Science.gov

Sample records for policlosrodibenzofuranos pcdfs por

  1. Atmospheric concentrations of PCDDs/PCDFs in Southern California

    SciTech Connect

    Hunt, G.T.; Maisel, B.E. )

    1992-05-01

    A comprehensive air toxics measurements program designed to establish baseline concentrations of atmospheric polychlorinated dioxins and dibenzofurans (PCDDs/PCDFs) in the South Coast Air Basin has been completed. The program utilized state-of-the-art sampling and laboratory analysis techniques (HRGC/HRMS) to quantify the fifteen 2,3,7,8-substituted PCDDs/PCDFs congeners of primary toxicological significance. This study, which included nine discrete sampling sessions between December 1987 and March 1989, provides the first systematic assessment of ambient PCDDs/PCDFs concentrations in the state of California. The highest PCDDs/PCDFs concentrations noted during this study occurred in December 1987. This period was dominated by off-shore air flows, suggesting a regional air mass and transport phenomena. Concentrations of the PCDDs/PCDFs were diminished markedly in subsequent sampling sessions where air flow patterns were primarily of on-shore or of coastal origin. Typical of combustion source profiles, 1,2,3,4,6,7,8-HpCDD was the predominant 2,3,7,8-substituted species and most prevalent PCDD after OCDD. The congener of highest toxicological significance, 2,3,7,8-TCDD, was reported below the 10-20 fg/m{sup 3} detection limit for most of the ambient air samples selected for analysis.

  2. SAMPLING AND ANALYSIS OF PCDDS AND PCDFS IN STATIONARY SOURCE EMISSION AIR SAMPLES

    EPA Science Inventory

    Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzo-furans (PCDFs) are two classes of extremely toxic compounds produced and emitted into the environment as a result of combustion processes. lthough no standard method for sampling or analysis of PCDDs and PCDFs ...

  3. Enrichment of PCDDs/PCDFs in peripheral utilities of the municipal solid waste incineration facility.

    PubMed

    Kim, Sam-Cwan; Song, Geum-Ju; Seok, Kwang-Seol; Ko, Yun-Hwa; Hunsinger, Hans

    2013-05-01

    This study was performed to suggest the improvements through measuring the amounts of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), re-synthesized in peripheral utilities (PUs) of a commercial-scale municipal solid waste incineration facility (MSWIF) where a few research results existed. The PUs examined in this study consisted of air pre-heaters (APHs) and gas/gas re-heater (GGRH) and kerosene-fired duct burner for selective catalytic reduction (SCR) process. PCDDs/PCDFs in flue gas were simultaneously measured at the inlet and outlet of PUs. Flue gas was cooled down from 380 °C to 249 °C by exchanging the heat with fresh air in APHs, and then heated up to 383 °C by GGRH and duct burner from 164 °C at the outlet of bag filter. The results showed that PCDDs/PCDFs were 3-4 times higher within this temperature range of PUs. In comparison of PCDDs/PCDFs concentrations at the inlet with those at the outlet of PUs, particulate-phase PCDDs/PCDFs were about 9.5-10 times enriched while gaseous-phase ones were decreased by about 33-41%. The PCDDs/PCDFs re-synthesized in the PUs, where PCDDs were relatively higher than PCDFs, showed somewhat different patterns compared to those formed at incinerators and emitted at stack. Through the investigations for PUs, we conclude that the PUs used in MSWIFs was a potential source for de novo synthesis of PCDDs/PCDFs. PMID:23415710

  4. Congener specific biotransformation and bioaccumulation of PCDDs and PCDFs from fly ash in fish

    SciTech Connect

    Sijm, D.T.H.M.; Opperhuizen, A. . Research Inst. of Toxicology, Environmental Chemistry Group); Wever, H. . Dept. of Environmental and Toxicological Chemistry)

    1993-10-01

    Biotransformation may be responsible for the lack of bioaccumulation of a number of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). Goldfish (Carassius auratus) that were exposed to PCDDs and PCDFs, and piperonylbutoxide (PBO) in water bioconcentrated significantly more congeners than goldfish exposed to PCDDs and PCDFs only. Monooxygenase activity, which is responsible for the oxidation of specific PCDD and PCDF congeners in untreated fish, was inhibited by fish treated with PBO. In the PBO-treated group and in the control group, congeners with all lateral positions substituted were found. Congeners that lack chlorine substitution on one or more of the lateral positions substituted were found. Congeners that lack chlorine substitution on one or more of the lateral (2,3,7,8) positions and congeners that have all lateral positions chlorinated were found only in PBO-treated fish. Congeners that have at least one free lateral position were therefore assumed to be biotransformed. There was no relationship between the octanol/water partition coefficient and biotransformed. There was no relationship between the octanol/water partition coefficient and biotransformation of the PCDDs and PCDFs. No limitation of uptake for higher chlorinated PCDD and PCDF congeners was found.

  5. The biomagnification of PCBs, PCDDs, PCDFs in a simplified laboratory food chain

    SciTech Connect

    Taplin, B.; Pruell, R.; McGovern, D.; McKinney, R.

    1995-12-31

    The trophic transfer and biomagnification potential of polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs), were investigated in a simplified marine benthic food chain. Polychaetes, Nereis virens were exposed to contaminated sediment and fed to juvenile lobsters, Homarus americanus exposed to the same sediment for 112 days. Time series uptake and depuration measurements were made for lobster muscle and hepatopancreas. A nonlinear model (BIOFAC) was used to calculate uptake and depuration rate constants, bioaccumulation factors, and steady state concentrations for PCBs, PCDDs, and PCDFs. Biomagnification factors (BMFs), on a lipid weight basis, were calculated for both tissues. Lobsters accumulated PCDDs, PCDFs, and PCBs from contaminated sediment and food (polychaetes). Of the two tissues, lobster hepatopancreas, showed the highest concentrations for all compounds analyzed. Of the PCDDs and PCDFs studied, only 2,3,7,8-tetrachlorodibenzodioxin, 2,3,7,8-tetrachlorodibenzofuran, 2,3,4,7,8-pentachlorodibenzofuran, and 1,2,3,4,7,8-hexachlorodibenzofuran were detected in lobster muscle and hepatopancreas tissues. Of the PCB congeners studied, 2,2{prime},4,4{prime},5,5{prime} hexachlorobiphenyl reached the highest concentration in lobster muscle and hepatopancreas. Lobsters also accumulated non-ortho substituted PCBs in both tissues.

  6. PCDDs, PCDFs and dioxin-like PCBs in food of animal origin (Slovakia).

    PubMed

    Chovancová, Jana; Kocan, Anton; Jursa, Stanislav

    2005-12-01

    The levels of 17 toxic polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and 12 non-ortho and mono-ortho polychlorinated biphenyls (PCBs) in 73 foodstuff samples of animal origin collected from shops and small farms in selected districts of Slovak Republic are presented in this paper. The concentrations expressed as WHO-TEQ in analysed samples ranged for PCDDs/PCDFs from 0.25 pg/g fat in pork to 75 pg/g fat in cod liver. The TEQ concentrations of non-ortho PCBs were between 0.007 and 181 pg/g fat and mono-ortho PCBs between 0.0083 and 66.5 pg/g fat. The mean concentrations in freshwater fish and imported species of marine fish were 0.089 pg TEQ/g fresh weight for PCDDs/PCDFs, 0.17 pg TEQ/g fresh weight for non-ortho PCBs and 0.034 pg TEQ/g fresh weight for mono-ortho PCBs. The mean total concentration of PCDDs/PCDFs and dioxin-like PCBs in samples of infant milk formula imported from EU countries was 0.98 pg TEQ/g fat. PMID:16291405

  7. UPTAKE AND DEPURATION STUDIES OF PCDDS AND PCDFS IN FRESHWATER FISH

    EPA Science Inventory

    The bioavailability of PCDD/PCDFs from municipal incinerator fly ash and sediment to freshwater fish has been studied. A preference to selectively bioaccumulate PCDD/PCDF isomers substituted in the 2,3,7, and 8 positions was observed. The depuration half life of 2,3,7,8-TCDD from...

  8. TOXIC EQUIVALENCY FACTORS (TEFS) FOR PCBS, PCDDS, PCDFS FOR HUMANS AND WILDLIFE

    EPA Science Inventory

    An expert meeting was organized by the World Health Organization (WHO) and held ih Stockholm on 15-18 June 1997. The objective of this meeting was to derive cohsensus toxic equivalency factors (TEFs) for polychlorinated didbenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and dio...

  9. A pilot and field investigation on mobility of PCDDs/PCDFs in landfill site with municipal solid waste incineration residue.

    PubMed

    Osako, Masahiro; Kim, Yong-Jin; Lee, Dong-Hoon

    2002-09-01

    A field investigation by boring was carried out in a landfill site primarily with municipal solid waste incineration residue. From the collected core samples, vertical profiles of homologous content of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs) in the landfill layer were traced and the behavior of PCDDs/PCDFs was examined. In addition, a pilot-scale study was conducted on the PCDDs/PCDFs leached from incineration fly ash and the treated one using large landfill simulation columns (lysimeters) and the leaching behavior of PCDDs/PCDFs was examined. As a result, it was found that the coexistence of dissolved coloring constituents (DCCs), which might be composed of constituents like dissolved humic matters having strong affinity for hydrophobic organic pollutants, could enhance the leachability of PCDDs/PCDFs, thus contributing to the vertical movement and leaching behavior of PCDDs/PCDFs in the landfill layers of the incineration residue. Moreover, it is highly probable that DCCs derive from the unburned carbon in the bottom ash mixed and buried with the fly ash containing a high content of PCDDs/PCDFs. PMID:12222779

  10. COMPARING PCDDS, PCDFS, AND DIOXIN-LIKE PCBS IN FARM-RAISED AND WILD-CAUGHT CATFISH FROM SOUTHERN MISSISSIPPI

    EPA Science Inventory

    Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) [hereafter referred to as ¿dioxin-like compounds¿] are persistent environmental contaminants that have been found to be ubiquitous in environmental media and bio...

