the ethene exposure in the highly exposed group (3.6 p.p.m. 40 h/week) is estimated by applying the radiation-dose-equivalence approach. The result of this evaluation leads to a risk corresponding to a radiation dose of 4 mSv/year which is about a factor 3 below the current dose limit for radiological work recommended by ICRP.

  6. Hematological changes in hospital workers due to chronic exposure to low levels of ethylene oxide.

    PubMed

    Shaham, J; Levi, Z; Gurvich, R; Shain, R; Ribak, J

    2000-08-01

    We conducted a cross-sectional study to determine whether occupational exposure to low levels of ethylene oxide can cause hematological abnormalities. Blood samples were collected from a group of 47 hospital workers who were exposed to ethylene oxide during a mean period of 6.6 years (standard error, 1.1). Ethylene oxide range levels measured were < 0.01 to 0.06 ppm. The control group, individually matched by age, sex, and smoking habits, consisted of 88 workers from the administrative sector. We found significant differences between the exposed and the control group in the frequency of workers with white blood cells lower than the normal range. Although there was no significant difference in the absolute mean number of the total white blood cells, we found an elevation in the absolute mean number of monocytes and eosinophils (P < 0.01) and a decrease (P < 0.01) in the absolute mean number of lymphocytes in the exposed group compared with the control group. We also found an elevation (P < 0.01) in the percentage of hematocrit and the mean absolute number of the red blood cells, and a decrease (P < 0.01) in the mean absolute number of platelets, in the exposed group compared with the control group. The mean absolute number of eosinophils, red blood cells, and percentage of hematocrit was significantly higher, and the mean absolute number of lymphocytes and platelets was significantly lower, in the subgroups with a higher cumulative dose of exposure. A positive dose-response was found between cumulative dose exposure and the absolute mean number of eosinophils. In view of our findings, we suggest that the use of complete blood cells with differential in routine medical surveillance and for early detection of hygiene problems should be reexamined with special attention to the eosinophils count.

  7. Ignition delay times in ethylene oxide-oxygen-argon mixtures behind a reflected shock

    SciTech Connect

    Yoon, Hyun-mo; Yeo, Hwan-gon; Yun, Suck Sung; Kim, Chang-sik; Kang, Jun-Gill )

    1993-03-01

    A great deal of work has been conducted on the ignition delay times of fuel-oxygen-argon mixtures in shock tubes to investigate the complex combustion processes. Recently, the authors have studied the ignition behavior of nitromethane-oxygen-argon mixtures in the region behind a reflected shock wave. It was found that increasing concentrations of CH[sub 3]NO[sub 2] inhibits detonation and that the role of O[sub 2] as a detonation promoter is reduced in the reaction of the nitromethane mixture. This result could be due to the substituted NO[sub 2] group. The present study was undertaken to investigate the kinetics of the ethylene oxide combustion process. A single-pulse shock tube with 24.3 mm i.d. was used in this study. The shock speed was measured with two Kistler 6031 pressure transducers: one was mounted at a distance of 0.233 m from the other which was flush with the inside wall of the end plate. A detailed description of the experimental apparatus has been presented in previous work. The test gases were prepared by mixing vaporized ethylene oxide with oxygen and argon manometrically and the mixture was stored in a Pyrex flask connected t the driven section of shock tube. Reflected shock temperatures were computed from the measured incident shock speed and the other input data making the assumption that the composition of the mixture is fixed in any thermodynamic process by the initial composition to be shocked. The program, originally written by Gordon and McBride, has been modified to run on an IBM/PC. Thermodynamic properties of ethylene oxide, oxygen and argon were computed from polynomial fits to JANAF thermodynamical data.

  8. Monodisperse nonionic isoprenoid-type hexahydrofarnesyl ethylene oxide surfactants: high throughput lyotropic liquid crystalline phase determination.

    PubMed

    Fong, Celesta; Weerawardena, Asoka; Sagnella, Sharon M; Mulet, Xavier; Krodkiewska, Irena; Chong, Josephine; Drummond, Calum J

    2011-03-15

    The neat and lyotropic phase behavior of eight new ethylene oxide amphiphiles (EO = 1-8) with a hexahydrofarnesyl chain (3,7,11-trimethyldodecyl) and narrow polydispersity (>98.5% purity) is reported. Below five EO units the behavior of the neat surfactants show only a glass transition, Tg ∼ -90 °C. Above four EO units, crystallization (Tcrys) and crystal-isotropic liquid (Tm) transitions are also observed that increase with degree of ethoxylation of the surfactant headgroup. The lyotropic liquid crystalline phase behavior spans a complex spectrum of surfactant-water interfacial curvatures. Specifically, inverse phases are present below ambient temperatures for EO < 4, with HFarn(EO)2 exhibiting an inverse hexagonal (H(II)) phase stable to dilution. The phase diagram of HFarn(EO)3 displays both the gyroid (Ia3d) and double diamond (Pn3m) inverse bicontinuous cubic phases, with the latter being thermodynamically stable in excess water within the physiological regime. There is a strong preference for planar bilayer structures at intermediate headgroup ethoxylation, with the crossover to normal phases occurring at HFarn(EO)(7-8) which exhibits normal hexagonal (H(I)) and cubic (Q(I)) phases at ambient temperatures. The toxicity of colloidal dispersions of these EO amphiphiles was assayed against normal breast epithelial (HMEpiC) and breast cancer (MCF7) cell lines. The IC50 of the EO amphiphiles was similar in both cell lines with moderate toxicity ranging from ca. <5 to 140 μM in an in vitro cell viability assay. Observations are qualitatively rationalized in terms of the molecular geometry of the surfactant. The physicochemical behavior of the HFarnesyl ethylene oxide amphiphiles is compared to other ethylene oxide surfactants.

  9. 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.

  10. Chemical kinetic analysis of detonability-enhancing strategies for ethylene-oxidizer mixtures

    NASA Astrophysics Data System (ADS)

    St. George, Andrew; Driscoll, R.; Anand, V.; Gutmark, E.

    2016-11-01

    Four detailed chemical kinetic mechanisms are used in conjunction with an empirical detonation cell width model to numerically assess strategies to increase the detonation sensitivity of ethylene-oxidizer mixtures. Using this method, reasonable agreement is achieved with computed cell width and the available experimental data. Elevated initial pressures significantly reduce cell width for a wide range of equivalence ratios, yielding 80% reduction at stoichiometric conditions for a tenfold increase in pressure. Elevated initial temperatures have almost no effect on the cell width at stoichiometric conditions, but yield 80% reduction at lean conditions when the initial temperature is doubled. Reduced nitrogen dilution within the oxidizer dramatically reduces the cell width for the entire computed range of equivalence ratios. Introducing hydrogen as a fuel additive yields mild improvement to detonation sensitivity at stoichiometric conditions, but requires relatively high H2 concentrations and is ineffective when coupled with elevated initial pressures. Introduction of supplemental oxygen and increasing the initial reactant pressure appears to be the most effective approach to enhance detonability for ethylene-oxidizer mixtures.

  11. 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)

  12. 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.

  13. 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

  14. 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.

  15. Nanostructured carbon-crystalline titania composites from microphase separation of poly(ethylene oxide-b-acrylonitrile) and titania sols.

    PubMed

    Stefik, Morgan; Lee, Jinwoo; Wiesner, Ulrich

    2009-05-14

    A simple "one-pot" method utilizing a graphitic carbon source containing poly(ethylene oxide-b-acrylonitrile) diblock copolymer as a structure directing agent was used to synthesize carbon-crystalline titania composites as well as crystalline mesoporous titania materials after oxidative carbon removal.

  16. 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. © 2016 American Society of Plant Biologists. All Rights

  17. [Preparation of budesonide-poly (ethylene oxide) solid dispersions using supercritical carbon dioxide and in vitro evaluation].

    PubMed

    Liu, Hui; Pan, Wei-san; Zhou, Li-li; Zhang, Zhi-hong

    2007-02-01

    An application of supercritical fluids technology for processing of budesonide-poly (ethylene oxide) solid dispersions was presented. The correlations of the operation parameters in the preparation process were studied. Solid dispersions of budesonide in poly (ethylene oxide) were prepared using a static method for supercritical carbon dioxide and characterized by powder X-ray diffractometry, differential scanning calorimetry, intrinsic dissolution, and in vitro dissolution. It was found that the optimum condition of solid dispersions formation was as follows: temperature, 40 degrees C ; pressure, 20 MPa; the ratio of budesonide and poly (ethylene oxide) , 1: 10. Drug existed in amorphous state in hydrophilic poly (ethylene oxide) carriers and intrinsic solubility and dissolution rates were significantly enhanced. The mechanism of the enhanced dissolution may be attributed to the amorphous character of the budesonide, improvement of the wettability of the hydrophobic budesonide, together with the formation of hydrogen bond of budesonide and hydrophilic poly (ethylene oxide). The supercritical fluids process can be used as an alternative method for preparation of solid dispersions.

  18. Exposure of hematopoietic stem cells to ethylene oxide during processing represents a potential carcinogenic risk for transplant recipients.

    PubMed

    Butterworth, Byron E; Chapman, John R

    2007-12-01

    Stem cells for transplantation are obtained from bone marrow, umbilical cord blood, and peripheral blood. A rare complication of hematopoietic stem cell transplantation is donor cell-derived leukemia (DCL). The donors remain cancer free and the causes of these DCL are unknown. Stem cells must repopulate the bone marrow and then give rise to all hematopoietic cells for the rest of the transplant recipient's life. No procedure is acceptable that might introduce precancerous or cancerous mutations in cells performing such a critical function. Medical disposable sets consisting of bags, tubing sets and freezing containers are used to collect, purify and store stem cells. Sterilization of disposables with ethylene oxide is widespread, even though those sets unavoidably retain residual amounts of ethylene oxide which is a potent, direct-acting mutagen and clastogen that has been demonstrated to induce hematopoietic cancer in mice, rats and human beings. Potential exposure levels to ethylene oxide during processing under proposed US FDA guidelines for residual ethylene oxide would be biologically active and present a significant risk factor for DCL. For direct-acting mutagens, there is no recognized "no effect" dose using currently accepted cancer risk assessment models. The safety concerns with ethylene oxide can be eliminated by the use of alternative technologies including electron beam, gamma irradiation, or steam for the sterilization of all products used for stem cell processing and storage.

  19. Working conditions and health effects of ethylene oxide exposure at hospital sterilization sites.

    PubMed

    Sobaszek, A; Hache, J C; Frimat, P; Akakpo, V; Victoire, G; Furon, D

    1999-06-01

    Ethylene oxide (EtO) is a powerful disinfectant and sterilant for heat-sensitive surgical items and instruments. Its use in hospitals constitutes an important source of occupational exposure that is sometimes underestimated, such as in cases of EtO device malfunction when the safety rules of procedure are not strictly followed or when individual or collective protective equipment is lacking. We carried out a descriptive study of the health care workers who were assigned to EtO sterilization units of the Lille University Hospital Centre in Lille, France (n = 16). Before the modification of the sterilization units in the development of a single, central sterilization site, we studied the workplaces, occupational conditions, and work procedures of the health care workers exposed to EtO. The aim was to assess the risk of EtO overexposure of the workers in order to improve workers' health and security in the future sterilization center. The study was based on a physical examination, a questionnaire covering each subject's personal and occupational history, and a complete ocular examination. For occupational conditions, the studies of each workplace were also performed by the occupational physician. Area and personal breathing air samplings were performed at each exposure site. Fourteen of the 16 operators had posterior and anterior subcapsular lens opacities, three of which seemed to be directly and primarily related to occupational exposure; the other ten seemed to be rather common and compatible with age. High levels of EtO exposure were reported in the oldest site (90 parts per million [ppm] during the changing of the gas bottle), where exposure often exceeded French threshold limits (permissible exposure limit: 1 ppm 8-hour time-weighted average (TWA) in air; short-term excursion limit: 5 ppm 15-minute TWA in air), or the current US recommended and legal exposure limits for EtO advocated by the Occupational Safety and Health Administration and the American

  20. Sterilization of medical devices by ethylene oxide, determination of the dissipation of residues, and use of Green Fluorescent Protein as an indicator of process control.

    PubMed

    Dias, Fábio N; Ishii, Marina; Nogaroto, Sergio L; Piccini, Bruno; Penna, Thereza C V

    2009-11-01

    Ethylene oxide (EO) is used to sterilize Oxygenator and Tubing applied to heart surgery. Residual levels of EO and its derivatives, ethylene chlorohydrin (ECH) and ethylene glycol (EG), may be hazardous to the patients. Therefore, it must be removed by the aeration process. This study aimed to estimate the minimum aeration time for these devices to attain safe limits for use (avoiding excessive aeration time) and to evaluate the Green Fluorescent Protein (GFP) as a biosensor capable of best indicating the distribution and penetration of EO gas throughout the sterilization chamber. Sterilization cycles of 2, 4, and 8 h were monitored by Bacillus atrophaeus ATCC 9372 as a biological indicator (BI) and by the GFP. Residual levels of EO, ECH, and EG were determined by gas chromatography (GC), and the residual dissipation was studied. Safe limits were reached right after the sterilization process for Oxygenator and after 204 h of aeration for Tubing. In the 2 h cycle, the GFP concentration decreased from 4.8 (+/-3.2)% to 7.5 (+/-2.5)%. For the 4 h cycle, the GFP concentration decreased from 17.4 (+/-3.0)% to 21.5 (+/-6.8)%, and in the 8 h cycle, it decreased from 22.5 (+/-3.2)% to 23.9 (+/-3.9)%. This finding showed the potentiality for GFP applications as an EO biosensor.

  1. Ripening, storage temperature, ethylene action, and oxidative stress alter apple peel phytosterol metabolism.

    PubMed

    Rudell, David R; Buchanan, David A; Leisso, Rachel S; Whitaker, Bruce D; Mattheis, James P; Zhu, Yanmin; Varanasi, Vijay

    2011-08-01

    The chilling conditions of apple cold storage can provoke an economically significant necrotic peel disorder called superficial scald (scald) in susceptible cultivars. Disorder development can be reduced by inhibiting ethylene action or oxidative stress as well as intermittent warming. It was previously demonstrated that scald is preceded by a metabolomic shift that results in altered levels of various classes of triterpenoids, including metabolites with mass spectral features similar to β-sitosterol. In this study, a key class of phytosterol metabolites was identified. Changes in peel tissue levels of conjugates of β-sitosterol and campesterol, including acylated steryl glycosides (ASG), steryl glycosides (SG) and steryl esters (SE), as well as free sterols (FS), were determined during the period of scald development. Responses to pre-storage treatment with the ethylene action inhibitor, 1-methylcyclopropene, or an antioxidant (diphenylamine), rapid temperature elevation, and cold acclimation using intermittent warming treatments were evaluated. Diphenylamine, 1-MCP, and intermittent warming all reduced or prevented scald development. ASG levels increased and SE levels decreased in untreated control fruit during storage. Removing fruit from cold storage to ambient temperature induced rapid shifts in ASG and SE fatty acyl moieties from unsaturated to saturated. FS and SG levels remained relatively stable during storage but SG levels increased following a temperature increase after storage. ASG, SE, and SG levels did not increase during 6 months cold storage in fruit subjected to intermittent warming treatment. Overall, the results show that apple peel phytosteryl conjugate metabolism is influenced by storage duration, oxidative stress, ethylene action/ripening, and storage temperature.

  2. Cadmium toxicity in cultured tomato cells--role of ethylene, proteases and oxidative stress in cell death signaling.

    PubMed

    Iakimova, Elena T; Woltering, Ernst J; Kapchina-Toteva, Veneta M; Harren, Frans J M; Cristescu, Simona M

    2008-12-01

    Our aim was to investigate the ability of cadmium to induce programmed cell death in tomato suspension cells and to determine the involvement of proteolysis, oxidative stress and ethylene. Tomato suspension cells were exposed to treatments with CdSO(4) and cell death was calculated after fluorescein diacetate staining of the living cells. Ethylene was measured in a flow-through system using a laser-driven photo acoustic detector; hydrogen peroxide was determined by chemiluminescence in a ferricyanide-catalysed oxidation of luminol. We have demonstrated that cadmium induces cell death in tomato suspension cells involving caspase-like proteases, indicating that programmed cell death took place. Using range of inhibitors, we found that cysteine and serine peptidases, oxidative stress, calcium and ethylene are players in the cadmium-induced cell death signaling. Cadmium-induced cell death in tomato suspension cells exhibits morphological and biochemical similarities to plant hypersensitive response and to cadmium effects in animal systems.

  3. 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.

  4. A study on optical absorption and constants of doped poly(ethylene oxide)

    NASA Astrophysics Data System (ADS)

    Al-Faleh, R. S.; Zihlif, A. M.

    2011-05-01

    Thin films of polymer electrolyte based on poly(ethylene oxide) doped with sodium iodide (NaI) were prepared using the solution cast method. The films obtained have average thickness of 70 μm and different NaI concentrations. Absorption and reflectance spectra of UV-radiation were studied in the wavelength range 300-800 nm. The optical results were analyzed in terms of absorption formula for non-crystalline materials. The optical energy gap and the basic optical constants, refractive index, and dielectric constants of the prepared films have been investigated and showed a clear dependence on the NaI concentration. The interpreted absorption mechanism is a direct electron transition. The observed optical energy gap for neat poly(ethylene oxide) is about 2.6 eV, and decreases to a value 2.36 eV for the film of 15 wt% NaI content. It was found that the calculated refractive index and the dielectric constants of the polymer electrolyte thin films increase with NaI content. Models were used to describe the dependences of the dielectric constant on the NaI concentration, and the refractive index on the incident photon energy.

  5. Local Structure and Ion Transport in Glassy Poly(ethylene oxide styrene) Copolymers

    NASA Astrophysics Data System (ADS)

    Yang, Han-Chang; Mays, Jimmy; Sokolov, Alexei P.; Winey, Karen I.

    2014-03-01

    Polymer electrolytes have attracted attention for a wide variety of applications in energy production such as lithium-ion batteries and fuel cells. The concept of free volume provides important information about ion mobility and chain dynamics in the polymer matrix. Researchers have recently demonstrated that ion transport in glassy polymer can be improved by designing a system with high free volume. We have studied the effect of temperature and humidity on the intermolecular correlations of poly(ethylene oxide styrene-block-styrene) (PEOSt- b-St) block copolymer and poly(ethylene oxide styrene) (PEOSt) homopolymer using in situ multi-angle x-ray scattering across a wide range of scattering angles (q = 0.007-1.5 Å-1) . An increase in backbone-to-backbone distance is observed, indicating an increase in free volume between different polymer main chains. Structural characterization of the polymer segments will be discussed together with conductivity and dielectric results to better understand the ion transport mechanism in the local environment of the polymer system. Department of Chemistry, University of Tennessee.

  6. 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.

  7. 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.

  8. Effects of ethylene oxide sterilization on 82: 18 PLLA/PGA copolymer craniofacial fixation plates.

    PubMed

    Pietrzak, William S

    2010-01-01

    Bioabsorbable devices are generally susceptible to some form of degradation or alteration of material properties in response to exposure to the terminal sterilization cycle. In addition to affecting the material strength, sterilization can also increase the rate of hydrolysis, both of which can impact clinical performance. The impact of sterilization on the material/device is unpredictable and must be empirically determined. This study examined the effects of ethylene oxide treatment on the material properties of LactoSorb 82:18 poly(L-lactic acid)-poly(glycolic acid) craniofacial plates. Compared with untreated control plates, there was no effect on the initial inherent viscosity (1.3 dL/g), the glass transition temperature (58 degrees C), or on the flexural mechanical properties. Furthermore, there was no effect on the in vitro rate of hydrolysis and mechanical strength loss profile. This provides evidence that the ethylene oxide sterilization cycle is compatible with these copolymer plates and that such treatment should not affect the clinical performance.

  9. Nanopowder Metal Oxide for Photoluminescent Gas Sensing

    NASA Astrophysics Data System (ADS)

    Zhyrovetsky, V. M.; Popovych, D. I.; Savka, S. S.; Serednytski, A. S.

    2017-02-01

    Gas sensing properties of metal oxide nanopowders (ZnO, TiO2, WO3, SnO2) with average diameters of 40-60 nm were analyzed by room-temperature photoluminescence spectroscopy. The influence of gas environment (O2, N2, H2, CO, CO2) on the emission intensity was investigated for metal oxide nanopowders with surface doped by impurities (Pt, Ag, Au, Sn, Ni or Cu). Established physicochemical regularities of modification of surface electronic states of initial and doped nanopowders during gas adsorption. The nature of metal oxide nanopowder gas-sensing properties (adsorption capacity, sensitivity, selectivity) has been established and the design and optimal materials for the construction of the multi-component sensing matrix have been selected.

  10. Laboratory Studies on the Formation of Three C2H4O Isomers-Acetaldehyde (CH3CHO), Ethylene Oxide (c-C2H4O), and Vinyl Alcohol (CH2CHOH)-in Interstellar and Cometary Ices

    NASA Astrophysics Data System (ADS)

    Bennett, Chris J.; Osamura, Yoshihiro; Lebar, Matt D.; Kaiser, Ralf I.

