Science.gov

Sample records for 1-3 perfluorinated fused

  1. Short and general procedure for synthesizing cis-1,2-fused 1,3-oxathiolan-, 1,3-oxaselenolan-, and 1,3-oxazolidin-2-imine carbohydrate derivatives.

    PubMed

    Castilla, Javier; Marín, Irene; Matheu, M Isabel; Díaz, Yolanda; Castillón, Sergio

    2010-01-15

    Novel cis-1,2-fused 1,3-oxathiolan-, 1,3-oxaselenolan-, and 1,3-oxazolidin-2-imine carbohydrate derivatives have been prepared by treatment of the corresponding 1,2-anhydrosugars with potassium thiocyanate, potassium selenocyanate, and sodium cyanamide, respectively. The procedure is compatible with several protecting groups such as acyl, benzyl, and silyl and also with sugars of different configurations.

  2. Perfluorinated Compounds

    EPA Science Inventory

    Perfluorinated compounds such as the perfluoroalkyl acids (PFAAs) and their derivatives are important man-made chemicals that have wide consumer and industrial applications. They are relatively contemporary chemicals, being in use only since the 1950s, and until recently, have be...

  3. Novel synthesis of fused isoxazolidines via a palladium catalysed allene insertion-intramoleculer 1,3-dipolar cycloaddition cascade reaction.

    PubMed

    Aftab, Tajassas; Grigg, Ronald; Ladlow, Mark; Sridharan, Visuvanathar; Thornton-Pett, Mark

    2002-08-21

    A one pot, three component palladium catalysed allenation of aryl iodides, in combination with a nitrone cycloaddition, leads to formation of fused isoxazolidines, creating two rings, two stereocentres and one tetrasubstituted carbon centre.

  4. Synthesis, antimicrobial, antiquorum-sensing, antitumor and cytotoxic activities of new series of fused [1,3,4]thiadiazoles.

    PubMed

    El-Gohary, Nadia S; Shaaban, Mona I

    2013-05-01

    New series of [1,3,4]thiadiazolo[3,2-a]pyrimidines, benzo[h][1,3,4]thiadiazolo[2,3-b]quinazolines, benzothiadiazolotriazocine, and imidazo[2,1-b][1,3,4]thiadiazoles have been synthesized and characterized by analytical and spectrometrical methods (IR, MS, (1)H and (13)C NMR). Twenty of the synthesized compounds were screened for antibacterial activity against Escherichia coli, Staphylococcus aureus and Bacillus cereus. They were found to be either moderately active, slightly active or inactive against the tested microorganisms. The antifungal activity of these compounds were also tested against Candida albicans, Aspergillus fumigatus 293 and Aspergillus flavus 3375. Compounds 3g, h showed potent antifungal activity against C. albicans. In addition, the same compounds were tested for antiquorum-sensing activity against Chromobacterium violacium ATCC 12472, where compounds 3b,c, 3f-h, 6b-d, 9, 10 and 12 demonstrated acceptable activity. Compounds 3d, 9 and 10 were screened for antitumor activity at National Cancer Institute, USA. The in vitro cytotoxic activity of eighteen of the synthesized compounds was studied by brine shrimp lethality bioassay, and results indicated that compounds 6c, 13, 3h, 6d and 3d have the highest cytotoxic activity.

  5. Highly regioselective 1,3-dipolar cycloaddition of diphenylnitrilimine to Sc3N@I(h)-C80 affording a very stable, unprecedented pyrazole-ring fused derivative of endohedral metallofullerenes.

    PubMed

    Liu, Bin; Cong, Hailin; Li, Xiaofang; Yu, Bing; Bao, Lipiao; Cai, Wenting; Xie, Yunpeng; Lu, Xing

    2014-10-28

    Formation of a very stable, unprecedented pyrazole-ring fused derivative of endohedral metallofullerenes was achieved by the first 1,3-dipolar cycloaddition reaction of Sc3N@C80 with diphenylnitrilimine in a highly regioselective manner.

  6. N,N,N',N'-tetramethyl-1,3-butanediamine as effective running electrolyte additive for efficient electrophoretic separation of basic proteins in bare fused-silica capillaries.

    PubMed

    Corradini, D; Cannarsa, G

    1995-04-01

    The effect of N,N,N',N'-tetramethyl-1,3-butanediamine (TMBD) in the running electrolyte on the electroosmotic flow and the migration behavior of four standard basic proteins in bare fused-silica capillaries was examined at pH 4.0, 5.5, and 6.5. Depending on the electrolyte pH and additive concentration the electroosmotic flow was either cathodic or anodic. A similar Langmuirian-type dependence of the electroosmotic flow on the concentration of TMBD in the running electrolyte was found at the three experimented pH values, which may be indicative of the specific adsorption of the additive in the immobilized region of the electric double layer at the interface between the capillary wall and the electrolyte solution. Electrophoretic separations of the four standard basic proteins performed at the three above pH values, showed well-resolved, efficient and symmetric peaks, demonstrating the utility of this additive for protein electrophoresis in bare fused-silica capillaries. The variations in separation efficiency, peak capacity, resolution and reproducibility of migration times as a function of the additive concentration at pH 6.5 were also examined.

  7. PERSISTENT PERFLUORINATED ORGANIC COMPOUNDS

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have gained notoriety in the recent past. Global distribution of PFCs in wildlife, environmental samples and humans has sparked a recent increase in new investigations concerning PFCs. Historically PFCs have been used in a wide variety of consume...

  8. Perfluorinated compounds and subfecundity in pregnant women

    PubMed Central

    Whitworth, Kristina W.; Haug, Line S.; Baird, Donna D.; Becher, Georg; Hoppin, Jane A.; Skjaerven, Rolv; Thomsen, Cathrine; Eggesbo, Merete; Travlos, Gregory; Wilson, Ralph; Longnecker, Matthew P.

    2011-01-01

    Background Perfluorinated compounds are ubiquitous pollutants; epidemiologic data suggest they may be associated with adverse health outcomes, including subfecundity. We examined subfecundity in relation to two perfluorinated compounds, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). Methods This case-control analysis included 910 women enrolled in the Norwegian Mother and Child Cohort Study in 2003 and 2004. Around gestational week 17, women reported their time to pregnancy and provided blood samples. Cases consisted of 416 women with a time to pregnancy greater than 12 months, considered subfecund. Plasma concentrations of perfluorinated compounds were analyzed using liquid chromatography-mass spectrometry. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for each pollutant quartile using logistic regression. Estimates were further stratified by parity. Results The median plasma concentration of PFOS was 13.0 ng/ml (interquartile range [IQR]=10.3-16.6 ng/ml) and of PFOA was 2.2 ng/ml (IQR=1.7-3.0 ng/ml). The relative odds of subfecundity among parous women was 2.1 (95% CI=1.2-3.8) for the highest PFOS quartile and 2.1 (1.0-4.0) for the highest PFOA quartile. Among nulliparous women, the respective relative odds were 0.7 (0.4-1.3) and 0.5 (0.2-1.2). Conclusion Previous studies suggest that the body burden of perfluorinated compounds decreases during pregnancy and lactation through transfer to the fetus and to breast milk. Afterwards, the body burden may rise again. Among parous women, increased body burden may be due to a long interpregnancy interval rather than the cause of a long time to pregnancy. Therefore, data from nulliparous women may be more informative regarding toxic effects of perfluorinated compounds. Our results among nulliparous women did not support an association with subfecundity. PMID:22081060

  9. Regio- and stereoselective synthesis of pregnane-fused isoxazolines by nitril-oxide/alkene 1,3-dipolar cycloaddition and an evaluation of their cell-growth inhibitory effect in vitro

    NASA Astrophysics Data System (ADS)

    Mótyán, Gergő; Baji, Ádám; Zupkó, István; Frank, Éva

    2016-04-01

    Efficient syntheses of some pregnane-fused isoxazolines from 16-dehydropregnenolone acetate with different arylnitrile oxides were carried out by 1,3-dipolar cycloadditions. The intermolecular ring-closures occurred in a highly regio- and stereoselective manner permitting the formation of a single 16α,17α-condensed diastereomer in which the O terminus of the nitrile oxide dipole is attached to C-17 of the sterane core. The conversions were found to be affected significantly by the electronic character of the substituents on the aromatic moiety of the 1,3-dipoles. Deacetylation of the primary products resulted in the corresponding 3β-OH analogs. All of the synthesized compounds were subjected to in vitro pharmacological studies for the determination of their antiproliferative effects on four breast cancer cell lines (MCF7, T47D, MDA-MB-231 and MDA-MB-361).

  10. Regioselective construction of 1,3-diazaheterocycle fused [1,2-a][1,8]naphthyridine derivatives via cascade reaction of quinolines with heterocyclic ketene aminals: a joint experimental-computational approach.

    PubMed

    Zhang, Yi-Chuan; Liu, Zhi-Cheng; Yang, Rui; Zhang, Ji-Hong; Yan, Sheng-Jiao; Lin, Jun

    2013-11-14

    A one-step, transition-metal-free protocol, involving facile post-treatment, for the regioselective synthesis of 1,3-diazaheterocycle fused [1,2-a][1,8]naphthyridine derivatives (3) from 2-chloroquinoline-3-carbaldehydes (ClQuAlds) (1) and heterocyclic ketene aminals (HKAs) (2) was developed via a joint experimental-computational approach. The computational prediction of the reactivity of two series of synthons was applied in the process of optimizing the reaction conditions, which relied on density functional theory (DFT) calculations together with concepts of frontier molecular orbital (FMO) theory and quantitative structure-reactivity relationship (QSRR) presumptions. The combined results enabled the proposal of a pre-synthetic prediction of global reactivity. The fully consistent results of the synthetic experiments with the in silico evaluation confirmed the rationality, effectiveness, and practicability of the new strategy. Notably, the joint method is not limited to the laboratory, but has applications ranging from routine to industry. This approach is likely to yield numerous insights to accelerate HKA-related synthetic chemistry that can be extended to numerous heterocycles. It thus opens up a novel entry towards rapidly investigating the reactivity of novel synthons with unique properties, a further step towards exploiting cascade reactions by avoiding the futile waste of time and resources. PMID:24057033

  11. FUSE - Australia

    ERIC Educational Resources Information Center

    South Australian Science Teachers Journal, 1974

    1974-01-01

    Announces the establishment of a division of FUSE in Australia, at Sturt College of Advanced Education, for the purpose of disseminating the concept of unified science and to facilitate the development of unified science programs. (BR)

  12. Perfluorinated Compounds In The Ohio River Basin

    EPA Science Inventory

    Contaminants of emerging concern (CECs) in waterways include pharmaceuticals and personal care products (PPCPs), alkylphenols, endocrine disrupting chemicals (EDCs) and perfluorinated alkyl compounds (PFCs). Their distributions and persistence in the aquatic environment remain p...

  13. Brominated Flame Retardants and Perfluorinated Chemicals

    EPA Science Inventory

    Brominated flame retardants (BFRs) and perfluorinated chemicals (PFCs) belong to a large class of chemicals known as organohalogens. It is believed that both BFRs and PFCs saved lives by reducing flammability of materials commonly used and bactericidal (biocidal) properties. Thes...

  14. ANALYSIS OF FISH HOMOGENATES FOR PERFLUORINATED COMPOUNDS

    EPA Science Inventory

    Perfluorinated compounds (PFCs) which include PFOS and PFOA are widely distributed in wildlife. Whole fish homogenates were analyzed for PFCs from the upper Mississippi, the Missouri and the Ohio rivers. Methods development, validation data, and preliminary study results will b...

  15. Guard For Fuse Caps

    NASA Technical Reports Server (NTRS)

    Atwell, D. C.

    1985-01-01

    L-shaped guard attached to fuse holder. Guard prevents casual tampering with fuses in electrical junction box or fuse block. Protects fuses from being damaged by handling or by rope or string used to secure them. With fuse-cap guard, only responsible people have access to fuses.

  16. PERFLUORINATED ORGANIC COMPOUND EXPOSURE ASSESSMENT RESEARCH

    EPA Science Inventory

    A wide range of perfluorinated organic compounds (PFCs) has been used in a variety of industrial processes and consumer products. The most commonly studied PFCs include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), but there are many more compounds in this c...

  17. (CHINA) PERFLUORINATED ORGANIC COMPOUND EXPOSURE ASSESSMENT RESEARCH

    EPA Science Inventory

    A wide range of perfluorinated organic compounds (PFCs) has been used in a variety of industrial processes and consumer products. The most commonly studied PFCs include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), but there are many more compounds in this c...

  18. Perfluorinated Compounds: Emerging POPs with Potential Immunotoxicity

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have been recognized as an important class of environmental contaminants commonly detected in blood samples of both wildlife and humans. These compounds have been in use for more than 60 years as surface treatment chemicals, polymerization aids, an...

  19. Effects of perfluorinated chemicals on adipocyte development

    EPA Science Inventory

    Obesity is a growing concern in the US population. Current interest is high in the role played by environmental factors called obesogens that may contribute to obesity through developmental exposure. One class of potential obesogens is the family of perfluorinated chemicals used ...

  20. 21 CFR 173.21 - Perfluorinated ion exchange membranes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Perfluorinated ion exchange membranes. 173.21... Polymer Adjuvants for Food Treatment § 173.21 Perfluorinated ion exchange membranes. Substances identified in paragraph (a) of this section may be safely used as ion exchange membranes intended for use in...

  1. Perfluorinated resinsulfonic acid--a catalyst for certain organic reactions

    SciTech Connect

    Etlis, V.S.; Beshenova, E.P.; Semenova, E.A.; Shomina, F.N.; Dreiman, N.A.; Balaev, G.A.

    1986-09-10

    The purpose of this work was to examine the possibility of using, as a catalyst in certain organic reactions, the perfluorinated resinsulfonic acid F-4SK in the H form, which is an analog of the perfluorinated resinsulfonic acid Nafion-H.

  2. Perfluorinated Alkyl Compounds: Challenges To Develop Robust And Reliable Methods

    EPA Science Inventory

    An increasing number of studies have been conducted to investigate the environmental distribution of perfluorinated alkyl compounds (PFCs), some of which are known to be toxic in laboratory studies. Despite growing public concerns, environmental monitoring data are still limited...

  3. Determination of Perfluorinated Compounds in the Upper Mississippi River Basin

    EPA Science Inventory

    Despite ongoing efforts to develop robust analytical methods for the determination of perfluorinated compounds (PFCs) such as perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA) in surface water, comparatively little has been published on method performance, and the...

  4. Developmental Toxicity of Perfluorinated Phosphonic Acids in Mice

    EPA Science Inventory

    Perfluorinated phosphonic acids (PFPAs) are a third member of the perfluoroalkyl acid (PFAA) family, and are structurally similar to the perfluoroalkyl sulfonates and perfluoroalkyl carboxylates. PFPAs are used primarily as a surfactant defoaming agent in pesticide production. Re...

  5. Dielectric Barrier Discharge Ionization of Perfluorinated Compounds.

    PubMed

    Schütz, Alexander; Brandt, Sebastian; Liedtke, Sascha; Foest, Daniel; Marggraf, Ulrich; Franzke, Joachim

    2015-11-17

    The soft ionization ability based on plasma-jet protonation of molecules initiated by a dielectric barrier discharge ionization source (DBDI) is certainly an interesting application for analytical chemistry. Since the change of an applied sinusoidal voltage may lead to different discharge modes the applied discharge was powered by a square wave generator in order to get a homogeneous plasma. It is known that besides the protonation [M+H](+) of unpolar as well as some polar molecules the homogeneous DBDI can be used to ionize molecules directly [M](+). Here we prove that the DBDI can be applied to exchange fluorine by oxygen of perfluorinated compounds (PFC). PFC are organofluorine compounds with carbon-fluorine and carbon-carbon bonds only but no carbon-hydrogen bonds. While the position of the introduction into the plasma-jet is essential, PFC can be measured in the negative mass spectrometer (MS) mode.

  6. ANALYSIS OF PERFLUORINATED CARBOXYLIC ACIDS IN SOILS II: OPTIMIZATION OF CHROMATOGRAPHY AND EXTRACTION

    EPA Science Inventory

    With the objective of detecting and quantitating low concentrations of perfluorinated carboxylic acids (PFCAs), including perfluorinated octanoic acid (PFOA), in soils, we compared the analytical suitability of liquid chromatography columns containing three different stationary p...

  7. Self-healing fuse

    NASA Technical Reports Server (NTRS)

    Jones, N. D.; Kinsinger, R. E.; Harris, L. P.

    1974-01-01

    Fast-acting current limiting device provides current overload protection for vulnerable circuit elements and then re-establishes conduction path within milliseconds. Fuse can also perform as fast-acting switch to clear transient circuit overloads. Fuse takes advantage of large increase in electrical resistivity that occurs when liquid metal vaporizes.

  8. ANALYSIS OF PERFLUORINATED CARBOXYLIC ACIDS IN SOILS: DETECTION AND QUANTITATION ISSUES AT LOW CONCENTRATIONS

    EPA Science Inventory

    Methods were developed for the extraction from soil, identification, confirmation and quantitation by LC/MS/MS of trace levels of perfluorinated octanoic acid (PFOA), perfluorinated nonanoic acid (PFNA) and perfluorinated decanoic acid (PFDA). Whereas PFOA, PFNA and PFDA all can...

  9. A comparative study of the physicochemical properties of perfluorinated and hydrogenated amphiphiles.

    PubMed

    Blanco, Elena; González-Pérez, Alfredo; Ruso, Juan M; Pedrido, Rosa; Prieto, Gerardo; Sarmiento, Félix

    2005-08-01

    In this work we studied and compared the physicochemical properties of perfluorinated (sodium perfluoroheptanoate, C7FONa, and perfluorooctanoate, C8FONa) and hydrogenated (sodium octanoate, C8HONa, decanoate, C10HONa, and dodecanoate, C12HONa) amphiphiles. First, we determined their Krafft points to study the solubility and appropriate temperature range of micellization of these compounds. The critical micelle concentration (cmc) and ionization degree of micellization (beta) as a function of temperature (T) were estimated from conductivity data. Plots of cmc vs T appear to follow the typical U-shaped curve with a minimum T(min). The results show that the surfactants with CF2/CH2 ratio of 1.5 between alkyl chains (C12HONa-C8FONa and C10HONa-C7FONa) have nearly the same minimum value for cmc against temperature. The comparison between the cmc of hydrogenated amphiphiles and the corresponding perfluorinated amphiphiles must be done at this point. Thermodynamic functions of micellization were obtained by applying different theoretical models and choosing the one that best fit our experimental data. Although perfluorinated and hydrogenated amphiphiles present similar thermodynamic behavior, we have found a variation of 1.3 to 1.7 in the CF2/CH2 ratio, which did not remain constant with temperature. In the second part of this study the apparent molar volumes and adiabatic compressibilities were determined from density and ultrasound velocity measurements. Apparent molar volumes at infinite dilution presented the ratio 1.5 between alkyl chains again. However, apparent molar volumes upon micellization for sodium perfluoroheptanoate indicated a different aggregation pattern.

  10. Uptake of perfluorinated compounds by plants grown in nutrient solution.

    PubMed

    García-Valcárcel, A I; Molero, E; Escorial, M C; Chueca, M C; Tadeo, J L

    2014-02-15

    The uptake rates of three perfluorinated carboxylates and three perfluorinated sufonates by a grass (B diandrus) grown in nutrient solution at two different perfluorinated compounds (PFCs) concentrations were assessed. Grass can be ingested by grazing animals causing the PFCs to enter the food chain, which is a pathway of human exposure to these compounds. A rapid and miniaturized method was developed to determine PFCs in plants, based on a matrix solid-phase dispersion (MSPD) extraction procedure followed by quantitation by HPLC-MS/MS with an MQL in the range from 1 to 9 ng/g. An increase of PFCs levels in plant was observed along the exposure time. Differences in uptake for studied perfluorinated carboxylates were found, showing a decrease with carbon chain length (from 3027 to 1,167 ng/g at the end of assay), whereas no significant differences in absorption were obtained between perfluorinated sulfonates (about 1,700 ng/g). Initially, higher PFC transfer factors (ratio between concentration in plant and concentration in initial nutrient solution) were obtained for plants growing in the nutrient solution at the highest PFC concentration, but these factors became similar with time to plants exposed to the lowest concentration.

  11. Uptake of perfluorinated compounds by plants grown in nutrient solution.

    PubMed

    García-Valcárcel, A I; Molero, E; Escorial, M C; Chueca, M C; Tadeo, J L

    2014-02-15

    The uptake rates of three perfluorinated carboxylates and three perfluorinated sufonates by a grass (B diandrus) grown in nutrient solution at two different perfluorinated compounds (PFCs) concentrations were assessed. Grass can be ingested by grazing animals causing the PFCs to enter the food chain, which is a pathway of human exposure to these compounds. A rapid and miniaturized method was developed to determine PFCs in plants, based on a matrix solid-phase dispersion (MSPD) extraction procedure followed by quantitation by HPLC-MS/MS with an MQL in the range from 1 to 9 ng/g. An increase of PFCs levels in plant was observed along the exposure time. Differences in uptake for studied perfluorinated carboxylates were found, showing a decrease with carbon chain length (from 3027 to 1,167 ng/g at the end of assay), whereas no significant differences in absorption were obtained between perfluorinated sulfonates (about 1,700 ng/g). Initially, higher PFC transfer factors (ratio between concentration in plant and concentration in initial nutrient solution) were obtained for plants growing in the nutrient solution at the highest PFC concentration, but these factors became similar with time to plants exposed to the lowest concentration. PMID:24291554

  12. Electrochemical oxidation of perfluorinated compounds in water.

    PubMed

    Niu, Junfeng; Li, Yang; Shang, Enxiang; Xu, Zesheng; Liu, Jinzi

    2016-03-01

    Perfluorinated compounds (PFCs) are persistent and refractory organic pollutants that have been detected in various environmental matrices and municipal wastewater. Electrochemical oxidation (EO) is a promising remediation technique for wastewater contaminated with PFCs. A number of recent studies have demonstrated that the "non-active" anodes, including boron-doped diamond, tin oxide, and lead dioxide, are effective in PFCs elimination in wastewater due to their high oxygen evolution potential. Many researchers have conducted experiments to investigate the optimal conditions (i.e., potential, current density, pH value, plate distance, initial PFCs concentration, electrolyte, and other factors) for PFCs elimination to obtain the maximal elimination efficiency and current efficiency. The EO mechanism and pathways of PFCs have been clearly elucidated, which undergo electron transfer, Kolbe decarboxylation or desulfonation, hydrolysis, and radical reaction. In addition, the safety evaluation and energy consumption evaluation of the EO technology have also been summarized to decrease toxic ion release from electrode and reduce the cost of this technique. Although the ultrasonication and hydrothermal techniques combined with the EO process can improve the removal efficiency and current efficiency significantly, these coupled techniques have not been commercialized and applied in industrial wastewater treatment. Finally, key challenges facing EO technology are listed and the directions for further research are pointed out (such as combination with other techniques, treatment for natural waters contaminated by low levels of PFCs, and reactor design).

  13. PERFLUORINATED COMPOUNDS: EMERGING POPs WITH POTENTIAL IMMUNOTOXICITY

    PubMed Central

    Corsini, Emanuela; Luebke, Robert W.; Germolec, Dori R.; DeWitt, Jamie C.

    2015-01-01

    Perfluorinated compounds (PFCs) have been recognized as an important class of environmental contaminants commonly detected in blood samples of both wildlife and humans. These compounds have been in use for more than 60 years as surface treatment chemicals, polymerization aids, and surfactants. They possess a strong carbon-fluorine bond, which leads to their environmental persistence. There is evidence from both epidemiology and laboratory studies that PFCs may be immunotoxic, affecting both cell-mediated and humoral immunity. Reported effects of PFCs include decreased spleen and thymus weights and cellularity, reduced antibody production, reduced survival after influenza infection, and altered cytokine production. Immunosuppression is a critical effect associated with exposure to PFCs, as it has been reported to reduce antibody responses to vaccination in children. Mounting evidence suggests that immunotoxicity in experimental animals can occur at serum concentrations below, within, or just above the reported range for highly exposed humans and wildlife. Considering bioaccumulation and exposure to multiple PFCs, the risk of immunotoxicity for humans and wildlife cannot be discounted. This review will discuss current and recently published work exploring the immunomodulatory effects of PFCs in experimental animals and humans. PMID:24503008

  14. Groundwater pollution by perfluorinated surfactants in Tokyo.

    PubMed

    Murakami, Michio; Kuroda, Keisuke; Sato, Nobuyuki; Fukushi, Tetsuo; Takizawa, Satoshi; Takada, Hideshige

    2009-05-15

    Perfluorinated surfactants (PFSs) in groundwater were analyzed to reveal their distribution and sources. Sixteen groundwater and spring samples were collected from the Tokyo metropolitan area, and nine PFSs, including perfluorooctane-sulfonate (PFOS) and perfluorooctanoate (PFOA), were analyzed by liquid chromatography-tandem mass spectrometry. A column test using artificial street runoff was also performed to study their behavior. PFSs were detected in all groundwater samples, some at concentrations comparable to those in wastewater and street runoff, suggesting widespread contamination of groundwater by PFSs. In particular, PFOS -was more abundant in groundwater than in rivers, wastewater, and street runoff. This was attributed to its production from the degradation of its precursors, as supported by the column test. The occurrence of short-chain perfluorocarboxylates (PFCAs) in groundwater was also consistent with the results of the column test, showing that limited amounts of short-chain PFCAs were removed by soil, as the efficiency of removal increased with the chain length. We evaluated the contributions of PFCAs from wastewater and surface runoff to groundwater by using two indicators, the long/(short + long) ratio and the even(even + odd) ratio. Both ratios showed good agreement in their calculated contributions in heavily contaminated groundwater where breakthroughs likely occurred. Wastewater and surface runoff contributed to 54-86% and 16-46% of PFCAs, respectively, in groundwater.

  15. Electrochemical oxidation of perfluorinated compounds in water.

    PubMed

    Niu, Junfeng; Li, Yang; Shang, Enxiang; Xu, Zesheng; Liu, Jinzi

    2016-03-01

    Perfluorinated compounds (PFCs) are persistent and refractory organic pollutants that have been detected in various environmental matrices and municipal wastewater. Electrochemical oxidation (EO) is a promising remediation technique for wastewater contaminated with PFCs. A number of recent studies have demonstrated that the "non-active" anodes, including boron-doped diamond, tin oxide, and lead dioxide, are effective in PFCs elimination in wastewater due to their high oxygen evolution potential. Many researchers have conducted experiments to investigate the optimal conditions (i.e., potential, current density, pH value, plate distance, initial PFCs concentration, electrolyte, and other factors) for PFCs elimination to obtain the maximal elimination efficiency and current efficiency. The EO mechanism and pathways of PFCs have been clearly elucidated, which undergo electron transfer, Kolbe decarboxylation or desulfonation, hydrolysis, and radical reaction. In addition, the safety evaluation and energy consumption evaluation of the EO technology have also been summarized to decrease toxic ion release from electrode and reduce the cost of this technique. Although the ultrasonication and hydrothermal techniques combined with the EO process can improve the removal efficiency and current efficiency significantly, these coupled techniques have not been commercialized and applied in industrial wastewater treatment. Finally, key challenges facing EO technology are listed and the directions for further research are pointed out (such as combination with other techniques, treatment for natural waters contaminated by low levels of PFCs, and reactor design). PMID:26745381

  16. The FUSE Approach

    ERIC Educational Resources Information Center

    Showalter, Victor M.

    1973-01-01

    A description of the present position of the FUSE organization relative to the development of unified science programs is discussed, including the related purposes and directions that characterize the newly established center. (DF)

  17. 21 CFR 173.21 - Perfluorinated ion exchange membranes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Perfluorinated ion exchange membranes. 173.21... ion exchange membranes. Substances identified in paragraph (a) of this section may be safely used as ion exchange membranes intended for use in the treatment of bulk quantities of liquid food under...

  18. 21 CFR 173.21 - Perfluorinated ion exchange membranes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Perfluorinated ion exchange membranes. 173.21... ion exchange membranes. Substances identified in paragraph (a) of this section may be safely used as ion exchange membranes intended for use in the treatment of bulk quantities of liquid food under...

  19. 21 CFR 173.21 - Perfluorinated ion exchange membranes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Perfluorinated ion exchange membranes. 173.21... ion exchange membranes. Substances identified in paragraph (a) of this section may be safely used as ion exchange membranes intended for use in the treatment of bulk quantities of liquid food under...

  20. 21 CFR 173.21 - Perfluorinated ion exchange membranes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Perfluorinated ion exchange membranes. 173.21... ion exchange membranes. Substances identified in paragraph (a) of this section may be safely used as ion exchange membranes intended for use in the treatment of bulk quantities of liquid food under...

  1. Tropone-fused carbaporphyrins.

    PubMed

    Lash, Timothy D; Gilot, Gean C; AbuSalim, Deyaa I

    2014-10-17

    Previous attempts to prepare tropone-fused carbaporphyrins by reacting peroxides with azuliporphyrins under basic conditions afforded benzocarbaporphyrins instead. In this study, a methoxyazulitripyrrane condensed with a pyrrole dialdehyde in the presence of TFA, followed by oxidation with ferric chloride, to give a tropone-fused carbaporphyrin following a spontaneous demethylation. The porphyrinoid gave a modified UV-vis spectrum showing multiple bands in the Soret region, and the proton NMR spectrum showed that it has a reduced diamagnetic ring current in comparison to other carbaporphyrins. The tropone-fused derivative failed to react with tert-butyl hydroperoxide and potassium hydroxide, demonstrating that this type of structure is not an intermediate in the formation of benzocarbaporphyrins. However, the reaction with silver(I) acetate gave the corresponding silver(III) complex. Condensation of the methoxyazulitripyrrane with 2,5-thiophenedicarbaldehyde gave a related tropone-fused thiacarbaporphyrin together with a methoxythiaazuliporphyrin. Treatment of the carbaporphyrins with DBU resulted in the formation of anionic species, while addition of acid afforded dicationic structures. DFT studies were performed on a series of tautomers, protonated species, and anionic structures related to these tropone-fused carbaporphyrins, and NICS calculations were carried out. These results allowed favorable conjugation pathways to be identified. In addition, these studies predicted that protonation initially occurs on the carbonyl moiety rather than on the expected interior pyrrolenine nitrogen atom. PMID:25229306

  2. Self-healing fuse development

    NASA Technical Reports Server (NTRS)

    Jones, N. D.; Kinsinger, R. E.; Harris, L. P.

    1973-01-01

    The mercury-filled self-healing fuses developed for this program afford very good protection from circuit faults with rapid reclosure. Fuse performance and design parameters have been characterized. Life tests indicate a capability of 500 fuse operations. Fuse ratings are 150 v at 5, 15, 25 and 50 circuit A. A series of sample fuses using alumina and beryllia insulation have been furnished to NASA for circuit evaluation.

  3. A global survey of perfluorinated acids in oceans.

    PubMed

    Yamashita, Nobuyoshi; Kannan, Kurunthachalam; Taniyasu, Sachi; Horii, Yuichi; Petrick, Gert; Gamo, Toshitaka

    2005-01-01

    Perfluorinated acids and their salts have emerged as an important class of global environmental contaminants. Biological monitoring surveys conducted using tissues of marine organisms reported the occurrence of perfluorooctanesulfonate (PFOS) and related perfluorinated compounds in biota from various seas and oceans, including the Arctic and the Antarctic Oceans. Occurrence of perfluorinated compounds in remote marine locations is of concern and indicates the need for studies to trace sources and pathways of these compounds to the oceans. Determination of sub-parts-per-trillion (ng/L) or parts-per-quadrillion (pg/L) concentrations of aqueous media has been impeded by relatively high background levels arising from procedural or instrumental blanks. Our research group has developed a reliable and highly sensitive analytical method by which to monitor perfluorinated compounds in oceanic waters. The method developed is capable of detecting PFOS, perfluorohexanesulfonate (PFHS), perfluorobutanesulfonate (PFBS), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), and perfluorooctanesulfonamide (PFOSA) at a few pg/L in oceanic waters. The method was applied to seawater samples collected during several international research cruises undertaken during 2002-2004 in the central to eastern Pacific Ocean (19 locations), South China Sea and Sulu Seas (five), north and mid Atlantic Ocean (12), and the Labrador Sea (20). An additional 50 samples of coastal seawater from several Asian countries (Japan, China, Korea) were analyzed. PFOA was found at levels ranging from several thousands of pg/L in water samples collected from coastal areas in Japan to a few tens of pg/L in the central Pacific Ocean. PFOA was the major contaminant detected in oceanic waters, followed by PFOS. Further studies are being conducted to elucidate the distribution and fate of perfluorinated acids in oceans.

  4. Triphenylsilane-fused Porphyrins.

    PubMed

    Kato, Kenichi; Kim, Jun Oh; Yorimitsu, Hideki; Kim, Dongho; Osuka, Atsuhiro

    2016-06-01

    A reaction sequence of 2-(diphenylsilyl)phenylation by Negishi coupling and intramolecular sila-Friedel-Crafts reaction has been explored for the synthesis of mono-triphenylsilane-fused porphyrins 5 M and 6 M (M= Ni, Zn) and bis-triphenylsilane-fused porphyrins 7 M and 8 Ni. A triply linked triphenylsilane-fused Ni(II) porphyrin, 13 Ni, was synthesized in a stepwise manner involving the above reaction sequence and a final Pd-catalyzed C-H activating arylative cyclization. The silicon atom in 13 Ni takes a distorted planarized structure with an almost perpendicular Si-phenyl group, causing an electronic effect due to effective σ*-π* interaction. PMID:27124659

  5. Perfluorinated compounds in river water, river sediment, market fish, and wildlife samples from Japan.

    PubMed

    Senthilkumar, Kurunthachalam; Ohi, Etsumasa; Sajwan, Kenneth; Takasuga, Takumi; Kannan, Kurunthachalam

    2007-10-01

    Perfluorinated organic compounds (PFCs) such as PFOS, PFOA, PFBS, PFHxS, PFOSA and PFDoA were determined in river water, river sediment, liver of market fish and liver of wildlife samples from Japan. Concentrations of PFOA and PFOS in water samples were 7.9-110 and <5.2-10 ng/L. Only PFOA were detected in sediment from Kyoto river at 1.3-3.9 ng/g dry wt. Among fish, only jack mackerel showed PFOA and PFOS at 10 and 1.6 ng/g wet wt. Wildlife liver contained PFOSA, PFOS, PFDoA, PFOA and PFHxS in the range of 0.31-362, 0.15-238, <0.03-28, >0.07-7.3 and <0.03-1.5, respectively, on ng/g wet wt. Cormorants showed maximum accumulation followed by eagle, raccoon dog and large-billed crow.

  6. OLED panel with fuses

    DOEpatents

    Levermore, Levermore; Pang, Huiqing; Rajan, Kamala

    2014-09-16

    Embodiments may provide a first device that may comprise a substrate, a plurality of conductive bus lines disposed over the substrate, and a plurality of OLED circuit elements disposed on the substrate, where each of the OLED circuit elements comprises one and only one pixel electrically connected in series with a fuse. Each pixel may further comprise a first electrode, a second electrode, and an organic electroluminescent (EL) material disposed between the first and the second electrodes. The fuse of each of the plurality of OLED circuit elements may electrically connect each of the OLED circuit elements to at least one of the plurality of bus lines. Each of the plurality of bus lines may be electrically connected to a plurality of OLED circuit elements that are commonly addressable and at least two of the bus lines may be separately addressable.

  7. Concentrations and trends of Perfluorinated chemicals in potential indoor sources from 2007 through 2011 in the US

    EPA Science Inventory

    Certain perfluorinated chemicals in consumer products have been associated with developmental toxicity and other adverse health effects. Temporal trends in the concentrations of selected perfluorinated chemicals (PFCs), including perfluorooctanoic acid (PFOA) and other perfluoroc...

  8. Removal of Perfluorinated Grease Components from NTO Oxidizer

    NASA Technical Reports Server (NTRS)

    McClure, Mark B.; Greene, Ben; Johnson, Harry T.

    2004-01-01

    Perfluorinated greases are typically used as a thread lubricant in the assembly of non-welded nitrogen tetroxide (NTO) oxidizer systems. These greases, typically a perfluoroalkylether, with suspended polytetrafluoroethylene (PTFE) micro-powder, have attractive lubricating properties toward threaded components and are relatively chemically inert toward NTO oxidizers. A major drawback, however, is that perfluoroalkylether greases are soluble or dispersible in NTO oxidizers and can contaminate the propellant. The result is propellant that fails the non-volatile residue (NVR) specification analyses and that may have negative effects on test hardware performance and lifetime. Consequently, removal of the grease contaminants from NTO may be highly desirable. Methods for the removal of perfluorinated grease components from NTO oxidizers including distillation, adsorption, filtration, and adjustment of temperature are investigated and reported in this work. Solubility or dispersibility data for the perfluoroalkylether oil (Krytox(tm)143 AC) component of a perfluorinated grease (Krytox 240 AC) and for Krytox 240 AC in NTO were determined and are reported.

  9. Method for fusing bone

    DOEpatents

    Mourant, Judith R.; Anderson, Gerhard D.; Bigio, Irving J.; Johnson, Tamara M.

    1996-01-01

    Method for fusing bone. The present invention is a method for joining hard tissue which includes chemically removing the mineral matrix from a thin layer of the surfaces to be joined, placing the two bones together, and heating the joint using electromagnetic radiation. The goal of the method is not to produce a full-strength weld of, for example, a cortical bone of the tibia, but rather to produce a weld of sufficient strength to hold the bone halves in registration while either external fixative devices are applied to stabilize the bone segments, or normal healing processes restore full strength to the tibia.

  10. Self-healing fuse development.

    NASA Technical Reports Server (NTRS)

    Jones, N. D.

    1972-01-01

    The self-healing fuse is a very fast acting current overload protective device which opens and recloses in a few milliseconds. The fuse confines a mercury column in an insulated channel and returns the mercury to the channel after firing. Ratings 5 to 50 A at 600 peak volts are possible with a life of hundreds of cycles. Compared to conventional fuses, much less fault current energy fires the fuse by heating the mercury to boiling temperature. Next an arc discharge develops while explosive forces expel the liquid mercury from the channel. Then the high impedance arc either extinguishes immediately, or operates for a few milliseconds, until a switch opens the circuit.

  11. Coupling losses in perfluorinated multi-core polymer optical fibers.

    PubMed

    Durana, Gaizka; Aldabaldetreku, Gotzon; Zubia, Joseba; Arrue, Jon; Tanaka, Chikafumi

    2008-05-26

    The aim of the present paper is to provide a comprehensive analysis of coupling losses in perfluorinated (PF) multi-core polymer optical fibers (MC-POFs), which consist of groups of 127 graded-index cores. In our analysis we take into account geometrical, longitudinal, transverse, and angular misalignments. We perform several experimental measurements and computer simulations in order to calculate the coupling losses for a PF MC-POF prototype. Based on these results, we propose several hints of practical interest to the manufacturer which would allow an appropriate connector design in order to handle conveniently the coupling losses incurred when connectorizing two PF MC-POFs. PMID:18545503

  12. Matrix isolation and spectroscopic characterization of perfluorinated ortho- and meta-benzyne.

    PubMed

    Wenk, H H; Sander, W

    2001-05-01

    The matrix isolation and spectroscopic characterization of two C6F4 isomers, the perfluorinated o-benzyne 4 and the m-benzyne 5, is reported. UV photolysis of tetrafluorophthalic anhydride 6 in solid argon at 10 K results in the formation of CO, CO2, and 1,2-didehydro-3,4,5,6-tetrafluorobenzene (4) in a clean reaction. On subsequent 350 nm irradiation 4 is carbonylated to give the cyclopropenone 7. 1,3-Didehydro-2,4,5,6-tetrafluorobenzene (5) was synthesized by UV irradiation of 1,3-diiodo-2,4,5,6-tetrafluorobenzene (8) via 2,3,4,6-tetrafluoro-5-iodophenylradical 9. Photolysis of 8 in solid neon at 3 K produces good yields of both radical 9 and benzyne 5, while in argon at 10 K no reaction is observed. Thus, the photochemistry in neon at extremely low temperature markedly differs from the photochemistry in argon. The formation of 5 from 8 via 9 is reversible, and annealing the neon matrix at 8 K leads back to the starting material 8. The benzynes 4 and 5 and the radical 9 were characterized by comparison of their matrix IR spectra with density functional theory (DFT) calculations.

  13. Neurobehavioral teratogenicity of perfluorinated alkyls in an avian model.

    PubMed

    Pinkas, Adi; Slotkin, Theodore A; Brick-Turin, Yael; Van der Zee, Eddy A; Yanai, Joseph

    2010-01-01

    Perfluorinated alkyls are widely-used agents that accumulate in ecosystems and organisms because of their slow rate of degradation. There is increasing concern that these agents may be developmental neurotoxicants and the present study was designed to develop an avian model for the neurobehavioral teratogenicity of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Fertilized chicken eggs were injected with 5 or 10mg/kg of either compound on incubation day 0. On the day of hatching, imprinting behavior was impaired by both compounds. We then explored underlying mechanisms involving the targeting of protein kinase C (PKC) isoforms (alpha, beta, gamma) in the intermedial part of the hyperstriatum ventrale, the region most closely associated with imprinting. With PFOA exposure, cytosolic PKC concentrations were significantly elevated for all three isoforms; despite the overall increase in PKC expression, membrane-associated PKC was unaffected, indicating a defect in PKC translocation. In contrast, PFOS exposure evoked a significant decrease in cytosolic PKC, primarily for the beta and gamma isoforms, but again without a corresponding change in membrane-associated enzyme; this likely partial, compensatory increases in translocation to offset the net PKC deficiency. Our studies indicate that perfluorinated alkyls are indeed developmental neurotoxicants that affect posthatch cognitive performance but that the underlying synaptic mechanisms may differ substantially among the various members of this class of compounds, setting the stage for disparate outcomes later in life.

  14. Neurobehavioral Teratogenicity of Perfluorinated Alkyls in an Avian Model

    PubMed Central

    Pinkas, Adi; Slotkin, Theodore A.; Brick-Turin, Yael; Van der Zee, Eddy A.; Yanai, Joseph

    2010-01-01

    Perfluorinated alkyls are widely-used agents that accumulate in ecosystems and organisms because of their slow rate of degradation. There is increasing concern that these agents may be developmental neurotoxicants and the present study was designed to develop an avian model for the neurobehavioral teratogenicity of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Fertilized chicken eggs were injected with 5 or 10 mg/kg of either compound on incubation day 0. On the day of hatching, imprinting behavior was impaired by both compounds. We then explored underlying mechanisms involving the targeting of protein kinase C (PKC) isoforms (α, β, γ) in the intermedial part of the hyperstriatum ventrale, the region most closely associated with imprinting. With PFOA exposure, cytosolic PKC concentrations were significantly elevated for all three isoforms; despite the overall increase in PKC expression, membrane-associated PKC was unaffected, indicating a defect in PKC translocation. In contrast, PFOS exposure evoked a significant decrease in cytosolic PKC, primarily for the β and γ isoforms, but again without a corresponding change in membrane-associated enzyme; this likely partial, compensatory increases in translocation to offset the net PKC deficiency. Our studies indicate that perfluorinated alkyls are indeed developmental neurotoxicants that affect posthatch cognitive performance but that the underlying synaptic mechanisms may differ substantially among the various members of this class of compounds, setting the stage for disparate outcomes later in life. PMID:19945530

  15. Operations with the FUSE observatory

    NASA Astrophysics Data System (ADS)

    Blair, William P.; Kruk, Jeffrey W.; Moos, Henry W.; Oegerle, William R.

    2003-02-01

    The Far Ultraviolet Spectroscopic Explorer satellite (FUSE) is a NASA Origins mission launched on 1999 June 24 and operated from the Johns Hopkins University Homewood campus in Baltimore, MD. FUSE consists of four aligned telescopes feeding twin far-ultraviolet spectrographs that achieve a spectral resolution of R=20,000 over the 905-1187 Å spectral region. This makes FUSE complementary to the Hubble Space Telescope and of broad general interest to the astronomical community. FUSE is operated as a general-purpose observatory with proposals evaluated and selected by NASA. The FUSE mission concept evolved dramatically over time. The version of FUSE that was built and flown was born out of the "faster, better, cheaper" era, which drove not only the mission development but also plans for operations. Fixed price contracts, a commercial spacecraft, and operations in the University environment were all parts of the low cost strategy. The satellite performs most functions autonomously, with ground contacts limited typically to seven 12-minute contacts per day through a dedicated ground station. All support functions are managed by a staff of 40 scientists and engineers located at Johns Hopkins. In this configuration, we have been able to achieve close to 30% average on-target science efficiency. In short, FUSE is a successful example of the "faster, better, cheaper" philosophy.

  16. DETERMINATION OF PERFLUORINATED CHEMICALS (PFCS) IN SOILS, SEDIMENT AND OTHER MATRICES

    EPA Science Inventory

    Soils that receive land application of treated wastewater from carpet manufacturing plants were sampled for perfluorooctanoic acid (PFOA) and other perfluorinated chemicals (PFCs) that are potential degradation products of fluorotelomer-based polymers (FBPs). Soils from other pot...

  17. Geographical Distribution of Perfluorinated Compounds in Fish from Minnesota Lakes and Rivers

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have been used extensively in consumer and industrial products and are not found in environmental and biological samples around the world. Recent research suggests that fish consumption may be an important human exposure pathway to perfluorooctane...

  18. Pilot Scale Application of a Method for the Analysis of Perfluorinated Compounds in Surface Soils

    EPA Science Inventory

    A growing number of studies now indicate that perfluorinated compounds (PFCs) are globally distributed in the environment. Their widespread distribution and presence in remote locations has led to questions about the importance of atmospheric and oceanic transport. Describing the...

  19. Factors Affecting the Distribution of Perfluorinated Compounds in Sediments from Lake Shihwa, Korea

    EPA Science Inventory

    Perfluorinated compounds (PFCs) are ubiquitously distributed in various environmental media including water, soil, sediment, and biota. PFCs have also been shown to biomagnify in both aquatic and terrestrial environments. Lake Shihwa is an artificial saltwater lake, located on ...

  20. Multi-Platform Metabolomic Analyses of Rat Urine Following Exposure to Perfluorinated Chemicals (PFCs)

    EPA Science Inventory

    Perfluorinated chemicals (PFCs), namely perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), represent an emerging class of persistent and bioaccumulative compounds. Global occurrence of these fluorochemicals, coupled with probable human exposure, has prompted inv...

  1. Preliminary assessment of developmental toxicity of Perfluorinated Phosphonic Acid in mice

    EPA Science Inventory

    Perfluorinated phosphonic acids (PFPAs) are a third member of the perfluoroalkyl acid (PFAA) family, and are structurally similar to the perfluoroalkyl sulfonates and perfluoroalkyl carboxylates. These emerging chemicals have recently been detected in the environment, particularl...

  2. AN INTERLABORATORY STUDY OF PERFLUORINATED ALKYL COMPOUND LEVELS IN HUMAN PLASMA

    EPA Science Inventory

    The present study was designed to investigate intra- and interlaboratory variability in results from six laboratories experienced in the analysis of perfluorinated alkyl compounds in blood matrices and that use stringent procedures to control and assure accuracy and precision. Ea...

  3. Effects of Perfluorinated Phosphonic Acid Exposure during pregnancy in the mouse

    EPA Science Inventory

    Perfluorinated phosphonic acids (PFPAs) are a member of the perfluoroalkyl acid (PFAA) family, and are structurally similar to the perfluoroalkyl sulfonates and perfluoroalkyl carboxylates. These chemicals have recently been detected in the environment, particularly in surface wa...

  4. Perfluorinated Compounds in Fish from U.S. Urban Rivers and the Great Lakes

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have recently received scientific and regulatory attention due to their broad environmental distribution, persistence, bioaccumulative potential, and toxicity. Some studies suggest that the consumption of fish from contaminated waters may be a maj...

  5. Determination of Ten Perfluorinated Compounds in Bluegill Sunfish (Lepomis macrochirus) Fillets

    EPA Science Inventory

    Limited information is known about the environmental distributions of the perfluorinated compounds (PFCs) such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), in part due to a lack of well characterized analytical methods that can be used to accurately mea...

  6. Distributed perfluorinated POF strain sensor using OTDR and OFDR techniques

    NASA Astrophysics Data System (ADS)

    Liehr, Sascha; Wendt, Mario; Krebber, Katerina

    2009-10-01

    This paper presents the latest advances in distributed strain sensing using perfluorinated (PF) polymer optical fibers (POF). Compared to previously introduced PMMA POF strain sensors, PF POF have the advantage of lower loss and therefore extended measurement length of more than 500 m at increased spatial resolution of 10 cm. It is shown that PF POF can measure strain distributed up to 100 %. The characteristic backscatter signature of this fiber type provides additional evaluation possibilities. We show that, by applying a cross-correlation algorithm to the backscatter signal, the distributed length change can be measured along the fiber. We also present, to our knowledge for the first time, incoherent Optical Frequency Domain Reflectometry (OFDR) in POF to measure distributed reflections and loss along the fiber. The OFDR technique proves superior to existing OTDR techniques in measurement speed, resolution and potential instrument costs.

  7. New insights into perfluorinated adsorbents for analytical and bioanalytical applications.

    PubMed

    Marchetti, Nicola; Guzzinati, Roberta; Catani, Martina; Massi, Alessandro; Pasti, Luisa; Cavazzini, Alberto

    2015-01-01

    Perfluorinated (F-) adsorbents are generally prepared by bonding perfluoro-functionalized silanes to silica gels. They have been employed for a long time essentially as media for solid-phase extraction of F-molecules or F-tagged molecules in organic chemistry and heterogeneous catalysis. More recently, this approach has been extended to proteomics and metabolomics. Owing to their unique physicochemical properties, namely fluorophilicity and proteinophilicity, and a better understanding of some fundamental aspects of their behavior, new applications of F-adsorbents in the field of environmental science and bio-affinity studies can be envisaged. In this article, we revisit the most important features of F-adsorbents by focusing, in particular, on some basic information that has been recently obtained through (nonlinear) chromatographic studies. Finally, we try to envisage new applications and possibilities that F-adsorbents will allow in the near future. PMID:25358910

  8. A new and efficient procedure for the synthesis of hexahydropyrimidine-fused 1,4-naphthoquinones

    PubMed Central

    Reis, Marcelo Isidoro P; Campos, Vinícius R; Resende, Jackson A L C; Silva, Fernando C

    2015-01-01

    Summary A new and efficient method for the synthesis of hexahydropyrimidine-fused 1,4-naphthoquinones in one step with high yields from the reaction of lawsone with 1,3,5-triazinanes was developed. PMID:26425181

  9. 1,3-Butadiene

    Integrated Risk Information System (IRIS)

    1,3 - Butadiene ; CASRN 106 - 99 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic E

  10. 1,3-Dichloropropene

    Integrated Risk Information System (IRIS)

    1,3 - Dichloropropene ( DCP ) ; CASRN 542 - 75 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Non

  11. 1,3-Dichlorobenzene

    Integrated Risk Information System (IRIS)

    1,3 - Dichlorobenzene ; CASRN 541 - 73 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinog

  12. 30 CFR 57.6502 - Safety fuse.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Safety fuse. 57.6502 Section 57.6502 Mineral...-Surface and Underground § 57.6502 Safety fuse. (a) The burning rate of each spool of safety fuse to be used shall be measured, posted in locations which will be conspicuous to safety fuse users, and...

  13. 30 CFR 56.6502 - Safety fuse.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Safety fuse. 56.6502 Section 56.6502 Mineral....6502 Safety fuse. (a) The burning rate of each spool of safety fuse to be used shall be measured, posted in locations which will be conspicuous to safety fuse users, and brought to the attention of...

  14. Stepwise π-extension of meso-alkylidenyl porphyrins through sequential 1,3-dipolar cycloaddition and redox reactions.

    PubMed

    Park, Dowoo; Jeong, Seung Doo; Ishida, Masatoshi; Lee, Chang-Hee

    2014-08-25

    Several regioselectively π-extended, pyrrole fused porphyrinoids have been synthesized by the 1,3-dipolar cycloaddition of meso-alkylidene-(benzi)porphyrins. Pd(II) complexes gave oxidation resistant, bis-pyrrole fused adducts. The repeated 1,3-dipolar cycloaddition followed by oxidation-reduction of pentaphyrin analogs afforded π-extended porphyrin analogs.

  15. TTFs nonsymmetrically fused with alkylthiophenic moieties

    PubMed Central

    Silva, Rafaela A L; Vieira, Bruno J C; Andrade, Marta M; Santos, Isabel C; Rabaça, Sandra

    2015-01-01

    Summary Two new dithiolene ligand precursors, containing fused TTF and alkyl thiophenic moieties 3,3'-{[2-(5-(tert-butyl)thieno[2,3-d][1,3]dithiol-2-ylidene)-1,3-dithiole-4,5-diyl]bis[sulfanediyl]}dipropanenitrile (α-tbtdt, 1), and 3,3'-{[2-(5-methylthieno[2,3-d][1,3]dithiol-2-ylidene)-1,3-dithiole-4,5-diyl]bis[sulfanediyl]}dipropanenitrile (α-mtdt, 2), were synthesized and characterized. The electrochemical properties of these electronic donors were studied by cyclic voltammetry (CV) in dichloromethane. Both compounds show two quasi-reversible oxidation processes, versus Ag/AgCl, typical of TTF donors at E 1 1/2 = 279 V and E 2 1/2 = 680 V for 1 and E 1 1/2 = 304 V and E 2 1/2 = 716 V in the case of 2. The single-crystal X-ray structure of 1 and of a charge transfer salt of 2, (α-mtdt)[Au(mnt)2] (3), are reported. PMID:26124865

  16. 16 CFR 1507.3 - Fuses.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Fuses. 1507.3 Section 1507.3 Commercial... § 1507.3 Fuses. (a) Fireworks devices that require a fuse shall: (1) Utilize only a fuse that has been... composition are exempted from § 1507.3(a)(1). (2) Utilize only a fuse which will burn at least 3 seconds...

  17. Perfluorinated carboxylic acids discharged from the Yodo River Basin, Japan.

    PubMed

    Niisoe, Tamon; Senevirathna, S T M L D; Harada, Kouji H; Fujii, Yukiko; Hitomi, Toshiaki; Kobayashi, Hatasu; Yan, Junxia; Zhao, Can; Oshima, Masayo; Koizumi, Akio

    2015-11-01

    We investigated perfluorinated carboxylic acids (PFCAs) with 7-14 carbon atoms (C7-C14) in the Yodo River system in 2013. C7-C11 were detected at most sampling sites. The range and median of total PFCAs (ΣPFCAs) concentrations were 1.0-89.7 and 11.2 ng L(-1), respectively. The dominant component was C8 (average for all samples=53.3±8.8%), followed by C7 (19.2±6.7%) and C9 (17.6±7.1%). The levels of C8 were confirmed to decrease greatly over the last 10 years. We assessed the fluxes in C7-C11 discharged from the basin based on the concentrations in river water and river flow rate. The flux of discharged ΣPFCAs was 237.0 g d(-1) at the most downriver point of the assessment areas. Considering the variability in flow rate due to precipitation, the annual ΣPFCAs flux was estimated to be 86.5-173.4 kg y(-1). Identification and quantification of PFCAs sources is difficult because the strength of the sources changes with time, and available information is quite limited. Further monitoring and investigation are necessary to understand sources of PFCAs, as well as their potential for human exposure.

  18. [Residue Characteristics of Perfluorinated Compounds in the Atmosphere of Shenzhen].

    PubMed

    He, Peng-fei; Zhang, Hong; Li, Jing; He, Long; Luo, Ji; Liu, Guo-qing; Shen, Jin-can; Yang, Bo; Cui, Xiao-yu

    2016-04-15

    In order to explore the residual characteristics of perfluorinated compounds (PFCs) in the atmosphere of Shenzhen, passive air samplers consisting of polyurethane foam (PUF) disks impregnated with XAD-4 power were deployed at 12 sites in Shenzhen from November 2014 to February 2015. Seven volatile and fifteen ionic PFCs were analyzed. The results indicated that ΣPFCs concentration ranged from 23.7 pg x m(-3) to 157 pg x m(-3) (mean: 79.0 pg x m(-3)), dominated by volatile PFCs, with 8:2 FTOITI, 6:2 FTOH, PFPeA, PFOA being the dominant compounds. The spatial distribution of volatile and ionic PFCs concentrations was the same, displaying the characteristic of "the northwest being higher than the southeast ". Furthermore, the concentrations of 6:2 FTOHs, 8:2 FTOHs, PFPeA, PFHxA and PFOA had positive correlations with PM2.5 and PM10 (P < 0.05, P < 0.01) and were more positively correlated with the levels of PM10 than those of PM2.5.

  19. [Residue Characteristics of Perfluorinated Compounds in the Atmosphere of Shenzhen].

    PubMed

    He, Peng-fei; Zhang, Hong; Li, Jing; He, Long; Luo, Ji; Liu, Guo-qing; Shen, Jin-can; Yang, Bo; Cui, Xiao-yu

    2016-04-15

    In order to explore the residual characteristics of perfluorinated compounds (PFCs) in the atmosphere of Shenzhen, passive air samplers consisting of polyurethane foam (PUF) disks impregnated with XAD-4 power were deployed at 12 sites in Shenzhen from November 2014 to February 2015. Seven volatile and fifteen ionic PFCs were analyzed. The results indicated that ΣPFCs concentration ranged from 23.7 pg x m(-3) to 157 pg x m(-3) (mean: 79.0 pg x m(-3)), dominated by volatile PFCs, with 8:2 FTOITI, 6:2 FTOH, PFPeA, PFOA being the dominant compounds. The spatial distribution of volatile and ionic PFCs concentrations was the same, displaying the characteristic of "the northwest being higher than the southeast ". Furthermore, the concentrations of 6:2 FTOHs, 8:2 FTOHs, PFPeA, PFHxA and PFOA had positive correlations with PM2.5 and PM10 (P < 0.05, P < 0.01) and were more positively correlated with the levels of PM10 than those of PM2.5. PMID:27548942

  20. Fluorotelomer acids are more toxic than perfluorinated acids.

    PubMed

    Phillips, Michelle M MacDonald; Dinglasan-Panlilio, Mary Joyce A; Mabury, Scott A; Solomon, Keith R; Sibley, Paul K

    2007-10-15

    Saturated and unsaturated fluorotelomer carboxylic acids have been identified as intermediates in the degradation of fluorotelomer alcohols to perfluorinated carboxylic acids (PFCAs). Although surface waters are the likely environmental sink for telomer acids, no fate or toxicity data exist for this matrix. We assessed the acute toxicity of the 4:2, 6:2, 8:2, and 10:2 saturated (FTCA) and unsaturated (FTUCA) fluorotelomer carboxylic acids to Daphnia magna, Chironomus tentans, and Lemna gibba. In general, toxicity increased with increasing fluorocarbon (FC) chain length, particularly for telomer acids of > or =8 FCs. In addition, the FTCAs were generally more toxic than the corresponding FTUCAs. Acute EC50s ranged from 0.025 mg/L (0.04 micromol/L) for D. magna (10:2 FTCA, immobility) to 63 mg/L (167 micromol/L) for C. tentans (6:2 FTCA, growth). While chain-length trends observed in the current study agree with those previously reported for PFCAs, the toxicity thresholds generated here are up to 10,000 times smaller. Our data provide the first evidence that PFCA precursors are more toxic than the PFCAs themselves. PMID:17993163

  1. Exposure to perfluorinated compounds: in vitro study on thyroid cells.

    PubMed

    Coperchini, Francesca; Pignatti, Patrizia; Lacerenza, Serena; Negri, Sara; Sideri, Riccardo; Testoni, Claudia; de Martinis, Luca; Cottica, Danilo; Magri, Flavia; Imbriani, Marcello; Rotondi, Mario; Chiovato, Luca

    2015-02-01

    Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are widely used perfluorinated chemicals (PFCs). Previous studies detected PFOA and PFOS in human tissues including the thyroid gland. There are no studies on the in vitro effects of PFOA and PFOS on thyroid cells. Our study was aimed at evaluating the effect of the in vitro exposure to PFOA and PFOS on thyroid cell proliferation and viability. These objectives were investigated using Fisher rat thyroid line-5 (FRTL-5) cells. FRTL-5 cells cultured in the presence of PFOA and PFOS at concentrations up to 10(4) nM do not display changes in their viability and proliferation rate, while at a concentration of 10(5) nM of either PFCs, a significant inhibition of cell proliferation, mainly due to increased cell death, was found. PFOA and PFOS were detected in FRTL-5 cell pellets after 72 h of incubation with PFCs but not in control cultures. When FRTL-5 were incubated with PFCs then washed in PBS and re-cultured for 72 h without PFCs in the medium, no detectable concentrations of PFOA and PFOS were measured in the cell pellet. This indicates that PFOA and PFOS enter thyroid cells by a gradient-based passive diffusion mechanism. Future studies are required to evaluate the potential toxic effect resulting from prolonged in vivo exposure to even lower concentrations of PFCs. PMID:25182428

  2. Gastrointestinal Elimination of Perfluorinated Compounds Using Cholestyramine and Chlorella pyrenoidosa

    PubMed Central

    Genuis, Stephen J.; Curtis, Luke; Birkholz, Detlef

    2013-01-01

    Background. While perfluorinated compounds (PFCs) are a family of commonly used synthetic compounds with many applications, some PFCs remain persistent within the human body due, in part, to enterohepatic recirculation and renal tubular reabsorption. With increasing recognition of potential harm to human health associated with PFC bioaccumulation, interventions to facilitate elimination of these toxicants are welcome in order to potentially preclude or overcome illness. Minimal research has been undertaken thus far on methods to accelerate human clearance of PFCs. Methods. To test for possible oral treatments to hasten PFC elimination, a group of individuals with elevated PFC levels was treated with cholestyramine (CSM) and, after a break, was subsequently treated with Chlorella pyrenoidosa (CP). Stool samples were collected from all participants (i) prior to any treatment, (ii) during treatment with CSM, and (iii) during treatment with CP. Results. With CSM treatment, significant levels of three distinct PFCs were found in all stools, while levels were mostly undetectable prior to treatment. Following treatment with oral CP, undetectable or very low levels of all PFCs were noted in each sample tested. Conclusion. CSM appears to facilitate elimination of some common PFCs and may have some role in the clinical management of patients with accrued PFCs. PMID:24106616

  3. Effects of perfluorinated amphiphiles on backward swimming in Paramecium caudatum

    SciTech Connect

    Matsubara, Eriko; Harada, Kouji; Inoue, Kayoko; Koizumi, Akio . E-mail: koizumi@pbh.med.kyoto-u.ac.jp

    2006-01-13

    PFOS and PFOA are ubiquitous contaminants in the environment. We investigated the effects of fluorochemicals on calcium currents in Paramecium caudatum using its behavioral changes. Negatively charged amphiphiles prolonged backward swimming (BWS) of Paramecium. PFOS significantly prolonged BWS, while PFOA was less potent (EC{sub 5}: 29.8 {+-} 4.1 and 424.1 {+-} 124.0 {mu}M, respectively). The BWS prolongation was blocked by cadmium, indicating that the cellular calcium conductance had been modified. The positively charged amphiphile FOSAPrTMA shortened BWS (EC{sub 5}: 19.1 {+-} 17.3). Nonionic amphiphiles did not affect BWS. The longer-chain perfluorinated carboxylates PFNA and PFDA were more potent than PFOA (EC{sub 5}: 98.7 {+-} 20.1 and 60.4 {+-} 10.1 {mu}M, respectively). However, 1,8-perfluorooctanedioic acid and 1,10-perfluorodecanedioic acid did not prolong BWS. The critical micelle concentration (CMC) and BWS prolongation for negatively charged amphiphiles showed a clear correlation (r {sup 2} = 0.8008, p < 0.001). In summary, several perfluorochemicals and PFOS and PFOA had similar effects in Paramecium, while chain length, CMC, and electric charge were major determinants of BWS duration.