  11. PCDDs, PCDFs, and PCBs co-occurrence in TiO2 nanoparticles.

    PubMed

    Ctistis, Georgios; Schön, Peter; Bakker, Wouter; Luthe, Gregor

    2016-03-01

    In the present study, we report on the co-occurrence of persistent organic pollutants (POPs) adsorbed on nanoparticular titanium dioxide (TiO2). We report on the finding of polychlorinated dibenzodioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) on the surface of commercially available TiO2 nanoparticles, being formed during the fabrication process of the TiO2. Thereby, the samples comprise PCBs with higher congener numbers or, in the absence of PCBs, a high concentration of PCDDs and PCDFs. This new class of POPs on an active catalytic surface and the great range of applications of nanoparticular TiO2, such as in color pigments, cosmetics, and inks, give rise to great concern due to their potential toxicity. PMID:26545886

  12. Unintentional formed PCDDs, PCDFs, and DL-PCBs as impurities in Chinese pentachloronitrobenzene products.

    PubMed

    Huang, Jun; Gao, Jie; Yu, Gang; Yamazaki, Norimasa; Deng, Shubo; Wang, Bin; Weber, Roland

    2015-10-01

    Pentachloronitrobenzene (PCNB) products have been reported to contain relatively high levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) as impurities. No data was available for Chinese PCNB products which are still produced and used in China. Therefore, we analysed Chinese PCNB products, including two raw pesticides and three formulations available on the market. In all samples, PCDDs, PCDFs, and dioxin-like polychlorinated biphenyls (DL-PCBs) were detected at levels exceeding Japanese regulation limits. The concentrations of PCDDs and PCDFs (0.16 to 0.93 ng TEQ g(-1)) were lower than the PCNB formulations measured from the Australian market (3.9 ng TEQ g(-1)). However, the Toxic Equivalent (TEQ) contribution from DL-PCBs (0.7 to 2.5 ng TEQ g(-1)) to total TEQ was higher compared to PCDDs and PCDFs. This discovery demonstrated that it is necessary to consider the DL-PCBs impurity in organochlorine pesticides and other organochlorine chemicals in particular chlorinated aromatic compounds for adequate risk assessment. In addition to DL-PCBs, other unintentionally POPs-hexachlorobenzene (HCB) (3.7 to 52 ng g(-1)) and pentachlorobenzene (PeCBz) (0.04 to 0.3 ng g(-1)) which are listed in the Stockholm Convention-were detected in the PCNB samples. The PCNB production steps were assessed for their unintentional POPs formation potential. Thermolysis of the aromatic compounds using iron chloride (FeCl3) as catalyst is suggested as relevant production step for (DL-)PCBs formation. Since the levels in the formulated PCNB recalculated to active ingredient were higher compared to the raw pesticide, the formulation process (e.g., milling) may also have had an influence on additional PCDD/Fs and PCBs formation. PMID:25167828

  13. The biomagnification of PCBs, PCDDs, and PCDFs in a simplified laboratory food chain

    SciTech Connect

    Taplin, B.; Pruell, R.; McGovern, D.; McKinney, R.

    1995-12-31

    Polychaetes Nereis virens were exposed to contaminated sediment and fed to juvenile lobsters, Homarus americanus exposed to the same sediment for 112 days. Time series uptake and deputation measurements were made for lobster muscle and hepatopancreas. A nonlinear model (BIOFAC) was used to calculate uptake and deputation rate constants, bioaccumulation factors, and steady state concentrations for PCBS, PCDDS, and PCDFS. Biomagnification factors (BMFs), on a lipid weight basis, were calculated for both tissues. Lobsters accumulated PCDDS, PCDFS, and PCBs from contaminated sediment and food (polychaetes). Of the two tissues, lobster hepatopancreas showed the highest concentrations for all compounds analyzed. Of the PCDDs and PCDFs studied, only 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TCDD), 2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF), 2,3,4,7,8-pentachlorodibenzofuran, and 1,2,3,4,7,8-hexachlorodibenzofuran were detected in lobster muscle and hepatopancreas tissues. Of the PCB congeners studied, 2,2{prime},4,4{prime},5,5{prime} hexachlorobiphenyl (UPAC No. 153) reached the highest concentration in lobster muscle and hepatopancreas. Lobsters also accumulated non-ortho substituted PCBs in both tissues. Biomagnification factors (BMFS) were calculated for lobster muscle and hepatopancreas on a lipid weight basis using steady-state concentrations. BMFs for lobster hepatopancreas were generally higher than those for muscle. Of the PCDDs and PCDFs studied, only 2,3,7,8-TCDD and 2,3,7,8-TCDF were biomagnified in lobster hepatopancreas and muscle compared with levels in the polychaetes. Selected PCB congeners were also biomagnified in both tissues. PCB congeners with log{sub 10} K{sub ow} values > 6.5 had higher BMFs for hepatopancreas tissue than compounds with lower K{sub ow`s}. No trend was evident regarding log{sub 10} K{sub ow} of PCBs and BMFs for lobster muscle.

  14. Method validation program for the long duration sampling of PCDDs/PCDFs in ambient air

    SciTech Connect

    Maisel, B.E.; Hunt, G.T.; Hoyt, M.P.; Rowe, N.; Scarfo, L.

    1994-12-31

    A method validation program was completed to assess the technical viability of extended, long duration sampling periods (15- and 30-day) for the collection of PCDDs/PCDFs in ambient air in lieu of the 48-hour sampling periods typically employed. This long duration approach, if successful, would provide measurements data more representative of average ambient PCDDs/PCDFs levels on an annual basis, and hence provide enhanced support of the 1.0 pg/m{sup 3} annual ambient standard for PCDDs/PCDFs (expressed at 1987 EPA toxic equivalents) required by Connecticut regulation. The method validation program utilized nine collocated PUF samplers which were operated for 15-day and 30-day periods during each of two seasonal monitoring campaigns (winter and summer). Samples were analyzed using high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) based on EPA Method 8290. Each PUF cartridge consisted of two foam halves; the top half PUF and filter were analyzed as a single sample separately from the bottom half PUF section. This approach provided an assessment of analyte breakthrough using the sampling system for large sample volumes of approximately 4,000 m{sup 3} and 8,000 m{sup 3} for the 15-day and respectively.

  15. PCDDs (polychlorinated dibenzo-p-dioxins) and PCDFs (polychlorinated dibenzofurans) in humans

    SciTech Connect

    Swanson, S.E. ); Erickson, M.D. )

    1990-01-01

    Numerous instances of human exposure to polychlorinated dibenzo-p- dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) have been documented. Following the development of sufficiently specific and sensitive analytical methods during the past few years, many reports have appeared on PCDD and PCDF levels in human blood and adipose tissues. Studies have examined the PCDD and PCDF levels resulting from accidental and occupational exposures of various groups, including chemical plant workers, forestry and tannery workers, and Niet Nam veterans who had handled Agent Orange. The general background levels in the US, Federal Republic of Germany, Japan, and Sweden were also determined. The results of these studies indicate that a background level of PCDDs and PCDFs is present in the overall population. In some cases, individuals exposed to specific PCDDs or PCDFs exhibit higher levels than the general population. Isomer distribution patterns are relatively consistent and indicative of sources and metabolism. This paper reviews the available data on human PCDD and PCDF levels in exposed and general populations. 15 refs., 4 figs.

  16. Determination of body burdens for polychlorinated dibenzo-'p'-dioxins (PCDDS) and polychlorinated dibenzofurans (PCDFS) in california residents. Final report

    SciTech Connect

    Stanley, J.S.; Bauer, K.M.; Turman, K.; Boggess, K.; Cramer, P.

    1989-10-26

    Determination of body burden levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs and PCDFs) in residents of California was conducted based on a stratified survey design. Stratification factors included two geographical locations (San Francisco and Los Angeles), three age groups (12 to 34, 35 to 49, and 50 plus years), and sex. A total of 57 adipose tissue specimens were collected across the 12 specific strata. Analysis for the specific 2,3,7,8-substituted isomers was achieved based on high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). Detectable levels of PCDDs and PCDFs were measured in all samples with isomer patterns consistent with findings in other studies conducted within the United States, Canada, and Europe. A questionnaire focused on the lifestyles of participants in the program was conducted to determine residual and occupational information and possible exposure routes to PCDDs and PCDFs. The data base provides a reference for comparison in future human monitoring programs.