    2005-11-01

    Laboratory experiments were conducted to unravel synthetic routes to form three C2H4O isomers-acetaldehyde (CH3CHO), ethylene oxide (c-C2H4O), and vinyl alcohol (CH2CHOH)-in extraterrestrial ices via electronic energy transfer processes initiated by electrons in the track of MeV ion trajectories. Here we present the results of electron irradiation on a 2:1 mixture of carbon dioxide (CO2) and ethylene (C2H4). Our studies suggest that suprathermal oxygen atoms can add to the carbon-carbon π bond of an ethylene molecule to form initially an oxirene diradical (addition to one carbon atom) and the cyclic ethylene oxide molecule (addition to two carbon atoms) at 10 K. The oxirene diradical can undergo a [1, 2]-H shift to the acetaldehyde molecule. Both the ethylene oxide and the acetaldehyde isomers can be stabilized in the surrounding ice matrix. To a minor amount, suprathermal oxygen atoms can insert into a carbon-hydrogen bond of the ethylene molecule, forming vinyl alcohol. Once these isomers have been synthesized inside the ice layers of the coated grains in cold molecular clouds, the newly formed molecules can sublime as the cloud reaches the hot molecular core stage. These laboratory investigations help to explain astronomical observations by Nummelin et al. and Ikeda et al. toward massive star-forming regions and hot cores, where observed fractional abundances of these isomers are higher than can be accounted for by gas-phase reactions alone. Similar synthetic routes could help explain the formation of acetaldehyde and ethylene oxide in comet C/1995 O1 (Hale-Bopp) and also suggest a presence of both isomers in Titan's atmosphere.

  11. Bovine bone screws: metrology and effects of chemical processing and ethylene oxide sterilization on bone surface and mechanical properties.

    PubMed

    Haje, D P; Volpon, J B; Moro, C A

    2009-03-01

    We assess the effects of chemical processing, ethylene oxide sterilization, and threading on bone surface and mechanical properties of bovine undecalcified bone screws. In addition, we evaluate the possibility of manufacturing bone screws with predefined dimensions. Scanning electronic microscopic images show that chemical processing and ethylene oxide treatment causes collagen fiber amalgamation on the bone surface. Processed screws hold higher ultimate loads under bending and torsion than the in natura bone group, with no change in pull-out strength between groups. Threading significantly reduces deformation and bone strength under torsion. Metrological data demonstrate the possibility of manufacturing bone screws with standardized dimensions.

  12. Development of an Optical Gas Leak Sensor for Detecting Ethylene, Dimethyl Ether and Methane

    PubMed Central

    Tan, Qiulin; Pei, Xiangdong; Zhu, Simin; Sun, Dong; Liu, Jun; Xue, Chenyang; Liang, Ting; Zhang, Wendong; Xiong, Jijun

    2013-01-01

    In this paper, we present an approach to develop an optical gas leak sensor that can be used to measure ethylene, dimethyl ether, and methane. The sensor is designed based on the principles of IR absorption spectrum detection, and comprises two crossed elliptical surfaces with a folded reflection-type optical path. We first analyze the optical path and the use of this structure to design a miniature gas sensor. The proposed sensor includes two detectors (one to acquire the reference signal and the other for the response signal), the light source, and the filter, all of which are integrated in a miniature gold-plated chamber. We also designed a signal detection device to extract the sensor signal and a microprocessor to calculate and control the entire process. The produced sensor prototype had an accuracy of ±0.05%. Experiments which simulate the transportation of hazardous chemicals demonstrated that the developed sensor exhibited a good dynamic response and adequately met technical requirements. PMID:23539025

  13. Process for selected gas oxide removal by radiofrequency catalysts

    DOEpatents

    Cha, Chang Y.

    1993-01-01

    This process to remove gas oxides from flue gas utilizes adsorption on a char bed subsequently followed by radiofrequency catalysis enhancing such removal through selected reactions. Common gas oxides include SO.sub.2 and NO.sub.x.

  14. 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.

  15. Ethylene reduces plant gas exchange and growth of lettuce grown from seed to harvest under hypobaric and ambient total pressure.

    PubMed

    He, Chuanjiu; Davies, Fred T

    2012-03-01

    Naturally occurring high levels of ethylene can be a problem in spaceflight and controlled environment agriculture (CEA) leading to sterility and irregular plant growth. There are engineering and safety advantages of growing plants under hypobaria (low pressure) for space habitation. The goals of this research were to successfully grow lettuce (Lactuca sativa cv. Buttercrunch) in a long-term study from seed to harvest under hypobaric conditions, and to investigate how endogenously produced ethylene affects gas exchange and plant growth from seed germination to harvest under hypobaric and ambient total pressure conditions. Lettuce was grown under two levels of total gas pressure [hypobaric or ambient (25 or 101 kPa)] in a long-term, 32-day study. Significant levels of endogenous ethylene occurred by day-15 causing reductions in photosynthesis, dark-period respiration, and a subsequent decrease in plant growth. Hypobaria did not mitigate the adverse ethylene effects on plant growth. Seed germination was not adversely affected by hypobaria, but was reduced by hypoxia (6 kPa pO(2)). Under hypoxia, seed germination was higher under hypobaria than ambient total pressure. This research shows that lettuce can be grown from seed to harvest under hypobaria (≅25% of normal earth ambient total pressure). Copyright © 2011 Elsevier GmbH. All rights reserved.

  16. 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

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

    PubMed

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

    2009-01-01

    To evaluate, under microscopic examination, the structural changes displayed by the trabecular and cortical bones after being processed chemically and sterilized by ethylene oxide. 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. 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. 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.

  18. Monitoring occupational exposure to ethylene oxide by the determination of hemoglobin adducts.

    PubMed

    van Sittert, N J; Beulink, G D; van Vliet, E W; van der Waal, H

    1993-03-01

    In a study on workers in a chemical plant where ethylene oxide (EtO) is manufactured and partly used for ethylene glycol production, exposure to EtO was monitored during annual periodic health assessments in January 1988, December 1988, and March 1990 by the determination of the level of 2-hydroxyethylvaline (HOEtVal) in hemoglobin. The HOEtVal levels in workers corresponded with the potential EtO exposures. The highest level was found in December 1988, in blood samples collected 1-2 months after a shut-down, maintenance, and start-up program. The range of adduct levels found in the three examinations indicated that average EtO exposures during the 4 months preceding blood sampling were below 0.5 ppm. It was demonstrated that the method allows for the accurate monitoring of low levels of EtO exposure and provides personalized time-integrated exposure data with great discriminative power. In addition, the method may serve to identify unexpected personal exposures, which may lead to targeted exposure control measures.

  19. Biomaterial based sulphur di oxide gas sensor

    NASA Astrophysics Data System (ADS)

    Ghosh, P. K.; Sarkar, A.

    2013-06-01

    Biomaterials are getting importance in the present research field of sensors. In this present paper performance of biomaterial based gas sensor made of gum Arabica and garlic extract had been studied. Extract of garlic clove with multiple medicinal and chemical utility can be proved to be useful in sensing Sulphur di Oxide gas. On exposure to Sulphur di Oxide gas the material under observation suffers some temporary structural change, which can be observed in form of amplified potentiometric change through simple electronic circuitry. Exploiting this very property a potentiometric gas sensor of faster response and recovery time can be designed. In this work sensing property of the said material has been studied through DC conductance, FTIR spectrum etc.

  20. Evaluation of the matrix effect on gas chromatography--mass spectrometry with carrier gas containing ethylene glycol as an analyte protectant.

    PubMed

    Fujiyoshi, Tomoharu; Ikami, Takahito; Sato, Takashi; Kikukawa, Koji; Kobayashi, Masato; Ito, Hiroshi; Yamamoto, Atsushi

    2016-02-19

    The consequences of matrix effects in GC are a major issue of concern in pesticide residue analysis. The aim of this study was to evaluate the applicability of an analyte protectant generator in pesticide residue analysis using a GC-MS system. The technique is based on continuous introduction of ethylene glycol into the carrier gas. Ethylene glycol as an analyte protectant effectively compensated the matrix effects in agricultural product extracts. All peak intensities were increased by this technique without affecting the GC-MS performance. Calibration curves for ethylene glycol in the GC-MS system with various degrees of pollution were compared and similar response enhancements were observed. This result suggests a convenient multi-residue GC-MS method using an analyte protectant generator instead of the conventional compensation method for matrix-induced response enhancement adding the mixture of analyte protectants into both neat and sample solutions. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Participation of hot electrons in oxygen adsorption and ethylene oxidation on metals

    SciTech Connect

    Maganyuk, A.P.; Starkovskii, N.I.; Yurchuk, S.Y.

    1995-04-01

    This paper reports the results obtained in the course of generating hot electrons by a device that is easier to fabricate and has more stability to chemically active compounds that a metal-insulator-metal systems: a Shottky-barrier diode having planar contact between a metal and a donor-doped semiconductor. In order to elucidate the potential effect of the promotion of chemical transformation by hot electrons, two specimens of different barrier heights were used: one a silicon-gold contact, the second a gallium arsenide film coated with layers of silver and a InNi alloy (3% Ni). These contacts were used to measure the current-voltage curve, the peak intensities curves which were proportional to the quantities of oxygen, water and carbon dioxide employed, and the peak intensities proportional to the formation rates of ethylene oxidation products.

  2. 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.

  3. In situ preparation of poly(ethylene oxide)-SiO 2 composite polymer electrolytes

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Lee, J. Y.; Hong, L.

    Amorphous poly(ethylene oxide) (PEO)-SiO 2 composites are prepared by in situ reactions that involve the simultaneous formation of the polymer network and inorganic nanoparticles. The polymer matrix is formed by ultraviolet irradiation of a PEO macromer, and silica is produced in situ by the sol-gel method. The PEO-SiO 2 composite mixed with LiBF 4 is used as a lithium-ion conducting solid electrolyte and electrochemical transport properties such as ionic conductivity and Li + transference number are measured. A significant increase in the Li + transference number, up to 0.56, is found together with a slight decrease in the ionic conductivity. The results are interpreted in terms of interactions between the surface OH groups of the inorganic particles, the cations, the anions, and the ether oxygen atoms on the PEO backbone.

  4. Microscopic muon dynamics in the polymer electrolyte poly(ethylene oxide)

    NASA Astrophysics Data System (ADS)

    McKenzie, Iain; Cottrell, Stephen P.

    2017-07-01

    The microscopic dynamics of protons (H+) in poly(ethylene oxide) (PEO) have been investigated through a study of implanted positive muons (Mu+), which can be considered a light proton analog. The exponential decay of the muon spin polarization in zero magnetic field indicated that Mu+ hopping is in the fast fluctuation limit between 140 and 310 K and the relaxation rate was found to be sensitive to the glass transition. Mu+ dynamics in PEO was monitored via the relaxation of the muon spin polarization in a transverse field of 10 mT. Activated hopping of Mu+ was observed above the glass transition temperature with an activation barrier of 122 ±1 meV. The temperature dependence of the diamagnetic muon polarization in PEO can be explained by diffusion of radiolytic electrons.

  5. Electrospinning chitosan/poly(ethylene oxide) solutions with essential oils: Correlating solution rheology to nanofiber formation.

    PubMed

    Rieger, Katrina A; Birch, Nathan P; Schiffman, Jessica D

    2016-03-30

    Electrospinning hydrophilic nanofiber mats that deliver hydrophobic agents would enable the development of new therapeutic wound dressings. However, the correlation between precursor solution properties and nanofiber morphology for polymer solutions electrospun with or without hydrophobic oils has not yet been demonstrated. Here, cinnamaldehyde (CIN) and hydrocinnamic alcohol (H-CIN) were electrospun in chitosan (CS)/poly(ethylene oxide) (PEO) nanofiber mats as a function of CS molecular weight and degree of acetylation (DA). Viscosity stress sweeps determined how the oils affected solution viscosity and chain entanglement (Ce) concentration. Experimentally, the maximum polymer:oil mass ratio electrospun was 1:3 and 1:6 for CS/PEO:CIN and:H-CIN, respectively; a higher chitosan DA increased the incorporation of H-CIN only. The correlations determined for electrospinning plant-derived oils could potentially be applied to other hydrophobic molecules, thus broadening the delivery of therapeutics from electrospun nanofiber mats.

  6. Gelation, swelling and water vapor permeability behavior of radiation synthesized poly(ethylene oxide) hydrogels

    NASA Astrophysics Data System (ADS)

    Savaş, Hülya; Güven, Olgun

    2002-04-01

    In this study, gamma ray induced gelation of aqueous solutions of poly(ethylene oxide), (PEO) with 73.300 Da average molecular weight has been studied. Percent of conversion of polymer into gel as well as swelling behavior were investigated gravimetrically. The effect of the dose rate on these properties was studied. Within the dose rate range studied, it is observed that low dose rate irradiation favors chain scission and although the dominant effect is still crosslinking, %gelation at a given dose decreases. Water vapor permeability (Wvp) of PEO hydrogels has been studied with regard to crosslink density changes and temperature. The water vapor permeability of hydrogels obtained at high dose rate was found to be lower than those obtained at low dose rate which was related to higher crosslink density achieved under higher dose rate irradiations.

  7. 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.

  8. Variables affecting simulated use determination of residual ethylene oxide in medical devices.

    PubMed

    Centola, D T; Ayoub, K I; Lao, N T; Lu, H T; Page, B F

    2001-01-01

    In autumn 1993, AAMI/ST/WG 63, Sterilization Residuals Working Group undertook the task of studying factors involved in determining the amount of residual ethylene oxide in medical devices after sterilization and developing a protocol for controlling the relevant variables. The protocol was evaluated by conducting a round robin study consisting of 8 participating laboratories from around the country. Results of this round robin study demonstrated the range over which results may vary despite controls placed on the time and temperature at which determinations were conducted. The data from the study suggest that small, random variations in technique during short sample extraction times can lead to variability in the results. Variables such as initial water temperature, oven temperature, weighing of sample, and length of extraction should be carefully controlled. Inherent variations in the material composition of similar devices are possible contributing factors. The efforts of this working group and the subsequent evaluation and discussion of its findings are presented.

  9. Interpreting and understanding microbial data in validation of ethylene oxide sterilization processes.

    PubMed

    Mosley, Gregg A; Houghtling, Clark C

    2005-01-01

    Ethylene oxide (EtO) sterilization validation programs are based on historical data, industry experience, and theoretical knowledge. When designing a specific program, the knowledge and experience of the individuals responsible often determines how accurately these data, experiences, and theories are applied. The assumptions and premises that form the foundation for the validation program are critical to the ultimate safety ofproducts distributed to the marketplace. Demonstrating appropriate microbial lethality is the ultimate purpose of sterilization validation. When using EtO processes, this is usually dependent on the proper use of biological indicators (Bls) in conjunction with the specific product, load, and cycle to be validated. The authors discuss the use of Bls, determination of microbial lethality, process controls, and variables related to these subjects in order to assist validation teams in designing successful validation programs, and/or problem solving when unexpected results are obtained.

  10. Polyelectrolyte-like behaviour of poly(ethylene-oxide) solutions with added monovalent salt

    NASA Astrophysics Data System (ADS)

    Lal, Jyotsana; Hakem, Ilhem-Faiza

    2004-03-01

    Solvent effects on the conformation of poly(ethylene-oxide) (PEO) and complexation of PEO by monovalent cations, have been examined by using small-angle neutron scattering. In methanol and acetonitrile, a big change in interchain interaction, osmotic compressibility and local chain conformation have been observed upon addition of small amounts of potassium iodide. The amplitude of the total intensity decreases significantly and a peak at a certain value of the wavevector q* appears as signature of a polyelectrolyte-like behaviour. With further addition of salt, the ionic strength of the solution increases and potassium binding becomes less favorable: the binding constant decreases with the ionic strength and PEO behaves as a neutral polymer with excluded volume. No association between PEO and potassium iodide was observed in aqueous solutions. Reference: I.F. Hakem and J. Lal. Europhysics letters, 64 (2), 204, 2003

  11. Ethylene Oxide: Acute Four-Hour and One-Hour Inhalation Toxicity Testing in Rats

    PubMed Central

    Snellings, William M.; Nachreiner, Donald J.; Pottenger, Lynn H.

    2011-01-01

    Ethylene oxide was tested on groups of rats for either 4-hour or 1-hour inhalation exposure, followed by 14 days of observation. Groups of five Sprague-Dawley rats/sex were exposed, and clinical signs and mortality were recorded. Clinical signs noted included irregular breathing, absence of certain reflexes, and tremors. Rats that died had moderate to severe pulmonary congestion. The calculated LC50 values, reported as ppm by volume (with 95% confidence limits), were as follows. 4-hour LC50 values were 1972 (1887 to 2061) ppm for males; 1537 (1391 to 1698) ppm for females; 1741 (1655 to 1831) ppm for the combined sexes. The 1-hour LC50 values were 5748 (5276 to 6262) ppm for males; 4439 (4034 to 4884) ppm for females; 5029 (4634 to 5459) ppm for the combined sexes. PMID:21785591

  12. Industrial-hygiene characterization of ethylene oxide exposures of hospital and nursing-home workers

    SciTech Connect

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

    1986-12-01

    Industrial-hygiene surveys were conducted at 12 hospitals and one nursing home to determine possible employee exposure to ethylene oxide (EtO). Different types of exposure situations existed at each of the facilities as a result of various engineering controls, administrative controls and work practices. Sampling indicated that the time-weighted averages (TWAs) of exposure over periods of 36 to 724 minutes ranged from below the limit of detection to 6.7 parts per million (ppm). Personal short-term exposure levels covering 2 to 30 minutes ranged from less than the limit of detection to 103.2ppm. Factors found to be responsible for these higher-than-permissible levels of EtO exposure included improper installation or lack of engineering controls (such as improper placement of the sterilizing operations), unbalanced ventilation systems, and lack of administrative controls resulting in inappropriate work practices.

  13. Collective motion in Poly(ethylene oxide)/poly(methylmethacrylate) blends

    SciTech Connect

    Farago, Bela; Chen Chunxia; Maranas, Janna K.; Kamath, Sudesh; Colby, Ralph H.; Pasquale, Anthony J.; Long, Timothy E.

    2005-09-01

    We present neutron spin echo and structural measurements on a perdeutereted miscible polymer blend: poly(ethylene oxide)[PEO]/poly(methyl methacrylate)[PMMA], characterized by a large difference in component glass transition temperatures and minimal interactions. The measurements cover the q range 0.35 to 1.66 A{sup -1} and the temperature range T{sub g}-75 to T{sub g}+89 K, where T{sub g} is the blend glass transition. The spectra, obtained directly in the time domain, are very broad with stretching parameters {beta}{approx}0.30. The relaxation times vary considerably over the spatial range considered however at none of the q values do we see two distinct relaxation times. At small spatial scales relaxations are still detectable at temperatures far below T{sub g}. The temperature dependence of these relaxation times strongly resembles the {beta}-relaxation process observed in pure PMMA.

  14. Metal oxide membranes for gas separation

    DOEpatents

    Anderson, Marc A.; Webster, Elizabeth T.; Xu, Qunyin

    1994-01-01

    A method for permformation of a microporous ceramic membrane onto a porous support includes placing a colloidal suspension of metal oxide particles on one side of the porous support and exposing the other side of the porous support to a drying stream of gas or a reactive gas stream so that the particles are deposited on the drying side of the support as a gel. The gel so deposited can be sintered to form a supported ceramic membrane having mean pore sizes less than 30 Angstroms and useful for ultrafiltration, reverse osmosis, or gas separation.

  15. Metal oxide membranes for gas separation

    DOEpatents

    Anderson, M.A.; Webster, E.T.; Xu, Q.

    1994-08-30

    A method for formation of a microporous ceramic membrane onto a porous support includes placing a colloidal suspension of metal oxide particles on one side of the porous support and exposing the other side of the porous support to a drying stream of gas or a reactive gas stream so that the particles are deposited on the drying side of the support as a gel. The gel so deposited can be sintered to form a supported ceramic membrane having mean pore sizes less than 30 Angstroms and useful for ultrafiltration, reverse osmosis, or gas separation. 4 figs.

  16. 21 CFR 868.1700 - Nitrous oxide gas analyzer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nitrous oxide gas analyzer. 868.1700 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1700 Nitrous oxide gas analyzer. (a) Identification. A nitrous oxide gas analyzer is a device intended to measure the concentration of nitrous oxide...

  17. 21 CFR 868.1700 - Nitrous oxide gas analyzer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nitrous oxide gas analyzer. 868.1700 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1700 Nitrous oxide gas analyzer. (a) Identification. A nitrous oxide gas analyzer is a device intended to measure the concentration of nitrous oxide...

  18. Detection of ethylene gas in exhaled breath of people living in landfill using CO{sub 2} laser photoacoustic spectroscopy with multicomponent analysis

    SciTech Connect

    Oktafiani, Fitri Stiyabudi, Rizky; Amin, Mochamad Nurul; Mitrayana

    2016-06-17

    The photoacoustic spectrometer (PAS) had been built and the performance had been determined. The research was based on the conversion of the absorbed middle infra red (IR) radiation by gas confined in a closed PAS cell into standing acoustic wave, which could be detected by a suitable electroacoustic transducer such as a microphone. The lowest detection limit for this setup was (57,1 ± 0,3) ppb and quality factor was (14,5 ± 0,6) for ethylene gas in 10P14 CO{sub 2} laser line. Then, this PAS was used to measure of ethylene gas concentration in breath sample of people living in near the Piyungan Bantul Yogyakarta landfill. The result from multicomponent analysis showed that PAS enable to measure the lowest concentration of volatile organic compound (VOC), such as ethylene, which occured on ambien air in Piyungan landfill. Variaty of distance area applied in this research. In the range of ±0,5 km from landfill, we obtained the concentration of ethylene gas concentration for human breath was (1,520 ± 0,002) ppm, while in the range of ±45 km, the ethylene gas concentration for human breath was (0,424 ± 0,002) ppm. Ethylene gas concentrations in exhaled gas decreased along with increasing distance variation of the landfill.