  4. Effects of gamma radiation on perfluorinated polymer optical fibers

    NASA Astrophysics Data System (ADS)

    Stajanca, Pavol; Mihai, Laura; Sporea, Dan; Neguţ, Daniel; Sturm, Heinz; Schukar, Marcus; Krebber, Katerina

    2016-08-01

    The paper presents the first complex study of gamma radiation effects on a low-loss perfluorinated polymer optical fiber (PF-POF) based on Cytop® polymer. Influence of gamma radiation on fiber's optical, mechanical and climatic performance is investigated. The radiation-induced attenuation (RIA) in the visible and near-infrared region (0.4 μm-1.7 μm) is measured and its origins are discussed. Besides attenuation increase, radiation is also shown to decrease the thermal degradation stability of the fiber and to increase its susceptibility to water. With regard to complex fiber transmission performance upon irradiation, the optimal operation wavelength region of PF-POF-based systems intended for use in radiation environments is determined to be around 1.1 μm. On the other hand, the investigated fiber holds potential for low-cost RIA-based optical fiber dosimetry applications with sensitivity as high as 260 dBm-1/kGy in the visible region.

  5. Solubilization of polycyclic aromatic hydrocarbons by perfluorinated surfactant micelles.

    PubMed

    An, Youn-Joo; Carraway, Elizabeth R; Schlautman, Mark A

    2002-01-01

    Due to their chemical and thermal stability, perfluorinated surfactants (PFSs) are promising materials for the development of novel environmental remediation applications. This stability also leads to the persistence of PFS in the environment; therefore, their properties and behavior should be well understood. This study focused on polycyclic aromatic hydrocarbon (PAH) and PFS interactions, particularly the solubilization of PAHs by PFS micelles. Naphthalene. phenanthrene, and pyrene were selected as representative PAHs and an anionic PFS, ammonium perfluorooctanoate (APFO) was used. Critical micelle concentration (CMC) values of APFO measured by surface tension, fluorescence probe, and solubility enhancement methods fell in the range of 20-30 mM at 22 +/- 1 degrees C. Apparent solubilities of molecular oxygen and PAHs in APFO micellar solutions depended linearly on the APFO concentration. Molar solubilization ratio (MSR) values were determined to be 9.50 x 10(-4), 4.17 x 10(-3), 2.31 x 10(-4), and 4.09 x 10(-5) and mole fraction micellar partition coefficient (Kmic) values were found to be 1.89 x 10(2), 9.50 x 10(2), 2.12 x 10(3), and 3.79 x 10(3) for oxygen, naphthalene, phenanthrene, and pyrene, respectively at 22 +/- 1 degrees C. log Kmic values for three PAHs were shown to be linearly correlated with the log values of octanol-water partition coefficients (log Kow).

  6. Annealed perfluorinated cation exchange polymers for corrosion resistant coatings

    SciTech Connect

    Kinlen, P.J.; Silverman, D.C. )

    1993-11-01

    Casting and annealing a perfluorinated cation exchange (Nafion) polymer onto aluminum or 316SS results in a system which inhibits pitting and crevice corrosion that normally occurs in the presence of chloride ions and dissolved oxygen. This inhibition is believed to results from the unique chloride ion rejection properties of the annealed Nafion coating. Under neutral and basic conditions (pH > 5), localized corrosion is suppressed. Potentiodynamic polarization scans of the annealed Nafion coated aluminum and 316SS positive to the potential of the bare electrode does not produce pits. Electrochemical impedance results show that corrosion is unchanged after the coated alloy has been polarized above the pitting potential. In addition, the electrochemical impedance results indicate that the electrical resistance of the coating is low, hardly increasing the uncompensated resistance above that found for the bare metal. Hence, the movement of water and positive ions through the coating is unhindered Long-term stability and long-term corrosion inhibition afforded by the polymer must still be assessed to determine the practical limits of applicability of this coating system.

  7. Online monitoring of gamma irradiated perfluorinated polymer optical fiber

    NASA Astrophysics Data System (ADS)

    Sporea, Dan; Mihai, Laura; Neguţ, Daniel; Stajanca, Pavol; Krebber, Katerina

    2016-04-01

    In this paper, we present the first results regarding the on-line monitoring of gamma-ray exposure effects on a commercial multi-mode perfluorinated polymer optical fiber (PF-POF), type GigaPOF-50SR from Chromis Fiberoptics. Our focus was to evaluate on-line the radiation induced attenuation (RIA) over a wide spectral range (320 nm - 1700 nm), in order to assess the fiber's radiation hardness and its possible use in radiation detection. An Ocean Optics QE65000 high sensitivity spectrometer and a StellarNet near-IR spectrometer were used to cover the spectral ranges 200 nm - 1μm and 900 nm - 1.6 μm, respectively. Electron paramagnetic resonance was used to monitor the recovery of the irradiation induced centers at room temperature. The study indicated that the optical fiber can be used as radiation monitor at low dose rates by measuring the attenuation in the UV, while higher dose rates irradiation can be observed by RIA monitoring at specific wavelengths in the visible spectral range.

  8. Electrolytic production of neodymium without perfluorinated carbon compounds on the offgases

    DOEpatents

    Keller, Rudolf; Larimer, Kirk T.

    1998-01-01

    A method of producing neodymium in an electrolytic cell without formation of perfluorinated carbon gases (PFCs), the method comprising the steps of providing an electrolyte in the electrolytic cell and providing an anode in an anode region of the electrolyte and providing a cathode in a cathode region of the electrolytic cell. Dissolving an oxygen-containing neodymium compound in the electrolyte in the anode region and maintaining a more intense electrolyte circulation in the anode region than in the cathode region. Passing an electrolytic current between said anode and said cathode and depositing neodymium metal at the cathode, preventing the formation of perfluorinated carbon gases by limiting anode over voltage.

  9. Ferrocene-fused derivatives of acenes, tropones and thiepins

    NASA Astrophysics Data System (ADS)

    Maharjan, Bidhya Laxmi

    bottomcontact, bottom-gate (BCBG) device architecture and the resulting performance parameters are described herein. Similarly, we are also interested in potential applications of metallocene-fused tropones and derivatives as organic electronic materials. Condensation of 1,2- diformylferrocene with acetone or 1,3-diphenylacetone in the presence of KOH resulted in the ferrocene-fused tropone (eta5-2,4-cyclopentadien-1-yl)[(1,2,3,3a,8a-eta)-1,6-dihydro- 6-oxo-1-azulenyl]iron (1, R = H, E = O) and its 5,7-diphenyl derivative (1, R = Ph, E = O) as previously reported by Tirouflet. The use of piperidine as base resulted in Michael addition of piperidine to one of the carbon-carbon double bonds of the tropones. Lawesson's reagent converted the ferrocene-fused tropones to either a thiotropone (1, R = H, E = S) or a detached 5,7-diphenylazulenethiol (2). Reaction of the ferrocene-fused thiotropone with hydroxylamine gave the corresponding oxime (1, R = H, E = NOH). Products were characterized by using spectroscopic methods and X-ray crystallography. Their electronic properties were studied by using cyclic voltammetry and UV-visible spectroscopy. The third project involved the two-fold aldol condensation of 1,2- diformylferrocene with dimethylthioglycolate S-oxide in the presence of freshly distilled triethylamine, which gave mono- and di-dehydrated products. Deoxygenation of the ferrocene-fused thiepin S-oxide with 2-chloro-1,3,2-benzodioxaphosphole in the presence of pyridine resulted in the corresponding thiepin. The ester groups of the thiepin and thiepin S-oxide were hydrolyzed under basic conditions to give carboxylic acids, which were converted into acid chlorides using oxalyl chloride. Attempts to decarboxylate the thiepin and thiepin S-oxide diacids resulted in decomposition.

  10. 16 CFR 1507.3 - Fuses.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES § 1507.3 Fuses. (a) Fireworks devices that require a fuse shall: (1) Utilize only a fuse that has been... it will support either the weight of the fireworks device plus 8 ounces of dead weight or double...

  11. 16 CFR 1507.3 - Fuses.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES § 1507.3 Fuses. (a) Fireworks devices that require a fuse shall: (1) Utilize only a fuse that has been... it will support either the weight of the fireworks device plus 8 ounces of dead weight or double...

  12. 16 CFR 1507.3 - Fuses.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES § 1507.3 Fuses. (a) Fireworks devices that require a fuse shall: (1) Utilize only a fuse that has been... it will support either the weight of the fireworks device plus 8 ounces of dead weight or double...

  13. 16 CFR 1507.3 - Fuses.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES § 1507.3 Fuses. (a) Fireworks devices that require a fuse shall: (1) Utilize only a fuse that has been... it will support either the weight of the fireworks device plus 8 ounces of dead weight or double...

  14. 30 CFR 28.2 - Approved fuses.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Approved fuses. 28.2 Section 28.2 Mineral... MINING PRODUCTS FUSES FOR USE WITH DIRECT CURRENT IN PROVIDING SHORT-CIRCUIT PROTECTION FOR TRAILING CABLES IN COAL MINES General Provisions § 28.2 Approved fuses. (a) On and after the effective date...

  15. Effects of perfluorinated compounds on development of zebrafish embryos.

    PubMed

    Zheng, Xin-Mei; Liu, Hong-Ling; Shi, Wei; Wei, Si; Giesy, John P; Yu, Hong-Xia

    2011-08-01

    Perfluorinated compounds (PFCs) have been widely used in industrial and consumer products and frequently detected in many environmental media. Potential reproductive effects of perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) have been reported in mice, rats and water birds. PFOS and PFOA were also confirmed developing toxicants towards zebrafish embryos; however, the reported effect concentrations were contradictory. Polyfluorinated alkylated phosphate ester surfactants (including FC807) are precursor of PFOS and PFOA; however, there is no published information about the effects of FC807 and PFNA on zebrafish embryos. Therefore, this study was conducted to determine the effects of these four PFCs on zebrafish embryos. Normal fertilized zebrafish embryos were selected to be exposed to several concentrations of PFOA, PFNA, PFOS or FC807 in 24-well cell culture plates. A digital camera was used to image morphological anomalies of embryos with a stereomicroscope. Embryos were observed through matching up to 96-h post-fertilization (hpf) and rates of survival and abnormalities recorded. PFCs caused lethality in a concentration-dependent manner with potential toxicity in the order of PFOS > FC807 > PFNA > PFOA based on 72-h LC(50). Forty-eight-hour post-fertilization pericardial edema and 72- or 96-hpf spine crooked malformation were all observed. PFOA, PFNA, PFOS and FC807 all caused structural abnormalities using early stages of development of zebrafish. The PFCs all retarded the development of zebrafish embryos. The toxicity of the PFCs was related to the length of the PFC chain and functional groups. PMID:22828880

  16. METHOD DEVELOPMENT FOR THE DETERMINATION OF PERFLUORINATED ORGANIC COMPOUNDS ( PFCS ) IN SURFACE WATER

    EPA Science Inventory

    The method for the determination of perfluorinated organic compounds (PFCs) in surface water has been developed and applied to natural water. The method shows an adequate sensitivity, precision and accuracy for ten kinds of target compounds. These PFCs were found in most samples...

  17. Perfluorinated nitrosopyrazolone-based erbium chelates: a new efficient solution processable NIR emitter.

    PubMed

    Beverina, Luca; Crippa, Maurizio; Sassi, Mauro; Monguzzi, Angelo; Meinardi, Francesco; Tubino, Riccardo; Pagani, Giorgio A

    2009-09-14

    We show the design and synthesis of new perfluorinated nitrosopyrazolone-based ligands and the original method employed for their complexation of erbium ions in the presence of the co-ligand perfluorotriphenylphosphine oxide; the resulting chelate is non-hygroscopic, solution processable and possesses a NIR emission with lifetimes as long as 16 micros.

  18. Serum concentrations of perfluorinated compounds (PFC) among selected populations of children and Adults in California

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have been widely used in industrial applications and consumer products. Their persistent nature and potential health impacts are of concern. Given the high cost of collecting serum samples, this study is to understand whether we can quantify PFC se...

  19. PERFLUORINATED COMPOUNDS IN THE CAPE FEAR DRAINAGE BASIN IN NORTH CAROLINA

    EPA Science Inventory

    Concern over perfluorinated organic compounds (PFCs), e.g., perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), is due to a number of recent studies which show that the PFCs are persistent, bioaccumulative, and toxic. Despite sustained interest in this topic, lit...

  20. 49 CFR 173.184 - Highway or rail fusee.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Highway or rail fusee. (a) A fusee is a device designed to burn at a controlled rate and to produce visual effects for signaling purposes. The composition of the fusee must be such that the fusee will not...

  1. 49 CFR 173.184 - Highway or rail fusee.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Highway or rail fusee. (a) A fusee is a device designed to burn at a controlled rate and to produce visual effects for signaling purposes. The composition of the fusee must be such that the fusee will not...

  2. Tricyclic flavonoids with 1,3-dithiolium substructure.

    PubMed

    Bahrin, Lucian G; Jones, Peter G; Hopf, Henning

    2012-01-01

    The synthesis of new 3-dithiocarbamic flavonoids has been accomplished by the reaction of the corresponding 2-hydroxyaryl dithiocarbamates with aminals. These flavonoids were obtained as a mixture of diastereoisomers, the anti isomer being the major one. The heterocyclization of these compounds provided novel tricyclic flavonoids bearing a 1,3-dithiolium-2-yl ring fused at the 3,4-carbon positions of the benzopyran moiety. PMID:23209535

  3. Perfluorinated compounds in seafood from coastal areas in China.

    PubMed

    Wu, Yongning; Wang, Yuxin; Li, Jingguang; Zhao, Yunfeng; Guo, Feifei; Liu, Jiaying; Cai, Zongwei

    2012-07-01

    Diet is an important source of perfluorinated compound (PFC) exposure and seafood is an important diet component for coastal populations. Therefore, it is necessary to monitor the concentrations of PFCs in seafood. In this study, we measured thirteen PFCs in 47 fatty fish and 45 shellfish samples collected from six coastal provinces in China (Liaoning, Shandong, Jiangsu, Zhejiang, Fujian, and Guangdong), using an ultra-performance liquid chromatography and tandem mass spectrometry (UPLC-MS/MS). Perfluorooctanesulfonate (PFOS) was the dominant PFC in fatty fish which accounted for 38% of total PFCs, whereas perfluoroctanoic acid (PFOA) was the predominant PFC in shellfish. Concentrations of PFOS were ranged from less than 1.4 to 1627 pg/g wet weight in fatty fish, with the highest concentration in red drum from Jiangsu. Concentrations of PFOA in shellfish ranged from less than 5.4 to 7543 pg/g wet weight, with the maximum concentration found in briny clam also from Jiangsu. Compared with other studies, the PFC levels in seafood collected from our studied areas are relatively low. The estimated dietary intakes (EDI, pg/kg body weight /day) of PFOA, PFOS and total PFCs for the reference man (63 kg body weight) were calculated by multiplying the mean concentrations (pg/g wet weight) of PFOA, PFOS and total PFCs in six coastal provinces with the daily consumption data (g/day) from the fourth Chinese total diet study carried out in 2007. The highest EDI of PFOS and PFOA were found to be 694 pg/kg body weight/day and 914 pg/kg body weight/day in Guangdong and Jiangsu, respectively. However, the highest EDI of total PFCs was found in Fujian at 2513 pg/kg body weight/day. The EDI from seafood is much lower than the tolerable daily intake (TDI) recommended by the European Food Safety Authority in 2008 indicating low health risk of PFC exposure via eating seafood among the coastal populations in China. PMID:21550116

  4. Determination of an Effective Perfluorinated Compounds (PFCs) Oxidation Method

    NASA Astrophysics Data System (ADS)

    Siriwardena, D. P.; Crimi, M.; Holsen, T.; Bellona, C.

    2014-12-01

    Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are a stable synthetic class of chemicals ubiquitously spread in environmental media (i.e. air, soil, biota, surface water and groundwater). The substances' strong polar carbon-fluorine bonds and their high thermal and chemical stability make them resistant to biological, chemical, and physical degradation. The purpose of this research is to identify the most effective oxidation method to treat perfluorinated compounds (PFCs) and their by-products that is suitable for in situ application. The laboratory oxidation study focuses on the more commonly detected and studied long-chain (C-8) PFAS; perfluorooctanoic acids (PFOA) and perfluorooctane sulfonic acid (PFOS). Existing research evaluating oxidizing treatment effectiveness on perfluoroalkyl sulfoinoic acids (PFSAs) is limited. A review of the literature and results from preliminary studies indicate that activated persulfate and catalyzed hydrogen peroxide propagation (CHP) reactions appear to be promising oxidants for PFOA. It has been demonstrated that the reactivity of superoxide in water increases in the presence of hydrogen peroxide (H2O2) and solids. Superoxide generated in CHP reactions degrades PFOA seemingly similar to superoxide-mediated destruction of the perhalogenated compounds.The goal of this study is to look at conditions that promote generation of superoxide and look at PFASs treatment effectiveness and byproduct generation. CHP reactions are conducted with varying amount of H2O2 and Fe(III) to determine the optimum conditions for PFC degradation. Results will be compared to those of another experiment using manganese dioxide as a CHP catalyst with varied H2O2 concentration to generate superoxide to degrade PFASs. Activated persulfate conditions to be compared include alkaline pH activation, heat activation, and dual oxidation (combined H2O2 and persulfate ). This presentation will focus on a comparison of oxidation effectiveness under the

  5. Application of WWTP Biosolids and Resulting Perfluorinated Compound Contamination of Surface and Well Water in Decatur, Alabama, USA

    EPA Science Inventory

    Perfluorinated chemicals (PFCs) such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been produced and used in a wide range of industrial and consumer products for many decades. Their resistance to degradation has led to their widespread distribution in...

  6. Perfluorinated Chemicals in Surface Waters and Sediments from Northwest Georgia, USA, and Their Bioaccumulation in Lumbriculus variegatus

    EPA Science Inventory

    Concentrations of perfluorinated chemicals (PFCs) were measured in surface waters and sediments from the Coosa River watershed in northwest Georgia, USA, to examine their distribution downstream of a suspected source. Samples from eight sites were analyzed using liquid chromatogr...

  7. Perfluorinated compounds in the environment and the blood of residents living near fluorochemical plants in Fuxin, China.

    PubMed

    Bao, Jia; Liu, Wei; Liu, Li; Jin, Yihe; Dai, Jiayin; Ran, Xiaorong; Zhang, Zhixu; Tsuda, Shuji

    2011-10-01

    A fluorochemical industrial park was built in 2004 in Fuxin, China, for the production of polytetrafluoroethylene (PTFE) and perfluorobutane sulfonate (PFBS). Yet little is known about the distribution of fluorochemicals in the environment and in people living in and around the park. In this study, environmental samples were collected from 22 sites in Fuxin to investigate the extent of perfluorinated compound (PFC) contamination in the environment around the park, and in drinking water from the public water supply system and groundwater in shallow aquifers from private wells near the park. Serum samples were also collected from nonoccupationally exposed residents living in Fuxin to determine the PFC load of local residents. As the dominant contaminant of eight target PFCs, the maximum concentrations of perfluorooctanoic acid (PFOA) in sediment and river water of the River Xi along the industrial park were 48 ng/g dry weight and 668 ng/L, respectively; the highest PFOA concentration in groundwater beneath the park was 524 ng/L; and the PFOA levels in drinking water from the public water supply system ranged between 1.3 and 2.7 ng/L. In human serum, PFOA had the geometric mean at 4.3 ng/mL, ranging from 0.02 to 93 ng/mL. This study serves to document what should be the beginning of a long-term surveillance effort to minimize potential exposure of residents living in Fuxin.

  8. FUSE observations of Luminous Blue Variables

    NASA Astrophysics Data System (ADS)

    Iping, Rosina C.; Sonneborn, George; Massa, Derck L.

    P Cyg, AG Car, HD 5980 and η Car were observed with the Far Ultraviolet Spectroscopic Explorer ( FUSE) satellite. FUSE covers the spectral range from 980 Å to 1187 Å at a resolution of 0.05 Å. In this paper we discuss the far-UV properties of these LBVs and explore their similarities and differences. The FUSE observations of P Cyg and AG Car, both spectral type B2pe, are very similar. The atmospheres of both η Car and HD 5980 appear to be somewhat hotter and have much higher ionization stages (Si IV, S IV, and P V) in the FUSE spectrum than P Cyg and AG Car. There is a very good agreement between the FUSE spectrum of P Cygni and the model atmosphere computed by John Hillier with his code CMFGEN. The FUSE spectrum of η Car, however, does not agree very well with existing model spectra.

  9. Integrated fuses for OLED lighting device

    DOEpatents

    Pschenitzka, Florian

    2007-07-10

    An embodiment of the present invention pertains to an electroluminescent lighting device for area illumination. The lighting device is fault tolerant due, in part, to the patterning of one or both of the electrodes into strips, and each of one or more of these strips has a fuse formed on it. The fuses are integrated on the substrate. By using the integrated fuses, the number of external contacts that are used is minimized. The fuse material is deposited using one of the deposition techniques that is used to deposit the thin layers of the electroluminescent lighting device.

  10. Internal fuse modules for solid tantalum capacitors

    NASA Technical Reports Server (NTRS)

    Dematos, H. V.

    1981-01-01

    Miniature fuse modules were designed for and incorporated into two styles of solid tantalum capacitors. One is an epoxy molded, radial leaded, high frequency decoupling capacitor; the other is an hermetically sealed device with axial lead wires. The fusible element for both devices consists of a fine bimetallic wire which reacts exothermically upon reaching a critical temperature and then disintegrates. The desirability of having fused devices is discussed and design constraints, in particular those which minimize inductance and series resistance while optimizing fuse actuation characteristics, are reviewed. Factors affecting the amount of energy required to actuate the fuse and reliability of acuation are identified.

  11. A 1,3-Dihydro-1,3-azaborine Debuts

    PubMed Central

    Xu, Senmiao; Zakharov, Lev N.

    2011-01-01

    We present the first synthesis and characterization of a 1,3-dihydro-1,3-azaborine, a long-sought BN isostere of benzene. 1,3-Dihydro-1,3-azaborine is a stable structural motif with considerable aromatic character as evidenced by structural analysis and its reaction chemistry. Single crystal X-ray analysis indicates bonding consistent with significant electron delocalization. 1,3-Dihydro-1,3-azaborines also undergo nucleophilic substitutions at boron and electrophilic aromatic substitution reactions. In view of the versatility and impact of aromatic compounds in the biomedical field and in materials science, the present study further expands the available chemical space of arenes via BN/CC isosterism. PMID:22091703

  12. (PRESENTED AT TSUKIJI, CHUO-KU, JAPAN) PERSISTENT PERFLUORINATED COMPOUNDS IN THE ENVIRONMENT: A BRIEF INTRODUCTION TO THIS IMPORTANT NEW CLASS OF POLLUTANTS

    EPA Science Inventory

    PowerPoint presentation summarizing method development research involving the persistent perfluorinated organic compounds. Review of data indicating widespread distribution of these materials and the potential for toxicity.

  13. Persistent perfluorinated acids in seafood collected from two cities of China.

    PubMed

    Gulkowska, Anna; Jiang, Qinting; So, Man Ka; Taniyasu, Sachi; Lam, Paul K S; Yamashita, Nobuyoshi

    2006-06-15

    As an initial survey of human exposure to perfluorinated acids through food consumption in China, seven types of seafood collected from fish markets in two coastal cities were analyzed. Nine perfluorinated compounds were determined using HPLC coupled with ESI-MS/MS. Perfluorooctane sulfonate (PFOS) was the predominant fluorochemical and was found in all 27 seafood samples, including fish, molluscs, crabs, shrimp, oysters, mussels, and clams. Concentrations of PFOS in seafood samples ranged from 0.3 to 13.9 ng/g wet weight, with the highest concentration in mantis shrimp. The hazard ratios of noncancer risk through seafood consumption based on PFOS and perfluorooctanoic acid concentrations were calculated and were less than unity. PMID:16830535

  14. Electrolytic production of neodymium without perfluorinated carbon compounds on the offgases

    DOEpatents

    Keller, R.; Larimer, K.T.

    1998-09-22

    A method is described for producing neodymium in an electrolytic cell without formation of perfluorinated carbon gases (PFCs), the method comprising the steps of providing an electrolyte in the electrolytic cell and providing an anode in an anode region of the electrolyte and providing a cathode in a cathode region of the electrolytic cell. Dissolving an oxygen-containing neodymium compound in the electrolyte in the anode region and maintaining a more intense electrolyte circulation in the anode region than in the cathode region. Passing an electrolytic current between said anode and said cathode and depositing neodymium metal at the cathode, preventing the formation of perfluorinated carbon gases by limiting anode over voltage. 4 figs.

  15. 30 CFR 28.2 - Approved fuses.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-circuit protection for trailing cables in coal mines only where such fuses are: (1) The same in all... Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS FUSES FOR USE WITH DIRECT CURRENT IN PROVIDING SHORT-CIRCUIT PROTECTION FOR...

  16. 30 CFR 28.2 - Approved fuses.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-circuit protection for trailing cables in coal mines only where such fuses are: (1) The same in all... Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS FUSES FOR USE WITH DIRECT CURRENT IN PROVIDING SHORT-CIRCUIT PROTECTION FOR...

  17. 30 CFR 28.2 - Approved fuses.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-circuit protection for trailing cables in coal mines only where such fuses are: (1) The same in all... Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS FUSES FOR USE WITH DIRECT CURRENT IN PROVIDING SHORT-CIRCUIT PROTECTION FOR...

  18. 30 CFR 28.2 - Approved fuses.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-circuit protection for trailing cables in coal mines only where such fuses are: (1) The same in all... Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS FUSES FOR USE WITH DIRECT CURRENT IN PROVIDING SHORT-CIRCUIT PROTECTION FOR...

  19. Blast Off into Space Science with Fuses.

    ERIC Educational Resources Information Center

    Bombaugh, Ruth

    2000-01-01

    Introduces an activity in which students build a fuse with steel, wood, light bulbs, copper wire, clay, and batteries. Uses the cross-age instructional approach to teach about the value of instructional time. Contains directions for building a fuse. (YDS)

  20. Precise Sealing of Fused-Quartz Ampoules

    NASA Technical Reports Server (NTRS)

    Debnan, W. J. J.; Clark, I. O.

    1982-01-01

    New technique rapidly evacuates and seals fused-quartz ampoule with precise clearance over contents without appreciably thinning ampoule walls. Quartz plug is lowered into working section of ampoule after ampoule has been evacuated. Plug is then fused to ampoule walls, forming vacuum seal. New technique maintains wall strength and pumping speed.

  1. 30 CFR 18.52 - Renewal of fuses.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Renewal of fuses. 18.52 Section 18.52 Mineral... § 18.52 Renewal of fuses. Enclosure covers that provide access to fuses, other than headlight, control-circuit, and handheld-tool fuses, shall be interlocked with a circuit-interrupting device. Fuses shall...

  2. Uptake of perfluorinated alkyl acids by hydroponically grown lettuce (Lactuca sativa).

    PubMed

    Felizeter, Sebastian; McLachlan, Michael S; de Voogt, Pim

    2012-11-01

    An uptake study was carried out to assess the potential human exposure to perfluorinated alkyl acids (PFAAs) through the ingestion of vegetables. Lettuce (Lactuca sativa) was grown in PFAA-spiked nutrient solutions at four different concentrations, ranging from 10 ng/L to 10 μg/L. Eleven perfluorinated carboxylic acids (PFCAs) and three perfluorinated sulfonic acids (PFSAs) were analyzed by HPLC-MS/MS. At the end of the experiment, the major part of the total mass of each of the PFAAs (except the short-chain, C4-C7, PFCAs) taken up by plants appeared to be retained in the nonedible part, viz. the roots. Root concentration factors (RCF), foliage/root concentration factors (FRCF), and transpiration stream concentration factors (TSCF) were calculated. For the long chained PFAAs, RCF values were highest, whereas FRCF were lowest. This indicates that uptake by roots is likely governed by sorption of PFAAs to lipid-rich root solids. Translocation from roots to shoots is restricted and highly depending on the hydrophobicity of the compounds. Although the TSCF show that longer-chain PFCAs (e.g., perfluorododecanoic acid) get better transferred from the nutrient solution to the foliage than shorter-chain PFCAs (e.g., perfluoroheptanoic acid), the major fraction of longer-chain PFCAs is found in roots due to additional adsorption from the spiked solution. Due to the strong electron-withdrawing effect of the fluorine atoms the role of the negative charge of the dissociated PFAAs is likely insignificant.

  3. Occurrence of pharmaceuticals, hormones, and perfluorinated compounds in groundwater in Taiwan.

    PubMed

    Lin, Yen-Ching; Lai, Webber Wei-Po; Tung, Hsin-hsin; Lin, Angela Yu-Chen

    2015-05-01

    In this work, we investigated the emerging pollutants in Taiwanese groundwater for the first time and correlated their presence with possible contamination sources. Fifty target pharmaceuticals and perfluorinated chemicals in groundwater were mostly present at ng L(-1) concentrations, except for 17α-ethynylestradiol, sulfamethoxazole, and acetaminophen (maximums of 1822, 1820, and 1036 ng L(-1), respectively). Perfluorinated compounds were detected with the highest frequencies in groundwater at almost all of the sample sites, especially short-chained perfluorinated carboxylates, which were easily transferred to the groundwater. The results indicate that the compounds found to have high detection frequencies and concentrations in groundwater are similar to those found in other countries around the world. Most common pharmaceuticals that contain hydrophilic groups, such as sulfonamide antibiotics and caffeine, are easily transported through surface waters to groundwater. The results also indicated that the persistent natures of emerging contaminants with high detection frequencies in surface water and groundwater, such as perfluorooctanesulfonate (risk quotient >1), caffeine, and carbamazepine, should be further studied and evaluated.

  4. Microgravity Manufacturing Via Fused Deposition

    NASA Technical Reports Server (NTRS)

    Cooper, K. G.; Griffin, M. R.

    2003-01-01

    Manufacturing polymer hardware during space flight is currently outside the state of the art. A process called fused deposition modeling (FDM) can make this approach a reality by producing net-shaped components of polymer materials directly from a CAE model. FDM is a rapid prototyping process developed by Stratasys, Inc.. which deposits a fine line of semi-molten polymer onto a substrate while moving via computer control to form the cross-sectional shape of the part it is building. The build platen is then lowered and the process is repeated, building a component directly layer by layer. This method enables direct net-shaped production of polymer components directly from a computer file. The layered manufacturing process allows for the manufacture of complex shapes and internal cavities otherwise impossible to machine. This task demonstrated the benefits of the FDM technique to quickly and inexpensively produce replacement components or repair broken hardware in a Space Shuttle or Space Station environment. The intent of the task was to develop and fabricate an FDM system that was lightweight, compact, and required minimum power consumption to fabricate ABS plastic hardware in microgravity. The final product of the shortened task turned out to be a ground-based breadboard device, demonstrating miniaturization capability of the system.

  5. Laser welding of fused quartz

    DOEpatents

    Piltch, Martin S.; Carpenter, Robert W.; Archer, III, McIlwaine

    2003-06-10

    Refractory materials, such as fused quartz plates and rods are welded using a heat source, such as a high power continuous wave carbon dioxide laser. The radiation is optimized through a process of varying the power, the focus, and the feed rates of the laser such that full penetration welds may be accomplished. The process of optimization varies the characteristic wavelengths of the laser until the radiation is almost completely absorbed by the refractory material, thereby leading to a very rapid heating of the material to the melting point. This optimization naturally occurs when a carbon dioxide laser is used to weld quartz. As such this method of quartz welding creates a minimum sized heat-affected zone. Furthermore, the welding apparatus and process requires a ventilation system to carry away the silicon oxides that are produced during the welding process to avoid the deposition of the silicon oxides on the surface of the quartz plates or the contamination of the welds with the silicon oxides.

  6. 49 CFR 173.184 - Highway or rail fusee.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... effects for signaling purposes. The composition of the fusee must be such that the fusee will not ignite... consecutive hours. (b) Fusees (highway and railway) must be packaged in steel drums (1A2), steel...

  7. Launch of NASA's FUSE satellite from CCAS.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The Boeing Delta II rocket carrying NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite clears the tower after liftoff at 11:44 a.m. EDT from Launch Pad 17A, Cape Canaveral Air Station. FUSE was developed to investigate the origin and evolution of the lightest elements in the universe - hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum.

  8. Workers at CCAS move the FUSE satellite.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite stands in the Hangar A&E, Cape Canaveral Air Station (CCAS), ready for its launch, targeted for June 23 from Launch Pad 17A, CCAS aboard a Boeing Delta II rocket. FUSE was developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., to investigate the origin and evolution of the lightest elements in the universe - hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum.

  9. Launch of NASA's FUSE satellite from CCAS.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite sits on Launch Pad 17A, Cape Canaveral Air Station, aboard the Boeing Delta II rocket waiting for launch. Liftoff is scheduled for 11:39 a.m. EDT. FUSE was developed to investigate the origin and evolution of the lightest elements in the universe - hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum.

  10. Launch of NASA's FUSE satellite from CCAS.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    As light peers over the horizon at the crack of dawn, NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite waits for launch on Launch Pad 17A, Cape Canaveral Air Station, aboard the Boeing Delta II rocket. Liftoff is scheduled for 11:39 a.m. EDT. FUSE was developed to investigate the origin and evolution of the lightest elements in the universe - hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum.

  11. Launch of NASA's FUSE satellite from CCAS.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Clouds of smoke and steam billow around the Boeing Delta II rocket as it roars into the sky after liftoff at 11:44 a.m. EDT from Launch Pad 17A, Cape Canaveral Air Station. The rocket is carrying NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. FUSE was developed to investigate the origin and evolution of the lightest elements in the universe - hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum.

  12. Regioselective Oxidation of Fused-Pentagon Chlorofullerenes.

    PubMed

    Zhang, Zhen-Qiang; Chen, Shu-Fen; Gao, Cong-Li; Zhou, Ting; Shan, Gui-Juan; Tan, Yuan-Zhi; Xie, Su-Yuan; Huang, Rong-Bin; Zheng, Lan-Sun

    2016-01-19

    Two monoxides of typical smaller chlorofullerenes, (#271)C50Cl10O and (#913)C56Cl10O, featured with double-fused-pentagons, were synthesized to demonstrate further regioselective functionalization of non-IPR (IPR = isolated pentagon rule) chlorofullerenes. Both non-IPR chlorofullerene oxides exhibit an epoxy structure at the ortho-site of fused pentagons. In terms of the geometrical analysis and theoretical calculations, the principles for regioselective epoxy oxidation of non-IPR chlorofullerenes are revealed to follow both "fused-pentagon ortho-site" and "olefinic bond" rules, which are valuable for prediction of oxidation of non-IPR chlorofullerenes. PMID:26726707

  13. Fused Silica and Other Transparent Window Materials

    NASA Technical Reports Server (NTRS)

    Salem, Jon

    2016-01-01

    Several transparent ceramics, such as spinel and AlONs are now being produced in sufficient large areas to be used in space craft window applications. The work horse transparent material for space missions from Apollo to the International Space Station has been fused silica due in part to its low coefficient of expansion and optical quality. Despite its successful use, fused silica exhibits anomalies in its crack growth behavior, depending on environmental preconditioning and surface damage. This presentation will compare recent optical ceramics to fused silica and discuss sources of variation in slow crack growth behavior.

  14. Fluorine-Based DRIE of Fused Silica

    NASA Technical Reports Server (NTRS)

    Yee, Karl; Shcheglov, Kirill; Li, Jian; Choi, Daniel

    2007-01-01

    A process of deep reactive-ion etching (DRIE) using a fluorine-based gas mixture enhanced by induction-coupled plasma (ICP) has been demonstrated to be effective in forming high-aspect-ratio three-dimensional patterns in fused silica. The patterns are defined in part by an etch mask in the form of a thick, high-quality aluminum film. The process was developed to satisfy a need to fabricate high-aspect-ratio fused-silica resonators for vibratory microgyroscopes, and could be used to satisfy similar requirements for fabricating other fused-silica components.

  15. Subcritical fatigue in fuse networks

    NASA Astrophysics Data System (ADS)

    Oliveira, C. L. N.; Vieira, A. P.; Herrmann, H. J.; Andrade, J. S., Jr.

    2012-11-01

    We obtain the Paris law of fatigue crack propagation in a fuse network model where the accumulated damage in each resistor increases with time as a power law of the local current amplitude. When a resistor reaches its fatigue threshold, it burns irreversibly. Over time, this drives cracks to grow until the system is fractured into two parts. We study the relation between the macroscopic exponent of the crack-growth rate —entering the phenomenological Paris law— and the microscopic damage accumulation exponent, γ, under the influence of disorder. The way the jumps of the growing crack, Δa, and the waiting time between successive breaks, Δt, depend on the type of material, via γ, are also investigated. We find that the averages of these quantities, \\left \\langle \\Delta a\\right \\rangle and \\left \\langle \\Delta t\\right \\rangle /\\left \\langle t_r\\right \\rangle , scale as power laws of the crack length a, \\left \\langle \\Delta a\\right \\rangle \\propto a^{\\alpha } and \\left \\langle \\Delta t\\right \\rangle /\\left \\langle t_r\\right \\rangle \\propto a^{-\\beta } , where \\left \\langle t_r\\right \\rangle is the average rupture time. Strikingly, our results show, for small values of γ, a decrease in the exponent of the Paris law in comparison with the homogeneous case, leading to an increase in the lifetime of breaking materials. For the particular case of γ = 0, when fatigue is exclusively ruled by disorder, an analytical treatment confirms the results obtained by simulation.

  16. 1,3-Bis[2-(2-oxo-1,3-oxazolidin-3-yl)eth­yl]-1H-benzimidazol-2(3H)-one

    PubMed Central

    Ouzidan, Younes; Kandri Rodi, Youssef; Fronczek, Frank R.; Venkatraman, Ramaiyer; El Ammari, Lahcen; Essassi, El Mokhtar

    2011-01-01

    The mol­ecular structure of the title compound, C17H20N4O5, contains a central fused-ring system, comprised of six- and five-membered rings. This unit is linked by C2 chains to two 2-oxo-1,3-oxazolidine five-membered rings. The central fused-ring system is essentially planar, with a maximum deviation of 0.008 (1) Å from the mean plane. Both oxazolidine five-membered rings are also nearly planar, with maximum deviations of 0.090 (1) and 0.141 (1) Å. PMID:21523041

  17. Fuse Protects Parabolic-Dish Solar Collector

    NASA Technical Reports Server (NTRS)

    Selcuk, M. K.

    1983-01-01

    Sliding barrel and shutter protect against overheating. Downward movement of shutter initiated by melting of fuse wire that suspends it. Shutter lowered or raised under operator's control by depressuring or pressurizing hydraulic cylinder.

  18. Organometallic chemistry: Fused ferrocenes come full circle

    NASA Astrophysics Data System (ADS)

    Musgrave, Rebecca A.; Manners, Ian

    2016-09-01

    Chemists have long been fascinated by electron delocalization, from both a fundamental and applied perspective. Macrocyclic oligomers containing fused ferrocenes provide a new structural framework -- containing strongly interacting metal centres -- that is capable of supporting substantial charge delocalization.

  19. The Legacy of the FUSE Mission

    NASA Technical Reports Server (NTRS)

    Sonneborne, George

    2012-01-01

    The Far Ultraviolet Spectroscopic Explorer (FUSE) mission was a far-ultraviolet space telescope that performed high resolution (R=20,OOO) spectroscopy in the 905 - 1187 A spectral range. FUSE primarily observed stars and distant galaxies to study interstellar and intergalactic gas through absorption spectroscopy, as well as the properties of the objects themselves. This capability complemented the Hubble Space Telescope at longer wavelengths, and provided the international astronomical community with access to an important part of the electromagnetic spectrum. FUSE was a joint project of NASA, CNES, and CSA. The mission operated from 1999 to 2007. This review talk will summarize the scientific impact of the FUSE mission on several key scientific problems, as well as lessons learned for future mission concepts.

  20. Coordination chemistry in fused-salt solutions

    NASA Technical Reports Server (NTRS)

    Gruen, D. M.

    1969-01-01

    Spectrophotometric work on structural determinations with fused-salt solutions is reviewed. Constraints placed on the method, as well as interpretation of the spectra, are discussed with parallels drawn to aqueous spectrophotometric curves of the same materials.

  1. Electrodeposition of microcrystalline chromium from fused salts

    SciTech Connect

    Vargas, T.; Varma, R.; Brown, A.

    1987-01-01

    Chromium can be conveniently electroplated from fused chloride electrolytes. The deposition from LiCl-KCl (eutectic)-CrCl/sub 2/ melts is known to produce large crystal grains. Large grain size and other problems encountered in the electrodeposition of microcrystalline chromium from fused salt are discussed. The results indicate that combined use of forced electrolyte convection and a nucleating pulse in conjunction with a periodic reverse pulse produces fine-grained deposits.

  2. RHEOLOGICAL PROPERTIES & MOLECULAR WEIGHT DISTRIBUTIONS OF FOUR PERFLUORINATED THERMOPLASTIC POLYMERS

    SciTech Connect

    Hoffman, D M; Shields, A L

    2009-02-24

    Dynamic viscosity measurements and molecular weight estimates have been made on four commercial, amorphous fluoropolymers with glass transitions (Tg) above 100 C: Teflon AF 1600, Hyflon AD 60, Cytop A and Cytop M. These polymers are of interest as binders for the insensitive high explosive 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) because of their high density and Tg above ambient, but within a suitable processing range of TATB. As part of this effort, the rheological properties and molecular weight distributions of these polymers were evaluated.

  3. 1,3,5-Trinitrobenzene

    Integrated Risk Information System (IRIS)

    1,3,5 - Trinitrobenzene ; CASRN 99 - 35 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcino

  4. Uptake of perfluorinated alkyl acids by hydroponically grown lettuce (Lactuca sativa).

    PubMed

    Felizeter, Sebastian; McLachlan, Michael S; de Voogt, Pim

    2012-11-01

    An uptake study was carried out to assess the potential human exposure to perfluorinated alkyl acids (PFAAs) through the ingestion of vegetables. Lettuce (Lactuca sativa) was grown in PFAA-spiked nutrient solutions at four different concentrations, ranging from 10 ng/L to 10 μg/L. Eleven perfluorinated carboxylic acids (PFCAs) and three perfluorinated sulfonic acids (PFSAs) were analyzed by HPLC-MS/MS. At the end of the experiment, the major part of the total mass of each of the PFAAs (except the short-chain, C4-C7, PFCAs) taken up by plants appeared to be retained in the nonedible part, viz. the roots. Root concentration factors (RCF), foliage/root concentration factors (FRCF), and transpiration stream concentration factors (TSCF) were calculated. For the long chained PFAAs, RCF values were highest, whereas FRCF were lowest. This indicates that uptake by roots is likely governed by sorption of PFAAs to lipid-rich root solids. Translocation from roots to shoots is restricted and highly depending on the hydrophobicity of the compounds. Although the TSCF show that longer-chain PFCAs (e.g., perfluorododecanoic acid) get better transferred from the nutrient solution to the foliage than shorter-chain PFCAs (e.g., perfluoroheptanoic acid), the major fraction of longer-chain PFCAs is found in roots due to additional adsorption from the spiked solution. Due to the strong electron-withdrawing effect of the fluorine atoms the role of the negative charge of the dissociated PFAAs is likely insignificant. PMID:23043263

  5. Perfluorinated compounds in aquatic organisms at various trophic levels in a Great Lakes food chain.

    PubMed

    Kannan, Kurunthachalam; Tao, Lin; Sinclair, Ewan; Pastva, Stephanie D; Jude, Dave J; Giesy, John P

    2005-05-01

    Trophic transfer of perfluorooctanesulfonate (PFOS) and other related perfluorinated compounds was examined in a Great Lakes benthic foodweb including water-algae-zebra mussel-round goby-smallmouth bass. In addition, perfluorinated compounds were measured in livers and eggs of Chinook salmon and lake whitefish, in muscle tissue of carp, and in eggs of brown trout collected from Michigan. Similarly, green frog livers, snapping turtle plasma, mink livers, and bald eagle tissues were analyzed to determine concentrations in higher trophic-level organisms in the food chain. PFOS was the most widely detected compound in benthic organisms at various trophic levels. Concentrations of PFOS in benthic invertebrates such as amphipods and zebra mussels were approximately 1000-fold greater than those in surrounding water, which suggested a bioconcentration factor (BCF; concentration in biota/concentration in water) of 1000 in benthic invertebrates. Concentrations of PFOS in round gobies were two- to fourfold greater than those in their prey organisms such as zebra mussels and amphipods. Concentrations of PFOS in predatory fishes (Chinook salmon and lake whitefish) were 10 to 20-fold greater than those in their prey species. Concentrations of PFOS in mink and bald eagles were, on average, 5- to 10-fold greater than those in Chinook salmon, carp, or snapping turtles. Because of the accumulation of PFOS in liver and blood, the biomagnification factor (BMF) of perfluorinated compounds in higher trophic-level organisms such as salmonid fishes, mink, and eagles were based on the concentrations in livers or plasma. Overall, these results suggest a BCF of PFOS of approximately 1000 (whole-body based) in benthic invertebrates, and a BMF of 10 to 20 in mink or bald eagles, relative to their prey items. Eggs of fish contained notable concentrations of PFOS, suggesting oviparous transfer of this compound. PFOA was found in water, but its biomagnification potential was lower than that of

  6. Intramolecular 1,3-dipolar cycloaddition reactions in the synthesis of complex annelated quinolines, α-carbolines and coumarins.

    PubMed

    Majumder, Swarup; Borah, Pallabi; Bhuyan, Pulak J

    2012-05-01

    In this study, we report the synthesis of several novel dihydroisoxazole-, tetrahydroisoxazole- and dihydropyrazole-fused pyrido[2,3-b]quinolines, α-carbolines, and pyrido[2,3-c]coumarins, respectively, from simple precursors and by exploring intramolecular 1,3-dipolar cycloaddition reactions involving nitrile oxides, nitrones, and nitrile imines as 1,3-dipoles. PMID:22374452

  7. Modification of epoxy-reinforced glass-cloth composites with a perfluorinated alkyl ether elastomer

    NASA Technical Reports Server (NTRS)

    Rosser, R. W.; Chen, T. S.; Taylor, M.

    1984-01-01

    A perfluorinated alkyl ether diacyl fluoride prepolymer (molecular weight about 1500) was coreacted with Epon 828 epoxy resin and diamino diphenyl sulfone to obtain an elastomer-toughened, glass-cloth composite. Improvements in flexural toughness, impact resistance, and water resistance, without loss of strength, modulus of elasticity or a lowering of the glass-transition temperature, were realized over those of the unmodified composite. Factors concerning optimization of the process are discussed. Results suggest that a simultaneously interpenetrating polymer network may be formed which gives rise to a measured improvement in composite mechanical properties.

  8. Perfluorinated alcohols and acids induce coacervation in aqueous solutions of amphiphiles.

    PubMed

    Khaledi, Morteza G; Jenkins, Samuel I; Liang, Shuang

    2013-02-26

    We have discovered that water-miscible perfluorinated alcohols and acids (FA) can induce simple and complex coacervation in aqueous solutions of a wide range of amphiphilic molecules such as synthetic surfactants, phospholipids, and bile salts as well as polyelectrolytes. This unique phenomenon seems to be nearly ubiquitous, especially for complex coacervate systems composed of mixed catanionic amphiphiles. In addition, coacervation and aqueous phase separation were observed over a wide range of surfactants concentrations and for different mole fractions of the oppositely charged amphiphile.

  9. Formation of perfluorinated surfactants from precursors by indigenous microorganisms in groundwater.

    PubMed

    Murakami, Michio; Nishikoori, Hiroshi; Sakai, Hiroshi; Oguma, Kumiko; Takada, Hideshige; Takizawa, Satoshi

    2013-09-01

    The formation of perfluorinated surfactants (PFSs) from their precursors in waters is of concern. In this study, the formation of PFSs through biodegradation of precursors was measured in incubation tests. Indigenous microorganisms in groundwater were able to biodegrade perfluorooctane sulfonamide (FOSA) to yield perfluorooctane sulfonate (PFOS). The addition of nutrients and soil promoted the formation. A 42-d incubation test using sources of groundwater recharge showed that PFOS, perfluorooctanoate, and perfluorononanoate were significantly and remarkably (⩾1.5×) formed from precursors in street runoff through biodegradation, but not in rainwater or wastewater effluent. Significant formation of PFSs from precursors in street runoff was observed. PMID:23746363

  10. The application of Dow Chemical's perfluorinated membranes in proton-exchange membrane fuel cells

    NASA Technical Reports Server (NTRS)

    Eisman, G. A.

    1989-01-01

    Dow Chemical's research activities in fuel cell devices revolves around the development and subsequent investigation of the perfluorinated inomeric membrane separator useful in proton-exchange membrane systems. Work is currently focusing on studying the effects of equivalent weight, thickness, water of hydration, pretreatment procedures, as well as the degree of water management required for a given membrane separator in the cell. The presentation will include details of certain aspects of the above as well as some of the requirements for high and low power generation.

  11. Formation of perfluorinated surfactants from precursors by indigenous microorganisms in groundwater.

    PubMed

    Murakami, Michio; Nishikoori, Hiroshi; Sakai, Hiroshi; Oguma, Kumiko; Takada, Hideshige; Takizawa, Satoshi

    2013-09-01

    The formation of perfluorinated surfactants (PFSs) from their precursors in waters is of concern. In this study, the formation of PFSs through biodegradation of precursors was measured in incubation tests. Indigenous microorganisms in groundwater were able to biodegrade perfluorooctane sulfonamide (FOSA) to yield perfluorooctane sulfonate (PFOS). The addition of nutrients and soil promoted the formation. A 42-d incubation test using sources of groundwater recharge showed that PFOS, perfluorooctanoate, and perfluorononanoate were significantly and remarkably (⩾1.5×) formed from precursors in street runoff through biodegradation, but not in rainwater or wastewater effluent. Significant formation of PFSs from precursors in street runoff was observed.

  12. 29 CFR 1926.907 - Use of safety fuse.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Use of safety fuse. 1926.907 Section 1926.907 Labor... of safety fuse. (a) Safety fuse shall only be used where sources of extraneous electricity make the use of electric blasting caps dangerous. The use of a fuse that has been hammered or injured in...

  13. Thermographic Observation Of Pyrotechnic Fuse Failure

    NASA Astrophysics Data System (ADS)

    Abney, Linda D.; Mohler, Jonathan H.

    1987-05-01

    Certain metal combinations alloy, with release of large amounts of energy. Palladium/Aluminum is available commercially in the form of wire, braid and foil of various diameters and thicknesses. These products are useful as heat sources and as fuses to ignite other pyrotechnic compositions. We have found that when used in small devices, where the fuse wire may be required to go through narrow channels and sharp bends, the alloying reaction may not propagate reliably. We have used infrared thermography to monitor heat flow in the fuse wire and in materials surrounding it, to observe the thermal dynamics involved in fuse wire propagation. Fuse wire can be ignited by passing an electrical current through it from end to end or it can be lit from one end to carry ignition to other locations in a device or system. Two effects have been observed thermographically: Conductive cooling of the wire where effective thermal contact occurs and hot zone formation at stress points produced by sharp bends. Thermographic measurements have demonstrated that when electrical current is used to ignite palladium/aluminum wire or braid, reaction begins farthest from a heat sink region, or at a sharp bend.The problem with high thermal contact is easily understood since heat sinking can cool the fuse wire and retard reaction, even to the point of failure. Hot zone formation at high stress regions may, on the other hand, not appear detrimental. However, if one recognizes that these hot zones result from high electrical resistance, probably due to microscopic cracks formed in the palladium sheath of the fuse wire, it is easy to see that a corresponding thermal resistance will also be present. Such a high thermal resistance point, when coupled with adjacent conductive cooling paths can contribute to fuse failure.By using infrared scanning, one can not only observe the importance of such effects in fuse wire ignition and propagation but also see where they may be occurring in a particular

  14. Wafer-fused semiconductor radiation detector

    DOEpatents

    Lee, Edwin Y.; James, Ralph B.

    2002-01-01

    Wafer-fused semiconductor radiation detector useful for gamma-ray and x-ray spectrometers and imaging systems. The detector is fabricated using wafer fusion to insert an electrically conductive grid, typically comprising a metal, between two solid semiconductor pieces, one having a cathode (negative electrode) and the other having an anode (positive electrode). The wafer fused semiconductor radiation detector functions like the commonly used Frisch grid radiation detector, in which an electrically conductive grid is inserted in high vacuum between the cathode and the anode. The wafer-fused semiconductor radiation detector can be fabricated using the same or two different semiconductor materials of different sizes and of the same or different thicknesses; and it may utilize a wide range of metals, or other electrically conducting materials, to form the grid, to optimize the detector performance, without being constrained by structural dissimilarity of the individual parts. The wafer-fused detector is basically formed, for example, by etching spaced grooves across one end of one of two pieces of semiconductor materials, partially filling the grooves with a selected electrical conductor which forms a grid electrode, and then fusing the grooved end of the one semiconductor piece to an end of the other semiconductor piece with a cathode and an anode being formed on opposite ends of the semiconductor pieces.

  15. Fused silica windows for solar receiver applications

    NASA Astrophysics Data System (ADS)

    Hertel, Johannes; Uhlig, Ralf; Söhn, Matthias; Schenk, Christian; Helsch, Gundula; Bornhöft, Hansjörg

    2016-05-01

    A comprehensive study of optical and mechanical properties of quartz glass (fused silica) with regard to application in high temperature solar receivers is presented. The dependence of rupture strength on different surface conditions as well as high temperature is analyzed, focussing particularly on damage by devitrification and sandblasting. The influence of typical types of contamination in combination with thermal cycling on the optical properties of fused silica is determined. Cleaning methods are compared regarding effectiveness on contamination-induced degradation for samples with and without antireflective coating. The FEM-aided design of different types of receiver windows and their support structure is presented. A large-scale production process has been developed for producing fused silica dome shaped windows (pressurized window) up to a diameter of 816 mm. Prototypes were successfully pressure-tested in a test bench and certified according to the European Pressure Vessel Directive.

  16. Propagation mechanism of polymer optical fiber fuse.

    PubMed

    Mizuno, Yosuke; Hayashi, Neisei; Tanaka, Hiroki; Nakamura, Kentaro; Todoroki, Shin-ichi

    2014-04-25

    A fiber fuse phenomenon in polymer optical fibers (POFs) has recently been observed, and its unique properties such as slow propagation, low threshold power density, and the formation of a black oscillatory damage curve, have been reported. However, its characterization is still insufficient to well understand the mechanism and to avoid the destruction of POFs. Here, we present detailed experimental and theoretical analyses of the POF fuse propagation. First, we clarify that the bright spot is not a plasma but an optical discharge, the temperature of which is ~3600 K. We then elucidate the reasons for the oscillation of the damage curve along with the formation of newly-observed gas bubbles as well as for the low threshold power density. We also present the idea that the POF fuse can potentially be exploited to offer a long photoelectric interaction length.

  17. Harnessing the fiber fuse for sensing applications.

    PubMed

    Lin, Guei-Ru; Baiad, Mohamad Diaa; Gagne, Mathieu; Liu, Wen-Fung; Kashyap, Raman

    2014-04-21

    A simple refractive index sensor based on a small section of fiber damaged by the fiber fuse is proposed and demonstrated with a sensitivity of 350.58 nm/refractive index unit (RIU). For comparison, a hetero-core structure fiber sensor composed of a short no-core fiber (NCF) sandwiched between two pieces of single-mode fibers is demonstrated with a sensitivity of 157.29 nm/RIU. The fiber fuse technique can allow mass production of sensors by incorporating small sections of the damaged fiber of any type into each device. We believe this is the first application of the periodic damage tracks in optical fibers formed by the fiber fuse.

  18. Propagation mechanism of polymer optical fiber fuse

    PubMed Central

    Mizuno, Yosuke; Hayashi, Neisei; Tanaka, Hiroki; Nakamura, Kentaro; Todoroki, Shin-ichi

    2014-01-01

    A fiber fuse phenomenon in polymer optical fibers (POFs) has recently been observed, and its unique properties such as slow propagation, low threshold power density, and the formation of a black oscillatory damage curve, have been reported. However, its characterization is still insufficient to well understand the mechanism and to avoid the destruction of POFs. Here, we present detailed experimental and theoretical analyses of the POF fuse propagation. First, we clarify that the bright spot is not a plasma but an optical discharge, the temperature of which is ~3600 K. We then elucidate the reasons for the oscillation of the damage curve along with the formation of newly-observed gas bubbles as well as for the low threshold power density. We also present the idea that the POF fuse can potentially be exploited to offer a long photoelectric interaction length. PMID:24762949

  19. Identifying the nonpoint source of perfluorinated compounds using a geographic information system based approach.

    PubMed

    Zushi, Yasuyuki; Masunaga, Shigeki

    2009-04-01

    Perfluorinated compounds (PFCs) have been detected in a wide range of places. They have also been reported to come from nonpoint sources, but the origin of these sources has not been identified. In the present study, we attempted to characterize the nonpoint source of PFCs in the Hayabuchi River, Japan, which runs through an urban area, using a geographic information system (GIS) and statistical analysis. We also estimated annual PFC loads from nonpoint sources in Japan as a whole, determining a magnitude comparable to that from sewage treatment plants (STPs); the range was a few tons per year for each PFC. Perfluorinated compound pollution in river water was found to increase when the river received drainage from an area with a high proportion of commercial and/or transportation land use. It was also found that more PFCs were discharged from the watersheds where train stations are located. This result could be interpreted as the use of land for commercial and transportation purposes is prevalent in close proximity to train stations, and that the effluents from those areas contain high concentrations of PFCs. These findings suggested that train stations could be indicators of nonpoint sources of PFCs.

  20. Mapping and Tuning the Fluorescence of Perfluorinated Polyanilines Synthesized through Liquid-Liquid Interfaces.

    PubMed

    Dallas, Panagiotis; Rašović, Ilija; Porfyrakis, Kyriakos

    2016-04-01

    A series of light-emitting perfluorinated polyanilines were synthesized by the oxidative polymerization of 3-perfluorooctyl aniline through a variety of aqueous/organic interfaces. According to the interfacial tension between the two solvents (the organic being chloroform, dichloromethane, perfluorinated ether, toluene, or o-dichlorobenzene), we obtain distinctive classes of materials based on the crystal packing, protonation, and oxidation state of the polymeric chains. We distinguish between soluble fractions with a distinctive, strong, and red-shifted photoluminescence pattern and an insoluble precipitate which can be subsequently solubilized in a mixture of acetone and toluene. The emission maximum for the insoluble fraction is located in the ultraviolet or blue region with a small Stokes shift; maxima for the soluble counterparts are in the green to yellow region. The soluble derivatives demonstrate a significantly smaller band gap compared to the monomer and large Stokes shifts up to 163 nm; the emission maximum for the most red-shifted emission was located at λ(em) = 548 nm. Their redox activity toward silver nanoparticles, their sensor reactivity with organic acid and bases, and the subsequent changes in the optical properties were demonstrated and the structure of the materials was evaluated with NMR, X-ray diffraction, and FTIR/Raman spectroscopy. PMID:26963137

  1. QSAR classification models for the screening of the endocrine-disrupting activity of perfluorinated compounds.

    PubMed

    Kovarich, S; Papa, E; Li, J; Gramatica, P

    2012-01-01

    Perfluorinated compounds (PFCs) are a class of emerging pollutants still widely used in different materials as non-adhesives, waterproof fabrics, fire-fighting foams, etc. Their toxic effects include potential for endocrine-disrupting activity, but the amount of experimental data available for these pollutants is limited. The use of predictive strategies such as quantitative structure-activity relationships (QSARs) is recommended under the REACH regulation, to fill data gaps and to screen and prioritize chemicals for further experimentation, with a consequent reduction of costs and number of tested animals. In this study, local classification models for PFCs were developed to predict their T4-TTR (thyroxin-transthyretin) competing potency. The best models were selected by maximizing the sensitivity and external predictive ability. These models, characterized by robustness, good predictive power and a defined applicability domain, were applied to predict the activity of 33 other PFCs of environmental concern. Finally, classification models recently published by our research group for T4-TTR binding of brominated flame retardants and for estrogenic and anti-androgenic activity were applied to the studied perfluorinated chemicals to compare results and to further evaluate the potential for these PFCs to cause endocrine disruption.

  2. Liquid-liquid interfaces of semifluorinated alkane diblock copolymers with water, alkanes, and perfluorinated alkanes.

    SciTech Connect

    Perahia, Dvora, Dr.; Pierce, Flint; Tsige, Mesfin; Grest, Gary Stephen, Dr.

    2008-08-01

    The liquid-liquid interface between semifluorinated alkane diblock copolymers of the form F3C(CF2)n-1-(CH2)m-1CH3 and water, protonated alkanes, and perfluorinated alkanes are studied by fully atomistic molecular dynamics simulations. A modified version of the OPLS-AA (Optimized Parameter for Liquid Simulation All-Atom) force field of Jorgensen et al. has been used to study the interfacial behavior of semifluorinated diblocks. Aqueous interfaces are found to be sharp, with correspondingly large values of the interfacial tension. Due to the reduced hydrophobicity of the protonated block compared to the fluorinated block, hydrogen enhancement is observed at the interface. Water dipoles in the interfacial region are found to be oriented nearly parallel to the liquid-liquid interface. A number of protonated alkanes and perfluorinated alkanes are found to be mutually miscible with the semifluorinated diblocks. For these liquids, interdiffusion follows the expected Fickian behavior, and concentration-dependent diffusivities are determined.

  3. Characterization of perfluorinated cation-exchange membranes MF-4SC surface modified with halloysite nanotubes

    NASA Astrophysics Data System (ADS)

    Filippov, A.; Afonin, D.; Kononenko, N.; Shkirskaya, S.

    2015-10-01

    The electrical conductivity and diffusion permeability through perfluorinated cation-exchange membranes MF-4SC (Russian analog of the Nafion-type membrane), whose surface is modified by nanotubes of halloysite using short exposures of low temperature microwave plasma, are theoretically investigated using the Nernst-Planck approach. The method of quantitative evaluation of physicochemical parameters (individual and averaged diffusion coefficients and averaged distribution coefficients of ion pairs in the membrane) of the systems `electrolyte solution - bi-layer ion-exchange membrane - water/electrolyte solution', which was proposed by us earlier, is further developed. The aforementioned parameters of modified MF-4SC/halloysite membranes were found using the least squares method. For this purpose we used electrical conductivity as well as diffusion permeability data experimentally obtained for NaCl and HCl solutions of different concentration. A new model of bi-layer membrane system can be used for refining the calculated results by taking into account the difference between co- and counter-ion diffusivities inside the membrane layers. We showed that grafting the layer of halloysite nanotubes onto the membrane surface noticeably affects the exchange capacity as well as the structural and transport characteristics of the original perfluorinated membrane. In particular, such a membrane may show weak asymmetry of diffusion permeability when its position inside a measuring cell is changed. Hybrid MF-4SC/halloysite membranes can thus be productively used in fuel cells and catalysis.