  17. Determination of PCDDs, PCDFs, and PCBs in California peregrine falcons (Falco peregrinus) and their eggs

    SciTech Connect

    Jarman, W.M.; Burns, S.A. ); Chang, R.R.; Stephens, R.D. ); Norstrom, R.J.; Simon, M. ); Linthicum, J. )

    1993-01-01

    Levels of organochlorine compounds; polychlorinated biphenyls (PCBs), including nonortho congeners; polychlorinated dibenzo-p-dioxins (PCDDs); and polychlorinated dibenzofurans (PCDFs) were determined in seven California peregrine falcon eggs (Falco peregrinus) collected form five sites between the years 1983 to 1988; one immature falcon was analyzed for PCDDs and PCDGs only. All of the identified PCDDs and PCDFs were 2,3,7,8-substituted. The major PCDD and PCDF congeners identified in the eggs were 1,2,3,7,8-pentachlorodibenzo-p-dioxin (1,2,3,7,8-PnCDD) at a geometric mean value of 11 ng/kg, 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin (1,2,3,6,7,8-HxCDD) at a mean value of 11 ng/kg 2,3,7,8-tetrachlorodibenzofuran (TCDF) at a mean value of 6.2 ng/kg, and 2,3,4,7,8-pentachlorodibenzofuran (2,3,4,7,8-PnCDF) at a level of 6.5 ng/kg. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) was present at a mean value of 5.7 ng/kg. Values of p,p[prime]-DDE in the eggs ranged from 7,100 to 26,000 [mu]g/kg, with a mean value of 12,000 [mu]g/kg. [Sigma]PCB levels ranged from 1,400 to 13,000 [mu]g/kg, with a mean value of 4,800 [mu]g/kg. The mean values of the non-ortho congeners 3,4,4[prime]-trichlorobiphenyl (PCB 37); 3,3[prime]4, 4[prime]-tetrachlorobiphenyl (PCB 77); 3,3[prime]4, 4[prime]5-pentachlorobiphenyl (PCB 126); and 3,3[prime]4, 4[prime],5,5[prime]-hexachlorobiphenyl (PCB 169) were 0.18, 0.93, 1.0, and 0.14 [mu]g/kg, respectively. TCDD equivalents (TEQs) were calculated for the mean values of PCDDs, PCDFs, and non-ortho-PCBs in the eggs. Total TEQs in the eggs was 120 ng/kg; PCB 126 accounted for 83% of the TEQs.

  18. Hydrodechlorination/detoxification of PCDDs, PCDFs, and co-PCBs in fly ash by using calcium polysulfide.

    PubMed

    Tabata, Masaaki; Ghaffar, Abdul; Shono, Akifumi; Notomi, Keiichi

    2013-02-01

    Dioxins like polychlorinated dibenzo-p-dioxins (PCSDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) are mainly emitted from waste incinerators (WIs) and have become an international research focus because of its serious concerns over the adverse health effects. The detoxification of PCCDs/Fs and PCBs is very difficult because of their stable chemical structure. A significant hydrodechlorination/detoxification of polychlorinated 1-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) were achieved in fly ash by using an aqueous mixture of calcium hydroxide and sulfur. Two different fly ashes were studied: originating from municipal waste incinerator (FA1) and industrial waste incinerator (FA2). They were heated with the aqueous mixture at 150°C for 30 or 60 min with agitation. Higher decomposition (87%) and detoxification (87.7%) of PCDD/Fs and PCBs were achieved at 150°C with two runs; every run was for 30 min, compared to one run for 60 min. FA2 gave higher decomposition and detoxification as compared to FA1, which might be due to higher metal content that played a catalytic role to decompose and detoxify the PCDDs, PCDFs and PCBs. The decomposition and detoxification of PCDFs in fly ash was higher than PCDDs and was augmented with increasing number of chlorides on aromatic compounds. As the highly significant decomposition and detoxification of higher concentration of PCDD/Fs and PCBs were achieved in 1 hour without additive catalyst and at low temperature of 150°C, therefore, the developed method is cost effective and most suitable to apply on commercial/industrial level. The detail results of hydrodechlorination/detoxification of PCDD, PCDFs at different conditions are described and its mechanism is discussed. PMID:23200792

  19. Levels of toxic PCBs, PCDDs and PCDFs in biotic and abiotic samples from Galveston Bay, Texas

    SciTech Connect

    Gardinali, P.; Wade, T.

    1995-12-31

    Concentrations of di-, mono-, non-ortho PCB congeners as well as the seventeen 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) were measured in American oyster, blue crab, hardhead catfish liver and sediment samples collected from five sites in the Galveston Bay System. In general, when measuring sediments and sentinel organisms, a geographical gradient of contaminant load is observed between the heavily industrialized and the open bay sites. Although sediment concentrations are relatively low at most stations, toxic PCBs, PCDDs and PCDFs are strongly bioconcentrated in all three organisms analyzed. Levels of 2,3,7,8-TCDD ranged from 1.15 to 16.4 pg/g in the oysters, 1.10 to 138 pg/g in the blue crabs and, 11.0 to 101 pg/g in the catfish livers. 2,3,7,8-TCDD concentrations in sediments ranged from non-detected to 4.44 pg/g. Concentrations of 2,3,7,8-TCDF ranged from 2.31 to 50.6 pg/g in the oysters, 5.77 to 385 pg/g in the blue crabs and, 5.57 to 8.04 pg/g in the catfish livers, while sediment concentrations were between 0.65 to 7.46 pg/g. When the toxicity equivalent factor (TEF) approach was used to estimate the 2,3,7,8-TCDD toxic equivalents (TEQs), the non-ortho PCB congeners were the major TEQ contributors for the all organisms (29 to 74%). In contrast, the TEQ for the sediment samples were largely dominated by the contribution from PCDDs and PCDFs. The results also suggest that oysters, in spite of their lower concentrations, are more valuable for biomonitoring the availability of halogenated aromatic hydrocarbon contaminants.

  20. Spatial and temporal trends of PCDDs and PCDFs in bivalve mollusc coming from Galicia (2000-2005). Possible relationship between biometric parameters and PCDDs and PCDFs levels.

    PubMed

    Carro, N; García, I; Ignacio, M; Mouteira, A

    2008-08-01

    Levels and specific profiles of PCDD/F congeners were determined in bivalve mollusc coming from several Rías (estuarine bays) in Galicia (Spanish northwest Atlantic coast). Three species of bivalve mollusc, Mytilus galloprovincialis, Cerstoderma edulis and Ostrea edulis, from several points of littoral collected in the period from 2000 to 2005 were analysed. WHO-TEQ concentrations ranged from 0.08 to 1.62 pg g(-1) wet weight, values below the maximum concentration established by the EU. The PCDD/PCDF congeners profile in the studied samples was dominated by 2,3,7,8-TCDF and 2,3,4,7,8-PeCDF. The possible influence between biometric parameters (fat and condition index) and the culture type of mussel (wild or raft) on PCDDs and PCDFs levels were studied using statistical analysis. The coefficients of Pearson product-moment correlation indicated the existence of positive significant relationship between 2,3,7,8-TCDF and 2,3,4,7,8-PeCDF levels and fat content. There was not correlation between condition index and PCDD/Fs content. ANOVA also revealed there were significant differences between SigmaPCDD/Fs, 2,3,7,8-TCDF and 2,3,4,7,8-PeCDF levels in raft and wild mussels. Spatial and temporal trends were supported by patterns in ANOVA, using a general linear model (GLM) showing a clear separation in the composition of these compounds in more and less contaminated Rías and a decrease of PCDD/FS levels along the years. PMID:18602662

  1. CHARACTERIZATION OF PCB (POLYCHLORINATED BIPHENYL) TRANSFORMER/CAPACITOR FLUIDS AND CORRELATION WITH PCDDS (POLYCHLORINATED DIBENZO-P-DIOXINS) AND PCDFS (POLYCHLORINATED DIBENZOFURANS) IN SOOT

    EPA Science Inventory

    Dielectric fluids in transformers and capacitors often contain polychlorinated biphenyls (PCBs) or chlorobenzenes. These substances may generate polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) under certain conditions of combustion/pyrolysis. W...

  2. Levels of PCDDs and PCDFs in human milk from populations in Madrid and Paris

    SciTech Connect

    Gonzalez, M.J.; Hernandez, L.M.; Jimenez, B.

    1996-02-01

    Human breast milk represents a good substrate to examine the polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) background contamination of a population and also supplies important information about the exposure risk for nursing infants. Although adipose tissue and blood samples are commonly studied in the literature milk Dioxin levels are more specifically of concern because of the facility of sampling and also the potential health damage which may be caused to the breastfed babies by those highly toxic synthetic chemicals. The occurrence of dioxins in mother milk among the general population in all countries studied until now, has confirmed a widespread pollution and intake of those compounds. Dietary and other sources such as contaminated chemicals, industrial activity, waste combustion and leaded car gasoline may be responsible for such a contamination, and also for the differences among levels found in different countries. Human contamination by PCDDs and PCDFs from the environment is clearly a multisource problem. Human milk as well as other human fluids studies up to know have only found the presence of 2,3,7,8 substituted PCDD or PCDF congeners present. The reason for this congener specific retention is usually explained by the metabolic conversion on the 2,3,7, and 8 lateral positions in combination with high binding affinities for the cytosolic receptor proteins.

  3. Toxic equivalency factors (TEFs) for PCBs, PCDDs, PCDFs for humans and wildlife

    USGS Publications Warehouse

    Van Den, Berg, M.; Birnbaum, L.; Bosveld, A.T.C.; Brunstrom, B.; Cook, P.; Feeley, M.; Giesy, J.P.; Hanberg, A.; Hasegawa, R.; Kennedy, S.W.; Kubiak, T.; Larsen, J.C.; Van Leeuwen, F. X. R.; Liem, A.K.D.; Nolt, C.; Peterson, R.E.; Poellinger, L.; Safe, S.; Schrenk, D.; Tillitt, D.; Tysklind, M.; Younes, M.; Waern, F.; Zacharewski, T.