  19. 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.

  20. Sterilization and strength of 70/30 polylactide cages: e-beam versus ethylene oxide.

    PubMed

    Smit, Theo H; Thomas, Kevin A; Hoogendoorn, Roel J W; Strijkers, Gustav J; Helder, Marco N; Wuisman, Paul I J M

    2007-04-01

    In vitro and in vivo studies on the degradation of 70/30 poly(L,DL-lactide) (PLDLLA) cages. To evaluate the effect of e-beam and ethylene oxide sterilization on degradation and strength. e-beam-sterilized PLDLLA cages were shown to maintain mechanical strength for at least 6 months during degradation studies in vitro. Yet failure of the cages was observed after only 3 months in vivo. We hypothesized that degradation characteristics and mechanical strength could be improved by sterilizing the cages through ethylene oxide (EtO) instead of e-beam. PLDLLA cages were sterilized either by e-beam or EtO, and degraded in phosphate-buffered saline. Each month, cages were compressed until failure. Inherent viscosity was determined as a measure of degradation. For the in vivo evaluation, e-beam- or EtO-sterilized cages were implanted at L3-L4 in a standardized goat model. After 3 or 6 months, retrieved segments were scanned by high-resolution magnetic resonance imaging. Also, inherent viscosity of the polymer was measured. e-beam sterilization strongly decreased inherent viscosity of PLDLLA compared with EtO sterilization, but initial strength was only affected marginally. After 6 months, the strength of the e-beam-sterilized cages dropped, while that of EtO-sterilized cages was maintained. Degradation in vivo was slightly faster than in vitro. In both groups, however, mechanical failure occurred at 3 months after implantation. Inherent viscosity decreases with degradation time, but strength only decreases when inherent viscosity is below a certain threshold. Above this threshold, mechanical strength is a property of the polymer and independent of inherent viscosity. e-beam sterilization strongly decreases inherent viscosity and thus advances mechanical degradation. EtO sterilization delays degradation but does not increase initial strength. Early failure of PLDLLA cages in the goat model thus is unrelated to sterilization method and requires further study.

  1. Poly(ethylene oxide) star polymer adsorption at the silica/aqueous interface and displacement by linear poly(ethylene oxide).

    PubMed

    Saigal, Trishna; Riley, John K; Golas, Patricia Lynn; Bodvik, Rasmus; Claesson, Per M; Matyjaszewski, Krzysztof; Tilton, Robert D

    2013-03-26

    Multiarm star copolymers with approximately 460 poly(ethylene oxide) (PEO) arms that have a degree of polymerization N = 45 were synthesized via atom transfer radical polymerization (ATRP) of PEO-methacrylate macromonomers in the presence of divinyl benzene cross-linkers. These are an example of molecular or nanoparticulate brushes that are of interest as steric stabilizers or boundary lubrication agents when adsorbed from solution to a solid/aqueous interface. We use ellipsometry to measure adsorption isotherms at the silica/aqueous interface for PEO star polymers and linear PEO chains having molecular weights comparable either to the star polymer or to the individual arms. The compactness of the PEO star polymers (molecular weight 1.2 × 10(6)) yields a saturation surface excess concentration that is approximately 3.5 times greater than that of the high molecular weight (1 × 10(6)) linear PEO. Adsorption of low molecular weight (6000) linear PEO was below the detection limit. Competitive adsorption experiments were conducted with ellipsometry, complemented by independent quartz crystal microbalance with dissipation (QCM-D) measurements. Linear PEO (high molecular weight) displaced preadsorbed PEO star polymers over the course of approximately 1.5 h, to form a mixed adsorbed layer having not only a significantly lower overall polymer surface excess concentration, but also a significantly greater amount of hydrodynamically entrapped water. Challenging a preadsorbed linear PEO (high molecular weight) layer with PEO star polymers produced no measurable change in the overall polymer surface excess concentration, but changes in the QCM-D energy dissipation and resonance frequency suggested that the introduction of PEO star polymers caused a slight swelling of the layer with a correspondingly small increase in entrapped water content.

  2. Exploring biochemical pathways for mono-ethylene glycol (MEG) synthesis from synthesis gas.

    PubMed

    Islam, M Ahsanul; Hadadi, Noushin; Ataman, Meric; Hatzimanikatis, Vassily; Stephanopoulos, Gregory

    2017-05-01

    Mono-ethylene glycol (MEG) is an important petrochemical with widespread use in numerous consumer products. The current industrial MEG-production process relies on non-renewable fossil fuel-based feedstocks, such as petroleum, natural gas, and naphtha; hence, it is useful to explore alternative routes of MEG-synthesis from gases as they might provide a greener and more sustainable alternative to the current production methods. Technologies of synthetic biology and metabolic engineering of microorganisms can be deployed for the expression of new biochemical pathways for MEG-synthesis from gases, provided that such promising alternative routes are first identified. We used the BNICE.ch algorithm to develop novel and previously unknown biological pathways to MEG from synthesis gas by leveraging the Wood-Ljungdahl pathway of carbon fixation of acetogenic bacteria. We developed a set of useful pathway pruning and analysis criteria to systematically assess thousands of pathways generated by BNICE.ch. Published genome-scale models of Moorella thermoacetica and Clostridium ljungdahlii were used to perform the pathway yield calculations and in-depth analyses of seven (7) newly developed biological MEG-producing pathways from gases, including CO2, CO, and H2. These analyses helped identify not only better candidate pathways, but also superior chassis organisms that can be used for metabolic engineering of the candidate pathways. The pathway generation, pruning, and detailed analysis procedures described in this study can also be used to develop biochemical pathways for other commodity chemicals from gaseous substrates. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  3. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. 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.

  5. Electrochemical Characterization of poly (styrene-b-ethylene oxide)/LiTFSI Lamellar Diblock Copolymer Electrolyte System

    NASA Astrophysics Data System (ADS)

    Balsara, Nitash; Panday, Ashoutosh; Mullin, Scott; Wanakule, Nisita

    2009-03-01

    We present the electrochemical characterization studies of symmetric poly (styrene-b-ethylene oxide) copolymers (SEO) and Li[N(SO2CF3)2] (LiTFSI). The molar ratio of Li to ethylene monomers, r, was varied from 0.02 to 0.10. The ionic conductivity of these electrolytes increases with molecular weight over the entire range of temperatures and r values examined. Preliminary data suggest that the salt diffusion coefficient also increases with increasing MW of PEO block.

  6. Human aldehyde dehydrogenase-catalyzed oxidation of ethylene glycol ether aldehydes.

    PubMed

    Gross, Aaron; Ong, Ta Ren; Grant, Rainer; Hoffmann, Todd; Gregory, Daniel D; Sreerama, Lakshmaiah

    2009-03-16

    Ethylene glycol ethers (EGEs) are primary alcohols commonly used as solvents in numerous household and industrial products. Exposure to EGEs has been correlated with delayed encephalopathy, metabolic acidosis, sub-fertility and spermatotoxicity in humans. In addition, they also cause teratogenesis, carcinogenesis, hemolysis, etc., in various animal models. Metabolism EGEs parallels ethanol metabolism, i.e., EGEs are first converted to 2-alkoxy acetaldehydes (EGE aldehydes) by alcohol dehydrogenases, and then to alkoxyacetic acids by aldehyde dehydrogenases (ALDHs). The acid metabolite of EGEs is considered responsible for toxicities associated with EGEs. The role of human ALDHs in EGE metabolism is not clear; accordingly, we have investigated the ability of five different human ALDHs (ALDH1A1, ALDH2, ALDH3A1, ALDH5A1 and ALDH9A1) to catalyze the oxidation of various EGE aldehydes. The EGE aldehydes used in this study were synthesized via Swern oxidation. All of the human ALDHs were purified from human cDNA clones over-expressing these enzymes in E. coli. The ALDHs tested, so far, differentially catalyze the oxidation of EGE aldehydes to their corresponding acids (K(m) values range from approximately 10 microM to approximately 20.0mM). As judged by V(max)/K(m) ratios, short-chain alkyl-group containing EGE aldehydes are oxidized to their acids more efficiently by ALDH2, whereas aryl- and long-chain alkyl-group containing EGE aldehydes are oxidized to their acid more efficiently by ALDH3A1. Given the product of ALDH-catalyzed reaction is toxic, this process should be considered as a bio-activation (toxification) process.

  7. Zinc oxide doped graphene oxide films for gas sensing applications

    SciTech Connect

    Chetna, Kumar, Shani; Chaudhary, S.; Kapoor, A.; Garg, A.; Chowdhuri, A.; Dhingra, V.

    2016-05-06

    Graphene Oxide (GO) is analogous to graphene, but presence of many functional groups makes its physical and chemical properties essentially different from those of graphene. GO is found to be a promising material for low cost fabrication of highly versatile and environment friendly gas sensors. Selectivity, reversibility and sensitivity of GO based gas sensor have been improved by hybridization with Zinc Oxide nanoparticles. The device is fabricated by spin coating of deionized water dispersed GO flakes (synthesized using traditional hummer’s method) doped with Zinc Oxide on standard glass substrate. Since GO is an insulator and functional groups on GO nanosheets play vital role in adsorbing gas molecules, it is being used as an adsorber. Additionally, on being exposed to certain gases the electric and optical characteristics of GO material exhibit an alteration in behavior. For the conductivity, we use Zinc Oxide, as it displays a high sensitivity towards conduction. The effects of the compositions, structural defects and morphologies of graphene based sensing layers and the configurations of sensing devices on the performances of gas sensors were investigated by Raman Spectroscopy, X-ray diffraction(XRD) and Keithley Sourcemeter.

  8. Non-invasive photoacoustic spectroscopic determination of relative endogenous nitric oxide and ethylene content stoichiometry during the ripening of strawberries Fragaria anannasa (Duch.) and avocados Persea americana (Mill.).

    PubMed

    Leshem, Y Y; Pinchasov, Y

    2000-08-01

    Employing non-invasive photoacoustic spectrometry, emissions of nitric oxide (NO) and ethylene in post-harvest strawberries and avocados were monitored. A clear-cut stoichiometric relationship was found between the two gases: unripe fruit manifesting high NO and low ethylene levels-the converse in ripe fruit. Findings are discussed in the light of putative control of ethylene-promoted fruit senescence by endogenous NO.

  9. Testing odorants recovery from a novel metallized fluorinated ethylene propylene gas sampling bag.

    PubMed

    Zhu, Wenda; Koziel, Jacek A; Cai, Lingshuang; Wright, Donald; Kuhrt, Fred

    2015-12-01

    Industry-standard Tedlar bags for odor sample collection from confined animal feeding operations (CAFOs) have been challenged by the evidence of volatile organic compound (VOC) losses and background interferences. Novel impermeable aluminum foil with a thin layer of fluorinated ethylene propylene (FEP) film on the surface that is in contact with a gas sample was developed to address this challenge. In this research, Tedlar and metallized FEP bags were compared for (a) recoveries of four characteristic CAFO odorous VOCs (ethyl mercaptan, butyric acid, isovaleric acid and p-cresol) after 30 min and 24 hr sample storage time and for (b) chemical background interferences. All air sampling and analyses were performed with solid-phase microextraction (SPME) followed by gas chromatography-mass spectroscopy (GC-MS). Mean target gas sample recoveries from metallized FEP bags were 25.9% and 28.0% higher than those in Tedlar bags, for 30 min and 24 hr, respectively. Metallized FEP bags demonstrated the highest p-cresol recoveries after 30-min and 24-hr storage, 96.1±44.5% and 44.8±10.2%, respectively, among different types of sampling bags reported in previous studies. However, a higher variability was observed for p-cresol recovery with metallized FEP bags. A 0% recovery of ethyl mercaptan was observed with Tedlar bags after 24-hr storage, whereas an 85.7±7.4% recovery was achieved with metallized FEP bags. Recoveries of butyric and isovaleric acids were similar for both bag types. Two major impurities in Tedlar bags' background were identified as N,N-dimethylacetamide and phenol, while backgrounds of metallized FEP bags were significantly cleaner. Reusability of metallized FEP bags was tested. Caution is advised when using polymeric materials for storage of livestock-relevant odorous volatile organic compounds. The odorants loss with storage time confirmed that long-term storage in whole-air form is ill advised. A focused short-term odor sample containment should be

  10. Revealing the Cytotoxicity of Residues of Phosphazene Catalysts Used for the Synthesis of Poly(ethylene oxide).

    PubMed

    Xia, Yening; Shen, Jizhou; Alamri, Haleema; Hadjichristidis, Nikos; Zhao, Junpeng; Wang, Yucai; Zhang, Guangzhao

    2017-09-01

    We herein report a case study on the toxicity of residual catalyst in metal-free polymer. Eight-arm star-like poly(ethylene oxide)s were successfully synthesized via phosphazene-catalyzed ring-opening polymerization of ethylene oxide using sucrose as an octahydroxy initiator. The products were subjected to MTT assay using human cancer cell lines (MDA-MB-231 and A2780). Comparison between the crude and purified products clearly revealed that the residual phosphazenium salts were considerably cytotoxic, regardless of the anionic species, and that the cytotoxicity of more bulky t-BuP4 salt was higher than that of t-BuP2 salt. Such results have therefore put forward the necessity for removal of the catalyst residues from PEO-based polymers synthesized through phosphazene catalysis for biorelated applications and for the development of less or nontoxic organocatalysts for such polymers.

  11. [Effect of sterilisation with formaldehyde, gamma irradiation and ethylene oxide on the properties of polyethylene joint replacement components].

    PubMed

    Fulín, P; Pokorný, D; Slouf, M; Vacková, T; Dybal, J; Sosna, A

    2014-01-01

    Each method of sterilisation has some effect on the structure and properties of UHMWPE and thus also on joint replacement longevity. This study was designed to compare, using objective methods of measurement, several kinds of sterilisation and to recommend the one which has the best prospect for making joint replacements last longer. Two groups of UHMWPE samples were tested. Group 1 included virgin GUR 1020 polyethylene, non-modified and non-sterilised (Meditech, Germany). Group 2 comprised of three sets of samples sterilised with formaldehyde, gamma irradiation and ethylene oxide, respectively. In both groups, physicochemical properties were assessed by infrared spectroscopy (IR), and the oxidation (OI) and trans-vinyl (VI) indices, which show the degree of oxidation of a material, were determined. Free-radical concentrations were measured by the method of electron spin resonance (ESR). The mechanical properties of each sample were studied using small punch tests (SPT) and testing microhardness (MH). Any change in mechanical properties can affect, to various degrees, the quality and longevity of a prosthetic joint. The samples sterilised by gamma irradiation showed higher values of both the OI (0.37) and the VI index (0.038) than the other samples (OI, 0.02 to 0.05 and VI, 0). Also, the free-radical concentration was detectable only in the gamma-sterilised sample. Values obtained for mechanical properties were as follows: peak load in the range of 58.48 N (gamma irradiation) to 59.60 N (ethylene oxide); ultimate load in the range of 46.69 N (gamma irradiation) to 57.50 N (ethylene oxide); ultimate displacement in the range of 4.29 mm (gamma irradiation) to 4.58 mm (virgin polyethylene and formaldehyde); and work to failure in the range of 185.18 mJ (gamma irradiation) to 205.89 mJ (virgin polyethylene). Microhardness values were obtained in the following ranges: 41.2 to 44.6 MPa (virgin polyethylene); 40.2 to 44.1 MPa (formaldehyde); 46.1 to 49.3 MPa (gamma

  12. Surface studies of gas sensing metal oxides.

    PubMed

    Batzill, Matthias; Diebold, Ulrike

    2007-05-21

    The relation of surface science studies of single crystal metal oxides to gas sensing applications is reviewed. Most metal oxide gas sensors are used to detect oxidizing or reducing gases and therefore this article focuses on surface reduction processes and the interaction of oxygen with these surfaces. The systems that are discussed are: (i) the oxygen vacancy formation on the surface of the ion conductor CeO(2)(111); (ii) interaction of oxygen with TiO(2) (both adsorption processes and the incorporation of oxygen into the TiO(2)(110) lattice are discussed); (iii) the varying surface composition of SnO(2)(101) and its consequence for the adsorption of water; and (iv) Cu modified ZnO(0001)-Zn surfaces and its interaction with oxygen. These examples are chosen to give a comprehensive overview of surface science studies of different kinds of gas sensing materials and to illustrate the potential that surface science studies have to give fundamental insight into gas sensing phenomena.

  13. Non-invasive ethylene quantification in attached fruit headspace at 1 ppb by gas chromatography - mass spectrometry.

    PubMed

    Pereira, Lara; Pujol, Marta; Garcia-Mas, Jordi; Phillips, Michael A

    2017-03-28

    Ethylene is a gaseous plant hormone involved in defense, adaptations to environmental stress, and fruit ripening. Its relevance to the latter makes its detection highly useful to physiologists interested in ripening onset. Produced as a sharp peak during the respiratory burst, ethylene is biologically active at tens of nL·L(-1) . Reliable quantification at such concentrations generally requires specialized instrumentation. Here we present a rapid, high sensitivity method for detecting ethylene in attached fruit using a conventional gas chromatography - mass spectrometry (GC-MS) system and in situ headspace collection chambers. We apply this method to melon (Cucumis melo L.), a unique species consisting of climacteric and non-climacteric varieties, with a high variation in the climacteric phenotype among climacteric types. Using a population of recombinant inbred lines (RILs) derived from highly climacteric ("Védrantais", cantalupensis type) and non-climacteric ("Piel de sapo", inodorus type) parental lines, we observed a significant variation for the intensity, onset, and duration of the ethylene burst during fruit ripening. Our method does not require concentration, sampling times over 1 h, or fruit harvest. We achieved a limit of detection of 0.41 ± 0.04 nL·L(-1) and a limit of quantification of 1.37 ± 0.13 nL·L(-1) with an analysis time of 2.6 min per sample. Validation of the analytical method indicated that linearity (>98%), precision (CV ≤ 2%), and sensitivity compared favorably with dedicated optical sensors. This study adds to evidence of the characteristic climacteric ethylene burst as a complex trait whose intensity in our RIL population lies along a continuum in addition to two extremes. This article is protected by copyright. All rights reserved.

  14. 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.

  15. Confinement effects on the crystallization of poly(ethylene oxide) nanotubes.

    PubMed

    Maiz, Jon; Martin, Jaime; Mijangos, Carmen

    2012-08-21

    In this work, we show the effects of nanoconfinement on the crystallization of poly(ethylene oxide) (PEO) nanotubes embedded in anodized aluminum oxide (AAO) templates. The morphological characteristics of the hollow 1D PEO nanostructures were evaluated by scanning electron microscopy (SEM). The crystallization of the PEO nanostructures and bulk was studied with differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD). The crystallization of PEO nanotubes studied by DSC is strongly influenced by the confinement showing a strong reduction in the crystallization temperature of the polymer. X-ray diffraction (XRD) experiments confirmed the isothermal crystallization results obtained by DSC, and studies carried out at low temperatures showed the absence of crystallites oriented with the extended chains perpendicular to the pore wall within the PEO nanotubes, which has been shown to be the typical crystal orientation for one-dimensional polymer nanostructures. In contrast, only planes oriented 33, 45, and 90° with respect to the plane (120) are arranged parallel to the pore's main axis, indicating preferential crystal growth in the direction of the radial component. Calculations based on classical nucleation theory suggest that heterogeneous nucleation prevails in the bulk PEO whereas for the PEO nanotubes a surface nucleation mechanism is more consistent with the obtained results.

  16. Covalent functionalization of graphene oxide with biocompatible poly(ethylene glycol) for delivery of paclitaxel.

    PubMed

    Xu, Zhiyuan; Wang, Song; Li, Yongjun; Wang, Mingwei; Shi, Ping; Huang, Xiaoyu

    2014-10-08

    Graphene oxide (GO), a novel 2D nanomaterial prepared by the oxidation of natural graphite, has been paid much attention in the area of drug delivery due to good biocompatibility and low toxicity. In the present work, 6-armed poly(ethylene glycol) was covalently introduced into the surface of GO sheets via a facile amidation process under mild conditions, making the modified GO, GO-PEG (PEG: 65 wt %, size: 50-200 nm), stable and biocompatible in physiological solution. This nanosized GO-PEG was found to be nontoxic to human lung cancer A549 and human breast cancer MCF-7 cells via cell viability assay. Furthermore, paclitaxel (PTX), a widely used cancer chemotherapy drug, was conjugated onto GO-PEG via π-π stacking and hydrophobic interactions to afford a nanocomplex of GO-PEG/PTX with a relatively high loading capacity for PTX (11.2 wt %). This complex could quickly enter into A549 and MCF-7 cells evidenced by inverted fluorescence microscopy using Fluorescein isothiocyanate as a probe, and it also showed remarkably high cytotoxicity to A549 and MCF-7 cells in a broad range of concentration of PTX and time compared to free PTX. This kind of nanoscale drug delivery system on the basis of PEGylated GO may find potential application in biomedicine.