  4. Spatial and Temporal Patterns in Concentrations of Perfluorinated Compounds in Bald Eagle Nestlings in the Upper Midwestern United States

    EPA Science Inventory

    Perfluorinated chemicals (PFCs) are of concern due to their widespread use, persistence in the environment, tendency to accumulate in animal tissues, and growing evidence of toxicity. Between 2006 and 2011 we collected blood plasma from 261 bald eagle nestlings in six study areas...

  5. Treatment of sites contaminated with perfluorinated compounds using biochar amendment.

    PubMed

    Kupryianchyk, Darya; Hale, Sarah E; Breedveld, Gijs D; Cornelissen, Gerard

    2016-01-01

    Per- and polyfluorinated compounds (PFCs) have been attracting increasing attention due to their considerable persistence, bioaccumulation, and toxicity. Here, we studied the sorption behavior of three PFCs, viz. perfluorooctanesulfonic acid (PFOS), perfluorooctanecarboxylic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), on one activated carbon (AC) and two biochars from different feedstocks, viz. mixed wood (MW) and paper mill waste (PMW). In addition, we explored the potential of remediating three natively PFC contaminated soils by the addition of AC or biochar. The sorption coefficient i.e. Freundlich coefficients LogKF, (μg/kg)/(μg/L)(n), for the two biochars were 4.61±0.11 and 4.41±0.05 for PFOS, 3.02±0.04 and 3.01±0.01 for PFOA, and 3.21±0.07 and 3.18±0.03 for PFHxS, respectively. The AC sorbed the PFCs so strongly that aqueous concentrations were reduced to below detection limits, implying that the LogKF values were above 5.60. Sorption capacities decreased in the order: AC>MW>PMW, which was consistent with the material's surface area and pore size distribution. PFC sorption to MW biochar was near-linear (Freundlich exponent nF of 0.87-0.90), but non-linear for PMW biochar (0.64-0.73). Addition of the AC to contaminated soils resulted in almost complete removal of PFCs from the water phase and a significant (i.e. 1-3 Log unit) increase in soil-water distribution coefficient LogKd. However, small to no reduction in pore water concentration, and no effect on LogKd was found for the biochars. We conclude that amendment with AC but not biochar can be a useful method for in situ remediation of PFC-contaminated soils. PMID:25956025

  6. Perfluorinated carboxylic and sulphonic acids in surface water media from the regions of Tibetan Plateau: Indirect evidence on photochemical degradation?

    PubMed

    Yamazaki, Eriko; Falandysz, Jerzy; Taniyasu, Sachi; Hui, Ge; Jurkiewicz, Gabriela; Yamashita, Nobuyoshi; Yang, Yong-Liang; Lam, Paul K S

    2016-01-01

    Perfluorinated surfactants and repellents are synthetic substances that have found numerous industrial and customer applications. Due to their persistence, at least two groups of these substances-perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonic acids (PFSAs)-are diffused widely in the environment. It is hypothesized that the Tibetan Plateau, is one of few unique places on the Earth, due to its topography, specifically the vast space and high elevation above sea level, geographic location, climate, high solar radiation, lack of industry, little urbanization and general lack of significant direct sources of pollution. There it is believed possible to gain an insight into atmospheric fate (possible photochemical degradation of higher molecular mass and formation of lower molecular mass PFCAs and PFSAs) of PFASs under un-disturbed environmental conditions. Ultratrace analytical method for PFCAs and PFSAs and use of transportation and field blanks, laboratory blanks and isotopically labelled surrogates for recovery control has allowed the determination of nine perfluorinated carboxylic acids and six perfluorinated sulfonic acids at ultra-trace levels in water based samples from the alpine dimension regions of the Tibetan Plateau, the eastern slope of Minya Konka peak at the eastern edge of the Tibetan Plateau, and also from the city of Chengdu from the lowland of the Sichuan Province in China. The specific compositional pattern of PFCAs and PFSAs and low levels of pollution with those compounds were observed in the central region of the Tibetan Plateau and in the region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau. The fingerprint of the compositional pattern of PFCAs and PFSAs in water samples in the central region of the Tibetan Plateau and in the alpine region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau may be explained by the result of photochemical degradation with dealkylation of longer chain

  7. Fused quartz substrates for microchip electrophoresis

    SciTech Connect

    Jacobson, S.C.; Moore, A.W.; Ramsey, J.M.

    1995-07-01

    A fused quartz microchip is fabricated to perform capillary electrophoresis of metal ions complexed with 8-hydroxyquinoline-5-sulfonic acid (HQS). The channel manifold on the quartz substrate is fabricated using standard photolithographic, etching, and deposition techniques. By incorporating a direct bonding technique during the fabrication of the microchip, the substrate and cover plate can be fused together below the melting temperature for fused quartz. To enhance the resolution for the separation, the electroosmotic flow is minimized by covalently bonding polyacrylamide to the channel walls. A separation length of 16.5 mm and separation field strength of 870 V/cm enable separations to be performed in {<=}15 s. By increasing the concentration of HQS from 5 mM to 20 mM, the separation efficiency improves by approximately 3 times. The low background signal from the fused quartz substrate results in mass detection limits of 85, 61, and 134 amol and concentration detection limits of 46, 57, and 30 ppb for Zn, Cd, and Al, respectively. 30 refs., 6 figs., 2 tabs.

  8. 30 CFR 57.6502 - Safety fuse.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Safety fuse. 57.6502 Section 57.6502 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Nonelectric...

  9. 30 CFR 56.6502 - Safety fuse.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Safety fuse. 56.6502 Section 56.6502 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Nonelectric Blasting §...

  10. 30 CFR 57.6502 - Safety fuse.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Safety fuse. 57.6502 Section 57.6502 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Nonelectric...

  11. 30 CFR 57.6502 - Safety fuse.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Safety fuse. 57.6502 Section 57.6502 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Nonelectric...

  12. 30 CFR 56.6502 - Safety fuse.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Safety fuse. 56.6502 Section 56.6502 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Nonelectric Blasting §...

  13. 30 CFR 56.6502 - Safety fuse.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Safety fuse. 56.6502 Section 56.6502 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Nonelectric Blasting §...

  14. Crystal growth in fused solvent systems

    NASA Technical Reports Server (NTRS)

    Ulrich, D. R.; Noone, M. J.; Spear, K. E.; White, W. B.; Henry, E. C.

    1973-01-01

    Research is reported on the growth of electronic ceramic single crystals from solution for the future growth of crystals in a microgravity environment. Work included growth from fused or glass solvents and aqueous solutions. Topics discussed include: crystal identification and selection; aqueous solution growth of triglycine sulphate (TGS); and characterization of TGS.

  15. INHIBITION OF GAP JUNCTIONAL INTERCELLULAR COMMUNICATION BY PERFLUORINATED COMPOUNDS IN RAT LIVER AND DOLPHIN KIDNEY EPITHELIAL CELL LINES IN VITRO AND SPRAGUE-DAWLEY RATS IN VIVO

    EPA Science Inventory

    Abstract

    Gap Junctional Intercellular Communication (GJIC) is the major pathway of intercellular signal transduction, and is, thus, important for normal cell growth and function. Recent studies have revealed a global distribution of some perfluorinated organic compounds e...

  16. Anthropometry in 5- to 9-Year-Old Greenlandic and Ukrainian Children in Relation to Prenatal Exposure to Perfluorinated Alkyl Substances

    PubMed Central

    Ramlau-Hansen, Cecilia Høst; Vrijheid, Martine; Valvi, Damaskini; Pedersen, Henning Sloth; Zviezdai, Valentyna; Jönsson, Bo A.G.; Lindh, Christian H.; Bonde, Jens Peter; Toft, Gunnar

    2015-01-01

    Background In some animal studies, perfluorinated alkyl substances are suggested to induce weight gain. Human epidemiological studies investigating these associations are sparse. Objective We examined pregnancy serum concentrations of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) and the prevalence of offspring overweight (> 1 SD) and waist-to-height ratio (WHtR) > 0.5 at 5–9 years of age. Methods Sera from 1,022 pregnant women enrolled in the INUENDO cohort (2002–2004) from Greenland and Kharkiv (Ukraine) were analyzed for PFOA and PFOS using liquid chromatography–tandem mass spectrometry. Relative risks (RR) of being overweight and having WHtR > 0.5 in relation to continuous and categorized (tertiles) PFOA and PFOS were calculated at follow-up (2010–2012) using generalized linear models. Results Pooled PFOA median (range) was 1.3 (0.2–5.1) and PFOS median (range) was 10.8 (0.8–73.0) ng/mL. For each natural logarithm-unit (ln-unit) increase of pregnancy PFOA, the adjusted RR of offspring overweight was 1.11 [95% confidence interval (CI): 0.82, 1.53] in Greenlandic children. In Ukrainian children, the adjusted RR of offspring overweight was 1.02 (95% CI: 0.72, 1.44) for each ln-unit increase of pregnancy PFOA. Prenatal exposure to PFOS was not associated with overweight in country-specific or pooled analysis. The adjusted RR of having WHtR > 0.5 for each ln-unit increase of prenatal exposure to PFOA was 1.30 (95% CI: 0.97, 1.74) in the pooled analysis. For 1–ln-unit increase of prenatal exposure to PFOS, the adjusted RR of having a WHtR > 0.5 was 1.38 (95% CI: 1.05, 1.82) in the pooled analysis. Conclusions The results indicate that prenatal PFOA and PFOS exposures may be associated with child waist-to-height ratio > 0.5. Prenatal PFOA and PFOS exposures were not associated with overweight. Citation Høyer BB, Ramlau-Hansen CH, Vrijheid M, Valvi D, Pedersen HS, Zviezdai V, Jönsson BA, Lindh CH, Bonde JP, Toft G. 2015. Anthropometry

  17. FL V1.3

    2009-08-03

    A library of utility classes for computer vision. Contains implementations of various well-known image processing techniques, such as interest point operators and region descriptors. Includes interfaces to various libraries for image and video I/O, as well as an interface to LAPACK/BLAS. FL was developed at the University of Illinois, Urbana-Champaign (UIUC) and released under an open source license. Version 1.2 was a maintenance release provided by SNL under the LGPL license. Version 1.3 is amore » maintenance release, containing the following changes: - Improved image format handling. Now handles strided and planar memory layouts and a wider range of pixel formats. - Improved image file I/O, including better support for metadata, a wider range of stored pixel types, and a couple of new file formats. - Improvements to DOG and SIFT, and efficiency improvements in low-level convolution. - Improvements to networking, including a generic TCP listener. - Various improvements to numerical processing. The HISTORY file included in the distribution contains a more detailed description of the changes.« less

  18. FL V1.3

    SciTech Connect

    Rothganger, Frederick

    2009-08-03

    A library of utility classes for computer vision. Contains implementations of various well-known image processing techniques, such as interest point operators and region descriptors. Includes interfaces to various libraries for image and video I/O, as well as an interface to LAPACK/BLAS. FL was developed at the University of Illinois, Urbana-Champaign (UIUC) and released under an open source license. Version 1.2 was a maintenance release provided by SNL under the LGPL license. Version 1.3 is a maintenance release, containing the following changes: - Improved image format handling. Now handles strided and planar memory layouts and a wider range of pixel formats. - Improved image file I/O, including better support for metadata, a wider range of stored pixel types, and a couple of new file formats. - Improvements to DOG and SIFT, and efficiency improvements in low-level convolution. - Improvements to networking, including a generic TCP listener. - Various improvements to numerical processing. The HISTORY file included in the distribution contains a more detailed description of the changes.

  19. An electron-conducting pyrene-fused phenazinothiadiazole.

    PubMed

    Marco, A Belen; Cortizo-Lacalle, Diego; Gozalvez, Cristian; Olano, Mikel; Atxabal, Ainhoa; Sun, Xiangnan; Melle-Franco, Manuel; Hueso, Luis E; Mateo-Alonso, Aurelio

    2015-07-01

    A pyrene-fused phenazinothiadiazole that shows electron mobilities (μe = 0.016 cm(2) V(-1) s(-1)) two orders of magnitude higher than those reported for pyrene-fused pyrazaacenes is described. PMID:26051680

  20. Perfluorinated compounds in the Antarctic region: ocean circulation provides prolonged protection from distant sources.

    PubMed

    Bengtson Nash, Susan; Rintoul, Stephen R; Kawaguchi, So; Staniland, Iain; van den Hoff, John; Tierney, Megan; Bossi, Rossana

    2010-09-01

    In order to investigate the extent to which Perfluorinated Contaminants (PFCs) have permeated the Southern Ocean food web to date, a range of Antarctic, sub-Antarctic and Antarctic-migratory biota were analysed for key ionic PFCs. Based upon the geographical distribution pattern and ecology of biota with detectable vs. non-detectable PFC burdens, an evaluation of the potential contributory roles of alternative system input pathways is made. Our analytical findings, together with previous reports, reveal only the occasional occurrence of PFCs in migratory biota and vertebrate predators with foraging ranges extending into or north of the Antarctic Circumpolar Current (ACC). Geographical contamination patterns observed correspond most strongly with those expected from delivery via hydrospheric transport as governed by the unique oceanographic features of the Southern Ocean. We suggest that hydrospheric transport will form a slow, but primary, input pathway of PFCs to the Antarctic region.

  1. Degradation of Perfluorinated Ether Lubricants on Pure Aluminum Surfaces: Semiempirical Quantum Chemical Modeling

    NASA Technical Reports Server (NTRS)

    Slaby, Scott M.; Ewing, David W.; Zehe, Michael J.

    1997-01-01

    The AM1 semiempirical quantum chemical method was used to model the interaction of perfluoroethers with aluminum surfaces. Perfluorodimethoxymethane and perfluorodimethyl ether were studied interacting with aluminum surfaces, which were modeled by a five-atom cluster and a nine-atom cluster. Interactions were studied for edge (high index) sites and top (low index) sites of the clusters. Both dissociative binding and nondissociative binding were found, with dissociative binding being stronger. The two different ethers bound and dissociated on the clusters in different ways: perfluorodimethoxymethane through its oxygen atoms, but perfluorodimethyl ether through its fluorine atoms. The acetal linkage of perfluorodimeth-oxymethane was the key structural feature of this molecule in its binding and dissociation on the aluminum surface models. The high-index sites of the clusters caused the dissociation of both ethers. These results are consistent with the experimental observation that perfluorinated ethers decompose in contact with sputtered aluminum surfaces.

  2. Wear of Spur Gears Having a Dithering Motion and Lubricated with a Perfluorinated Polyether Grease

    NASA Technical Reports Server (NTRS)

    Krantz, Timothy; Oswald, Fred; Handschuh, Robert

    2007-01-01

    Gear contact surface wear is one of the important failure modes for gear systems. Dedicated experiments are required to enable precise evaluations of gear wear for a particular application. The application of interest for this study required evaluation of wear of gears lubricated with a grade 2 perfluorinated polyether grease and having a dithering (rotation reversal) motion. Experiments were conducted using spur gears made from AISI 9310 steel. Wear was measured using a profilometer at test intervals encompassing 10,000 to 80,000 cycles of dithering motion. The test load level was 1.1 GPa maximum Hertz contact stress at the pitch-line. The trend of total wear as a function of test cycles was linear, and the wear depth rate was approximately 1.2 nm maximum wear depth per gear dithering cycle. The observed wear rate was about 600 times greater than the wear rate for the same gears operated at high speed and lubricated with oil.

  3. Levels of perfluorinated compounds in raw and cooked Mediterranean finfish and shellfish.

    PubMed

    Vassiliadou, Irene; Costopoulou, Danae; Kalogeropoulos, Nick; Karavoltsos, Sotirios; Sakellari, Aikaterini; Zafeiraki, Effrosyni; Dassenakis, Manos; Leondiadis, Leondios

    2015-05-01

    Perfluorinated compounds (PFCs) were analyzed in several species of small Mediterranean fish and shellfish, all of which are popular in Greek diet. Analysis was conducted in raw samples and in samples cooked by the two ways preferred in Greek cuisine, i.e. fried in olive oil and grilled. PFCs above the detection limit were found in all raw samples except sardine, mussel and squid. The predominant PFC was PFOS (perfluorooctane sulfonate), the highest concentration of which was measured in picarel (20.4 ng g(-1) fresh weight). The PFOS values for the rest of the samples were between

  4. QENS investigation of proton confined motions in hydrated perfluorinated sulfonic membranes and self-assembled surfactants

    NASA Astrophysics Data System (ADS)

    Berrod, Quentin; Lyonnard, Sandrine; Guillermo, Armel; Ollivier, Jacques; Frick, Bernhard; Gébel, Gérard

    2015-01-01

    We report on QuasiElastic Neutron Scattering (QENS) investigations of the dynamics of protons and water molecules confined in nanostructured perfluorinated sulfonic acid (PFSA) materials, namely a commercial Aquivion membrane and the perfluorooctane sulfonic acid (PFOS) surfactant. The former is used as electrolyte in low-temperature fuel cells, while the latter forms mesomorphous self-assembled phases in water. The dynamics was investigated as a function of the hydration level, in a wide time range by combining time-of-flight and backscattering incoherent QENS experiments. Analysis of the quasielastic broadening revealed for both systems the existence of localized translational diffusive motions, fast rotational motions and slow hopping of protons in the vicinity of the sulfonic charges. The characteristic times and diffusion coefficients have been found to exhibit a very similar behaviour in both membrane and surfactant structures. Our study provides a comprehensive picture of the proton motion mechanisms and the dynamics of confined water in model and real PFSA nanostructures.

  5. Perfluorinated quaternary ammonium salts of polyoxometalate anions: Fluorous biphasic oxidation catalysis with and without fluorous solvents

    SciTech Connect

    Maayan, Galia; Fish, Richard H.; Neumann, Ronny

    2003-05-28

    Perfluorinated quaternary ammonium cations, [CF{sub 3}(CF{sub 2}){sub 7}(CH{sub 2}){sub 3}]{sub 3}CH{sub 3}N{sup +} (RFN{sup +}), were synthesized and used as counter cations for the [WZnM{sub 2}(H{sub 2}O){sub 2}(ZnW{sub 9}O{sub 34}){sub 2}]{sup 12-} (M = Mn(II), Zn(II)), polyoxometalate. The (RFN{sup +}){sub 12}[WZnM{sub 2}(H{sub 2}O){sub 2}(ZnW9O{sub 34}){sub 2}] compounds were fluorous biphasic catalysts for alcohol and alkenol oxidation, and alkene epoxidation with aqueous hydrogen peroxide. Reaction protocols with or without a fluorous solvent were tested. The catalytic activity and selectivity was affected both by the hydrophobicity of the solvent and the substrate.

  6. Retrograde intrarenal surgery in cross-fused ectopic kidney.

    PubMed

    Resorlu, Mustafa; Kabar, Mucahit; Resorlu, Berkan; Doluoglu, Omer Gokhan; Kilinc, Muhammet Fatih; Karakan, Tolga

    2015-02-01

    Cross-fused renal ectopia is a rare congenital anomaly in which both kidneys are fused and located on the same side. We report a case of right-to-left cross-fused renal ectopia and nephrolithiasis, in whom retrograde intrarenal surgery was used to treat the stone disease. To our knowledge, this is the first case of retrograde intrarenal surgery of a crossed-fused ectopic kidney. PMID:25481231

  7. Spatial and temporal trends of perfluorinated compounds in Beluga Whales (Delphinapterus leucas) from Alaska.

    PubMed

    Reiner, Jessica L; O'Connell, Steven G; Moors, Amanda J; Kucklick, John R; Becker, Paul R; Keller, Jennifer M

    2011-10-01

    Wildlife from remote locations have been shown to bioaccumulate perfluorinated compounds (PFCs) in their tissues. Twelve PFCs, consisting of perfluorinated carboxylic (PFCA) and sulfonic (PFSA) acids as well as the perfluorooctane sulfonate (PFOS) precursor perfluorooctane sulfonamide (PFOSA), were measured in livers of 68 beluga whales (Delphinapterus leucas) collected from two subpopulations, Cook Inlet and eastern Chukchi Sea, in Alaska between 1989 and 2006. PFOS and PFOSA were the dominant compounds measured in both beluga stock populations, with overall median concentrations of 10.8 ng/g and 22.8 ng/g, respectively. Long-chain perfluorocarboxylates, PFCAs (9 to 14 carbons), were detected in more than 80% of the samples. Perfluoroundecanoic acid (PFUnA) and perfluorotridecanoic acid (PFTriA) made up a large percentage of the PFCAs measured with median concentrations of 8.49 ng/g and 4.38 ng/g, respectively. To compare differences in location, year, sex, and length, backward stepwise multiple regression models of the individual and total PFC concentrations were used. Spatially, the Cook Inlet belugas had higher concentrations of most PFCAs and PFOS (p < 0.05); however, these belugas had a lower median concentration of PFOSA when compared to belugas from the eastern Chukchi Sea (p < 0.05). Temporal trends indicated most PFCAs, PFHxS, PFOS, and PFOSA concentrations increased from 1989 to 2006 (p < 0.05). Males had significantly higher concentrations of PFTriA, ΣPFCA, and PFOS (p < 0.05). Perfluorononanic acid (PFNA) and PFOS showed a significant decrease in concentration with increasing animal length (p < 0.05). These observations suggest the accumulation of PFCs in belugas is influenced by year, location, sex, and length.

  8. Mechanism of cytotoxic action of perfluorinated acids. III. Disturbance in Ca{sup 2+} homeostasis

    SciTech Connect

    Kleszczynski, Konrad; Skladanowski, Andrzej C.

    2011-03-01

    The global distribution of perfluorinated acids (PFAs) in industry and in household is well known. Their increasing environmental occurrence and biomagnification in the living organisms have drawn growing interests in efforts to describe precisely the mechanisms of action in vitro and in vivo. Our previous investigations widely described lipophilicity-dependent cytotoxicity of PFAs as well as the effect of perfluorination of carbon chain on depolarization of plasma membrane potential, acidification or mitochondrial dysfunctions. In this study we presented in dose- and time-dependent manner the impact of PFAs on calcium homeostasis in HCT116 cells. Comparative analysis of cytosolic [Ca{sup 2+}]{sub c} and mitochondrial calcium [Ca{sup 2+}]{sub m} carried out by flow cytometry revealed distinct uptake of calcium into mitochondria in correlation to increasing lipophilicity of PFAs. Massive accumulation of [Ca{sup 2+}]{sub m} was not accompanied by equivalent loss of [Ca{sup 2+}]{sub c}. Indeed, moderate changes of [Ca{sup 2+}]{sub c} were observed after incubation with 400 {mu}M PFDoDA reaching 29.83% and 49.17% decrease at 4th and 72nd hour, respectively. At the same time, mitochondrial calcium uptake increased from 2- to more than 4-fold comparing with non-treated cells. Incubation with non-fluorinated decanoic acid (DA) did not cause any changes in calcium homeostasis. Presented data show that PFAs-induced perturbations in calcium distribution seem to be a missing link related to mitochondria dysfunction playing a crucial role in determination of apoptotic cell death. Complete scheme for the mechanism of cytotoxic action of PFAs has been included.

  9. Perfluorinated alkyl acids in the plasma of South African crocodiles (Crocodylus niloticus).

    PubMed

    Christie, Ian; Reiner, Jessica L; Bowden, John A; Botha, Hannes; Cantu, Theresa M; Govender, Danny; Guillette, Matthew P; Lowers, Russell H; Luus-Powell, Wilmien J; Pienaar, Danie; Smit, Willem J; Guillette, Louis J

    2016-07-01

    Perfluorinated alkyl acids (PFAAs) are environmental contaminants that have been used in many products for over 50 years. Interest and concern has grown since 2000 on the widespread presence of PFAAs, when it was discovered that PFAAs were present in wildlife samples around the northern hemisphere. Since then, several studies have reported PFAAs in wildlife from many locations, including the remote regions of Antarctica and the Arctic. Although there are a multitude of studies, few have reported PFAA concentrations in reptiles and wildlife in the Southern Hemisphere. This study investigated the presence of PFAAs in the plasma of Nile crocodiles (Crocodylus niloticus) from South Africa. Crocodiles were captured from five sites in and around the Kruger National Park, South Africa, and plasma samples examined for PFAAs. Perfluorooctane sulfonate (PFOS) was the most frequent PFAA detected; with median values of 13.5 ng/g wet mass in crocodiles. In addition to PFOS, long chain perfluorinated carboxylic acids were also detected. Correlations between total length and PFAA load were investigated, as were differences in PFAA accumulation between sexes. No correlations were seen between crocodile size, nor were there sex-related differences. Spatial differences were examined and significant differences were observed in samples collected from the different sites (p < 0.05). Flag Boshielo Dam had the highest PFOS measurements, with a median concentration of 50.3 ng/g wet mass, when compared to the other sites (median concentrations at other sites below 14.0 ng/g wet mass). This suggests a point source of PFOS in this area.

  10. Perfluorinated alkyl acids in the plasma of South African crocodiles (Crocodylus niloticus).

    PubMed

    Christie, Ian; Reiner, Jessica L; Bowden, John A; Botha, Hannes; Cantu, Theresa M; Govender, Danny; Guillette, Matthew P; Lowers, Russell H; Luus-Powell, Wilmien J; Pienaar, Danie; Smit, Willem J; Guillette, Louis J

    2016-07-01

    Perfluorinated alkyl acids (PFAAs) are environmental contaminants that have been used in many products for over 50 years. Interest and concern has grown since 2000 on the widespread presence of PFAAs, when it was discovered that PFAAs were present in wildlife samples around the northern hemisphere. Since then, several studies have reported PFAAs in wildlife from many locations, including the remote regions of Antarctica and the Arctic. Although there are a multitude of studies, few have reported PFAA concentrations in reptiles and wildlife in the Southern Hemisphere. This study investigated the presence of PFAAs in the plasma of Nile crocodiles (Crocodylus niloticus) from South Africa. Crocodiles were captured from five sites in and around the Kruger National Park, South Africa, and plasma samples examined for PFAAs. Perfluorooctane sulfonate (PFOS) was the most frequent PFAA detected; with median values of 13.5 ng/g wet mass in crocodiles. In addition to PFOS, long chain perfluorinated carboxylic acids were also detected. Correlations between total length and PFAA load were investigated, as were differences in PFAA accumulation between sexes. No correlations were seen between crocodile size, nor were there sex-related differences. Spatial differences were examined and significant differences were observed in samples collected from the different sites (p < 0.05). Flag Boshielo Dam had the highest PFOS measurements, with a median concentration of 50.3 ng/g wet mass, when compared to the other sites (median concentrations at other sites below 14.0 ng/g wet mass). This suggests a point source of PFOS in this area. PMID:27038902

  11. Spatial and temporal trends of perfluorinated compounds in Beluga Whales (Delphinapterus leucas) from Alaska.

    PubMed

    Reiner, Jessica L; O'Connell, Steven G; Moors, Amanda J; Kucklick, John R; Becker, Paul R; Keller, Jennifer M

    2011-10-01

    Wildlife from remote locations have been shown to bioaccumulate perfluorinated compounds (PFCs) in their tissues. Twelve PFCs, consisting of perfluorinated carboxylic (PFCA) and sulfonic (PFSA) acids as well as the perfluorooctane sulfonate (PFOS) precursor perfluorooctane sulfonamide (PFOSA), were measured in livers of 68 beluga whales (Delphinapterus leucas) collected from two subpopulations, Cook Inlet and eastern Chukchi Sea, in Alaska between 1989 and 2006. PFOS and PFOSA were the dominant compounds measured in both beluga stock populations, with overall median concentrations of 10.8 ng/g and 22.8 ng/g, respectively. Long-chain perfluorocarboxylates, PFCAs (9 to 14 carbons), were detected in more than 80% of the samples. Perfluoroundecanoic acid (PFUnA) and perfluorotridecanoic acid (PFTriA) made up a large percentage of the PFCAs measured with median concentrations of 8.49 ng/g and 4.38 ng/g, respectively. To compare differences in location, year, sex, and length, backward stepwise multiple regression models of the individual and total PFC concentrations were used. Spatially, the Cook Inlet belugas had higher concentrations of most PFCAs and PFOS (p < 0.05); however, these belugas had a lower median concentration of PFOSA when compared to belugas from the eastern Chukchi Sea (p < 0.05). Temporal trends indicated most PFCAs, PFHxS, PFOS, and PFOSA concentrations increased from 1989 to 2006 (p < 0.05). Males had significantly higher concentrations of PFTriA, ΣPFCA, and PFOS (p < 0.05). Perfluorononanic acid (PFNA) and PFOS showed a significant decrease in concentration with increasing animal length (p < 0.05). These observations suggest the accumulation of PFCs in belugas is influenced by year, location, sex, and length. PMID:21309595

  12. Multimodal Plasmonics in Fused Colloidal Networks

    PubMed Central

    Teulle, Alexandre; Bosman, Michel; Girard, Christian; Gurunatha, Kargal L.; Li, Mei; Mann, Stephen; Dujardin, Erik

    2014-01-01

    Harnessing the optical properties of noble metals down to the nanometer-scale is a key step towards fast and low-dissipative information processing. At the 10-nm length scale, metal crystallinity and patterning as well as probing of surface plasmon (SP) properties must be controlled with a challenging high level of precision. Here, we demonstrate that ultimate lateral confinement and delocalization of SP modes are simultaneously achieved in extended self-assembled networks comprising linear chains of partially fused gold nanoparticles. The spectral and spatial distributions of the SP modes associated with the colloidal superstructures are evidenced by performing monochromated electron energy loss spectroscopy with a nanometer-sized electron probe. We prepare the metallic bead strings by electron beam-induced interparticle fusion of nanoparticle networks. The fused superstructures retain the native morphology and crystallinity but develop very low energy SP modes that are capable of supporting long range and spectrally tunable propagation in nanoscale waveguides. PMID:25344783

  13. Multimodal plasmonics in fused colloidal networks.

    PubMed

    Teulle, Alexandre; Bosman, Michel; Girard, Christian; Gurunatha, Kargal L; Li, Mei; Mann, Stephen; Dujardin, Erik

    2015-01-01

    Harnessing the optical properties of noble metals down to the nanometre scale is a key step towards fast and low-dissipative information processing. At the 10-nm length scale, metal crystallinity and patterning as well as probing of surface plasmon properties must be controlled with a challenging high level of precision. Here, we demonstrate that ultimate lateral confinement and delocalization of surface plasmon modes are simultaneously achieved in extended self-assembled networks comprising linear chains of partially fused gold nanoparticles. The spectral and spatial distributions of the surface plasmon modes associated with the colloidal superstructures are evidenced by performing monochromated electron energy-loss spectroscopy with a nanometre-sized electron probe. We prepare the metallic bead strings by electron-beam-induced interparticle fusion of nanoparticle networks. The fused superstructures retain the native morphology and crystallinity but develop very low-energy surface plasmon modes that are capable of supporting long-range and spectrally tunable propagation in nanoscale waveguides.

  14. 30 CFR 57.12036 - Fuse removal or replacement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fuse removal or replacement. 57.12036 Section 57.12036 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Electricity Surface and Underground § 57.12036 Fuse removal or replacement. Fuses shall not be removed...

  15. 30 CFR 56.12036 - Fuse removal or replacement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fuse removal or replacement. 56.12036 Section 56.12036 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... § 56.12036 Fuse removal or replacement. Fuses shall not be removed or replaced by hand in an...

  16. 49 CFR 173.184 - Highway or rail fusee.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... effects for signaling purposes. The composition of the fusee must be such that the fusee will not ignite... consecutive hours. (b) Fusees (highway and railway) must be packaged in steel (1A2), aluminum (1B2) or other metal (1N2) drums, steel (3A2) or aluminum (3B2) jerricans, steel (4A), aluminum (4B) or other metal...

  17. 49 CFR 173.184 - Highway or rail fusee.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... effects for signaling purposes. The composition of the fusee must be such that the fusee will not ignite... consecutive hours. (b) Fusees (highway and railway) must be packaged in steel (1A2), aluminum (1B2) or other metal (1N2) drums, steel (3A2) or aluminum (3B2) jerricans, steel (4A), aluminum (4B) or other metal...

  18. Thermal fuse for high-temperature batteries

    DOEpatents

    Jungst, Rudolph G.; Armijo, James R.; Frear, Darrel R.

    2000-01-01

    A thermal fuse, preferably for a high-temperature battery, comprising leads and a body therebetween having a melting point between approximately 400.degree. C. and 500.degree. C. The body is preferably an alloy of Ag--Mg, Ag--Sb, Al--Ge, Au--In, Bi--Te, Cd--Sb, Cu--Mg, In--Sb, Mg--Pb, Pb--Pd, Sb--Zn, Sn--Te, or Mg--Al.

  19. PENILE AGENESIS WITH CROSSED FUSED RENAL ECTOPIA.

    PubMed

    Derbew, Milliard; Ketema, Elbet

    2015-04-01

    Penile agenesis is one of the rarest urogenital anomalies with only less than 100 cases reported worldwide so far. Only 3 cases have been reported from Africa and to our knowledge none has been reported from our country Ethiopia. Viability depends on associated anomalies. Urogenital anomalies are the most common associated ones accounting for 54% of cases. This case report is unusual presentation, which is the first reported case of penile agenesis associated with left to right, crossed fused renal ectopia.

  20. Fusing maps with photos from mobile devices

    NASA Astrophysics Data System (ADS)

    Carlotto, Mark J.

    2014-06-01

    A method for fusing imagery from mobile devices with map data in real time is described. A camera model for iOS devices equipped with a camera, GPS, and compass is developed. The parameters of the camera model are determined from information supplied by the device's on board sensors. The camera model projects photo and video data into the ground plane so they can be combined and exploited with map data.

  1. 1,3-Dipolar cycloadditions of azomethine imines.

    PubMed

    Nájera, Carmen; Sansano, José M; Yus, Miguel

    2015-08-28

    Azomethine imines are considered 1,3-dipoles of the aza-allyl type which are transient intermediates and should be generated in situ but can also be stable and isolable compounds. They react with electron-rich and electron-poor olefins as well as with acetylenic compounds and allenoates mainly by a [3 + 2] cycloaddition but they can also take part in [3 + 3], [4 + 3], [3 + 2 + 2] and [5 + 3] with different dipolarophiles. These 1,3-dipolar cycloadditions (1,3-DC) can be performed not only under thermal or microwave conditions but also using metallo- and organocatalytic systems. In recent years enantiocatalyzed 1,3-dipolar cycloadditions have been extensively considered and applied to the synthesis of a great variety of dinitrogenated heterocycles with biological activity. Acyclic azomethine imines derived from mono and disubstituted hydrazones could be generated by prototropy under heating or by using Lewis or Brønsted acids to give, after [3 + 2] cycloadditions, pyrazolidines and pyrazolines. Cyclic azomethine imines, incorporating a C-N bond in a ring, such as isoquinolinium imides are the most widely used dipoles in normal and inverse-electron demand 1,3-DC allowing the synthesis of tetrahydro-, dihydro- and unsaturated pyrazolo[1,5-a]isoquinolines in racemic and enantioenriched forms with interesting biological activity. Pyridinium and quinolinium imides give the corresponding pyrazolopyridines and indazolo[3,2-a]isoquinolines, respectively. In the case of cyclic azomethine imines with an N-N bond incorporated into a ring, N-alkylidene-3-oxo-pyrazolidinium ylides are the most popular stable and isolated dipoles able to form dinitrogen-fused saturated and unsaturated pyrazolopyrazolones as racemic or enantiomerically enriched compounds present in many pharmaceuticals, agrochemicals and other useful chemicals.

  2. 1,3-Dipolar cycloadditions of azomethine imines.

    PubMed

    Nájera, Carmen; Sansano, José M; Yus, Miguel

    2015-08-28

    Azomethine imines are considered 1,3-dipoles of the aza-allyl type which are transient intermediates and should be generated in situ but can also be stable and isolable compounds. They react with electron-rich and electron-poor olefins as well as with acetylenic compounds and allenoates mainly by a [3 + 2] cycloaddition but they can also take part in [3 + 3], [4 + 3], [3 + 2 + 2] and [5 + 3] with different dipolarophiles. These 1,3-dipolar cycloadditions (1,3-DC) can be performed not only under thermal or microwave conditions but also using metallo- and organocatalytic systems. In recent years enantiocatalyzed 1,3-dipolar cycloadditions have been extensively considered and applied to the synthesis of a great variety of dinitrogenated heterocycles with biological activity. Acyclic azomethine imines derived from mono and disubstituted hydrazones could be generated by prototropy under heating or by using Lewis or Brønsted acids to give, after [3 + 2] cycloadditions, pyrazolidines and pyrazolines. Cyclic azomethine imines, incorporating a C-N bond in a ring, such as isoquinolinium imides are the most widely used dipoles in normal and inverse-electron demand 1,3-DC allowing the synthesis of tetrahydro-, dihydro- and unsaturated pyrazolo[1,5-a]isoquinolines in racemic and enantioenriched forms with interesting biological activity. Pyridinium and quinolinium imides give the corresponding pyrazolopyridines and indazolo[3,2-a]isoquinolines, respectively. In the case of cyclic azomethine imines with an N-N bond incorporated into a ring, N-alkylidene-3-oxo-pyrazolidinium ylides are the most popular stable and isolated dipoles able to form dinitrogen-fused saturated and unsaturated pyrazolopyrazolones as racemic or enantiomerically enriched compounds present in many pharmaceuticals, agrochemicals and other useful chemicals. PMID:26140443

  3. Outbursts In Symbiotic Binaries (FUSE 2000)

    NASA Technical Reports Server (NTRS)

    Kenyon, Scott J.; Sonneborn, George (Technical Monitor)

    2002-01-01

    During the past year, we made good progress on analysis of FUSE observations of the symbiotic binary Z And. For background, Z And is a binary system composed of a red giant and a hot component of unknown status. The orbital period is roughly 750 days. The hot component undergoes large-scale eruptions every 10-20 yr. An outburst began several years ago, triggering this FUSE opportunity. First, we obtained an excellent set of ground-based optical data in support, of the FUSE observations. We used FAST, a high throughput low resolution spectrograph on the 1.5-m telescope at Mt. Hopkins, Arizona. A 300 g/ mm grating blazed at 4750 A, a 3 in. slit, and a thinned Loral 512 x 2688 CCD gave us spectra covering 3800-7500 A at a resolution of 6 A. The wavelength solution for each spectrum has a probable error of +/- 0.5 A or better. Most of the resulting spectra have moderate signal-to-noise, S/.N approx. greater than 30 per pixel. The time coverage for these spectra is excellent. Typically, we acquired spectra every 1-2 nights during dark runs at Mt. Hopkins. These data cover most of the rise and all of the decline of the recent outburst. The spectra show a wealth of emission lines, including H I, He I, He II, [Fe V11], and the Raman scattering bands at 6830 A and 7088 A. The Raman bands and other high ionization features vary considerably throughout the outburst. These features will enable us to correlate variations in the FUSE spectra with variations in the optical spectra. Second, we began an analysis of FUSE spectra of Z And. We have carefully examined the spectra, identifying real features and defects. We have identified and measured fluxes for all strong emission lines, including the O VI doublet at 1032 A and 1038 A. These and several other strong emission lines display pronounced P Cygni absorption components indicative of outgrowing gas. We will attempt to correlate these velocities with similar profiles observed on optical spectra. The line velocities - together

  4. FUSE Observations of Comet C/2001 Q4 (NEAT)

    NASA Astrophysics Data System (ADS)

    Feldman, P. D.; Weaver, H. A.; Christian, D.; Combi, M. R.; Krasnopolsky, V.; Lisse, C. M.; Mumma, M. J.; Shemansky, D. E.; Stern, S. A.

    2004-11-01

    We report observations of comet C/2001 Q4 (NEAT) with the Far Ultraviolet Spectroscopic Explorer (FUSE) beginning 00:40 UT on 2004 April 24. This was the first moving target observation made by FUSE since the failure of two reaction wheels in December 2001. Spectra were obtained in the 905--1180 Å range at 0.3 Å spectral resolution using the 30'' × 30'' aperture and closely resemble the spectra of three comets observed in 2001 and reported previously. The principal features are the (0,0) bands of the CO Birge-Hopfield systems, atomic lines of \\ion{O}{1} and \\ion{H}{1}, and three lines of the H2 Lyman pumped by solar Lyman-β fluorescence. The CO C - X (0,0) band showed a nearly sinusoidal variation over the 27 hr observation interval with a period of 17.0 hr and a peak to minimum ratio of 1.56. The derived average CO production rate is Q(CO) = 8 × 1027 molecules s-1 which is about 4% that of H2O based on concurrent HST/STIS observations of OH emission. As in the previous observations, only upper limits are found for emission from \\ion{Ar}{1} and N2. A relatively strong feature near 1031.8 Å is most likely the H2 Werner (1,1) Q3 line pumped by solar \\ion{O}{6} and \\ion{N}{3}, as the corresponding lines in the (1,3) and (1,4) bands are also present. There may be evidence for weak \\ion{O}{6} emission at 1031.9 Å, in the wing of the H2 line, and at 1037.6 Å. The roughly two dozen other emissions that were not identified in the earlier spectra are also present in C/2001 Q4 at comparable strength to those in comet C/2001 A2 (LINEAR). As C/2001 A2 had a comparable water production rate to that of C/2001 Q4 at the time of observation, the source(s) of these emissions may be ubiquitous in comets. This work is based on data obtained by the NASA-CNES-CSA FUSE mission operated by The Johns Hopkins University. Financial support was partly provided by NASA contract NAS5-32985.

  5. Large work function shift of gold induced by a novel perfluorinated azobenzene-based self-assembled monolayer.

    PubMed

    Crivillers, Núria; Osella, Silvio; Van Dyck, Colin; Lazzerini, Giovanni M; Cornil, David; Liscio, Andrea; Di Stasio, Francesco; Mian, Shabbir; Fenwick, Oliver; Reinders, Federica; Neuburger, Markus; Treossi, Emanuele; Mayor, Marcel; Palermo, Vincenzo; Cacialli, Franco; Cornil, Jérôme; Samorì, Paolo

    2013-01-18

    Tune it with light! Self-assembled monolayers on gold based on a chemisorbed novel azobenzene derivative with a perfluorinated terminal phenyl ring are prepared. The modified substrate shows a significant work function increase compared to the bare metal. The photo-conversion between trans and cis isomers chemisorbed on the surface shows great perspectives for being an accessible route to tune the gold properties by means of light.

  6. Perfluorinated chemicals: Differential toxicity, inhibition of aromatase activity and alteration of cellular lipids in human placental cells

    SciTech Connect

    Gorrochategui, Eva; Pérez-Albaladejo, Elisabet; Casas, Josefina; Lacorte, Sílvia; Porte, Cinta

    2014-06-01

    The cytotoxicity of eight perfluorinated chemicals (PFCs), namely, perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorododecanoic acid (PFDoA), perfluorobutanesulfonate (PFBS), perfluorohexanesulfonate (PFHxS) and perfluorooctanesulfonate (PFOS) was assessed in the human placental choriocarcinoma cell line JEG-3. Only the long chain PFCs – PFOS, PFDoA, PFNA, PFOA – showed significant cytotoxicity in JEG-3 cells with EC50 values in the range of 107 to 647 μM. The observed cytotoxicity was to some extent related to a higher uptake of the longer chain PFCs by cells (PFDoA > PFOS ≫ PFNA > PFOA > PFHxA). Moreover, this work evidences a high potential of PFOS, PFOA and PFBS to act as aromatase inhibitors in placental cells with IC50s in the range of 57–80 μM, the inhibitory effect of PFBS being particularly important despite the rather low uptake of the compound by cells. Finally, exposure of JEG-3 cells to a mixture of the eight PFCs (0.6 μM each) led to a relative increase (up to 3.4-fold) of several lipid classes, including phosphatidylcholines (PCs), plasmalogen PC and lyso plasmalogen PC, which suggests an interference of PFCs with membrane lipids. Overall, this work highlights the ability of the PFC mixture to alter cellular lipid pattern at concentrations well below those that generate toxicity, and the potential of the short chain PFBS, often considered a safe substitute of PFOS, to significantly inhibit aromatase activity in placental cells. - Highlights: • Eight perfluorinated chemicals of different chain lengths have been selected. • Long chain ones – PFOS, PFDoA, PFNA, PFOA – were cytotoxic in placenta cells. • The uptake of long chain perfluorinated chemicals by cells was comparatively higher. • PFOS, PFOA and the short chain PFBS significantly inhibited aromatase activity. • A mixture of perfluorinated chemicals significantly altered placenta cell

  7. Discharge of perfluorinated compounds from rivers and their influence on the coastal seas of Hyogo prefecture, Japan.

    PubMed

    Takemine, Shusuke; Matsumura, Chisato; Yamamoto, Katsuya; Suzuki, Motoharu; Tsurukawa, Masahiro; Imaishi, Hiromasa; Nakano, Takeshi; Kondo, Akira

    2014-01-01

    The aim of this study was to investigate 12 perfluorinated compounds (PFCs) including perfluorinated carboxylates (C4-C12) and perfluorinated alkyl sulfonates (C4, C6, and C8) in river and seawater samples to determine contamination levels in the aquatic environment of Hyogo prefecture, Japan. High levels of perfluorohexanoic acid (PFHxA; 2300-16,000 ng/L) were detected in the Samondogawa River at Tatsumi Bridge downstream of a PFC production facility; this location also had the highest mass flow rate of PFCs (3900-29,000 kg/y). Widespread contamination of coastal waters was confirmed with PFHxA as the dominant compound. Perfluorooctanoic acid was also prevalent in coastal waters. The concentration of PFHxA in coastal seawater and the distance from the mouth of the Samondogawa River were inversely related. This discharge of high concentrations of PFHxA from the Samondogawa River may have affected concentrations of PFCs in Osaka Bay.

  8. Optical Performance Modeling of FUSE Telescope Mirror

    NASA Technical Reports Server (NTRS)

    Saha, Timo T.; Ohl, Raymond G.; Friedman, Scott D.; Moos, H. Warren

    2000-01-01

    We describe the Metrology Data Processor (METDAT), the Optical Surface Analysis Code (OSAC), and their application to the image evaluation of the Far Ultraviolet Spectroscopic Explorer (FUSE) mirrors. The FUSE instrument - designed and developed by the Johns Hopkins University and launched in June 1999 is an astrophysics satellite which provides high resolution spectra (lambda/Delta(lambda) = 20,000 - 25,000) in the wavelength region from 90.5 to 118.7 nm The FUSE instrument is comprised of four co-aligned, normal incidence, off-axis parabolic mirrors, four Rowland circle spectrograph channels with holographic gratings, and delay line microchannel plate detectors. The OSAC code provides a comprehensive analysis of optical system performance, including the effects of optical surface misalignments, low spatial frequency deformations described by discrete polynomial terms, mid- and high-spatial frequency deformations (surface roughness), and diffraction due to the finite size of the aperture. Both normal incidence (traditionally infrared, visible, and near ultraviolet mirror systems) and grazing incidence (x-ray mirror systems) systems can be analyzed. The code also properly accounts for reflectance losses on the mirror surfaces. Low frequency surface errors are described in OSAC by using Zernike polynomials for normal incidence mirrors and Legendre-Fourier polynomials for grazing incidence mirrors. The scatter analysis of the mirror is based on scalar scatter theory. The program accepts simple autocovariance (ACV) function models or power spectral density (PSD) models derived from mirror surface metrology data as input to the scatter calculation. The end product of the program is a user-defined pixel array containing the system Point Spread Function (PSF). The METDAT routine is used in conjunction with the OSAC program. This code reads in laboratory metrology data in a normalized format. The code then fits the data using Zernike polynomials for normal incidence

  9. FUSE Observations of Luminous Blue Variables

    NASA Astrophysics Data System (ADS)

    Iping, R. C.; Sonneborn, G.

    2001-12-01

    P-Cygni, AG Carinae, S-Doradus and Eta Carinae were observed with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. FUSE covers the spectral range 905 to 1187 Angstroms at a resolution of 0.05 Angstroms. In this paper we explore in what way the LBV's are similar and in what way they are different. For Eta Car the observed flux at 1160 A, is 4E-12 erg/cm2/s/A. This is 20X larger than observed by STIS/E140M at the same wavelength through a 0.2"x0.2" aperture. The flux level declines toward the Lyman limit where converging molecular and atomic hydrogen features completely blanket the spectrum. The shape of the spectrum shortward of 1110 Angstroms is dominated by strong absorption bands of interstellar molecular hydrogen. In addition to many strong interstellar atomic species, the spectrum contains several prominent P-Cygni features, including C III 1175, S IV 1063-73, Si III 1113, and N I 1134. The lines are broad with unsaturated absorption troughs, implying that the wind is patchy and/or only partly covers the UV emitting surface. The wind absorption extends to -1000 km/s. The large far ultraviolet flux levels at 1150-1180 A, relative to those observed by HST/STIS, imply that the observed far-UV spectrum is formed in an extended 1-2 arcsec diameter UV scattering envelope. The far-UV spectra of P Cygni and AG Carinae are very similar and indicate a cooler atmosphere than Eta Car and S Dor. There is very good agreement between the FUSE spectrum of P Cygni and a model atmosphere computed by Hillier with his code CMFGEN. This work has been supported in part by NASA grants NAG5-8631 to Catholic University of America and NAS5-32985 to Johns Hopkins University.

  10. Quartz/fused silica chip carriers

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The primary objective of this research and development effort was to develop monolithic microwave integrated circuit (MMIC) packaging which will operate efficiently at millimeter-wave frequencies. The packages incorporated fused silica as the substrate material which was selected due to its favorable electrical properties and potential performance improvement over more conventional materials for Ka-band operation. The first step towards meeting this objective is to develop a package that meets standard mechanical and thermal requirements using fused silica and to be compatible with semiconductor devices operating up to at least 44 GHz. The second step is to modify the package design and add multilayer and multicavity capacity to allow for application specific integrated circuits (ASIC's) to control multiple phase shifters. The final step is to adapt the package design to a phased array module with integral radiating elements. The first task was a continuation of the SBIR Phase 1 work. Phase 1 identified fused silica as a viable substrate material by demonstrating various plating, machining, and adhesion properties. In Phase 2 Task 1, a package was designed and fabricated to validate these findings. Task 2 was to take the next step in packaging and fabricate a multilayer, multichip module (MCM). This package is the predecessor to the phased array module and demonstrates the ability to via fill, circuit print, laminate, and to form vertical interconnects. The final task was to build a phased array module. The radiating elements were to be incorporated into the package instead of connecting to it with wire or ribbon bonds.

  11. Fused silica mirror development for SIRTF

    NASA Technical Reports Server (NTRS)

    Barnes, W. P., Jr.

    1983-01-01

    An advanced design, lightweight, fuse-quartz mirror of sandwich construction was evaluated for optical figure performance at cryogenic temperatures. A low temperature shroud was constructed with an integral mirror mount and interface to a cryostat for use in a vacuum chamber. The mirror was tested to 13 K. Cryogenic distortion of the mirror was measured interferometrically. Separate interferometry of the chamber window during the test permitted subtraction of the small window distortions from the data. Results indicate that the imaging performance of helium cooled, infrared telescopes will be improved using this type of mirror without correction of cryogenic distortion of the primary mirror.

  12. Phomopchalasins A and B, Two Cytochalasans with Polycyclic-Fused Skeletons from the Endophytic Fungus Phomopsis sp. shj2.

    PubMed

    Yan, Bing-Chao; Wang, Wei-Guang; Hu, Dong-Bao; Sun, Xiang; Kong, Ling-Mei; Li, Xiao-Nian; Du, Xue; Luo, Shi-Hong; Liu, Yan; Li, Yan; Sun, Han-Dong; Pu, Jian-Xin

    2016-03-01

    Phomopchalasins A (1) and B (2), two novel cytochalasans with unprecedented carbon skeletons, and phomopchalasin C (3), containing a rare hydroperoxyl motif, were obtained from the endophytic fungus Phomopsis sp. shj2, which was first isolated from the Isodon eriocalyx var. laxiflora. Their structures were elucidated by extensive spectroscopic analyses, electronic circular dichroism (ECD) calculation, and X-ray crystallographic analysis. Notably, 1 possessed an unprecedented 5/6/5/8-fused tetracyclic ring system, and 2 featured a novel 5/6/6/7/5-fused pentacyclic skeleton. The cytotoxic, anti-inflammatory, and antimigratory activities of 1-3 were evaluated in vitro. PMID:26881701

  13. Perfluorinated compounds in surface waters and WWTPs in Shenyang, China: mass flows and source analysis.

    PubMed

    Sun, Hongwen; Li, Fasong; Zhang, Tao; Zhang, Xianzhong; He, Na; Song, Qi; Zhao, Lijie; Sun, Lina; Sun, Tieheng

    2011-10-01

    Concentrations of 10 perfluorinated chemicals (PFCs) were investigated in the Hun River (HR), four canals, ten lakes, and influents and effluents from four main municipal wastewater treatment plants (WWTPs) in Shenyang, China. Mass flows of four main PFCs were calculated to elucidate the contribution from different sections of the HR. Overall, perfluorooctanoic acid (PFOA) and perfluorohexanoic acid (PFHxA) were the major PFCs in the HR, with ranges of 2.68-9.13 ng/L, and 2.12-11.3 ng/L, respectively, while perfluorooctane sulfonate (PFOS) was detected at lower levels, ranging from 0.40 to 3.32 ng/L. The PFC concentrations in the HR increased after the river passes through two cities (Shenyang and Fushun), indicating cities are an important contributor for PFCs. Mass flow analysis in the HR revealed that PFC mass flows from Fushun are 1.65-5.50 kg/year for C6-C8 perfluorinated acids (PFCAs) and 1.29 kg/year for PFOS, while Shenyang contributed 2.83-5.18 kg C6-C8 PFCAs/year, and 3.65 kg PFOS/year. The concentrations of PFCs in four urban canals were higher than those in the HR, with the maximum total PFCs of 240 ng/L. PFOA and PFOS showed different trends along these canals, suggesting different sources for the two PFCs. Total PFCs in ten lakes from Shenyang were at low levels, with the greatest concentration (56.2 ng/L) detected in a heavily industrialized area. The PFC levels in WWTP effluents were higher than those in surface waters with concentrations ranging from 18.4 to 41.1 ng/L for PFOA, and 1.69-3.85 ng/L for PFOS. Similar PFC profiles between effluents from WWTPs and urban surface waters were found. These results indicate that WWTPs are an important PFC source in surface water. Finally, we found that the composition profiles of PFCs in surface waters were similar to those in tap water, but not consistent with those in adult blood from Shenyang. The calculation on total daily intake of PFOS by adults from Shenyang showed that the contribution of

  14. Fate of perfluorinated carboxylates and sulfonates during snowmelt within an urban watershed.

    PubMed

    Meyer, Torsten; De Silva, Amila O; Spencer, Christine; Wania, Frank

    2011-10-01

    The transport dynamics of perfluorinated carboxylic acids and sulfonates during snowmelt in the highly urbanized Highland Creek watershed in Toronto, Canada was investigated by analyzing river water, bulk snow, and groundwater, sampled in February and March 2010, by means of liquid chromatography-tandem mass spectrometry. Perfluorohexanoate, perfluorooctanoate, and perfluorooctane sulfonate were dominant in river water, with concentrations of 4.0-14 ng·L(-1), 2.2-7.9 ng·L(-1), and 2.1-6.5 ng·L(-1), respectively. Relatively high levels of perfluorohexanoate may be related to the recent partial replacement in various consumer products of perfluorooctyl substances with shorter-chained perfluorinated compounds (PFCs). Highest PFC concentrations were found within the more urbanized part of the drainage area, suggestive of residential, industrial, and/or traffic-related sources. The riverine flux of PFCs increased during the snowmelt period, but only approximately one-fifth of the increased flux can be attributed to PFCs present in the snowpack, mostly because concentration in snow are generally quite low compared to those in river water. The remainder of the increased flux must be due to the mobilization of PFCs by the high flow conditions prevalent during snowmelt. Run-off behavior was clearly dependent on perfluoroalkyl chain length: Dilution with relatively clean snowmelt water caused a drop in the river water concentrations of short-chain PFCs at high flow during early melting. This prevented an early concentration peak of those water-soluble PFCs within the stream, as could have been expected in response to their early release from a melting snowpack. Instead, concentrations of particle-associated long-chain PFCs in creek water peaked early in the melt, presumably because high flow mobilized contaminated particles from impervious surfaces in the more urbanized areas of the watershed. The ability to enter the subsurface and deeper groundwater aquifers increased

  15. CO2 laser welding fused silica.

    SciTech Connect

    Reed, Scott T.; MacCallum, Danny O'Neill; Knorovsky, Gerald Albert

    2005-08-01

    The feasibility of laser welding of fused silica (aka quartz) has been demonstrated recently by others. An application requiring hermetic sealing of a thin, pressure-bearing quartz diaphragm to a thicker frame led us to explore this technique. We found that laser welding techniques normally used for metallic parts caused scorching and uneven melting. Contrary to standard practices (near focus, high travel speed, high power density), successful welds in fused silica required a broad heat source applied over a large area under a slow rotation to gradually heat the glass through the annealing, softening and finally working temperatures. Furthermore, good mechanical contact between the parts to be joined played an even more important role in this process than in typical metallic joints. A 50 W CO2 laser with 4 f.l. ZnSe2 lens and rotary head was used to weld 0.425 OD, 0.006-0.010 thick, disks to 0.500 OD tubing with 0.125 walls. Several joint geometries and beam orientations were investigated. Temperature profiles were measured and compared to an FEM thermal model. We will discuss the effects of laser power, travel speed, number of passes, joint geometry and part thicknesses on achieving hermeticity and cosmetically-acceptable joints.

  16. Electrostatic Discharge Properties of Fused Silica Coatings

    NASA Astrophysics Data System (ADS)

    Andersen, Allen; Sim, Charles; Dennison, J. R.

    2012-10-01

    The electric field value at which electrostatic discharge (ESD) occurs was studied for thin coatings of fused silica (highly disordered SiO2/SiOx) on conductive substrates, such as those encountered as optical coatings and in Si microfabrication. The electrostatic breakdown field was determined using an increasing voltage, while monitoring the leakage current. A simple parallel-plate capacitor geometry was used, under medium vacuum and at temperatures down to ˜150 K using a liquid N2 reservoir. The breakdown field, pre-breakdown arcing and I-V curves for fused silica samples are compared for ˜60 nm and ˜80 μm thick, room and low temperature, and untreated and irradiated samples. Unlike typical I-V results for polymeric insulators, the thin film silica samples did not exhibit pre-breakdown arcing, displayed transitional resistivity after initial breakdown, and in many cases showed evidence of a second discontinuity in the I-V curves. This diversity of observed discharge phenomena is discussed in terms of breakdown modes and defect generation on a microscopic scale.

  17. Fused Reality for Enhanced Flight Test Capabilities

    NASA Technical Reports Server (NTRS)

    Bachelder, Ed; Klyde, David

    2011-01-01

    The feasibility of using Fused Reality-based simulation technology to enhance flight test capabilities has been investigated. In terms of relevancy to piloted evaluation, there remains no substitute for actual flight tests, even when considering the fidelity and effectiveness of modern ground-based simulators. In addition to real-world cueing (vestibular, visual, aural, environmental, etc.), flight tests provide subtle but key intangibles that cannot be duplicated in a ground-based simulator. There is, however, a cost to be paid for the benefits of flight in terms of budget, mission complexity, and safety, including the need for ground and control-room personnel, additional aircraft, etc. A Fused Reality(tm) (FR) Flight system was developed that allows a virtual environment to be integrated with the test aircraft so that tasks such as aerial refueling, formation flying, or approach and landing can be accomplished without additional aircraft resources or the risk of operating in close proximity to the ground or other aircraft. Furthermore, the dynamic motions of the simulated objects can be directly correlated with the responses of the test aircraft. The FR Flight system will allow real-time observation of, and manual interaction with, the cockpit environment that serves as a frame for the virtual out-the-window scene.

  18. Fusing Symbolic and Numerical Diagnostic Computations

    NASA Technical Reports Server (NTRS)

    James, Mark

    2007-01-01

    X-2000 Anomaly Detection Language denotes a developmental computing language, and the software that establishes and utilizes the language, for fusing two diagnostic computer programs, one implementing a numerical analysis method, the other implementing a symbolic analysis method into a unified event-based decision analysis software system for realtime detection of events (e.g., failures) in a spacecraft, aircraft, or other complex engineering system. The numerical analysis method is performed by beacon-based exception analysis for multi-missions (BEAMs), which has been discussed in several previous NASA Tech Briefs articles. The symbolic analysis method is, more specifically, an artificial-intelligence method of the knowledge-based, inference engine type, and its implementation is exemplified by the Spacecraft Health Inference Engine (SHINE) software. The goal in developing the capability to fuse numerical and symbolic diagnostic components is to increase the depth of analysis beyond that previously attainable, thereby increasing the degree of confidence in the computed results. In practical terms, the sought improvement is to enable detection of all or most events, with no or few false alarms.

  19. FUSE Observations of K--M Stars

    NASA Astrophysics Data System (ADS)

    Ake, T. B.; Dupree, A. K.; Linsky, J. L.; Harper, G. M.; Young, P. R.

    2000-12-01

    As part of the FUSE PI program, a representative sample of cool stars is being surveyed in the LWRS (30 x 30 arcsec) aperture. We report on recent observations of three late-type stars, AU Mic (HD 197481, M0 Ve), β Gem (HD 62509, K0 IIIb), and α Ori (HD 39801, M1-2 Ia--Iab). AU Mic and β Gem show strong emission lines of O VI 1032/1037 and C III 977/1176 and weaker lines of C II, N II, N III, S IV, Si III, Si IV, and perhaps Fe III. AU Mic has evidence of He II and S III emission, and β Gem shows S I emission. Differences are seen in line ratios and line profiles between these stars. In α Ori, these features are very weak or non-existent, and Fe II fluorescent lines in the 1100-1150 Å region, pumped by H I Lyman α , are present. Several emission lines are still unidentified in all spectra. Prospects for future cool star observations will be discussed. This work is based on data obtained for the Guaranteed Time Team by the NASA-CNES-CSA FUSE mission operated by the Johns Hopkins University. Financial support to U. S. participants has been provided by NASA contract NAS5-32985.

  20. Spectral fusing Gabor domain optical coherence microscopy.

    PubMed

    Meemon, Panomsak; Widjaja, Joewono; Rolland, Jannick P

    2016-02-01

    Gabor domain optical coherence microscopy (GD-OCM) is one of many variations of optical coherence tomography (OCT) techniques that aims for invariant high resolution across a 3D field of view by utilizing the ability to dynamically refocus the imaging optics in the sample arm. GD-OCM acquires multiple cross-sectional images at different focus positions of the objective lens, and then fuses them to obtain an invariant high-resolution 3D image of the sample, which comes with the intrinsic drawback of a longer processing time as compared to conventional Fourier domain OCT. Here, we report on an alternative Gabor fusing algorithm, the spectral-fusion technique, which directly processes each acquired spectrum and combines them prior to the Fourier transformation to obtain a depth profile. The implementation of the spectral-fusion algorithm is presented and its performance is compared to that of the prior GD-OCM spatial-fusion approach. The spectral-fusion approach shows twice the speed of the spatial-fusion approach for a spectrum size of less than 2000 point sampling, which is a commonly used spectrum size in OCT imaging, including GD-OCM.