    1998-01-01

    An expert meeting was organized by the World Health Organization (WHO) and held in Stockholm on 15-18 June 1997. The objective of this meeting was to derive consensus toxic equivalency factors (TEFs) for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and dioxinlike polychlorinated biphenyls (PCBs) for both human, fish, and wildlife risk assessment. Based on existing literature data, TEFs were (re)evaluated and either revised (mammals) or established (fish and birds). A few mammalian WHO-TEFs were revised, including 1,2,3,7,8-pentachlorinated DD, octachlorinated DD, occachlorinated DF, and PCB 77. These mammalian TEFs are also considered applicable for humans and wild mammalian species. Furthermore, it was concluded that there was insufficient in vivo evidence to continue the use of TEFs for some di-ortho PCBs, as suggested earlier by Ahlborg et al. In addition, TEFs for fish and birds were determined. The WHO working group attempted to harmonize TEFs across different taxa to the extent possible. However, total synchronization of TEFs was not feasible, as there were orders of a magnitude difference in TEFs between taxa for some compounds. In this respect, the absent or very low response of fish to mono-ortho PCBs is most noticeable compared to mammals and birds. Uncertainties that could compromise the TEF concept were also reviewed, including nonadditive interactions, differences in shape of the dose-response curve, and species responsiveness. In spite of these uncertainties, it was concluded that the TEF concept is still the most plausible and feasible approach for risk assessment of halogenated aromatic hydrocarbons with dioxinlike properties.

  4. PCDDs, PCDFs, PCBs and OCPs in sediments from selected areas in the Slovak Republic.

    PubMed

    Čonka, Kamil; Chovancová, Jana; Stachová Sejáková, Zuzana; Dömötörová, Milena; Fabišiková, Anna; Drobná, Beáta; Kočan, Anton

    2014-03-01

    Within our research project, 34 river bottom sediments were collected in 2006-2007 at five areas across Slovakia with industrial sources of persistent organic pollutants (Košice, Krompachy, Nemecká, Šala, Nováky) and one background area (Starina). Sediments were analyzed for seven 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and 10 dibenzofurans (PCDFs), 12 dioxin-like and 6 indicator polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB) and 1,1,1,-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT) with 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE). Analytical procedure based on accelerated solvent extraction followed by a semi-automated clean-up and fractionation was used. Determination of target compounds was performed by HRGC-HRMS analysis. Total WHO toxic equivalent WHO1998-PCDD/F/dl-PCB-TEQ concentrations ranged from 0.26 to 559 pg TEQ g(-1) dry matter (dm), with a median 2.2 pg TEQ g(-1) dm. The sums of six indicator PCBs were in the range 0.56-1014 ng g(-1) dm, with a median 11.8 ng g(-1) dm. The concentrations of organochlorine pesticides HCB and p,p'-DDE/DDT varied from 0.15 to 34.8 ng g(-1) dm, with a median 0.91 ng g(-1) dm and 0.46-34.1 ng g(-1)dm, with a median 6.7 ng g(-1)dm, respectively. The most abundant congeners in all sediment samples among dioxins, furans and PCBs were OCDD, 1,2,3,4,6,7,8-HpCDF, PCB-118 and PCB-153. PMID:24210452

  5. Toxic equivalency factors (TEFs) for PCBs, PCDDs, PCDFs for humans and wildlife.

    PubMed Central

    Van den Berg, M; Birnbaum, L; Bosveld, A T; Brunström, B; Cook, P; Feeley, M; Giesy, J P; Hanberg, A; Hasegawa, R; Kennedy, S W; Kubiak, T; Larsen, J C; van Leeuwen, F X; Liem, A K; Nolt, C; Peterson, R E; Poellinger, L; Safe, S; Schrenk, D; Tillitt, D; Tysklind, M; Younes, M; Waern, F; Zacharewski, T

    1998-01-01

    An expert meeting was organized by the World Health Organization (WHO) and held in Stockholm on 15-18 June 1997. The objective of this meeting was to derive consensus toxic equivalency factors (TEFs) for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and dioxinlike polychlorinated biphenyls (PCBs) for both human, fish, and wildlife risk assessment. Based on existing literature data, TEFs were (re)evaluated and either revised (mammals) or established (fish and birds). A few mammalian WHO-TEFs were revised, including 1,2,3,7,8-pentachlorinated DD, octachlorinated DD, octachlorinated DF, and PCB 77. These mammalian TEFs are also considered applicable for humans and wild mammalian species. Furthermore, it was concluded that there was insufficient in vivo evidence to continue the use of TEFs for some di-ortho PCBs, as suggested earlier by Ahlborg et al. [Chemosphere 28:1049-1067 (1994)]. In addition, TEFs for fish and birds were determined. The WHO working group attempted to harmonize TEFs across different taxa to the extent possible. However, total synchronization of TEFs was not feasible, as there were orders of a magnitude difference in TEFs between taxa for some compounds. In this respect, the absent or very low response of fish to mono-ortho PCBs is most noticeable compared to mammals and birds. Uncertainties that could compromise the TEF concept were also reviewed, including nonadditive interactions, differences in shape of the dose-response curve, and species responsiveness. In spite of these uncertainties, it was concluded that the TEF concept is still the most plausible and feasible approach for risk assessment of halogenated aromatic hydrocarbons with dioxinlike properties. PMID:9831538

  6. Identification, Quantification, and Toxicity of PCDDs and PCDFs in Soils from Industrial Areas in the Central and Eastern Regions of Saudi Arabia.

    PubMed

    Al-Wabel, Mohammad I; El-Saeid, Mohamed H; Usman, Adel R A; Al-Turki, Ali M; Ahmad, Mahtab; Hassanin, Ashraf S; El-Naggar, Ahmed H; Alenazi, Khaled K H

    2016-05-01

    This study was conducted to identify and quantify polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in soil samples collected from selected industrial areas in the central and eastern regions of Saudi Arabia. All the investigated compounds of PCDDs/PCDFs were identified in the studied locations. The average concentrations of PCDDs (sum of seven congeners measured) ranged from 11.5 to 59.6 pg g(-1), with a maximum concentration of 125.7 pg g(-1) at an oil refinery station followed by 100.9 pg g(-1) at a cement factory. The average concentrations of PCDFs (sum of 10 congeners measured) accounted for 11.68-19.35 pg g(-1), with a maximum concentration of 38.67 pg g(-1) at the cement factory. It was generally observed that the soil samples collected from industrial areas have substantially high toxicity equivalence (TEQ) values of PCDDs/PCDFs compared to soils of remote areas. Principal component analysis revealed that the cement factories and oil refineries were the primary sources of PCDDs and PCDFs. PMID:27010396

  7. Specific congener profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans in blue mussel in Osaka Bay in Japan: Aqueous solubilities of PCDDs and PCDFs

    SciTech Connect

    Miyata, Hideaki; Takayama, Koji; Mimura, Mayumi; Kashimoto, Takashi ); Fukushima, Shigehiko )

    1989-09-01

    The authors have monitored polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in the coastal waters of Japan by using blue mussel (Mytilus edulis) as a biological indicator. The levels of both chemicals were surmised to closely relate to the number of municipal incinerators and the population densities in the cities adjoining the sampling location. The main contamination source in Osaka Bay, which is heavy polluted with PCDDs and PCDFs, was determined to be the fly ash from municipal waste incinerators based upon analytical results of blue mussel from Osaka Bay sediments, sediments from Osaka Bay, and sediments from a river, which is located near a typical urban municipal waste incinerator. However, there was a remarkable difference in congener profiles of PCDDs and PCDFs between the blue mussel and the fly ash, that is, the mussel mainly contained tetraCDDs and tetraCDFs with congener ratios of 56 {plus minus} 9.7% and 62 {plus minus} 6.0%, respectively, whereas the fly ash contained the higher chlorinated PCDDs and PCDFs as major congeners. In this study, the specific congener profiles of PCDDs and PCDFs in blue mussel were investigated from the point of view of their water solubilities.

  8. Passerine Exposure to Primarily PCDFs and PCDDs in the River Floodplains Near Midland, Michigan, USA

    PubMed Central

    Zwiernik, Matthew J.; Seston, Rita M.; Coefield, Sarah J.; Plautz, Stephanie C.; Tazelaar, Dustin L.; Shotwell, Melissa S.; Bradley, Patrick W.; Kay, Denise P.; Giesy, John P.

    2009-01-01

    House wren (Troglodytes aedon), tree swallow (Tachycineta bicolor), and eastern bluebird (Sialia sialis) tissues collected in study areas (SAs) downstream of Midland, Michigan (USA) contained concentrations of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) greater than in upstream reference areas (RAs) in the region. The sum of concentrations of PCDD/DFs (ΣPCDD/DFs) in eggs of house wrens and eastern bluebirds from SAs were 4- to 22-fold greater compared to those from RAs, whereas concentrations in tree swallow eggs were similar among areas. Mean concentrations of ΣPCDD/DFs and sum 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (ΣTEQsWHO-Avian), based on 1998 WHO avian toxic equivalency factors, in house wren and eastern bluebird eggs ranged from 860 (430) to 1500 (910) ng/kg wet weight (ww) and 470 (150) to 1100 (510) ng/kg ww, respectively, at the most contaminated study areas along the Tittabawassee River, whereas mean concentrations in tree swallow eggs ranged from 280 (100) to 760 (280) ng/kg ww among all locations. Concentrations of ΣPCDD/DFs in nestlings of all studied species at SAs were 3- to 50-fold greater compared to RAs. Mean house wren, tree swallow, and eastern bluebird nestling concentrations of ΣPCDD/DFs and ΣTEQsWHO-Avian ranged from 350 (140) to 610 (300) ng/kg ww, 360 (240) to 1100 (860) ng/kg ww, and 330 (100) to 1200 (690) ng/kg ww, respectively, at SAs along the Tittabawassee River. Concentrations of ΣTEQsWHO-Avian were positively correlated with ΣPCDD/DF concentrations in both eggs and nestlings of all species studied. Profiles of relative concentrations of individual congeners were dominated by furan congeners (69–84%), primarily 2,3,7,8-tetrachlorodibenzofuran and 2,3,4,7,8-pentachlorodibenzofuran, for all species at SAs on the Tittabawassee and Saginaw rivers but were dominated by dioxin congeners at upstream RAs. Electronic supplementary material The online version of this article (doi:10

  9. Assessment of health effects in New York City firefighters after exposure to polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs): the Staten Island Transformer Fire Health Surveillance Project.