  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. Volatile out gassing characteristics of highly filled ethylene vinyl acetate binder materials: Gas phase infra-red spectroscopy

    DOE PAGES

    Patel, Mogon; Bowditch, Martin; Jones, Ben; ...

    2012-12-08

    Gas phase Infra-red (IR) spectroscopy has been used to investigate volatile out gassing properties of highly filled poly (ethylene-co-vinyl acetate) materials. In these studies, a Scout-ENTM heated gas cell was interfaced to a vacuum FTIR spectrometer, and the quantification of evolved species was achieved through calibration of the gas cell with certified gas standards. The volatile out gassing properties were monitored as a function of time during storage at 75°C under vacuum conditions (< 1mbar). Acetic acid, carbon dioxide and water were identified as the major out gassing products through IR absorption peaks at 1797, 2354 and 3853 cm-1, respectively.more » We present a comparison of three highly filled poly (ethyleneco- vinyl acetate) resins.« less

  19. Volatile out gassing characteristics of highly filled ethylene vinyl acetate binder materials: Gas phase infra-red spectroscopy

    SciTech Connect

    Patel, Mogon; Bowditch, Martin; Jones, Ben; Netherton, David; Khan, Niaz; Letant, Sonia; Maxwell, Robert S.; Birdsell, Stephen A.

    2012-12-08

    Gas phase Infra-red (IR) spectroscopy has been used to investigate volatile out gassing properties of highly filled poly (ethylene-co-vinyl acetate) materials. In these studies, a Scout-ENTM heated gas cell was interfaced to a vacuum FTIR spectrometer, and the quantification of evolved species was achieved through calibration of the gas cell with certified gas standards. The volatile out gassing properties were monitored as a function of time during storage at 75°C under vacuum conditions (< 1mbar). Acetic acid, carbon dioxide and water were identified as the major out gassing products through IR absorption peaks at 1797, 2354 and 3853 cm-1, respectively. We present a comparison of three highly filled poly (ethyleneco- vinyl acetate) resins.

  20. Selenium and sulfur influence ethylene formation and alleviate cadmium-induced oxidative stress by improving proline and glutathione production in wheat.

    PubMed

    Khan, M Iqbal R; Nazir, Faroza; Asgher, Mohd; Per, Tasir S; Khan, Nafees A

    2015-01-15

    We have studied the influence of selenium (Se) and sulfur (S) in the protection of photosynthetic capacity of wheat (Triticum aestivum) against cadmium (Cd) stress. The involvement of ethylene and its interaction with proline and antioxidant metabolism in the tolerance of plants to Cd stress was evaluated. Application of Se or S alleviated Cd-induced oxidative stress by increasing proline accumulation as a result of increased activity of glutamyl kinase (GK) and decreased activity of proline oxidase (PROX). These nutrients also induced the activity of ATP-sulfurylase and serine acetyl transferase and the content of cysteine (Cys), a precursor for the synthesis of both reduced glutathione (GSH) and ethylene. Further, application of Se and S to plants under Cd stress reduced ethylene level and increased the activity of glutathione reductase (GR) and glutathione peroxidase (GPX), reduced oxidative stress and improved photosynthesis and growth. The involvement of ethylene in Se and S-mediated alleviation of Cd stress was substantiated with the use of ethylene biosynthesis inhibitor aminoethoxyvinylglycine (AVG). The use of AVG reversed the effects of Se and S on ethylene, content of proline and GSH and photosynthesis. The results suggested that Se and S both reversed Cd-induced oxidative stress by regulating ethylene formation, proline and GSH metabolism. Thus, Se or S-induced regulatory interaction between ethylene and proline and GSH metabolism may be used for the reversal of Cd-induced oxidative stress.

  1. 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

  2. Influence of ethylene glycol on CaCO 3 particles formation via carbonation in the gas-slurry system

    NASA Astrophysics Data System (ADS)

    Konopacka-łyskawa, Donata; Lackowski, Marcin

    2011-04-01

    Calcium carbonate precipitation was investigated in the gas-slurry system in the reaction of calcium hydroxide and carbon dioxide. The precipitation process was occurred in the presence of ethylene glycol (EG). The used organic additive changed the viscosity of reactive mixture, the solubility of carbon dioxide and the solubility of calcium carbonate which influence CaCO 3 precipitation conditions. The course of reaction was monitored by conductivity probe. The increase concentration of ethylene glycol in the reactive mixture caused higher CO 2 usage to achieve the end point of reaction. Calcium carbonate was precipitated as calcite and produced CaCO 3 particles formed agglomerates in all experiments. The size of obtained CaCO 3 particles decreased when the EG concentration increased from 0% to 15% (by vol.). The further increase of EG concentration in solution up to 20% resulted in an increase of the size of CaCO 3 particles.

  3. 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.

  4. The effect of plant cytokinin hormones on the production of ethylene, nitric oxide, and protein nitrotyrosine in ageing tobacco leaves.

    PubMed

    Wilhelmová, N; Fuksová, H; Srbová, M; Miková, D; Mýtinová, Z; Procházková, D; Vytásek, R; Wilhelm, J

    2006-01-01

    Transgenic plants with genetically increased or decreased levels of cytokinins were used to investigate the effect of cytokinin level on the production of ethylene, a plant hormone with suggested role in senescence, and the production of nitric oxide, potentially important signalling and regulatory molecule. The production of these gases was followed during the course of leaf development and senescence. The production of ethylene and nitric oxide is under genetic control of genes other than those involved in regulation of senescence. The difference in basic ethylene and NO levels in different tobacco cultivars was higher than their changes in senescence. The results of this study did not indicate a direct link between ethylene production and cytokinin levels. However, there was a decreased production of NO in senescent leaves. Low cytokinins level was associated with increased NO production during leaf development. Protein nitrotyrosine proved to be a better indicator of the reactive nitrogen species than measuring of the NO production. Higher nitrotyrosine concentrations were found in insoluble proteins than in the soluble ones, pointing to membrane proteins as the primary targets of the reactive nitrogen species. In plants with elevated cytokinin levels the content of nitrated proteins decreased both in soluble and insoluble fractions. This finding indicates an antioxidative function of cytokinins against reactive nitrogen species.

  5. Fundamentals of Mercury Oxidation in Flue Gas

    SciTech Connect

    JoAnn Lighty; Geoffrey Silcox; Constance Senior; Joseph Helble; Balaji Krishnakumar

    2008-07-31

    The objective of this project was to understand the importance of and the contribution of gas-phase and solid-phase coal constituents in the mercury oxidation reactions. The project involved both experimental and modeling efforts. The team was comprised of the University of Utah, Reaction Engineering International, and the University of Connecticut. The objective was to determine the experimental parameters of importance in the homogeneous and heterogeneous oxidation reactions; validate models; and, improve existing models. Parameters studied include HCl, NO{sub x}, and SO{sub 2} concentrations, ash constituents, and temperature. The results suggested that homogeneous mercury oxidation is below 10% which is not consistent with previous data of others and work which was completed early in this research program. Previous data showed oxidation above 10% and up to 100%. However, the previous data are suspect due to apparent oxidation occurring within the sampling system where hypochlorite ion forms in the KCl impinger, which in turn oxidized mercury. Initial tests with entrained iron oxide particles injected into a flame reactor suggest that iron present on fly ash particle surfaces can promote heterogeneous oxidation of mercury in the presence of HCl under entrained flow conditions. Using the data generated above, with homogeneous reactions accounting for less than 10% of the oxidation, comparisons were made to pilot- and full-scale data. The results suggest that heterogeneous reactions, as with the case of iron oxide, and adsorption on solid carbon must be taking place in the full-scale system. Modeling of mercury oxidation using parameters from the literature was conducted to further study the contribution of homogeneous pathways to Hg oxidation in coal combustion systems. Calculations from the literature used rate parameters developed in different studies, in some cases using transition state theory with a range of approaches and basis sets, and in other cases

  6. 21 CFR 868.1700 - Nitrous oxide gas analyzer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nitrous oxide gas analyzer. 868.1700 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1700 Nitrous oxide gas analyzer. (a) Identification. A nitrous oxide gas analyzer is a device intended to measure the concentration of nitrous...

  7. 21 CFR 868.1700 - Nitrous oxide gas analyzer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nitrous oxide gas analyzer. 868.1700 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1700 Nitrous oxide gas analyzer. (a) Identification. A nitrous oxide gas analyzer is a device intended to measure the concentration of nitrous...

  8. Enhanced Lithium Ion Transport in Poly(ethylene glycol) Diacrylate-Supported Solvate Ionogel Electrolytes via Chemically Cross-linked Ethylene Oxide Pathways.

    PubMed

    D'Angelo, Anthony J; Panzer, Matthew J

    2017-02-02

    Lithium-ion solvate ionic liquids (SILs), consisting of complexed Li(+) cations and a weakly basic anion, represent an emergent class of nonvolatile liquid electrolytes suitable for lithium-based electrochemical energy storage. In this report, solid-state, flexible solvate ionogel electrolytes are synthesized via UV-initiated free radical polymerization/cross-linking of poly(ethylene glycol) diacrylate (PEGDA) in situ within the [Li(G4)][TFSI] electrolyte, which is formed by an equimolar mixture of lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) and tetraglyme (G4). Ion diffusivity measurements reveal enhanced Li(+) diffusion in PEGDA-supported solvate ionogels, as compared to poly(methyl methacrylate)-supported gels that lack ethylene oxide chains. At 21 vol% PEGDA, a maximum Li(+) transport number of 0.58 and a room temperature ionic conductivity of 0.43 mS/cm have been achieved in a solvate ionogel electrolyte that exhibits an elastic modulus of 0.47 MPa. These results demonstrate the importance of polymer scaffold selection on solvate ionogel electrolyte performance for advanced lithium-based batteries.

  9. Fabrication and anti-fouling properties of photochemically and thermally immobilized poly(ethylene oxide) and low molecular weight poly(ethylene glycol) thin films.

    PubMed

    Wang, Hui; Ren, Jin; Hlaing, Aye; Yan, Mingdi

    2011-02-01

    Poly(ethylene oxide) (PEO) and low molecular weight poly(ethylene glycol) (PEG) were covalently immobilized on silicon wafers and gold films by way of the CH insertion reaction of perfluorophenyl azides (PFPAs) by either photolysis or thermolysis. The immobilization does not require chemical derivatization of PEO or PEG, and polymers of different molecular weights were successfully attached to the substrate to give uniform films. Microarrays were also generated by printing polymer solutions on PFPA-functionalized wafer or Au slides followed by light activation. For low molecular weight PEG, the immobilization was highly dependent on the quality of the film deposited on the substrate. While the spin-coated and printed PEG showed poor immobilization efficiency, thermal treatment of the PEG melt on PFPA-functionalized surfaces resulted in excellent film quality, giving, for example, a grafting density of 9.2×10(-4)Å(-2) and an average distance between grafted chains of 33Å for PEG 20,000. The anti-fouling property of the films was evaluated by fluorescence microscopy and surface plasmon resonance imaging (SPRi). Low protein adsorption was observed on thermally-immobilized PEG whereas the photoimmobilized PEG showed increased protein adsorption. In addition, protein arrays were created using polystyrene (PS) and PEG based on the differential protein adsorption of the two polymers. Copyright © 2010 Elsevier Inc. All rights reserved.

  10. FUNDAMENTALS OF MERCURY OXIDATION IN FLUE GAS

    SciTech Connect

    JoAnn S. Lighty; Geoffrey Silcox; Andrew Fry; Constance Senior; Joseph Helble

    2004-08-01

    The objective of this project is to understand the importance of and the contribution of gas-phase and solid-phase coal constituents in the mercury oxidation reactions. The project involves two experimental scales and a modeling effort. The team is comprised of University of Utah, Reaction Engineering International, and University of Connecticut. The objective is to determine the experimental parameters of importance in the homogeneous and heterogeneous oxidation reactions; validate models; and, improve existing models. Parameters to be studies include HCl, NOx, and SO{sub 2} concentrations, ash constituents, and temperature. This report summarizes Year 1 results for the experimental and modeling tasks. Experiments in the drop tube are just beginning and a new, speciated mercury analyzer is up and running. A preliminary assessment has been made for the drop tube experiments using the existing model of gas-phase kinetics.

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

    PubMed

    Peter, Matthias; Marks, Tobin J

    2015-12-09

    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.

  12. 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.

  13. 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

  14. Small angle x-ray scattering study of the interaction of poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) triblock copolymers with lipid bilayers.

    SciTech Connect

    Firestone, M. A.; Wolf, A. C.; Seifert, S.; Univ. Chicago

    2003-11-01

    The relationship between molecular architecture and the nature of interactions with lipid bilayers has been studied for a series of poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers using small-angle X-ray scattering (SAXS) and thermal analysis (differential scanning calorimetry, DSC). The number of molecular repeat units in the hydrophobic poly(propylene oxide), PPO, block has been found to be a critical determinant of the nature of triblock copolymer-lipid bilayer association. For dimyristoyl-sn-glycero-3-phosphocholine (DMPC)-based biomembrane structures, polymers possessing a PPO chain length commensurate with the acyl chain dimensions of the lipid bilayer yield highly ordered, swollen lamellar structures consistent with well-integrated (into the lipid bilayer) PPO blocks. Triblock copolymers of lesser PPO chain length yield materials with structural characteristics similar to a simple dispersion of DMPC in water. Increasing the concentration (from 4 to 12 mol %) of well-integrated triblock copolymers enhances the structural ordering of the lamellar phase, while concentrations exceeding 16 mol % result in the formation of a hexagonal phase. Examination of temperature-induced changes in the structure of these mesophases (complex fluids) reveals that if the temperature is reduced sufficiently, all compositions exclude polymer and thus exhibit the characteristic SAXS pattern for hydrated DMPC bilayers. Increasing the temperature promotes better insertion of the polymers possessing PPO chain lengths sufficient for membrane insertion. No temperature-induced structural changes are observed in compositions prepared with PEO-PPO-PEO polymers that feature PPO length insufficient to permit full incorporation into the lipid bilayer.

  15. Increasing the repeating units of ethylene glycol-based dimethacrylates directed toward reduced oxidative stress and co-stimulatory factors expression in human monocytic cells.

    PubMed

    Tamura, Atsushi; Fukumoto, Izumi; Yui, Nobuhiko; Matsumura, Mitsuaki; Miura, Hiroyuki

    2015-03-01

    The ethylene glycol-based dimethacrylates are commonly used in biomaterials and dental restorative materials as a cross-linking agent. In this study, toxic effect of triethylene glycol dimethacrylate (TEGDMA) and poly(ethylene glycol) dimethacrylates (PEG-DMAs) with various ethylene glycol repeating units was investigated in terms of cytotoxicity, oxidative stress, and the expression of co-stimulatory factors in human leukemia cell line (THP-1 cells) to verify the effect of ethylene glycol repeating units. Note that the 1-octanol/water partition coefficient of PEG-based dimethacrylates decreased with increasing the ethylene glycol repeating units, indicating that the hydrophilicity of PEG-DMAs increased with ethylene glycol repeating units. The toxic effect of PEG-DMAs such as cytotoxicity, oxidative stress, and the expression of CD86 in treated THP-1 cells are reduced with increasing the ethylene glycol repeating units in PEG-DMAs. However, the expression of CD54 in treated THP-1 cells was not influenced with the ethylene glycol repeating units and the maximal expression level of CD54 was observed at the concentration range of 2-4 mM for all samples. Accordingly, hydrophilic character of PEG-DMAs with long ethylene glycol chains definitely alleviates the some toxic aspect of PEG-based DMAs. This finding would provide important insight into the design of new biomaterials and dental materials with superior biocompatibility. © 2014 Wiley Periodicals, Inc.

  16. On the interactions between poly(ethylene oxide) and graphite oxide: A comparative study by different computational methods

    NASA Astrophysics Data System (ADS)

    Garcia-Yoldi, I.; Álvarez, F.; Colmenero, J.

    2013-03-01

    The aim of this work is to investigate polymer...substrate interactions for a polymer nanocomposite material: poly(ethylene oxide) (PEO) confined in graphite oxide (GO). Six discrete and simplified models (one for PEO and five for GO) have been chosen in order to reproduce the most likely PEO...GO interactions. Twelve potential interaction energy curves have been built using the models and curve minima have been optimized using the 2nd order Møller-Plesset perturbation theory (MP2)/6-31+G(d) method. The intermolecular interactions have been analyzed in terms of distances, stabilities, and bond critical points properties revealing several dispersion assisted π-interactions and the most stable hydrogen bond interaction between the hydrogen of the GO hydroxyl groups and the oxygen of the PEO. MP2 results have been compared with five density functionals developed by Truhlar and Zhao (M05, M05-2X, M05-2X, M06-HF, and M06-L).

  17. Industrywide studies report: a walk through survey of Ross Laboratories (Division of Abbott Laboratories), Columbus, Ohio. [Ethylene oxide

    SciTech Connect

    Greife, A.; Steenland, K.

    1985-10-02

    A walk-through survey was conducted at Ross Laboratories, a Division of Abbott Laboratories, Columbus, Ohio in August, 1985. The purpose of the survey was to determine the feasibility of including the facility in a NIOSH industry wide mortality/industrial hygiene survey of ethylene oxide. The facility produced infant formula and infant related products, including nipples. The company had a full time nurse on the first and second shifts. A physician was available on a contract basis. New employees were given preemployment physicals. Employees received annual physicals until 1982 after which they became optional. The physicals did not include any components relating to ethylene-oxide exposure. The authors conclude that the personnel records are not adequate to identify a cohort of exposed individuals at the facility. The facility will not be included in the NIOSH study.

  18. Synthesis of eight-shaped poly(ethylene oxide) by the combination of Glaser coupling with ring-opening polymerization.

    PubMed

    Wang, Guowei; Fan, Xiaoshan; Hu, Bin; Zhang, Yannan; Huang, Junlian

    2011-10-18

    The eight-shaped poly(ethylene oxide) (PEO) is synthesized by a combination of Glaser coupling with ring-opening polymerization (ROP). Firstly, the star-shaped (PEO-OH)(4) is synthesized by ROP of ethylene oxide (EO) using pentaerythritol as an initiator and diphenylmethyl potassium (DPMK) as a deprotonated agent, and then the alkyne group is introduced onto the PEO arm-end to give (PEO-Alkyne)(4) in a NaH/tetrahydrofuran (THF) system. The intramolecular cyclization is carried out by a Glaser coupling reaction in a pyridine/CuBr/N,N,N',N",N"-pentamethyldiethylenetriamine (PMDETA) system at room temperature in an air atmosphere, and eight-shaped PEO was formed with high efficiency (almost 100%). The target polymers and intermediates were well characterized by SEC, MALDI-TOF MS, (1)H NMR and FT-IR in detail. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Mocvd of Tin Oxide for Gas Sensors.

    NASA Astrophysics Data System (ADS)

    Weglicki, Peter Stanislaw

    1990-01-01

    Available from UMI in association with The British Library. Requires signed TDF. Thin films of a wide variety of materials can be produced using an assortment of physical and chemical techniques. Such techniques are reviewed and compared, with particular reference to the deposition of tin oxide films. In the present study, MOCVD (Metal organic chemical vapour deposition) was used to grow thin films of tin oxide from dibutyltin diacetate precursor on a variety of substrates. A series of reactor prototypes were developed in accordance with specific requirements of reproducibility and process control. The evolution of the designs leading to the final working system is detailed. The theory of MOCVD is given with particular reference to the reactor used in this project. The effects of various deposition parameters on tin oxide film growth rates were investigated, and the results are discussed with reference to the deposition kinetics in the system. Films were characterised by optical interferometry, optical and electron microscopy, X-ray diffraction, Rutherford backscattering and electrical measurements. The films were generally uniform, conducting and polycrystalline, and were comprised of very small grains, resulting in a high density. A specific application of metal oxide materials is in solid state gas sensors, which are available in various forms and operate according to different mechanisms. These are compared and a detailed account is given on the theory of operation of surface conductivity modulated devices. The application of such devices based on tin oxide in thin film form was investigated in the present work. The prepared sensor samples were comprised of very small grains, resulting in a high density. The observation that preferred (310) orientation occured in thicker films, can be attributed to dendritic growth. The sensors generally showed response to numerous reducing gas ambients, although there was evidence of a degree of selectivity against methane

  20. 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.

  1. Electrode-Impregnable and Cross-Linkable Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) Triblock Polymer Electrolytes with High Ionic Conductivity and a Large Voltage Window for Flexible Solid-State Supercapacitors.