  1. 16 CFR 1.3 - Advice.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Advice. 1.3 Section 1.3 Commercial Practices FEDERAL TRADE COMMISSION ORGANIZATION, PROCEDURES AND RULES OF PRACTICE GENERAL PROCEDURES Industry Guidance Advisory Opinions § 1.3 Advice. (a) On the basis of the materials submitted, as well as any...

  2. 43 CFR 8365.1-3 - Vehicles.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Vehicles. 8365.1-3 Section 8365.1-3 Public... OF THE INTERIOR RECREATION PROGRAMS VISITOR SERVICES Rules of Conduct § 8365.1-3 Vehicles. (a) When operating a vehicle on the public lands, no person shall exceed posted speed limits, willfully...

  3. 50 CFR 1.3 - Service.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 1 2010-10-01 2010-10-01 false Service. 1.3 Section 1.3 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR GENERAL PROVISIONS DEFINITIONS § 1.3 Service. Service means the United States Fish and Wildlife Service, Department of the Interior....

  4. 5 CFR 1.3 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Definitions. 1.3 Section 1.3 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE RULES COVERAGE AND DEFINITIONS (RULE I) § 1.3 Definitions. As used in the rules in this subchapter: (a) Competitive service shall have the...

  5. 45 CFR 1216.1-3 - Policy.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 4 2012-10-01 2012-10-01 false Policy. 1216.1-3 Section 1216.1-3 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE NONDISPLACEMENT OF EMPLOYED WORKERS AND NONIMPAIRMENT OF CONTRACTS FOR SERVICE § 1216.1-3 Policy. (a)...

  6. 45 CFR 1216.1-3 - Policy.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 4 2013-10-01 2013-10-01 false Policy. 1216.1-3 Section 1216.1-3 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE NONDISPLACEMENT OF EMPLOYED WORKERS AND NONIMPAIRMENT OF CONTRACTS FOR SERVICE § 1216.1-3 Policy. (a)...

  7. Halting the fuse discharge propagation using optical fiber microwires.

    PubMed

    Rocha, A M; Fernandes, G; Domingues, F; Niehus, M; Pinto, A N; Facão, M; André, P S

    2012-09-10

    We report and analyze the halting of the fuse effect propagation in optical fiber microwires. The increase of the mode field diameter in the tapered region decreases the optical intensity resulting in the extinction of the fuse effect. This fiber element presents a low insertion loss and can be introduced in the optical network in order to protect the active equipment from the damage caused by the fuse effect.

  8. Modeling the hydrolysis of perfluorinated compounds containing carboxylic and phosphoric acid ester functions and sulfonamide groups.

    PubMed

    Rayne, Sierra; Forest, Kaya

    2010-01-01

    Temperature-dependent rate constants were estimated for the acid- and base-catalyzed and neutral hydrolysis reactions of perfluorinated telomer acrylates (FTAcrs) and phosphate esters (FTPEs), and the S(N)1 and S(N)2 hydrolysis reactions of fluorotelomer iodides (FTIs). Under some environmental conditions, hydrolysis of monomeric FTAcrs could be rapid (half-lives of several years in marine systems and as low as several days in some landfills) and represent a dominant portion of their overall degradation. Abiotic hydrolysis of monomeric FTAcrs may be a significant contributor to current environmental loadings of fluorotelomer alcohols (FTOHs) and perfluoroalkyl carboxylic acids (PFCAs). Polymeric FTAcrs are expected to be hydrolyzed more slowly, with estimated half-lives in soil and natural waters ranging between several centuries to several millenia absent additional surface area limitations on reactivity. Poor agreement was found between the limited experimental data on FTPE hydrolysis and computational estimates, requiring more detailed experimental data before any further modeling can occur on these compounds or their perfluoroalkyl sulfonamidoethanol phosphate ester (PFSamPE) analogs. FTIs are expected to have hydrolytic half-lives of about 130 days in most natural waters, suggesting they may be contributing to substantial FTOH and PFCA inputs in aquatic systems. Perfluoroalkyl sulfonamides (PFSams) appear unlikely to undergo abiotic hydrolysis at the S-N, C-S, or N-C linkages under environmentally relevant conditions, although potentially facile S-N hydrolysis via intramolecular catalysis by ethanol and acetic acid amide substituents warrants further investigation. PMID:20390888

  9. [Pollution fingerprints and sources of perfluorinated compounds in surface soil of different functional areas].

    PubMed

    Zhang, Hong; Zhao, Liang; He, Long; Chai, Zhi-Fang; Shen, Jin-Can; Yang, Bo

    2014-07-01

    In order to explore the effect of regional functions on the pollution fingerprints and levels of perfluorinated compounds (PFCs), principal components analysis was combined with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and solid phase extraction enrichment in this research to analyze the levels of 14 PFCs species in 76 surface soil samples, which were collected from 4 functional regions, namely parks, communities, crossroads and surroundings of factories, as well as the urban background of Shenzhen. The results showed that regional functions had significant effect on total PFCs (sigma PFCs), which ranked as the following: surroundings of factories (P < 0.001) > crossroads (P < 0.01) > communities (P < 0.05) > parks > urban background. The distribution of PFCs was in the order of medium- (P < 0.05) > long- > short-chain PFCs in surroundings of factories, communities and crossroads, while in the order of medium- approximately short- (P < 0.05) > long chain PFCs in crossroads. Over 81% of sigmaPFCs in the surface soil of Shenzhen could be attributed to the three principal components, represented by perfluorooctane sulfonate, perfluorooctane acid and perfluorotridecanoic acid, respectively. PFCs fingerprints were clearly shown in crossroads, as well as in surroundings of electroplating and paint factories.

  10. Distribution of perfluorinated compounds in Yellow-legged gull eggs (Larus michahellis) from the Iberian Peninsula.

    PubMed

    Vicente, Joana; Bertolero, Albert; Meyer, Johan; Viana, Paula; Lacorte, Silvia

    2012-02-01

    This study is aimed to evaluate the presence and distribution of Perfluorinated Compounds (PFCs) in Yellow-legged gull eggs (Larus michahellis) collected from 8 National or Natural Parks from the Iberian Peninsula. In each colony, 12 eggs were randomly collected and pooled from 3 areas of the colony and analyzed using liquid-solid extraction and liquid chromatography coupled to tandem mass spectrometry. Perfluorooctanate sulfonate (PFOS) was the only compound detected in the eggs and its presence was higher in the colonies situated in NE Iberian Peninsula due to the more industrial and mass urbanization in this area compared to the SW Mediterranean or Atlantic colonies. Accordingly, the Medes site, followed by the Ebro Delta and Columbretes, all situated in the NW Mediterranean coast, contained the highest PFOS levels (40.5-54.0ng/g-ww). In all other colonies, PFOS was detected at levels of 10.1-18.6ng/g-ww. Egg shell biometry was studied and it was found that the presence of PFOS did not affect the development of the egg.

  11. Mass Balance of Perfluorinated Alkyl Acids in a Pristine Boreal Catchment.

    PubMed

    Filipovic, Marko; Laudon, Hjalmar; McLachlan, Michael S; Berger, Urs

    2015-10-20

    Mass balances of ten individual perfluorinated alkyl acids (PFAAs) in two nested pristine catchments in Northern Sweden with different sizes and hydrological functions were assembled for 2011-2012. Concentrations of PFAAs in rain and snowmelt, as well as in streamwater at the outlet of the two watersheds were measured and used to calculate PFAA atmospheric inputs to and riverine outputs from the catchments. The results generally showed a great excess of PFAA inputs for both catchments over the whole study year. However, during the spring flood period, the inputs and outputs were within a factor of 2 for several PFAAs and the streamwater showed PFAA patterns resembling the patterns in rain (as opposed to snowmelt), suggesting that snowmelt water infiltrating the ground had displaced water from the previous summer. Comparison of PFAA mass balances between the two catchments further suggested that atmospheric inputs of short-chain (replacement) perfluoroalkyl carboxylic acids had increased in the years before sampling, while inputs of the legacy perfluorooctane sulfonic acid had decreased. Overall, the mass balances indicate that a considerable portion of the PFAAs deposited from the atmosphere are stored in soil and may be released to surface and marine water environments in the future.

  12. High performance liquid chromatography tandem mass spectrometry determination of perfluorinated acids in cow milk.

    PubMed

    Capriotti, Anna Laura; Cavaliere, Chiara; Cavazzini, Alberto; Foglia, Patrizia; Laganà, Aldo; Piovesana, Susy; Samperi, Roberto

    2013-12-01

    A new and sensitive liquid chromatography/electrospray-tandem mass spectrometric (LC/ESI-MS/MS) method for the determination of 12 perfluorinated compounds (PFCs) in cow milk is described. Milk samples were extracted with acetone and cleaned-up by a graphitized carbon black solid-phase extraction cartridge, optimizing the entire procedure by using a screening experimental design. LC/ESI-MS/MS was performed in negative ion mode using multiple reaction monitoring mode. The performance of the method was evaluated under the optimized conditions in terms of matrix effects, range of linearity, accuracy, and repeatability. For all compounds, linearity in matrix was observed in the range LOQ-10μgL(-1), and coefficients of determination R(2) ranged from 0.9982 to 0.9999. The analytical recoveries, relative to the isotopic internal standard, measured at 10 and 50ngL(-1) were in the range of 91-105%, with relative standard deviations below 6% and method detection limit, based on the blank value +3 times the standard deviation of the blank, ranged from 0.5 to 3ngL(-1). The final method developed was used to determine the concentration of PFCs in 15 retail milk samples. None of these compounds were detected in cow milk analyzed samples.

  13. Perfluorinated carboxylic acids in human breast milk from Spain and estimation of infant's daily intake.

    PubMed

    Motas Guzmàn, Miguel; Clementini, Chiara; Pérez-Cárceles, Maria Dolores; Jiménez Rejón, Sandra; Cascone, Aurora; Martellini, Tania; Guerranti, Cristiana; Cincinelli, Alessandra

    2016-02-15

    Human milk samples were collected from 67 mothers in 2014 at a Primary Care Centre in Murcia (Spain) and analyzed for perfluorinated carboxylic acids (PFCAs). Concentrations measured for perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA) and perfluorododecanoic acid (PFDoDA) ranged from

  14. C6-Perfluorinated Compounds: The New Greaseproofing Agents in Food Packaging.

    PubMed

    Rice, Penelope A

    2015-03-01

    Due to their oleophobic and hydrophobic properties and stability, perfluorinated compounds (PFCs) are used in many applications, particularly as greaseproofing agents for food contact. However, PFCs 8-carbons in length or greater (C8-PFCs) have raised concerns regarding environmental biopersistence, bioaccumulation in humans, and potent toxicity that have resulted in their gradual phase-out for food contact use. Industry has replaced C8-PFCs with shorter-chained C6-based greaseproofing agents, which are intended to have the same favorable physicochemical properties without the problematic toxicological effects in humans and wildlife. Compared with the large body of data available for C8 compounds, however, the available database on toxicity and exposure to the C6 compounds is fairly limited. This article summarizes the information in this database, focusing on aspects of human exposure and potential health risks associated with two types of C6 PFCs found in food packaging: perfluorohexanoic acid (PFHxA) and 6-2 fluorotelomer alcohol (C6-FTOH). PMID:26231240

  15. Contamination by perfluorinated compounds in water near waste recycling and disposal sites in Vietnam.

    PubMed

    Kim, Joon-Woo; Tue, Nguyen Minh; Isobe, Tomohiko; Misaki, Kentaro; Takahashi, Shin; Viet, Pham Hung; Tanabe, Shinsuke

    2013-04-01

    There are very few reports on the contamination by perfluorinated chemicals (PFCs) in the environment of developing countries, especially regarding their emission from waste recycling and disposal sites. This is the first study on the occurrence of a wide range of PFCs (17 compounds) in ambient water in Vietnam, including samples collected from a municipal dumping site (MD), an e-waste recycling site (ER), a battery recycling site (BR) and a rural control site. The highest PFC concentration was found in a leachate sample from MD (360 ng/L). The PFC concentrations in ER and BR (mean, 57 and 16 ng/L, respectively) were also significantly higher than those detected in the rural control site (mean, 9.4 ng/L), suggesting that municipal solid waste and waste electrical and electronic equipment are potential contamination sources of PFCs in Vietnam. In general, the most abundant PFCs were perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluoroundecanoic acid (PFUDA; <1.4-100, <1.2-100, and <0.5-20 ng/L, respectively). Interestingly, there were specific PFC profiles: perfluoroheptanoic acid and perfluorohexanoic acid (88 and 77 ng/L, respectively) were almost as abundant as PFOA in MD leachate (100 ng/L), whereas PFNA was prevalent in ER and BR (mean, 17 and 6.2 ng/L, respectively) and PFUDA was the most abundant in municipal wastewater (mean, 5.6 ng/L), indicating differences in PFC contents in different waste materials.

  16. Pine Needles for the Screening of Perfluorinated Alkylated Substances (PFASs) along Ski Tracks.

    PubMed

    Chropeňová, Mária; Karásková, Pavlína; Kallenborn, Roland; Gregušková, Eva Klemmová; Čupr, Pavel

    2016-09-01

    Perfluorinated alkylated substances (PFASs) are today considered persistent, toxic, and bioaccumulative contaminants. Perfluorooctansulfonate (PFOS) and perfluorooctanoic acid (PFOA) are currently listed as priority substances under the UNEP global convention for the regulation of POPs. A previous study reported higher levels of PFASs in pine needles near ski areas. Their application as stain repellents in modern outdoor clothes and in ski waxes is assumed to be a potential source. Pine trees (Pinus mugo in Slovakia and Pinus sylvestris in Norway) were chosen for sampling in ski resorts. Relative distributions, overall concentrations, trend estimates, elevation patterns, and distance from primary sources were assessed. PFOA was the predominant PFAS constituent in pine needles from Slovakia (8-93%). In Norway, the most-abundant PFAS was perfluorobutanoic acid (PFBA: 3-66%). A difference in product composition (particularly in ski waxes) and differences in Norwegian and Slovakian regulations are considered to be the primary reason for these differences. Open application of PFOA in industry and products has been banned in Norway since 2011. The replacement of PFOA with short-chain substitutes is thus considered the reason for the observed pattern differences in the analyzed pine needles. Regular monitoring and screening programs are recommended. PMID:27457263

  17. Chromosomal aneuploidies and DNA fragmentation of human spermatozoa from patients exposed to perfluorinated compounds.

    PubMed

    Governini, L; Guerranti, C; De Leo, V; Boschi, L; Luddi, A; Gori, M; Orvieto, R; Piomboni, P

    2015-11-01

    This study investigated chromosomal aneuploidies and DNA damage in spermatozoa from male patients contaminated by perfluorinated compounds (PFCs) in whole blood and seminal plasma. Sperm aneuploidy and diploidy rate for chromosomes 18, X and Y were evaluated by FISH; sperm DNA fragmentation was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling technique coupled to flow cytometry. Our results indicated that PFC contamination was present in 58% of subjects included in the study. A significant increase in alterations of sperm parameters was observed in PFC-positive subjects compared to PFC-negative subjects. As regards the sperm aneuploidy, both disomy and diploidy rates resulted significantly increased in subjects positive for PFC contamination compared to PFC-negative samples. In addition, sperm DNA fragmentation index resulted significantly increased in PFC-contaminated subjects compared to PFC-non-contaminated subjects, with a significant increased level of dimmer DNA fragmentation index. Our results clearly indicate that PFC contamination may detrimentally affect spermatogenesis, disturbing both meiotic segregation and DNA integrity. We could therefore suggest cautions to reduce or eliminate any contact with these compounds because the long-term effects of PFC accumulation in the body are not predictable.

  18. [Residue characteristics and distributions of perfluorinated compounds in surface seawater along Shenzhen coastline].

    PubMed

    Chen, Qing-Wu; Zhang, Hong; Chai, Zhi-Fang; Shen, Jin-Can; Yang, Bo

    2012-06-01

    In order to explore the residue characteristics and distributions of 15 perfluorinated compounds (PFCs) in 18 surface seawater samples along Shenzhen coastline, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) combined with solid phase extraction enrichment was applied in this research. The results indicated that residue level of PFCs in coastal surface seawater samples was significantly affected by human activities. Sigma PFCs residue levels in surface seawater from Shenzhen west coast, which locates below the estuary of Pearl River and Donghao River, are much higher than those from the east coast, which has low development and sparse population (P<0.05). Under natural conditions, sigma PFCs residue levels in coastal surface seawater samples from Shenzhen Bays are higher than those out of bays. The major residue species in surface seawater samples along Shenzhen coast were medium- and short-chain PFCs, including perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanoic acid and perfluoropentanoic acid. Their similar environmental behavior (P<0.05, P<0.01) is likely associated with the production process of PFCs-related products. Furthermore, cluster analysis results show that PFOS (R2 = 0.4092) level can be used as a representative parameter for evaluating PFCs contamination status in surface seawater along Shenzhen coast.

  19. Mass Balance of Perfluorinated Alkyl Acids in a Pristine Boreal Catchment.

    PubMed

    Filipovic, Marko; Laudon, Hjalmar; McLachlan, Michael S; Berger, Urs

    2015-10-20

    Mass balances of ten individual perfluorinated alkyl acids (PFAAs) in two nested pristine catchments in Northern Sweden with different sizes and hydrological functions were assembled for 2011-2012. Concentrations of PFAAs in rain and snowmelt, as well as in streamwater at the outlet of the two watersheds were measured and used to calculate PFAA atmospheric inputs to and riverine outputs from the catchments. The results generally showed a great excess of PFAA inputs for both catchments over the whole study year. However, during the spring flood period, the inputs and outputs were within a factor of 2 for several PFAAs and the streamwater showed PFAA patterns resembling the patterns in rain (as opposed to snowmelt), suggesting that snowmelt water infiltrating the ground had displaced water from the previous summer. Comparison of PFAA mass balances between the two catchments further suggested that atmospheric inputs of short-chain (replacement) perfluoroalkyl carboxylic acids had increased in the years before sampling, while inputs of the legacy perfluorooctane sulfonic acid had decreased. Overall, the mass balances indicate that a considerable portion of the PFAAs deposited from the atmosphere are stored in soil and may be released to surface and marine water environments in the future. PMID:26390224

  20. Perfluorinated acid isomer profiling in water and quantitative assessment of manufacturing source.

    PubMed

    Benskin, Jonathan P; Yeung, Leo W Y; Yamashita, Nobuyoshi; Taniyasu, Sachi; Lam, Paul K S; Martin, Jonathan W

    2010-12-01

    A method for isomer profiling of perfluorinated compounds (PFCs) in water was developed and applied to quantitatively assess the contributions from electrochemical (ECF) and telomer manufacturing processes around source regions of North America, Asia, and Europe. With the exception of 3 sites in Japan, over 80% of total perfluorooctanoate (PFOA, C(7)F(15)COO(-)) was from ECF, with the balance attributable to strictly linear (presumably telomer) manufacturing source(s). Comparing PFOA isomer profiles in samples from China, with PFOA obtained from a local Chinese manufacturer, indicated <3% difference in overall branched isomer content; thus, exclusive contribution from local ECF production cannot be ruled out. In Tokyo Bay, ECF, linear-telomer, and isopropyl-telomer sources contributed to 33%, 53%, and 14% of total PFOA, respectively. Perfluorooctane sulfonate (PFOS, C(8)F(17)SO(3)(-)) isomer profiles were enriched in branched content (i.e., >50% branched) in the Mississippi River but in all other locations were similar or only slightly enriched in branched content relative to historical ECF PFOS. Isomer profiles of other PFCs are also reported. Overall, these data suggest that, with the exception of Tokyo Bay, ECF manufacturing has contributed to the bulk of contamination around these source regions, but other sources are significant, and remote sites should be monitored.

  1. Biomonitoring and Elimination of Perfluorinated Compounds and Polychlorinated Biphenyls through Perspiration: Blood, Urine, and Sweat Study

    PubMed Central

    Genuis, Stephen J.; Beesoon, Sanjay; Birkholz, Detlef

    2013-01-01

    Perfluorinated compounds (PFCs) are man-made organofluorine chemicals manufactured and marketed for their stain-resistant properties. Polychlorinated biphenyls (PCBs) are anthropogenic organochlorine compounds previously used in various industrial and chemical applications prior to being banned in the Western world in the 1970s. Both PFCs and PCBs are persistent contaminants within the human organism and both have been linked to adverse health sequelae. Data is lacking on effective means to facilitate clearance of PFCs and PCBs from the body. Methods. Blood, urine, and sweat were collected from 20 individuals (10 healthy participants and 10 participants with assorted health problems) and analyzed for PFCs and PCBs using high performance liquid chromatography tandem mass spectrometry. Results. Some individual PCB congeners, but not all, were released into sweat at varying concentrations. None of the PFCs found in serum testing appeared to be excreted efficiently into perspiration. Conclusions. Induced perspiration may have some role in facilitating elimination of selected PCBs. Sweat analysis may be helpful in establishing the existence of some accrued PCBs in the human body. Sweating does not appear to facilitate clearance of accrued PFHxS (perfluorohexane sulfonate), PFOS (perfluorooctane sulfonate), or PFOA (perfluorooctanoic acid), the most common PFCs found in the human body. PMID:24083032

  2. Effect of resin type on the signal integrity of an embedded perfluorinated polymer optical fiber

    NASA Astrophysics Data System (ADS)

    Hamouda, Tamer; Peters, Kara; Seyam, Abdel-Fattah M.

    2012-05-01

    Polymer optical fibers (POF) hold many advantages for embedded sensing, such as their low cost, flexibility, high tensile strain limits and high fracture toughness. POF sensors may therefore be integrated into fiber reinforced composite structures for monitoring structural behavior. Since POFs do not require a protective coating, it is critical to verify that the resin system does not have a negative impact on the noise level or performance of POF sensors during composite manufacture. This study measured the effect of vinylester and epoxy resin systems on the signal loss of embedded perfluorinated, graded index POFs. Photon-counting optical time domain reflectometry (OTDR) was used to monitor the signal attenuation and backscattering level of the POFs throughout the resin curing cycle. Fourier transform infrared spectrometry (FTIR) and cross section analyses using scanning electronic microscope (SEM) images were also conducted to investigate whether the resin system caused chemical and physical changes of the POF. This study showed that vinylester resin caused a significant increase in the backscattering level of POF sensors and therefore induced high fiber signal losses. On the other hand, the POF treated with epoxy showed no change in backscattering level, indicating that no chemical or physical change had occurred to the POF.

  3. Prediction of aqueous solubility, vapor pressure and critical micelle concentration for aquatic partitioning of perfluorinated chemicals.

    PubMed

    Bhhatarai, Barun; Gramatica, Paola

    2011-10-01

    The majority of perfluorinated chemicals (PFCs) are of increasing risk to biota and environment due to their physicochemical stability, wide transport in the environment and difficulty in biodegradation. It is necessary to identify and prioritize these harmful PFCs and to characterize their physicochemical properties that govern the solubility, distribution and fate of these chemicals in an aquatic ecosystem. Therefore, available experimental data (10-35 compounds) of three important properties: aqueous solubility (AqS), vapor pressure (VP) and critical micelle concentration (CMC) on per- and polyfluorinated compounds were collected for quantitative structure-property relationship (QSPR) modeling. Simple and robust models based on theoretical molecular descriptors were developed and externally validated for predictivity. Model predictions on selected PFCs were compared with available experimental data and other published in silico predictions. The structural applicability domains (AD) of the models were verified on a bigger data set of 221 compounds. The predicted properties of the chemicals that are within the AD, are reliable, and they help to reduce the wide data gap that exists. Moreover, the predictions of AqS, VP, and CMC of most common PFCs were evaluated to understand the aquatic partitioning and to derive a relation with the available experimental data of bioconcentration factor (BCF).

  4. Association between perfluorinated compounds and pathological conditions in southern sea otters

    USGS Publications Warehouse

    Kannan, K.; Perrotta, E.; Thomas, N.J.

    2006-01-01

    Concentrations of four perfluorinated contaminants, including perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA), were measured in liver tissue from 80 adult female sea otters collected from the California coast during 1992a??2002. Concentrations of PFOS and PFOA were in the ranges of <1a??884 and <5a??147 ng/g, wet wt, respectively. Concentrations of PFOA in the livers of these sea otters were among the highest values reported for marine mammals to date. Liver tissue from 6 male sea otters also was analyzed and contained significantly higher concentrations of PFOS than did tissues from female otters. To examine the association between exposures and potential effects, concentrations of PFOS and PFOA were compared among the adult female otters that died from infectious diseases, noninfectious causes, and from apparent emaciation. Concentrations of both PFOA and PFOS were significantly higher in sea otters in the infectious disease category than in the noninfectious category. Concentrations of PFOS and PFOA were not significantly different between noninfectious and emaciated otters, suggesting that the poor nutritive (body) status of emaciated otters did not affect the concentrations of perfluorochemicals in livers. Concentrations of PFOA increased significantly from 1992 to 2002, whereas PFOS concentrations increased from 1992 to 1998 and then decreased after 2000. Significant association between infectious diseases and elevated concentrations of PFOS/PFOA in the livers of sea otters is a cause for concern and suggests the need for further studies.

  5. Trophic magnification of poly- and perfluorinated compounds in a subtropical food web.

    PubMed

    Loi, Eva I H; Yeung, Leo W Y; Taniyasu, Sachi; Lam, Paul K S; Kannan, Kurunthachalam; Yamashita, Nobuyoshi

    2011-07-01

    Perfluorinated compounds (PFCs) are known to biomagnify in temperate and Arctic food webs, but little is known about their behavior in subtropical systems. The environmental distribution and biomagnification of PFCs, extractable organic fluorine (EOF), and total fluorine were investigated in a subtropical food web. Surface water, sediment, phytoplankton, zooplankton, gastropods, worms, shrimps, fishes, and waterbirds collected in the Mai Po Marshes Nature Reserve in Hong Kong were analyzed. Trophic magnification was observed for perfluorooctanesulfonate (PFOS), perfluorodecanoate (PFDA), perfluoroundecanoate (PFUnDA), and perfluorododecanoate (PFDoDA) in this food web. Risk assessment results for PFOS, PFDA, and perfluorooctanoate (PFOA) suggest that current PFC concentrations in waterbird livers are unlikely to pose adverse biological effects to waterbirds. All hazard ratio (HR) values reported for PFOS and PFOA are less than one, which suggests that the detected levels will not cause any immediate health effects to the Hong Kong population through the consumption of shrimps and fishes. However, only 10-12% of the EOF in the shrimp samples was comprised of known PFCs, indicating the need for further investigation to identify unknown fluorinated compounds in wildlife.

  6. [Influence of tap water treatment on perfluorinated compounds residue in the dissolved phase].

    PubMed

    Zhang, Hong; Chen, Qing-wu; Wang, Xin-xuan; Chai, Zhi-fang; Shen, Jin-can; Yang, Bo; Liu, Guo-qing

    2013-09-01

    To study the perfluorinated compounds (PFCs) residues through water treatments including flocculation, sedimentation, sand filtration, ozonation with activated carbon and chlorination, as well as the seasonal variation of PFCs in the raw water of waterworks, 13 PFCs species in the dissolved phase of raw water, finished water, as well as the water samples after flocculation, sedimentation, sand filtration, and ozonation with activated carbon filtration were measured by the high performance liquid chromatography-tandem mass spectrometry combined with solid phase extraction. Results indicated that sigma PFCs residue in water was higher in spring and summer than that in fall and winter. The vast majority of PFCs in samples were of short and medium chains (C < or = 10), and perfluorooctane sulfonate was the most typical residue species. Among the five water treatment stages, sedimentation, sand filtration and ozonation with activated carbon filtration can remove PFCs, while flocculation and chlorination significantly raise the levels of short- (C < or = 6) and medium-chain (10 > or = C > or = 7) PFCs, respectively, causing sigma PFCs increase in finished water by 10%-44% compared to raw water. However, the PFCs residues in finished water are still far below their limit values, posing no threat against human health.

  7. Flux of perfluorinated chemicals through wet deposition in Japan, the United States, and several other countries.

    PubMed

    Kwok, Karen Y; Taniyasu, Sachi; Yeung, Leo W Y; Murphy, Margaret B; Lam, Paul K S; Horii, Yuichi; Kannan, Kurunthachalam; Petrick, Gert; Sinha, Ravindra K; Yamashita, Nobuyoshi

    2010-09-15

    The widespread distribution of perfluorinated chemicals (PFCs) in different environmental matrices has prompted concern about the sources, fate, and transport of these classes of chemicals. PFCs are present in the atmosphere, but only a few studies have investigated their occurrence in precipitation. In this study, concentrations of 20 PFCs, including C3-C5 short-chain PFCs, were quantified using HPLC-MS/MS in precipitation samples from Japan (n = 31), the United States (n = 12), China (n = 5), India (n = 2), and France (n = 2). Among the PFCs measured, perfluoropropanoic acid (PFPrA) was detected in all of the precipitation samples. Average total PFC concentrations ranged from 1.40 to 18.1 ng/L for the seven cities studied. The greatest total PFC concentrations were detected in Tsukuba, Japan, whereas the lowest concentrations were detected in Patna, India. PFPrA, perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) were found to be the dominant PFCs in Japanese and U.S. precipitation samples. No observable seasonal trend was found in precipitation samples from two locations in Japan. Annual fluxes of PFCs were estimated for Japan and the U.S. and the evidence for precipitation as an effective scavenger of PFCs in the atmosphere is reported.

  8. Nano- and micro-fabrication of perfluorinated polymers using quantum beam technology

    NASA Astrophysics Data System (ADS)

    Miyoshi, Nozomi; Oshima, Akihiro; Urakawa, Tatsuya; Fukutake, Naoyuki; Nagai, Hiroyuki; Gowa, Tomoko; Takasawa, Yuya; Takahashi, Tomohiro; Numata, Yukari; Katoh, Takanori; Katoh, Etsuko; Tagawa, Seiichi; Washio, Masakazu

    2011-02-01

    Micro- and nano-fabrication researches of various perfluorinated polymers carried out recently both by synchrotron radiation (SR) direct photo-etching and by focused ion beam (FIB) direct mask less etching are reviewed. After the irradiation, the etching depth of the fabricated samples has been evaluated by optical microscope and scanning electron microscope. SR-induced surface modifications were studied by solid-state 19F nuclear magnetic resonance (NMR) spectroscopy and differential scanning calorimeter (DSC) analysis. It was found that the etching rate of FEP at 140 °C was highest and that of PTFE and PFA at 140 °C was lower in the SR etching. It was found that crosslinking reactions were induced by SR irradiation at the region within about 50 μm from the irradiated surface. FIB mask less etching showed very attractive features for nano-scale fabrications. The aspect ratio for crosslinked PTFE (RX-PTFE) reached 390. In addition, the nano-scale controlled structures with high aspect and quality of RX-PTFE were obtained without solid debris.

  9. Effect of effluent organic matter on the adsorption of perfluorinated compounds onto activated carbon.

    PubMed

    Yu, Jing; Lv, Lu; Lan, Pei; Zhang, Shujuan; Pan, Bingcai; Zhang, Weiming

    2012-07-30

    Effect of effluent organic matter (EfOM) on the adsorption of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) onto powdered activated carbon (PAC) was quantitatively investigated at environmentally relevant concentration levels. The adsorption of both perfluorinated compounds (PFCs) onto PAC followed pseudo-second order kinetics and fitted the Freundlich model well under the given conditions. Intraparticle diffusion was found to be the rate-controlling step in the PFC adsorption process onto PAC in the absence and presence of EfOM. The presence of EfOM, either in PFC-EfOM simultaneous adsorption onto fresh PAC or in PFC adsorption onto EfOM-preloaded PAC, significantly reduced the adsorption capacities and sorption rates of PFCs. The pH of zero point of charge was found to be 7.5 for fresh PAC and 4.2 for EfOM-preloaded PAC, suggesting that the adsorbed EfOM imparted a negative charge on PAC surface. The effect of molecular weight distribution of EfOM on the adsorption of PFCs was investigated with two EfOM fractions obtained by ultrafiltration. The low-molecular-weight compounds (<1kDa) were found to be the major contributors to the significant reduction in PFC adsorption capacity, while large-molecular-weight compounds (>30kDa) had much less effect on PFC adsorption capacity. PMID:22609392

  10. An Integrated Modeling Approach for Describing Fate and Transport of Perfluorinated Compounds (PFCs) in Estuarine Reservoir

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Nguyen Viet, T.; Wang, X.; Chen, H.; Gin, K. Y. H.

    2014-12-01

    The fate and transport processes of emerging contaminants in aquatic ecosystems are complex, which are not only determined by their own properties but also influenced by the environmental setting, physical, chemical and biological processes. A 3D-emerging contaminant model has been developed based on Delft3D water quality model and coupled with a hydrodynamic model and a catchment-scale 1D- hydrological and hydraulic model to study the possible fate and transport mechanisms of perfluorinated compounds (PFCs) in Marina Reservoir in Singapore. The main processes in the contaminant model include partitioning (among detritus, dissolved organic matter and phytoplankton), settling, resuspension and degradation. We used the integrated model to quantify the distribution of the total PFCs and two major components, namely perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) in the water, sediments and organisms in the reservoir. The model yielded good agreement with the field measurements when evaluated based on the datasets in 2009 and 2010 as well as recent observations in 2013 and 2014. Our results elucidate that the model can be a useful tool to characterize the occurrence, sources, sinks and trends of PFCs both in the water column and in the sediments in the reservoir. Thisapproach provides a better understanding of mechanisms that influence the fate and transport of emerging contaminants and lays down a framework for future experiments to further explore how the dominant environmental factors change towards mitigation of emerging contaminants in the reservoirs.

  11. Root uptake and translocation of perfluorinated alkyl acids by three hydroponically grown crops.

    PubMed

    Felizeter, Sebastian; McLachlan, Michael S; De Voogt, Pim

    2014-04-16

    Tomato, cabbage, and zucchini plants were grown hydroponically in a greenhouse. They were exposed to 14 perfluorinated alkyl acids (PFAAs) at four different concentrations via the nutrient solution. At maturity the plants were harvested, and the roots, stems, leaves, twigs (where applicable), and edible parts (tomatoes, cabbage head, zucchinis) were analyzed separately. Uptake and transfer factors were calculated for all plant parts to assess PFAA translocation and distribution within the plants. Root concentration factors were highest for long-chain PFAAs (>C11) in all three plant species, but these chemicals were not found in the edible parts. All other PFAAs were present in all above-ground plant parts, with transpiration stream concentration factors (TSCFs) of 0.05-0.25. These PFAAs are taken up with the transpiration stream and accumulate primarily in the leaves. Although some systematic differences were observed, overall their uptake from nutrient solution to roots and their further distribution within the plants were similar between plant species and among PFAAs.

  12. Root uptake and translocation of perfluorinated alkyl acids by three hydroponically grown crops.

    PubMed

    Felizeter, Sebastian; McLachlan, Michael S; De Voogt, Pim

    2014-04-16

    Tomato, cabbage, and zucchini plants were grown hydroponically in a greenhouse. They were exposed to 14 perfluorinated alkyl acids (PFAAs) at four different concentrations via the nutrient solution. At maturity the plants were harvested, and the roots, stems, leaves, twigs (where applicable), and edible parts (tomatoes, cabbage head, zucchinis) were analyzed separately. Uptake and transfer factors were calculated for all plant parts to assess PFAA translocation and distribution within the plants. Root concentration factors were highest for long-chain PFAAs (>C11) in all three plant species, but these chemicals were not found in the edible parts. All other PFAAs were present in all above-ground plant parts, with transpiration stream concentration factors (TSCFs) of 0.05-0.25. These PFAAs are taken up with the transpiration stream and accumulate primarily in the leaves. Although some systematic differences were observed, overall their uptake from nutrient solution to roots and their further distribution within the plants were similar between plant species and among PFAAs. PMID:24646206

  13. Pine Needles for the Screening of Perfluorinated Alkylated Substances (PFASs) along Ski Tracks.

    PubMed

    Chropeňová, Mária; Karásková, Pavlína; Kallenborn, Roland; Gregušková, Eva Klemmová; Čupr, Pavel

    2016-09-01

    Perfluorinated alkylated substances (PFASs) are today considered persistent, toxic, and bioaccumulative contaminants. Perfluorooctansulfonate (PFOS) and perfluorooctanoic acid (PFOA) are currently listed as priority substances under the UNEP global convention for the regulation of POPs. A previous study reported higher levels of PFASs in pine needles near ski areas. Their application as stain repellents in modern outdoor clothes and in ski waxes is assumed to be a potential source. Pine trees (Pinus mugo in Slovakia and Pinus sylvestris in Norway) were chosen for sampling in ski resorts. Relative distributions, overall concentrations, trend estimates, elevation patterns, and distance from primary sources were assessed. PFOA was the predominant PFAS constituent in pine needles from Slovakia (8-93%). In Norway, the most-abundant PFAS was perfluorobutanoic acid (PFBA: 3-66%). A difference in product composition (particularly in ski waxes) and differences in Norwegian and Slovakian regulations are considered to be the primary reason for these differences. Open application of PFOA in industry and products has been banned in Norway since 2011. The replacement of PFOA with short-chain substitutes is thus considered the reason for the observed pattern differences in the analyzed pine needles. Regular monitoring and screening programs are recommended.

  14. C6-Perfluorinated Compounds: The New Greaseproofing Agents in Food Packaging.

    PubMed

    Rice, Penelope A

    2015-03-01

    Due to their oleophobic and hydrophobic properties and stability, perfluorinated compounds (PFCs) are used in many applications, particularly as greaseproofing agents for food contact. However, PFCs 8-carbons in length or greater (C8-PFCs) have raised concerns regarding environmental biopersistence, bioaccumulation in humans, and potent toxicity that have resulted in their gradual phase-out for food contact use. Industry has replaced C8-PFCs with shorter-chained C6-based greaseproofing agents, which are intended to have the same favorable physicochemical properties without the problematic toxicological effects in humans and wildlife. Compared with the large body of data available for C8 compounds, however, the available database on toxicity and exposure to the C6 compounds is fairly limited. This article summarizes the information in this database, focusing on aspects of human exposure and potential health risks associated with two types of C6 PFCs found in food packaging: perfluorohexanoic acid (PFHxA) and 6-2 fluorotelomer alcohol (C6-FTOH).

  15. Understanding Potential Exposure Sources of Perfluorinated Carboxylic Acids in the Workplace

    PubMed Central

    Kaiser, Mary A.; Dawson, Barbara J.; Barton, Catherine A.; Botelho, Miguel A.

    2010-01-01

    This paper integrates perspectives from analytical chemistry, environmental engineering, and industrial hygiene to better understand how workers may be exposed to perfluorinated carboxylic acids when handling them in the workplace in order to identify appropriate exposure controls. Due to the dramatic difference in physical properties of the protonated acid form and the anionic form, this family of chemicals provides unique industrial hygiene challenges. Workplace monitoring, experimental data, and modeling results were used to ascertain the most probable workplace exposure sources and transport mechanisms for perfluorooctanoic acid (PFOA) and its ammonium salt (APFO). PFOA is biopersistent and its measurement in the blood has been used to assess human exposure since it integrates exposure from all routes of entry. Monitoring suggests that inhalation of airborne material may be an important exposure route. Transport studies indicated that, under low pH conditions, PFOA, the undissociated (acid) species, actively partitions from water into air. In addition, solid-phase PFOA and APFO may also sublime into the air. Modeling studies determined that contributions from surface sublimation and loss from low pH aqueous solutions can be significant potential sources of workplace exposure. These findings suggest that keeping surfaces clean, preventing accumulation of material in unventilated areas, removing solids from waste trenches and sumps, and maintaining neutral pH in sumps can lower workplace exposures. PMID:20974675

  16. Workers at CCAS attach solar panel to FUSE satellite.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At Hangar AE, Cape Canaveral Air Station (CCAS), workers check the installation of a solar panel on NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. FUSE was developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., to investigate the origin and evolution of the lightest elements in the universe - hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum. FUSE is targeted for launch June 23 from Launch Pad 17A, CCAS, aboard a Boeing Delta II rocket.

  17. Workers at CCAS attach solar panel to FUSE satellite.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Workers at Hangar AE, Cape Canaveral Air Station (CCAS), get ready to move the scaffolding from around NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. FUSE is targeted for launch June 23 from Launch Pad 17A, CCAS, aboard a Boeing Delta II rocket. FUSE was developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., to investigate the origin and evolution of the lightest elements in the universe - hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum.

  18. Workers at CCAS attach solar panel to FUSE satellite.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At Hangar AE, Cape Canaveral Air Station (CCAS), workers move a solar panel toward NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite before attaching it. FUSE was developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., to investigate the origin and evolution of the lightest elements in the universe - hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum. FUSE is targeted for launch June 23 from Launch Pad 17A, CCAS, aboard a Boeing Delta II rocket.

  19. Workers at CCAS attach solar panel to FUSE satellite.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At Hangar AE, Cape Canaveral Air Station (CCAS), workers attach a solar panel to NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. FUSE was developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., to investigate the origin and evolution of the lightest elements in the universe - hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum. FUSE is targeted for launch June 23 from Launch Pad 17A, CCAS, aboard a Boeing Delta II rocket.

  20. Boeing Delta II rocket for FUSE launch arrives at CCAS

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At Launch Pad 17A, Cape Canaveral Air Station (CCAS), the first stage of a Boeing Delta II rocket is moved into the tower. The rocket is targeted to launch NASA's Far Ultraviolet Spectroscopic Explorer (FUSE), developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md. FUSE will investigate the origin and evolution of the lightest elements in the universe, hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum. FUSE is scheduled to be launched June 23 at CCAS.

  1. Fast-acting self-healing metallic fuse.

    NASA Technical Reports Server (NTRS)

    Schwartz, F. C.; Renton, C. A.; Rabinovici, B.

    1971-01-01

    Description of a fast-acting nonmechanical self-healing mercury fuse capable of protecting a high current circuit or device from overcurrent fault damages. Basically the self-healing fuse consists of two enclosed mercury reservoirs connected by a fine capillary tube filled with mercury that serves as the fusing element. It is pointed out that a better understanding of the energy conversion process involved in the operation of the device could help explore other device configurations (such as a tapering geometry and use of magnetic field to drive the arc into the fuse wall on inductive loads, etc.) and thus extend the range of capabilities for this type of protective device.

  2. Laser Damage Precursors in Fused Silica

    SciTech Connect

    Miller, P; Suratwala, T; Bude, J; Laurence, T A; Shen, N; Steele, W A; Feit, M; Menapace, J; Wong, L

    2009-11-11

    There is a longstanding, and largely unexplained, correlation between the laser damage susceptibility of optical components and both the surface quality of the optics, and the presence of near surface fractures in an optic. In the present work, a combination of acid leaching, acid etching, and confocal time resolved photoluminescence (CTP) microscopy has been used to study laser damage initiation at indentation sites. The combination of localized polishing and variations in indentation loads allows one to isolate and characterize the laser damage susceptibility of densified, plastically flowed and fractured fused silica. The present results suggest that: (1) laser damage initiation and growth are strongly correlated with fracture surfaces, while densified and plastically flowed material is relatively benign, and (2) fracture events result in the formation of an electronically defective rich surface layer which promotes energy transfer from the optical beam to the glass matrix.

  3. Understanding error generation in fused deposition modeling

    NASA Astrophysics Data System (ADS)

    Bochmann, Lennart; Bayley, Cindy; Helu, Moneer; Transchel, Robert; Wegener, Konrad; Dornfeld, David

    2015-03-01

    Additive manufacturing offers completely new possibilities for the manufacturing of parts. The advantages of flexibility and convenience of additive manufacturing have had a significant impact on many industries, and optimizing part quality is crucial for expanding its utilization. This research aims to determine the sources of imprecision in fused deposition modeling (FDM). Process errors in terms of surface quality, accuracy and precision are identified and quantified, and an error-budget approach is used to characterize errors of the machine tool. It was determined that accuracy and precision in the y direction (0.08-0.30 mm) are generally greater than in the x direction (0.12-0.62 mm) and the z direction (0.21-0.57 mm). Furthermore, accuracy and precision tend to decrease at increasing axis positions. The results of this work can be used to identify possible process improvements in the design and control of FDM technology.

  4. Mid-IR fused fiber couplers

    NASA Astrophysics Data System (ADS)

    Stevens, G.; Woodbridge, T.

    2016-03-01

    We present results from our recent efforts on developing single-mode fused couplers in ZBLAN fibre. We have developed a custom fusion workstation for working with lower melting temperature fibres, such as ZBLAN and chalcogenide fibres. Our workstation uses a precisely controlled electrical heater designed to operate at temperatures between 100 - 250°C as our heat source. The heated region of the fibers was also placed in an inert atmosphere to avoid the formation of microcrystal inclusions during fusion. We firstly developed a process for pulling adiabatic tapers in 6/125 μm ZBLAN fibre. The tapers were measured actively during manufacture using a 2000 nm source. The process was automated so that the heater temperature and motor speed automatically adjusted to pull the taper at constant tension. This process was then further developed so that we could fuse and draw two parallel 6/125 μm ZBLAN fibres, forming a single-mode coupler. Low ratio couplers (1-10%) that could be used as power monitors were manufactured that had an excess loss of 0.76 dB. We have also manufactured 50/50 splitters and wavelength division multiplexers (WDMs). However, the excess loss of these devices was typically 2 - 3 dB. The increased losses were due to localised necking and surface defects forming as the tapers were pulled further to achieve a greater coupling ratio. Initial experiments with chalcogenide fibre have shown that our process can be readily adapted for chalcogenide fibres. A 5% coupler with 1.5 dB insertion loss was manufactured using commercial of the shelf (COTS) fibres.

  5. FUSE Observations of Luminous Cool Stars

    NASA Astrophysics Data System (ADS)

    Dupree, A. K.; Young, P. R.; Ake, T. B.

    2000-12-01

    Luminous cool stars can address the evolution of magnetic activity and the dynamics of stellar winds and mass loss. The region of yellow supergiants in the HR diagram contains stars of intermediate mass both with coronas and those possessing a hot outer atmosphere in the presence of a strong wind (the ``hybrid'' stars). These hybrid objects hold particular significance for evolution studies because they represent the physically important connection between solar-like stars (with coronas and fast winds of low-mass loss rate) and the cool supergiant stars (Alpha Ori-like) with cool outer atmospheres and massive winds. The Far Ultraviolet Spectroscopic Explorer (FUSE) measured the chromospheric and transition region emissions of the bright G2 Ib supergiant Beta Draconis (HD 159181) on 9 May 2000. Two exposures through the large aperture totaled 7695 s and were obtained in all channels covering the region λ λ 912-1180. Emission from chromospheric and transition region ions (C III, O VI, Si III, S IV, S VI) is detected along with a number of low ion stages. Profiles of strong lines are asymmetric suggesting the presence of a wind. A short exposure (3260 s) of Alpha Aquarii (HD 209750), a hybrid supergiant also of spectral type G2 Ib was obtained June 29, 2000. Dynamics of the atmospheres can be inferred from line profiles. The atmospheric temperature distribution, densities, and scale sizes can be evaluated from line fluxes to characterize the differences between a coronal star and a hybrid supergiant. FUSE is a NASA Origins mission operated by The Johns Hopkins University. Funding for this research is provided through NASA Contract NAS-532985.

  6. Manufacturing miniature Langmuir probes by fusing platinum bond wires

    NASA Astrophysics Data System (ADS)

    Berglund, Martin; Sturesson, Peter; Thornell, Greger; Persson, Anders

    2015-10-01

    This paper reports on a novel method for manufacturing microscopic Langmuir probes with spherical tips from platinum bond wires by fusing for plasma characterization in microplasma sources. Here, the resulting endpoints, formed by droplets on the ends of a fused wire, are intended to act as spherical Langmuir probes. For studying the fusing behavior, bond wires were wedge bonded over a 2 mm wide slit, to emulate the final application, and fused with different voltages and currents. For electrical isolation, a set of wires were coated with a 4 μm thick layer of Parylene before they were fused. After fusing, the gap size, as well as the shape and area of the ends of the remaining stubs were measured. The yield of the process was also investigated, and the fusing event was studied using a high-speed camera for analyzing its dynamics. Four characteristic tip shapes were observed: spherical, folded, serpentine shaped and semi-spherical. The stub length leveled out at  ˜400 μm as the fusing power increased. The fusing of the coated wires required a higher power to yield a spherical shape. Finally, a Parylene coated bond wire was integrated into a stripline split-ring resonator (SSRR) microplasma source, and was fused to form two Langmuir probes with spherical endpoints. These probes were used for measuring the I-V characteristics of a plasma generated by the SSRR. In a voltage range between  -60 V and 60 V, the fused stubs exhibited the expected behavior of spherical Langmuir probes, and will be considered for further integration.

  7. π-Stacked structure of thiadiazolo-fused benzotriazinyl radical: Crystal structure and magnetic properties

    NASA Astrophysics Data System (ADS)

    Miura, Youhei; Yoshioka, Naoki

    2015-04-01

    A novel benzotriazinyl radical with a 2,1,3-thiadiazolo fused ring (1,3-diphenyl-1,2-dihydro-[1,2,5]thiadiazolo[3‧,4‧:3,4]benzo[1,2-e]-1,2,4-triazine-2-yl; NSNBT) was prepared and characterized by ESR measurement, cyclic voltammetry, and X-ray crystallographic analysis. By a detailed study of bond lengths and angles, it was found that the molecular structure of NSNBT borrows characteristics both from 2,1,3-benzothiadiazole and from the unsubstituted benzotriazinyl radical, and the central phenyl ring presents a phenanthrene-type bond alternation. Molecules were shown to be arranged in a π-stacked columnar structure, with columns connected to each other through sulfur-sulfur interactions in the crystal. It exhibited strong antiferromagnetic interactions (J/kB = -434 K) derived from its dimer structure.

  8. Structure-dependent binding and activation of perfluorinated compounds on human peroxisome proliferator-activated receptor γ

    SciTech Connect

    Zhang, Lianying; Ren, Xiao-Min; Wan, Bin; Guo, Liang-Hong

    2014-09-15

    Perfluorinated compounds (PFCs) have been shown to disrupt lipid metabolism and even induce cancer in rodents through activation of peroxisome proliferator-activated receptors (PPARs). Lines of evidence showed that PPARα was activated by PFCs. However, the information on the binding interactions between PPARγ and PFCs and subsequent alteration of PPARγ activity is still limited and sometimes inconsistent. In the present study, in vitro binding of 16 PFCs to human PPARγ ligand binding domain (hPPARγ-LBD) and their activity on the receptor in cells were investigated. The results showed that the binding affinity was strongly dependent on their carbon number and functional group. For the eleven perfluorinated carboxylic acids (PFCAs), the binding affinity increased with their carbon number from 4 to 11, and then decreased slightly. The binding affinity of the three perfluorinated sulfonic acids (PFSAs) was stronger than their PFCA counterparts. No binding was detected for the two fluorotelomer alcohols (FTOHs). Circular dichroim spectroscopy showed that PFC binding induced distinctive structural change of the receptor. In dual luciferase reporter assays using transiently transfected Hep G2 cells, PFCs acted as hPPARγ agonists, and their potency correlated with their binding affinity with hPPARγ-LBD. Molecular docking showed that PFCs with different chain length bind with the receptor in different geometry, which may contribute to their differences in binding affinity and transcriptional activity. - Highlights: • Binding affinity between PFCs and PPARγ was evaluated for the first time. • The binding strength was dependent on fluorinated carbon chain and functional group. • PFC binding induced distinctive structural change of the receptor. • PFCs could act as hPPARγ agonists in Hep G2 cells.

  9. [Residue Concentration and Distribution Characteristics of Perfluorinated Compounds in Surface Water from Qiantang River in Hangzhou Section].

    PubMed

    Zhang, Ming; Tang, Fang-liang; Yu, Ya-yun; Xu, Jian-fen; Li, Hua; Wu, Min-hua; Zhang, Wei; Pan, Jian-yang

    2015-12-01

    This study studied the pollution characteristics of perfluorinated compounds (PFCs) in Qiantang River in Hangzhou section (QR). Surface water samples, collected in July 2014 and January 2015 from 14 sites in QR were analyzed for 16 PFCs. All samples were prepared by solid-phase extraction with Oasis WAX cartridges and analyzed using the ultra performance liquid chromatography interfaced to tandem mass spectrometry ( UPLC-MS/MS). The results showed that 8 medium-and short-chain PFCs including C₄ and C₈ perfluorinated sulfonates (PFSAs) and C₄-C₉ perfluorinated carboxylic acids (PFCAs) were detected in the surface waters. The total concentrations of PFCs ranged from 0.98 to 609 ng · L⁻¹, while perfluorooctanoic acid (PFOA) dominated, with range of 0.59-538 ng L⁻¹, and perfluorooctane sulfonate (PFOS) was detected at lower levels, ranging from 0 to 2.48 ng · L⁻¹. The spatial distribution of PFCs varied, and the pollutant concentrations at the sampling sites located in upstream of the river such as Lanjiangkou and Jiangjunyan were relatively high, PFCs concentration showed a decreasing trend from the upstream to the downstream. According to the ratio of feature components, PFCs in surface water of QR originated largely from the input of direct sewage emissions. Taken together, the PFCs pollution was highly correlated with the upstream of Qiantang River valley's industry distribution, and most of the mass load in the investigated river was attributed to upstream running water with a minor influence from the wastewater discharges along the river basin. Overall, the results presented here indicated that greater attention should be given to the contamination of PFCs, especially for PFOA in water body of QR.

  10. [Residue Concentration and Distribution Characteristics of Perfluorinated Compounds in Surface Water from Qiantang River in Hangzhou Section].

    PubMed

    Zhang, Ming; Tang, Fang-liang; Yu, Ya-yun; Xu, Jian-fen; Li, Hua; Wu, Min-hua; Zhang, Wei; Pan, Jian-yang

    2015-12-01

    This study studied the pollution characteristics of perfluorinated compounds (PFCs) in Qiantang River in Hangzhou section (QR). Surface water samples, collected in July 2014 and January 2015 from 14 sites in QR were analyzed for 16 PFCs. All samples were prepared by solid-phase extraction with Oasis WAX cartridges and analyzed using the ultra performance liquid chromatography interfaced to tandem mass spectrometry ( UPLC-MS/MS). The results showed that 8 medium-and short-chain PFCs including C₄ and C₈ perfluorinated sulfonates (PFSAs) and C₄-C₉ perfluorinated carboxylic acids (PFCAs) were detected in the surface waters. The total concentrations of PFCs ranged from 0.98 to 609 ng · L⁻¹, while perfluorooctanoic acid (PFOA) dominated, with range of 0.59-538 ng L⁻¹, and perfluorooctane sulfonate (PFOS) was detected at lower levels, ranging from 0 to 2.48 ng · L⁻¹. The spatial distribution of PFCs varied, and the pollutant concentrations at the sampling sites located in upstream of the river such as Lanjiangkou and Jiangjunyan were relatively high, PFCs concentration showed a decreasing trend from the upstream to the downstream. According to the ratio of feature components, PFCs in surface water of QR originated largely from the input of direct sewage emissions. Taken together, the PFCs pollution was highly correlated with the upstream of Qiantang River valley's industry distribution, and most of the mass load in the investigated river was attributed to upstream running water with a minor influence from the wastewater discharges along the river basin. Overall, the results presented here indicated that greater attention should be given to the contamination of PFCs, especially for PFOA in water body of QR. PMID:27011982

  11. Light-induced reversible modification of the work function of a new perfluorinated biphenyl azobenzene chemisorbed on Au (111)

    NASA Astrophysics Data System (ADS)

    Masillamani, Appan Merari; Osella, Silvio; Liscio, Andrea; Fenwick, Oliver; Reinders, Federica; Mayor, Marcel; Palermo, Vincenzo; Cornil, Jérôme; Samorì, Paolo

    2014-07-01

    We describe the synthesis of a novel biphenyl azobenzene derivative exhibiting: (i) a protected thiol anchoring group in the α-position to readily form self-assembled monolayers (SAMs) on Au surfaces; and (ii) a terminal perfluorinated benzene ring in the ω-position to modify the surface properties. The design of this molecule ensured both an efficient in situ photoswitching between the trans and cis isomers when chemisorbed on Au(111), due to the presence of a biphenyl bridge between the thiol protected anchoring group and the azo dye, and a significant variation of the work function of the SAM in the two isomeric states, induced by the perfluorinated phenyl head group. By exploiting the light responsive nature of the chemisorbed molecules, it is possible to dynamically modify in situ the work function of the SAM-covered electrode, as demonstrated both experimentally and by quantum-chemical calculations, revealing changes in work function up to 220 meV. These findings are relevant for tuning the work function of metallic electrodes, and hence to dynamically modulate charge injection at metal-semiconductor interfaces for organic opto-electronic applications.We describe the synthesis of a novel biphenyl azobenzene derivative exhibiting: (i) a protected thiol anchoring group in the α-position to readily form self-assembled monolayers (SAMs) on Au surfaces; and (ii) a terminal perfluorinated benzene ring in the ω-position to modify the surface properties. The design of this molecule ensured both an efficient in situ photoswitching between the trans and cis isomers when chemisorbed on Au(111), due to the presence of a biphenyl bridge between the thiol protected anchoring group and the azo dye, and a significant variation of the work function of the SAM in the two isomeric states, induced by the perfluorinated phenyl head group. By exploiting the light responsive nature of the chemisorbed molecules, it is possible to dynamically modify in situ the work function of

  12. 41 CFR 60-1.3 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 1 2013-07-01 2013-07-01 false Definitions. 60-1.3 Section 60-1.3 Public Contracts and Property Management Other Provisions Relating to Public Contracts...-OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS Preliminary Matters; Equal Opportunity Clause;...

  13. 41 CFR 60-1.3 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 1 2012-07-01 2009-07-01 true Definitions. 60-1.3 Section 60-1.3 Public Contracts and Property Management Other Provisions Relating to Public Contracts...-OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS Preliminary Matters; Equal Opportunity Clause;...

  14. 41 CFR 60-1.3 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 41 Public Contracts and Property Management 1 2014-07-01 2014-07-01 false Definitions. 60-1.3 Section 60-1.3 Public Contracts and Property Management Other Provisions Relating to Public Contracts...-OBLIGATIONS OF CONTRACTORS AND SUBCONTRACTORS Preliminary Matters; Equal Opportunity Clause;...

  15. 36 CFR 1.3 - Penalties.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Penalties. 1.3 Section 1.3 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR GENERAL PROVISIONS... 1 through 7, 12 and 13 of this chapter, within a park area not covered in paragraphs (b) or (c)...

  16. Fused teeth: a review of the treatment options.

    PubMed

    Tuna, E Bahar; Yildirim, Mine; Seymen, Figen; Gencay, Koray; Ozgen, Mehmet

    2009-01-01

    Fused/geminated teeth may cause esthetic, spacing, periodontal, eruption and caries problems. The present study describes two clinical cases of similar dental fusion and compromises different and individualized treatment methods based on the proper treatment needs of a patient. In the first case the fused tooth was separated and the supernumerary tooth was extracted intraorally. In the second case, due to the union structure of a fused tooth up to the apex, extraction and extraoral separation was considered a better alternative than the separation of the fused tooth intraorally. Clinical and radiographic controls of the two cases revealed that the teeth were symptom-free and all clinical and radiographic findings were within normal limits after the long term follow-up periods. Following careful clinical and radiographic examination and diagnosis, extraoral hemi-section and immediate replantation may be considered as an alternative treatment in appropriate cases where a permanent tooth is fused with a supernumerary one.

  17. Synthesis of 1,3,3-trinitroazetidine

    DOEpatents

    Hiskey, Michael A.; Coburn, Michael D.

    1994-01-01

    A process of preparing 1,3,3-trinitroazetidine including forming a 5-hydroxymethyl-5-nitro-1-alkyltetrahydro-1,3-oxazine, e.g., reacting a 1,3,5-trialkyl hexahydrotriazine and tris(hydroxymethyl)nitromethane, ring opening said 5-hydroxymethyl-5-nitro-1-alkyltetrahydro-1,3-oxazine to form a 3-alkylamino-2-hydroxymethyl-2-nitro-1-propanol salt, ring closing said 3-alkylamino-2-hydroxymethyl-2-nitro-1-propanol salt to form a 3-hydroxymethyl-3-nitro-1-alkylazetidine salt, nitrating said 3-hydroxymethyl-3-nitro-1-alkylazetidine salt to form a 1-alkyl-3,3-dinitroazetidine, and converting said 1-alkyl-3,3-dinitroazetidine into 1,3,3-trinitroazetidine is disclosed.

  18. Synthesis of 1,3,3-trinitroazetidine

    DOEpatents

    Hiskey, M.A.; Coburn, M.D.

    1994-08-09

    A process of preparing 1,3,3-trinitroazetidine includes forming a 5-hydroxymethyl-5-nitro-1-alkyltetrahydro-1,3-oxazine, e.g., reacting a 1,3,5-trialkyl hexahydrotriazine and tris(hydroxymethyl)nitromethane, ring opening said 5-hydroxymethyl-5-nitro-1-alkyltetrahydro-1,3-oxazine to form a 3-alkylamino-2-hydroxymethyl-2-nitro-1-propanol salt, ring closing said 3-alkylamino-2-hydroxymethyl-2-nitro-1-propanol salt to form a 3-hydroxymethyl-3-nitro-1-alkylazetidine salt, nitrating said 3-hydroxymethyl-3-nitro-1-alkylazetidine salt to form a 1-alkyl-3,3-dinitroazetidine, and converting said 1-alkyl-3,3-dinitroazetidine into 1,3,3-trinitroazetidine is disclosed. 1 fig.

  19. Existence of nonpoint source of perfluorinated compounds and their loads in the Tsurumi River basin, Japan.

    PubMed

    Zushi, Yasuyuki; Takeda, Tomoharu; Masunaga, Shigeki

    2008-04-01

    Products containing perfluorinated compounds (PFCs) have been widely used during the last 50 years. As a result, worldwide environmental pollution by PFCs has been reported. The sources of PFC pollution in the aquatic environment have been poorly understood. In this study, river water and sewage treatment plant (STP) effluent were sampled along the stretch of the Tsurumi River and also at a fixed station in the river. The concentrations of perfluorooctanesulfonate (PFOS), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were measured. With an increase in river flow rate, it was observed that the PFC concentrations in the river water at fixed station were remained the same or increased for PFOS (179.9+/-34.4-179.6+/-69.5 ng l(-1)), PFHxA (5.5+/-0.8-9.0+/-2.6 ng l(-1)), PFHpA (3.1+/-0.3-4.4+/-1.0 ng l(-1)), and PFOA (15.9+/-0.3-13.4+/-2.5 ng l(-1)) whereas the concentration of PFNA (38.0+/-3.3-15.4+/-3.0 ng l(-1)) and PFDA (3.9+/-0.3-2.1+/-0.3 ng l(-1)) were decreased. On the other hand, the loads of every PFC increased with an increase in river flow rate. The loads of PFCs in rain runoff were estimated to be 2-11 times greater than those in STP effluents that are discharged into the river. These results indicate the existence of a PFC nonpoint source (NPS) and its impact to the total PFC load of river is significant.