    PubMed

    Kelly, Kerry J; Connelly, Edmond; Reinhold, Gustave A; Byrne, Mike; Prezant, David J

    2002-01-01

    Following an electrical transformer fire in Staten Island, New York, a health surveillance program was established for 60 New York City firefighters and emergency medical technicians exposed to polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs). Exposure potential was documented after high levels of PCBs and PCDFs were found on transformer and firefighters' uniforms. Personnel received comprehensive medical examinations, and the results were compared with preexposure values. Serum was analyzed for PCBs, PCDFs, and polychlorinated dibenzo-p-dioxins (PCDDs). Follow-up was conducted 9 mo later. Thirty-two of 58 (55%) firefighters reported initial symptoms, and 3 firefighters required brief medical leave. Pulmonary functions, exercise performance, serum liver functions, and serum lipid profiles were normal or unchanged from preexposure baselines. Serum PCBs averaged 2.92 +/- 1.96 ppb (range = 1.9-11.0 ppb). Five (8%) had serum PCBs that were greater than or equal to 6 ppb. Eight (73%) had a significant decrease (p = .05) in serum PCB level at the time of follow-up. Serum toxic equivalency (TEQ [1998 World Health Organization]) for total PCDDs and PCDFs averaged 39.0 +/- 21.5 (n = 48). Eighteen (38%) had elevated TEQs (i.e., > 40). All firefighters had no short-term heath effects. Modern firefighting uniforms are not meant to replace HAZMAT suits, but these uniforms provide protection from this chemical exposure for most firefighters. PMID:12530594

  10. Bioavailability of PCDDs and PCDFs of fly ash after semi-chronic oral ingestion by guinea pig and Syrian golden hamster

    SciTech Connect

    van den Bery, M.; de Vroom, E.; Olie, K.; Hutzinger, O.

    1986-01-01

    Groups of guinea pigs and syrian golden hamster were fed 2.5% HCl pre-treated fly ash from the electrostatic precipitator of a municipal incinerator during one, two, and three months, respectively, in the diet. The livers were analyzed for tetra-, penta-, and hexa-chlorinated dibenzo(p)dioxines (PCDDs) and dibenzofurans (PCDFs). In the livers of the hamsters 2,3,7,8-substituted PCDDs and PCDFs were the major isomers retained. In the livers of the guinea pigs 2,3,7,8 substituted PCDDs and PCDF congeners were retained, but also a number of otherwise substituted PCDFs. The PCDF congener which had the highest retention in the livers of guinea pigs was 1,2,3,7,8-PnCDF, 11.3% after 95 days. In the livers of the hamsters highest retention was found for 2,3,4,7,8-PnCDF, 8.4% after 95 days. For most 2,3,7,8-substituted PCDDs and PCDFs the retention in the livers of the guinea pigs and hamsters was not significantly different during the whole period, which could indicate a bioconcentration approaching a linear relationship to the administered dose. Constant relative concentrations in the livers were found for the 2,3,7,8-substituted penta- and hexa-chlorinated PCDDs and PCDF in both species during the three time periods.

  11. Effects of oxygen, catalyst and PVC on the formation of PCDDs, PCDFs and dioxin-like PCBs in pyrolysis products of automobile residues.

    PubMed

    Joung, Hyun-Tae; Seo, Yong-Chil; Kim, Ki-Heon; Seo, Yong-Chan

    2006-11-01

    End-of-life vehicles are dismantled to recover reusable parts and then sent to a shredding facility for steel material recovery. The residue generated from the shredding process, so-called automobile shredder residue, is now being mostly disposed in landfill, however landfill will be prohibited in the near future. More recycling and energy recovery must be made by the regulation. The most appropriate method is the thermal treatment that will produce various forms of fuels and less volume of vitrified residue. In this research, an automobile shredder residue was simulated with considering the residue from a shredding factory based on the new vehicle and thermally treated by pyrolysis or gasification to observe the yields of gas, oil and char. In the temperature range of 400-800 degrees C, the yields of gas, oil, and char were 38.7-45.8%, 12.3-18.2%, and 36.0-49.0%, respectively. The optimum pyrolyzing temperature for more oil production was around 600 degrees C. Emission characteristics of the byproducts, PCDDs, PCDFs and dioxin-like PCBs were studied at the temperature of 600 degrees C. The analysis on the concentration and distribution of the isomers in various forms of the products were completed with and without oxygen, PVC, and catalytic metals, in order to observe how the existence of oxygen, PVC, and catalytic metals affect the formation of PCDDs, PCDFs, and dioxin-like PCBs from pyrolysis or gasification process. Without PVC, no PCDDs, PCDFs and dioxin-like PCBs were found in any products. PCDFs were predominant in any conditions. Catalyst and oxygen were found to affect to form more PCDDs, PCDFs, and dioxin-like PCBs. Effects of catalyst and oxygen on the byproduct formation seemed to be similar in oil and gas while that was different in char. PMID:16740293

  12. Annual and seasonal variations in atmospheric PCDDs/PCDFs and dioxin-like PCBs levels in satellite cities of Seoul, Korea during 2003-2009

    NASA Astrophysics Data System (ADS)

    Min, Yoonki; Lee, Meehye; Kim, Donggi; Heo, Jongwon

    2013-10-01

    Long-term measurements of atmospheric polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dl-PCBs) were conducted in six satellite cities of Seoul, the capital of South Korea, from January 2003 to December 2009. Of the six sites, three were located in residential areas (Suwon, Anyang, and Seongnam) and the other three were in industrial areas (Ansan, Bucheon, and Siheung). For the 7 years, the average concentrations of PCDDs/PCDFs and dl-PCBs were higher at industrial sites than those at residential sites, and their lowest and highest concentrations were 0.113 ± 0.073 pg international toxicity equivalency quantity (I-TEQ) m-3 and 0.0071 ± 0.0040 pg World Health Organization (WHO)-TEQ m-3 at Seongnam and 0.625 ± 0.597 pg I-TEQ m-3 and 0.0376 ± 0.0285 pg WHO-TEQ m-3 at Ansan, respectively. The annual averages of these compounds tended to decrease from 2003 to 2009, with the most apparent change in 2006 when the regulation of dioxin emission standard was reinforced for flue gas from incineration facilities. Complying with the reinforced standard, the concentrations of PCDFs were reduced more effectively than those of PCDDs, leading to increase in ratios of PCDDs to PCDFs since 2006. Additionally, a seasonal tendency was observed for PCDDs/PCDFs with higher concentrations in winter than summer, which was opposite for dl-PCBs. This seasonal difference suggests their sources such as combustion processes and volatilization and the influence of synoptic-scale circulation. The congener profiles indicated that 1,2,3,4,6,7,8-HpCDF, OCDF, OCDD, and 1,2,3,4,6,7,8-HpCDD were the most abundant, comprising 65.0% of the 17 toxic 2,3,7,8-substituted PCDDs/PCDFs mass. The three congeners of 2,3‧,4,4‧,5-PeCB, 2,3,3‧,4,4‧-PeCB, and 3,3‧,4,4‧-TeCB comprised 75.9% of the 12 dl-PCBs.

  13. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in surface sediment and bivalve from the Changjiang Estuary, China

    NASA Astrophysics Data System (ADS)

    Wen, Sheng; Hui, Yang; Yang, Fangxing; Liu, Zhengtao; Xu, Ying

    2008-02-01

    Surface sediments and bivalves were collected from the Changjiang Estuary in December 2003 and November 2004, respectively. Polychlorinated dibenzo- p-dioxins (PCDDs) and dibenzofurans (PCDFs) in these samples were measured with high-resolution chromatography (HRGC)/High Resolution Mass Spectrometer (HRMS). The concentrations of total PCDD/Fs and toxic equivalent (TEQ) were 169.83±119.63 and 0.81±0.36 pg/g dry weight (dw) in sediments, and 580.33±240.17 and 7.24±3.65 pg/g dw in bivalves. The homolog compositions of PCDD/Fs were similar among samples, the most abundant congener was octa-chlorinated dibenzo-p-dioxin (OCDD) and then octa-chlorinated dibenzofuran (OCDF) and 1,2,3,4,6,7,8-hepta-chlorinated dibenzo-p-dioxin (HpCDD). The herbicide pentachlorophenol (PCP) and sodium pentachlorophenol (Na-PCP) were proved the main source of PCDD/Fs in this area.

  14. Determination of PCBs, PCDDs and PCDFs in insulating oil samples from stored Chinese electrical capacitors by HRGC/HRMS.