    PubMed

    Han, Jae Hee; Lee, Jang Yong; Suh, Dong Hack; Hong, Young Taik; Kim, Tae-Ho

    2017-10-04

    We present cross-linkable precursor-type gel polymer electrolytes (GPEs) that have large ionic liquid uptake capability, can easily penetrate electrodes, have high ion conductivity, and are mechanically strong as high-performance, flexible all-solid-state supercapacitors (SC). Our polymer precursors feature a hydrophilic-hydrophobic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock main-chain structure and trifunctional silane end groups that can be multi-cross-linked with each other through a sol-gel process. The cross-linked solid-state electrolyte film with moderate IL content (200 wt %) shows a well-balanced combination of excellent ionic conductivity (5.0 × 10(-3) S cm(-1)) and good mechanical stability (maximum strain = 194%). Moreover, our polymer electrolytes have various advantages including high thermal stability (decomposition temperature > 330 °C) and the capability to impregnate electrodes to form an excellent electrode-electrolyte interface due to the very low viscosity of the precursors. By assembling our GPE-impregnated electrodes and solid-state GPE film, we demonstrate an all-solid-state SC that can operate at 3 V and provides an improved specific capacitance (112.3 F g(-1) at 0.1 A g(-1)), better rate capability (64% capacity retention until 20 A g(-1)), and excellent cycle stability (95% capacitance decay over 10 000 charge/discharge cycles) compared with those of a reference SC using a conventional PEO electrolyte. Finally, flexible SCs with a high energy density (22.6 W h kg(-1) at 1 A g(-1)) and an excellent flexibility (>93% capacitance retention after 5000 bending cycles) can successfully be obtained.

  2. The effect of salts on the micellization temperature of aqueous poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) solutions and the dissolution rate and water diffusion coefficient in their corresponding gels.

    PubMed

    Anderson, Brian C; Cox, Suzan M; Ambardekar, Amar V; Mallapragada, Surya K

    2002-01-01

    Studies were performed to examine the effect of ionic salts on phase transitions, dissolution rates, and diffusion coefficients of water in gels of poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) with polymer concentrations ranging from 22 to 32% w/w and salt concentrations ranging from 0 to 1.5% w/w. Salts tested include Na(3)PO(4), Na(2)SO(4), Na(2)HPO(4), NaH(2)PO(4), NaCH(3)CO(2), NaCl, and KI. Micellization transition temperatures were obtained using differential scanning calorimetry. The dissolution rates were obtained by measurement of the surface erosion rates, and diffusion coefficients were obtained by using a method to analyze the intrusion of water into the aqueous gels. It was found that salts had no effect on the dissolution rate of the polymer gels into deionized water. However, when the salt concentration in the aqueous dissolution media was adjusted to match the concentration in the gels, the dissolution rate of the polymer gel decreased with increasing salt concentration. The salts also had a profound effect on the critical micellization temperature (CMT) and the diffusion coefficient of water within the gel. The diffusion coefficient and CMT decreased in the presence of salts. The magnitude of these effects was comparable to their placement on the Hofmeister, or lyotropic series for salts. The effects of polymer and salt concentrations on the CMT were quantified, and a single correlation was proposed to predict the micellization temperatures for a wide range of salt and polymer concentrations. Copyright 2002 Wiley-Liss, Inc.

  3. Mortality study update of ethylene oxide workers in chemical manufacturing: a 15 year update.

    PubMed

    Swaen, Gerard M H; Burns, Carol; Teta, Jane M; Bodner, Kenneth; Keenan, Dave; Bodnar, Catherine M

    2009-06-01

    To investigate the long-term mortality patterns of workers with past exposure to ethylene oxide (EO). We redefined and updated a cohort of male workers employed in industrial facilities where EO was produced or used. All 2063 men were employed between 1940 and the end of 1988 and were observed for mortality through 2003. Cause specific Standardized Mortality Ratios were calculated. Internal analyses were made by applying Cox proportional hazards models to the data. No indications were found for excess cancer risks from EO exposures, including the lymphohematopoietic malignancies. There were 11 leukemia deaths and 11.8 expected and 12 non-Hodgkin lymphoma deaths and 11.5 expected. Proportional hazards modeling for all cause, leukemia and lymphoid malignancies mortality revealed no trends or associations with cumulative exposure. Despite the relatively high EO exposures in the past and extensive mortality follow-up, the cause specific mortality rates are comparable with those of the general US population. The Standardized Mortality Ratio analyses and the proportional hazards modeling for all cause mortality, leukemia and lymphoid malignancies mortality do not indicate exposure related effects in this cohort.

  4. Occupational exposure to ethylene oxide. Relation between in vivo dose and exposure dose.

    PubMed

    Osterman-Golkar, S; Bergmark, E

    1988-12-01

    As a basis for risk estimations for ethylene oxide (EtO) exposure and for the establishment of occupational exposure limits in work environments it is important to know the ratio between the in vivo dose and the exposure dose of this compound. For an assessment of this ratio, data on hemoglobin adduct levels in occupationally exposed workers and exposure levels in the work environment have been collected. The in vivo dose is directly proportional to the product of the uptake and retention time (1/lambda) of EtO in the body. The rate of clearance (lambda) of EtO has been calculated for individual workers from adduct levels and estimated EtO uptake. The wide range of lambda values found (approximately 1-65 h-1) can only partly be ascribed to a true variation between individuals with respect to clearance rates. One uncertainty results from the difficulties to estimate EtO uptake. A better estimate of lambda (approximately 3 h-1) is probably derived from the measurements of environmental and instantaneous blood concentrations of EtO in exposed workers by Brugnone et al [Int Arch Occup Environ Health 58 (1986) 105-112].

  5. Risk assessment and oncodynamics of ethylene oxide as related to occupational exposure.

    PubMed

    Beliles, R P; Parker, J C

    1987-09-01

    Two rat inhalation bioassays have been integrated into the risk assessment on the carcinogenicity of ethylene oxide (EO). The carcinogenic findings as well as relevant metabolism and pharmacokinetic data are reviewed. Brain tumors were selected as the endpoint for the assessment of risk because of the indication that adverse effects on the nervous system, related to EO exposure, were consistent across species. Two methods, time-exposure concentration product and area under the plasma concentration-time curve (AUC) are used as a basis for calculating effective dose. Scaling of the dose to man from both rat and dog is explored based on pharmacokinetic studies. Two different mathematical risk extrapolation models, the probit and the multi-stage, are used to estimate the cancer risk for daily exposures to EO of 1.8 microgram/liter over a working lifetime. The use of AUC as a basis for dose from a daily exposure of 1.8 microgram/liter over a working lifetime gives the higher risk rates (90-142/10,000 workers). The implication of the simulated dose using plasma concentrations versus the time-concentration product approach is discussed in relation to threshold effects.

  6. Quantitative cancer risk assessment for ethylene oxide inhalation in occupational settings.

    PubMed

    Valdez-Flores, Ciriaco; Sielken, Robert L; Teta, M Jane

    2011-10-01

    The estimated occupational ethylene oxide (EO) exposure concentrations corresponding to specified extra risks are calculated for lymphoid mortality as the most appropriate endpoint, despite the lack of a statistically significant exposure-response relationship. These estimated concentrations are for occupational exposures--40 years of occupational inhalation exposure to EO from age 20 to age 60 years. The estimated occupational inhalation exposure concentrations (ppm) corresponding to specified extra risks of lymphoid mortality to age 70 years in a population of male and female EO workers are based on Cox proportional hazards models of the most recent updated epidemiology cohort mortality studies of EO workers and a standard life-table calculation. An occupational exposure at an inhalation concentration of 2.77 ppm EO is estimated to result in an extra risk of lymphoid mortality of 4 in 10,000 (0.0004) in the combined worker population of men and women from the two studies. The corresponding estimated concentration decreases slightly to 2.27 ppm when based on only the men in the updated cohorts combined. The difference in these estimates reflects the difference between combining all of the available data or focusing on only the men and excluding the women who did not show an increase in lymphoid mortality with EO inhalation exposure. The results of sensitivity analyses using other mortality endpoints (all lymphohematopoietic tissue cancers, leukemia) support the choice of lymphoid tumor mortality for estimation of extra risk.

  7. Biological monitoring to assess dermal exposure to ethylene oxide vapours during an incidental release.

    PubMed

    Boogaard, Peter J; van Puijvelde, Mathieu J P; Urbanus, Jan H

    2014-12-15

    During a short incident in an ethylene oxide (EO) producing plant, EO vapour was released under high pressure. Operators wore full respiratory protection during repairs to fix the leak. To check the adequacy of the applied personal protective equipment and to address concerns about potential dermal exposure and subsequent uptake of EO, biological monitoring was applied by determination of the haemoglobin adducts of EO in blood. Based on the results of the biomonitoring, a risk assessment of dermal exposure to EO vapour was made. Calculations to estimate dermal exposure, based on two recently published models and using the relevant physical-chemical properties of EO, indicate that the dermal contribution to total exposure is expected to be negligible under normal operating circumstances. However, the models indicate that under accidental circumstances of product spillage, when high air concentrations can build up quickly and where incident response is conducted under respiratory protection with independently supplied air, the systemic exposure resulting from dermal absorption may reach levels of concern. The model estimates were compared to the actual biomonitoring data in the operators involved in the accidental release of EO vapour. The results suggest that when incidental exposures to high EO vapour concentrations (several thousand ppm) occur during periods in excess of 20-30 min, additional risk management measures, such as wearing chemical impervious suits, should be considered to control dermal uptake of EO. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  8. Ethylene oxide cancer risk assessment based on epidemiological data: application of revised regulatory guidelines.

    PubMed

    Teta, M J; Sielken, R L; Valdez-Flores, C

    1999-12-01

    Ethylene oxide (EO) research has significantly increased since the 1980s, when regulatory risk assessments were last completed on the basis of the animal cancer chronic bioassays. In tandem with the new scientific understanding, there have been evolutionary changes in regulatory risk assessment guidelines, that encourage flexibility and greater use of scientific information. The results of an updated meta-analysis of the findings from 10 unique EO study cohorts from five countries, including nearly 33,000 workers, and over 800 cancers are presented, indicating that EO does not cause increased risk of cancers overall or of brain, stomach or pancreatic cancers. The findings for leukemia and non-Hodgkin's lymphoma (NHL) are inconclusive. Two studies with the requisite attributes of size, individual exposure estimates and follow up are the basis for dose-response modeling and added lifetime risk predictions under environmental and occupational exposure scenarios and a variety of plausible alternative assumptions. A point of departure analysis, with various margins of exposure, is also illustrated using human data. The two datasets produce remarkably similar leukemia added risk predictions, orders of magnitude lower than prior animal-based predictions under conservative, default assumptions, with risks on the order of 1 x 10(-6) or lower for exposures in the low ppb range. Inconsistent results for "lymphoid" tumors, a non-standard grouping using histologic information from death certificates, are discussed. This assessment demonstrates the applicability of the current risk assessment paradigm to epidemiological data.

  9. 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.

  10. 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.

  11. FTIR assessment of poly(ethylene oxide) irradiated in solid state, melt and aqeuous solution

    NASA Astrophysics Data System (ADS)

    Pucić, Irina; Jurkin, Tanja

    2012-09-01

    FTIR spectroscopy was used to study poly(ethylene oxide), PEO, irradiated in solid and molten aggregate states and as aqueous solutions of various concentrations. The changes in shape and width of -C-O-C- complex absorption intensities at around 1112 cm-1 were the most prominent. On irradiation of solid samples in contact with air shrinking of -C-O-C- complex and increase in its absorption intensities indicated predominant degradation. Crosslinking prevailed on irradiation of molten PEO and of its aqueous solutions in nitrogen atmosphere and manifested itself as widening of -C-O-C- absorption and decrease of corresponding intensities. Partial or complete merging of CH2 wagging vibrations at 1342 cm-1 and 1360 cm-1 that are characteristic of crystalline PEO into a single absorption at around 1350 cm-1 indicated amorphization what was observed for samples that had reduced degree of crystallinity determined by differential scanning calorimetry. DSC could not discriminate between degradation and crosslinking while the changes in width and shape of -C-O-C- complex were independent of the changes in crystallinity. Comparison of FTIR spectra of the same PEO samples obtained as thin film and as KBr pellets revealed that pellet preparation results in a number of spectral artefacts.

  12. Electrospinning an essential oil: cinnamaldehyde enhances the antimicrobial efficacy of chitosan/poly(ethylene oxide) nanofibers.

    PubMed

    Rieger, Katrina A; Schiffman, Jessica D

    2014-11-26

    Due to the persistent spread of antibiotic resistance, commercial antibiotic treatments are proving ineffective. Cinnamaldehyde (CA), a volatile essential oil, eradicates pathogens non-specifically. However, the ability to incorporate essential oils into nanofiber mats has not yet been demonstrated, and, only six studies have electrospun two immiscible phases. Here, CA (0.5 and 5.0%) was incorporated into chitosan/poly(ethylene oxide) (PEO) solutions that were successfully electrospun into mats with ∼ 50 nm fiber diameters. Solid-state NMR results corroborated with release studies wherein the 5.0% CA mats released a statistically higher amount of CA-liquid (545% more) and CA-vapor (279% more) than the 0.5% CA mats. In time dependent cytotoxicity studies, the intrinsic antibacterial activity of chitosan along with the quick release of CA enabled high inactivation rates against Escherichia coli and Pseudomonas aeruginosa. For the first time we have demonstrated chitosan/CA/PEO nanofiber mats can serve as CA delivery vehicles that potentially eradicate pseudomonas infections. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Ethylene oxide dose and dose-rate effects in the mouse dominant-lethal test

    SciTech Connect

    Generoso, W.M.; Cain, K.T.; Hughes, L.A.; Sega, G.A.; Braden, P.W.; Gosslee, D.G.; Shelby, M.D.

    1986-01-01

    In the dose-response study, male mice were exposed by inhalation to ethylene oxide (EtO) for 4 consecutive days. Mice were exposed for 6 hr per day to 300 ppm, 400 ppm, or 500 ppm EtO for a daily total of 1800, 2400, or 3000 ppm X hr (total exposures of 7200, 9600 and 12,000 ppm X hr), respectively. In the dose-rate study, mice were given a total exposure of 1800 ppm X hr per day, also for 4 consecutive days, delivered either at 300 ppm in 6 hr, 600 ppm in 3 hr, or 1200 ppm in 1.5 hr. Quantitation of dominant-lethal responses was made on matings involving sperm exposed as late spermatids and early spermatozoa, the most sensitive stages to EtO. In the dose-response study, a dose-related increase in dominant-lethal mutations was observed, the dose-response curve proved to be nonlinear. In the dose-rate study, increasing the exposure concentrations resulted in increased dominant-lethal responses.

  14. On the Electrical Conductivity of Poly(vinylchloride)/poly(ethylene Oxide) Blends

    NASA Astrophysics Data System (ADS)

    Nasr, G. M.; El-Wahab, S. M. Abd; El-Athem, A. Abd

    2013-03-01

    Physical blending of different polymers is a very popular, simple and economical method of preparing composite with desirable and useful properties. The electrical conductivity of blends of amorphous poly(vinyl chloride) (PVC) with semicrystalline poly(ethylene oxide) (PEO) in the form of thin films has been measured by studying the I-V characteristics at room temperature and temperature dependence of the sample conductivity. The results are presented in the form of I-V characteristics and analysis has been made by interpretation of Poole Frenkel, Fowler-Nordheim and Schottky-Richardson plots. The analysis of these results suggests that Schottky - Richardson mechanism are primarily responsible for the observed conduction. Meanwhile, the percolation concentration of PEO in PVC matrix was found to be round 10%. Furthermore, the mechanism of electrical transport in this system is examined in temperature range 300-350K. The temperature dependence of conductivity gives evidence for the charge carriers transport mechanism via the occurred agreement of experimental results with the employed hopping models.

  15. Modulation of interaction forces between bilayers exposing short-chained ethylene oxide headgroups.

    PubMed Central

    Kuhl, T L; Leckband, D E; Lasic, D D; Israelachvili, J N

    1994-01-01

    The use of liposomes as drug delivery systems has been limited by their rapid clearance from circulation by the mononuclear phagocyte system. Recent studies have found that circulation times can be greatly enhanced by incorporating a small amount of modified lipids whose headgroups are derivatized with a bulky water soluble polymeric chain of poly ethylene oxide. We report here a systematic study using the Surface Forces Apparatus to measure directly the interactions between two phosphatidyl ethanolamine lipid bilayers, exposing this polymeric headgroup at different concentrations in the bilayer. We found that the force becomes repulsive at all separations and that the thickness of the steric barrier could be controlled easily by adjusting the concentration of the modified lipids. Equilibrium force profiles were measured that were reversible and largely insensitive to changes in electrolyte concentration and temperature. The results have enabled the Dolan and Edwards theory for the steric forces of low coverage polymer surfaces and the Alexander de Gennes theory for high coverage surfaces to be tested, and both were found to apply. We conclude that these simple theories can be used to model the interactions of surprisingly short segments and, hence, apply to such systems as lipids with bulky headgroups and liposomes containing a sterically stabilizing polymer. PMID:8061197

  16. 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.

  17. 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).

  18. Study of Polydiacetylene-Poly (Ethylene Oxide) Electrospun Fibers Used as Biosensors

    PubMed Central

    Alam, A K M Mashud; Yapor, Janet P.; Reynolds, Melissa M.; Li, Yan Vivian

    2016-01-01

    Polydiacetylene (PDA) is an attractive conjugated material for use in biosensors due to its unique characteristic of undergoing a blue-to-red color change in response to external stimuli. 10,12-Pentacosadiynoic acid (PCDA) and poly (ethylene oxide) (PEO) were used in this study to develop fiber composites via an electrospinning method at various mass ratios of PEO to PCDA, solution concentrations, and injection speeds. The PEO-PDA fibers in blue phase were obtained via photo-polymerization upon UV-light irritation. High mass ratios of PEO to PCDA, low polymer concentrations of spinning solution, and low injection speeds promoted fine fibers with small diameters and smooth surfaces. The colorimetric transition of the fibers was investigated when the fibers were heated at temperatures ranging from 25 °C to 120 °C. A color switch from blue to red in the fibers was observed when the fibers were heated at temperatures greater than 60 °C. The color transition was more sensitive in the fibers made with a low mass ratio of PEO to PCDA due to high fraction of PDA in the fibers. The large diameter fibers also promoted the color switch due to high reflectance area in the fibers. All of the fibers were analyzed using Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) and compared before and after the color change occurred. The colorimetric transitional mechanism is proposed to occur due to conformational changes in the PDA macromolecules. PMID:28773326

  19. Study of Polydiacetylene-Poly (Ethylene Oxide) Electrospun Fibers Used as Biosensors.

    PubMed

    Alam, A K M Mashud; Yapor, Janet P; Reynolds, Melissa M; Li, Yan Vivian

    2016-03-16

    Polydiacetylene (PDA) is an attractive conjugated material for use in biosensors due to its unique characteristic of undergoing a blue-to-red color change in response to external stimuli. 10,12-Pentacosadiynoic acid (PCDA) and poly (ethylene oxide) (PEO) were used in this study to develop fiber composites via an electrospinning method at various mass ratios of PEO to PCDA, solution concentrations, and injection speeds. The PEO-PDA fibers in blue phase were obtained via photo-polymerization upon UV-light irritation. High mass ratios of PEO to PCDA, low polymer concentrations of spinning solution, and low injection speeds promoted fine fibers with small diameters and smooth surfaces. The colorimetric transition of the fibers was investigated when the fibers were heated at temperatures ranging from 25 °C to 120 °C. A color switch from blue to red in the fibers was observed when the fibers were heated at temperatures greater than 60 °C. The color transition was more sensitive in the fibers made with a low mass ratio of PEO to PCDA due to high fraction of PDA in the fibers. The large diameter fibers also promoted the color switch due to high reflectance area in the fibers. All of the fibers were analyzed using Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) and compared before and after the color change occurred. The colorimetric transitional mechanism is proposed to occur due to conformational changes in the PDA macromolecules.

  20. Adhesion mapping of chemically modified and poly(ethylene oxide)-grafted glass surfaces

    PubMed Central

    Jogikalmath, G.; Stuart, J.K.; Pungor, A.; Hlady, V.

    2012-01-01

    Two-dimensional mapping of the adhesion pull-off forces was used to study the origin of surface heterogeneity in the grafted poly(ethylene oxide) (PEO) layer. The variance of the pull-off forces measured over the μm-sized regions after each chemical step of modifying glass surfaces was taken to be a measure of the surface chemical heterogeneity. The attachment of γ-glycidoxypropyltrimethoxy silane (GPS) to glass decreased the pull-off forces relative to the clean glass and made the surface more uniform. The subsequent hydrolysis of the terminal epoxide groups resulted in a larger surface heterogeneity which was modeled by two populations of the terminal hydroxyl groups, each with its own distribution of adhesion forces and force variance. The activation of the hydroxyls with carbonyldiimmidazole (CDI) healed the surface and lowered its adhesion, however, the force variance remained rather large. Finally, the grafting of the α,ω-diamino poly(ethyleneoxide) chains to the CDI-activated glass largely eliminated adhesion except at a few discrete regions. The adhesion on the PEO grafted layer followed the Poisson distribution of the pull-off forces. With the exception of the glass surface, a correlation between the water contact angles and the mean pull-off forces measured with the Si3N4 tip surfaces was found for all modified glass surfaces. PMID:22267896

  1. Isothermal Crystallization of Poly(ethylene oxide) / Single Walled Carbon Nanotube Nanocomposites

    NASA Astrophysics Data System (ADS)

    Lorenzo, Arnaldo; Chatterjee, Tirtha; Krishnamoorti, Ramanan

    2011-03-01

    The isothermal crystallization behavior of poly(ethylene oxide)/single walled carbon nanotubes (PEO/SWNT) nanocomposites were studied with a focus on the overall crystallization kinetics and the morphological evolution of PEO using differential scanning calorimetry and in-situ small angle x-ray scattering measurements, respectively. The overall crystallization process of the PEO was strongly affected by lithium dodecyl sulfate (LDS) stabilized carbon nanotubes. Further, analysis of the overall crystallization kinetics showed that the PEO chains were topologically constrained by the presence of LDS with an increased energy barrier associated with nucleation and crystal growth, and the nanotubes further act as a barrier to chain transport or enhance the LDS action on the PEO chains. The energy penalty and diffusional barrier to chain transport in the nanocomposites disrupt the PEO crystal helical conformation. This destabilization leads to formation of thinner crystal lamellae and suggests that the crystallization kinetics is primarily controlled by the growth process. This study is particularly interesting considering the suppression of the PEO crystallinity in presence of small amounts of Lithium ion based surfactant and carbon nanotubes.