  20. Catalytic defluorination of perfluorinated aromatics under oxidative conditions using N-bridged diiron phthalocyanine.

    PubMed

    Colomban, Cédric; Kudrik, Evgenij V; Afanasiev, Pavel; Sorokin, Alexander B

    2014-08-13

    Carbon-fluorine bonds are the strongest single bonds in organic chemistry, making activation and cleavage usually associated with organometallic and reductive approaches particularly difficult. We describe here an efficient defluorination of poly- and perfluorinated aromatics under oxidative conditions catalyzed by the μ-nitrido diiron phthalocyanine complex [(Pc)Fe(III)(μ-N)Fe(IV)(Pc)] under mild conditions (hydrogen peroxide as the oxidant, near-ambient temperatures). The reaction proceeds via the formation of a high-valent diiron phthalocyanine radical cation complex with fluoride axial ligands, [(Pc)(F)Fe(IV)(μ-N)Fe(IV)(F)(Pc(+•))], which was isolated and characterized by UV-vis, EPR, (19)F NMR, Fe K-edge EXAFS, XANES, and Kβ X-ray emission spectroscopy, ESI-MS, and electrochemical techniques. A wide range of per- and polyfluorinated aromatics (21 examples), including C6F6, C6F5CF3, C6F5CN, and C6F5NO2, were defluorinated with high conversions and high turnover numbers. [(Pc)Fe(III)(μ-N)Fe(IV)(Pc)] immobilized on a carbon support showed increased catalytic activity in heterogeneous defluorination in water, providing up to 4825 C-F cleavages per catalyst molecule. The μ-nitrido diiron structure is essential for the oxidative defluorination. Intramolecular competitive reactions using C6F3Cl3 and C6F3H3 probes indicated preferential transformation of C-F bonds with respect to C-Cl and C-H bonds. On the basis of the available data, mechanistic issues of this unusual reactivity are discussed and a tentative mechanism of defluorination under oxidative conditions is proposed.

  1. Micro-solid phase extraction of perfluorinated carboxylic acids from human plasma.

    PubMed

    Lashgari, Maryam; Lee, Hian Kee

    2016-02-01

    Micro-solid phase extraction (μ-SPE), with liquid chromatography-tandem mass spectrometry has been developed for the determination of trace levels of perfluorinated carboxylic acids (PFCAs) in human plasma. The μ-SPE sorbent was surfactant-templated mesoporous silica. Extraction time, desorption time and salt concentration were chosen as the most effective parameters and were optimized simultaneously by use of central composite design. Under the optimized extraction conditions, good linearity in the range of 100 and 5000ngL(-1) was obtained with coefficients of determination of between 0.986 and 0.995. The limits of detection (at a signal to noise ratio of 3) were measured to be in the range of between 21.23 and 65.07ngL(-1), and limits of quantification (at a signal to noise ratio of 10) were in the range of between 70.77 and 216.92ngL(-1). The relative recoveries of spiked PFCAs in different samples were in the range of between 87.58 and 102.45%. As expected from the global distribution of PFCs, contaminations at low levels (less than 200ngL(-1)) were detected (with the highest concentration recorded for perfluorooctanoic acid (PFOA)). Considering the complex nature of biological samples and the issue of matrix effects in the analysis of PFCAs, μ-SPE as an extraction method was shown to be advantageous; it combined extraction and concentration in one single step with no additional sample clean-up, and was able to remove significant matrix interferences.

  2. Bioaccumulation and effects of perfluorinated compounds (PFCs) in zebra mussels (Dreissena polymorpha).

    PubMed

    Fernández-Sanjuan, María; Faria, Melissa; Lacorte, Silvia; Barata, Carlos

    2013-04-01

    Perfluorinated chemicals (PFCs) have been used for many years in numerous industrial products and are known to accumulate in organisms. A recent survey showed that tissue levels of PFCs in aquatic organisms varied among compounds and species being undetected in freshwater zebra mussels Dreissena polymorpha. Here we studied the bioaccumulation kinetics and effects of two major PFCs, perfluorooctane sulfonic acid compound (PFOS) and perfluorooctanoic acid (PFOA), in multixenobiotic transporter activity (MXR) and filtration and oxygen consumption rates in zebra mussel exposed to a range of concentrations of a PCF mixture (1-1,000 μg/L) during 10 days. Results indicate a low potential of the studied PFCs to bioaccumulate in zebra mussel tissues. PFCs altered mussel MXR transporter activity being inhibited at day 1 but not at day 10. Bioaccumulation kinetics of PFCs were inversely related with MXR transporter activity above 9 ng/g wet weight and unrelated at tissue concentration lower than 2 ng/g wet weight suggesting that at high tissue concentrations, these type of compounds may be effluxed out by MXR transporters and as a result have a low potential to be bioaccumulated in zebra mussels. Oxygen consumption rates but not filtering rates were increased in all exposure levels and periods indicating that at environmental relevant concentrations of 1 μg/L, the studied PFCs enhanced oxidative metabolism of mussels. Overall, the results obtained in this study confirm previous findings in the field indicating that an important fraction of PFC accumulated in mussel tissues is eliminated actively by MXR transporters or other processes that are metabolically costly. PMID:22990576

  3. Determination of ten perfluorinated compounds in bluegill sunfish (Lepomis macrochirus) fillets

    SciTech Connect

    Delinsky, Amy D.; Strynar, Mark J.; Nakayama, Shoji F.; Varns, Jerry L.; Ye, XiBiao; McCann, Patricia J.; Lindstrom, Andrew B.

    2009-11-15

    A rigorous solid phase extraction/liquid chromatography/tandem mass spectrometry method for the measurement of 10 perfluorinated compounds (PFCs) in fish fillets is described and applied to fillets of bluegill sunfish (Lepomis macrochirus) collected from selected areas of Minnesota and North Carolina. The 4 PFC analytes routinely detected in bluegill fillets were perfluorooctane sulfonate (PFOS), perfluorodecanoic acid (C10), perfluoroundecanoic acid (C11), and perflurododecanoic acid (C12). Measures of method accuracy and precision for these compounds showed that calculated concentrations of PFCs in spiked samples differed by less than 20% from their theoretical values and that the %RSD for repeated measurements was less than 20%. Minnesota samples were collected from areas of the Mississippi River near historical PFC sources, from the St. Croix River as a background site, and from Lake Calhoun, which has no documented PFC sources. PFOS was the most prevalent PFC found in the Minnesota samples, with median concentrations of 47.0-102 ng/g at locations along the Mississippi River, 2.08 ng/g in the St. Croix River, and 275 ng/g in Lake Calhoun. North Carolina samples were collected from two rivers with no known historical PFC sources. PFOS was the predominant analyte in fish taken from the Haw and Deep Rivers, with median concentrations of 30.3 and 62.2 ng/g, respectively. Concentrations of C10, C11, and C12 in NC samples were among the highest reported in the literature, with respective median values of 9.08, 23.9, and 6.60 ng/g in fish from the Haw River and 2.90, 9.15, and 3.46 ng/g in fish from the Deep River. These results suggest that PFC contamination in freshwater fish may not be limited to areas with known historical PFC inputs.

  4. Fast and simple determination of perfluorinated compounds and their potential precursors in different packaging materials.

    PubMed

    Zabaleta, I; Bizkarguenaga, E; Bilbao, D; Etxebarria, N; Prieto, A; Zuloaga, O

    2016-05-15

    A simple and fast analytical method for the determination of fourteen perfluorinated compounds (PFCs), including three perfluoroalkylsulfonates (PFSAs), seven perfluorocarboxylic acids (PFCAs), three perfluorophosphonic acids (PFPAs) and perfluorooctanesulfonamide (PFOSA) and ten potential precursors, including four polyfluoroalkyl phosphates (PAPs), four fluorotelomer saturated acids (FTCAs) and two fluorotelomer unsaturated acids (FTUCAs) in different packaging materials was developed in the present work. In order to achieve this objective the optimization of an ultrasonic probe-assisted extraction (UPAE) method was carried out before the analysis of the target compounds by liquid-chromatography-triple quadrupole-tandem mass spectrometry (LC-QqQ-MS/MS). 7 mL of 1 % acetic acid in methanol and a 2.5-min single extraction cycle were sufficient for the extraction of all the target analytes. The optimized analytical method was validated in terms of recovery, precision and method detection limits (MDLs). Apparent recovery values after correction with the corresponding labeled standard were in the 69-103 % and 62-98 % range for samples fortified at 25 ng/g and 50 ng/g concentration levels, respectively and MDL values in the 0.6-2.2 ng/g range were obtained. The developed method was applied to the analysis of plastic (milk bottle, muffin cup, pre-cooked food wrapper and cup of coffee) and cardboard materials (microwave popcorn bag, greaseproof paper for French fries, cardboard box for pizza and cinema cardboard box for popcorn). To the best of our knowledge, this is the first method that describes the determination of fourteen PFCs and ten potential precursors in packaging materials. Moreover, 6:2 FTCA, 6:2 FTUCA and 5:3 FTCA analytes were detected for the first time in microwave popcorn bags. PMID:26992531

  5. Determinants of maternal and fetal exposure and temporal trends of perfluorinated compounds.

    PubMed

    Ode, Amanda; Rylander, Lars; Lindh, Christian H; Källén, Karin; Jönsson, Bo A G; Gustafsson, Peik; Olofsson, Per; Ivarsson, Sten A; Rignell-Hydbom, Anna

    2013-11-01

    In recent years, some perfluorinated compounds (PFCs) have been identified as potentially hazardous substances which are harmful to the environment and human health. According to limited data, PFC levels in humans could be influenced by several determinants. However, the findings are inconsistent. In the present study, perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) were measured in paired maternal and cord serum samples (N=237) collected between 1978 and 2001 in Southern Sweden to study the relationship between these and to investigate several potential determinants of maternal and fetal exposure to PFCs. Time trends of PFCs in Swedish women were also evaluated. The study is a part of the Fetal Environment and Neurodevelopment Disorders in Epidemiological Research project. PFOS, PFOA, and PFNA levels (median) were higher in maternal serum (15, 2.1, and 0.24 ng/ml, respectively) than in cord serum (6.5, 1.7, and 0.20 ng/ml, respectively). PFC levels were among the highest in women originating from the Nordic countries and the lowest in women from the Middle East, North Africa, and sub-Saharan Africa. Multiparous women had lower serum PFOA levels (1.7 ng/ml) than primiparous women (2.4 ng/ml). Maternal age, body mass index, cotinine levels, and whether women carried male or female fetuses did not affect serum PFC concentrations. Umbilical cord serum PFC concentrations showed roughly similar patterns as the maternal except for the gestational age where PFC levels increased with advancing gestational age. PFOS levels increased during the study period in native Swedish women. In summary, PFOS levels tend to increase while PFOA and PFNA levels were unchanged between 1978 and 2001 in our study population. Our results demonstrate that maternal country of origin, parity, and gestational age might be associated with PFC exposure. PMID:23436123

  6. Human exposure to perfluorinated compounds in Catalonia, Spain: contribution of drinking water and fish and shellfish.

    PubMed

    Domingo, José L; Ericson-Jogsten, Ingrid; Perelló, Gemma; Nadal, Martí; Van Bavel, Bert; Kärrman, Anna

    2012-05-01

    In this study, the concentrations of 15 perfluorinated compounds (PFCs) were analyzed in 30 water samples collected in Catalonia (Spain) at three stages of the drinking water treatment process in several water purification plants. In addition, the concentrations of 13 PFCs were determined in samples of fish and shellfish collected from coastal areas of Catalonia. The intake of PFCs through both pathways, drinking water intake and fish and shellfish consumption, was also estimated. In water samples, the highest mean concentrations corresponded to perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) (1.81 and 2.40 ng/L, respectively), whereas perfluorodecanosulfonate (PFDS) and perfluorotetradecanoic acid (PFTDA) were under their respective limits of detection in all analyzed samples. The results show that although the current treatment processes caused slight reductions in PFC concentrations, these processes did not mean significant changes in the amounts of PFCs already contained in the raw water. Among the analyzed PFCs in fish and shellfish, only seven compounds could be detected in at least one composite sample. PFOS showed the highest mean concentration (2.70 ng/g fw), being detected in all species with the exception of mussels. With regard to PFOA (mean, 0.074 ng/g fw), the highest concentrations were detected in prawn and hake (0.098 and 0.091 ng/g fw, respectively). The current exposure to PFCs through consumption of fish and shellfish indicates that it should not be of concern for the consumers. The amounts ingested are well below the recommended tolerable daily intakes, at least for those PFCs for which information is available.

  7. Perfluorinated acids as novel chemical tracers of global circulation of ocean waters.

    PubMed

    Yamashita, Nobuyoshi; Taniyasu, Sachi; Petrick, Gert; Wei, Si; Gamo, Toshitaka; Lam, Paul K S; Kannan, Kurunthachalam

    2008-01-01

    Perfluorinated acids (PFAs) such as perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) are global environmental contaminants. The physicochemical properties of PFAs are unique in that they have high water solubilities despite the low reactivity of carbon-fluorine bond, which also imparts high stability in the environment. Because of the high water solubilities, the open-ocean water column is suggested to be the final sink for PFOS and PFOA. However, little is known on the distribution of PFAs in the oceans around the world. Here we describe the horizontal (spatial) and vertical distribution of PFAs in ocean waters worldwide. PFOS and PFOA concentrations in the North Atlantic Ocean ranged from 8.6 to 36pg l(-1) and from 52 to 338pg l(-1), respectively, whereas the corresponding concentrations in the Mid Atlantic Ocean were 13-73pg l(-1) and 67-439pg l(-1). These were completely different from the surface waters of the South Pacific Ocean and the Indian Ocean (overall range of <5-11pg l(-1) for PFOS and PFOA). Vertical profiles of PFAs in the marine water column were associated with the global ocean circulation theory. Vertical profiles of PFAs in water columns from the Labrador Sea reflected the influx of the North Atlantic Current in surface waters, the Labrador Current in subsurface waters, and the Denmark Strait Overflow Water in deep layers below 2000m. Striking differences in the vertical and spatial distribution of PFAs, depending on the oceans, suggest that these persistent acids can serve as useful chemical tracers to allow us to study oceanic transportation by major water currents. The results provide evidence that PFA concentrations and profiles in the oceans adhere to a pattern consistent with the global "Broecker's Conveyor Belt" theory of open ocean water circulation.

  8. Genotoxicity of perfluorinated chemicals (PFCs) to the green mussel (Perna viridis).

    PubMed

    Liu, Changhui; Chang, Victor W C; Gin, Karina Y H; Nguyen, Viet Tung

    2014-07-15

    Concerns regarding perfluorinated chemicals (PFCs) have grown significantly in recent years. However, regulations and guidelines regarding the emission and treatment of PFCs are still missing in most parts of the world, mostly due to the lack of PFC toxicity data. In the current study, the genotoxic effects of four common PFCs, named perfluorooctanesulfonate (PFOS), perfluoroocanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were investigated on marine mussels. The effects of exposure time and concentration on the toxic behavior of the compounds were also examined. Genotoxicity of PFCs was assessed in biomarker assays, showing that exposure to the target compounds could damage the organism's genetic material to varying extents, including DNA strand breaks and fragmentation, chromosomal breaks and apoptosis. The adverse effects increased with both exposure concentration and time and were related with the organism burden of PFCs. The integrated biomarker response analysis demonstrated that PFOS exhibited a higher genotoxicity than the other tested compounds. The EC50 values and confidence intervals based on integrative genotoxicity were 33 (29-37), 594 (341-1036), 195 (144-265) and 78 (73-84) μg/L for PFOS, PFOA, PFNA and PFDA respectively, classifying PFOS as a highly genotoxic compound. Although primary DNA damage was shown to be recoverable after exposure ceased, permanent genetic damage caused by elevated PFC concentrations was not restored. This is the first ecotoxicity study of PFCs that focuses on the genotoxic effects of the compounds, clearly indicating the genotoxicity of the tested PFCs and demonstrating that functional groups have a major impact on the compounds' genotoxic behavior.

  9. Review on the occurrence, fate and removal of perfluorinated compounds during wastewater treatment.

    PubMed

    Arvaniti, Olga S; Stasinakis, Athanasios S

    2015-08-15

    Perfluorinated compounds (PFCs) consist of a fully fluorinated hydrophobic alkyl chain attached to a hydrophilic end group. Due to their wide use in several industrial and household applications, they have been detected in numerous Sewage Treatment Plants (STPs) during the last ten years. The present review reports the occurrence of 22 PFCs (C4-C14, C16, C18 carboxylates; C4-C8 and C10 sulfonates; 3 sulfonamides) in municipal or/and industrial wastewater, originating from 24 monitoring studies. PFCs levels in sewage sludge have also been reported using data from 12 studies. Most of the above monitoring data originate from the USA, North Europe and Asia and concern perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA), while limited information is available from Mediterranean area, Canada and Australia. PFCs concentrations range up to some hundreds ng/L and some thousands ng/g dry weight in raw wastewater and sludge, respectively. They are not significantly removed during secondary biological treatment, while their concentrations in treated wastewater are often higher compared to raw sewage. Their biodegradation during wastewater treatment does not seem possible; whereas some recent studies have noted the potential transformation of precursor compounds to PFCs during biological wastewater treatment. PFCs sorption onto sludge has been studied in depth and seems to be an important mechanism governing their removal in STPs. Concerning tertiary treatment technologies, significant PFCs removal has been observed using activated carbon, nanofiltration, reverse osmosis or applying advanced oxidation and reduction processes. Most of these studies have been conducted using pure water, while in many cases the experiments have been performed under extreme laboratory conditions (high concentrations, high radiation source, temperature or pressure). Future efforts should be focused on better understanding of biotransformation processes occurred in aerobic and anaerobic

  10. Perfluorinated alkyl substances (PFAS) in terrestrial environments in Greenland and Faroe Islands.

    PubMed

    Bossi, Rossana; Dam, Maria; Rigét, Frank F

    2015-06-01

    Perfluorinated alkylated substances (PFASs) have been measured in liver samples from terrestrial organisms from Greenland and the Faeroe Islands. Samples from ptarmigan (West Greenland), reindeer (southwest-Greenland), muskox (East Greenland), and land-locked Arctic char from southwest Greenland and the Faroe Islands were analyzed. In addition, PFASs levels in land-locked brown trout from Faroese lakes are reported. Of the 17 PFASs analyzed in the samples the following compounds were detected: PFOS, PFNA, PFDA, PFUnA, PFDoA, PFTrA, and PFTeA. PFNA was the compound detected in most samples and in all species. However, the compound detected at highest concentration was dependent on species, with overall highest concentrations of PFTrA and PFUnA being detected in trout liver from Lake á Mýranar (Faroe Islands). In muskox, the PFAS occurring at highest concentrations was PFDA, which was among the PFAS detected at lowest concentrations in freshwater fish, and was only detected in one individual ptarmigan. The concentration of PFOS, PFDoA and PFTrA in Arctic char from Greenland and Faroe Islands were similar, whereas the concentration of PFNA, PFDA and PFUnA were higher in Arctic char than those from Greenland. The opposite was observed for PFTeA. The PFASs occurring at highest concentrations in trout were PFTrA and PFUnA. Arctic char from Lake á Mýranar had much lower concentrations of PFTrA and PFUnA than in trout from the lakes analyzed, but a higher concentration of PFTeA than trout from the same lake. A clear pattern with odd-carbon number homologues concentrations higher than the next lower even homologue was observed in fish samples, which is consistent with the hypothesis of transport of volatile precursors to remote regions.

  11. Levels of chlorinated, brominated, and perfluorinated contaminants in birds of prey spanning multiple trophic levels.

    PubMed

    Yordy, Jennifer E; Rossman, Sam; Ostrom, Peggy H; Reiner, Jessica L; Bargnesi, Keely; Hughes, Stacy; Elliot, James D

    2013-04-01

    Birds of prey occupy high trophic levels and can consequently bioaccumulate high levels of environmental contaminants. To evaluate exposure to past- and current-use pollutants, we measured legacy contaminants (i.e., polychlorinated biphenyls [PCBs]; organochlorine pesticides, e.g., DDT), contaminants of emerging concern (polybrominated diphenyl ethers [PBDEs]; perfluorinated compounds [PFCs]), and stable isotopes (δ(13)C, δ(15)N) in 26 birds of prey (10 species) from coastal South Carolina (USA) sampled in 2009 and 2010. Nitrogen isotope ratios (δ(15)N) ranged from 5.2% to 13.7%, indicating the birds of prey spanned two to three trophic levels. Legacy contaminant levels were highly variable but generally comparable to levels reported previously for birds of prey in the southeast US, suggesting exposure has not declined substantially over the past 40 yr. Despite their status as newly emerging environmental contaminants, PFC levels were within the same order of magnitude as legacy contaminants. Although PBDEs were less prevalent, levels were among the greatest observed in wildlife to date (∑PBDEs max. 200 μg/g lipid). Relative contaminant profiles also varied between birds of prey utilizing low and high trophic levels; specifically PFCs contributed to a larger proportion of the contaminant burden in birds utilizing high trophic levels, whereas the legacy pesticide mirex was a larger contributor in low-trophic-level birds, indicating that relative exposure is in part dependent on foraging ecology. This study demonstrates that birds of prey continue to face exposure to legacy contaminants as well as newly emerging contaminants at levels of concern. PMID:23568910

  12. In vitro evaluation of the immunotoxic potential of perfluorinated compounds (PFCs)

    SciTech Connect

    Corsini, Emanuela; Avogadro, Anna; Galbiati, Valentina; Dell'Agli, Mario; Marinovich, Marina; Galli, Corrado L.; Germolec, Dori R.

    2011-01-15

    There is evidence from both epidemiology and laboratory studies that perfluorinated compounds may be immunotoxic, affecting both cell-mediated and humoral immunity. The overall goal of this study was to investigate the mechanisms underlying the immunotoxic effects of perfluorooctane sulfonate (PFOS) and perfluorooctane acid (PFOA), using in vitro assays. The release of the pro-inflammatory cytokines IL-6, IL-8, and TNF-{alpha} was evaluated in lipolysaccharide (LPS)-stimulated human peripheral blood leukocytes and in the human promyelocytic cell line THP-1, while the release of IL-4, IL-10 and IFN-{gamma} was evaluated in phytohaemagglutinin (PHA)-stimulated peripheral blood leukocytes. PFOA and PFOS suppressed LPS-induced TNF-{alpha} production in primary human cultures and THP-1 cells, while IL-8 was suppressed only in THP-1 cells. IL-6 release was decreased only by PFOS. Both PFOA and PFOS decreased T-cell derived, PHA-induced IL-4 and IL-10 release, while IFN-{gamma} release was affected only by PFOS. In all instances, PFOS was more potent than PFOA. Mechanistic investigations carried out in THP-1 cells demonstrated that the effect on cytokine release was pre-transcriptional, as assessed by a reduction in LPS-induced TNF-{alpha} mRNA expression. Using siRNA, a role for PPAR-{alpha} could be demonstrated for PFOA-induced immunotoxicity, while an inhibitory effect on LPS-induced I-{kappa}B degradation could explain the immunomodulatory effect of PFOS. The dissimilar role of PPAR-{alpha} in PFOA and PFOS-induced immunotoxicity was consistent with the differing effects observed on LPS-induced MMP-9 release: PFOA, as the PPAR-{alpha} agonist fenofibrate, modulated the release, while PFOS had no effect. Overall, these studies suggest that PFCs directly suppress cytokine secretion by immune cells, and that PFOA and PFOS have different mechanisms of action.

  13. Perfluorinated Compounds, Polychlorinated Biphenyls, and Organochlorine Pesticide Contamination in Composite Food Samples from Dallas, Texas, USA

    PubMed Central

    Schecter, Arnold; Colacino, Justin; Haffner, Darrah; Patel, Keyur; Opel, Matthias; Päpke, Olaf; Birnbaum, Linda

    2010-01-01

    Objectives The objective of this article is to extend our previous studies of persistent organic pollutant (POP) contamination of U.S. food by measuring perfluorinated compounds (PFCs), organochlorine pesticides, and polychlorinated biphenyls (PCBs) in composite food samples. This study is part of a larger study reported in two articles, the other of which reports levels of polybrominated diphenyl ethers and hexabromocyclododecane brominated flame retardants in these composite foods [Schecter et al. 2010. Polybrominated diphenyl ethers (PBDEs) and hexabromocyclodecane (HBCD) in composite U.S. food samples, Environ Health Perspect 118:357–362]. Methods In this study we measured concentrations of 32 organochlorine pesticides, 7 PCBs, and 11 PFCs in composite samples of 31 different types of food (310 individual food samples) purchased from supermarkets in Dallas, Texas (USA), in 2009. Dietary intake of these chemicals was calculated for an average American. Results Contamination varied greatly among chemical and food types. The highest level of pesticide contamination was from the dichlorodiphenyltrichloroethane (DDT) metabolite p,p′- dichlorodiphenyldichloroethylene, which ranged from 0.028 ng/g wet weight (ww) in whole milk yogurt to 2.3 ng/g ww in catfish fillets. We found PCB congeners (28, 52, 101, 118, 138, 153, and 180) primarily in fish, with highest levels in salmon (PCB-153, 1.2 ng/g ww; PCB-138, 0.93 ng/g ww). For PFCs, we detected perfluorooctanoic acid (PFOA) in 17 of 31 samples, ranging from 0.07 ng/g in potatoes to 1.80 ng/g in olive oil. In terms of dietary intake, DDT and DDT metabolites, endosulfans, aldrin, PCBs, and PFOA were consumed at the highest levels. Conclusion Despite product bans, we found POPs in U.S. food, and mixtures of these chemicals are consumed by the American public at varying levels. This suggests the need to expand testing of food for chemical contaminants. PMID:20146964

  14. Perfluorinated compounds in infiltrated river rhine water and infiltrated rainwater in coastal dunes.

    PubMed

    Eschauzier, Christian; Haftka, Joris; Stuyfzand, Pieter J; de Voogt, Pim

    2010-10-01

    Different studies have shown that surface waters contain perfluorinated compounds (PFCs) in the low ng/L range. Surface waters are used to produce drinking water and PFCs have been shown to travel through the purification system and form a potential threat to human health. The specific physicochemical properties of PFCs cause them to be persistent and some of them to be bioaccumulative and toxic in the environment. This study investigates the evolvement of PFC concentrations in Rhine water and rainwater during dune water infiltration processes over a transect in the dune area of the western part of The Netherlands. The difference between infiltrated river water and rainwater in terms of PFC composition was investigated. Furthermore, isomer profiles were investigated. The compound perfluorobutanesulfonate (PFBS) was found at the highest concentrations of all PFCs investigated, up to 37 ng/L in infiltrated river water (71 ± 13% of ΣPFCs). This is in contrast with the predominant occurrence of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) reported in literature. The concentrations of PFBS found in infiltrated river Rhine water were significantly higher than those in infiltrated rainwater. For perfluorohexanesulfonate (PFHxS) the opposite was found: infiltrated rainwater contained more than infiltrated river water. The concentrations of PFOA, perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), PFBS, PFOS, and PFHxS in infiltrated river water showed an increasing trend with decreasing age of the water. The relative contribution of the branched PFOA and PFOS isomers to total concentrations of PFOA and PFOS showed a decreasing trend with decreasing age of the water.

  15. Perfluorinated alkyl substances (PFAS) in terrestrial environments in Greenland and Faroe Islands.

    PubMed

    Bossi, Rossana; Dam, Maria; Rigét, Frank F

    2015-06-01

    Perfluorinated alkylated substances (PFASs) have been measured in liver samples from terrestrial organisms from Greenland and the Faeroe Islands. Samples from ptarmigan (West Greenland), reindeer (southwest-Greenland), muskox (East Greenland), and land-locked Arctic char from southwest Greenland and the Faroe Islands were analyzed. In addition, PFASs levels in land-locked brown trout from Faroese lakes are reported. Of the 17 PFASs analyzed in the samples the following compounds were detected: PFOS, PFNA, PFDA, PFUnA, PFDoA, PFTrA, and PFTeA. PFNA was the compound detected in most samples and in all species. However, the compound detected at highest concentration was dependent on species, with overall highest concentrations of PFTrA and PFUnA being detected in trout liver from Lake á Mýranar (Faroe Islands). In muskox, the PFAS occurring at highest concentrations was PFDA, which was among the PFAS detected at lowest concentrations in freshwater fish, and was only detected in one individual ptarmigan. The concentration of PFOS, PFDoA and PFTrA in Arctic char from Greenland and Faroe Islands were similar, whereas the concentration of PFNA, PFDA and PFUnA were higher in Arctic char than those from Greenland. The opposite was observed for PFTeA. The PFASs occurring at highest concentrations in trout were PFTrA and PFUnA. Arctic char from Lake á Mýranar had much lower concentrations of PFTrA and PFUnA than in trout from the lakes analyzed, but a higher concentration of PFTeA than trout from the same lake. A clear pattern with odd-carbon number homologues concentrations higher than the next lower even homologue was observed in fish samples, which is consistent with the hypothesis of transport of volatile precursors to remote regions. PMID:25482975

  16. Determination of perfluorinated compounds (PFCs) in various foodstuff packaging materials used in the Greek market.

    PubMed

    Zafeiraki, Effrosyni; Costopoulou, Danae; Vassiliadou, Irene; Bakeas, Evangelos; Leondiadis, Leondios

    2014-01-01

    Perfluorinated compounds (PFCs) are used in food packaging materials as coatings/additives for oil and moisture resistance. In the current study, foodstuff-packaging materials collected from the Greek market, made of paper, paperboard or aluminum foil were analyzed for the determination of PFCs. For the analysis of the samples, pressurized liquid extraction (PLE), liquid chromatography–tandem mass spectrometry (LC–MS/MS) and isotope dilution method were applied to develop a specific and sensitive method of analysis for the quantification of 12 PFCs: perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoA), perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS) and perfluorooctane sulfonate (PFOS) and the qualitative detection of 5 more: perfluorotridecanoic acid (PFTrDA), perfluorotetradecanoic acid (PFTeDA), perflyohexadecanoic acid (PFHxDA), perfluorooctadecanoic acid (PFODA) and perfluorodecane sulfonate (PFDS). No PFCs were quantified in aluminum foil wrappers, baking paper materials or beverage cups. PFTrDA, PFTeDA and PFHxDA were detected in fast food boxes. In the ice cream cup sample only PFHxA was found. On the other hand, several PFCs were quantified and detected in fast food wrappers, while the highest levels of PFCs were found in the microwave popcorn bag. PFOA and PFOS were not detected in any of the samples. Compared to other studies from different countries, very low concentrations of PFCs were detected in the packaging materials analyzed. Our results suggest that probably no serious danger for consumers’ health can be associated with PFCs contamination of packaging materials used in Greece. PMID:24367824

  17. Perfluorinated alkylated acids in groundwater and drinking water: identification, origin and mobility.

    PubMed

    Eschauzier, Christian; Raat, Klaasjan J; Stuyfzand, Pieter J; De Voogt, Pim

    2013-08-01

    Human exposure to perfluorinated alkylated acids (PFAA) occurs primarily via the dietary intake and drinking water can contribute significantly to the overall PFAA intake. Drinking water is produced from surface water and groundwater. Waste water treatment plants have been identified as the main source for PFAA in surface waters and corresponding drinking water. However, even though groundwater is an important source for drinking water production, PFAA sources remain largely uncertain. In this paper, we identified different direct and indirect sources of PFAA to groundwater within the catchment area of a public supply well field (PSWF) in The Netherlands. Direct sources were landfill leachate and water draining from a nearby military base/urban area. Indirect sources were infiltrated rainwater. Maximum concentrations encountered in groundwater within the landfill leachate plume were 1.8 μg/L of non branched perfluorooctanoic acid (L-PFOA) and 1.2 μg/L of perfluorobutanoic acid (PFBA). Sum concentrations amounted to 4.4 μg/L total PFAA. The maximum concentration of ΣPFAA in the groundwater originating from the military camp was around 17 ng/L. Maximum concentrations measured in the groundwater halfway the landfill and the PWSF (15 years travel distance) were 29 and 160 ng/L for L-PFOA and PFBA, respectively. Concentrations in the groundwater pumping wells (travel distance >25 years) were much lower: 0.96 and 3.5 ng/L for L-PFOA and PFBA, respectively. The chemical signature of these pumping wells corresponded to the signature encountered in other wells sampled which were fed by water that had not been in contact with potential contaminant sources, suggesting a widespread diffuse contamination from atmospheric deposition.

  18. Prenatal exposure to perfluorinated compounds affects thyroid hormone levels in newborn girls.

    PubMed

    Shah-Kulkarni, Surabhi; Kim, Byung-Mi; Hong, Yun-Chul; Kim, Hae Soon; Kwon, Eun Jin; Park, Hyesook; Kim, Young Ju; Ha, Eun-Hee

    2016-09-01

    Perfluorinated compounds (PFCs) are ubiquitous in the environment and have been detected in humans and wildlife. Exposure to PFCs has decreased in the United States recently, while exposure to PFCs continues in Asian countries, which represents a public health concern. Various mechanisms by which PFCs affect fetal growth have been proposed, such as activation of peroxisome proliferators, disruption of thyroid hormones and changes in lipid metabolism. However, the overall evidence for an association with thyroid hormones is not strong. Therefore, we examined the effect of various prenatal PFCs on cord blood thyroid hormones: triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH) levels, and explored the endocrine disrupting effect of these PFCs on thyroid hormone levels in children according to gender. Two hundred and seventy-nine study participants were selected from among the enrolled participants in the Ewha Birth & Growth Retrospective Cohort, a retrospective birth cohort study conducted at Ewha Womans University Hospital, Seoul, Korea between 2006 and 2010. A generalized linear model was constructed to explore the association of PFCs and thyroid hormones. Further, an analysis stratified by gender was conducted. Our study shows that cord blood perfluoro n-pentanoic acid (PFPeA) was positively associated with cord blood T4 (p=0.01) level. Gender-specific analysis showed that prenatal PFCs: PFPeA and Perfluorohexane sulfonic acid (PFHxS) exposure significantly increased T4 (p<0.01) and T3 (p=0.03), respectively, while perfluorononanoic acid (PFNA) decreased TSH (p=0.04) concentration in newborn girls. Thus, prenatal PFC exposure may disrupt thyroid hormone homeostasis. Thyroid hormones play a crucial role in fetal development and may have gender specific action. Hence, these results are of utmost importance in high-risk groups, such as pregnant women and children. PMID:27395336

  19. Bioaccumulation and effects of perfluorinated compounds (PFCs) in zebra mussels (Dreissena polymorpha).

    PubMed

    Fernández-Sanjuan, María; Faria, Melissa; Lacorte, Silvia; Barata, Carlos

    2013-04-01

    Perfluorinated chemicals (PFCs) have been used for many years in numerous industrial products and are known to accumulate in organisms. A recent survey showed that tissue levels of PFCs in aquatic organisms varied among compounds and species being undetected in freshwater zebra mussels Dreissena polymorpha. Here we studied the bioaccumulation kinetics and effects of two major PFCs, perfluorooctane sulfonic acid compound (PFOS) and perfluorooctanoic acid (PFOA), in multixenobiotic transporter activity (MXR) and filtration and oxygen consumption rates in zebra mussel exposed to a range of concentrations of a PCF mixture (1-1,000 μg/L) during 10 days. Results indicate a low potential of the studied PFCs to bioaccumulate in zebra mussel tissues. PFCs altered mussel MXR transporter activity being inhibited at day 1 but not at day 10. Bioaccumulation kinetics of PFCs were inversely related with MXR transporter activity above 9 ng/g wet weight and unrelated at tissue concentration lower than 2 ng/g wet weight suggesting that at high tissue concentrations, these type of compounds may be effluxed out by MXR transporters and as a result have a low potential to be bioaccumulated in zebra mussels. Oxygen consumption rates but not filtering rates were increased in all exposure levels and periods indicating that at environmental relevant concentrations of 1 μg/L, the studied PFCs enhanced oxidative metabolism of mussels. Overall, the results obtained in this study confirm previous findings in the field indicating that an important fraction of PFC accumulated in mussel tissues is eliminated actively by MXR transporters or other processes that are metabolically costly.

  20. Perfluorinated compounds (PFCs) in the atmosphere of Shenzhen, China: Spatial distribution, sources and health risk assessment.

    PubMed

    Liu, Baolin; Zhang, Hong; Yao, Dan; Li, Juying; Xie, Liuwei; Wang, Xinxuan; Wang, Yanping; Liu, Guoqing; Yang, Bo

    2015-11-01

    This study investigated the occurrence of perfluorinated compounds (PFCs) in the atmosphere of Shenzhen, China. 11 PFCs, including two perfluoroalkyl sulfonic acids (PFSAs, C6 and C8) and perfluoroalkyl carboxylic acids (PFCAs, C4-12) were determined by high performance liquid chromatography-negative electrospray ionization-tandem mass spectrometry (HPLC/ESI-MS/MS). Total PFC concentrations (∑ PFCs) in the atmospheric samples ranged from 3.4 to 34 pg m(-3) with an average of 15 pg m(-3). Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were the two most abundant PFCs and on average accounted for 35% and 22% of ∑ PFCs, respectively. ∑ PFCs and total PFCA concentrations (∑ PFCAs) showed a tendency of low-lying East West, while the distribution of total PFSA concentrations (∑ PFSAs) was uniform. Higher concentrations of ∑ PFCs were found in Bao'an District which had very well-developed manufacturing industries. PCA model was employed to quantitatively calculate the contributions of sources. The results showed that PFOA-factor, long chain PFCs-factor and PFOS-factor were the three main source categories for PFCs in the atmosphere. Meanwhile, long-distance transport of pollutants from southeastern coastal areas might be another source of PFCs in Shenzhen atmosphere. PFCs in the atmosphere were more positively correlated with the levels PM10 than PM2.5, which indicated PFCs were more likely to adhere to particles with relatively large sizes. The hazard ratios of noncancer risk through breathing based on PFOS and PFOA concentrations were calculated and were less than unity, suggesting that PFCs concentrations may pose no or immediate threat to the residents in Shenzhen.

  1. Perfluorinated compounds in fish from U.S. urban rivers and the Great Lakes.

    PubMed

    Stahl, Leanne L; Snyder, Blaine D; Olsen, Anthony R; Kincaid, Thomas M; Wathen, John B; McCarty, Harry B

    2014-11-15

    Perfluorinated compounds (PFCs) have recently received scientific and regulatory attention due to their broad environmental distribution, persistence, bioaccumulative potential, and toxicity. Studies suggest that fish consumption may be a source of human exposure to perfluorooctane sulfonate (PFOS) or long-chain perfluorocarboxylic acids. Most PFC fish tissue literature focuses on marine fish and waters outside of the United States (U.S.). To broaden assessments in U.S. fish, a characterization of PFCs in freshwater fish was initiated on a national scale using an unequal probability design during the U.S. Environmental Protection Agency's (EPA's) 2008-2009 National Rivers and Streams Assessment (NRSA) and the Great Lakes Human Health Fish Tissue Study component of the 2010 EPA National Coastal Condition Assessment (NCCA/GL). Fish were collected from randomly selected locations--164 urban river sites and 157 nearshore Great Lake sites. The probability design allowed extrapolation to the sampled population of 17,059 km in urban rivers and a nearshore area of 11,091 km(2) in the Great Lakes. Fillets were analyzed for 13 PFCs using high-performance liquid chromatography tandem mass spectrometry. Results showed that PFOS dominated in frequency of occurrence, followed by three other longer-chain PFCs (perfluorodecanoic acid, perfluoroundecanoic acid, and perfluorododecanoic acid). Maximum PFOS concentrations were 127 and 80 ng/g in urban river samples and Great Lakes samples, respectively. The range of NRSA PFOS detections was similar to literature accounts from targeted riverine fish sampling. NCCA/GL PFOS levels were lower than those reported by other Great Lakes researchers, but generally higher than values in targeted inland lake studies. The probability design allowed development of cumulative distribution functions (CDFs) to quantify PFOS concentrations versus the sampled population, and the application of fish consumption advisory guidance to the CDFs resulted in

  2. Fast and simple determination of perfluorinated compounds and their potential precursors in different packaging materials.

    PubMed

    Zabaleta, I; Bizkarguenaga, E; Bilbao, D; Etxebarria, N; Prieto, A; Zuloaga, O

    2016-05-15

    A simple and fast analytical method for the determination of fourteen perfluorinated compounds (PFCs), including three perfluoroalkylsulfonates (PFSAs), seven perfluorocarboxylic acids (PFCAs), three perfluorophosphonic acids (PFPAs) and perfluorooctanesulfonamide (PFOSA) and ten potential precursors, including four polyfluoroalkyl phosphates (PAPs), four fluorotelomer saturated acids (FTCAs) and two fluorotelomer unsaturated acids (FTUCAs) in different packaging materials was developed in the present work. In order to achieve this objective the optimization of an ultrasonic probe-assisted extraction (UPAE) method was carried out before the analysis of the target compounds by liquid-chromatography-triple quadrupole-tandem mass spectrometry (LC-QqQ-MS/MS). 7 mL of 1 % acetic acid in methanol and a 2.5-min single extraction cycle were sufficient for the extraction of all the target analytes. The optimized analytical method was validated in terms of recovery, precision and method detection limits (MDLs). Apparent recovery values after correction with the corresponding labeled standard were in the 69-103 % and 62-98 % range for samples fortified at 25 ng/g and 50 ng/g concentration levels, respectively and MDL values in the 0.6-2.2 ng/g range were obtained. The developed method was applied to the analysis of plastic (milk bottle, muffin cup, pre-cooked food wrapper and cup of coffee) and cardboard materials (microwave popcorn bag, greaseproof paper for French fries, cardboard box for pizza and cinema cardboard box for popcorn). To the best of our knowledge, this is the first method that describes the determination of fourteen PFCs and ten potential precursors in packaging materials. Moreover, 6:2 FTCA, 6:2 FTUCA and 5:3 FTCA analytes were detected for the first time in microwave popcorn bags.

  3. Deuterium Abundance Toward WD2211-495: Results from the Far Ultraviolet Spectroscopic Explorer (FUSE) Mission

    NASA Technical Reports Server (NTRS)

    Hebrard, G.; Lemoine, M.; Vidal-Madjar, A.; Desert, J. M.; LecavelierdesEtangs, A.; Ferlet, R.; Wood, B. E.; Linsky, J. L.; Kruk, J. W.; Chayer, P.; Oegerle, William R. (Technical Monitor)

    2002-01-01

    We present a deuterium abundance analysis of the line of sight toward the white dwarf WD 2211-495 observed with the Far Ultraviolet Spectroscopic Explorer (FUSE). Numerous interstellar lines are detected on the continuum of the stellar spectrum. A thorough analysis was performed through the simultaneous fit of interstellar absorption lines detected in the four FUSE channels of multiple observations with different slits. We excluded all saturated lines in order to reduce possible systematic errors on the column density measurements. We report the determination of the average interstellar D/O and D/N ratios along this line of sight at the 95% confidence level: D/O = 4.0 (+/-1.2) x 10(exp -2); D/N = 4.4 (+/-1.3) x 10(exp -1). In conjunction with FUSE observations of other nearby sight lines, the results of this study will allow a deeper understanding of the present-day abundance of deuterium in the local interstellar medium and its evolution with time.

  4. Buddy: fusing multiple search results together

    NASA Astrophysics Data System (ADS)

    Salerno, John J.; Boulware, Doug M.; Myers, John E.; Khattri, Vishal; Corzillus, Dave R.

    2003-03-01

    If you have ever used a popular search engine on the Internet to search for a specific topic you are interested in, you know that most of the results you get back are unrelated, or do not have the information for which you are searching. Usually you end up looking through many Web pages before you find information. Different search engines give you different ranked results, so how do you choose which one to use? Buddy solves these problems for you. With Buddy you can search multiple search engines with many different queries. Using topic trees to create in depth search queries, utilizing the power of many renowned search engines, with the ability to dynamically create and delete them on the fly, Buddy gives you the results you want on the information you are looking for. Using its unique ranking algorithm the results from multiple search engines are correlated and fused together, removing multiple document hits. This paper will discuss the motivation for and the capabilities of Buddy.

  5. Computational design of fused heterocyclic energetic materials

    NASA Astrophysics Data System (ADS)

    Tsyshevskiy, Roman; Pagoria, Philip; Batyrev, Iskander; Kuklja, Maija

    A continuous traditional search for effective energetic materials is often based on a trial and error approach. Understanding of fundamental correlations between the structure and sensitivity of the materials remains the main challenge for design of novel energetics due to the complexity of the behavior of energetic materials. State of the art methods of computational chemistry and solid state physics open new compelling opportunities in simulating and predicting a response of the energetic material to various external stimuli. Hence, theoretical and computational studies can be effectively used not only for an interpretation of sensitivity mechanisms of widely used explosives, but also for identifying criteria for material design prior to its synthesis and experimental characterization. We report here, how knowledge on thermal stability of recently synthesized materials of LLM series is used for design of novel fused heterocyclic energetic materials, including DNBTT (2,7-dinitro-4H,9H-bis([1, 2, 4"]triazolo)[1,5-b:1',5'-e][1, 2, 4, 5]tetrazine), compound with high thermal stability, which is on par or better than that of TATB. This research is supported by ONR (Grant N00014-12-1-0529), NSF XSEDE resources (Grant DMR-130077) and DOE NERSC resources (Contract DE-AC02-05CH11231).

  6. Carbon Nanotube Network Anti-fuses

    NASA Astrophysics Data System (ADS)

    Araujo, Paulo; Liao, Albert; Rodriguez-Nieva, Joaquin; Barros, Eduardo; Jung, Hyun; Hao, Ji; Jung, Yung; Dresselhaus, Mildred

    2014-03-01

    Copper interconnects are known to fail from electromigration at ~106 A/cm2. However, to continue aggressive scaling in integrated circuits (ICs), new materials that can carry much higher current densities will be required. For this reason, Carbon nanotubes (CNTs), which can carry up to 109 A/cm2, are a promising replacement. We discover that after Joule breakdown, CNTs can be healed by applying a healing voltage VH. Such a technology could be useful to repair failed interconnects, creating anti-fuses for field programmable gate array (FPGA) or memory technology. We fabricate a CNT network using a dip-coating method and then we sweep a voltage across the device until the CNT network undergoes Joule breakdown, creating a physical gap (of ~ 10-40 nm) within the network. Making hysteretic I - V sweeps, we observe a sudden increase in current at a voltage ~50 - 80 % of the breakdown voltage VBD. We can reliably break and heal the device multiple times. We also observe the Raman coalescence induced mode (CIM), which is characteristic of sp hybridized carbon chains, after the breaking and healing process. According to our analysis, we conclude that the formation of carbon chains is key to promote the electrical restoration of the broken CNT network.

  7. Future ultraviolet experiments, including FUSE/COLUMBUS

    NASA Technical Reports Server (NTRS)

    Boggess, A.

    1984-01-01

    Several new facilities for ultraviolet astronomy are under construction or study for launch within the coming decade. These include the Hubble Space Telescope to be launched in 1986 with instruments for spectroscopy, imaging, and photopolarimetry in the ultraviolet; the ASTRO Spacelab payload, also to be launched in 1986 with a similar range of instrumentation; STARLAB, a combined Canadian, Australian and U.S. mission concentrating primarily on imagery; and the Far Ultraviolet Spectroscopic Explorer (FUSE), which was renamed COLUMBUS. COLUMBUS is currently under study by NASA and ESA as a future joint mission for spectroscopic studies of astrophysical plasmas covering a temperature range from approximately 10 to the 3rd power to approximately 10 to the 7th power k. In order to achieve this objective, the optics should be optimized for wavelengths below 1200 Angstroms, with a total wavelength range from approximately 2000 to approximately 100 Angstroms. The operational concept will be based on experience with IUE, but changes in communications techniques since IUE was designed suggest some interesting new approaches to observing.

  8. Laser plasma interactions in fused silica cavities

    SciTech Connect

    Zeng, Xianzhong; Mao, Xianglei; Mao, Samuel S.; Yoo, Jong H.; Greif, Ralph; Russo, Richard E.

    2003-06-24

    The effect of laser energy on formation of a plasma inside a cavity was investigated. The temperature and electron number density of laser-induced plasmas in a fused silica cavity were determined using spectroscopic methods, and compared with laser ablation on a flat surface. Plasma temperature and electron number density during laser ablation in a cavity with aspect ratio of 4 increased faster with irradiance after the laser irradiance reached a threshold of 5 GW/cm{sup 2}. The threshold irradiance of particulate ejection was lower for laser ablation in a cavity compared with on a flat surface; the greater the cavity aspect ratio, the lower the threshold irradiance. The ionization of silicon becomes saturated and the crater depths were increased approximately by an order of magnitude after the irradiance reached the threshold. Phase explosion was discussed to explain the large change of both plasma characteristics and mass removal when irradiance increased beyond a threshold value. Self-focusing of the laser beam was discussed to be responsible for the decrease of the threshold in cavities.

  9. 1,3-Diferrocenyl-1,3-alkadienes in diene synthesis reactions

    SciTech Connect

    Pushin, A.N.; Klimova, E.I.; Sazanova, V.A.

    1987-11-10

    Stable 1,3-diferrocenyl-1,3-alkadienes, which form Diels-Alder adducts with N-substituted maleimides, have been prepared. Methyldiferrocenylbutadien participates in a cycloaddition reaction less readily than 1,3-diferrocenyl-1,3-butadiene. Adducts of 1,3-diferrocenyl-1,3-butadiene with N-substituted maleimides are dehydrogenated on Al/sub 2/O/sub 3/ or SiO/sub 2/ with subsequent formation of cyclohexadiene and benzene derivatives; protonation-deprotonation induces isomerization with transposition of the double bond.

  10. 21 CFR 1.3 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... REGULATIONS General Provisions § 1.3 Definitions. (a) Labeling includes all written, printed, or graphic... graphic matter on the immediate container of any article, or any such matter affixed to any...

  11. 21 CFR 1.3 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... REGULATIONS § 1.3 Definitions. (a) Labeling includes all written, printed, or graphic matter accompanying an... delivery in interstate commerce. (b) Label means any display of written, printed, or graphic matter on...

  12. HANSF 1.3 user's manual

    SciTech Connect

    PLYS, M.G.

    1999-05-21

    The HANSF analysis tool is an integrated model considering phenomena inside a multi-canister overpack (MCO) spent nuclear fuel container such as fuel oxidation, convective and radiative heat transfer, and the potential for fission product release. It may be used for all phases of spent fuel disposition including cold vacuum drying, transportation, and storage. This manual reflects HANSF version 1.3, a revised version of version 1.2a. HANSF 1.3 was written to add new models for axial nodalization, add new features for ease of usage, and correct errors. HANSF 1.3 is intended for use on personal computers such as IBM-compatible machines with Intel processors running under a DOS-type operating system. HANSF 1.3 is known to compile under Lahey TI and Digital Visual FORTRAN, Version 6.0, but this does not preclude operation in other environments.

  13. Perfluorinated chemicals in surface waters and sediments from northwest Georgia, USA, and their bioaccumulation in Lumbriculus variegatus

    USGS Publications Warehouse

    Lasier, Peter J.; Washington, John W.; Hassan, Sayed M.; Jenkins, Thomas M.

    2011-01-01

    Concentrations of perfluorinated chemicals (PFCs) were measured in surface waters and sediments from the Coosa River watershed in northwest Georgia, USA, to examine their distribution downstream of a suspected source. Samples from eight sites were analyzed using liquid chromatography-tandem mass spectrometry. Sediments were also used in 28-d exposures with the aquatic oligochaete, Lumbriculus variegatus, to assess PFC bioaccumulation. Concentrations of PFCs in surface waters and sediments increased significantly below a land-application site (LAS) of municipal/industrial wastewater and were further elevated by unknown sources downstream. Perfluorinated carboxylic acids (PFCAs) with eight or fewer carbons were the most prominent in surface waters. Those with 10 or more carbons predominated sediment and tissue samples. Perfluorooctane sulfonate (PFOS) was the major homolog in contaminated sediments and tissues. This pattern among sediment PFC concentrations was consistent among sites and reflected homolog concentrations emanating from the LAS. Concentrations of PFCs in oligochaete tissues revealed patterns similar to those observed in the respective sediments. The tendency to bioaccumulate increased with PFCA chain length and the presence of the sulfonate moiety. Biota-sediment accumulation factors indicated that short-chain PFCAs with fewer than seven carbons may be environmentally benign alternatives in aquatic ecosystems; however, sulfonates with four to seven carbons may be as likely to bioaccumulate as PFOS.

  14. Light-induced reversible modification of the work function of a new perfluorinated biphenyl azobenzene chemisorbed on Au (111).

    PubMed

    Masillamani, Appan Merari; Osella, Silvio; Liscio, Andrea; Fenwick, Oliver; Reinders, Federica; Mayor, Marcel; Palermo, Vincenzo; Cornil, Jérôme; Samorì, Paolo

    2014-08-01

    We describe the synthesis of a novel biphenyl azobenzene derivative exhibiting: (i) a protected thiol anchoring group in the α-position to readily form self-assembled monolayers (SAMs) on Au surfaces; and (ii) a terminal perfluorinated benzene ring in the ω-position to modify the surface properties. The design of this molecule ensured both an efficient in situ photoswitching between the trans and cis isomers when chemisorbed on Au(111), due to the presence of a biphenyl bridge between the thiol protected anchoring group and the azo dye, and a significant variation of the work function of the SAM in the two isomeric states, induced by the perfluorinated phenyl head group. By exploiting the light responsive nature of the chemisorbed molecules, it is possible to dynamically modify in situ the work function of the SAM-covered electrode, as demonstrated both experimentally and by quantum-chemical calculations, revealing changes in work function up to 220 meV. These findings are relevant for tuning the work function of metallic electrodes, and hence to dynamically modulate charge injection at metal-semiconductor interfaces for organic opto-electronic applications.

  15. Mechanical behavior of silica optical fibers coated with low-index low-surface energy perfluorinated polymer

    NASA Astrophysics Data System (ADS)

    Wojcik, Anna B.; Matthewson, M. John; Klein, Lisa C.; Foy, Paul R.; Snitzer, Elias; Wong, Ka Pak

    1996-01-01

    Two formulations based on perfluorinated polymer were prepared for use as UV-curable optical cladding for silica fibers. In the first formulation an adhesion promoting agent based on fluoroacrylate resin was synthesized and mixed with the experimental product Defensa 7702++ in order to promote wetting and chemical adhesion to the silica fibers. In the second formulation, wetting and physical adhesion between the liquid coating and the silica fibers were achieved by increasing the viscosity of the starting coating by addition of unsaturated perfluorinated polymer into Defensa. Both formulations were used as primary coatings on dual coated silica optical fibers. The mechanical behavior of the formulations was characterized by the strip test, the pull-out test and zero stress aging in 90 degrees Celsius pH 7 buffer. The results show that both formulations exhibit better wetting-adhesion characteristics than unmodified starting coating and that the strength degradation during zero- stress aging was lower for the fiber coated with the formulation of higher viscosity.

  16. A Novel Way To Identify Precursors That Degrade To Perfluorinated Compounds In Activated Sludge Using Ion-Trap Time-Of-Flight Mass Spectrometry

    EPA Science Inventory

    An increasing number of studies have been conducted to investigate the environmental distribution of perfluorinated alkyl compounds (PFCs), many of which are known to be toxic in laboratory animals. Despite growing public concerns, fate and transport of PFCs are little known. M...

  17. Workers at CCAS attach solar panel to FUSE satellite.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Workers at Hangar AE, Cape Canaveral Air Station (CCAS), check NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite after moving it from the scaffolding behind it. FUSE was developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., to investigate the origin and evolution of the lightest elements in the universe - hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum. The satellite is targeted for launch June 23 from Launch Pad 17A, CCAS, aboard a Boeing Delta II rocket.

  18. Capturing the Fused-Pentagon C74 by Stepwise Chlorination.

    PubMed

    Gao, Cong-Li; Abella, Laura; Tan, Yuan-Zhi; Wu, Xin-Zhou; Rodríguez-Fortea, Antonio; Poblet, Josep M; Xie, Su-Yuan; Huang, Rong-Bin; Zheng, Lan-Sun

    2016-07-18

    As a bridge to connect medium-sized fullerenes, fused-pentagon C74 is still missing heretofore. Of 14 246 possible isomers, the first fused-pentagon C74 with the Fowler-Manolopoulos code of 14 049 was stabilized as C74Cl10 in the chlorine-involving carbon arc. The structure of C74Cl10 was identified by X-ray crystallography. The stabilization of pristine fused-pentagon C74 by stepwise chlorination was clarified in both theoretical simulation with density functional theory calculations and experimental fragmentation with multistage mass spectrometry. PMID:27341488

  19. Fused xanthone derivatives as antiproliferative agents.

    PubMed

    Pouli, Nicole; Marakos, Panagiotis

    2009-01-01

    Xanthones have been isolated from several natural sources, mainly belonging in Guttiferae and Gentianaceae families as secondary plant metabolites and many of them are endowed with diverse pharmacological properties. We have focused in the study of cytotoxic fused xanthone derivatives, having in mind that some furano- and pyranoxanthone natural products are particularly interesting, in terms of cytotoxic potency and novelty in their mechanism of action and could serve as lead compounds for the development of clinically effective anticancer agents. In this review, a general classification has been attempted based on the type of ring fusion, in such a way that natural compounds as well as synthetic derivatives are discussed. The furanoxanthone psorospermin is a highly promising isolated xanthone derivative exhibiting significant cytotoxicity through a novel mechanism of action, being an irreversible topoisomerase II poison and it was selected for further development as an antineoplastic agent. An important number of pyranoxanthones have been synthesized using as lead compound the acridone alkaloid acronycine. Adducts on the double bond of these compounds provided cytotoxic derivatives possessing cell-cycle selectivity. The synthesis of pyranoxanthones bearing aminosubstituted side-chains resulted in compounds that exhibit markedly improved cytotoxicity towards leukemic and solid tumor cell lines. Azabioisosters of the aminoderivatives exhibit solid tumor selectivity whereas additional pyrazole or/and benzene ring fusion has been incorporated into the xanthone skeleton and resulted in compounds with promising activity, which retain full antiproliferative activity against P-glycoprotein-overexpressing cells. Gambogic acid, a highly effective anticancer drug candidate with low toxicity to normal tissue, together with structurally related representative analogues are also mentioned. PMID:19149484

  20. Nuclear Magnetic Resonance Studies of Water in Perfluorinated Ion Exchange Membranes.

    NASA Astrophysics Data System (ADS)

    Chen, Rensheng

    Perfluorinated ion-exchange membranes such as NAFION (DuPont) serve as both electrolyte and separators employed in fuel cells. The presence of the water in these membranes is critical to fuel cell operation. Water molecular diffusion and charge transport across the membrane are correlated. Through the availability of water isotopically enriched in deuterium or ^ {17} O, nuclear magnetic resonance (NMR) can be employed to study molecular dynamics by utilizing quadrupolar nuclei as probes. In this thesis, Deuteron and oxygen-17 NMR measurements in NAFION-117 membranes with variable water (D_{2}O or H_ {2}^{17}O) content (3 ~18% by weight) have been carried out. Measurements were taken at variable temperature (room T down to 115 K), high pressure (up to 0.25 GPa), and on stretched samples. One of the main results concerns the observation of anisotropic molecular motion in the membrane plane, with dramatic enhancement of the anisotropy in modestly stretched membranes. Glassy behavior of the water domains at low temperature is evidenced by the specific nature of the ^{2}H NMR line shapes at 109 K. Activation energies extracted from both ^{2}H and ^ {17}O spin-lattice relaxation data exhibit a steady increase with increasing water content. Activation volumes extracted from both ^{1} H and ^{2}H T _{1} pressure dependence show a decrease with increasing water content, at room temperature. Analysis of these observations suggests a water cluster model for water organization in NAFION membranes. The relatively free water and motionally restricted (by interaction with the polymer host) water exchange each other rapidly yielding an averaged response at room T, while the hydrogen bonds become more rigid at low temperature. Deuteron and oxygen -17 NMR studies of NAFION-117 containing either deuterated methanol (CH_{3}OD) or oxygen-17 enriched methanol (CH_{3 } ^{17}OH) demonstrate that the methanol molecular motion in NAFION-117 is considerably faster than for water in NAFION

  1. Does wet precipitation represent local and regional atmospheric transportation by perfluorinated alkyl substances?

    PubMed

    Taniyasu, Sachi; Yamashita, Nobuyoshi; Moon, Hyo-Bang; Kwok, Karen Y; Lam, Paul K S; Horii, Yuichi; Petrick, Gert; Kannan, Kurunthachalam

    2013-05-01

    Perfluorinated alkyl substances (PFASs) have been found widely in the environment including remote marine locations. The mode of transport of PFASs to remote marine locations is a subject of considerable scientific interest. Assessment of distribution of PFASs in wet precipitation samples (i.e., rainfall and snow) collected over an area covering continental, coastal, and open ocean will enable an understanding of not only the global transport but also the regional transport of PFASs. Nevertheless, it is imperative to examine the representativeness and suitability of wet precipitation matrixes to allow for drawing conclusions on the transport PFASs. In this study, we collected wet precipitation samples including rainfall, surface snow, and snow core from several locations in Japan to elucidate the suitability of these matrixes for describing local and regional transport of PFASs. Rain water collected at various time intervals within a single rainfall event showed high fluxes of PFASs in the first 1-mm deposition. The scavenging rate of PFASs by wet deposition varied depending on the fluorocarbon chain length of PFAS. The depositional fluxes of PFASs measured for continental (Tsukuba, Japan) and open ocean (Pacific Ocean, 1000km off Japanese coast) locations were similar, on the order of a few nanograms per square meter. The PFAS profiles in "freshly" deposited and "aged" (deposited on the ground for a few days) snow samples taken from the same location varied considerably. The freshly deposited snow represents current atmospheric profiles of PFASs, whereas the aged snow sample reflects sequestration of local sources of PFASs from the atmosphere. Post-depositional modifications in PFAS profiles were evident, suggesting reactions of PFASs on snow/ice surface. Transformation of precursor chemicals such as fluorotelomer alcohols into perfluoroalkylcarboxylates is evident on snow surface. Snow cores have been used to evaluate time trends of PFAS contamination in remote

  2. Serum concentrations of perfluorinated compounds (PFC) among selected populations of children and Adults in California

    PubMed Central

    Wu, Xiangmei (May); Bennett, Deborah H.; Calafat, Antonia M.; Kato, Kayoko; Strynar, Mark; Andersen, Erik; Moran, Rebecca E.; Tancredi, Daniel J.; Tulve, Nicolle S.; Hertz-Picciotto, Irva

    2016-01-01

    Perfluorinated compounds (PFCs) have been widely used in industrial applications and consumer products. Their persistent nature and potential health impacts are of concern. Given the high cost of collecting serum samples, this study is to understand whether we can quantify PFC serum concentrations using factors extracted from questionnaire responses and indirect measurements, and whether a single serum measurement can be used to classify an individual’s exposure over a one-year period. The study population included three demographic groups: young children (2–8 years old) (N=67), parents of young children (<55 years old) (N=90), and older adults (>55 years old) (N=59). PFC serum concentrations, house dust concentrations, and questionnaires were collected. The geometric mean of perfluorooctane sulfonic acid (PFOS) was highest for the older adults. In contrast, the geometric mean of perfluorooctanoic acid (PFOA) was highest for children. Serum concentrations of the parent and the child from the same family were moderately correlated (Spearman correlation (r)=0.26–0.79, p<0.05), indicating common sources within a family. For adults, age, having occupational exposure or having used fire extinguisher, frequencies of consuming butter/margarine, pork, canned meat entrées, tuna and white fish, freshwater fish, and whether they ate microwave popcorn were significantly positively associated with serum concentrations of individual PFCs. For children, residential dust concentrations, frequency of wearing waterproof clothes, frequency of having canned fish, hotdogs, chicken nuggets, French fries, and chips, and whether they ate microwave popcorn were significant positive predictors of individual PFC serum concentrations. In addition, the serum concentrations collected in a subset of young children (N=20) and the parents (N=42) one year later were strongly correlated (r=0.68–0.98, p<0.001) with the levels measured at the first visits, but showed a decreasing trend

  3. Levels, temporal trends, and tissue distribution of perfluorinated surfactants in freshwater fish from Asian countries.