    PubMed

    Huang, Jun; Matsumura, Toru; Yu, Gang; Deng, Shubo; Yamauchi, Makoto; Yamazaki, Norimasa; Weber, Roland

    2011-09-01

    Homologue and congener profiles of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in commercial PCBs formulations are key information for the source identification of PCBs contamination as well as for the risk assessment caused by potential exposure. The isotope dilution technology in combination with high resolution gas chromatography-high resolution mass spectrometry (HRGC/HRMS) has made the accurate determination of such profiles possible. So far, various commercial PCB formulations except Chinese products have been successfully determined. Two PCBs containing insulating oil samples from stored Chinese electrical capacitors have been determined with the same methodology for comparability. The total concentration PCBs in two oil samples were 790,000 μg g(-1) and 720,000 μg g(-1), respectively. TriCBs, TetraCBs, and DiCBs were found to be most abundant. Concentration of dioxins contamination in two samples is 650-670 ng TEQ g(-1), of which 69-71ngTEQg(-1) from PCDD/Fs with the predominant congeners of 1,2,7,8-TeCDF; 2,3,7,8-TeCDF; 2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDF. The contributions of DL-PCBs in total TEQ in both samples were more than 85%. The dioxin-like toxicity in insulating oils contained in electrical capacitors could be considered receive attention as an important dioxins source if such wastes are not managed in an environmentally sound manner. PMID:21741068

  15. Disposition of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in two Norwegian epibenthic marine food webs.

    PubMed

    Ruus, Anders; Berge, John Arthur; Bergstad, Odd Aksel; Knutsen, Jan Atle; Hylland, Ketil

    2006-03-01

    Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) are a group of halogenated hydrocarbons, comprising 210 different, theoretically possible congeners. They are relatively hydrophobic and persistent to biodegradation, thereby rendering them subject to bioaccumulation. This study was conducted in Frierfjord and Eidangerfjord in the Grenland fjord system, Norway, heavily polluted by PCDD/PCDF discharges from the 16,600,859 magnesium production at Herøya from 1951 to 2001. Pooled samples of surface-sediments and the following organisms were collected for the Frierfjord and Eidangerfjord study areas: common shrimp (Crangon crangon), polychaetes (mainly Nereis diversicolor), shore crab (Carcinus maenas), cod (Gadus morhua), flounder (Platichthys flesus), trout (Salmo trutta), herring (Clupea harengus), benthic amphipods and zooplankton. Concentrations of 2,3,7,8-PCDD/Fs were quantified in pooled samples for all species. The relative abundances of stable isotopes of nitrogen (delta(15)N) were evaluated in the organisms as a measure of chemically-derived trophic level. Contrary to earlier studies on other persistent organochlorines, it was found that the concentrations of PCDD/Fs declined with increasing trophic level. Principal Component Analysis (PCA) also showed differences between species in the pattern of PCDD/Fs. Higher chlorinated congeners constituted lower percentages of the PCDD/F-concentrations higher in the food chain as compared to lower trophic levels. In general, congener patterns did not differ between fjords. Infauna (polychaetes) and zooplankton had congener patterns most similar to the pollution source. The results indicate lower accumulation of higher chlorinated congeners in species at higher trophic levels (fish), presumably due to low membrane permeability (high molecular size) and possibly slow transport through intestinal aqueous phases because of low aqueous solubility. PMID:16169571

  16. Dietary intake of PCDDs/PCDFs and coplanar PCBs among the Japanese population estimated by duplicate portion analysis: a low proportion of adults exceed the tolerable daily intake.

    PubMed

    Arisawa, Kokichi; Uemura, Hirokazu; Hiyoshi, Mineyoshi; Satoh, Hiroshi; Sumiyoshi, Yoshio; Morinaga, Kenji; Kodama, Kazunori; Suzuki, Taka-ichiro; Nagai, Masaki; Suzuki, Tsuguyoshi

    2008-10-01

    Dietary intake of dioxins was estimated by duplicate portion analysis of consecutive 3-day food samples among 86 men and 288 women (aged 17-72 years), who were living in 75 different areas of 25 prefectures in Japan. The mean (median) intake of PCDDs+PCDFs, coplanar PCBs (co-PCBs), and total dioxins, expressed on the basis of toxicity equivalents (TEQ), was 0.46 (0.34), 0.59 (0.39), and 1.06 (0.79)pg/kg body weight/day, respectively. Dietary intake was highest in fishing areas, followed by farming and urban areas. In multiple regression analysis, TEQs of PCDDs+PCDFs, co-PCBs, and total dioxins were positively associated with age and intake amount of fish and shellfish, and milk and dairy products, and negatively associated with survey year. There were significant positive correlations between dietary intake and blood levels for TEQs of PCDDs+PCDFs, co-PCBs, and total dioxins (Pearson r=0.35-0.36). The proportion of those whose dietary intake exceeded the tolerable daily intake (TDI), set by the World Health Organization (4pg TEQ/kg/day) and European Union (2pg TEQ/kg/day), was estimated at 2.1% and 10.4%, respectively. However, these proportions were considered to be overestimated because of the effect of day-to-day within-person variation. Therefore, the ratio of within- and between-person variance was estimated by applying random effects one-way analysis of variance to repeated measurements for another group of 35 persons. When the effect of within-person variation of dietary intake was accounted for, the proportion of subjects whose long-term intake exceeded the TDI of WHO and EU decreased to 0.06% and 2.9%, respectively. PMID:18692182

  17. Birth weight and sex of children and the correlation to the body burden of PCDDs/PCDFs and PCBs of the mother.

    PubMed Central

    Vartiainen, T; Jaakkola, J J; Saarikoski, S; Tuomisto, J

    1998-01-01

    Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) were analyzed in 167 random human milk samples from urban and rural areas in Finland. Dietary habits and background information on each mother and child were gathered by questionnaire. Body mass indexes (BMI) before pregnancy and delivery in the rural area were 5-10% higher than in the urban area, but fat content of mother's milk was about 10% higher in the urban area. The mean weights of children (+/- standard deviation) were similar in the rural and urban areas among primiparae, 3,500 +/- 597 g and 3,505 +/- 454 g, respectively, although dioxin international toxic equivalents (I-TEQs) were significantly higher in the urban area. The mother's level of education did not affect the weight of the child, but concentrations of PCDDs/PCDFs (I-TEQ, 2,3,4,7,8-Cl5 dibenzofuran,1,2, 3,7,8-Cl5 dibenzodioxin) and PCBs [sum of PCBs (sumPCB), PCB-TEQ, and most PCB congeners] increased with advanced education. This is considered to be due to differences in the mother's consumption of fish. The birth weight, especially of boys, slightly decreased with increasing concentrations of I-TEQ, 2,3,4,7,8-Cl5 dibenzofuran, 1,2,3, 7,8-Cl5 dibenzodioxin, and 2,3,7,8-Cl4 dibenzodioxin; however, when the analysis was restricted to primiparae, there was no statistically significant correlation between birth weight and the concentrations of PCDDs/PCDFs. No correlation was found between the weight of the child and PCBs, PCB-TEQs, or individual PCB congeners in the whole material or among primiparae, or among boys or girls. The concentrations of PCDDs/PCDFs and PCBs inhuman milk were modeled for primiparae by weighing fish consumption, age of mother, milk fat content, and BMI before pregnancy. The linear regression resulted in values of R = 0.67 and 0.30 for the modeled dioxin I-TEQs in the urban and rural areas, respectively, and the corresponding values for sumPCBs of R = 0

  18. PCDDs, PCDFs and PCNs in products of microwave-assisted pyrolysis of woody biomass--Distribution among solid, liquid and gaseous phases and effects of material composition.

    PubMed

    Gao, Qiuju; Budarin, Vitaliy L; Cieplik, Mariusz; Gronnow, Mark; Jansson, Stina

    2016-02-01

    Microwave-assisted pyrolysis (MAP) of lignocellulosic biomass is a technique that could potentially be used to produce and upgrade renewable energy carriers. However, there is no available information about the formation of dioxins and other organic pollutants in MAP treatment of woody biomass. In this study, MAP experiments were conducted in lab-scale using virgin softwood, bark, and impregnated wood as feedstocks. The non-condensable gas, liquid (fractionated into aqueous and oil phases), and char fractions generated during pyrolysis were collected and analysed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and naphthalenes (PCNs). The concentrations of PCDDs, PCDFs and PCNs in the pyrolysis products ranged from 0.52 to 43.7 ng kg(-1). All investigated compound groups were most abundant in the oil fraction, accounting for up to 68% (w/w) of the total concentrations. The highest PCDD, PCDF and PCN concentrations were found from the pyrolysis of bark, which has relatively high contents of chlorine and mineral matter, followed by impregnated wood, which contains organic and metal-based preservatives. The homologue profiles of all three compound groups were dominated by the less chlorinated homologues. The homologue abundance decreased as the degree of chlorination increased. This trend was observed for all three feedstocks. PMID:26688256

  19. Multiple Lines of Evidence Risk Assessment of Terrestrial Passerines Exposed to PCDFs and PCDDs in the Tittabawassee River Floodplain, Midland, Michigan, USA

    PubMed Central

    Fredricks, Timothy B.; Giesy, John P.; Coefield, Sarah J.; Seston, Rita M.; Tazelaar, Dustin L.; Roark, Shaun A.; Kay, Denise P.; Newsted, John L.; Zwiernik, Matthew J.