  2. 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. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Integrating nitric oxide into salicylic acid and jasmonic acid/ ethylene plant defense pathways.

    PubMed

    Mur, Luis A J; Prats, Elena; Pierre, Sandra; Hall, Michael A; Hebelstrup, Kim H

    2013-01-01

    Plant defense against pests and pathogens is known to be conferred by either salicylic acid (SA) or jasmonic acid (JA)/ethylene (ET) pathways, depending on infection or herbivore-grazing strategy. It is well attested that SA and JA/ET pathways are mutually antagonistic allowing defense responses to be tailored to particular biotic stresses. Nitric oxide (NO) has emerged as a major signal influencing resistance mediated by both signaling pathways but no attempt has been made to integrate NO into established SA/JA/ET interactions. NO has been shown to act as an inducer or suppressor of signaling along each pathway. NO will initiate SA biosynthesis and nitrosylate key cysteines on TGA-class transcription factors to aid in the initiation of SA-dependent gene expression. Against this, S-nitrosylation of NONEXPRESSOR OF PATHOGENESIS-RELATED PROTEINS1 (NPR1) will promote the NPR1 oligomerization within the cytoplasm to reduce TGA activation. In JA biosynthesis, NO will initiate the expression of JA biosynthetic enzymes, presumably to over-come any antagonistic effects of SA on JA-mediated transcription. NO will also initiate the expression of ET biosynthetic genes but a suppressive role is also observed in the S-nitrosylation and inhibition of S-adenosylmethionine transferases which provides methyl groups for ET production. Based on these data a model for NO action is proposed but we have also highlighted the need to understand when and how inductive and suppressive steps are used.

  4. Reduced-mobility layers with high internal mobility in poly(ethylene oxide)-silica nanocomposites

    NASA Astrophysics Data System (ADS)

    Golitsyn, Yury; Schneider, Gerald J.; Saalwächter, Kay

    2017-05-01

    A series of poly(ethylene oxide) nanocomposites with spherical silica was studied by proton NMR spectroscopy, identifying and characterizing reduced-mobility components arising from either room-temperature lateral adsorption or possibly end-group mediated high-temperature bonding to the silica surface. The study complements earlier neutron-scattering results for some of the samples. The estimated thickness of a layer characterized by significant internal mobility resembling backbone rotation ranges from 2 nm for longer (20 k) chains adsorbed on 42 nm diameter particles to 0.5 nm and below for shorter (2 k) chains on 13 nm particles. In the latter case, even lower adsorbed amounts are found when hydroxy endgroups are replaced by methyl endgroups. Both heating and water addition do not lead to significant changes of the observables, in contrast to other systems such as acrylate polymers adsorbed to silica, where temperature- and solvent-induced softening associated with a glass transition temperature gradient was evidenced. We highlight the actual agreement and complementarity of NMR and neutron scattering results, with the earlier ambiguities mainly arising from different sensitivities to the component fractions and the details of their mobility.

  5. Complex dynamics of capillary imbibition of poly(ethylene oxide) melts in nanoporous alumina

    NASA Astrophysics Data System (ADS)

    Yao, Yang; Alexandris, Stelios; Henrich, Franziska; Auernhammer, Günter; Steinhart, Martin; Butt, Hans-Jürgen; Floudas, George

    2017-05-01

    Capillary penetration of a series of entangled poly(ethylene oxide) melts within nanopores of self-ordered alumina follows an approximate t1/2 behavior according to the Lucas-Washburn equation; t is the time. However, the dependence on the capillary diameter deviates from the predicted proportionality to d1/2; d is the pore diameter. We observed a reversal in the dynamics of capillary rise with polymer molecular weight. Chains with 50 entanglements (Mw ≤ 100 kg/mol) or less show a slower capillary rise than theoretically predicted as opposed to chains with more entanglements (Mw ≥ 500 kg/mol) that display a faster capillary rise. Although a faster capillary rise has been predicted by theory and observed experimentally, it is the first time to our knowledge that a slower capillary rise is observed for an entangled polymer melt under conditions of strong confinement (with 2Rg/d = 1). These results are discussed in the light of theoretical predictions for the existence of a critical length scale that depends on the molecular weight and separates the microscopic (d < d*) from the macroscopic (d > d*) regime.

  6. 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.

  7. Integrating nitric oxide into salicylic acid and jasmonic acid/ ethylene plant defense pathways

    PubMed Central

    Mur, Luis A. J.; Prats, Elena; Pierre, Sandra; Hall, Michael A.; Hebelstrup, Kim H.

    2013-01-01

    Plant defense against pests and pathogens is known to be conferred by either salicylic acid (SA) or jasmonic acid (JA)/ethylene (ET) pathways, depending on infection or herbivore-grazing strategy. It is well attested that SA and JA/ET pathways are mutually antagonistic allowing defense responses to be tailored to particular biotic stresses. Nitric oxide (NO) has emerged as a major signal influencing resistance mediated by both signaling pathways but no attempt has been made to integrate NO into established SA/JA/ET interactions. NO has been shown to act as an inducer or suppressor of signaling along each pathway. NO will initiate SA biosynthesis and nitrosylate key cysteines on TGA-class transcription factors to aid in the initiation of SA-dependent gene expression. Against this, S-nitrosylation of NONEXPRESSOR OF PATHOGENESIS-RELATED PROTEINS1 (NPR1) will promote the NPR1 oligomerization within the cytoplasm to reduce TGA activation. In JA biosynthesis, NO will initiate the expression of JA biosynthetic enzymes, presumably to over-come any antagonistic effects of SA on JA-mediated transcription. NO will also initiate the expression of ET biosynthetic genes but a suppressive role is also observed in the S-nitrosylation and inhibition of S-adenosylmethionine transferases which provides methyl groups for ET production. Based on these data a model for NO action is proposed but we have also highlighted the need to understand when and how inductive and suppressive steps are used. PMID:23818890

  8. Nuclear magnetic relaxation study of poly(ethylene oxide)-lithium salt based electrolytes

    NASA Astrophysics Data System (ADS)

    Donoso, J. P.; Bonagamba, T. J.; Panepucci, H. C.; Oliveira, L. N.; Gorecki, W.; Berthier, C.; Armand, M.

    1993-06-01

    We have studied the low-temperature NMR line shape for three nuclei (1H, 7Li, and 19F) in poly(ethylene oxide)-lithium salts (LiClO4, LiBF4, and LiAsF6) solid polymer ionic conductors and measured their spin-lattice relaxation rates as functions of frequency and temperature. The three nuclei probe the dynamics of the polymer segments, the cations, and the anions. We find that the Li+ cations follow the segmental motion of the chain, while the anions move independently. Homonuclear interactions and heteronuclear interactions with the polymer and the anion contribute to the 7Li line shape. When the heteronuclear contributions were selectively eliminated by the decoupling method, it was found that the Li-H interaction accounts for 80%-90% of the linewidth. Additional evidence for the correlation between the cationic and the polymeric motions is provided by the remarkably similar temperature dependences of the measured relaxation rates for 7Li and 1H, which differ significantly from the dependence for 19F. The frequency dependence of the relaxation rates is poorly described by the Bloembergen, Purcell, and Pound model; a recently developed graphical procedure nevertheless shows that the motion of the protons and the anions is governed by a single time scale, while the 7Li ions are affected by an additional scale, associated with the coupling of its quadrupolar moment to the electric-field gradient.

  9. 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.

  10. 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. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Cross-linking of chitosan and chitosan/poly(ethylene oxide) beads: a theoretical treatment.

    PubMed

    Martinez, Leticia; Agnely, Florence; Leclerc, Bernard; Siepmann, Juergen; Cotte, Marine; Geiger, Sandrine; Couarraze, Guy

    2007-09-01

    The major aim of this study was to get deeper insight into the process of polymer cross-linking and the resulting structure of beads based on chitosan (CS) or chitosan/poly(ethylene oxide) (CS/PEO) semi-interpenetrating networks (semi-IPNs) as new carrier materials for oral drug delivery. Spherical hydrogels were prepared by a dropping method. The uptake kinetics of the cross-linking agent glyoxal into the beads were monitored and quantitatively described using Fick's second law of diffusion. High-resolution synchrotron infrared microspectroscopy (SIRM) was used to characterize the inner structures of the beads. Importantly, the diffusion of glyoxal through the hydrogels was found to be much slower than the cross-linking reaction and the mesh size of the created networks to be much larger than the hydrodynamic diameter of glyoxal. The presence of PEO chains slightly decreased the diffusivity of glyoxal due to obstruction effects. However, the cross-linking reaction was not affected. Interestingly, the polymers were homogeneously cross-linked throughout the beads, except for a thin outer shell showing an elevated cross-linking density. Thus, the obtained cross-linked hydrogel-based beads exhibit well-defined polymeric structures and offer an interesting potential as novel oral drug delivery systems.

  12. 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.

  13. Emission characteristics of plastic syringes sterilized with ethylene oxide--a controlled study.

    PubMed

    Chien, Yeh-Chung; Su, Po-Chi; Lee, Lien-Hsiung; Chen, Chang-Yuh

    2009-11-01

    This study examined the emission characteristics of ethylene oxide (EO)-sterilized syringes under various environmental conditions, aiming to develop control strategies to minimize worker exposure. Experiments were performed in a facility in which temperature, relative humidity (RH), and air change rate (ACR) were controlled. Analytical results indicate that the main effects of the four test variables on kinetic parameters were statistically significant (p < 0.05), except for the effect of the product on the decay rate constant, the effect of ACR on maximum EO concentration, and effect of RH on the area under the curve-days 1 and 2. The interactive effects among test variables were also evident, indicating complex emission behaviors. The mean EO emission factors during the days 1 and 2 and at the 48th hour for the 1- and 30-ml products were 2302, 1301, and 1031 mg/m(3)/h, and 871, 490, and 381 mg/m(3)/h, respectively. The times required for air EO concentrations from tested products to return to approximately 0 and 1 ppm (permissible limit) were 417 and 218 h, respectively. Plastic content, temperature, RH, and ACR affected EO emissions. ACR is an achievable means of control; however, the aeration area/system should be isolated to ensure adequate ventilation is achieved.

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

    PubMed

    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(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.

  15. Flocculation with poly(ethylene oxide)/tyrosine-rich polypeptide complexes.

    PubMed

    Lu, Chen; Pelton, Robert

    2005-04-26

    New insights into the mechanism for the flocculation of aqueous colloids by the sequential addition of a water-borne phenolic polymer, called cofactor, followed by very high molecular poly(ethylene oxide) (PEO) are presented. It is proposed that PEO/cofactor complexes form in the aqueous phase and adsorb onto the surfaces of the target colloidal particles. Flocculation will occur if PEO/cofactor complex on one particle will bind to adsorbed complex on a second particle; i.e., if the complexes are sticky. The proposed mechanism was illustrated by flocculation experiments with precipitated calcium carbonate, very high molecular weight PEO, and a polypeptide cofactor called PEY1 which was a 1:1 random copolymer of l-glycine and l-tyrosine. Independent measurements of the PEO/PEY1 complex properties, in the absence of calcium carbonate, were used to support the mechanism. In order for PEO/PEY1 complexes to be sticky, they must simultaneously have unbound PEY1 and polymer segments. With time the complexes deactivate (i.e., lose their stickiness) by a reconfiguration process which results in elimination of either unbound PEY1 or PEO segments.

  16. Influence of chain topology on polymer crystallization: poly(ethylene oxide) (PEO) rings vs. linear chains.

    PubMed

    Zardalidis, George; Mars, Julian; Allgaier, Jürgen; Mezger, Markus; Richter, Dieter; Floudas, George

    2016-10-04

    The absence of entanglements, the more compact structure and the faster diffusion in melts of cyclic poly(ethylene oxide) (PEO) chains have consequences on their crystallization behavior at the lamellar and spherulitic length scales. Rings with molecular weight below the entanglement molecular weight (M < Me), attain the equilibrium configuration composed from twice-folded chains with a lamellar periodicity that is half of the corresponding linear chains. Rings with M > Me undergo distinct step-like conformational changes to a crystalline lamellar with the equilibrium configuration. Rings melt from this configuration in the absence of crystal thickening in sharp contrast to linear chains. In general, rings more easily attain their extended equilibrium configuration due to strained segments and the absence of entanglements. In addition, rings have a higher equilibrium melting temperature. At the level of the spherulitic superstructure, growth rates are much faster for rings reflecting the faster diffusion and more compact structure. With respect to the segmental dynamics in their semi-crystalline state, ring PEOs with a steepness index of ∼34 form some of the "strongest" glasses.

  17. Ethylene diamine-assisted synthesis of iron oxide nanoparticles in high-boiling polyolys.

    PubMed

    Arndt, Darius; Zielasek, Volkmar; Dreher, Wolfgang; Bäumer, Marcus

    2014-03-01

    The decomposition of iron(III) acetylacetonate in high-boiling polyols such as diethylene glycole is an efficient way to produce water-soluble iron oxide nanoparticles (IONPs) with small sizes. We present an extension of this method by introducing ethylene diamine (EDA) or diethylene triamine (DTA) as a structure-directing agent and adding polyvinylpyrrolidone (PVP) as a stabilizing agent. The synthesis was studied with respect to effects of the chain length of the polyol used as solvent, the chain length of the structure-directing agent, the presence of PVP, the heating rate, and the nature of the precursor. By varying these parameters, we were able to show, that probably an interplay of the structure-directing agent and the polyol plays an important role for the stabilization and growth of the different facets of the IONP crystal. The chain length of the polyol used as solvent alters the influence of EDA or DTA as stabilizer of {111} facets, leading to IONPs with spherical, tetrahedral, or nanoplate morphology and mean diameters ranging from 4 nm up to 25 nm. PVP in the reaction medium narrows down particle size and shape distributions and promotes the formation of very stable, water-based colloidal solutions. The saturation magnetization of the particles was determined by a superconducting quantum interference device (SQUID) and their ability to act as a T2-contrast agent was tested by magnetic resonance imaging (MRI). Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Scaling law of poly(ethylene oxide) chain permeation through a nanoporous wall.

    PubMed

    Choudhury, Rudra Prosad; Galvosas, Petrik; Schönhoff, Monika

    2008-10-23

    This paper presents a study of the permeation of poly(ethylene oxide) (PEO) chains through the nanoporous wall of hollow polymeric capsules prepared by self-assembly of polyelectrolytes. We employ the method of pulsed field gradient (PFG) NMR diffusion to distinguish chains in different sites, i.e., in the capsule interior and free chains in the dispersion, by their respective diffusion coefficient. From a variation of the observation time, the time scale of the molecular exchange between both sites and thus the permeation rate constant is extracted from a two-site exchange model. Permeation rate constants show two different regimes with a different dependence on chain length. This suggests a transition between two different mechanisms of permeation as the molecular weight is increased. In either regime, the permeation time can be described by a scaling law tau approximately N (b) , with b = (4)/ 3 for short chains and b = (1)/ 3 for long chains. We discuss these exponents, which clearly differ from the theoretical predictions for chain translocation.

  19. The diffusion and conduction of lithium in poly(ethylene oxide)-based sulfonate ionomers

    NASA Astrophysics Data System (ADS)

    LaFemina, Nikki H.; Chen, Quan; Colby, Ralph H.; Mueller, Karl T.

    2016-09-01

    Pulsed field gradient nuclear magnetic resonance spectroscopy and dielectric relaxation spectroscopy have been utilized to investigate lithium dynamics within poly(ethylene oxide) (PEO)-based lithium sulfonate ionomers of varying ion content. The ion content is set by the fraction of sulfonated phthalates and the molecular weight of the PEO spacer, both of which can be varied independently. The molecular level dynamics of the ionomers are dominated by either Vogel-Fulcher-Tammann or Arrhenius behavior depending on ion content, spacer length, temperature, and degree of ionic aggregation. In these ionomers the main determinants of the self-diffusion of lithium and the observed conductivities are the ion content and ionic states of the lithium ion, which are profoundly affected by the interactions of the lithium ions with the ether oxygens of the polymer. Since many lithium ions move by segmental polymer motion in the ion pair state, their diffusion is significantly larger than that estimated from conductivity using the Nernst-Einstein equation.

  20. Structure and phase behavior of the poly(ethylene oxide)-thiourea complex prepared by electrospinning.

    PubMed

    Liu, Yang; Antaya, Hélène; Pellerin, Christian

    2010-02-25

    Electrospinning was used for the first time to prepare nanofibers of the host/guest complex between poly(ethylene oxide) (PEO) and thiourea. It is shown by differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) that the stoichiometry of the complex is (EO)(12)-(thiourea)(8), settling a series of conflicting values in literature reports. The complex crystallizes in a monoclinic unit cell with a = 9.15 A, b = 18.88 A, c = 8.25 A, and beta = 92.35 degrees. On the basis of WAXD, infrared spectroscopy, and polarized Raman scattering measurements, it is proposed that the complex adopts a layered structure in which alternating PEO and thiourea layers are stabilized by intermolecular hydrogen bonds. This structure is highly reminiscent of that of the beta complex between PEO and urea. A phase diagram was determined and shows that the complex melts incongruently at 110 degrees C to form a peritectic liquid and crystals of pure thiourea. The nanofibers of the PEO-thiourea present a very large molecular orientation with a (c) value of 0.76, among the largest reported for electrospun materials.

  1. Surface dilational moduli of poly (ethylene oxide), poly (methyl methacrylate), and their blend films.

    PubMed

    Kato, Satoaki; Kawaguchi, Masami

    2012-10-15

    Surface dilational moduli of poly (ethylene oxide) (PEO), poly (methyl methacrylate) (PMMA), and compatible PEO/PMMA blend films spread at the air-water interface were investigated as a function of surface concentration. The surface dilational modulus of an expanded PEO film increased as the surface concentration increased to 0.4 mg/m(2), which corresponds to the limiting surface area of PEO. After peaking at this value, the surface dilational modulus decreased with an increase in the PEO concentration. Lissajous orbits of PEO films exhibited positive hysteresis loops for all surface concentration ranges. On the other hand, the surface dilational modulus of a condensed PMMA film steeply increased as the surface concentration increased. Lissajous orbits of PMMA films changed from positive hysteresis loops to negative loops at the surface concentration at which the surface pressure reached in the plateau region. The magnitude of the surface dilational modulus of PMMA was larger than that of PEO at a fixed surface concentration. The surface dilational moduli of the PEO/PMMA blend films increased with the total surface concentration and their magnitudes were less than those of the individual PMMA films and larger than those of the individual PEO films at fixed surface concentrations. Lissajous orbits of the PEO/PMMA blend films also changed from positive hysteresis loops to negative loops beyond the surface concentration at which the plateau surface pressure of PEO was attained.

  2. Exposure to ethylene oxide in hospitals: biological monitoring and influence of glutathione S-transferase and epoxide hydrolase polymorphisms.

    PubMed

    Haufroid, Vincent; Merz, Brigitte; Hofmann, Annette; Tschopp, Alois; Lison, Dominique; Hotz, Philippe

    2007-04-01

    Ethylene oxide is considered as a human carcinogen. A biomarker of exposure would be a useful instrument to assess the risk in occupationally exposed workers. This cross-sectional study aimed at examining (a) whether the urinary excretion of a metabolite of ethylene oxide, 2-hydroxyethyl mercapturic acid (HEMA), could be used for monitoring occupational exposure and (b) whether glutathione S-transferase (GST) and epoxide hydrolase genotypes influenced biological monitoring. Exposure to ethylene oxide was measured by personal sampling in 80 hospital workers (95% of those eligible). HEMA concentrations were determined in three urine samples (baseline, end of shift, and next morning) by liquid chromatography with tandem mass spectrometry. GSTs (GSTT1, GSTM1, and GSTP1) and epoxide hydrolase (EPHX1) were also genotyped. The influence of exposure, genotypes, and several other factors was examined in multiple regression analyses. Exposure was always <1 parts per million. On a group basis, exposure and a non-null GSTT1 genotype increased the HEMA concentrations in the urine sample collected at the end of the shift and these factors remained statistically significant after considering possible confounding or modifying factors.

  3. Application of the aqueous two-phase systems of ethylene and propylene oxide copolymer-maltodextrin for protein purification.