    PubMed

    Murakami, Michio; Adachi, Nozomi; Saha, Mahua; Morita, Chiaki; Takada, Hideshige

    2011-11-01

    Perfluorinated surfactants (PFSs) in Asian freshwater fish species were analyzed to investigate tissue distribution, temporal trends, extent of pollution, and level of PFS exposure through food intake. Freshwater fish species, namely carp, snakehead, and catfish, were collected in Japan, Vietnam, India, Malaysia, and Thailand, and 10 PFSs, including perfluorooctanesulfonate (PFOS) and perfluorooctanoate, were analyzed by liquid chromatography-tandem mass spectrometry. PFSs in carp in Tokyo were more concentrated in kidneys (Σ10 PFSs = 257 ± 95 ng/g wet weight [ww]) and livers (119 ± 36 ng/g ww) than in ovaries (43 ± 2 ng/g ww) and muscles (24 ± 17 ng/g ww). Concentrations of PFOS and its precursor, perfluorooctane sulfonamide, in livers of carp and in waters in Tokyo showed a dramatic decrease during the last decade, probably because of 3 M's phasing-out of the manufacture of perfluorooctanesulfonyl-fluoride-based products in 2000. In contrast, continuing contamination by long-chain perfluorocarboxylates (PFCAs) with ≥ 9 fluorinated carbons was seen in multiple media, suggesting that these compounds continue to be emitted. PFS concentrations in freshwater fish species in tropical Asian countries were generally lower than those in developed countries, such as Japan, e.g., for PFOS in muscle, Vietnam < 0.05-0.3 ng/g ww; India < 0.05-0.2 ng/g ww; Malaysia < 0.05-0.2 ng/g ww; Thailand < 0.05 ng/g ww; and Japan (Tokyo) = 5.1-22 ng/g ww. Daily intake of short-chain PFCAs with ≤ 8 fluorinated carbons from freshwater fish species in Japan was approximately one order of magnitude lower than that from drinking water, whereas daily intake of PFOS and long-chain PFCAs with ≥ 9 fluorinated carbons from freshwater fish species was comparable with or greater than that from drinking water. Because the risk posed by exposure to these compounds through intake of fish species is a matter of concern, we recommend the continued monitoring of PFS levels in Asian developing

  4. Theoretical study of the decomposition pathways and products of C5- perfluorinated ketone (C5 PFK)

    NASA Astrophysics Data System (ADS)

    Fu, Yuwei; Wang, Xiaohua; Li, Xi; Yang, Aijun; Han, Guohui; Lu, Yanhui; Wu, Yi; Rong, Mingzhe

    2016-08-01

    Due to the high global warming potential (GWP) and increasing environmental concerns, efforts on searching the alternative gases to SF6, which is predominantly used as insulating and interrupting medium in high-voltage equipment, have become a hot topic in recent decades. Overcoming the drawbacks of the existing candidate gases, C5- perfluorinated ketone (C5 PFK) was reported as a promising gas with remarkable insulation capacity and the low GWP of approximately 1. Experimental measurements of the dielectric strength of this novel gas and its mixtures have been carried out, but the chemical decomposition pathways and products of C5 PFK during breakdown are still unknown, which are the essential factors in evaluating the electric strength of this gas in high-voltage equipment. Therefore, this paper is devoted to exploring all the possible decomposition pathways and species of C5 PFK by density functional theory (DFT). The structural optimizations, vibrational frequency calculations and energy calculations of the species involved in a considered pathway were carried out with DFT-(U)B3LYP/6-311G(d,p) method. Detailed potential energy surface was then investigated thoroughly by the same method. Lastly, six decomposition pathways of C5 PFK decomposition involving fission reactions and the reactions with a transition states were obtained. Important intermediate products were also determined. Among all the pathways studied, the favorable decomposition reactions of C5 PFK were found, involving C-C bond ruptures producing Ia and Ib in pathway I, followed by subsequent C-C bond ruptures and internal F atom transfers in the decomposition of Ia and Ib presented in pathways II + III and IV + V, respectively. Possible routes were pointed out in pathway III and lead to the decomposition of IIa, which is the main intermediate product found in pathway II of Ia decomposition. We also investigated the decomposition of Ib, which can undergo unimolecular reactions to give the formation

  5. Occurrence of perfluorinated compounds in raw water from New Jersey public drinking water systems.

    PubMed

    Post, Gloria B; Louis, Judith B; Lippincott, R Lee; Procopio, Nicholas A

    2013-01-01

    Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were previously detected (≥ 4 ng/L) in 65% and 30%, respectively, of 23 New Jersey (NJ) public drinking water systems (PWS) sampled in 2006. We now report on a 2009 study of the occurrence of PFOA, PFOS, and eight other perfluorinated compounds (PFCs) in raw water samples from 30 intakes (18 groundwater and 12 surface water) from 29 additional NJ PWS. Between 1 and 8 PFCs were detected (≥ 5 ng/L) in 21 (70%) of 30 PWS samples at total PFC concentrations of 5-174 ng/L. Although PFOA was the most commonly detected PFC (57% of samples) and was found at the highest maximum concentration (100 ng/L), some of the higher levels of other PFCs were at sites with little or no PFOA. Perfluorononanoic acid was detected more frequently (30%) and at higher concentrations (up to 96 ng/L) than in raw or finished drinking water elsewhere, and it was found at several sites as the sole or predominant PFC, a pattern not reported in other drinking water studies. PFOS, perfluoropentanoic acid, and perfluorohexanoic acid were each detected in more than 20% of samples, while perfluoroheptanoic acid, perfluorobutane sulfonic acid, and perfluorohexane sulfonic acid were detected less frequently. Perfluorobutanoic acid was found only once (6 ng/L), and perfluorodecanoic acid was not detected. Total PFCs were highest in two reservoirs near an airfield; these were also the only sites with total perfluorosulfonic acids higher than total perfluorocarboxylic acids (PFCAs). PFC levels in raw and finished water from the same source were similar at those sites where both were tested. Five wells of two additional NJ PWS known to be contaminated with PFOA were also each sampled 4-9 times in 2010-13 for nine of the same PFCs. Total PFCs (almost completely PFCAs) at one of these PWS located near an industrial source of PFCs were higher than in any other PWS tested (up to 330 ng/L). These results show that multiple PFCs are

  6. Infant exposure of perfluorinated compounds: levels in breast milk and commercial baby food.

    PubMed

    Llorca, Marta; Farré, Marinella; Picó, Yolanda; Teijón, Marisa Lopez; Alvarez, Juan G; Barceló, Damià

    2010-08-01

    In this study, an analytical method to determine six perfluorinated compounds (PFCs) based on alkaline digestion and solid phase extraction (SPE) followed by liquid chromatography-quadrupole-linear ion trap mass spectrometry (LC-QqLIT-MS) was validated for the analysis of human breast milk, milk infant formulas and cereals baby food. The average recoveries of the different matrices were in general higher than 70% with a relative standard deviation (RSD) lower than 21% and method limits of detection (MLOD) ranging from 1.2 to 362 ng/L for the different compounds and matrices. The method was applied to investigate the occurrence of PFCs in 20 samples of human breast milk, and 5 samples of infant formulas and cereal baby food (3 brands of commercial milk infant formulas and 2 brands of cereals baby food). Breast milk samples were collected in 2008 from donors living in Barcelona city (Spain) on the 40 days postpartum. Perfluorooctanesulfonate (PFOS) and perfluoro-7-methyloctanoic acid (i,p-PFNA) were predominant being present in the 95% of breast milk samples. Perfluorooctanoic acid (PFOA) was quantified in 8 of the 20 breast milk samples at concentrations in the range of 21-907 ng/L. Commercial formulas and food were purchased also in 2009 from a retail store. The six PFCs were detected in all brands of milk infant formulas and cereals baby food analyzed, being perfluorodecanoic acid (PFDA), PFOS, PFOA and i,p-PFNA the compounds detected in higher concentrations (up to 1289 ng/kg). PFCs presence can be associated to possible migration from packaging and containers during production processes. Finally, based on estimated body weight and newborn intake, PFOS and PFOA daily intakes and risk indexes (RI) were estimated for the firsts 6 month of life. We found that ingestion rates of PFOS and PFOA, with exception of one breast milk sample did not exceed the tolerable daily intake (TDI) recommended by the EFSA. However, more research is needed in order to assess possible

  7. Polyfluorinated and perfluorinated chemicals in precipitation and runoff from cities across eastern and central China.

    PubMed

    Zhao, Lijie; Zhou, Meng; Zhang, Tao; Sun, Hongwen

    2013-02-01

    Twenty-three polychlorinated and perfluorinated compounds (PFCs) were investigated in water phase and particulate matters of 19 precipitation samples (18 snow samples and 1 rain sample) from different cities across eastern and central China collected in February 2010. The PFCs in samples of 9e precipitation events during more than half a year at 1 site in Tianjin and 6 successive samples during 1 precipitation event were measured to elucidate the change of PFC in precipitation. In addition, PFCs in 3 runoffs at different kinds of sites in Tianjin were compared with those in the corresponding precipitation. The results showed that the particulate matters separated from the precipitation contained undetectable PFCs. The total PFC concentration ranged between 4.7 and 152 ng L(-1) in water phase of the precipitation samples, with perfluorooctanoic acid (PFOA) being detected at all of the sampling sites and the dominant PFC at most of the sampling sites. Some potential precursors of environmentally concerned PFCs and their degradation intermediates were measured simultaneously, among which 6:2 fluorotelomer unsaturated carboxylic acid (6:2 FTUCA), 8:2 FTUCA, and  × (3, 4, 5, 7):3 acid [F(CF(2))xCH(2)CH(2)COOH] were measured for the first time in Chinese precipitations; however, their concentrations were all lower than the limits of detection except that 6:2 FTUCA and 8:2 FTUCA could be detected in 3 and 8 precipitation samples, respectively. No clear seasonal variation in PFC concentrations in precipitation was observed during half a year; however, a relatively greater average concentration of total PFCs was observed during winter and summer compared with spring. The concentration of individual PFCs showed an obvious descending trend in the successive samples of the precipitation event. PFOA and perfluorononanoic acid in runoffs collected from different sites showed the following similar pattern-gas station > highway > university campus-whereas the other

  8. Occurrence of perfluorinated compounds in raw water from New Jersey public drinking water systems.

    PubMed

    Post, Gloria B; Louis, Judith B; Lippincott, R Lee; Procopio, Nicholas A

    2013-01-01

    Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were previously detected (≥ 4 ng/L) in 65% and 30%, respectively, of 23 New Jersey (NJ) public drinking water systems (PWS) sampled in 2006. We now report on a 2009 study of the occurrence of PFOA, PFOS, and eight other perfluorinated compounds (PFCs) in raw water samples from 30 intakes (18 groundwater and 12 surface water) from 29 additional NJ PWS. Between 1 and 8 PFCs were detected (≥ 5 ng/L) in 21 (70%) of 30 PWS samples at total PFC concentrations of 5-174 ng/L. Although PFOA was the most commonly detected PFC (57% of samples) and was found at the highest maximum concentration (100 ng/L), some of the higher levels of other PFCs were at sites with little or no PFOA. Perfluorononanoic acid was detected more frequently (30%) and at higher concentrations (up to 96 ng/L) than in raw or finished drinking water elsewhere, and it was found at several sites as the sole or predominant PFC, a pattern not reported in other drinking water studies. PFOS, perfluoropentanoic acid, and perfluorohexanoic acid were each detected in more than 20% of samples, while perfluoroheptanoic acid, perfluorobutane sulfonic acid, and perfluorohexane sulfonic acid were detected less frequently. Perfluorobutanoic acid was found only once (6 ng/L), and perfluorodecanoic acid was not detected. Total PFCs were highest in two reservoirs near an airfield; these were also the only sites with total perfluorosulfonic acids higher than total perfluorocarboxylic acids (PFCAs). PFC levels in raw and finished water from the same source were similar at those sites where both were tested. Five wells of two additional NJ PWS known to be contaminated with PFOA were also each sampled 4-9 times in 2010-13 for nine of the same PFCs. Total PFCs (almost completely PFCAs) at one of these PWS located near an industrial source of PFCs were higher than in any other PWS tested (up to 330 ng/L). These results show that multiple PFCs are

  9. Roles of Rat Renal Organic Anion Transporters in Transporting Perfluorinated Carboxylates with Different Chain Lengths

    PubMed Central

    Weaver, Yi M.; Ehresman, David J.; Butenhoff, John L.; Hagenbuch, Bruno

    2010-01-01

    Perfluorinated carboxylates (PFCAs) are generally stable to metabolic and environmental degradation and have been found at low concentrations in environmental and biological samples. Renal clearance of PFCAs depends on chain length, species, and, in some cases, gender within species. While perfluoroheptanoate (C7) is almost completely eliminated renally in both male and female rats, renal clearance of perfluorooctanoate (C8) and perfluorononanoate (C9) is much higher in female rats. Perfluorodecanoate (C10) mainly accumulates in the liver for both genders. Therefore, we tested whether PFCAs with different chain lengths are substrates of rat renal transporters with gender-specific expression patterns. Inhibition of uptake of model substrates was measured for the basolateral organic anion transporter (Oat)1 and Oat3 and the apical Oat2, organic anion transporting polypeptide (Oatp)1a1, and Urat1 with 10μM PFCAs with chain lengths from 2 to 18 (C2–C18) carbons. Perfluorohexanoate (C6), C7, and C8 inhibited Oat1-mediated p-aminohippurate transport, with C7 being the strongest inhibitor. C8 and C9 were the strongest inhibitors for Oat3-mediated estrone-3-sulfate transport, while Oatp1a1-mediated estradiol-17β-glucuronide uptake was inhibited by C9, C10, and perflouroundecanoate (C11), with C10 giving the strongest inhibition. No strong inhibitors were found for Oat2 or Urat1. Kinetic analysis was performed for the strongest inhibitors. Oat1 transported C7 and C8 with Km values of 50.5 and 43.2μM, respectively. Oat3 transported C8 and C9 with Km values of 65.7 and 174.5μM, respectively. Oatp1a1-mediated transport yielded Km values of 126.4 (C8), 20.5 (C9), and 28.5μM (C10). These results suggest that Oat1 and Oat3 are involved in renal secretion of C7–C9, while Oatp1a1 can contribute to the reabsorption of C8 through C10, with highest affinities for C9 and C10. PMID:19915082

  10. Serum concentrations of perfluorinated compounds (PFC) among selected populations of children and adults in California.

    PubMed

    Wu, Xiangmei May; Bennett, Deborah H; Calafat, Antonia M; Kato, Kayoko; Strynar, Mark; Andersen, Erik; Moran, Rebecca E; Tancredi, Daniel J; Tulve, Nicolle S; Hertz-Picciotto, Irva

    2015-01-01

    Perfluorinated compounds (PFCs) have been widely used in industrial applications and consumer products. Their persistent nature and potential health impacts are of concern. Given the high cost of collecting serum samples, this study is to understand whether we can quantify PFC serum concentrations using factors extracted from questionnaire responses and indirect measurements, and whether a single serum measurement can be used to classify an individual's exposure over a one-year period. The study population included three demographic groups: young children (2-8 years old) (N=67), parents of young children (<55 years old) (N=90), and older adults (>55 years old) (N=59). PFC serum concentrations, house dust concentrations, and questionnaires were collected. The geometric mean of perfluorooctane sulfonic acid (PFOS) was highest for the older adults. In contrast, the geometric mean of perfluorooctanoic acid (PFOA) was highest for children. Serum concentrations of the parent and the child from the same family were moderately correlated (Spearman correlation (r)=0.26-0.79, p<0.05), indicating common sources within a family. For adults, age, having occupational exposure or having used fire extinguisher, frequencies of consuming butter/margarine, pork, canned meat entrées, tuna and white fish, freshwater fish, and whether they ate microwave popcorn were significantly positively associated with serum concentrations of individual PFCs. For children, residential dust concentrations, frequency of wearing waterproof clothes, frequency of having canned fish, hotdogs, chicken nuggets, French fries, and chips, and whether they ate microwave popcorn were significant positive predictors of individual PFC serum concentrations. In addition, the serum concentrations collected in a subset of young children (N=20) and the parents (N=42) one year later were strongly correlated (r=0.68-0.98, p<0.001) with the levels measured at the first visits, but showed a decreasing trend. Children had

  11. Polyfluorinated and perfluorinated chemicals in precipitation and runoff from cities across eastern and central China.

    PubMed

    Zhao, Lijie; Zhou, Meng; Zhang, Tao; Sun, Hongwen

    2013-02-01

    Twenty-three polychlorinated and perfluorinated compounds (PFCs) were investigated in water phase and particulate matters of 19 precipitation samples (18 snow samples and 1 rain sample) from different cities across eastern and central China collected in February 2010. The PFCs in samples of 9e precipitation events during more than half a year at 1 site in Tianjin and 6 successive samples during 1 precipitation event were measured to elucidate the change of PFC in precipitation. In addition, PFCs in 3 runoffs at different kinds of sites in Tianjin were compared with those in the corresponding precipitation. The results showed that the particulate matters separated from the precipitation contained undetectable PFCs. The total PFC concentration ranged between 4.7 and 152 ng L(-1) in water phase of the precipitation samples, with perfluorooctanoic acid (PFOA) being detected at all of the sampling sites and the dominant PFC at most of the sampling sites. Some potential precursors of environmentally concerned PFCs and their degradation intermediates were measured simultaneously, among which 6:2 fluorotelomer unsaturated carboxylic acid (6:2 FTUCA), 8:2 FTUCA, and  × (3, 4, 5, 7):3 acid [F(CF(2))xCH(2)CH(2)COOH] were measured for the first time in Chinese precipitations; however, their concentrations were all lower than the limits of detection except that 6:2 FTUCA and 8:2 FTUCA could be detected in 3 and 8 precipitation samples, respectively. No clear seasonal variation in PFC concentrations in precipitation was observed during half a year; however, a relatively greater average concentration of total PFCs was observed during winter and summer compared with spring. The concentration of individual PFCs showed an obvious descending trend in the successive samples of the precipitation event. PFOA and perfluorononanoic acid in runoffs collected from different sites showed the following similar pattern-gas station > highway > university campus-whereas the other

  12. Does wet precipitation represent local and regional atmospheric transportation by perfluorinated alkyl substances?

    PubMed

    Taniyasu, Sachi; Yamashita, Nobuyoshi; Moon, Hyo-Bang; Kwok, Karen Y; Lam, Paul K S; Horii, Yuichi; Petrick, Gert; Kannan, Kurunthachalam

    2013-05-01

    Perfluorinated alkyl substances (PFASs) have been found widely in the environment including remote marine locations. The mode of transport of PFASs to remote marine locations is a subject of considerable scientific interest. Assessment of distribution of PFASs in wet precipitation samples (i.e., rainfall and snow) collected over an area covering continental, coastal, and open ocean will enable an understanding of not only the global transport but also the regional transport of PFASs. Nevertheless, it is imperative to examine the representativeness and suitability of wet precipitation matrixes to allow for drawing conclusions on the transport PFASs. In this study, we collected wet precipitation samples including rainfall, surface snow, and snow core from several locations in Japan to elucidate the suitability of these matrixes for describing local and regional transport of PFASs. Rain water collected at various time intervals within a single rainfall event showed high fluxes of PFASs in the first 1-mm deposition. The scavenging rate of PFASs by wet deposition varied depending on the fluorocarbon chain length of PFAS. The depositional fluxes of PFASs measured for continental (Tsukuba, Japan) and open ocean (Pacific Ocean, 1000km off Japanese coast) locations were similar, on the order of a few nanograms per square meter. The PFAS profiles in "freshly" deposited and "aged" (deposited on the ground for a few days) snow samples taken from the same location varied considerably. The freshly deposited snow represents current atmospheric profiles of PFASs, whereas the aged snow sample reflects sequestration of local sources of PFASs from the atmosphere. Post-depositional modifications in PFAS profiles were evident, suggesting reactions of PFASs on snow/ice surface. Transformation of precursor chemicals such as fluorotelomer alcohols into perfluoroalkylcarboxylates is evident on snow surface. Snow cores have been used to evaluate time trends of PFAS contamination in remote

  13. Perfluorinated compounds in coastal waters of Hong Kong, South China, and Korea.

    PubMed

    So, M K; Taniyasu, S; Yamashita, N; Giesy, J P; Zheng, J; Fang, Z; Im, S H; Lam, Paul K S

    2004-08-01

    Perfluorinated compounds (PFCs), such as perfluorooctanesulfonate (PFOS) and related compounds, have recently been identified in the environment. PFOS, the terminal degradation product of many of the PFCs, has been found globally in many wildlife species, as well as open ocean waters, even in remote regions far from sources. In this study, a solid-phase extraction procedure coupled with high-performance liquid chromatography interfaced to high-resolution mass spectrometry was used to isolate, identify, and quantify small concentrations of PFCs in seawater. These techniques were applied to investigate the local sources of PFCs in several industrialized areas of Asia and provide information on how the PFCs are circulated by coastal currents. Ranges of concentrations of PFOS in coastal seawaters of Hong Kong, the Pearl River Delta, including the South China Sea, and Korea were 0.09-3.1, 0.02-12, and 0.04-730 pg/mL, respectively, while those of perfluorooctanoic acid (PFOA) were 0.73-5.5, 0.24-16, and 0.24-320 pg/mL, respectively. Potential sources of PFCs include major industrialized areas along the Pearl River Delta of southern China and major cities of Korea, which are several of the fastest growing industrial and economic regions in the world. Detectable concentrations of PFOS and PFOA in waters of southern China were similar to those in the coastal marine environment of Japan and certain regions in Korea. Concentrations of PFCs in several locations in Korean waters were 10-100-fold greater than those in the other locations on which we report here. The spatial and seasonal variations in PFC concentrations in surface seawaters in the Pearl River Delta and South China Sea indicate the strong influence of the Pearl River discharge on the magnitude and extent of PFC contamination in southern China. All of the concentrations of PFOS were less than those that would be expected to cause adverse effects to aquatic organisms or their predators except for one location in

  14. Radiation Effects on Fused Biconical Taper Wavelength Division Multiplexers

    NASA Technical Reports Server (NTRS)

    Gutierrez, Roman C.; Swift, Gary M.; Dubovitsky, Serge; Bartman, Randall K.; Barnes, Charles E.; Dorsky, Leonard

    1994-01-01

    The effects of radiation on fused biconical taper wavelength division multiplexers are presented. A theoretical model indicates that index changes in the fiber are primarily responsible for the degradation of these devices.

  15. Unsymmetrical pyrene-fused phthalocyanine derivatives: synthesis, structure, and properties.

    PubMed

    Pan, Houhe; Chen, Chao; Wang, Kang; Li, Wenjun; Jiang, Jianzhuang

    2015-02-16

    Novel pyrene-fused unsymmetrical phthalocyanine derivatives 2,3,9,10,16,17-hexakis(2,6-dimethylphenoxy)-22,25-diaza(2,7-di-tert-butylpyrene)[4,5]phthalocyaninato zinc complex Zn[Pc(Pz-pyrene)(OC8 H9 )6 ] (1) and 2,3,9,10-tra(2,6-dimethylphenoxy)-15,18,22,25-traza(2,7-di-tert-butylpyrene)[4,5]phthalocyaninato zinc compound Zn[Pc(Pz-pyrene)2 (OC8 H9 )4 ] (2) were isolated for the first time. These unsymmetrical pyrene-fused phthalocyanine derivatives have been characterized by a wide range of spectroscopic and electrochemical methods. In particular, the pyrene-fused phthalocyanine structure was unambiguously revealed on the basis of single crystal X-ray diffraction analysis of 1, representing the first structurally characterized phthalocyanine derivative fused with an aromatic moiety larger than benzene.

  16. Quantification of residual stress from photonic signatures of fused silica

    NASA Astrophysics Data System (ADS)

    Cramer, K. Elliott; Hayward, Maurice; Yost, William T.

    2014-02-01

    A commercially available grey-field polariscope (GFP) instrument for photoelastic examination is used to assess impact damage inflicted upon the outer-most pane of Space Shuttle windows made from fused silica. A method and apparatus for calibration of the stress-optic coefficient using four-point bending is discussed. The results are validated on known material (acrylic) and are found to agree with literature values to within 6%. The calibration procedure is then applied to fused-silica specimens and the stress-optic coefficient is determined to be 2.43 ± 0.54 × 10-12 Pa-1. Fused silica specimens containing impacts artificially made at NASA's Hypervelocity Impact Technology Facility (HIT-F), to simulate damage typical during space flight, are examined. The damage sites are cored from fused silica window carcasses and examined with the GFP. The calibrated GFP measurements of residual stress patterns surrounding the damage sites are presented.

  17. Boeing Delta II rocket for FUSE launch arrives at CCAS

    NASA Technical Reports Server (NTRS)

    1999-01-01

    After its arrival at Launch Pad 17A, Cape Canaveral Air Station (CCAS), the first stage of a Boeing Delta II rocket is raised to a vertical position. The rocket is targeted to launch NASA's Far Ultraviolet Spectroscopic Explorer (FUSE), developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md. FUSE will investigate the origin and evolution of the lightest elements in the universe, hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum. FUSE is scheduled to be launched June 23 at CCAS.

  18. Boeing Delta II rocket for FUSE launch arrives at CCAS

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At Launch Pad 17A, Cape Canaveral Air Station (CCAS), the first stage of a Boeing Delta II rocket is raised for its journey up the launch tower. The rocket is targeted to launch NASA's Far Ultraviolet Spectroscopic Explorer (FUSE), developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md. FUSE will investigate the origin and evolution of the lightest elements in the universe, hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum. FUSE is scheduled to be launched June 23 at CCAS.

  19. Astronaut Hoffman replaces fuse plugs on Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Astronaut Jeffrey A. Hoffman sees to the replacement of fuse plugs on the Hubble Space Telescope (HST) during the first of five space walks. Thunderclouds are all that is visible on the dark earth in the background.

  20. Boeing Delta II rocket for FUSE launch arrives at CCAS

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At Launch Pad 17A, Cape Canaveral Air Station (CCAS), the first stage of a Boeing Delta II rocket is ready to be lifted into the tower. The rocket is targeted to launch NASA's Far Ultraviolet Spectroscopic Explorer (FUSE), developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md. FUSE will investigate the origin and evolution of the lightest elements in the universe,hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum. FUSE is scheduled to be launched June 23 at CCAS.

  1. Workers at CCAS attach solar panel to FUSE satellite.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At Hangar AE, Cape Canaveral Air Station (CCAS), workers get ready to move a solar panel to be attached to NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite in the background. FUSE was developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., to investigate the origin and evolution of the lightest elements in the universe - hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum. FUSE is targeted for launch June 23 from Launch Pad 17A, CCAS, aboard a Boeing Delta II rocket.

  2. Backreflected radiation due to a propagating fiber fuse.

    PubMed

    Abedin, Kazi S; Nakazawa, Masataka; Miyazaki, Tetsuya

    2009-04-13

    The properties of backreflected light due to voids in a fiber fuse were studied using optical coherence-domain reflectometry of a damaged fiber and real-time monitoring of the electrical (RF) and optical frequency spectrum. Light reflected backward at the interface of a propagating fiber fuse acquired low-frequency broadband amplitude modulation, which can be detected remotely at the source end, using an RF spectrum analyzer. For the light backreflected during propagation of a fuse, we derived an analytical expression that well explained the spectral features observed experimentally in the RF spectrum. Finally, a novel method that allowed us to rapidly terminate the fuse propagation (in a few milliseconds) is also shown.

  3. Technical report on galvanic cells with fused-salt electrolytes

    NASA Technical Reports Server (NTRS)

    Cairns, E. J.; Crouthamel, C. E.; Fischer, A. K.; Foster, M. S.; Hesson, J. C.; Johnson, C. E.; Shimotake, H.; Tevebaugh, A. D.

    1969-01-01

    Technical report is presented on sodium and lithium cells using fused salt electrolytes. It includes a discussion of the thermally regenerative galvanic cell and the secondary bimetallic cell for storage of electricity.

  4. Practical azidation of 1,3-dicarbonyls.

    PubMed

    Harschneck, Tobias; Hummel, Sara; Kirsch, Stefan F; Klahn, Philipp

    2012-01-23

    An operationally simple, direct azidation of 1,3-dicarbonyl compounds has been developed. The reaction proceeds readily under ambient conditions using sodium azide and an iodine-based oxidant such as I(2) or 2-iodoxybenzoic acid (IBX)-SO(3)K/NaI. In particular, the latter method, as a new and well-balanced oxidizing agent, shows excellent functional group tolerance and substrate scope and thus allows access to a variety of tertiary 2-azido and 2,2-bisazido 1,3-dicarbonyl compounds that would be more difficult to access by using traditional methods. Because the azide-containing products easily undergo 1,3-dipolar cycloaddition with alkynes, our report represents a novel route to analogues of sensitive complex molecules.

  5. Finite Element Method Applied to Fuse Protection Design

    NASA Astrophysics Data System (ADS)

    Li, Sen; Song, Zhiquan; Zhang, Ming; Xu, Liuwei; Li, Jinchao; Fu, Peng; Wang, Min; Dong, Lin

    2014-03-01

    In a poloidal field (PF) converter module, fuse protection is of great importance to ensure the safety of the thyristors. The fuse is pre-selected in a traditional way and then verified by finite element analysis. A 3D physical model is built by ANSYS software to solve the thermal-electric coupled problem of transient process in case of external fault. The result shows that this method is feasible.

  6. Carcinogenicity of 1,3-butadiene.

    PubMed Central

    Melnick, R L; Shackelford, C C; Huff, J

    1993-01-01

    1,3-Butadiene, a high-production volume chemical used largely in the manufacture of synthetic rubber, is a multiple organ carcinogen in rats and mice. In inhalation studies conducted in mice by the National Toxicology Program, high rates of early lethal lymphomas occurring at exposure levels of 625 ppm or higher reduced the development and expression of later developing tumors at other sites. Use of survival-adjusted tumor rates to account for competing risk factors provided a clearer indication of the dose responses for 1,3-butadiene-induced neoplasms. An increase in lung tumors in female mice was observed at exposure concentrations as low as 6.25 ppm, the lowest concentration ever used in a long-term carcinogenicity study of this gas. Human exposures to 1,3-butadiene by workers employed at facilities that produce this chemical and at facilities that produce styrene-butadiene rubber have been measured at levels higher than those that cause cancer in animals. Furthermore, epidemiology studies have consistently revealed associations between occupational exposure to 1,3-butadiene and excess mortality due to lymphatic and hematopoietic cancers. In response to the carcinogenicity findings for 1,3-butadiene in animals and in humans, the Occupational Safety and Health Administration has proposed lowering the occupational exposure standard for this chemical from 1000 ppm to 2 ppm. Future work is needed to understand the mechanisms of tumor induction by 1,3-butadiene; however, the pursuit of this research should not delay the reduction of human exposure to this chemical. PMID:8354171

  7. Screening of perfluorinated compounds in water, sediment and biota of the Llobregat River basin (NE Spain)

    NASA Astrophysics Data System (ADS)

    Campo, Julian; Perez, Francisca; Pico, Yolanda; Farre, Marinella; Barcelo, Damia; Andreu, Vicente

    2014-05-01

    PFCs present significant thermal and chemical stability being persistent in the environment, where they can bio-accumulate and adversely affect humans and wildlife (Llorca et al., 2012). Human exposure to PFCs is of concern since PFCs tend to be associated with fatty acid binding proteins in the liver or albumin proteins in blood, and have been detected in human serum, urine, saliva, seminal plasma and breast milk (Sundstrom et al., 2011). This study is aimed at the screening of 21 perfluorinated compounds (PFCs) in environmental samples by high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS). The main objective is to identify target compounds at low levels in water, sediments and biota of the Llobregat River (2010), second longest river in Catalonia and one of Barcelona's major drinking water resources. PFCs were extracted from water samples by Solid Phase Extraction (SPE); from sediment by ultrasonication with acidified methanol followed by an off-line SPE procedure (Picó et al., 2012), and from biota (fish) with alkaline digestion, clean-up by TurboFlow™ on line technology coupled to LC-MS/MS (Llorca et al., 2012). The limits of detection (LODs) and limits of quantification (LOQs) of the method were calculated by analysis of spiked river water, sediment, and biota with minimum concentrations of each individual compound at a signal-to-noise ratio of 3 and 10, respectively. The LODs and LOQs of the method in river water ranged between 0.004 and 0.8 ng L-1 and between 0.01 and 2 ng L-1, respectively. In sediment LODs were 0.013-2.667 ng g-1 dry weight (dw) and LOQs were 0.04-8 ng g-1 dw, meanwhile in biota these were 0.006-0.7 pg μL-1 and 0.02-2.26 pg μL-1, respectively. Recoveries ranged between 65% and 102% for all target compounds. The method was applied to study the spatial distribution of these compounds in the Llobregat River basin. For this, a total of 40 samples were analysed (14 water, 14 sediments, 12 fishes). Of the 21 target

  8. 45 CFR 1211.1-3 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... VOLUNTEER GRIEVANCE PROCEDURES § 1211.1-3 Definitions. (a) Volunteer means a person enrolled and currently serving as a full-time volunteer under part A of title I of the Domestic Volunteer Service Act of 1973. For the purpose of this part, a volunteer whose service has terminated shall be deemed to be...

  9. 45 CFR 1211.1-3 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... VOLUNTEER GRIEVANCE PROCEDURES § 1211.1-3 Definitions. (a) Volunteer means a person enrolled and currently serving as a full-time volunteer under part A of title I of the Domestic Volunteer Service Act of 1973. For the purpose of this part, a volunteer whose service has terminated shall be deemed to be...

  10. 45 CFR 1211.1-3 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... conditions of service resulting in the denial or infringement of a right or benefit to the grieving volunteer... VOLUNTEER GRIEVANCE PROCEDURES § 1211.1-3 Definitions. (a) Volunteer means a person enrolled and currently serving as a full-time volunteer under part A of title I of the Domestic Volunteer Service Act of...

  11. 45 CFR 1211.1-3 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... conditions of service resulting in the denial or infringement of a right or benefit to the grieving volunteer... VOLUNTEER GRIEVANCE PROCEDURES § 1211.1-3 Definitions. (a) Volunteer means a person enrolled and currently serving as a full-time volunteer under part A of title I of the Domestic Volunteer Service Act of...

  12. 45 CFR 1211.1-3 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... conditions of service resulting in the denial or infringement of a right or benefit to the grieving volunteer... VOLUNTEER GRIEVANCE PROCEDURES § 1211.1-3 Definitions. (a) Volunteer means a person enrolled and currently serving as a full-time volunteer under part A of title I of the Domestic Volunteer Service Act of...

  13. A Dogrib History. Grade 1-3.

    ERIC Educational Resources Information Center

    Fraser, Tara

    A publication on the history and traditional lifestyle of the Dogrib Tribe of Canada's Northwest Territories is intended for use in grades 1-3. Text is printed in large, clear letters and accompanied by many drawings. Some subjects covered are cooking, food, canoes, clothes, homes, and games. Sections are devoted to beavers and caribou and their…

  14. 45 CFR 1210.1-3 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... VISTA TRAINEE DESELECTION AND VOLUNTEER EARLY TERMINATION PROCEDURES General § 1210.1-3 Definitions. (a... of supporting VISTA Volunteers on a national or multi-regional basis. VISTA Volunteers may be... affiliate of a national grantee to which VISTA Volunteers are assigned under the VISTA National...

  15. Natural 1,3-Dipolar Cycloadditions.

    PubMed

    Baunach, Martin; Hertweck, Christian

    2015-10-19

    [3+2] in the wild: Biomimetic natural product syntheses and theoretical considerations have indicated that 1,3-dipolar cycloadditions take place in nature. Now, the structure, biosynthesis, and function of a heavily modified prenylated flavin cofactor have been elucidated. In the azomethine ylide form, it undergoes [3+2] cycloadditions with aromatic acids and promotes their decarboxylation. PMID:26465651

  16. Simultaneous determination of perfluorinated compounds and their potential precursors in mussel tissue and fish muscle tissue and liver samples by liquid chromatography-electrospray-tandem mass spectrometry.

    PubMed

    Zabaleta, I; Bizkarguenaga, E; Prieto, A; Ortiz-Zarragoitia, M; Fernández, L A; Zuloaga, O

    2015-03-27

    An analytical method for the simultaneous determination in fish liver and muscle tissue and mussel samples of 14 perfluorinated compounds (PFCs), including three perfluoroalkylsulfonates (PFSAs), seven perfluorocarboxylic acids (PFCAs), three perfluorophosphonic acids (PFPAs) and perfluorooctanesulfonamide (PFOSA), and 10 potential precursors, including four polyfluoroalkyl phosphates (PAPs), four fluorotelomer saturated acids (FTCAs) and two fluorotelomer unsaturated acids (FTUCAs), was developed in the present work. Different clean-up strategies by means of solid-phase extraction (SPE) using a mix-mode weak anion exchanger (WAX), reverse phase Envi-Carb or a combination of them was optimized and evaluated for the clean-up of focused ultrasonic solid-liquid (FUSLE) extracts before the analysis by liquid chromatography-triple quadrupole tandem mass spectrometry (LC-MS/MS). Mix-mode WAX coupled in-line to Envi-Carb was finally selected since it rendered the cleanest extracts and minimum matrix effect. The FUSLE-SPE-LC-MS/MS methodology was validated in terms of recovery, precision and method detection limits (MDLs). Apparent recovery values in the 65-116%, 59-119% and 67-126% range and MDLs in the 0.1-2.7 ng/g, 0.1-3.8 ng/g and 0.2-3.1ng/g range were obtained for liver, mussel and fish muscle tissue samples, respectively. The method developed was applied to the analysis of grey mullet liver (Chelon labrosus) and mussel (Mytilus galloprovincialis) samples from the Basque Coast (North of Spain) and Yellowfin tuna muscle tissue (Thunnus albacares) samples from the Indian Ocean. To the best of our knowledge this is the first method that describes the simultaneous determination of 14 PFCs and 10 potential precursors in fish liver, fish muscle tissue and mussel samples. Besides, this is the first time that 8:2 monosubstituted polyfluorodecyl phosphate (8:2 monoPAP) and 8:2 disubstituted polyfluorodecyl phosphate (8:2 diPAP) were detected in mussel and tuna samples

  17. Process for manufacturing hollow fused-silica insulator cylinder

    DOEpatents

    Sampayan, Stephen E.; Krogh, Michael L.; Davis, Steven C.; Decker, Derek E.; Rosenblum, Ben Z.; Sanders, David M.; Elizondo-Decanini, Juan M.

    2001-01-01

    A method for building hollow insulator cylinders that can have each end closed off with a high voltage electrode to contain a vacuum. A series of fused-silica round flat plates are fabricated with a large central hole and equal inside and outside diameters. The thickness of each is related to the electron orbit diameter of electrons that escape the material surface, loop, and return back. Electrons in such electron orbits can support avalanche mechanisms that result in surface flashover. For example, the thickness of each of the fused-silica round flat plates is about 0.5 millimeter. In general, the thinner the better. Metal, such as gold, is deposited onto each top and bottom surface of the fused-silica round flat plates using chemical vapor deposition (CVD). Eutectic metals can also be used with one alloy constituent on the top and the other on the bottom. The CVD, or a separate diffusion step, can be used to defuse the deposited metal deep into each fused-silica round flat plate. The conductive layer may also be applied by ion implantation or gas diffusion into the surface. The resulting structure may then be fused together into an insulator stack. The coated plates are aligned and then stacked, head-to-toe. Such stack is heated and pressed together enough to cause the metal interfaces to fuse, e.g., by welding, brazing or eutectic bonding. Such fusing is preferably complete enough to maintain a vacuum within the inner core of the assembled structure. A hollow cylinder structure results that can be used as a core liner in a dielectric wall accelerator and as a vacuum envelope for a vacuum tube device where the voltage gradients exceed 150 kV/cm.

  18. Spectral and spatial characterization of perfluorinated graded-index polymer optical fibers for the distribution of optical wireless communication cells.

    PubMed

    Hajjar, Hani Al; Montero, David S; Lallana, Pedro C; Vázquez, Carmen; Fracasso, Bruno

    2015-02-10

    In this paper, the characterization of a perfluorinated graded-index polymer optical fiber (PF-GIPOF) for a high-bitrate indoor optical wireless system is reported. PF-GIPOF is used here to interconnect different optical wireless access points that distribute optical free-space high-bitrate wireless communication cells. The PF-GIPOF channel is first studied in terms of transmission attenuation and frequency response and, in a second step, the spatial power profile distribution at the fiber output is analyzed. Both characterizations are performed under varying restricted mode launch conditions, enabling us to assess the transmission channel performance subject to potential connectorization errors within an environment where the end users may intervene by themselves on the home network infrastructure.

  19. Perfluorinated compounds and polybrominated diphenyl ethers in great blue heron eggs from Indiana Dunes National Lakeshore, Indiana

    USGS Publications Warehouse

    Custer, T.W.; Kannan, K.; Tao, L.; Saxena, A.R.; Route, B.

    2009-01-01

    In 2007 archived great blue heron (Ardea herodias) eggs collected from Indiana Dunes National Lakeshore, IN, (Indiana Dunes) in 1993 were analyzed for 11 perfluorinated compounds (PFCs) and 7 polybrominated diphenyl ethers (PBDEs). Concentrations of perfluorooctane sulfonate, the major contributor to total PFC concentrations, were below the toxicity thresholds estimated for bobwhite quail (Colinus virginianus) and mallards (Anas platyrhynchos), but within the toxicity threshold estimated for white leghorn chickens (Gallus domesticus). The ranking of PBDE congener concentrations by percent concentration (PBDE-47 > -99 > -100 > -153 > -154 > -28 > -183) was consistent with the Penta-PBDE formulation. Total PBDE concentrations in great blue heron eggs from Indiana Dunes were elevated and probably reflect local contamination from highly urbanized and industrialized inputs into Lake Michigan. Polybrominated diphenyl ether concentrations were within levels associated with altered reproductive behavior in other avian species and based on trends in other Great Lakes birds are probably higher today.

  20. FAST TRACK COMMUNICATION: Enhanced dc conductivity of low volume-fraction nano-particulate suspensions in silicone and perfluorinated oils

    NASA Astrophysics Data System (ADS)

    Wilson, S. A.; Libor, Z.; Skordos, A. A.; Zhang, Q.

    2009-03-01

    The dc conductivities of several different types of nanoparticles (nickel, barium titanate and magnetite) suspended in both silicone and perfluorinated oils have been measured and contrasted. Enhanced dc conductivity through interaction between the particles and the fluid has been demonstrated, even at quite moderate fields, and different types of nanoparticles have been shown to exhibit different behavioural trends. Whilst the dc enhancement is partly related to the concentration (or spatial arrangement) of the particles as expected, there is clear evidence that energy-activated (electric field activated) processes also play a major role. It can be said that effective-medium theories based solely on the electrical properties and volume fractions of the component materials have limited applicability when assessing the dc conductivities of these nanoparticle-fluid combinations at low volume fractions.

  1. Per-fluorinated sulfonic acid/PTFE copolymer studied by positron annihilation lifetime and gas permeation techniques

    NASA Astrophysics Data System (ADS)

    Mohamed, Hamdy F. M.; Abdel-Hady, E. E.; Ohira, A.

    2015-06-01

    The mechanism of gas permeation in per-fluorinated sulfonic acid/PTFE copolymer Fumapem® membranes for polymer electrolyte fuel cells has been investigated from the viewpoint of free volume. Three different samples, Fumapem® F-950, F-1050 and F-14100 membranes with ion exchange capacity (IEC) = 1.05, 0.95 and 0.71 meq/g, respectively were used after drying. Free volume was quantified using the positron annihilation lifetime (PAL) technique and gas permeabilities were measured for O2 and H2 as function of temperature. Good linear correlation between the logarithm of the permeabilities at different temperatures and reciprocal free volume indicate that gas permeation in dry Fumapem® is governed by the free volume. Nevertheless permeabilities are much smaller than the corresponding flexible chain polymer with a similar free volume size due to stiff chains of the perfluoroethylene backbone.

  2. Optical coatings of variable refractive index and high laser-resistance from physical-vapor-deposited perfluorinated amorphous polymer

    DOEpatents

    Chow, Robert; Loomis, Gary E.; Thomas, Ian M.

    1999-01-01

    Variable index optical single-layers, optical multilayer, and laser-resistant coatings were made from a perfluorinated amorphous polymer material by physical vapor deposition. This was accomplished by physically vapor depositing a polymer material, such as bulk Teflon AF2400, for example, to form thin layers that have a very low refractive index (.about.1.10-1.31) and are highly transparent from the ultra-violet through the near infrared regime, and maintain the low refractive index of the bulk material. The refractive index can be varied by simply varying one process parameter, either the deposition rate or the substrate temperature. The thus forming coatings may be utilized in anti-reflectors and graded anti-reflection coatings, as well as in optical layers for laser-resistant coatings at optical wavelengths of less than about 2000 nm.

  3. Optical coatings of variable refractive index and high laser-resistance from physical-vapor-deposited perfluorinated amorphous polymer

    DOEpatents

    Chow, R.; Loomis, G.E.; Thomas, I.M.

    1999-03-16

    Variable index optical single-layers, optical multilayer, and laser-resistant coatings were made from a perfluorinated amorphous polymer material by physical vapor deposition. This was accomplished by physically vapor depositing a polymer material, such as bulk Teflon AF2400, for example, to form thin layers that have a very low refractive index (ca. 1.10--1.31) and are highly transparent from the ultra-violet through the near infrared regime, and maintain the low refractive index of the bulk material. The refractive index can be varied by simply varying one process parameter, either the deposition rate or the substrate temperature. The thus forming coatings may be utilized in anti-reflectors and graded anti-reflection coatings, as well as in optical layers for laser-resistant coatings at optical wavelengths of less than about 2000 nm. 2 figs.

  4. Fate of a broad spectrum of perfluorinated compounds in soils and biota from Tierra del Fuego and Antarctica.

    PubMed

    Llorca, Marta; Farré, Marinella; Tavano, Máximo Sebastián; Alonso, Bruno; Koremblit, Gabriel; Barceló, Damià

    2012-04-01

    In this study, the presence of 18 perfluorinated compounds was investigated in biota and environmental samples from the Antarctica and Tierra de Fuego, which were collected during a sampling campaign carried out along February and March 2010. 61 samples were analysed including fish, superficial soils, guano, algae, dung and tissues of Papua penguin by liquid chromatography coupled to tandem mass spectrometry. The concentrations of PFCs were ranging from 0.10 to 240 ng/g for most of the samples except for penguin dung, which presented levels between 95 and 603 ng/g for perfluorooctane sulfonate, and guano samples from Ushuaia, with concentration levels of 1190-2480 ng/g of perfluorohexanoic acid. PFCs acids presented, in general, the highest levels of concentration and perfluorooctanesulfonate was the most frequently found compound. The present study provides a significant amount of results, which globally supports the previous studies, related to the transport, deposition, biodegradation and bioaccumulation patterns of PFCs.

  5. 30 CFR 56.12037 - Fuses in high-potential circuits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fuses in high-potential circuits. 56.12037 Section 56.12037 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... § 56.12037 Fuses in high-potential circuits. Fuse tongs or hot line tools shall be used when fuses...

  6. 30 CFR 57.12037 - Fuses in high-potential circuits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fuses in high-potential circuits. 57.12037... Electricity Surface and Underground § 57.12037 Fuses in high-potential circuits. Fuse tongs or hotline tools, shall be used when fuses are removed or replaced in high-potential circuits....

  7. 30 CFR 28.3 - Installation, use, and maintenance of approved fuses.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... fuses. 28.3 Section 28.3 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS FUSES FOR USE WITH DIRECT CURRENT IN PROVIDING SHORT... maintenance of approved fuses. Approved fuses shall be installed and maintained in accordance with...

  8. 30 CFR 57.12037 - Fuses in high-potential circuits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Fuses in high-potential circuits. 57.12037... Electricity Surface and Underground § 57.12037 Fuses in high-potential circuits. Fuse tongs or hotline tools, shall be used when fuses are removed or replaced in high-potential circuits....

  9. 30 CFR 57.12037 - Fuses in high-potential circuits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Fuses in high-potential circuits. 57.12037... Electricity Surface and Underground § 57.12037 Fuses in high-potential circuits. Fuse tongs or hotline tools, shall be used when fuses are removed or replaced in high-potential circuits....

  10. 30 CFR 57.12037 - Fuses in high-potential circuits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Fuses in high-potential circuits. 57.12037... Electricity Surface and Underground § 57.12037 Fuses in high-potential circuits. Fuse tongs or hotline tools, shall be used when fuses are removed or replaced in high-potential circuits....

  11. Bilateral maxillary fused second and third molars: a rare occurrence

    PubMed Central

    Liang, Rui-Zhen; Wu, Jin-Tao; Wu, You-Nong; Smales, Roger J; Hu, Ming; Yu, Jin-Hua; Zhang, Guang-Dong

    2012-01-01

    This case report describes the diagnosis and endodontic therapy of maxillary fused second and third molars, using cone-beam computed tomography (CBCT). A 31-year-old Chinese male, with no contributory medical or family/social history, presented with throbbing pain in the maxillary right molar area following an unsuccessful attempted tooth extraction. Clinical examination revealed what appeared initially to be a damaged large extra cusp on the buccal aspect of the distobuccal cusp of the second molar. However, CBCT revealed that a third molar was fused to the second molar. Unexpectedly, the maxillary left third molar also was fused to the second molar, and the crown of an unerupted supernumerary fourth molar was possibly also fused to the apical root region of the second molar. Operative procedures should not be attempted without adequate radiographic investigation. CBCT allowed the precise location of the root canals of the right maxillary fused molar teeth to permit successful endodontic therapy, confirmed after 6 months. PMID:23222992

  12. Quantification of Residual Stress from Photonic Signatures of Fused Silica

    NASA Technical Reports Server (NTRS)

    Cramer, K. Elliott; Hayward, Maurice; Yost, William E.

    2013-01-01

    A commercially available grey-field polariscope (GFP) instrument for photoelastic examination is used to assess impact damage inflicted upon the outer-most pane of Space Shuttle windows made from fused silica. A method and apparatus for calibration of the stress-optic coefficient using four-point bending is discussed. The results are validated on known material (acrylic) and are found to agree with literature values to within 6%. The calibration procedure is then applied to fused-silica specimens and the stress-optic coefficient is determined to be 2.43 +/- 0.54 x 10(exp -12)/Pa. Fused silica specimens containing impacts artificially made at NASA's Hypervelocity Impact Technology Facility (HIT-F), to simulate damage typical during space flight, are examined. The damage sites are cored from fused silica window carcasses and examined with the GFP. The calibrated GFP measurements of residual stress patterns surrounding the damage sites are presented. Keywords: Glass, fused silica, photoelasticity, residual stress

  13. Ceramic on ceramic hip arthroplasty in fused hips

    PubMed Central

    Park, Kyung-Soon; Yoon, Taek-Rim; Lee, Tae-Min; Ahn, Yeong-Seub

    2015-01-01

    Background: Most literature in the field of total hip arthroplasty (THA) for fused hips, until date has reported the results of using metal on polyethylene and ceramic on polyethylene bearings. Results of THA using ceramic on ceramic (CoC) bearings in fused hips have not been published in literature. This study reports the results of cementless THA using CoC articulation perfomed in fused hips. Materials and Methods: Twenty-three patients (25 hips) with fused hips underwent conversion to THA using CoC bearings and were followed up for a mean 5.4 years. The conventional posterolateral approach was used in 15 hips, a modified two incision technique in 7 hips and a direct lateral approach with greater trochanteric osteotomy in 3 hips. Postoperatively, range of motion exercises were encouraged after 2–3 days of bed rest and subsequent gradual weight bearing using crutches was begun. Results: Mean Harris hip score improved from 42.4 to 84.2 and mean leg lengthening of 36.6 mm was achieved. In the average 5.4 years (range 2.8-9.1 years) followup there were no cases with osteolysis around acetabular cup and femoral stem. In this study, there was no case of ceramic fracture. There was one case of squeaking. Conclusion: This study suggests that cementless THA performed for fused hips with CoC bearings can provide good early clinical results. PMID:26015635

  14. Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)

    Integrated Risk Information System (IRIS)

    Hexahydro - 1,3,5 - trinitro - 1,3,5 - triazine ( RDX ) ; CASRN 121 - 82 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health

  15. Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)

    Integrated Risk Information System (IRIS)

    Octahydro - 1,3,5,7 - tetranitro - 1,3,5,7 - tetr . . . ( HMX ) ; CASRN 2691 - 41 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I

  16. HVI Ballistic Limit Characterization of Fused Silica Thermal Panes

    NASA Technical Reports Server (NTRS)

    Miller, J. E.; Bohl, W. D.; Christiansen, E. L.; Davis, B. A.; Deighton, K. D.

    2015-01-01

    Fused silica window systems are used heavily on crewed reentry vehicles, and they are currently being used on the next generation of US crewed spacecraft, Orion. These systems improve crew situational awareness and comfort, as well as, insulating the reentry critical components of a spacecraft against the intense thermal environments of atmospheric reentry. Additionally, these materials are highly exposed to space environment hazards like solid particle impacts. This paper discusses impact studies up to 10 km/s on a fused silica window system proposed for the Orion spacecraft. A ballistic limit equation that describes the threshold of perforation of a fuse silica pane over a broad range of impact velocities, obliquities and projectile materials is discussed here.

  17. Microwave attenuation of multiwalled carbon nanotube-fused silica composites

    SciTech Connect

    Xiang Changshu; Pan Yubai; Liu Xuejian; Sun Xingwei; Shi Xiaomei; Guo Jingkun

    2005-09-19

    Multiwalled carbon nanotubes (MWCNTs) were used to convert radome materials to microwave absorbing materials. Dense MWCNT-fused silica composites were prepared by hot-pressing technique. The composites exhibit high complex permittivities at X-band frequencies, depending on the content of MWCNTs. The value of the loss tangent increases three orders over pure fused silica only by incorporating 2.5 vol % MWCNTs into the composites. The average magnitude of microwave transmission reaches -33 dB at 11-12 GHz in the 10 vol % MWCNT-fused silica composites, which indicates the composites have excellent microwave attenuation properties. The attenuation properties mainly originate from the electric loss of MWCNTs by the motion of conducting electrons.

  18. Interdisciplinary Treatment of a Fused Lower Premolar with Supernumerary Tooth

    PubMed Central

    Gadimli, Cengiz; Sari, Zafer

    2011-01-01

    The objective of this report is to describe combined orthodontic and endodontic treatment of a fused mandibular premolar with supernumerary tooth. The patient was a 15 year old girl seeking orthodontic treatment for the correction of maxillary and mandibular crowding. Cephalometric examination revealed skeletally Class I relationship. The panoramic radiograph showed a fused tooth with two separate pulp chambers and two separate root canals connecting in apical third. After the endodontic treatment of the fused teeth, the stripping of the supernumerary tooth was performed to establish a Class I canine relationship and to correct midline deviation. At the end of the treatment, the crowding was resolved and positive overjet and overbite was achieved. PMID:21769280

  19. Micromachined contact fuses for earth penetrator applications. LDRD final report

    SciTech Connect

    Davies, B.R.; Montague, S.; Smith, J.H.; Rimkus, V.C.

    1998-01-01

    MEMS is an enabling technology that may provide low-cost devices capable of sensing motion in a reliable and accurate manner. This paper describes preliminary work in MEMS contact fuse development at Sandia National Laboratories. This work leverages a process for integrating both the micromechanical structures and microelectronics circuitry of a MEMS devices on the same chip. The design and test results of an integrated MEMS high-g accelerometer will be detailed. This design could be readily modified to create a high-g switching device suitable for a contact fuse. A potential design for a low-g acceleration measurement device (suitable for such fusing operations as path length measurement device of both whole path length or safe separation distance) for artillery rounds and earth penetrator devices will also be discussed in this document (where 1 g {approx} 9.81 m/s{sup 2}).

  20. Biodegradation of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine

    PubMed Central

    McCormick, N. G.; Cornell, J. H.; Kaplan, A. M.

    1981-01-01

    Biodegradation of the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) occurs under anaerobic conditions, yielding a number of products, including: hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine, hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine, hexahydro-1,3,5-trinitroso-1,3,5-triazine, hydrazine, 1,1-dimethyl-hydrazine, 1,2-dimethylhydrazine, formaldehyde, and methanol. A scheme for the biodegradation of RDX is proposed which proceeds via successive reduction of the nitro groups to a point where destabilization and fragmentation of the ring occurs. The noncyclic degradation products arise via subsequent reduction and rearrangement reactions of the fragments. The scheme suggests the presence of several additional compounds, not yet identified. Several of the products are mutagenic or carcinogenic or both. Anaerobic treatment of RDX wastewaters, which also contain high nitrate levels, would permit the denitrification to occur, with concurrent degradation of RDX ultimately to a mixture of hydrazines and methanol. The feasibility of using an aerobic mode in the further degradation of these products is discussed. PMID:16345884

  1. Aromaticity Competition in Differentially Fused Borepin-Containing Polycyclic Aromatics.

    PubMed

    Messersmith, Reid E; Siegler, Maxime A; Tovar, John D

    2016-07-01

    This report describes the synthesis and characterization of a series of borepin-based polycyclic aromatics bearing two different arene fusions. The borepin synthesis features streamlined Ti-mediated alkyne reduction, leading to Z-olefins, followed by direct lithiation and borepin formation. These molecules allow for an assessment of aromatic competition between the fused rings and the central borepin core. Crystallographic, magnetic, and computational studies yielded insights about the aromaticity of novel, differentially fused [b,f]borepins and allowed for comparison to literature compounds. Multiple borepin motifs were also incorporated into polycyclic aromatics with five or six rings in the main backbone, and their properties were also evaluated.

  2. FUSE Observations of Galactic and LMC Novae in Outburst

    NASA Technical Reports Server (NTRS)

    Huschildt, P. H.

    2001-01-01

    This document is a collection of five abstracts from papers written on the 'FUSE Observations of Galactic and LMC Novae in Outburst'. The titles are the following: (1) Analyzing FUSE Observations of Galactic and LMC Novae; (2) Detailed NLTE Model Atmospheres for Novae during Outburst: Modeling Optical and Ultraviolet Observations for Nova LMC 1988; (3) Numerical Solution of the Expanding Stellar Atmosphere Problem; (4) A Non-LTE Line-Blanketed Expanding Atmosphere Model for A-supergiant Alpha Cygni; and (5) Non-LTE Model Atmosphere Analysis of the Early Ultraviolet Spectra of Nova Andromedae 1986. A list of journal publications is also included.

  3. Coated Fused Silica Fibers for Enhanced Sensitivity Torsion Pendulum

    NASA Technical Reports Server (NTRS)

    Numata, Kenji; Horowitz, Jordan; Camp, Jordan

    2007-01-01

    In order to investigate the fundamental thermal noise limit of a torsion pendulum using a fused silica fiber, we systematically measured and modeled the mechanical losses of thin fused silica fibers coated by electrically conductive thin metal films. Our results indicate that it is possible to achieve a thermal noise limit for coated silica lower by a factor between 3 and 9, depending on the silica diameter, compared to the best tungsten fibers available. This will allow a corresponding increase in sensitivity of torsion pendula used for weak force measurements, including the gravitational constant measurement and ground-based force noise testing for the Laser Interferometer Space Antenna (LISA) mission.

  4. Bonding energy of Sylgard on fused quartz: an experimental investigation

    NASA Astrophysics Data System (ADS)

    Liu, C.; Yeager, J. D.; Ramos, K. J.

    2015-02-01

    The bonding energy between the polymer Sylgard and fused quartz is determined experimentally using a miniature bulge test combined with three-dimensional digital image correlation (3D-DIC). Based on the experimental observation, Mindlin plate theory is used to compute the bonding energy (adhesive energy or surface energy) between the Sylgard and the fused quartz. The experimental results demonstrate that the combination of the miniature bulge test and the 3D-DIC provides a viable tool to directly measure interfacial and bonding properties.

  5. Bioaccumulation of perfluorinated carboxylates and sulfonates and polychlorinated biphenyls in laboratory-cultured Hexagenia spp., Lumbriculus variegatus and Pimephales promelas from field-collected sediments.

    PubMed

    Prosser, R S; Mahon, K; Sibley, P K; Poirier, D; Watson-Leung, T

    2016-02-01

    Polychlorinated biphenyls (PCBs) and perfluorinated carboxylates and sulfonates (PFASs) are persistent pollutants in sediment that can potentially bioaccumulate in aquatic organisms. The current study investigates variation in the accumulation of PCBs and PFASs in laboratory-cultured Hexagenia spp., Lumbriculus variegatus and Pimephales promelas from contaminated field-collected sediment using 28-day tests. BSAF(lipid) (lipid-normalized biota-sediment accumulation factor) values for total concentration of PCBs were greater in Hexagenia spp. relative to L. variegatus and P. promelas. The distribution of congeners contributing to the total concentration of PCBs in tissue varied among the three species. Trichlorobiphenyl congeners composed the greatest proportion of the total concentration of PCBs in L. variegatus while tetra- and pentabiphenyl congeners dominated in Hexagenia spp. and P. promelas. Perfluorooctane sulfonate (PFOS) was present in all three species at concentrations greater than all other PFASs analyzed. Hexagenia spp. also produced the greatest BSAF(lipid) and BSAF(ww) (non-lipid-normalized biota-sediment accumulation factor) values for PFOS relative to the other two species. However, this was not the case for all PFASs. The trend of BSAF values and number of carbon atoms in the perfluoroalkyl chain of perfluorinated carboxylates varied among the three species but was similar for perfluorinated sulfonates. Differences in the dominant pathways of exposure (e.g., water, sediment ingestion) likely explain a large proportion of the variation in accumulation observed across the three species. PMID:26615489

  6. Silyl- and disilanyl-1,3-butadiyne polymers from hexachloro-1,3-butadiene

    DOEpatents

    Barton, Thomas J.; Ijadi-Maghsoodi, Sina

    1990-10-23

    Organosilane polymers having recurring silylene-1,3-butadiyne and/or disilylene-1,3-butadiyne units are prepared in a one-pot synthesis from hexachlorobutadiene. Depending on the organic substituents (R and R'), these polymers have useful film-forming properties, and are converted to the ceramic, silicon carbide upon heating a very uniform high char yields. They can also be pulled into fibers. The polymers are thermally crosslinked above 100.degree. C.