    2011-01-01

    A site-specific multiple lines of evidence risk assessment was conducted for house wrens (Troglodytes aedon) and eastern bluebirds (Sialia sialis) along the Tittabawassee River downstream of Midland, Michigan, where concentrations of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) in flood-plain soils and sediments are greater compared to upstream areas and some of the greatest anywhere in the world. Lines of evidence supporting the population-level assessment endpoints included site-specific dietary- and tissue-based exposure assessments and population productivity measurements during breeding seasons 2005–2007. While a hazard assessment based on site-specific diets suggested that populations residing in the downstream floodplain had the potential to be affected, concentrations in eggs compared to appropriate toxicity reference values (TRVs) did not predict a potential for population-level effects. There were no significant effects on reproductive success of either species. The most probable cause of the apparent difference between the dietary- and tissue-based exposure assessments was that the dietary-based TRVs were overly conservative based on intraperitoneal injections in the ring-necked pheasant. Agreement between the risk assessment based on concentrations of PCDFs and PCDDs in eggs and reproductive performance in both species supports the conclusion of a small potential for population-level effects at this site. PMID:21804755

  20. Artificial-turf playing fields: contents of metals, PAHs, PCBs, PCDDs and PCDFs, inhalation exposure to PAHs and related preliminary risk assessment.

    PubMed

    Menichini, Edoardo; Abate, Vittorio; Attias, Leonello; De Luca, Silvia; di Domenico, Alessandro; Fochi, Igor; Forte, Giovanni; Iacovella, Nicola; Iamiceli, Anna Laura; Izzo, Paolo; Merli, Franco; Bocca, Beatrice

    2011-11-01

    The artificial-turf granulates made from recycled rubber waste are of health concern due the possible exposure of users to dangerous substances present in the rubber, and especially to PAHs. In this work, we determined the contents of PAHs, metals, non-dioxin-like PCBs (NDL-PCBs), PCDDs and PCDFs in granulates, and PAH concentrations in air during the use of the field. The purposes were to identify some potential chemical risks and to roughly assess the risk associated with inhalation exposure to PAHs. Rubber granulates were collected from 13 Italian fields and analysed for 25 metals and nine PAHs. One further granulate was analysed for NDL-PCBs, PCDDs, PCDFs and 13 PAHs. Air samples were collected on filter at two fields, using respectively a high volume static sampler close to the athletes and personal samplers worn by the athletes, and at background locations outside the fields. In the absence of specific quality standards, we evaluated the measured contents with respect to the Italian standards for soils to be reclaimed as green areas. Zn concentrations (1 to 19 g/kg) and BaP concentrations (0.02 to 11 mg/kg) in granulates largely exceeded the pertinent standards, up to two orders of magnitude. No association between the origin of the recycled rubber and the contents of PAHs and metals was observed. The sums of NDL-PCBs and WHO-TE PCDDs+PCDFs were, respectively, 0.18 and 0.67×10(-5) mg/kg. The increased BaP concentrations in air, due to the use of the field, varied approximately from <0.01 to 0.4 ng/m(3), the latter referring to worst-case conditions as to the release of particle-bound PAHs. Based on the 0.4 ng/m(3) concentration, an excess lifetime cancer risk of 1×10(-6) was calculated for an intense 30-year activity. PMID:21907387

  1. PCDDs, PCDFs, PCBs, OC pesticides and mercury in fish and osprey eggs from Willamette River, Oregon (1993, 2001 and 2006) with calculated biomagnification factors.

    PubMed

    Henny, Charles J; Kaiser, James L; Grove, Robert A

    2009-02-01

    The osprey (Pandion haliaetus) population nesting along the main stem Willamette River and lower Santiam River was first studied to evaluate contaminants and reproductive rates in 1993 when 78 occupied nests were present. By 2001, the population increased to 234 occupied nests, a 13.7% annual rate of population increase. A sample egg was collected from each of a series of nests along the Upper River (river mile 55-187) in 1993, 2001 and 2006 to evaluate trends of persistent contaminants (organochlorine [OC] pesticides, polychlorinated biphenyls [PCBs], polychlorinated dibenzo-p-dioxins [PCDDs], and polychlorinated dibenzofurans [PCDFs]). Nearly all OC pesticide residues decreased significantly, e.g., p, p'-DDE (DDE) from 2,350 to 1,353 to 210 microg/kg wet weight (ww). PCBs followed a similar pattern over time, e.g., SigmaPCBs 688 to 245 to 182 microg/kg ww, while PCDDs and PCDFs showed a more precipitous decline (often 85-95%) between 1993 and 2001, with no egg analyses warranted in 2006. During 2001-2002, sample osprey eggs were also collected from nests at three Headwater Reservoirs and two lower reaches (Newberg Pool and Tidal Portland) of the Willamette River, as well as the lower portion of the Santiam River to evaluate spatial residue patterns. Significant differences were seldom detected among the different sampling areas for OC pesticides (probably due to small sample sizes), although higher concentrations were often seen in the lower reaches, e.g., DDE 901 microg/kg ww (Headwater Reservoirs), 1,353 (Upper River), 1,384 (Newberg Pool) and 2,676 (Tidal Portland). PCB congener concentrations in eggs were usually higher in the Tidal Portland reach than at other locations and often significantly higher than at the Headwater Reservoirs or Upper River. Mercury (first analyzed in eggs in 2001), PCDDs and PCDFs were extremely low in 2001/2002 with no significant spatial patterns. Whole fish composite samples of largescale sucker (Catastomus macrocheilus) and

  2. PCDDs, PCDFs, PCBs, OC pesticides and mercury in fish and osprey eggs from Willamette River, Oregon (1993, 2001 and 2006) with calculated biomagnification factors

    USGS Publications Warehouse

    Henny, C.J.; Kaiser, J.L.; Grove, R.A.

    2009-01-01

    The osprey (Pandion haliaetus) population nesting along the main stem Willamette River and lower Santiam River was first studied to evaluate contaminants and reproductive rates in 1993 when 78 occupied nests were present. By 2001, the population increased to 234 occupied nests, a 13.7% annual rate of population increase. A sample egg was collected from each of a series of nests along the Upper River (river mile 55-187) in 1993, 2001 and 2006 to evaluate trends of persistent contaminants (organochlorine [OC] pesticides, polychlorinated biphenyls [PCBs], polychlorinated dibenzo-p-dioxins [PCDDs], and polychlorinated dibenzofurans [PCDFs]). Nearly all OC pesticide residues decreased significantly, e.g., p, p?-DDE (DDE) from 2,350 to 1,353 to 210 ??g/kg wet weight (ww). PCBs followed a similar pattern over time, e.g., ???PCBs 688 to 245 to 182 ??g/kg ww, while PCDDs and PCDFs showed a more precipitous decline (often 85-95%) between 1993 and 2001, with no egg analyses warranted in 2006. During 2001-2002, sample osprey eggs were also collected from nests at three Headwater Reservoirs and two lower reaches (Newberg Pool and Tidal Portland) of the Willamette River, as well as the lower portion of the Santiam River to evaluate spatial residue patterns. Significant differences were seldom detected among the different sampling areas for OC pesticides (probably due to small sample sizes), although higher concentrations were often seen in the lower reaches, e.g., DDE 901 ??g/kg ww (Headwater Reservoirs), 1,353 (Upper River), 1,384 (Newberg Pool) and 2,676 (Tidal Portland). PCB congener concentrations in eggs were usually higher in the Tidal Portland reach than at other locations and often significantly higher than at the Headwater Reservoirs or Upper River. Mercury (first analyzed in eggs in 2001), PCDDs and PCDFs were extremely low in 2001/2002 with no significant spatial patterns. Whole fish composite samples of largescale sucker (Catastomus macrocheilus) and northern

  3. Ambient air concentrations of PCDDs, PCDFs, coplanar PCBs, and PAHs at the Mississippi Sandhill Crane National Wildlife Refuge, Jackson County, Mississippi

    USGS Publications Warehouse

    White, D.H.; Hardy, J.W.

    1994-01-01

    Our objective was to determine the levels of selected airborne contaminants in ambient air at the Mississippi Sandhill Crane National Wildlife Refuge, Mississippi, that might be affecting the health of endangered cranes living there. Two high-volume air samplers were operated at separate locations on the Refuge during May?September 1991. The sampling media were micro-quartz filters in combination with polyurethane foam plugs. Composite bimonthly samples from each station were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), coplanar polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). Overall, residue concentrations were low. The toxic PCDD isomer 2,3,7,8-tetra-CDD was not detected, nor was penta-CDD. There was no difference (P>0.05) in residue concentrations between stations or over time and meteorological parameters were not correlated with residue concentrations. Because contaminant levels and patterns may differ seasonally, we recommend that air samples collected during winter months also be analyzed for these same chemical groups.

  4. Contamination status and accumulation features of PCDDs, PCDFs and dioxin-like PCBs in finless porpoises (Neophocaena phocaenoides) from Korean coastal waters.

    PubMed

    Moon, Hyo-Bang; Choi, Hee-Gu; An, Yong-Rock; Park, Kyum Joon; Choi, Seok-Gwan; Moon, Dae-Yeon; Kannan, Kurunthachalam

    2010-11-15

    Data on the concentrations and accumulation profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in cetaceans are scarce. In this study, concentrations and accumulation profiles of PCDD/Fs and DL-PCBs were measured in the blubber of finless porpoises (Neophocaena phocaenoides) collected from Korean coastal waters. Total dioxin-like toxic equivalent (TEQ) concentrations (6.5-31 pg/g lipid weight) in finless porpoises were lower than those reported for cetaceans and pinnipeds from other countries. Significant gender-specific differences were found in the concentrations and accumulation profiles of PCDD/Fs and DL-PCBs and this difference was associated with maternal and lactation transfer of contaminants from mature females to their fetus. All of the PCDD/F homologue groups were detected in all of the samples and the proportions of PCDFs were higher than those of PCDDs. The dominant congeners found in finless porpoise blubber were 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF and OCDD for PCDD/Fs and PCB 118 for DL-PCBs. The accumulation profiles of PCDD/Fs in finless porpoise in our study were different from those found for cetaceans from other countries. Total TEQ levels in finless porpoises in Korea were below the suggested threshold values for adverse health effects in marine mammals. PMID:20724068

  5. Biomagnification factors (fish to Osprey eggs from Willamette River, Oregon, U.S.A.) for PCDDs, PCDFs, PCBs and OC pesticides.