    PubMed

    Bolognese, Belén; Nerli, Bibiana; Picó, Guillermo

    2005-01-25

    In this study, the effect of several factors that govern the partitioning behaviour of three model proteins, such as bovine serum albumin, lysozyme and trypsin was analysed in a two-phase system formed by maltodextrin and a copolymer of ethylene and propylene oxides. The protein partition coefficient (K(r)) showed to be very sensitive to temperature changes, protein molecular weight, pH medium and the lyotropic ion presence. The phase diagram obtained for these novel polymer-polymer two-phase systems shows two phases with high polymer concentrations. The maltodextrin is enriched in the bottom phase while the copolymer of ethylene and propylene oxides is found in the upper phase. Since this copolymer is thermoreactive, the upper phase can be removed and heated above the copolymer's cloud point resulting in the formation of a new two-phase system with a lower water phase, containing the target protein and an upper copolymer-rich phase. Our results show that systems formed by maltodextrin and a copolymer of ethylene and propylene oxides may be considered as an interesting alternative to be used in protein purification due to their low cost, and also because they offer a viable solution to problems of polymer removal and recycling.

  4. Crystal structure of an ethylene sorption complex of fully vacuum-dehydrated fully Ag+-exchanged zeolite X (FAU). Silver atoms have reduced ethylene to give CH2 2- carbanions at framework oxide vacancies.

    PubMed

    Lee, Young Mi; Choi, Seo Jung; Kim, Yang; Seff, Karl

    2005-11-03

    The crystal structure of an ethylene sorption complex of fully vacuum-dehydrated fully Ag(+)-exchanged zeolite X (FAU), a = 24.865(2) A, has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd at 21 degrees C. It is very different from the ethylene complex of Ag(92)-X that had been dehydrated at 400 degrees C in flowing oxygen, as were the two dehydrated structures. The crystal was prepared by ion exchange in a flowing stream of aqueous 0.05 M AgNO(3) for 3 days, followed by dehydration at 400 degrees C and 2 x 10(-6) Torr for 2 days, followed by exposure to 300 Torr of zeolitically dry ethylene gas for 2 h at 21 degrees C. The structure was determined in this atmosphere and was refined using all data to the final error indices (based upon the 534 reflections for which F(o) > 4sigma(F(o))) R(1) = 0.062 and wR(2) = 0.135. In this structure, per unit cell, 14 Ag(+) ions were found at the octahedral site I (Ag-O = 2.611(9) A), and 32 partially reduced Ag(+) ions fill two different site I' positions deep in the sodalite cavities (Ag-O = 2.601(13) and 2.618(12) A). The sodalite cavities host two different cationic silver clusters. In about 47% of sodalite units, eight silver atoms form interpenetrating tetrahedra, Ag(8)(n+) (n = 4 is suggested), with T(d)() symmetry. The other 53% of the sodalite units host cyclo-Ag(4)(m+) (m = 2 is suggested) cations with near S(4) symmetry. These clusters are very similar to those in vacuum-dehydrated Ag(92)-X. Thirty-two Ag(+) ions fill the single 6-rings, 15 at site II' (Ag-O = 2.492(10) A), and 17 at site II (Ag-O = 2.460(9) A). The latter 17 lie in supercages where each forms a lateral pi-complex with an ethylene molecule. In turn, each C(2)H(4) molecule forms two cis electrostatic hydrogen bonds to framework oxygens. The remaining 14 Ag+ ions occupy three different II' sites. Vacuum dehydration had caused substantial decomposition: per unit cell, 30 of the 92 Ag(+) ions were reduced and 15

  5. Development and validation of a protocol for field validation of passive dosimeters for ethylene oxide excursion limit monitoring

    SciTech Connect

    Puskar, M.A.; Szopinski, F.G.; Hecker, L.H. )

    1991-04-01

    An exposure and analysis protocol is described for the field validation of passive dosimeters for ethylene oxide (EtO) excursion limit monitoring. The protocol calls for the use of a field exposure chamber with concurrent sampling using Tedlar air-sampling bags. The bags are analyzed immediately after sampling by gas chromatography with flame ionization detection (GC-FID). The chamber design allows all monitors to be exposed for the exact same time in the field. The sampling and analysis procedure not only determines the actual concentration of EtO present during the monitor's exposure but estimates if concentrations of EtO vary from point to point in the monitor array during the exposure. In chamber operation, the accuracy of the standard generator used to calibrate the GC-FID was independently verified in the field by the standard additions method. The sampling bias of the sampling train was determined to be -3.5% in the 2.4 ppm to 14.3 ppm concentration range. To estimate the stability of collected EtO samples in Tedlar bags, the rate of EtO loss in the bags was determined to be 0.011 ppm/hr at 2.57 ppm and 0.066 ppm/hr at 8.07 ppm. Sampling bias of the passive methods by additional EtO exposure of the monitors in the closed chamber after sampling and during purging was determined to be +1.5%. The Tedlar bag sampling method with subsequent GC-FID determination demonstrated a coefficient of variation of 1.8% at 2.43 ppm.

  6. Ethylene oxide allergy in patients on hemodialysis waiting for kidney transplantation: logistical nightmare or challenge? A case report.

    PubMed

    Monbaliu, D; Van Breussegem, A; Onsia, A; Vandermeersch, E; Segers, C; Meert, W; Kochuyt, A-M; Pirenne, J; Claes, K

    2010-12-01

    Ethylene oxide (EO) is widely used as a sterilization gas for heat-sensitive devices. In EO-sensitized patients, this type of sterilization can cause rare but major allergic reactions such as hives, rash, asthma, or anaphylactic shock. Hemodialysis patients in particular are at risk of developing hypersensitivity to EO. In these patients, surgical interventions should be planned far in advance allowing a thorough EO-free preparation of all equipment needed for the surgery as well as for the pre-, peri-, and postoperative care. In contrast to elective surgery, kidney transplantation with allografts from deceased donors cannot be planned; exact timing is unpredictable. Furthermore, transplantation may take place years after patients have been put on the waiting list. Listing of patients sensitive for EO is therefore a logistical and medical challenge for all health care professionals involved in the patient's care (eg, surgeons, nephrologists, anesthetists, nurses, pharmacists, and sterilization specialists). This case report describes a patient with chronic kidney disease stage V who developed EO allergy during hemodialysis while waiting for a kidney transplantation. Diagnosis was made based on clinical signs and confirmed biochemically (including a positive radioallergosorbent test). Because the only treatment is avoidance of contact with EO-sterilized materials, a strict EO-free protocol was developed to allow an uneventful transplantation thereafter. Subsequently, 4 newly diagnosed EO-sensitive patients on the active kidney transplantation waiting list were diagnosed, and 1 of these patients has been transplanted successfully. EO allergy in patients on the waiting list for kidney transplantation is a unique challenging situation which, to the best of our knowledge, has not been reported yet for kidney transplantation. This report further highlights the logistical preparation of a renal transplantation, including anesthesiologic, surgical, and postoperative care

  7. The ALMA-PILS survey: First detections of ethylene oxide, acetone and propanal toward the low-mass protostar IRAS 16293-2422

    NASA Astrophysics Data System (ADS)

    Lykke, J. M.; Coutens, A.; Jørgensen, J. K.; van der Wiel, M. H. D.; Garrod, R. T.; Müller, H. S. P.; Bjerkeli, P.; Bourke, T. L.; Calcutt, H.; Drozdovskaya, M. N.; Favre, C.; Fayolle, E. C.; Jacobsen, S. K.; Öberg, K. I.; Persson, M. V.; van Dishoeck, E. F.; Wampfler, S. F.

    2017-01-01

    Context. One of the open questions in astrochemistry is how complex organic and prebiotic molecules are formed. The unsurpassed sensitivity of the Atacama Large Millimeter/submillimeter Array (ALMA) takes the quest for discovering molecules in the warm and dense gas surrounding young stars to the next level. Aims: Our aim is to start the process of compiling an inventory of oxygen-bearing complex organic molecules toward the solar-type Class 0 protostellar binary IRAS 16293-2422 from an unbiased spectral survey with ALMA, Protostellar Interferometric Line Survey (PILS). Here we focus on the new detections of ethylene oxide (c-C2H4O), acetone (CH3COCH3), and propanal (C2H5CHO). Methods: With ALMA, we surveyed the spectral range from 329 to 363 GHz at 0.5″ (60 AU diameter) resolution. Using a simple model for the molecular emission in local thermodynamical equilibrium, the excitation temperatures and column densities of each species were constrained. Results: We successfully detect propanal (44 lines), ethylene oxide (20 lines) and acetone (186 lines) toward one component of the protostellar binary, IRAS 16293B. The high resolution maps demonstrate that the emission for all investigated species originates from the compact central region close to the protostar. This, along with a derived common excitation temperature of Tex ≈ 125 K, is consistent with a coexistence of these molecules in the same gas. Conclusions: The observations mark the first detections of acetone, propanal and ethylene oxide toward a low-mass protostar. The relative abundance ratios of the two sets of isomers, a CH3COCH3/C2H5CHO ratio of 8 and a CH3CHO/c-C2H4O ratio of 12, are comparable to previous observations toward high-mass protostars. The majority of observed abundance ratios from these results as well as those measured toward high-mass protostars are up to an order of magnitude above the predictions from chemical models. This may reflect either missing reactions or uncertain rates in the

  8. ANALYSIS OF DISSOLVED METHANE, ETHANE, AND ETHYLENE IN GROUND WATER BY A STANDARD GAS CHROMATOGRAPHIC TECHNIQUE

    EPA Science Inventory

    The measurement of dissolved gases such as methane, ethane, and ethylene in ground water is important in determining whether intrinsic bioremediation is occurring in a fuel- or solvent-contaminated aquifer. A simple procedure is described for the collection and subsequent analys...

  9. ANALYSIS OF DISSOLVED METHANE, ETHANE, AND ETHYLENE IN GROUND WATER BY A STANDARD GAS CHROMATOGRAPHIC TECHNIQUE

    EPA Science Inventory

    The measurement of dissolved gases such as methane, ethane, and ethylene in ground water is important in determining whether intrinsic bioremediation is occurring in a fuel- or solvent-contaminated aquifer. A simple procedure is described for the collection and subsequent analys...

  10. Inspecting an ethylene pipe line

    SciTech Connect

    Ramsvig, D.M. ); Duncan, J.; Zillinger, L. )

    1991-07-01

    This paper reports on the Alberta Gas Ethylene Co. (AGEC), completion of intensive internal cleaning and inspection program on their 112-mi ethylene pipe line. AGEC operates two ethylene manufacturing facilities in central Alberta, Canada. The ethylene plants are located 12.4 mi east of Red Deer, Alta., at Joffre, and supply two customers in Joffre. The remaining ethylene is shipped by the 112-mi, 12-in. line to a storage cavern near Edmonton.

  11. A novel reductive graphene oxide-based magnetic molecularly imprinted poly(ethylene-co-vinyl alcohol) polymers for the enrichment and determination of polychlorinated biphenyls in fish samples.

    PubMed

    Lin, Saichai; Gan, Ning; Zhang, Jiabin; Chen, Xidong; Cao, Yuting; Li, Tianhua

    2015-06-01

    The novel reductive graphene oxide-based magnetic molecularly imprinted poly(ethylene-co-vinyl alcohol) polymers (rGO@m-MIPs) were successfully synthesized as adsorbents for six kinds of polychlorinated biphenyls (PCBs) in fish samples. rGO@m-MIPs was prepared by surface molecular imprinting technique. Besides, Fe3 O4 nanoparticles (NPs) were employed as magnetic supporters, and rGO@Fe3 O4 was in situ synthesis. Different from functional monomer and cross-linker in traditional molecularly imprinted polymer, here, 3,4-dichlorobenzidine was employed as dummy molecular and poly(ethylene-co-vinyl alcohol) was adopted as the imprinted polymers. After morphology and inner structure of the magnetic adsorbent were characterized, the adsorbent was employed for disperse solid phase extraction toward PCBs and exhibited great selectivity and high adsorption efficiency. This material was verified by determination of PCBs in fish samples combined with gas chromatography-mass spectrometry (GC-MS) method. According to the detection, the low detection limits (LODs) of PCBs were 0.0035-0.0070 µg l(-1) and spiked recoveries ranged between 79.90 and 94.23%. The prepared adsorbent can be renewable for at least 16 times and expected to be a new material for the enrichment and determination of PCBs from contaminated fish samples.

  12. 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).

  13. Process for selected gas oxide removal by radiofrequency catalysts

    DOEpatents

    Cha, C.Y.

    1993-09-21

    This process to remove gas oxides from flue gas utilizes adsorption on a char bed subsequently followed by radiofrequency catalysis enhancing such removal through selected reactions. Common gas oxides include SO[sub 2] and NO[sub x]. 1 figure.

  14. Rapid analysis of dissolved methane, ethylene, acetylene and ethane using partition coefficients and headspace-gas chromatography.

    PubMed

    Lomond, Jasmine S; Tong, Anthony Z

    2011-01-01

    Analysis of dissolved methane, ethylene, acetylene, and ethane in water is crucial in evaluating anaerobic activity and investigating the sources of hydrocarbon contamination in aquatic environments. A rapid chromatographic method based on phase equilibrium between water and its headspace is developed for these analytes. The new method requires minimal sample preparation and no special apparatus except those associated with gas chromatography. Instead of Henry's Law used in similar previous studies, partition coefficients are used for the first time to calculate concentrations of dissolved hydrocarbon gases, which considerably simplifies the calculation involved. Partition coefficients are determined to be 128, 27.9, 1.28, and 96.3 at 30°C for methane, ethylene, acetylene, and ethane, respectively. It was discovered that the volume ratio of gas-to-liquid phase is critical to the accuracy of the measurements. The method performance can be readily improved by reducing the volume ratio of the two phases. Method validation shows less than 6% variation in accuracy and precision except at low levels of methane where interferences occur in ambient air. Method detection limits are determined to be in the low ng/L range for all analytes. The performance of the method is further tested using environmental samples collected from various sites in Nova Scotia.

  15. 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.

  16. Group VII Ethylene Response Factors Coordinate Oxygen and Nitric Oxide Signal Transduction and Stress Responses in Plants1

    PubMed Central

    Gibbs, Daniel J.; Conde, Jorge Vicente; Berckhan, Sophie; Prasad, Geeta; Mendiondo, Guillermina M.; Holdsworth, Michael J.

    2015-01-01

    The group VII ethylene response factors (ERFVIIs) are plant-specific transcription factors that have emerged as important regulators of abiotic and biotic stress responses, in particular, low-oxygen stress. A defining feature of ERFVIIs is their conserved N-terminal domain, which renders them oxygen- and nitric oxide (NO)-dependent substrates of the N-end rule pathway of targeted proteolysis. In the presence of these gases, ERFVIIs are destabilized, whereas an absence of either permits their accumulation; ERFVIIs therefore coordinate plant homeostatic responses to oxygen availability and control a wide range of NO-mediated processes. ERFVIIs have a variety of context-specific protein and gene interaction partners, and also modulate gibberellin and abscisic acid signaling to regulate diverse developmental processes and stress responses. This update discusses recent advances in our understanding of ERFVII regulation and function, highlighting their role as central regulators of gaseous signal transduction at the interface of ethylene, oxygen, and NO signaling. PMID:25944828

  17. The application of mass spectrometry in molecular dosimetry: ethylene oxide as an example.

    PubMed

    Wu, Kuen-Yuh; Chiang, Su-Yin; Shih, Wei-Chung; Huang, Chih-Chun Jean; Chen, Ming-Feng; Swenberg, James A

    2011-01-01

    Mass spectrometry plays an increasingly important role in the search for and quantification of novel chemically specific biomarkers. The revolutionary advances in mass spectrometry instrumentation and technology empower scientists to specifically analyze DNA and protein adducts, considered as molecular dosimeters, derived from reactions of a carcinogen or its active metabolites with DNA or protein. Analysis of the adducted DNA bases and proteins can elucidate the chemically reactive species of carcinogens in humans and can serve as risk-associated biomarkers for early prediction of cancer risk. In this article, we review and compare the specificity, sensitivity, resolution, and ease-of-use of mass spectrometry methods developed to analyze ethylene oxide (EO)-induced DNA and protein adducts, particularly N7-(2-hydroxyethyl)guanine (N7-HEG) and N-(2-hydroxyethyl)valine (HEV), in human samples and in animal tissues. GC/ECNCI-MS analysis after HPLC cleanup is the most sensitive method for quantification of N7-HEG, but limited by the tedious sample preparation procedures. Excellent sensitivity and specificity in analysis of N7-HEG can be achieved by LC/MS/MS analysis if the mobile phase, the inlet (split or splitless), and the collision energy are properly optimized. GC/ECNCI-HRMS and GC/ECNCI-MS/MS analysis of HEV achieves the best performance as compared with GC/ECNCI-MS and GC/EI-MS. In conclusion, future improvements in high-throughput capabilities, detection sensitivity, and resolution of mass spectrometry will attract more scientists to identify and/or quantify novel molecular dosimeters or profiles of these biomarkers in toxicological and/or epidemiological studies. Copyright © 2011 Wiley Periodicals, Inc.

  18. Ethylene oxide sterilization in the medical-supply manufacturing industry: assessment and control of worker exposure.

    PubMed

    Chien, Yeh-Chung; Liu, Hung-Hsin; Lin, Yi-Chang; Su, Po-Chi; Li, Lien-Hsiung; Chang, Cheng-Ping; Tang, Da-Toung; Chen, Chang-Yuh

    2007-11-01

    In 2005, the Taiwan Institute of Occupational Safety and Health started an on-site consulting program for the medical supplies manufacturing industry, which use ethylene oxide (EO) as a sterilant, with the goal of enhancing occupational hygiene practices and controlling EO-related risks. This study presents EO exposure assessment results and examines the effectiveness of control measures. Detailed surveys, including exposure monitoring, were conducted at 10 factories. Airborne EO was collected using an HBr-coated charcoal tube and analyzed using GC/MS. Sterilizer operators had an average short-term EO exposure level of 27.61 ppm during unloading; mean time-weighted average workshift exposure was 7.35 ppm. High EO concentrations were also present throughout the facilities. Specifically, mean EO concentrations in the aeration area, near the sterilizer and in the warehouse were 10.19, 5.75, and 8.78 ppm, respectively. These findings indicate that immediate controls are needed, and that EO emissions from sterilized products during storage cannot be overlooked. Worker short-term exposures during unloading was inversely correlated (p < 0.05) with the numbers of poststerilization purge cycle applied. The specific controls implemented and their usefulness is discussed. Increasing the number of poststerilization purge cycles is a simple approach to eliminating extremely high exposure during unloading. Improvements to ventilation, particularly in the aeration area and warehouse, were also effective in minimizing worker exposures. Use of effective respirator is recommended until the EO exposure levels, averaging 3.41 ppm after the controls, fall below the permissible exposure limit.

  19. Sustained release from hot-melt extruded matrices based on ethylene vinyl acetate and polyethylene oxide.

    PubMed

    Almeida, A; Brabant, L; Siepmann, F; De Beer, T; Bouquet, W; Van Hoorebeke, L; Siepmann, J; Remon, J P; Vervaet, C

    2012-11-01

    The aim of the present study was to evaluate the importance of matrix flexibility of hot-melt extruded (HME) ethylene vinyl acetate (EVA) matrices (with vinyl acetate (VA) contents of 9%, 15%, 28% and 40%), through the addition of hydrophilic polymers with distinct swelling capacity. Polyethylene oxide (PEO 100K, 1M and 7M) was used as swelling agent and metoprolol tartrate (MPT) as model drug. The processability via HME and drug release profiles of EVA/MPT/PEO formulations were assessed. Solid state characteristics, porosity and polymer miscibility of EVA/PEO matrices were evaluated by means of DSC, X-ray tomography and Raman spectroscopy. The processability via HME varied according to the VA content: EVA 40 and 28 were extruded at 90°C, whereas higher viscosity EVA grades (EVA 15 and 9) required a minimum extrusion temperature of 110°C to obtain high-quality extrudates. Drug release from EVA matrices depended on the VA content, PEO molecular weight and PEO content, matrix porosity as well as pore size distribution. Interestingly, the interplay of PEO leaching, matrix swelling, water influx and changes in matrix porosity influenced drug release: EVA 40- and 28-based matrices extruded with PEO of higher MW accelerated drug release, whereas for EVA 15- and 9-based matrices, drug release slowed down. These differences were related to the distinct polymer flexibility imposed by the VA content (lower VA content presents higher crystallinity and less free movement of the amorphous segments resulting in a higher rigidity). In all cases, diffusional mass transport seems to play a major role, as demonstrated by mathematical modeling using an analytical solution of Fick's second law. The bioavailability of EVA 40 and 28 matrices in dogs was not significantly different, independent of PEO 7M concentration.

  20. 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.