  7. Silyl- and disilanyl-1,3-butadiyne polymers from hexachloro-1,3-butadiene

    DOEpatents

    Barton, T.J.; Ijadi-Maghsoodi, S.

    1990-10-23

    Organosilane polymers having recurring silylene-1,3-butadiyne and/or disilylene-1,3-butadiyne units are prepared in a one-pot synthesis from hexachlorobutadiene. Depending on the organic substituents (R and R[prime]), these polymers have useful film-forming properties, and are converted to the ceramic, silicon carbide upon heating a very uniform high char yields. They can also be pulled into fibers. The polymers are thermally crosslinked above 100 C.

  8. On the non-planarity of 1,3-dioxole and 1,3-dioxolane

    NASA Astrophysics Data System (ADS)

    Vila, Antonio; Mosquera, Ricardo A.

    2010-03-01

    The conformational preferences of 1,3-dioxole and 1,3-dioxolane are explained on the basis of the QTAIM electron density analysis of B3LYP/6-311++G(2d,2p) electron distributions, supporting the interpretation of the anomeric effect previously proposed by Vila and Mosquera [14]. Thus, distances from methylenic hydrogens to oxygen lone pairs and H-C-O- lp dihedral angles sufficiently explain the atomic population and energy variations, thereby explaining the ring puckering preference.

  9. The T1 domain of Kv1.3 mediates intracellular targeting to axons.

    PubMed

    Rivera, Jacqueline F; Chu, Po-Ju; Arnold, Don B

    2005-10-01

    Shaker K+ channels play an important role in modulating electrical excitability of axons. Recent work has demonstrated that the T1 tetramerization domain of Kv1.2 is both necessary and sufficient for targeting of the channel to the axonal surface [Gu, C., Jan, Y.N. & Jan, L.Y. (2003) Science,301, 646-649]. Here we use a related channel, Kv1.3, as a model to investigate cellular mechanisms that mediate axonal targeting. We show that the T1 domain of Kv1.3 is necessary and sufficient to mediate targeting of the channel to the axonal surface in pyramidal neurons in slices of cortex from neonatal rat. The T1 domain is also sufficient to cause preferential axonal localization of intracellular protein, which indicates that the domain probably does not work through compartment-specific endocytosis or compartment-specific vesicle docking. To determine whether the T1 domain mediates axonal trafficking of transport vesicles, we compared the trafficking of vesicles containing green fluorescent protein-labelled transferrin receptor with those containing the same protein fused with the T1 domain in living cortical neurons. Vesicles containing the wild-type transferrin receptor did not traffic to the axon, in accord with previously published results; however, those containing the transferrin receptor fused to T1 did traffic to the axon. These results are consistent with the T1 domain of Kv1.3 mediating axonal targeting by causing transport vesicles to traffic to axons and they represent the first evidence that such a mechanism might underlie axonal targeting. PMID:16262625

  10. 40. Main fuses and knife switch for power to the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    40. Main fuses and knife switch for power to the bridge, located in the control house. This is one of two located at either end of the main electrical panel (photograph 41). Facing east. - Henry Ford Bridge, Spanning Cerritos Channel, Los Angeles-Long Beach Harbor, Los Angeles, Los Angeles County, CA

  11. A Review of Variable Slicing in Fused Deposition Modeling

    NASA Astrophysics Data System (ADS)

    Nadiyapara, Hitesh Hirjibhai; Pande, Sarang

    2016-06-01

    The paper presents a literature survey in the field of fused deposition of plastic wires especially in the field of slicing and deposition using extrusion of thermoplastic wires. Various researchers working in the field of computation of deposition path have used their algorithms for variable slicing. In the study, a flowchart has also been proposed for the slicing and deposition process. The algorithm already been developed by previous researcher will be used to be implemented on the fused deposition modelling machine. To demonstrate the capabilities of the fused deposition modeling machine a case study has been taken. It uses a manipulated G-code to be fed to the fused deposition modeling machine. Two types of slicing strategies, namely uniform slicing and variable slicing have been evaluated. In the uniform slicing, the slice thickness has been used for deposition is varying from 0.1 to 0.4 mm. In the variable slicing, thickness has been varied from 0.1 in the polar region to 0.4 in the equatorial region Time required and the number of slices required to deposit a hemisphere of 20 mm diameter have been compared with that using the variable slicing.

  12. 30 CFR 56.12036 - Fuse removal or replacement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Fuse removal or replacement. 56.12036 Section 56.12036 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES...

  13. 30 CFR 56.12036 - Fuse removal or replacement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Fuse removal or replacement. 56.12036 Section 56.12036 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES...

  14. 30 CFR 56.12036 - Fuse removal or replacement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Fuse removal or replacement. 56.12036 Section 56.12036 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES...

  15. 30 CFR 56.12036 - Fuse removal or replacement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Fuse removal or replacement. 56.12036 Section 56.12036 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES...

  16. Equations of state for fused-hard-sphere fluids

    NASA Astrophysics Data System (ADS)

    Maeso, M. J.; Solana, J. R.

    1993-09-01

    Analytical equations of state for fused-hard-sphere fluids are developed from a generalization of the Carnahan-Starling method for obtaining the equation of state of the hard-sphere fluid. The results are in good agreement with existing simulation data.

  17. Aminopiperidine-Fused Imidazoles as Dipeptidyl Peptidase-IV Inhibitors

    SciTech Connect

    Edmondson, S.; Mastracchio, A; Cox, J; Eiermann, G; He, H; Lyons, K; Patel, R; Patel, S; Petrov, A; et. al.

    2009-01-01

    A new series of DPP-4 inhibitors derived from piperidine-fused benzimidazoles and imidazopyridines is described. Optimization of this class of DPP-4 inhibitors led to the discovery of imidazopyridine 34. The potency, selectivity, cross-species DMPK profiles, and in vivo efficacy of 34 is reported.

  18. Reliable Hydrogel with Mechanical "Fuse Link" in an Aqueous Environment.

    PubMed

    Kondo, Shinji; Hiroi, Takashi; Han, Young-Soo; Kim, Tae-Hwan; Shibayama, Mitsuhiro; Chung, Ung-il; Sakai, Takamasa

    2015-12-01

    A robust hydrogel with a reliable deformation region in an aqueous environment is proposed. The gel has a homogeneous network where hydrophilic/hydrophobic components are uniformly distributed. In an aqueous environment, aggregated hydrophobic segments serve as "mechanical fuse links," inhibiting sudden macroscopic fracture. The gel endures threefold stretching for more than 100 cycles in water without mechanical hysteresis.

  19. Delta FUSE Fairing Installation at Launch Complex 17A

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This NASA Kennedy Space Center (KSC) video release presents footage of the June 19, 1999 installation of the fairing around the Far Ultraviolet Spectroscopic Explorer (FUSE) spacecraft. The spacecraft was previously mated to the Boeing Delta II rocket. Installation took place on Pad A of Launch Complex 17.

  20. Crossed fused renal ectopia: Challenges in diagnosis and management

    PubMed Central

    Solanki, Shailesh; Bhatnagar, Veereshwar; Gupta, Arun K.; Kumar, Rakesh

    2013-01-01

    Aim: Crossed fused renal ectopia is a rare congenital malformation, which is reported to be usually asymptomatic but may have varied presentations. This survey was conducted to study the clinical profile and the challenges posed in the management of this entity. Materials and Methods: Retrospective analysis of 6 patients diagnosed to have crossed fused renal ectopia during 1997-2010. The diagnosis was confirmed during surgical exploration in one patient. In one patient it was detected on antenatal ultrasonography and in the other 4 patients it was detected during investigations for abdominal pain, abdominal mass, anorectal malformation and urinary tract infection. Results: The left moiety was crossed and fused with the right moiety in 4 cases. Ultrasonography was found to be a good screening investigation with useful diagnostic contributions from CT scans, radionuclide scintigraphy and magnetic resonance urography. Micturating cystourethrography revealed presence of VUR in 4 cases, 3 of whom have undergone ureteric reimplantation. Two patients required pyeloplasty for pelviureteric junction obstruction; in one of these patients the upper ureter was entrapped in the isthmus. In one patient, a non-functioning moiety resulted in nephrectomy. All children were asymptomatic at last follow-up with stable renal functions. Conclusions: Crossed fused renal ectopia was detected in most patients during investigation for other problems. It was found more commonly in boys. The left moiety was crossed to the right in the majority of cases. Associated urological problems were found in most cases and required the appropriate surgical management. PMID:23599575

  1. Reliable Hydrogel with Mechanical "Fuse Link" in an Aqueous Environment.

    PubMed

    Kondo, Shinji; Hiroi, Takashi; Han, Young-Soo; Kim, Tae-Hwan; Shibayama, Mitsuhiro; Chung, Ung-il; Sakai, Takamasa

    2015-12-01

    A robust hydrogel with a reliable deformation region in an aqueous environment is proposed. The gel has a homogeneous network where hydrophilic/hydrophobic components are uniformly distributed. In an aqueous environment, aggregated hydrophobic segments serve as "mechanical fuse links," inhibiting sudden macroscopic fracture. The gel endures threefold stretching for more than 100 cycles in water without mechanical hysteresis. PMID:26443000

  2. Quantification of residual stress from photonic signatures of fused silica

    SciTech Connect

    Cramer, K. Elliott; Yost, William T.; Hayward, Maurice

    2014-02-18

    A commercially available grey-field polariscope (GFP) instrument for photoelastic examination is used to assess impact damage inflicted upon the outer-most pane of Space Shuttle windows made from fused silica. A method and apparatus for calibration of the stress-optic coefficient using four-point bending is discussed. The results are validated on known material (acrylic) and are found to agree with literature values to within 6%. The calibration procedure is then applied to fused-silica specimens and the stress-optic coefficient is determined to be 2.43 ± 0.54 × 10{sup −12} Pa{sup −1}. Fused silica specimens containing impacts artificially made at NASA’s Hypervelocity Impact Technology Facility (HIT-F), to simulate damage typical during space flight, are examined. The damage sites are cored from fused silica window carcasses and examined with the GFP. The calibrated GFP measurements of residual stress patterns surrounding the damage sites are presented.

  3. Color contrast enhancement method of infrared polarization fused image

    NASA Astrophysics Data System (ADS)

    Yang, Fan; Xie, Chen

    2015-10-01

    As the traditional color fusion method based on color transfer algorithm has an issue that the color of target and background is similar. A kind of infrared polarization image color fusion method based on color contrast enhancement was proposed. Firstly the infrared radiation intensity image and the polarization image were color fused, and then color transfer technology was used between color reference image and initial fused image in the YCbCr color space. Secondly Otsu segmentation method was used to extract the target area image from infrared polarization image. Lastly the H,S,I component of the color fusion image which obtained by color transfer was adjusted to obtain the final fused image by using target area in the HSI space. Experimental results show that, the fused result which obtained by the proposed method is rich in detail and makes the contrast of target and background more outstanding. And then the ability of target detection and identification can be improved by the method.

  4. D/H Toward Feige 110: First FUSE Results

    NASA Astrophysics Data System (ADS)

    Friedman, S. D.; Howk, J. C.; Andre, M.; Chayer, P.; Moos, H. W.; Oegerle, W. R.; Oliveira, C.; Hebrard, G.; Tripp, T.; FUSE Science Team

    2000-12-01

    We present measurements of neutral deuterium, oxygen, and nitrogen in the local interstellar medium along the sightline toward Feige 110, a subdwarf OB star at a distance of 180 pc in the direction l = 74.09 deg, b = -59.07 deg. The data were obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite, and cover the 910-1185A bandpass at high resolution (< 20 km/sec). The complex spectrum exhibits many stellar features, including broad photospheric Lyman H I, He II and heavy metal absorption . A stellar model has been constructed which accounts for the H I and He II and some metal lines, and serves to improve estimates of the continuum near interstellar absorption lines. We report values of D/O and D/N and, using an H I column density derived from both the FUSE spectra and IUE measurements of the Ly alpha profile, a D/H value. This work is based on data obtained for the FUSE Guaranteed Time Team by the NASA-CNES-CSA FUSE mission operated for NASA by The Johns Hopkins University. Financial support to U. S. participants has been provided by NASA contract NAS5-32985.

  5. The FUSE Survey of Algol-Type Interacting Binary Systems

    NASA Astrophysics Data System (ADS)

    Peters, Geraldine J.; Andersson, B.; Ake, T. B.; Sankrit, R.

    2006-12-01

    A survey of Algol binaries at random phases is currently being carried through with the FUSE spacecraft as part of the FUSE survey and supplemental program. A similar program was undertaken in FUSE Cycle 3. Both programs have produced multiple observations of 12 Algol systems with periods ranging from 1.2 37 d and include direct-impact and disk systems. We report on the status of the program. The absence of O VI absorption in the systems observed to date allows us to place an upper limit on the column density and temperature of the High Temperature Accretion Region, HTAR ( 100,000 K) confirmed in some Algols from earlier IUE data. The HTAR plasma component appears to be distinct from an O VI-emitting polar plasma discovered in FUSE totality observations of RY Per, V356 Sgr, and TT Hya. New observations of the direct-impact system U Cep have provided more information on the geometry and mass flow (including a splash plasma) in the vicinity of a hot spot at phase 0.90 that was discovered earlier. The extent of disk asymmetries in the long period ( 33 d) systems SX Cas and RX Cas is discussed. Models for direct-impact and the disk systems will be presented. The authors appreciate support from NASA grants NAG5-12253, NNG04GL17G, and NAS5-32985.

  6. 59. VIEW OF FUSES AND A CURRENT TRANSFORMER LOCATED IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    59. VIEW OF FUSES AND A CURRENT TRANSFORMER LOCATED IN THE SIGNAL POWER CONDITIONING ROOM. THE CURRENT TRANSFORMER (UPPER RIGHT) IS AN INDUCTION COUPLED SENSOR WHICH IS USED TO REDUCE HIGH CURRENT TO ANALOGOUS LOW VALUES SAFE TO USE IN CONTROL ROOM CIRCUITRY. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

  7. METHOD OF SEPARATING FISSION PRODUCTS FROM FUSED BISMUTH-CONTAINING URANIUM

    DOEpatents

    Wiswall, R.H.

    1958-06-24

    A process is described for removing metal selectively from liquid metal compositions. The method effects separation of flssion product metals selectively from dilute solution in fused bismuth, which contains uraniunn in solution without removal of more than 1% of the uranium. The process comprises contacting the fused bismuth with a fused salt composition consisting of sodium, potassium and lithium chlorides, adding to fused bismuth and molten salt a quantity of bismuth chloride which is stoichiometrically required to convert the flssion product metals to be removed to their chlorides which are more stable in the fused salt than in the molten metal and are, therefore, preferentially taken up in the fused salt phase.

  8. Hysteretic Behavior of Proprotein Convertase 1/3 (PC1/3)

    PubMed Central

    Icimoto, Marcelo Y.; Barros, Nilana M.; Ferreira, Juliana C.; Marcondes, Marcelo F.; Andrade, Douglas; Machado, Mauricio F.; Juliano, Maria A.; Júdice, Wagner A.; Juliano, Luiz; Oliveira, Vitor

    2011-01-01

    The proprotein convertases (PCs) are calcium-dependent proteases responsible for processing precursor proteins into their active forms in eukariotes. The PC1/3 is a pivotal enzyme of this family that participates in the proteolytic maturation of prohormones and neuropeptides inside the regulated secretory pathway. In this paper we demonstrate that mouse proprotein convertase 1/3 (mPC1/3) has a lag phase of activation by substrates that can be interpreted as a hysteretic behavior of the enzyme for their hydrolysis. This is an unprecedented observation in peptidases, but is frequent in regulatory enzymes with physiological relevance. The lag phase of mPC1/3 is dependent on substrate, calcium concentration and pH. This hysteretic behavior may have implications in the physiological processes in which PC1/3 participates and could be considered an additional control step in the peptide hormone maturation processes as for instance in the transformation of proinsulin to insulin. PMID:21935423

  9. Temporal trends of polychlorinated biphenyls, polybrominated diphenyl ethers, and perfluorinated compounds in Chinese sturgeon (Acipenser sinensis) eggs (1984-2008).

    PubMed

    Jianxian, Sun; Hui, Peng; Jianying, Hu

    2015-02-01

    Because investigation on the temporal trends of persistent halogenated compounds (PHCs) is necessary to predict their future impacts on the environment and human health and evaluate the effectiveness of regulations on their production and usage, it is of concern to investigate annual temporal trends of PHCs in biota samples. This study examined the temporal trends of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and perfluorinated compounds (PFCs) in Chinese sturgeon (Acipenser sinensis) eggs over a period of 25 years (1984-2008), and 62 PCBs (19.2-1030 ng/g dw for total PCBs), 16 PBDEs (4.7-572 ng/g dw for total PBDEs), and 14 PFCs (26-46 ng/g dw for total PFCs) were detected. Although a decreasing temporal trend was observed for total PCBs with annual reduction rate of 3.4% (ρ = 0.005), a clear break point was observed around 1991, indicating their continuing emission in the 1980s in China. All major PBDEs showed increasing temporal trends, with annual change rates at 3.5-10.2% over the 25 years, but a sharp decreasing trend was observed after 2006, indicating a rapid response to the banning of PBDE usage in China in 2004. The greatest annual rate of increase was observed for BDE-28 (10.2%) followed by BDE-100 (7.7%), which would be due to metabolism input from higher brominated PBDEs. Significantly increasing temporal trends were observed for all PFCs, and the annual rates of increase were 7.9% and 5.9% for total perfluorinated carboxylic acids and perfluorooctanesulfonate (PFOS), respectively. A peak concentration for PFOS was observed in 1989, which may be related to the import history of PFCs in China. The present study is the first report of systematic temporal trends of PHCs in biota samples from China and shows that regulatory policy is needed to reduce their potential health and ecological risk in China considering the increasing temporal trends of PBDEs and PFCs. PMID:25558919

  10. Temporal trends of polychlorinated biphenyls, polybrominated diphenyl ethers, and perfluorinated compounds in Chinese sturgeon (Acipenser sinensis) eggs (1984-2008).

    PubMed

    Jianxian, Sun; Hui, Peng; Jianying, Hu

    2015-02-01

    Because investigation on the temporal trends of persistent halogenated compounds (PHCs) is necessary to predict their future impacts on the environment and human health and evaluate the effectiveness of regulations on their production and usage, it is of concern to investigate annual temporal trends of PHCs in biota samples. This study examined the temporal trends of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and perfluorinated compounds (PFCs) in Chinese sturgeon (Acipenser sinensis) eggs over a period of 25 years (1984-2008), and 62 PCBs (19.2-1030 ng/g dw for total PCBs), 16 PBDEs (4.7-572 ng/g dw for total PBDEs), and 14 PFCs (26-46 ng/g dw for total PFCs) were detected. Although a decreasing temporal trend was observed for total PCBs with annual reduction rate of 3.4% (ρ = 0.005), a clear break point was observed around 1991, indicating their continuing emission in the 1980s in China. All major PBDEs showed increasing temporal trends, with annual change rates at 3.5-10.2% over the 25 years, but a sharp decreasing trend was observed after 2006, indicating a rapid response to the banning of PBDE usage in China in 2004. The greatest annual rate of increase was observed for BDE-28 (10.2%) followed by BDE-100 (7.7%), which would be due to metabolism input from higher brominated PBDEs. Significantly increasing temporal trends were observed for all PFCs, and the annual rates of increase were 7.9% and 5.9% for total perfluorinated carboxylic acids and perfluorooctanesulfonate (PFOS), respectively. A peak concentration for PFOS was observed in 1989, which may be related to the import history of PFCs in China. The present study is the first report of systematic temporal trends of PHCs in biota samples from China and shows that regulatory policy is needed to reduce their potential health and ecological risk in China considering the increasing temporal trends of PBDEs and PFCs.

  11. Focused ultrasound solid-liquid extraction for the determination of perfluorinated compounds in fish, vegetables and amended soil.

    PubMed

    Zabaleta, Itsaso; Bizkarguenaga, Ekhiñe; Iparragirre, Arantza; Navarro, Patricia; Prieto, Ailette; Fernández, Luis Ángel; Zuloaga, Olatz

    2014-02-28

    In the present work a method was developed for the determination of different perfluorinated compounds (PFCs), including three perfluorinated sulfonic acids (PFSAs), seven perfluorocarboxylic acids (PFCAs), three perfluorophosphonic acids (PFPAs) and perfluorooctanesulfonamide (PFOSA) in fish, vegetables and amended soil samples based on focused ultrasound solid-liquid extraction (FUSLE) followed by solid-phase extraction (SPE) clean-up and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Different variables affecting the chromatographic separation (column type and pH of the mobile phase), the electrospray ionization (capillary voltage, nebulizer pressure and drying gas flow) and mass spectrometric detection (fragmentor voltage and collision energy) were optimized in order to improve the sensitivity of the separation and detection steps. In the case of FUSLE variables such as the solvent type, the solvent volume, the extraction temperature, the sonication and extraction time and the percentage of applied irradiation power were studied. Under optimized conditions, sonication of 2.5min with pulse times on of 0.8s and pulse times off of 0.2s in 7mL of (9:1) acetonitrile (ACN): water mixture in duplicate guaranteed exhaustive extraction of the matrices analyzed. Due to the non-selective extraction using FUSLE, different SPE cartridges (200-mg Waters Oasis-HLB, 150-mg Waters Oasis-WAX and 150-mg Waters Oasis-MAX) were tested in terms of extraction efficiency and matrix effect both in the extraction and detection steps. Mix mode SPE using Waters Oasis-WAX provided the best extraction efficiencies with the lowest matrix effect. The final method was validated in terms of recovery at two fortification levels (in the 80-120% for most of the analytes and matrices), precision (relative standard deviation in the 2-15% range) and method detection limits (MDLs, 0.3-12.4ng/g for vegetables, 0.2-12.5ng/g for fish and 1-22ng/g for amended soil). Finally the method was

  12. Hexahydro-1,3,5-trinitro-1,3,5-triazine translocation in poplar trees

    SciTech Connect

    Thompson, P.L.; Ramer, L.A.; Schnoor, J.L.

    1999-02-01

    This article evaluates the translocation of the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in hybrid poplar trees (Populus deltoides x nigra, DN34) grown in hydroponic solutions. Mass balances with [U-{sup 14}C]RDX were used to assess RDX translocation. Up to 60% of the RDX uptaken by the tree accumulated in leaf tissues. Analysis of plant extracts by high-performance liquid chromatography equipped with radiochemical detection indicated that RDX was not significantly transformed during exposure periods of up to 7 d. The bioaccumulation of RDX may be an important concern for phytoremediation efforts.

  13. micrOMEGAs: Version 1.3

    NASA Astrophysics Data System (ADS)

    Bélanger, G.; Boudjema, F.; Pukhov, A.; Semenov, A.

    2006-04-01

    We present the latest version of micrOMEGAs, a code that calculates the relic density of the lightest supersymmetric particle (LSP) in the minimal supersymmetric standard model (MSSM). All tree-level processes for the annihilation of the LSP are included as well as all possible coannihilation processes with neutralinos, charginos, sleptons, squarks and gluinos. The cross-sections extracted from CalcHEP are calculated exactly using loop-corrected masses and mixings as specified in the SUSY Les Houches Accord. Relativistic formulae for the thermal average are used and care is taken to handle poles and thresholds by adopting specific integration routines. The input parameters can be either the soft SUSY parameters in a general MSSM or the parameters of a SUGRA model specified at the GUT scale. In the latter case, a link with Suspect, SOFTSUSY, Spheno and Isajet allows one to calculate the supersymmetric spectrum, Higgs masses, as well as mixing matrices. Higher-order corrections to Higgs couplings to quark pairs including QCD as well as some SUSY corrections ( Δm) are implemented. Routines calculating (, b→sγ and B→μμ are also included. In particular the b→sγ routine includes an improved NLO for the SM and the charged Higgs while the SUSY large tanβ effects beyond leading-order are included. This new version also provides cross-sections for any 2→2 process as well as partial decay widths for two-body final states in the MSSM allowing for easy simulation at colliders. Program summaryProgram title:micrOMEGAs1.3 Catalogue identifier:ADQR_v1_3 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADQR_v1_3 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions:none Computer:PC, Alpha, Silicon graphics, Sun Programming language:C and Fortran Operating system:UNIX (Linux, OSF1, IRIX64, SunOS) RAM:20 MB depending on the number of processes required No of lines in distributed program, including test data, etc

  14. Exposure to perfluorinated compounds in Catalonia, Spain, through consumption of various raw and cooked foodstuffs, including packaged food.

    PubMed

    Jogsten, Ingrid Ericson; Perelló, Gemma; Llebaria, Xavier; Bigas, Esther; Martí-Cid, Roser; Kärrman, Anna; Domingo, José L

    2009-07-01

    In this study, the role that some food processing and packaging might play as a source of perfluorinated compounds (PFCs) through the diet was assessed. The levels of PFCs were determined in composite samples of veal steak (raw, grilled, and fried), pork loin (raw, grilled, and fried), chicken breast (raw, grilled, and fried), black pudding (uncooked), liver lamb (raw), marinated salmon (home-made and packaged), lettuce (fresh and packaged), pate of pork liver, foie gras of duck, frankfurt, sausages, chicken nuggets (fried), and common salt. Among the 11 PFCs analyzed, only PFHxS, PFOS, PFHxA, and PFOA were detected in at least one composite sample, while the levels of the remaining PFCs (PFBuS, PFHpA, PFNA, PFDA, PFUnDA, and PFDoDA) were under their respective detection limits. PFOS was the compound most frequently detected, being found in 8 of the 20 food items analyzed, while PFHxA was detected in samples of raw veal, chicken nuggets, frankfurt, sausages, and packaged lettuce. According to the results of the present study, it is not sufficiently clear if cooking with non-stick cookware, or packaging some foods, could contribute to a higher human exposure to PFCs.

  15. First-flush loads of perfluorinated compounds in stormwater runoff from Hayabuchi River basin, Japan served by separated sewerage system.

    PubMed

    Zushi, Yasuyuki; Masunaga, Shigeki

    2009-08-01

    Worldwide environmental pollution by perfluorinated compounds (PFCs) has been reported. PFCs have also been reported to have nonpoint sources (NPSs). A fixed-point hourly monitoring in the river was conducted during a storm event using an automatic sampler to estimate the impact of the first-flush of PFCs from NPS in this study. Perfluorocarboxylates (PFCAs) and perfluoroalkyl sulfonates (PFASs) with different chain lengths were monitored. The concentrations of short- to medium-chain-length PFCAs such as PFHpA, PFOA and PFNA, and PFASs such as PFBS, PFPeS, PFHxS, PFHpS and PFOS showed no marked increase with the storm-runoff event. However, in contrast to this, concentrations of long-chain-length PFCAs such as PFDA and PFUnA increased markedly. The concentrations of PFDA and PFUnA increased 3.4 (1.5-5.0 ng L(-1))- and 2.0 (3.3-6.7 ng L(-1))-fold, respectively. This study demonstrates that large loads of long-chain-length PFCAs are discharged to the Hayabuchi River during the first-flush after the rain event.

  16. GIS-based source identification and apportionment of diffuse water pollution: perfluorinated compound pollution in the Tokyo Bay basin.

    PubMed

    Zushi, Yasuyuki; Masunaga, Shigeki

    2011-11-01

    To efficiently reduce perfluorinated compound (PFC) pollution, it is important to have an understanding of PFC sources and their contribution to the pollution. In this study, source identification of diffuse water pollution by PFCs was conducted using a GIS-based approach. Major components of the source identification were collection of the monitoring data and preparation of the corresponding geographic information that was extracted from a constructed GIS database. The spatially distributed pollution factors were then explored by multiple linear regression analysis, after which they were visually expressed using GIS. Among the 35 PFC homologues measured in a survey of the Tokyo Bay basin, 18 homologues were analyzed. Pollution by perfluorooctane sulfonate (PFOS) was explained well by the percentage of arterial traffic area in the basin, and the 84% variance of the measured PFOS concentration was explained by two geographic variables, arterial traffic area and population. Source apportionment between point and nonpoint sources was conducted based on the results of the analysis. The contribution of PFOS from nonpoint sources was comparable to that from point sources in several major rivers flowing into Tokyo Bay. Source identification and apportionment using the GIS-based approach was shown to be effective, especially for ubiquitous types of pollution, such as PFC pollution.

  17. Perfluorinated compounds in sediment samples from the wastewater canal of Pančevo (Serbia) industrial area.

    PubMed

    Beškoski, Vladimir P; Takemine, Shusuke; Nakano, Takeshi; Slavković Beškoski, Latinka; Gojgić-Cvijović, Gordana; Ilić, Mila; Miletić, Srdjan; Vrvić, Miroslav M

    2013-06-01

    Perfluoroalkyl sulfonates (PFSAs) and perfluoroalkyl carboxylates (PFCAs) were analyzed in sediment samples from the wastewater canal draining the industrial complex of Pančevo, Serbia (oil refinery, petrochemical plant, and fertilizer factory). The canal is directly connected to Europe's second largest river, the Danube, which drains its water into the Black Sea. Perfluorooctane sulfonate (PFOS) up to 5.7ngg(-1) dry weight (dw) and total Perfluorinated compounds (PFCs) up to 6.3ngg(-1) dw were detected. Compared to other reports, high levels of PFOS were found, even though PFCs are not used in the industrial production associated with this canal. The PFOS concentration in water was recalculated using the adsorption coefficient, KOC from literature. Using the average output of wastewater from the canal, a mass load of 1.38kg PFOS per year discharged in the Danube River has been calculated, which undoubtedly points to the contribution to global persistent organic pollution of surface waters originating from this industrial place. PMID:23415492

  18. Automated analysis of perfluorinated compounds in human hair and urine samples by turbulent flow chromatography coupled to tandem mass spectrometry.

    PubMed

    Perez, Francisca; Llorca, Marta; Farré, Marinella; Barceló, Damià

    2012-03-01

    Perfluorinated compounds (PFCs) are ubiquitous contaminants of humans and animals worldwide. PFCs are bioaccumulated because of their affinity for proteins. It has been shown they could have a variety of toxicological effects and cause damage to human health, emphasizing the need for sensitive and robust analytical methods to assess their bioaccumulation in humans. In this paper we report the development and validation of an analytical method for analysis of PFCs in the non-invasive human matrices hair and urine. The method is based on rapid and simple sample pre-treatment followed by online turbulent flow liquid chromatography and tandem mass spectrometry (TFC-LC-MS-MS) for analysis of 21 PFCs. The method was validated for both matrices. Percentage recovery was between 60 and 105 for most compounds in both matrices. Limits of quantification ranged from 0.1 to 9 ng mL(-1) in urine and from 0.04 to 13.4 in hair. The good performance of the method was proved by investigating the presence of selected PFCs in 24 hair and 30 urine samples from different donors living in Barcelona (NE Spain). The results were indicative of bioaccumulation of these compounds in both types of sample. PFOS and PFOA were most frequently detected in hair and PFBA in urine.

  19. Accumulation of perfluorinated compounds in captive Bengal tigers (Panthera tigris tigris) and African lions (Panthera leo Linnaeus) in China.

    PubMed

    Li, Xuemei; Yeung, Leo Wai Yin; Taniyasu, Sachi; Lam, Paul K S; Yamashita, Nobuyoshi; Xu, Muqi; Dai, Jiayin

    2008-11-01

    The accumulation of perfluorinated compounds (PFCs) in the sera of captive wildlife species Bengal tigers (Panthera tigris tigris) and African lions (Panthera leo Linnaeus) from Harbin Wildlife Park, Heilongjiang Province, in China were analyzed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Perfluorooctanesulfonate (PFOS) was the predominant contaminant with a mean serum concentration of 1.18 ng mL(-1) in tigers and 2.69 ng mL(-1) in lions. Perfluorononanoic acid (PFNA) was the second most prevalent contaminant in both species. The composition profiles of the tested PFCs differed between tigers and lions, and the percentages of perfluorooctanoic acid (PFOA) were greater in lions than in tigers, indicating different exposures and/or metabolic capabilities between the two species. Assessments of the risk of PFC contamination to the two species were obtained by comparing measured concentrations to points of departure or toxicity reference values (TRVs). Results suggest no risk of PFOS exposure or toxicity for the two species.

  20. Partitioning behavior of perfluorinated compounds between sediment and biota in the Pearl River Delta of South China.

    PubMed

    Zhao, Y G; Wan, H T; Wong, M H; Wong, Chris K C

    2014-06-15

    Surface sediment and biota were collected from 12 sampling sites - seven along the Pearl River Delta and five along the Hong Kong coastline. Perfluorinated compound (PFC) concentrations were detected using a high-performance-liquid-chromatogram-tandem-mass-spectrometry system. Analytical results indicated that the total PFC concentrations were in the range of 0.15-3.11 ng/g dry weight in sediments, while the total PFC concentrations in oyster and mussel samples were between 0.46-1.96 and 0.66-3.43 ng/g wet weight, respectively. The major types of PFCs detected in the sediment samples were perfluorooctanesulfonic acid (PFOS) and perfluorobutanoic acid (PFBA), with concentrations ranging from low limits of quantification to 0.86±0.12 ng/g dry weight and 1.50±0.26 ng/g dry weight, respectively. In bivalve samples, PFOS was the dominant contaminant with concentrations ranging from 0.25±0.09 to 0.83±0.12 ng/g wet weight in oysters and 0.41±0.14 to 1.47±0.25 ng/g wet weight in mussels. An increase in PFC concentration was found to be correlated with increased human population density in the study areas. PMID:24775068

  1. Characterization of the thermolysis products of Nafion membrane: A potential source of perfluorinated compounds in the environment

    NASA Astrophysics Data System (ADS)

    Feng, Mingbao; Qu, Ruijuan; Wei, Zhongbo; Wang, Liansheng; Sun, Ping; Wang, Zunyao

    2015-05-01

    The thermal decomposition of Nafion N117 membrane, a typical perfluorosulfonic acid membrane that is widely used in various chemical technologies, was investigated in this study. Structural identification of thermolysis products in water and methanol was performed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS). The fluoride release was studied using an ion-chromatography system, and the membrane thermal stability was characterized by thermogravimetric analysis. Notably, several types of perfluorinated compounds (PFCs) including perfluorocarboxylic acids were detected and identified. Based on these data, a thermolysis mechanism was proposed involving cleavage of both the polymer backbone and its side chains by attack of radical species. This is the first systematic report on the thermolysis products of Nafion by simulating its high-temperature operation and disposal process via incineration. The results of this study indicate that Nafion is a potential environmental source of PFCs, which have attracted growing interest and concern in recent years. Additionally, this study provides an analytical justification of the LC/ESI-MS/MS method for characterizing the degradation products of polymer electrolyte membranes. These identifications can substantially facilitate an understanding of their decomposition mechanisms and offer insight into the proper utilization and effective management on these membranes.

  2. Synthesis of 3-fluorobenzoyl chloride functionalized magnetic sorbent for highly efficient enrichment of perfluorinated compounds from river water samples.

    PubMed

    Yan, Zhihong; Cai, Ying; Zhu, Genhua; Yuan, Jinbin; Tu, Lidan; Chen, Chunyan; Yao, Shouzhuo

    2013-12-20

    A novel type of magnetic nanoparticles, 3-fluorobenzoyl chloride functionalized magnetic nanoparticles (Fe3O4@SiO2@FBC MNPs) was successfully synthesized. It was applied to the extraction and determination of perfluorinated compounds (PFCs) by coupling with ultra-high performance liquid chromatography with tandem triple quadrupole mass spectrometry (UHPLC-MS/MS). Due to the fluorous-fluorous interaction, the magnetic nanoparticles displayed excellent extraction performance for 6 PFCs, including perfluoroheptanoic acid (PFHpA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoA), perfluorotetradecanoic acid (PFTeDA), perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). The UHPLC separation of PFCs was very quick and could be achieved within 6min. Various factors that may influence the magnetic solid-phase extraction (MSPE) efficiency, such as sorbent amount, desorption solvent, extraction time, pH value of water samples and sample volume, were investigated in detail. Under the optimum conditions, the linear ranges of six PFCs were 0.25-25ng/L with the limits of detection (S/N=3) ranging from 0.01 to 0.06ng/L. Finally, the method was successfully applied to different river water samples, and the recoveries were in the range of 89.34-111.32%. These results indicated that the prepared Fe3O4@SiO2@FBC sorbents could efficiently enrich PFCs and that the proposed method is reliable.

  3. Estimated pKa values for the environmentally relevant C1 through C8 perfluorinated sulfonic acid isomers.

    PubMed

    Rayne, Sierra; Forest, Kaya

    2016-10-14

    In order to estimate isomer-specific acidity constants (pKa) for the perfluorinated sulfonic acid (PFSA) environmental contaminants, the parameterization method 6 (PM6) pKa prediction method was extensively validated against a wide range of carbon oxyacids and related sulfonic/sulfinic acids. Excellent pKa prediction performance was observed for the carbon oxyacids using the PM6 method, but this approach was found to have a severe positive bias for sulfonic/sulfinic acids. To overcome this obstacle, a correlation was developed between non-adjusted PM6 pKa values and the corresponding experimentally obtained/estimated acidity constants for a range of representative alkyl, aryl and halogen-substituted sulfonic acids. Application of this correction to the PM6 values allows for extension of this computational method to a new acid functional group. When used to estimate isomer-specific pKa values for the C1 through C8 PFSAs, the modified PM6 approach suggests an adjusted pKa range from -5.3 to -9.0, indicating that all members of this class of well-known environmental contaminants will be effectively completely dissociated in aquatic systems.

  4. Analysis of perfluorinated phosponic acids and perfluorooctane sulfonic acid in water, sludge and sediment by LC-MS/MS.

    PubMed

    Esparza, X; Moyano, E; de Boer, J; Galceran, M T; van Leeuwen, S P J

    2011-10-30

    Residues of perfluorinated phosphonic acids (PFPAs) and perfluorooctane sulfonic acid (PFOS) were investigated in various Dutch surface waters, sludge and sediments. For this purpose, a liquid chromatographic (LC) method was optimized by testing several columns with different mobile phases. Atmospheric pressure chemical ionization (APCI) was chosen for the LC tandem mass spectrometry (MS/MS) analysis. An ion-pair reagent was added to the injection solvent to improve peak shape. Different solvents were studied for the extraction from solid samples. For clean-up and pre-concentration, weak anion-exchange solid-phase extraction cartridges were used. Water samples were extracted using the same cartridges. The method was used for screening PFPAs in the Dutch aquatic environment. PFPAs were not observed in sediment or sludge samples. PFOPA was found at 1 ng L(-1) in one surface water sample. PFOS was found at levels between 0.07 ng g(-1) and 48 ng g(-1) (dry weight) in sediments and sewage sludge samples. PFOS concentrations in surface water ranged from 3.3 ng L(-1) to 25.4 ng L(-1).

  5. Spatial and temporal patterns in concentrations of perfluorinated compounds in bald eagle nestlings in the upper Midwestern United States.

    PubMed

    Route, William T; Russell, Robin E; Lindstrom, Andrew B; Strynar, Mark J; Key, Rebecca L

    2014-06-17

    Perfluorinated chemicals (PFCs) are of concern due to their widespread use, persistence in the environment, tendency to accumulate in animal tissues, and growing evidence of toxicity. Between 2006 and 2011 we collected blood plasma from 261 bald eagle nestlings in six study areas from the upper Midwestern United States. Samples were assessed for levels of 16 different PFCs. We used regression analysis in a Bayesian framework to evaluate spatial and temporal trends for these analytes. We found levels as high as 7370 ng/mL for the sum of all 16 PFCs (∑PFCs). Perfluorooctanesulfonate (PFOS) and perfluorodecanesulfonate (PFDS) were the most abundant analytes, making up 67% and 23% of the PFC burden, respectively. Levels of ∑PFC, PFOS, and PFDS were highest in more urban and industrial areas, moderate on Lake Superior, and low on the remote upper St. Croix River watershed. We found evidence of declines in ∑PFCs and seven analytes, including PFOS, PFDS, and perfluorooctanoic acid (PFOA); no trend in two analytes; and increases in two analytes. We argue that PFDS, a long-chained PFC with potential for high bioaccumulation and toxicity, should be considered for future animal and human studies.

  6. Rapid fabrication of microfluidic polymer electrolyte membrane fuel cell in PDMS by surface patterning of perfluorinated ion-exchange resin

    NASA Astrophysics Data System (ADS)

    Song, Yong-Ak; Batista, Candy; Sarpeshkar, Rahul; Han, Jongyoon

    In this paper we demonstrate a simple and rapid fabrication method for a microfluidic polymer electrolyte membrane (PEM) fuel cell using polydimethylsiloxane (PDMS), which has become the de facto standard material in BioMEMS. Instead of integrating a Nafion sheet film between two layers of a PDMS device in a traditional "sandwich format," we pattern a perfluorinated ion-exchange resin such as a Nafion resin on a glass substrate using a reversibly bonded PDMS microchannel to generate an ion-selective membrane between the fuel-cell electrodes. After this patterning step, the assembly of the microfluidic fuel cell is accomplished by simple oxygen plasma bonding between the PDMS chip and the glass substrate. In an example implementation, the planar PEM microfluidic fuel cell generates an open circuit voltage of 600-800 mV and delivers a maximum current output of nearly 4 μA. To enhance the power output of the fuel cell we utilize self-assembled colloidal arrays as a support matrix for the Nafion resin. Such arrays allow us to increase the thickness of the ion-selective membrane to 20 μm and increase the current output by 166%. Our novel fabrication method enables rapid prototyping of microfluidic fuel cells to study various ion-exchange resins for the polymer electrolyte membrane. Our work will facilitate the development of miniature, implantable, on-chip power sources for biomedical applications.

  7. Complete Defluorination of Perfluorinated Compounds by Hydrated Electrons Generated from 3-Indole-acetic-acid in Organomodified Montmorillonite

    NASA Astrophysics Data System (ADS)

    Tian, Haoting; Gao, Juan; Li, Hui; Boyd, Stephen A.; Gu, Cheng

    2016-09-01

    Here we describe a unique process that achieves complete defluorination and decomposition of perfluorinated compounds (PFCs) which comprise one of the most recalcitrant and widely distributed classes of toxic pollutant chemicals found in natural environments. Photogenerated hydrated electrons derived from 3-indole-acetic-acid within an organomodified clay induce the reductive defluorination of co-sorbed PFCs. The process proceeds to completion within a few hours under mild reaction conditions. The organomontmorillonite clay promotes the formation of highly reactive hydrated electrons by stabilizing indole radical cations formed upon photolysis, and prevents their deactivation by reaction with protons or oxygen. In the constrained interlayer regions of the clay, hydrated electrons and co-sorbed PFCs are brought in close proximity thereby increasing the probability of reaction. This novel green chemistry provides the basis for in situ and ex situ technologies to treat one of the most troublesome, recalcitrant and ubiquitous classes of environmental contaminants, i.e., PFCs, utilizing innocuous reagents, naturally occurring materials and mild reaction conditions.

  8. Complete Defluorination of Perfluorinated Compounds by Hydrated Electrons Generated from 3-Indole-acetic-acid in Organomodified Montmorillonite.

    PubMed

    Tian, Haoting; Gao, Juan; Li, Hui; Boyd, Stephen A; Gu, Cheng

    2016-01-01

    Here we describe a unique process that achieves complete defluorination and decomposition of perfluorinated compounds (PFCs) which comprise one of the most recalcitrant and widely distributed classes of toxic pollutant chemicals found in natural environments. Photogenerated hydrated electrons derived from 3-indole-acetic-acid within an organomodified clay induce the reductive defluorination of co-sorbed PFCs. The process proceeds to completion within a few hours under mild reaction conditions. The organomontmorillonite clay promotes the formation of highly reactive hydrated electrons by stabilizing indole radical cations formed upon photolysis, and prevents their deactivation by reaction with protons or oxygen. In the constrained interlayer regions of the clay, hydrated electrons and co-sorbed PFCs are brought in close proximity thereby increasing the probability of reaction. This novel green chemistry provides the basis for in situ and ex situ technologies to treat one of the most troublesome, recalcitrant and ubiquitous classes of environmental contaminants, i.e., PFCs, utilizing innocuous reagents, naturally occurring materials and mild reaction conditions. PMID:27608658

  9. Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and perfluorinated alkylated substances (PFASs) in traditional seafood items from western Greenland.

    PubMed

    Carlsson, Pernilla; Herzke, Dorte; Kallenborn, Roland

    2014-03-01

    In this study, contamination levels were determined for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and perfluorinated alkylated substances (PFASs) in traditional Greenland seafood items, such as raw and smoked fish fillet (salmon and halibut), whale and seal meat and narwhal mattak (skin and blubber). The daily intake of PCBs, PBDEs and PFASs through traditional seafood items in Greenland was assessed. Based on the presented levels of contaminants, in combination with earlier food intake studies, suggests that the daily exposure was below the tolerable daily intake threshold for all compounds. BDE-47 was the only PBDE-congener detected in all food items, except in smoked halibut. The levels of BDE-47 varied from < LOD in smoked halibut up to 18 ng/g lw in narwhal mattak and 21 ng/g lw in whale beef. ∑PCB were lowest in smoked halibut (37 ng/g lw) and highest in narwhal mattak with 1,146 ng/g lw. Perfluorooctane sulfonate (PFOS) was the most common of the PFASs. However, ΣPFASs were below detection limits in most fish fillet samples, and varied from 2.9 ng/g ww in whale beef to 13.5 ng/g ww in seal beef. The present study shows that the exclusion from the diet of local food items such as intestines and blubber have a strong positive effect for the reduction of POPs levels in food, without a reducing the health benefits of traditional food intake considerably. PMID:24352552

  10. Perfluorinated acids in air, rain, snow, surface runoff, and lakes: relative importance of pathways to contamination of urban lakes.

    PubMed

    Kim, Seung-Kyu; Kannan, Kurunthachalam

    2007-12-15

    Concentrations of perfluorinated acids (PFAs) were measured in various environmental matrices (air, rain, snow, surface runoff water, and lake water) in an urban area, to enable identification of sources and pathways of PFAs to urban water bodies. Total PFA concentrations ranged from 8.28 to 16.0 pg/ m3 (mean 11.3) in bulk air (sum of vapor and particulate phases), 0.91 to 13.2 ng/L (6.19) in rainwater, 0.91 to 23.9 ng/L (7.98) in snow, 1.11-81.8 ng/L (15.1 ng/L) in surface runoff water (SRW), and 9.49 to 35.9 ng/L (21.8) in lake water. Perfluorooctanoic acid (PFOA) was the predominant compound, accounting for > 35% of the total PFA concentrations, in all environmental matrices analyzed. Concentrations and relative compositions of PFAs in SRW were similar to those found for urban lakes. SRW contributes to contamination by PFOA in urban lakes. The measured concentration ratios of FTOH to PFOA in air were 1-2 orders of magnitude lower than the ratios calculated based on an assumption of exclusive atmospheric oxidation of FTOHs. Nevertheless, the mass balance analysis suggested the presence of an unknown input pathway that could contribute to a significant amount of total PFOA loadings to the lake. Flux estimates of PFOA at the air-water interface in the urban lake suggest net volatilization from water.

  11. Spatial and temporal patterns in concentrations of perfluorinated compounds in bald eagle nestlings in the Upper Midwestern United States

    USGS Publications Warehouse

    Route, William T.; Russell, Robin E.; Lindstrom, Andrew B.; Strynor, Mark J.; Key, Rebecca L.

    2014-01-01

    Perfluorinated chemicals (PFCs) are of concern due to their widespread use, persistence in the environment, tendency to accumulate in animal tissues, and growing evidence of toxicity. Between 2006 and 2011 we collected blood plasma from 261 bald eagle nestlings in six study areas from the upper Midwestern United States. Samples were assessed for levels of 16 different PFCs. We used regression analysis in a Bayesian framework to evaluate spatial and temporal trends for these analytes. We found levels as high as 7370 ng/mL for the sum of all 16 PFCs (∑PFCs). Perfluorooctanesulfonate (PFOS) and perfluorodecanesulfonate (PFDS) were the most abundant analytes, making up 67% and 23% of the PFC burden, respectively. Levels of ∑PFC, PFOS, and PFDS were highest in more urban and industrial areas, moderate on Lake Superior, and low on the remote upper St. Croix River watershed. We found evidence of declines in ∑PFCs and seven analytes, including PFOS, PFDS, and perfluorooctanoic acid (PFOA); no trend in two analytes; and increases in two analytes. We argue that PFDS, a long-chained PFC with potential for high bioaccumulation and toxicity, should be considered for future animal and human studies.

  12. Perfluorinated compound concentrations in great blue heron eggs near St. Paul, Minnesota, USA, in 1993 and 2010-2011

    USGS Publications Warehouse

    Custer, Thomas W.; Dummer, Paul M.; Custer, Christine M.; Wu, Qian; Kannan, Kurunthachalam; Trowbridge, Annette

    2013-01-01

    A great blue heron (Ardea herodias) colony on Pig's Eye Island on the Mississippi River near St. Paul, Minnesota, USA, is located near several potential perfluorinated compound (PFC) sources. The PFC concentrations in great blue heron eggs reported from a 1993 collection from the Pig's Eye colony were among the highest measured in bird eggs worldwide. The objective of this investigation was to determine whether PFC concentrations in great blue heron eggs at the Pig's Eye colony have changed since 1993. Total PFC concentrations in great blue heron eggs collected at the Pig's Eye colony in 2010 and 2011 (geometric mean = 340 and 492 ng/g wet wt) were 60% lower than the 1993 collection (1,015 ng/g wet wt). Among PFCs, perfluoroalkyl sulfonate concentrations were lower and perfluoroalkyl carboxylate concentrations were higher in the 2010 and 2011 collections. Two of 20 (10%) of the eggs analyzed from Pig's Eye in 2010 and 2011 were >1,000 ng PFCs/g wet weight and the maximum PFC value (2,506 ng PFCs/g wet wt) measured in 2010 and 2011 was among the highest PFC concentration reported in bird eggs. These high concentrations are at levels associated with physiological and neurological effects in birds.

  13. Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and perfluorinated alkylated substances (PFASs) in traditional seafood items from western Greenland.

    PubMed

    Carlsson, Pernilla; Herzke, Dorte; Kallenborn, Roland

    2014-03-01

    In this study, contamination levels were determined for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and perfluorinated alkylated substances (PFASs) in traditional Greenland seafood items, such as raw and smoked fish fillet (salmon and halibut), whale and seal meat and narwhal mattak (skin and blubber). The daily intake of PCBs, PBDEs and PFASs through traditional seafood items in Greenland was assessed. Based on the presented levels of contaminants, in combination with earlier food intake studies, suggests that the daily exposure was below the tolerable daily intake threshold for all compounds. BDE-47 was the only PBDE-congener detected in all food items, except in smoked halibut. The levels of BDE-47 varied from < LOD in smoked halibut up to 18 ng/g lw in narwhal mattak and 21 ng/g lw in whale beef. ∑PCB were lowest in smoked halibut (37 ng/g lw) and highest in narwhal mattak with 1,146 ng/g lw. Perfluorooctane sulfonate (PFOS) was the most common of the PFASs. However, ΣPFASs were below detection limits in most fish fillet samples, and varied from 2.9 ng/g ww in whale beef to 13.5 ng/g ww in seal beef. The present study shows that the exclusion from the diet of local food items such as intestines and blubber have a strong positive effect for the reduction of POPs levels in food, without a reducing the health benefits of traditional food intake considerably.

  14. Spatial and temporal patterns in concentrations of perfluorinated compounds in bald eagle nestlings in the upper Midwestern United States.

    PubMed

    Route, William T; Russell, Robin E; Lindstrom, Andrew B; Strynar, Mark J; Key, Rebecca L

    2014-06-17

    Perfluorinated chemicals (PFCs) are of concern due to their widespread use, persistence in the environment, tendency to accumulate in animal tissues, and growing evidence of toxicity. Between 2006 and 2011 we collected blood plasma from 261 bald eagle nestlings in six study areas from the upper Midwestern United States. Samples were assessed for levels of 16 different PFCs. We used regression analysis in a Bayesian framework to evaluate spatial and temporal trends for these analytes. We found levels as high as 7370 ng/mL for the sum of all 16 PFCs (∑PFCs). Perfluorooctanesulfonate (PFOS) and perfluorodecanesulfonate (PFDS) were the most abundant analytes, making up 67% and 23% of the PFC burden, respectively. Levels of ∑PFC, PFOS, and PFDS were highest in more urban and industrial areas, moderate on Lake Superior, and low on the remote upper St. Croix River watershed. We found evidence of declines in ∑PFCs and seven analytes, including PFOS, PFDS, and perfluorooctanoic acid (PFOA); no trend in two analytes; and increases in two analytes. We argue that PFDS, a long-chained PFC with potential for high bioaccumulation and toxicity, should be considered for future animal and human studies. PMID:24898913

  15. Application of WWTP biosolids and resulting perfluorinated compound contamination of surface and well water in Decatur, Alabama, USA.

    PubMed

    Lindstrom, Andrew B; Strynar, Mark J; Delinsky, Amy D; Nakayama, Shoji F; McMillan, Larry; Libelo, E Laurence; Neill, Michael; Thomas, Lee

    2011-10-01

    Perfluorinated chemicals (PFCs) such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been produced and used in a wide range of industrial and consumer products for many decades. Their resistance to degradation has led to their widespread distribution in the environment, but little is known about how humans become exposed. Recent studies have demonstrated that the application of PFC contaminated biosolids can have important effects on local environments, ultimately leading to demonstrable human exposures. This manuscript describes a situation in Decatur, Alabama where PFC contaminated biosolids from a local municipal wastewater treatment facility that had received waste from local fluorochemical facilities were used as a soil amendment in local agricultural fields for as many as twelve years. Ten target PFCs were measured in surface and groundwater samples. Results show that surface and well water in the vicinity of these fields had elevated PFC concentrations, with 22% of the samples exceeding the U.S. Environmental Protection Agency's Provisional Health Advisory level for PFOA in drinking water of 400 ng/L. Water/soil concentration ratios as high as 0.34 for perfluorohexanoic acid, 0.17 for perfluoroheptanoic acid, and 0.04 for PFOA verify decreasing mobility from soils with increasing chain length while indicating that relatively high transport from soils to surface and well water is possible.

  16. Risk assessment for human consumption of perfluorinated compound-contaminated freshwater and marine fish from Hong Kong and Xiamen.

    PubMed

    Zhao, Yin G; Wan, Hin T; Law, Alice Y S; Wei, Xi; Huang, Ye Q; Giesy, John P; Wong, Ming H; Wong, Chris K C

    2011-09-01

    Perfluorinated compounds (PFCs) are man-made fluoro-surfactants that are identified as global pollutants and can pose health risks to humans and wildlife. Two aspects of risk assessment were conducted in this study, including exposure and response. Exposure was estimated by using the concentrations of PFCs in fish and applying standard exposure factors. Among different PFCs, PFOS, PFOA, PFNA, PFDA, PFUdA and PFTrDA were detected. Total concentrations of PFC in fish ranged from 0.27-8.4 ng g(-1) to 0.37-8.7 ng g(-1) respectively in Hong Kong and Xiamen. The calculated hazard ratio (HR) of PFOS for all fish was less than 1.0. However, the HR for mandarin fish in Hong Kong and bighead carp, grass carp and tilapia in Xiamen, had HR values of approximately 0.5, indicating that frequent consumption of these 4 more contaminated fish species might pose an unacceptable risk to human health. Our data support the notion that the released/disposed chemical pollutants into water systems make fish a source of environmental toxicants to humans. The risks and potential effects of PFCs to health of coastal population in the Pearl River Delta are of concern. PMID:21705041

  17. Influence of salinity and temperature on uptake of perfluorinated carboxylic acids (PFCAs) by hydroponically grown wheat (Triticum aestivum L.).

    PubMed

    Zhao, Hongxia; Qu, Baocheng; Guan, Yue; Jiang, Jingqiu; Chen, Xiuying

    2016-01-01

    Perfluoroalkyl substances (PFASs) have recently attracted increasing concerns due to their ubiquitous existence, adverse effects and persistence in environment. This study employed four perfluorinated carboxylic acids (PFCAs) to examine effects of salinity and temperature on the PFAS uptake in wheat, one of the major crops in the North China Plain. Wheat plants were grown in the spiked-PFCA hydroponic culture system at different salinities and temperatures. As expected, salinity and temperature significantly impacted the root uptake and translocation of wheat to four PFCAs, and the concentrations for each of PFCAs in wheat root and shoot increased with increasing salinity and temperature, respectively. PFCA concentrations at high salinity or high temperature were up to thrice those found at low salinity or low temperature. Except for perfluorobutanoic acid, the amount of PFCAs in root was always higher than that in shoot at the ranges of salinity and temperature tested. Additionally salinity and temperature were also capable of influencing the transfer factors (TFs) of four PFCAs, and significant increase was observed in the TFs in response to the increases in salinity and temperature.

  18. Concentrations and trends of perfluorinated chemicals in potential indoor sources from 2007 through 2011 in the US.

    PubMed

    Liu, Xiaoyu; Guo, Zhishi; Krebs, Kenneth A; Pope, Robert H; Roache, Nancy F

    2014-03-01

    Certain perfluorinated chemicals (PFCs) in consumer products used indoors are potential indoor PFCs sources and have been associated with developmental toxicity and other adverse health effects in laboratory animals (Lao et al., 2007). The concentrations of selected PFCs including perfluorooctanoic acid (PFOA) and other perfluorocarboxylic acids (PFCAs), in 35 selected consumer products that are commonly used in indoors were measured from the year of 2007 through 2011. The products collected included carpet, commercial carpet-care liquids, household carpet/fabric-care liquids, treated apparel, treated home textiles, treated non-woven medical garments, floor waxes, food-contact paper, membranes for apparel, and thread-sealant tapes. They were purchased from retail outlets in the United States between March 2007 and September 2011. The perfluorocarboxylic acid (PFCA) contents in the products have shown an overall downward trend. However, PFOA (C8) could still be detected in many products that we analyzed. Reductions of PFCAs were shown in both short-chain PFCAs (sum of C4 to C7) and long-chain PFCAs (sum of C8 to C12) over the study period. There were no significant changes observed between short-chain PFCAs and long-chain PFCAs. Fourteen products were analyzed to determine the amounts of perfluoroalkyl sulfonates (PFASs) they contained. These limited data show the pronounced increase of perfluoro-butane sulfonate (PFBS), an alternative to perfluorooctanoic sulfonate (PFOS), in the samples. A longer and wider range of study will be required to confirm this observed trend. PMID:24268172

  19. Estimated pKa values for the environmentally relevant C1 through C8 perfluorinated sulfonic acid isomers.

    PubMed

    Rayne, Sierra; Forest, Kaya

    2016-10-14

    In order to estimate isomer-specific acidity constants (pKa) for the perfluorinated sulfonic acid (PFSA) environmental contaminants, the parameterization method 6 (PM6) pKa prediction method was extensively validated against a wide range of carbon oxyacids and related sulfonic/sulfinic acids. Excellent pKa prediction performance was observed for the carbon oxyacids using the PM6 method, but this approach was found to have a severe positive bias for sulfonic/sulfinic acids. To overcome this obstacle, a correlation was developed between non-adjusted PM6 pKa values and the corresponding experimentally obtained/estimated acidity constants for a range of representative alkyl, aryl and halogen-substituted sulfonic acids. Application of this correction to the PM6 values allows for extension of this computational method to a new acid functional group. When used to estimate isomer-specific pKa values for the C1 through C8 PFSAs, the modified PM6 approach suggests an adjusted pKa range from -5.3 to -9.0, indicating that all members of this class of well-known environmental contaminants will be effectively completely dissociated in aquatic systems. PMID:27389973

  20. Complete Defluorination of Perfluorinated Compounds by Hydrated Electrons Generated from 3-Indole-acetic-acid in Organomodified Montmorillonite

    PubMed Central

    Tian, Haoting; Gao, Juan; Li, Hui; Boyd, Stephen A.; Gu, Cheng

    2016-01-01

    Here we describe a unique process that achieves complete defluorination and decomposition of perfluorinated compounds (PFCs) which comprise one of the most recalcitrant and widely distributed classes of toxic pollutant chemicals found in natural environments. Photogenerated hydrated electrons derived from 3-indole-acetic-acid within an organomodified clay induce the reductive defluorination of co-sorbed PFCs. The process proceeds to completion within a few hours under mild reaction conditions. The organomontmorillonite clay promotes the formation of highly reactive hydrated electrons by stabilizing indole radical cations formed upon photolysis, and prevents their deactivation by reaction with protons or oxygen. In the constrained interlayer regions of the clay, hydrated electrons and co-sorbed PFCs are brought in close proximity thereby increasing the probability of reaction. This novel green chemistry provides the basis for in situ and ex situ technologies to treat one of the most troublesome, recalcitrant and ubiquitous classes of environmental contaminants, i.e., PFCs, utilizing innocuous reagents, naturally occurring materials and mild reaction conditions. PMID:27608658

  1. An Assessment of Perfluorinated Organic Compounds and the Potentail Impacts to Water Quality and Biota in Coastal Ecosystems

    NASA Astrophysics Data System (ADS)

    Erhunse, A.; Gragg, R.

    2006-12-01

    Urbanized estuaries are well-documented to have elevated contaminant levels in sediments, water and associated biota. Most previous research efforts examining the effects of anthropogenic contamination in urbanized estuaries has focused on persistent priority pollutants, such as trace metals, pesticides, PCBs and PAHs. Recently, concerns have been raised about the occurrence, transport and distribution and effects of emerging contaminants being released into coastal watersheds through upland runoff from both urban and agricultural lands, sewage discharges, industrial releases, and aquaculture. Apalachicola Bay a major estuarine, commercial and recreational seafood resource is the endpoint of the Apalachicola-Chattahoochee-Flint River Basin. Today the river basin encapsulates a vast and evolving expanse of agricultural, urban, industrial, silvaculture, and natural landscapes and activities. The purpose of this study is to monitor the occurrence of an emerging class of compounds (perfluorinated organic compounds) in the Apalachicola Bay watershed. Given the dynamic growth and development up river from the Bay organic substances (lipophillic and water soluble compounds) inputs may be increasing and impacting the ecology of the Bay which compared to other bay areas is at this time relatively pristine. This issue can be investigated utilizing in-situ permeable membrane sampling devices specific for lipophillic and water-soluble compounds in concert with sediment samples. The results may serve as a baseline for the hypothesized increase in inputs coinciding with upstream and coastal development.

  2. Characterization of the thermolysis products of Nafion membrane: A potential source of perfluorinated compounds in the environment.