  1. Nonfouling poly(ethylene oxide) layers end-tethered to polydopamine.

    PubMed

    Pop-Georgievski, Ognen; Verreault, Dominique; Diesner, Mark-Oliver; Proks, Vladimír; Heissler, Stefan; Rypáček, František; Koelsch, Patrick

    2012-10-09

    Nonfouling surfaces capable of reducing protein adsorption are highly desirable in a wide range of applications. Coating of surfaces with poly(ethylene oxide) (PEO), a water-soluble, nontoxic, and nonimmunogenic polymer, is most frequently used to reduce nonspecific protein adsorption. Here we show how to prepare dense PEO brushes on virtually any substrate by tethering PEO to polydopamine (PDA)-modified surfaces. The chain lengths of hetero-bifunctional PEOs were varied in the range of 45-500 oxyethylene units (M(n) = 2000-20,000). End-tethering of PEO chains was performed through amine and thiol headgroups from reactive polymer melts to minimize excluded volume effects. Surface plasmon resonance (SPR) was applied to investigate the adsorption of model protein solutions and complex biologic medium (human blood plasma) to the densely packed PEO brushes. The level of protein adsorption of human serum albumin and fibrinogen solutions was below the detection limit of the SPR measurements for all PEO chains end-tethered to PDA, thus exceeding the protein resistance of PEO layers tethered directly on gold. It was found that the surface resistance to adsorption of lysozyme and human blood plasma increased with increasing length and brush character of the PEO chains end-tethered to PDA with a similar or better resistance in comparison to PEO layers on gold. Furthermore, the chain density, thickness, swelling, and conformation of PEO layers were determined using spectroscopic ellipsometry (SE), dynamic water contact angle (DCA) measurements, infrared reflection-absorption spectroscopy (IRRAS), and vibrational sum-frequency-generation (VSFG) spectroscopy, the latter in air and water.

  2. 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

  3. Wear reduction in ceramic bearings by surface generated pyrolytic carbon continuously replenished by ethylene gas

    NASA Astrophysics Data System (ADS)

    Lauer, J. L.; Davis, L. C.

    1993-12-01

    Sliding tests with a pin-on-disc tribometer and both sliding and rolling tests with a modified four-ball tester at bulk temperatures of about 500 C and contact pressures of about 2.2 GPa have demonstrated up to 80% reductions of friction and wear with silicon nitride surfaces when a stream of ethylene is directed into the conjunction region. The effects are even more pronounced when the ethylene is prenucleated by a flow over a coil of nichrome wire electrically heated to about 800 C and located about 30 cm upstream of the exit nozzle. Steel and Ni-plated steel are lubricated by this method even more efficiently at lower temperatures.

  4. Wear reduction in ceramic bearings by surface generated pyrolytic carbon continuously replenished by ethylene gas

    NASA Technical Reports Server (NTRS)

    Lauer, J. L.; Davis, L. C.

    1993-01-01

    Sliding tests with a pin-on-disc tribometer and both sliding and rolling tests with a modified four-ball tester at bulk temperatures of about 500 C and contact pressures of about 2.2 GPa have demonstrated up to 80% reductions of friction and wear with silicon nitride surfaces when a stream of ethylene is directed into the conjunction region. The effects are even more pronounced when the ethylene is prenucleated by a flow over a coil of nichrome wire electrically heated to about 800 C and located about 30 cm upstream of the exit nozzle. Steel and Ni-plated steel are lubricated by this method even more efficiently at lower temperatures.

  5. FT-IR spectra of 90 K films of simple, mixed, and double clathrate hydrates of trimethylene oxide, methyl chloride, carbon dioxide, tetrahydrofuran, and ethylene oxide containing decoupled D/sub 2/O

    SciTech Connect

    Fleyfel, F.; Devlin, J.P.

    1988-02-11

    The spectroscopic investigation of clathrate hydrates prepared by using low-temperature thin-film techniques has been extended to several new gases. These gases have included a highly polar gas (trimethylene oxide or TMO) the simple hydrate of which grows readily from a vapor beam at 120 K, a slightly less polar gas (methyl chloride) the simple hydrate of which grows if the vapor beam is incident onto a crystalline clathrate hydrate base at 125 K, and a nonpolar gas (carbon dioxide) which apparently can only be enclathrated as the mixed hydrate by using a highly polar help gas (e.g., ethylene oxide (EtO)). These structure I hydrates as well as the structure II hydrate of tetrahydrofuran have been prepared under conditions of temperature/base-doping such that no mobile protons exist during the deposit. As a result, it has been possible to isolate intact D/sub 2/O molecules in the water network of the crystalline hydrates. The guest-molecule spectra, all obtained at 90 K, show (a) the apparent generality of the rule that guest-molecule stretching-mode frequencies decrease with an increase in cage size and (b) that the effective size of the structure I small cage increases as the size of the molecule occupying the large cage increases.

  6. Poly(ethylene oxide)-modified poly(epsilon-caprolactone) nanoparticles for targeted delivery of tamoxifen in breast cancer.

    PubMed

    Shenoy, Dinesh B; Amiji, Mansoor M

    2005-04-11

    This study was carried out to evaluate and compare the biodistribution profile of tamoxifen when administered intravenously (i.v.) as a simple solution or when encapsulated in polymeric nanoparticulate formulations, with or without surface-stabilizing agents. Tamoxifen-loaded, poly(ethylene oxide)-modified poly(epsilon-caprolactone) (PEO-PCL) nanoparticles were prepared by solvent displacement process that allowed in situ surface modification via physical adsorption of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock polymeric stabilizer (Pluronic). The nanoparticles were characterized for particle size and surface charge. Presence of PEO chains on nanoparticle surface was ascertained by electron spectroscopy for chemical analysis (ESCA). In vivo biodistribution studies were carried out in Nu/Nu athymic mice bearing a human breast carcinoma xenograft, MDA-MB-231 using tritiated [(3)H]-tamoxifen as radio-marker for quantification. PEO-PCL nanoparticles with an average diameter of 150-250 nm, having a smooth spherical shape, and a positive surface charge were obtained with the formulation procedure. About 90% drug encapsulation efficiency was achieved when tamoxifen was loaded at 10% by weight of the polymer. Aqueous wettability, suspendability, and ESCA results showed surface hydrophilization of the PCL nanoparticles by the Pluronics. The primary site of accumulation for the drug-loaded nanoparticles after i.v. administration was the liver, though up to 26% of the total activity could be recovered in tumor at 6h post-injection for PEO-modified nanoparticles. PEO-PCL nanoparticles exhibited significantly increased level of accumulation of the drug within tumor with time as well as extended their presence in the systemic circulation than the controls (unmodified nanoparticles or the solution form). Pluronic surfactants (F-68 and F-108) presented simple means for efficient surface modification and stabilization of PCL nanoparticles

  7. 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.

  8. Gas Generation from Actinide Oxide Materials

    SciTech Connect

    George Bailey; Elizabeth Bluhm; John Lyman; Richard Mason; Mark Paffett; Gary Polansky; G. D. Roberson; Martin Sherman; Kirk Veirs; Laura Worl

    2000-12-01

    This document captures relevant work performed in support of stabilization, packaging, and long term storage of plutonium metals and oxides. It concentrates on the issue of gas generation with specific emphasis on gas pressure and composition. Even more specifically, it summarizes the basis for asserting that materials loaded into a 3013 container according to the requirements of the 3013 Standard (DOE-STD-3013-2000) cannot exceed the container design pressure within the time frames or environmental conditions of either storage or transportation. Presently, materials stabilized and packaged according to the 3013 Standard are to be transported in certified packages (the certification process for the 9975 and the SAFKEG has yet to be completed) that do not rely on the containment capabilities of the 3013 container. Even though no reliance is placed on that container, this document shows that it is highly likely that the containment function will be maintained not only in storage but also during transportation, including hypothetical accident conditions. Further, this document, by summarizing materials-related data on gas generation, can point those involved in preparing Safety Analysis Reports for Packages (SARPs) to additional information needed to assess the ability of the primary containment vessel to contain the contents and any reaction products that might reasonably be produced by the contents.

  9. A new model involving ethylene, nitric oxide and Fe to explain the regulation of Fe-acquisition genes in Strategy I plants.

    PubMed

    García, María J; Suárez, Vicente; Romera, Francisco J; Alcántara, Esteban; Pérez-Vicente, Rafael

    2011-05-01

    In previous work it has been shown that both ethylene and NO (nitric oxide) participate in a similar way in the up-regulation of several Fe-acquisition genes of Arabidopsis and other Strategy I plants. This raises the question as to whether NO acts through ethylene or ethylene acts through NO, or whether both act in conjunction. One possibility is that NO could increase ethylene production. Conversely, ethylene could increase NO production. By using Arabidopsis and cucumber plants, we have found that both possibilities occur: NO greatly induces the expression in roots of genes involved in ethylene synthesis: AtSAM1, AtSAM2, AtACS4, AtACS6, AtACO1, AtACO2, AtMTK; CsACS2 and CsACO2; on the other hand, ethylene greatly enhances NO production in the subapical region of the roots. These results suggest that each substance influences the production of the other and that both substances could be necessary for up-regulation of Fe-acquisition genes. This has been further confirmed in experiments with simultaneous application of the NO donor GSNO (S-nitrosoglutathione) and ethylene inhibitors; or with simultaneous application of the ethylene precursor ACC (1-aminocyclopropane-1-carboxylic acid) and an NO scavenger. Both GSNO and ACC enhanced ferric reductase activity in control plants, but not in those plants simultaneously treated with the ethylene inhibitors or the NO scavenger, respectively. To explain all these results and previous ones we have proposed a new model involving ethylene, NO, and Fe in the up-regulation of Fe-acquisition genes of Strategy I plants. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  10. Fundamentals of Mercury Oxidation in Flue Gas

    SciTech Connect

    JoAnn S. Lighty; Geoffrey Silcox; Andrew Fry; Joseph Helble; Balaji Krishnakumar

    2006-07-31

    The objective of this project is to understand the importance of and the contribution of gas-phase and solid-phase coal constituents in the mercury oxidation reactions. The project involves both experimental and modeling efforts. The team is comprised of the University of Utah, Reaction Engineering International, and the University of Connecticut. The objective is to determine the experimental parameters of importance in the homogeneous and heterogeneous oxidation reactions; validate models; and, improve existing models. Parameters to be studied include HCl, NO{sub x}, and SO{sub 2} concentrations, ash constituents, and temperature. This report summarizes Year 3 results for the experimental and modeling tasks. Experiments have been completed on the effects of chlorine. However, the experiments with sulfur dioxide and NO, in the presence of water, suggest that the wet-chemistry analysis system, namely the impingers, is possibly giving erroneous results. Future work will investigate this further and determine the role of reactions in the impingers on the oxidation results. The solid-phase experiments have not been completed and it is anticipated that only preliminary work will be accomplished during this study.

  11. 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.

  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. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  13. Ethylene mediates brassinosteroid-induced stomatal closure via Gα protein-activated hydrogen peroxide and nitric oxide production in Arabidopsis.

    PubMed

    Shi, Chenyu; Qi, Cheng; Ren, Hongyan; Huang, Aixia; Hei, Shumei; She, Xiaoping

    2015-04-01

    Brassinosteroids (BRs) are essential for plant growth and development; however, whether and how they promote stomatal closure is not fully clear. In this study, we report that 24-epibrassinolide (EBR), a bioactive BR, induces stomatal closure in Arabidopsis (Arabidopsis thaliana) by triggering a signal transduction pathway including ethylene synthesis, the activation of Gα protein, and hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) production. EBR initiated a marked rise in ethylene, H(2)O(2) and NO levels, necessary for stomatal closure in the wild type. These effects were abolished in mutant bri1-301, and EBR failed to close the stomata of gpa1 mutants. Next, we found that both ethylene and Gα mediate the inductive effects of EBR on H(2)O(2) and NO production. EBR-triggered H(2)O(2) and NO accumulation were canceled in the etr1 and gpa1 mutants, but were strengthened in the eto1-1 mutant and the cGα line (constitutively overexpressing the G protein α-subunit AtGPA1). Exogenously applied H(2)O(2) or sodium nitroprusside (SNP) rescued the defects of etr1-3 and gpa1 or etr1 and gpa1 mutants in EBR-induced stomatal closure, whereas the stomata of eto1-1/AtrbohF and cGα/AtrbohF or eto1-1/nia1-2 and cGα/nia1-2 constructs had an analogous response to H(2)O(2) or SNP as those of AtrbohF or Nia1-2 mutants. Moreover, we provided evidence that Gα plays an important role in the responses of guard cells to ethylene. Gα activator CTX largely restored the lesion of the etr1-3 mutant, but ethylene precursor ACC failed to rescue the defects of gpa1 mutants in EBR-induced stomatal closure. Lastly, we demonstrated that Gα-activated H(2)O(2) production is required for NO synthesis. EBR failed to induce NO synthesis in mutant AtrbohF, but it led to H(2)O(2) production in mutant Nia1-2. Exogenously applied SNP rescued the defect of AtrbohF in EBR-induced stomatal closure, but H(2)O(2) did not reverse the lesion of EBR-induced stomatal closure in Nia1-2. Together, our

  14. Small angle neutron scattering study of the conformation of poly(ethylene oxide) dissolved in deep eutectic solvents.

    PubMed

    Chen, Zhengfei; McDonald, Samila; FitzGerald, Paul; Warr, Gregory G; Atkin, Rob

    2017-11-15

    The conformation of poly(ethylene oxide) (PEO) in deep eutectic solvents (DESs) is determined by the polymer-solvent interactions, especially hydrogen bonding interactions. The hypothesis for this work is that the hydrogen bonding environment of a DES can be varied via changing the cation or hydrogen bond donor (HBD), and therefore the solvent quality for PEO; the anion species will also effect hydrogen bonding, but this is not examined here. Small angle neutron scattering (SANS) is used to probe the concentration dependent conformation of 36kDa PEO dissolved in DESs formed by mixing ethyl or butyl ammonium bromide with a molecular HBD (glycerol or ethylene glycol) in a 1:2 molar ratio. The radius of gyration (Rg), Flory exponent and crossover concentration (c(*)) from the dilute to the semi-dilute regime of PEO in the DESs revealed by SANS and Zimm plot analysis show that these DESs are moderately good solvents for PEO. When the ammonium alkyl chain length is increased, the hydrogen bond density per unit volume decreases, and with it the solvent quality for PEO. The solvent quality is improved when the HBD is changed from glycerol to ethylene glycol due to differences in the hydrogen bonding environment for PEO. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Toxicity of ethylene oxide on the lens and on leukocytes: an epidemiological study in hospital sterilisation installations.

    PubMed

    Deschamps, D; Leport, M; Laurent, A M; Cordier, S; Festy, B; Conso, F

    1990-05-01

    An epidemiological study was conducted in 55 subjects (mean age: 41) in hospitals to determine the prevalence of lens opacities and cataracts in workers exposed to ethylene oxide in six sterilisation units. The 21 exposed subjects over 45 were then compared with 16 non-exposed subjects, matched for age and sex. The relation between occupational exposure to ethylene oxide and white blood cell concentrations was also investigated. Lens opacities (independently of visual acuity) were observed in 19 of the 55 exposed. Among both exposed and non-exposed aged over 45, there were no significant differences with regard to the characteristics of lens opacities--prevalence (19 in the 21 exposed; 10 in the 16 non-exposed), distribution of the location, and importance and type (opalescence or discontinuous opacities). No link was found between the characteristics of the lens opacities and the characteristics of exposure: habitual exposure, measured between 0.06 and 39 ppm (cumulated in ppm-number of weekly hours-years) and accidental over-exposures (regular and irregular). For cataracts, defined by the association of lens opacities and a visual acuity less than 20/25 (this loss not being attributable to another cause), their prevalence differed significantly (p less than 0.05) between the exposed (six of 21) and the non-exposed (0 of 16); there was no relation between their existence and overexposures (the analysis for habitual exposure was not possible because of the small size of the sample). The risk of lens opacifications by ethylene oxide in cases of massive exposures as previously described could also exist during chronic exposure to low concentrations. It could be explained by saturation of protective mechanisms against alkylating action of this product. Linear relations were found between the logarithms of blood concentrations of polymorphoneutrophils (R=-0.54; p<0.005) and of lymphocytes (R=-0.45;p<0.05).

  16. Toxicity of ethylene oxide on the lens and on leukocytes: an epidemiological study in hospital sterilisation installations.

    PubMed Central

    Deschamps, D; Leport, M; Laurent, A M; Cordier, S; Festy, B; Conso, F

    1990-01-01

    An epidemiological study was conducted in 55 subjects (mean age: 41) in hospitals to determine the prevalence of lens opacities and cataracts in workers exposed to ethylene oxide in six sterilisation units. The 21 exposed subjects over 45 were then compared with 16 non-exposed subjects, matched for age and sex. The relation between occupational exposure to ethylene oxide and white blood cell concentrations was also investigated. Lens opacities (independently of visual acuity) were observed in 19 of the 55 exposed. Among both exposed and non-exposed aged over 45, there were no significant differences with regard to the characteristics of lens opacities--prevalence (19 in the 21 exposed; 10 in the 16 non-exposed), distribution of the location, and importance and type (opalescence or discontinuous opacities). No link was found between the characteristics of the lens opacities and the characteristics of exposure: habitual exposure, measured between 0.06 and 39 ppm (cumulated in ppm-number of weekly hours-years) and accidental over-exposures (regular and irregular). For cataracts, defined by the association of lens opacities and a visual acuity less than 20/25 (this loss not being attributable to another cause), their prevalence differed significantly (p less than 0.05) between the exposed (six of 21) and the non-exposed (0 of 16); there was no relation between their existence and overexposures (the analysis for habitual exposure was not possible because of the small size of the sample). The risk of lens opacifications by ethylene oxide in cases of massive exposures as previously described could also exist during chronic exposure to low concentrations. It could be explained by saturation of protective mechanisms against alkylating action of this product. Linear relations were found between the logarithms of blood concentrations of polymorphoneutrophils (R=-0.54; p<0.005) and of lymphocytes (R=-0.45;p<0.05). PMID:2357451

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

    PubMed

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

    2016-06-01

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

  18. Polar stationary phases based on poly(oligo ethylene glycol)diacrylates for capillary gas chromatography

    NASA Astrophysics Data System (ADS)

    Shiryaeva, V. E.; Popova, T. P.; Korolev, A. A.; Kanat'eva, A. Yu.; Kurganov, A. A.

    2017-08-01

    New stationary phases for capillary columns in GC are synthesized and studied. The phases are prepared by depositing oligo(ethylene glycol)diacrylates on the column walls and subsequent polymerization (crosslinking) in the presence of peroxide initiators. It is shown that stationary phases based on monomers with molecular weights of 10 kDa or higher exhibit separation properties similar to those of conventional stationary phases based on polyethylene glycol (PEG); however, their thermal stability is higher because they have a higher degree of crosslinking and a more ordered structure of the crosslinked polymers than the respective parameters of phases based on native PEG.

  19. V{sub 2}O{sub 5} xerogel-poly(ethylene oxide) hybrid material: Synthesis, characterization, and electrochemical properties

    SciTech Connect

    Guerra, Elidia M.; Ciuffi, Katia J.; Oliveira, Herenilton P. . E-mail: herepo@ffclrp.usp.br

    2006-12-15

    In this work, we report the synthesis, characterization, and electrochemical properties of vanadium pentoxide xerogel-poly(ethylene oxide) (PEO) hybrid materials obtained by varying the average molecular weight of the organic component as well as the components' ratios. The materials were characterized by X-ray diffraction, ultraviolet/visible and infrared spectroscopies, thermogravimetric analysis, scanning electron microscopy, electron paramagnetic resonance, and cyclic voltammetry. Despite the presence of broad and low intensity peaks, the X-ray diffractograms indicate that the lamellar structure of the vanadium pentoxide xerogel is preserved, with increase in the interplanar spacing, giving evidence of a low-crystalline structure. We found that the electrochemical behaviour of the hybrid materials is quite similar to that found for the V{sub 2}O{sub 5} xerogel alone, and we verified that PEO leads to stabilization and reproducibility of the Li{sup +} electrochemical insertion/de-insertion into the V{sub 2}O{sub 5} xerogel structure, which makes these materials potential components of lithium ion batteries. - Graphical abstract: The synthesis, structural and electrochemical properties of vanadium pentoxide xerogel-poly(ethylene oxide) hybrid materials have been described. Despite the presence of broad and low intensity peaks, the X-ray diffractograms indicate that the lamellar structure of the vanadium pentoxide xerogel is preserved. The cy voltammetry technique demonstrated that PEO intercalation provides an improvement in the electrochemical properties, mainly with respect to the lithium electroinsertion process into the oxide matrix.

  20. Fluorosilane compounds with oligo(ethylene oxide) substituent as safe electrolyte solvents for high-voltage lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Wang, Jinglun; Mai, Yongjin; Luo, Hao; Yan, Xiaodan; Zhang, Lingzhi

    2016-12-01

    Two fluorosilanes with oligo(ethylene oxide) unites were synthesized through hydrosilylation of chlorosilane with allyl substituted oligo(ethylene oxide) ether followed by fluorination with potassium fluoride. The synthesized fluorosilane compounds exhibited lower viscosity, higher dielectric constant and higher oxidation potential, compared with their non-fluorination counterparts. Difluoro(3-(2-(2-methoxyethoxy)ethoxy)propyl)methylsilane (DFSM2), one of the two compounds, was evaluated as high-voltage and thermal stable electrolyte co-solvent with the conventional carbonate-based electrolytes. Using an optimized electrolyte of 1M LiPF6 in EC/DFSM2/EMC (2/3/5 in vol.) with addition of 5 wt% fluoroethylene carbonate (FEC), high-voltage LiCoO2(LCO)/graphite full cell displayed outstanding cycling stability of 92.5% capacity retention after 135 cycles at 4.4 V upper cutoff voltage. Characterized by differential scanning calorimetry (DSC) analysis, the DFSM2-based electrolyte demonstrated higher thermal stability with lithiated graphite anode and delithiated LCO cathode, thus better safety feature compared with the conventional electrolyte.