    PubMed

    Feng, Mingbao; Qu, Ruijuan; Wei, Zhongbo; Wang, Liansheng; Sun, Ping; Wang, Zunyao

    2015-01-01

    The thermal decomposition of Nafion N117 membrane, a typical perfluorosulfonic acid membrane that is widely used in various chemical technologies, was investigated in this study. Structural identification of thermolysis products in water and methanol was performed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS). The fluoride release was studied using an ion-chromatography system, and the membrane thermal stability was characterized by thermogravimetric analysis. Notably, several types of perfluorinated compounds (PFCs) including perfluorocarboxylic acids were detected and identified. Based on these data, a thermolysis mechanism was proposed involving cleavage of both the polymer backbone and its side chains by attack of radical species. This is the first systematic report on the thermolysis products of Nafion by simulating its high-temperature operation and disposal process via incineration. The results of this study indicate that Nafion is a potential environmental source of PFCs, which have attracted growing interest and concern in recent years. Additionally, this study provides an analytical justification of the LC/ESI-MS/MS method for characterizing the degradation products of polymer electrolyte membranes. These identifications can substantially facilitate an understanding of their decomposition mechanisms and offer insight into the proper utilization and effective management on these membranes.

  3. Accumulation of perfluorinated compounds in captive Bengal tigers (Panthera tigris tigris) and African lions (Panthera leo Linnaeus) in China.

    PubMed

    Li, Xuemei; Yeung, Leo Wai Yin; Taniyasu, Sachi; Lam, Paul K S; Yamashita, Nobuyoshi; Xu, Muqi; Dai, Jiayin

    2008-11-01

    The accumulation of perfluorinated compounds (PFCs) in the sera of captive wildlife species Bengal tigers (Panthera tigris tigris) and African lions (Panthera leo Linnaeus) from Harbin Wildlife Park, Heilongjiang Province, in China were analyzed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Perfluorooctanesulfonate (PFOS) was the predominant contaminant with a mean serum concentration of 1.18 ng mL(-1) in tigers and 2.69 ng mL(-1) in lions. Perfluorononanoic acid (PFNA) was the second most prevalent contaminant in both species. The composition profiles of the tested PFCs differed between tigers and lions, and the percentages of perfluorooctanoic acid (PFOA) were greater in lions than in tigers, indicating different exposures and/or metabolic capabilities between the two species. Assessments of the risk of PFC contamination to the two species were obtained by comparing measured concentrations to points of departure or toxicity reference values (TRVs). Results suggest no risk of PFOS exposure or toxicity for the two species. PMID:18789477

  4. Influence of salinity and temperature on uptake of perfluorinated carboxylic acids (PFCAs) by hydroponically grown wheat (Triticum aestivum L.).

    PubMed

    Zhao, Hongxia; Qu, Baocheng; Guan, Yue; Jiang, Jingqiu; Chen, Xiuying

    2016-01-01

    Perfluoroalkyl substances (PFASs) have recently attracted increasing concerns due to their ubiquitous existence, adverse effects and persistence in environment. This study employed four perfluorinated carboxylic acids (PFCAs) to examine effects of salinity and temperature on the PFAS uptake in wheat, one of the major crops in the North China Plain. Wheat plants were grown in the spiked-PFCA hydroponic culture system at different salinities and temperatures. As expected, salinity and temperature significantly impacted the root uptake and translocation of wheat to four PFCAs, and the concentrations for each of PFCAs in wheat root and shoot increased with increasing salinity and temperature, respectively. PFCA concentrations at high salinity or high temperature were up to thrice those found at low salinity or low temperature. Except for perfluorobutanoic acid, the amount of PFCAs in root was always higher than that in shoot at the ranges of salinity and temperature tested. Additionally salinity and temperature were also capable of influencing the transfer factors (TFs) of four PFCAs, and significant increase was observed in the TFs in response to the increases in salinity and temperature. PMID:27186505

  5. Strain-accelerated formation of chiral, optically active buta-1,3-dienes.

    PubMed

    Chiu, Melanie; Tchitchanov, Boris H; Zimmerli, Daniel; Sanhueza, Italo A; Schoenebeck, Franziska; Trapp, Nils; Schweizer, W Bernd; Diederich, François

    2015-01-01

    The formal [2+2] cycloaddition-retroelectrocyclization (CA-RE) reactions between tetracyanoethylene (TCNE) and strained, electron-rich dibenzo-fused cyclooctynes were studied. The effect of ring strain on the reaction kinetics was quantified, revealing that the rates of cycloaddition using strained, cyclic alkynes are up to 5500 times greater at 298 K than those of reactions using unstrained alkynes. Cyclobutene reaction intermediates, as well as buta-1,3-diene products, were isolated and their structures were studied crystallographically. Isolation of a rare example of a chiral buta-1,3-diene that is optically active and configurationally stable at room temperature is reported. Computational studies on the enantiomerization pathway of the buta-1,3-diene products showed that the eight-membered ring inverts via a boat conformer in a ring-flip mechanism. In agreement with computed values, experimentally measured activation barriers of racemization in these compounds were found to be up to 26 kcal mol(-1) . PMID:25425560

  6. Study of the surface modification of LiNi1/3Co1/3Mn1/3O2 cathode material for lithium ion battery

    NASA Astrophysics Data System (ADS)

    Hashem, A. M. A.; Abdel-Ghany, A. E.; Eid, A. E.; Trottier, J.; Zaghib, K.; Mauger, A.; Julien, C. M.

    2011-10-01

    The surface of LiNi1/3Co1/3Mn1/3O2 (LNMCO) particles has been studied for material synthesized at 900 °C by a two-step process from a mixture of LiOH·H2O and metal oxalate [(Ni1/3Co1/3Mn1/3)C2O4] obtained by co-precipitation. Samples have been characterized by X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), Raman scattering (RS) spectroscopy, and magnetic measurements. We have investigated the effect of the heat treatment of particles at 600 °C with organic substances such as sucrose and starch. HRTEM images and RS spectra indicate that the surface of particles has been modified. The annealing does not lead to any carbon coating but it leads to the crystallization of the thin disordered layer on the surface of LiNi1/3Co1/3Mn1/3O2. The beneficial effect has been tested on the electrochemical properties of the LiNi1/3Co1/3Mn1/3O2 cathode materials. The capacity at 10C-rate is enhanced by 20% for post-treated LNMCO particles at 600 °C for half-an-hour.

  7. Equation of state for fused-hard-sphere fluid mixtures

    NASA Astrophysics Data System (ADS)

    Largo, J.; Solana, J. R.

    This paper develops a theoretically-based equation of state for fused-hard-sphere fluid mixtures on the basis of an equation of state previously derived for hard-convex-body fluid mixtures. The equation uses as a reference the equation of state for an equivalent hard-sphere fluid mixture in which each component has the same molecular volume as the effective molecular volume of one of the components of the fused-hard-sphere mixture. The two parameters required by the theory, namely the averaged effective molecular volume of the molecules in the mixture and the corresponding effective non-sphericity parameter, are obtained from the geometrical characteristics of the molecules that form the mixture. The results are, on the whole, in closer agreement with simulation data than those obtained with other theories developed for this kind of mixture.

  8. HVI Ballistic Limit Charaterization of Fused Silica Thermal Pane

    NASA Technical Reports Server (NTRS)

    Bohl, William E.; Miller, Joshua E.; Christiansen, Eric L.; Deighton, Kevin.; Davis, Bruce

    2015-01-01

    The Orion spacecraft's windows are exposed to the micrometeroid and orbital debris (MMOD) space environments while in space as well as the Earth entry environment at the mission's conclusion. The need for a low-mass spacecraft window design drives the need to reduce conservatism when assessing the design for loss of crew due to MMOD impact and subsequent Earth entry. Therefore, work is underway at NASA and Lockheed Martin to improve characterization of the complete penetration ballistic limit of an outer fused silica thermal pane. Hypervelocity impact tests of the window configuration at up to 10 km/s and hydrocode modeling have been performed with a variety of projectile materials to enable refinement of the fused silica ballistic limit equation.

  9. Depth-fused 3D imagery on an immaterial display.

    PubMed

    Lee, Cha; Diverdi, Stephen; Höllerer, Tobias

    2009-01-01

    We present an immaterial display that uses a generalized form of depth-fused 3D (DFD) rendering to create unencumbered 3D visuals. To accomplish this result, we demonstrate a DFD display simulator that extends the established depth-fused 3D principle by using screens in arbitrary configurations and from arbitrary viewpoints. The feasibility of the generalized DFD effect is established with a user study using the simulator. Based on these results, we developed a prototype display using one or two immaterial screens to create an unencumbered 3D visual that users can penetrate, examining the potential for direct walk-through and reach-through manipulation of the 3D scene. We evaluate the prototype system in formative and summative user studies and report the tolerance thresholds discovered for both tracking and projector errors.

  10. Mechanical protection of DLC films on fused silica slides

    NASA Technical Reports Server (NTRS)

    Nir, D.

    1985-01-01

    Measurements were made with a new test for improved quantitative estimation of the mechanical protection of thin films on optical materials. The mechanical damage was induced by a sand blasting system using spherical glass beads. Development of the surface damage was measured by the changes in the specular transmission and reflection, and by inspection using a surface profilometer and a scanning electron microscope. The changes in the transmittance versus the duration of sand blasting was measured for uncoated fused silica slides and coated ones. It was determined that the diamond like carbon films double the useful optical lifetime of the fused silica. Theoretical expressions were developed to describe the stages in surface deterioration. Conclusions were obtained for the SiO2 surface mechanism and for the film removal mechanism.

  11. 30 CFR 75.601-3 - Short circuit protection; dual element fuses; current ratings; maximum values.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Short circuit protection; dual element fuses... Trailing Cables § 75.601-3 Short circuit protection; dual element fuses; current ratings; maximum values. Dual element fuses having adequate current-interrupting capacity shall meet the requirements for...

  12. 30 CFR 75.601-2 - Short circuit protection; use of fuses; approval by the Secretary.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Short circuit protection; use of fuses; approval by the Secretary. 75.601-2 Section 75.601-2 Mineral Resources MINE SAFETY AND HEALTH... Trailing Cables § 75.601-2 Short circuit protection; use of fuses; approval by the Secretary. Fuses...

  13. 30 CFR 75.601-3 - Short circuit protection; dual element fuses; current ratings; maximum values.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Short circuit protection; dual element fuses... Trailing Cables § 75.601-3 Short circuit protection; dual element fuses; current ratings; maximum values. Dual element fuses having adequate current-interrupting capacity shall meet the requirements for...

  14. 31 CFR 100.12 - Exchange of fused and mixed coins.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Exchange of fused and mixed coins... OF PAPER CURRENCY AND COIN Exchange of Coin § 100.12 Exchange of fused and mixed coins. (a) Definitions. (1) Fused coins are U.S. coins which are melted to the extent that they are bonded together...

  15. Dynamics of femtosecond laser induced voidlike structures in fused silica

    SciTech Connect

    Mermillod-Blondin, A.; Bonse, J.; Rosenfeld, A.; Hertel, I. V.; Meshcheryakov, Yu. P.; Bulgakova, N. M.; Audouard, E.; Stoian, R.

    2009-01-26

    Focused ultrafast laser irradiation of fused silica usually induces a spatially modulated refractive index variation in the bulk material. Strong energy concentration leads to the localized formation of a lower-density cavitylike depressed structure surrounded by compacted matter. We report on applying time-resolved phase contrast microscopy to investigate the timescale of the void formation. We indicate a temporal behavior consistent with shock wave generation and subsequent rarefaction.

  16. Monolithic Cylindrical Fused Silica Resonators with High Q Factors.

    PubMed

    Pan, Yao; Wang, Dongya; Wang, Yanyan; Liu, Jianping; Wu, Suyong; Qu, Tianliang; Yang, Kaiyong; Luo, Hui

    2016-01-01

    The cylindrical resonator gyroscope (CRG) is a typical Coriolis vibratory gyroscope whose performance is determined by the Q factor and frequency mismatch of the cylindrical resonator. Enhancing the Q factor is crucial for improving the rate sensitivity and noise performance of the CRG. In this paper, for the first time, a monolithic cylindrical fused silica resonator with a Q factor approaching 8 × 10⁵ (ring-down time over 1 min) is reported. The resonator is made of fused silica with low internal friction and high isotropy, with a diameter of 25 mm and a center frequency of 3974.35 Hz. The structure of the resonator is first briefly introduced, and then the experimental non-contact characterization method is presented. In addition, the post-fabrication experimental procedure of Q factor improvement, including chemical and thermal treatment, is demonstrated. The Q factor improvement by both treatments is compared and the primary loss mechanism is analyzed. To the best of our knowledge, the work presented in this paper represents the highest reported Q factor for a cylindrical resonator. The proposed monolithic cylindrical fused silica resonator may enable high performance inertial sensing with standard manufacturing process and simple post-fabrication treatment. PMID:27483263

  17. A hierarachical data structure representation for fusing multisensor information

    SciTech Connect

    Maren, A.J. . Space Inst.); Pap, R.M.; Harston, C.T. )

    1989-01-01

    A major problem with MultiSensor Information Fusion (MSIF) is establishing the level of processing at which information should be fused. Current methodologies, whether based on fusion at the data element, segment/feature, or symbolic levels, are each inadequate for robust MSIF. Data-element fusion has problems with coregistration. Attempts to fuse information using the features of segmented data relies on a Presumed similarity between the segmentation characteristics of each data stream. Symbolic-level fusion requires too much advance processing (including object identification) to be useful. MSIF systems need to operate in real-time, must perform fusion using a variety of sensor types, and should be effective across a wide range of operating conditions or deployment environments. We address this problem through developing a new representation level which facilitates matching and information fusion. The Hierarchical Data Structure (HDS) representation, created using a multilayer, cooperative/competitive neural network, meets this need. The HDS is an intermediate representation between the raw or smoothed data stream and symbolic interpretation of the data. it represents the structural organization of the data. Fused HDSs will incorporate information from multiple sensors. Their knowledge-rich structure aids top-down scene interpretation via both model matching and knowledge-based region interpretation.

  18. A hierarachical data structure representation for fusing multisensor information

    SciTech Connect

    Maren, A.J.; Pap, R.M.; Harston, C.T.

    1989-12-31

    A major problem with MultiSensor Information Fusion (MSIF) is establishing the level of processing at which information should be fused. Current methodologies, whether based on fusion at the data element, segment/feature, or symbolic levels, are each inadequate for robust MSIF. Data-element fusion has problems with coregistration. Attempts to fuse information using the features of segmented data relies on a Presumed similarity between the segmentation characteristics of each data stream. Symbolic-level fusion requires too much advance processing (including object identification) to be useful. MSIF systems need to operate in real-time, must perform fusion using a variety of sensor types, and should be effective across a wide range of operating conditions or deployment environments. We address this problem through developing a new representation level which facilitates matching and information fusion. The Hierarchical Data Structure (HDS) representation, created using a multilayer, cooperative/competitive neural network, meets this need. The HDS is an intermediate representation between the raw or smoothed data stream and symbolic interpretation of the data. it represents the structural organization of the data. Fused HDSs will incorporate information from multiple sensors. Their knowledge-rich structure aids top-down scene interpretation via both model matching and knowledge-based region interpretation.

  19. Monolithic Cylindrical Fused Silica Resonators with High Q Factors

    PubMed Central

    Pan, Yao; Wang, Dongya; Wang, Yanyan; Liu, Jianping; Wu, Suyong; Qu, Tianliang; Yang, Kaiyong; Luo, Hui

    2016-01-01

    The cylindrical resonator gyroscope (CRG) is a typical Coriolis vibratory gyroscope whose performance is determined by the Q factor and frequency mismatch of the cylindrical resonator. Enhancing the Q factor is crucial for improving the rate sensitivity and noise performance of the CRG. In this paper, for the first time, a monolithic cylindrical fused silica resonator with a Q factor approaching 8 × 105 (ring-down time over 1 min) is reported. The resonator is made of fused silica with low internal friction and high isotropy, with a diameter of 25 mm and a center frequency of 3974.35 Hz. The structure of the resonator is first briefly introduced, and then the experimental non-contact characterization method is presented. In addition, the post-fabrication experimental procedure of Q factor improvement, including chemical and thermal treatment, is demonstrated. The Q factor improvement by both treatments is compared and the primary loss mechanism is analyzed. To the best of our knowledge, the work presented in this paper represents the highest reported Q factor for a cylindrical resonator. The proposed monolithic cylindrical fused silica resonator may enable high performance inertial sensing with standard manufacturing process and simple post-fabrication treatment. PMID:27483263

  20. FUSE Observations of the Herbig Be star HD 100546

    NASA Astrophysics Data System (ADS)

    Deleuil, M.; Roberge, A.; Feldman, P. D.; Lecavelier des Etangs, A.; Vidal-Madjar, A.; Bouret, J.-C.; Ferlet, R.; André, M.; Moos, H. W.; Blair, W. P.; FUSE Science Team

    2000-12-01

    The first observation of the Herbig Be star HD100546 in the far UV has been made by the Far Ultraviolet Spectroscopic Explorer (FUSE). The spectra reveal numerous circumstellar absorption lines arising not only from the fine structure levels of refractory species like Fe 2, but also from neutral volatiles: C 1, C 1*, N 1 and N 1*. H2 transitions detected in absorption probe the cold gaseous portion of the circumstellar environment. Strong unexpected emission lines are also observed below 1100 Å, where the stellar continuum flux is very low. In particular, broad C 3 and O 6 emission lines demonstrate the presence of hot, dense, collisionally ionized gas which may be related to an extended chromosphere and/or corona. These features reveal a complex circumstellar environment, with wide range of temperatures and physical conditions. Based on observations obtained for the Guaranteed Time Team by the NASA-CNES-CSA FUSE mission. FUSE is operated for NASA by the John Hopkins University under NASA contract NASS-32985.

  1. FUSE observations of Hot Gas in the Carina Nebula

    NASA Astrophysics Data System (ADS)

    Iping, R. C.; Sonneborn, G.; Jenkins, E. B.; Bowen, D. V.

    2002-06-01

    We present an analysis of interstellar O VI 1031.93 toward several O and WR stars in the Tr 16 cluster, based on high-resolution spectra obtained with the FUSE satellite. The objective of this study is to investigate the distribution of O VI absorption within the cluster. The target stars include CPD-59D2628, CPD-59D2627, CPD-59D2632, HDE 303308, CPD -59 2600, CPD -59 2603, HD093205, HD093204, HD93162, HD093250 and HD 93308 (Eta Car). Two interstellar molecular hydrogen transitions, Lyman 6-0 P(3) 1031.19 and Lyman 6-0 R(4) 1032.35, are located very close to the interstellar O VI feature. These lines have been modelled by analyzing other P(3) and R(4) transitions in the FUSE spectrum. The column densities and distribution of the O VI ion in the Carina Nebulae is determined by using Gaussian profile fitting procedures. These results are compared with FUSE observations of other OB stars in the general vicinity of Carina, but outside the active region. This work has been supported in part by NASA grants NAG5-11137 to Catholic University of America and NASA contract NAS5-32985 to Johns Hopkins University.

  2. FUSE Observations of the Active Interacting Binary RY Persei

    NASA Astrophysics Data System (ADS)

    Peters, G. J.; Polidan, R. S.

    2003-12-01

    RY Per (HD 17034, B4 V + F7 II-III, P=6.86 d) is a massive interacting binary (6.25 M⊙ + 1.60 M⊙, Olson & Plavec 1997, AJ, 113, 425) that displays a variable weak accretion disk that emits in Hα (Barai, et al., preprint). FUSE observations of this system, carried through in 2002 October at phases 0.20, 0.57, and 0.97 and during its total eclipse on 2002 December 8 are presented. The totality data were binned into two phase intervals: 0.0056-0.9976 (after second contact) and 0.0052-0.0089 (just before third contact). Both eclipse observations reveal broad, prominent emission lines of N III (UV1, λ λ 990-992 Å), O VI (UV1, λ λ 1032,1038 Å), N II (UV1, λ λ 1084-1086 Å), Si III (UV5, λ λ 1108,1109,1113 Å), Si IV(UV3, λ λ 1122,1138 Å), and Fe III (UV1, λ λ 1122-32 Å). Emission from C III (UV4, λ 1176 Å) seen during totality in FUSE observations of the Algol binaries V356 Sgr and TT Hya is conspicuously absent. C III (UV1, λ 977 Å) is also absent. This observation combined with the strong presence of N II, III emission suggests that material processed through the CNO cycle in the mass loser is now being transferred to the B star. The FUSE data imply that the emitting plasma is hot ( ˜100,000-300,000 K) and located above/below the orbital plane. The source of this apparent bipolar flow (also seen in V356 Sgr and TT Hya) may be the splash region detected near phase 0.5 in IUE observations of the N V resonance line, but absorption features from this region were not seen in the non-eclipse FUSE observations. A model for the circumstellar material in this system will be presented and the FUSE observations will be compared with those of V356 Sgr and TT Hya. GJP is grateful for support from NASA Grant NAG5-12253.

  3. Influence of S-Oxidation on Cytotoxic Activity of Oxathiole-Fused Chalcones.

    PubMed

    Konieczny, Marek T; Buɬakowska, Anita; Pirska, Danuta; Konieczny, Wojciech; Skladanowski, Andrzej; Sabisz, Michal; Wojciechowski, Marek; Lemke, Krzysztof

    2016-10-01

    Synthesis, in vitro cytotoxic activity, and interaction with tubulin of oxidized, isomeric 1-(5-alkoxybenzo[d][1,3]oxathiol-6-yl)-3-phenylprop-2-en-1-ones and 1-(6-alkoxybenzo[d][1,3]oxathiol-5-yl)-3-phenylprop-2-en-1-ones are described. Most of the compounds demonstrated cytotoxic activity at submicromolar concentrations. It was found that oxidation of sulfur atom of the oxathiole-fused chalcones strongly influenced activity of the parent compounds, and that depending on relative position of the sulfur atom in the molecule, the activity was either increased or diminished. For isomers with sulfur atom para to the chalcone carbonyl group, oxidation led to increase in activity, while for isomers with sulfur atom meta to the carbonyl the activity dropped down. It was demonstrated that the compounds interact with tubulin at the colchicine binding site, and the interaction was evaluated using molecular modeling. It was concluded that the observed profound influence of oxidation of the sulfur atom on cytotoxic activity cannot be solely related to interaction of the compounds with tubulin.

  4. Influence of S-Oxidation on Cytotoxic Activity of Oxathiole-Fused Chalcones.

    PubMed

    Konieczny, Marek T; Buɬakowska, Anita; Pirska, Danuta; Konieczny, Wojciech; Skladanowski, Andrzej; Sabisz, Michal; Wojciechowski, Marek; Lemke, Krzysztof

    2016-10-01

    Synthesis, in vitro cytotoxic activity, and interaction with tubulin of oxidized, isomeric 1-(5-alkoxybenzo[d][1,3]oxathiol-6-yl)-3-phenylprop-2-en-1-ones and 1-(6-alkoxybenzo[d][1,3]oxathiol-5-yl)-3-phenylprop-2-en-1-ones are described. Most of the compounds demonstrated cytotoxic activity at submicromolar concentrations. It was found that oxidation of sulfur atom of the oxathiole-fused chalcones strongly influenced activity of the parent compounds, and that depending on relative position of the sulfur atom in the molecule, the activity was either increased or diminished. For isomers with sulfur atom para to the chalcone carbonyl group, oxidation led to increase in activity, while for isomers with sulfur atom meta to the carbonyl the activity dropped down. It was demonstrated that the compounds interact with tubulin at the colchicine binding site, and the interaction was evaluated using molecular modeling. It was concluded that the observed profound influence of oxidation of the sulfur atom on cytotoxic activity cannot be solely related to interaction of the compounds with tubulin. PMID:27198732

  5. Mitigation of Laser Damage Growth in Fused Silica with a Galvanometer Scanned CO2 Laser

    SciTech Connect

    Bass, I L; Guss, G M; Hackel, R P

    2005-10-28

    At the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL), mitigation of laser surface damage growth on fused silica using single and multiple CO{sub 2} laser pulses has been consistently successful for damage sites whose lateral dimensions are less than 100 {micro}m, but has not been for larger sites. Cracks would often radiate outward from the damage when a CO{sub 2} pulse was applied to the larger sites. An investigation was conducted to mitigate large surface damage sites using galvanometer scanning of a tightly focused CO{sub 2} laser spot over an area encompassing the laser damage. It was thought that by initially scanning the CO{sub 2} spot outside the damage site, radiating crack propagation would be inhibited. Scan patterns were typically inward moving spirals starting at radii somewhat larger than that of the damage site. The duration of the mitigation spiral pattern was {approx}110 ms during which a total of {approx}1.3 J of energy was delivered to the sample. The CO{sub 2} laser spot had a 1/e{sup 2}-diameter of {approx}200 {micro}m. Thus, there was general heating of a large area around the damage site while rapid evaporation occurred locally at the laser spot position in the spiral. A 30 to 40 {micro}m deep crater was typically generated by this spiral with a diameter of {approx}600 {micro}m. The spiral would be repeated until there was no evidence of the original damage in microscope images. Using this technique, damage sites as large as 300 mm in size did not display new damage after mitigation when exposed to fluences exceeding 22 J/cm{sup 2} at 355 nm, 7.5 ns. It was found necessary to use a vacuum nozzle during the mitigation process to reduce the amount of re-deposited fused silica. In addition, curing spiral patterns at lower laser powers were used to presumably ''re-melt'' any re-deposited fused silica. A compact, shearing interferometer microscope was developed to permit in situ measurement of the depth of

  6. Ambiphilic properties of SF5CF2CF2Br derived perfluorinated radical in addition reactions across carbon-carbon double bonds.

    PubMed

    Dudziński, Piotr; Matsnev, Andrej V; Thrasher, Joseph S; Haufe, Günter

    2015-03-01

    The extraordinary properties of the pentafluorosulfanyl (SF5) group attract attention of organic chemists. While numerous SF5-substituted compounds have been synthesized, the direct introduction of SF5(CF2)n moieties has remained almost unexplored. Our investigations revealed the ambiphilic character of the SF5CF2CF2 radical. Addition reactions to electron-rich or electron-deficient alkenes profit either from its electrophilic or nucleophilic properties. Thus, the readily available SF5CF2CF2Br proved to be a promising and versatile building block for the introduction of this perfluorinated moiety.

  7. Quantitative characterization of the interactions among c-myc transcriptional regulators FUSE, FBP, and FIR.

    PubMed

    Hsiao, Hsin-Hao; Nath, Abhinav; Lin, Chi-Yen; Folta-Stogniew, Ewa J; Rhoades, Elizabeth; Braddock, Demetrios T

    2010-06-01

    Human c-myc is critical for cell homeostasis and growth but is a potent oncogenic factor if improperly regulated. The c-myc far-upstream element (FUSE) melts into single-stranded DNA upon active transcription, and the noncoding strand FUSE recruits an activator [the FUSE-binding protein (FBP)] and a repressor [the FBP-interacting repressor (FIR)] to fine-tune c-myc transcription in a real-time manner. Despite detailed biological experiments describing this unique mode of transcriptional regulation, quantitative measurements of the physical constants regulating the protein-DNA interactions remain lacking. Here, we first demonstrate that the two FUSE strands adopt different conformations upon melting, with the noncoding strand DNA in an extended, linear form. FBP binds to the linear noncoding FUSE with a dissociation constant in the nanomolar range. FIR binds to FUSE more weakly, having its modest dissociation constants in the low micromolar range. FIR is monomeric under near-physiological conditions but upon binding of FUSE dimerizes into a 2:1 FIR(2)-FUSE complex mediated by the RRMs. In the tripartite interaction, our analysis suggests a stepwise addition of FIR onto an activating FBP-FUSE complex to form a quaternary FIR(2)-FBP-FUSE inhibitory complex. Our quantitative characterization enhances understanding of DNA strand preference and the mechanism of the stepwise complex formation in the FUSE-FBP-FIR regulatory system.

  8. Preparation, characterization of LiNi{sub 1/3}Mn{sub 1/3}Co{sub 1/3}O{sub 2} film cathode.

    SciTech Connect

    Kang, S. H.; Abraham, D. P.; Chemical Engineering

    2006-01-01

    Positive electrodes based on the LiNi{sub 1/3}Mn{sub 1/3}Co{sub 1/3}O{sub 2} material are being evaluated in high-power lithium-ion cells for hybrid-electric vehicle applications. To determine performance degradation mechanisms that are associated with the active material, we prepared carbon- and binder-free LiNi{sub 1/3}Mn{sub 1/3}Co{sub 1/3}O{sub 2} film cathode on a Pt substrate using a sol-gel spin coating technique. The material was characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Initial data from cyclic voltammetry, galvanostatic cycling, and electrochemical impedance spectroscopy measurements conducted on the electrodes are reported.

  9. Distributions and bioconcentration characteristics of perfluorinated compounds in environmental samples collected from the west coast of Korea.

    PubMed

    Naile, Jonathan E; Khim, Jong Seong; Hong, Seongjin; Park, Jinsoon; Kwon, Bong-Oh; Ryu, Jong Seong; Hwang, Jin Hwan; Jones, Paul D; Giesy, John P

    2013-01-01

    As part of an ongoing study of the status and trends of contaminants in the Yellow Sea, during May of 2009, the concentrations of perfluorinated compounds (PFCs) were determined in water (n=15), sediment (n=12), soil (n=13), and biota (n=74) from estuarine and coastal areas along the west coast of Korea. Of the 12PFCs monitored, PFOS and PFOA were the most frequently detected compounds in water. Greater concentrations of PFCs were found in waters from the inner regions of sea dikes in three artificial lakes, Shihwa, Asan, and Sapgyo, than outer regions. Concentrations were also comparable in two estuarine areas, which indicated that most PFCs in coastal areas originated from industrial and local regions and river water flowing through estuaries. Concentrations of PFCs in soils and sediments were generally less than limits of quantification and were generally less than those measured in biota. Compound-specific bioaccumulation of PFBS and PFOS had the greatest BCF values in crab, while in fish it was PFOS and PFDA, and in gastropods and bivalves it was PFHxS. Distributions of BCFs for PFOS in body-parts of crab showed the greatest values in soft tissues followed by shells and then legs. Distribution among tissues and organs of fishes was more variable than those observed for crab. When compared to a similar study conducted by our group in 2008, concentrations of PFCs in water samples were significantly less in 2009. However, there was little change in bioconcentration from sediments into benthic organisms. Finally, we conducted the assessment of potential adverse effects for PFCs on aquatic life by use of current and previous reported data.

  10. Molecular impacts of perfluorinated chemicals (PFASs) in the liver and testis of male largemouth bass (Micropterus salmoides) in Minnesota Lakes.

    PubMed

    Collí-Dulá, Reyna Cristina; Martyniuk, Christopher J; Streets, Summer; Denslow, Nancy D; Lehr, Randy

    2016-09-01

    Perfluorinated chemicals (PFASs) stem from a wide range of sources and have been detected in aquatic ecosystems worldwide, including the upper Midwest and the state of Minnesota in the USA. This study investigated whether fish with high body burden levels of PFASs in the Twin Cities Metro Areas showed any evidence of adverse effects at the level of the transcriptome. We hypothesized that fish with higher body burden levels of PFASs would exhibit molecular responses in the liver and testis that were suggestive of oxidative and general stress, as well as impaired reproduction. Concentrations of PFASs in largemouth bass varied significantly across the sampled lakes, with the lowest concentrations of PFASs found in fish from Steiger and Upper Prior Lakes and the highest concentrations found in fish from Calhoun and Twin Lakes. Largemouth bass with high PFAS concentrations exhibited changes in the expression of genes related to lipid metabolism, energy production, RNA processing, protein production/degradation and contaminant detoxification, all of which are consistent with biomarker responses observed in other studies with PFASs. However, given the wide range of genes that were differentially expressed across the lakes and the variability observed in the mechanisms through which biological processes were affected, it is unlikely that PFASs are the only stressors affecting largemouth bass in the Twin Cities Metro Areas lakes. Indeed, Twin Lake is affected by the Joslyn superfund site which contains polycyclic aromatic hydrocarbons, pentachlorophenol, polychlorinated biphenyls, and dioxins. These compounds are also expected to drive the transcriptomics responses observed, but to what degree is difficult to ascertain at this time. PMID:26907229

  11. Molecular impacts of perfluorinated chemicals (PFASs) in the liver and testis of male largemouth bass (Micropterus salmoides) in Minnesota Lakes.

    PubMed

    Collí-Dulá, Reyna Cristina; Martyniuk, Christopher J; Streets, Summer; Denslow, Nancy D; Lehr, Randy

    2016-09-01

    Perfluorinated chemicals (PFASs) stem from a wide range of sources and have been detected in aquatic ecosystems worldwide, including the upper Midwest and the state of Minnesota in the USA. This study investigated whether fish with high body burden levels of PFASs in the Twin Cities Metro Areas showed any evidence of adverse effects at the level of the transcriptome. We hypothesized that fish with higher body burden levels of PFASs would exhibit molecular responses in the liver and testis that were suggestive of oxidative and general stress, as well as impaired reproduction. Concentrations of PFASs in largemouth bass varied significantly across the sampled lakes, with the lowest concentrations of PFASs found in fish from Steiger and Upper Prior Lakes and the highest concentrations found in fish from Calhoun and Twin Lakes. Largemouth bass with high PFAS concentrations exhibited changes in the expression of genes related to lipid metabolism, energy production, RNA processing, protein production/degradation and contaminant detoxification, all of which are consistent with biomarker responses observed in other studies with PFASs. However, given the wide range of genes that were differentially expressed across the lakes and the variability observed in the mechanisms through which biological processes were affected, it is unlikely that PFASs are the only stressors affecting largemouth bass in the Twin Cities Metro Areas lakes. Indeed, Twin Lake is affected by the Joslyn superfund site which contains polycyclic aromatic hydrocarbons, pentachlorophenol, polychlorinated biphenyls, and dioxins. These compounds are also expected to drive the transcriptomics responses observed, but to what degree is difficult to ascertain at this time.

  12. Perfluorinated Compounds and Polybrominated Diphenyl Ethers in Great Blue Heron Eggs from Three Colonies on the Mississippi River, Minnesota

    USGS Publications Warehouse

    Custer, T.W.; Kannan, K.; Tao, L.; Yun, S.-H.; Trowbridge, A.

    2010-01-01

    Archived Great Blue Heron (Ardea herodias) eggs (N = 16) collected in 1993 from three colonies on the Mississippi River in Minnesota were analyzed in 2007 for perfluorinated compounds (PFCs) and polybrominated diphenyl ethers (PBDEs). One of the three colonies, Pig's Eye, was located near a presumed source of PFCs. Based on a multivariate analysis, the pattern of nine PFC concentrations differed significantly between Pig's Eye and the upriver (P = 0.002) and downriver (P = 0.02) colonies; but not between the upriver and downriver colonies (P = 0.25). Mean concentrations of perfluorooctane sulfonate (PFOS), a major PFC compound, were significantly higher at the Pig's Eye colony (geometric mean = 940 ng/g wet weight) than at upriver (60 ng/g wet weight) and downriver (131 ng/g wet weight) colonies. Perfluorooctane sulfonate concentrations from the Pig's Eye colony are among the highest reported in bird eggs. Concentrations of PFOS in Great Blue Heron eggs from Pig's Eye were well below the toxicity thresholds estimated for Bobwhite Quail (Colinus virginianus) and Mallards (Anas platyrhynchos), but within the toxicity threshold estimated for White Leghorn Chickens (Gallus domesticus). The pattern of six PBDE congener concentrations did not differ among the three colonies (P = 0.08). Total PBDE concentrations, however, were significantly greater (P = 0.03) at Pig's Eye (geometric mean = 142 ng/g wet weight) than the upriver colony (13 ng/g wet weight). Polybrominated diphenyl ether concentrations in two of six Great Blue Heron eggs from the Pig's Eye colony were within levels associated with altered reproductive behavior in American Kestrels (Falco sparverius).

  13. Fragmentation and reactivity in collisions of protonated diglycine with chemically modified perfluorinated alkylthiolate-self-assembled monolayer surfaces

    SciTech Connect

    Barnes, George L.; Yang Li; Hase, William L.; Young, Kelsey

    2011-03-07

    Direct dynamics simulations are reported for quantum mechanical (QM)/molecular mechanical (MM) trajectories of N-protonated diglycine (gly{sub 2}-H{sup +}) colliding with chemically modified perfluorinated octanethiolate self-assembled monolayer (SAM) surfaces. The RM1 semiempirical theory is used for the QM component of the trajectories. RM1 activation and reaction energies were compared with those determined from higher-level ab initio theories. Two chemical modifications are considered in which a head group (-COCl or -CHO) is substituted on the terminal carbon of a single chain of the SAM. These surfaces are designated as the COCl-SAM and CHO-SAM, respectively. Fragmentation, peptide reaction with the SAM, and covalent linkage of the peptide or its fragments with the SAM surface are observed. Peptide fragmentation via concerted CH{sub 2}-CO bond breakage is the dominant pathway for both surfaces. HCl formation is the dominant species produced by reaction with the COCl-SAM, while for the CHO-SAM a concerted H-atom transfer from the CHO-SAM to the peptide combined with either a H-atom or radical transfer from the peptide to the surface to form singlet reaction products is the dominant pathway. A strong collision energy dependence is found for the probability of peptide fragmentation, its reactivity, and linkage with the SAM. Surface deposition, i.e., covalent linkage between the surface and the peptide, is compared to recent experimental observations of such bonding by Laskin and co-workers [Phys. Chem. Chem. Phys. 10, 1512 (2008)]. Qualitative differences in reactivity are seen between the COCl-SAM and CHO-SAM showing that chemical identity is important for surface reactivity. The probability of reactive surface deposition, which is most closely analogous to experimental observables, peaks at a value of around 20% for a collision energy of 50 eV.

  14. Perfluorinated alkyl substances in water, sediment, plankton and fish from Korean rivers and lakes: a nationwide survey.

    PubMed

    Lam, Nguyen-Hoang; Cho, Chon-Rae; Lee, Jung-Sick; Soh, Ho-Young; Lee, Byoung-Cheun; Lee, Jae-An; Tatarozako, Norihisa; Sasaki, Kazuaki; Saito, Norimitsu; Iwabuchi, Katsumi; Kannan, Kurunthachalam; Cho, Hyeon-Seo

    2014-09-01

    Water, sediment, plankton, and blood and liver tissues of crucian carp (Carassius auratus) and mandarin fish (Siniperca scherzeri) were collected from six major rivers and lakes in South Korea (including Namhan River, Bukhan River, Nakdong River, Nam River, Yeongsan River and Sangsa Lake) and analyzed for perfluorinated alkyl substances (PFASs). Perfluorooctane sulfonate (PFOS) was consistently detected at the greatest concentrations in all media surveyed with the maximum concentration in water of 15 ng L(-1) and in biota of 234 ng mL(-1) (fish blood). A general ascending order of PFAS concentration of water0.80, p<0.001) were observed between PFOS concentration in blood and liver tissues of both crucian carp and mandarin fish. This result suggests that blood can be used for nonlethal monitoring of PFOS in fish. Overall, the rank order of mean bioconcentration factors (BCFs) of PFOS in biota was; phytoplankton (196 L/kg)

  15. Oxidative toxicity of perfluorinated chemicals in green mussel and bioaccumulation factor dependent quantitative structure-activity relationship.

    PubMed

    Liu, Changhui; Chang, Victor W C; Gin, Karina Y H

    2014-10-01

    Concerns regarding perfluorinated chemicals (PFCs) have risen in recent years because of their ubiquitous presence and high persistency. However, data on the environmental impacts of PFCs on marine organisms are very limited. Oxidative toxicity has been suggested to be one of the major toxic pathways for PFCs to induce adverse effects on organisms. To investigate PFC-induced oxidative stress and oxidative toxicity, a series of antioxidant enzyme activities and oxidative damage biomarkers were examined to assess the adverse effects of the following 4 commonly detected compounds: perfluoro-octanesulfonate, perfluoro-ocanoic acid, perfluorononanoic acid, and perfluorodecanoic acid, on green mussel (Perna viridis). Quantitative structure-activity relationship (QSAR) models were also established. The results showed that all the tested PFCs are able to induce antioxidant response and oxidative damage on green mussels in a dose-dependent manner. At low exposure levels (0 µg/L-100 µg/L), activation of antioxidant enzymes (catalase [CAT] and superoxide dismutase [SOD]) was observed, which is an adaptive response to the excessive reactive oxygen species induced by PFCs, while at high exposure levels (100 µg/L-10 000 µg/L), PFCs were found to inhibit some enzyme activity (glutathione S-transferase and SOD) where the organism's ability to respond in an adaptive manner was compromised. The oxidative stress under high PFC exposure concentration also led to lipid and DNA damage. PFC-induced oxidative toxicity was found to be correlated with the bioaccumulation potential of PFCs. Based on this relationship, QSAR models were established using the bioaccumulation factor (BAF) as the molecular descriptor for the first time. Compared with previous octanol-water partition coefficient-dependent QSAR models, the BAF-dependent QSAR model is more suitable for the impact assessment of PFCs and thus provides a more accurate description of the toxic behavior of these compounds.

  16. Serum Perfluorinated Compound Concentration and Attention Deficit/Hyperactivity Disorder in Children 5–18 Years of Age

    PubMed Central

    Savitz, David A.

    2011-01-01

    Background: Perfluorinated compounds (PFCs) are persistent environmental pollutants. Toxicology studies demonstrate the potential for perfluorooctanoic acid (PFOA) and other PFCs to affect human growth and development. Attention deficit/hyperactivity disorder (ADHD) is a developmental disorder with suspected environmental and genetic etiology. Objectives: We examined the cross-sectional association between serum PFC concentration and parent or self-report of doctor-diagnosed ADHD with and without current ADHD medication. Methods: We used data from the C8 Health Project, a 2005–2006 survey in a Mid-Ohio Valley community highly exposed to PFOA through contaminated drinking water, to study non-Hispanic white children 5–18 years of age. Logistic regression models were adjusted for age and sex. Results: Of the 10,546 eligible children, 12.4% reported ADHD and 5.1% reported ADHD plus ADHD medication use. We observed an inverted J-shaped association between PFOA and ADHD, with a small increase in prevalence for the second quartile of exposure compared with the lowest, and a decrease for the highest versus lowest quartile. The prevalence of ADHD plus medication increased with perfluorohexane sulfonate (PFHxS) levels, with an adjusted odds ratio of 1.59 (95% confidence interval, 1.21–2.08) comparing the highest quartile of exposure to the lowest. We observed a modest association between perfluorooctane sulfonate and ADHD with medication. Conclusions: The most notable finding for PFOA and ADHD, a reduction in prevalence at the highest exposure level, is unlikely to be causal, perhaps reflecting a spurious finding related to the geographic determination of PFOA exposure in this population or to unmeasured behavioral or physiologic correlates of exposure and outcome. Possible positive associations between other PFCs and ADHD, particularly PFHxS, warrant continued investigation. PMID:21665566

  17. Water quality criteria for hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX).

    PubMed

    Etnier, E L

    1989-04-01

    The occurrence of the munitions compound hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in groundwater surrounding Army ammunition plants may result in contamination of local drinking water supplies. RDX exerts its primary toxic effect in humans on the central nervous system, but also involves gastrointestinal and renal effects. Symptomatic effects following acute exposure include hyperirritability, nausea, vomiting, generalized epileptiform seizures, and prolonged postictal confusion and amnesia. Health effects data were analyzed for RDX, and although no controlled human studies exist concerning the acute or chronic toxic effects of exposure to RDX, sufficient animal toxicity data are available to derive an ambient water quality criterion for the protection of human health. This paper summarizes the available literature on metabolism of RDX and human and animal toxicity. Based on noncarcinogenic mammalian toxicity data, and following the methodologies of the U.S. Environmental Protection Agency, an ambient water quality criterion for the protection of human health of 103 micrograms/liter is proposed for ingestion of drinking water and aquatic foodstuffs. A criterion of 105 micrograms/liter is proposed for ingestion of drinking water alone.

  18. Water quality criteria for hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)

    SciTech Connect

    Etnier, E.L.

    1989-04-01

    The occurrence of the munitions compound hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in groundwater surrounding Army ammunition plants may result in contamination of local drinking water supplies. RDX exerts its primary toxic effect in humans on the central nervous system, but also involves gastrointestinal and renal effects. Symptomatic effects following acute exposure include hyperirritability, nausea, vomiting, generalized epileptiform seizures, and prolonged postictal confusion and amnesia. Health effects data were analyzed for RDX, and although no controlled human studies exist concerning the acute or chronic toxic effects of exposure to RDX, sufficient animal toxicity data are available to derive an ambient water quality criterion for the protection of human health. This paper summarizes the available literature on metabolism of RDX and human and animal toxicity. Based on noncarcinogenic mammalian toxicity data, and following the methodologies of the U.S. Environmental Protection Agency, an ambient water quality criterion for the protection of human health of 103 micrograms/liter is proposed for ingestion of drinking water and aquatic foodstuffs. A criterion of 105 micrograms/liter is proposed for ingestion of drinking water alone.54 references.

  19. Tree classification with fused mobile laser scanning and hyperspectral data.

    PubMed

    Puttonen, Eetu; Jaakkola, Anttoni; Litkey, Paula; Hyyppä, Juha

    2011-01-01

    Mobile Laser Scanning data were collected simultaneously with hyperspectral data using the Finnish Geodetic Institute Sensei system. The data were tested for tree species classification. The test area was an urban garden in the City of Espoo, Finland. Point clouds representing 168 individual tree specimens of 23 tree species were determined manually. The classification of the trees was done using first only the spatial data from point clouds, then with only the spectral data obtained with a spectrometer, and finally with the combined spatial and hyperspectral data from both sensors. Two classification tests were performed: the separation of coniferous and deciduous trees, and the identification of individual tree species. All determined tree specimens were used in distinguishing coniferous and deciduous trees. A subset of 133 trees and 10 tree species was used in the tree species classification. The best classification results for the fused data were 95.8% for the separation of the coniferous and deciduous classes. The best overall tree species classification succeeded with 83.5% accuracy for the best tested fused data feature combination. The respective results for paired structural features derived from the laser point cloud were 90.5% for the separation of the coniferous and deciduous classes and 65.4% for the species classification. Classification accuracies with paired hyperspectral reflectance value data were 90.5% for the separation of coniferous and deciduous classes and 62.4% for different species. The results are among the first of their kind and they show that mobile collected fused data outperformed single-sensor data in both classification tests and by a significant margin.

  20. D/H Toward BD+28 4211: First FUSE Results

    NASA Technical Reports Server (NTRS)

    Sonneborne, George; Andre, M.; Oliveira, C.; Friedman, S. D.; Howk, J. C.; Kruk, J. W.; Moos, H. W.; Oegerle, W. R.; Sembach, K. R.; Chayer, P.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    The atomic deuterium-to-hydrogen abundance ratio has been evaluated for the sight line toward the hot O subdwarf BD+28(sup circ) 4211. High signal-to-noise ratio (S/N is approx. 100) observations covering the wavelength range 905 to 1187 angstroms at a wavelength resolving power of lambda/Delta/lambda at approx. 20,000 were obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. BD+28(sup circ) 4211 is approx. 00 pc away with a total H I column density of approx. 10(exp 19)/sq cm, much higher than is typically found in the local interstellar medium (ISM). The deuterium column density was measured by analyzing several D I Lyman series transitions (Lyman delta, C, epsilon, eta, theta, iota with curve of growth and profile fitting techniques, after determining which lines were free of interference from other interstellar species and narrow stellar features. The neutral hydrogen column density was measured by an analysis of the Lyman-alpha profile using HST/Space Telescope Imaging Spectrograph (STIS) and Goddard High Resolution Spectrograph (GHRS) spectra. The stellar spectrum of BD+28(sup circ) 4211 was modelled to assist in determining the sensitivity of H I (Ly-alpha) and D I to the continuum placement and to identify stellar transitions. The D I and H I column densities, their uncertainties, and potential sources of systematic error will be presented. This work is based on data obtained for the FUSE Guaranteed Time Team by the NASA-CNES-CSA FUSE mission operated by the Johns Hopkins University. Financial support to U. S. participants has been provided in part by NASA contract NAS5-32985.

  1. Cepheid Masses: FUSE Observations of S Mus B

    NASA Astrophysics Data System (ADS)

    Evans, N. R.; Massa, D.; Fullerton, A. W.; Sonneborn, G.; Iping, R.

    2004-05-01

    Measurement of Cepheid masses has been a goal both in order to understand these primary distance indicators and also as a benchmark for stellar evolution calculations of high mass stars. The approach is to use ultraviolet spectroscopy (IUE, HST GHRS, and HST STIS) to measure the orbital velocity amplitude of the hot companion of a binary Cepheid. This amplitude plus the Cepheid orbital velocity amplitude from the ground provides the mass ratio between the Cepheid and the companion. The mass of the companion is inferred from an ultraviolet spectral type and hence the mass of the Cepheid is determined. S Mus B is the hottest Cepheid companion known. As a benefit, the large ultraviolet flux made it the only Cepheid companion for which the velocity amplitude could be measured with the echelle mode of the HST GHRS. Unfortunately, the high temperature of S Mus B is difficult to constrain at wavelengths longer than 1200 A because of the degeneracy between temperature and reddening. Thus the companion has the most accurate velocity amplitude of any Cepheid binary, but a relatively inaccurate mass. We have now obtained a FUSE spectrum, and have identified two regions which are temperature sensitive but relatively unaffected by H2 absorption (940 A and Ly Beta wings). By comparing S Mus B with other FUSE spectra, we have determined a temperature of 17,000 K. The resultant Cepheid mass is 6.0 +/- 0.4 solar masses. Financial assistance was provided by Chandra X-ray Center NASA Contract NAS8-39073 for NRE and FUSE grant NAG5-11946.

  2. Evaluation of algorithms for fusing infrared and synthetic imagery

    NASA Astrophysics Data System (ADS)

    Simard, Philippe; Link, Norah K.; Kruk, Ronald V.

    2000-06-01

    Algorithms for image fusion were evaluated as part of the development of an airborne Enhanced/Synthetic Vision System (ESVS) for helicopter Search and Rescue operations. The ESVS will be displayed on a high- resolution, wide field-of-view helmet-mounted display (HMD). The HMD full field-of-view (FOV) will consist of a synthetic image to support navigation and situational awareness, and an infrared image inset will be fused into the center of the FOV to provide real-world feedback and support flight operations at low altitudes. Three fusion algorithms were selected for evaluation against the ESVS requirements. In particular, algorithms were modified and tested against the unique problem of presenting a useful fusion of varying quality. A pixel averaging algorithm was selected as the simplest way to fuse two difference sources of imagery. Two other algorithms, originally developed for real- time fusion of low-light visible images with infrared images, (one at the TNO Human Factors Institute and the other at the MIT Lincoln Laboratory) were adapted and implemented. To evaluate the algorithms' performance, artificially generated infrared images were fused with synthetic images and viewed in a sequence corresponding to a search and rescue scenario for a descent to hover. Application of all three fusion algorithms improved the raw infrared image, but the MIT-based algorithm generated some undesirable effects such as contrast reversals. This algorithm was also computationally intensive and relatively difficult to tun. The pixel averaging problem was simplest in terms of per-pixel operations and provided good results. The TNO-based algorithm was superior in that while it was slightly more complex than pixel averaging, it demonstrated similar results, was more flexible, and had the advantage of predictably preserving certain synthetic features which could be used to support obstacle detection.

  3. Synthesis of steroidal derivatives containing substituted, fused and spiro pyrazolines.

    PubMed

    Romero-López, Anabel; Montiel-Smith, Sara; Meza-Reyes, Socorro; Merino-Montiel, Penélope; Vega-Baez, José Luis

    2014-09-01

    An efficient and facile synthesis of fused, substituted and spiro pyrazoline steroid derivatives through a cycloaddition reaction of different α,β-unsaturated ketones with hydrazine acetate in acetic acid is reported. Depending on the starting material, the ring closure reaction provided a mixture of two steroidal pyrazoline epimers that were separated and studied by NMR techniques. In one case it was possible to isolate and characterize the hydrazone derivative as the reaction intermediate, which confirms the mechanism proposed in the literature [11,25,26].

  4. Fused silica diaphragm module for high temperature pressure transducers

    NASA Technical Reports Server (NTRS)

    Berthold, III, John W. (Inventor)

    1986-01-01

    A high temperature pressure transducer and sensing apparatus to determine the deflection of the transducer diaphragm is disclosed. The pressure transducer utilizes a fused silica diaphragm (12) which is illuminated at selected locations by a coherent laser source (52) via optical fibers (38, 46). The light reflected by the diaphragm (12) forms interference fringe patterns which are focused by gradient index rod lenses (36) on the ends of optical fibers (40, 48) for transmission to a fringe counting circuit (54). By digital techniques, the fringe count is converted into a determination of diaphragm deflection.

  5. Fused double supernumerary premolars of the mandible: a rare case.

    PubMed

    Dawasaz, Ali Azhar; Sadatullah, Syed; Bokhari, Syed Kamran

    2012-01-01

    The incidence of nonsyndromic supernumerary premolars is rare. Supernumerary premolars are likely to undergo pathological changes. The most commonly encountered complications with these teeth are dentigerous cyst and root resorption of the adjacent tooth. This paper is about impacted double fused supernumerary premolars in the right mandiblular body associated with an impacted first premolar in a 17-year-old male. Under local anesthesia, the supernumerary premolars and the impacted permanent first premolar were surgically removed. Early diagnosis followed by an appropriate treatment at the right time will result in favorable prognosis in such cases. PMID:23346423

  6. Bioactive fused heterocycles: Nucleoside analogs with an additional ring.

    PubMed

    Jahnz-Wechmann, Zofia; Framski, Grzegorz; Januszczyk, Piotr; Boryski, Jerzy

    2015-06-01

    The following mini-review summarizes the basic literature data regarding synthesis, biological activity, structure-activity relationship, and discussion of the mechanisms of action of two major classes of nucleoside analogs with fused heterocyclic rings: (i) the ethenonucleosides and their related derivatives of the 5,9-dihydro-3-glycosyl-6-alkyl-9-oxo-5H-imidazo[1,2-a]purine type; (ii) the bicyclic nucleosides of 6-alkyl-2,3-dihydrofurano[2,3-d]-pyrimidin-2(3H)-one and 6-alkyl-2,3-dihydropyrrolo[2,3-d]-pyrimidin-2(3H,7H)-one. PMID:25576500

  7. Processing of fused silicide coatings for carbon-based materials

    NASA Technical Reports Server (NTRS)

    Smialek, J. L.

    1982-01-01

    The processing and oxidation resistance of fused Al-Si and Ni-Si slurry coatings on ATJ graphite was studied. Ni-Si coatings in the 70 to 90 percent Si range were successfully processed to melt, wet, and bond to the graphite. The molten coatings also infiltrated the porosity in graphite and reacted with it to form SiC in the coating. Cyclic oxidation at 1200 C showed that these coatings were not totally protective because of local attack of the substrate, due to the extreme thinness of the coatings in combination with coating cracks.

  8. Processing of fused silicide coatings for carbon-based materials

    NASA Technical Reports Server (NTRS)

    Smialek, J. L.

    1983-01-01

    The processing and oxidation resistance of fused Al-Si and Ni-Si slurry coatings on ATJ graphite was studied. Ni-Si coatings in the 70 to 90 percent Si range were successfully processed to melt, wet, and bond to the graphite. The molten coatings also infiltrated the porosity in graphite and reacted with it to form SiC in the coating. Cyclic oxidation at 1200 C showed that these coatings were not totally protective because of local attack of the substrate, due to the extreme thinness of the coatings in combination with coating cracks. Previously announced in STAR as N83-27019

  9. High-efficiency transmission gratings fabricated in bulk fused silica

    SciTech Connect

    Nguyen, H.T.; Shore, B.W.; Britten, J.A.; Bryan, S.J.; Falabella, S.; Boyd, R.D.; Perry, M.D.

    1996-03-01

    The authors present the design and performance of high-efficiency transmission gratings fabricated in bulk fused silica for use in ultraviolet high-power laser systems. The gratings exhibit a diffraction efficiency exceeding 95% in the m = {minus}1 order and damage threshold greater than 13 J/cm{sup 2} for 1 nsec pulses at 351 nm. Model calculations and experimental measurements are in good agreement. They describe the design and fabrication of these gratings based on the transfer ion etching of photoresist patterns produced by interference lithography.

  10. Testing of Gyroless Estimation Algorithms for the Fuse Spacecraft

    NASA Technical Reports Server (NTRS)

    Harman, R.; Thienel, J.; Oshman, Yaakov

    2004-01-01

    This paper documents the testing and development of magnetometer-based gyroless attitude and rate estimation algorithms for the Far Ultraviolet Spectroscopic Explorer (FUSE). The results of two approaches are presented, one relies on a kinematic model for propagation, a method used in aircraft tracking, and the other is a pseudolinear Kalman filter that utilizes Euler's equations in the propagation of the estimated rate. Both algorithms are tested using flight data collected over a few months after the failure of two of the reaction wheels. The question of closed-loop stability is addressed. The ability of the controller to meet the science slew requirements, without the gyros, is analyzed.

  11. FUSE Analysis of the Cyg OB1 Superbubble

    NASA Technical Reports Server (NTRS)

    Nichols, J.; Mendygral, P.

    1996-01-01

    FUSE observations of four stars in the line of sight to the Cyg OB1 IR-detected superbubble have been analyzed for high-velocity features in the O VI interstellar lines, which might be attributed to the shock structure of the superbubble. Multiple components were detected in the spectra of all four stars, with a velocity range of -85 kilometers per second to +29 kilometers per second. As many as four separate velocity components were identified in each spectrum, implying multiple shock structures in the superbubble. Derived column densities of the O VI components indicate shock velocities of 160-190 kilometers per second according to steady state shock theory.

  12. Shocks in Dense Clouds in the Vela Supernova Remnant: FUSE

    NASA Technical Reports Server (NTRS)

    Nichols, Joy; Sonneborn, George (Technical Monitor)

    2002-01-01

    We have obtained 8 LWRS FUSE spectra to study a recently identified interaction of the Vela supernova remnant with a dense cloud region along its western edge. The goal is to quantify the temperature, ionization, density, and abundance characteristics associated with this shock/dense cloud interface by means of UV absorption line studies. Our detection of high-velocity absorption line C I at +90 to +130 km/s with IUE toward a narrow region interior to the Vela SNR strongly suggests the Vela supernova remnant is interacting with a dense ISM or molecular cloud. The shock/dense cloud interface is suggested by (1) the rarity of detection of high-velocity C I seen in IUE spectra, (2) its very limited spatial distribution in the remnant, and (3) a marked decrease in X-ray emission in the region immediately west of the position of these stars where one also finds a 100 micron emission ridge in IRAS images. We have investigated the shock physics and general properties of this interaction region through a focussed UV absorption line study using FUSE spectra. We have FUSE data on OVI absorption lines observed toward 8 stars behind the Vela supernova remnant (SNR). We compare the OVI observations with IUE observations of CIV absorption toward the same stars. Most of the stars, which are all B stars, have complex continua making the extraction of absorption lines difficult. Three of the stars, HD 72088, HD 72089 and HD 72350, however, are rapid rotators (v sin i less than 100 km/s) making the derivation of absorption column densities much easier. We have measured OVI and CIV column densities for the "main component" (i.e. the low velocity component) for these stars. In addition, by removing the H2 line at 1032.35A (121.6 km/s relative to OVI), we find high velocity components of OVI at approximately 150 km/s that we attribute to the shock in the Vela SNR. The column density ratios and magnitudes are compared to both steady shock models and results of hydrodynamical SNR

  13. Mechanical loss of laser-welded fused silica fibers

    NASA Astrophysics Data System (ADS)

    Harry, Gregory; Corbitt, Thomas; Freytsis, Marat; Ottaway, David; Mavalvala, Nergis; Penn, Steve

    2006-02-01

    The mechanical quality factor of a carbon dioxide laser-welded fiber was measured and compared to flame-welded fibers to determine the suitability of laser welding for attaching suspension fibers to test masses in precision experiments. The loss in the fiber was found to be limited primarily by thermoelastic damping and surface loss, rather than loss from the weld. This technique is attractive for the attachment of fused silica suspensions where low thermal noise and precision location of the weld are considered.

  14. Temperature dependence of VUV transmission of synthetic fused silica

    NASA Astrophysics Data System (ADS)

    Franke, St.; Lange, H.; Schoepp, H.; Witzke, H.-D.

    2006-07-01

    The temperature dependence of the VUV transmission of synthetic fused silica is of interest for commercial applications as well as for fundamental research. In this work the transmission properties of Suprasil 2 from Heraeus with an absorption edge at very low wavelengths is investigated. The absorption edge of this quartz glass shifts from 170 to 180 nm between 789 and 1129 K. The Urbach rule is discussed for the characterization of the temperature dependent transmission curves. The results are applied to the diagnostics of the Hg 185 nm line from a high pressure mercury discharge lamp.

  15. Case report: laparoscopic pyeloplasty with pyelolithotomy in crossed fused ectopia.

    PubMed

    Modi, Pranjal; Goel, Rajiv; Dodia, Sharad

    2006-03-01

    An 8-year-old boy with right flank pain was found on ultrasonography and intravenous urography to have hydronephrosis secondary to ureteropelvic junction obstruction with calculi in the lower pole of the right kidney and a fusion anomaly. Transperitoneal laparoscopic dismembered pyeloplasty and removal of calculi was carried out. The patient had uneventful recovery and is doing well at 6 months' follow-up. To our knowledge, this is the first reported case of laparoscopic pyeloplasty with pyelolithotomy in crossed fused ectopic kidneys in the pediatric population. PMID:16548727

  16. Modeling and optimization of multimode fused fiber combiners

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Yu, Hao; Califano, Alessio; Braglia, Andrea; Perrone, Guido

    2016-03-01

    An effective method to predict the performance of multimode fused fiber combiners is presented. The realization of high power devices is strongly affected by the specific application, for instance whether used in fiber or in direct-diode lasers, and thus usually requires costly and time-consuming trial-and-error procedures. The proposed approach, which is based on ray tracing and statistical analysis, allows analyzing a-priori the impact of fiber dimensions, combiner geometry, glass material properties and laser beam quality on the coupling efficiency, therefore reducing the fabrication runs. Examples of application to 7-to-1 and 19-to-1 combiners are given and compared with experimental results.

  17. 21 CFR 573.225 - 1,3-Butylene glycol.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.225 1,3-Butylene glycol. The food additive 1,3-butylene glycol (1,3-butanediol) may... 21 Food and Drugs 6 2011-04-01 2011-04-01 false 1,3-Butylene glycol. 573.225 Section 573.225...

  18. 21 CFR 573.225 - 1,3-Butylene glycol.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.225 1,3-Butylene glycol. The food additive 1,3-butylene glycol (1,3-butanediol) may... 21 Food and Drugs 6 2013-04-01 2013-04-01 false 1,3-Butylene glycol. 573.225 Section 573.225...

  19. 21 CFR 573.225 - 1,3-Butylene glycol.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.225 1,3-Butylene glycol. The food additive 1,3-butylene glycol (1,3-butanediol) may... 21 Food and Drugs 6 2010-04-01 2010-04-01 false 1,3-Butylene glycol. 573.225 Section 573.225...

  20. 21 CFR 573.225 - 1,3-Butylene glycol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.225 1,3-Butylene glycol. The food additive 1,3-butylene glycol (1,3-butanediol) may... 21 Food and Drugs 6 2014-04-01 2014-04-01 false 1,3-Butylene glycol. 573.225 Section 573.225...