    PubMed

    Henny, Charles J; Kaiser, James L; Grove, Robert A; Bentley, V Raymond; Elliott, John E

    2003-06-01

    A migratory population of 78 pairs of Osprey (Pandion haliaetus) nesting along the Willamette River in western Oregon was studied in 1993. The study was designed to determine contaminant concentrations in eggs, contaminant concentrations in fish species predominant in the Ospreys diet, and Biomagnification Factors (BMFs) of contaminants from fish species eaten to Osprey eggs. Ten Osprey eggs and 25 composite samples of fish (3 species) were used to evaluate organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). Mercury was also analyzed in fish. Geometric mean residues in Osprey eggs were judged low, e.g., DDE 2.3 microg g(-1) wet weight (ww), sigma PCBs 0.69 microg g(-1), 2,3,7,8-TCDD 2.3 ng kg(-1), and generally well below known threshold values for adverse effects on productivity, and the population was increasing. Osprey egg residue data presented by River Mile (RM) are discussed, e.g., higher PCDDs were generally found immediately downstream of paper mills and eggs from the Willamette River had significantly elevated PCBs and PCDDs compared to reference eggs collected nearby in the Cascade Mountains. Prey remains at nest sites indicated that the Largescale Sucker (Catostomus macrocheilus) and Northern Pikeminnow (Ptychocheilus oregonensis) accounted for an estimated 90.1% of the biomass in the Osprey diet, and composite samples of these two species were collected from different sampling sites throughout the study area for contaminant analyses. With the large percentage of the fish biomass in the Osprey diet sampled for contaminants (and fish eaten by Ospreys similar in size to those chemically analyzed), and fish contaminant concentrations weighted by biomass intake, a mean BMF was estimated from fish to Osprey eggs for the large series of contaminants. BMFs ranged from no biomagnification (0.42) for 2,3,7,8-TCDF to 174 for OCDD. Our findings for the migratory

  6. Biomagnification factors (fish to osprey eggs from Willamette River, Oregon, U.S.A.) for PCDDS, PCDFS, PCBS, and OC pesticides

    USGS Publications Warehouse

    Henny, Charles J.; Kaiser, James L.; Grove, Robert A.; Bentley, V.R.; Elliot, J.E.

    2003-01-01

    A migratory population of 78 pairs of Osprey (Pandion haliaetus) nesting along the Willamette River in westernOregon was studied in 1993. The study was designed to determinecontaminant concentrations in eggs, contaminant concentrationsin fish species predominant in the Ospreys diet, andBiomagnification Factors (BMFs) of contaminants from fish specieseaten to Osprey eggs. Ten Osprey eggs and 25 composite samplesof fish (3 species) were used to evaluate organochlorine (OC)pesticides, polychlorinated biphenyls (PCBs), polychlorinateddibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans(PCDFs). Mercury was also analyzed in fish. Geometric meanresidues in Osprey eggs were judged low, e.g., DDE 2.3 g g-1 wet weight (ww), PCBs 0.69 g g-1, 2,3,7,8-TCDD 2.3 ng kg-1, and generally well below known threshold values for adverse effects on productivity, and the population was increasing. Osprey egg residue data presentedby River Mile (RM) are discussed, e.g., higher PCDDs were generally found immediately downstream of paper mills and eggsfrom the Willamette River had significantly elevated PCBs and PCDDs compared to reference eggs collected nearby in the CascadeMountains. Prey remains at nest sites indicated that the Largescale Sucker (Catostomus macrocheilus) and NorthernPikeminnow (Ptychocheilus oregonensis) accounted for an estimated 90.1% of the biomass in the Osprey diet, and composite samples of these two species were collected from different sampling sites throughout the study area for contaminant analyses. With the large percentage of the fishbiomass in the Osprey diet sampled for contaminants (and fisheaten by Ospreys similar in size to those chemically analyzed),and fish contaminant concentrations weighted by biomass intake, a mean BMF was estimated from fish to Osprey eggs for the largeseries of contaminants. BMFs ranged from no biomagnification(0.42) for 2,3,7,8-TCDF to 174 for OCDD. Our findings for themigratory Osprey were compared to BMFs for the resident

  7. Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in breast milk of first-time Irish mothers: impact of the 2008 dioxin incident in Ireland.

    PubMed

    Pratt, Iona S; Anderson, Wayne A; Crowley, Dominique; Daly, Sean F; Evans, Rhodri I; Fernandes, Alwyn R; Fitzgerald, Margaret; Geary, Michael P; Keane, Declan P; Malisch, Rainer; McBride, John; Morrison, John J; Reilly, Alan; Tlustos, Christina

    2012-08-01

    The 2008 dioxin incident in Ireland resulted in elevated concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in Irish pork and pork products, due to the consumption of contaminated animal feed by pigs. In order to investigate any resulting impact on the Irish population, these contaminants were measured in pooled breast milk samples from 109 first-time mothers, collected in 2010. A comparison of the results with similar data from 2002 revealed generally lower concentrations of PCDD/Fs and dioxin-like PCBs in the 2010 samples, confirming the declining trend reported by many authors. Contaminant concentration levels for both 2002 and 2010 were generally slightly lower than those reported internationally, with a mean combined PCDD/F and PCB WHO-TEQ of 9.66pgg(-1)fat, for an overall pooled sample of milk from 2010. An apparent slight increase in PCDFs was observed between 2002 and 2010 (from 2.73pg WHO-TEQ g(-1)fat to 3.21pg WHO-TEQ g(-1)fat), with the main contributory congener being 2,3,4,7,8-PentaCDF. While it cannot be totally discounted that the slight increase in 2,3,4,7,8-PentaCDF and in the overall PCDF WHO-TEQ in breast milk could be attributable to consumption of Irish pork during the 2008 incident, we consider that it is more likely that this was due to other factors, including the predominantly urban/industrial sampling locations for the 2010 samples, compared to 2002. PMID:22560976

  8. Exposure to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (DL-PCBs) and polybrominated diphenyl ethers (PBDEs) through the consumption of prepared meals in Italy.

    PubMed

    De Filippis, Stefania P; Brambilla, Gianfranco; Dellatte, Elena; Corrado, Federica; Esposito, Mauro

    2014-01-01

    Diet is a relevant source of exposure to environmental pollutants. Dietary intake of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (DL-PCBs) and polybrominated diphenyl ethers (PBDEs) by the Italian population was assessed through a duplicate diet study on prepared meals. Baby food composite representative of the diet of toddlers aged 9-12 months and school canteen servings from four towns in Italy representing the diet of children aged 4-9 years were collected on a 5-day basis. Similarly, 5-day lunches from an office canteen, 7-day lunches from a hotel-school, three fast food meals, and eight duplicate 1-day meals of individuals (one vegetarian) were selected to represent the diet of adults aged above 18 years. Servings from each diet were then pooled to form a composite and analysed. Dietary intake was estimated from the resulting contaminant levels in composites combined with age-related food consumption data from national survey. The mean upper bound (UB) intakes for cumulative PCDDs, PCDFs, and DL-PCBs were 0.67, 0.63-0.92, and 0.27-0.63 pg WHO2005-TE kg(-1) body weight (bw) day(-1) for toddlers, children and adults, respectively. BDE-47 (UB) ng kg(-1) bw day(-1) estimates were 2.75 in toddlers, 0.08-0.16 in children and 0.03-0.09 in adults. Similarly, for BDE-99 higher UB intakes (ng kg(-1) bw day(-1)) resulted in toddlers (1.26), than those in children (0.06-0.08) and adults (0.03-0.10), respectively. The above estimates fall below the tolerable weekly intake (TWI) (14 WHO2005-TE kg(-1) bw day(-1)) established by the European Union Scientific Committee on Food (SCF) for PCDD/Fs and DL-PCBs. The margin of exposure (MOE = 3) of toddlers to BDE-99 clearly indicates this age group as target for a risk-oriented approach. This study is proposed as a first cost-effective screening in PCDD, PCDF, DL-PCB and PBDE intake assessment, with a focus also on time trends. PMID:24645918

  9. Multiple lines of evidence risk assessment of American robins exposed to polychlorinated dibenzofurans (PCDFS) and polychlorinated dibenzo-P-dioxins (PCDDS) in the Tittabawassee River floodplain, Midland, Michigan, USA.

    PubMed

    Tazelaar, Dustin L; Fredricks, Timothy B; Seston, Rita M; Coefield, Sarah J; Bradley, Patrick W; Roark, Shaun A; Kay, Denise P; Newsted, John L; Giesy, John P; Bursian, Steven J; Zwiernik, Matthew J

    2013-06-01

    Concentrations of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) in Tittabawassee River floodplain soils and biota downstream of Midland, Michigan, USA, are greater than regional background concentrations. From 2005 to 2008, a multiple lines of evidence approach was utilized to evaluate the potential for effects of PCDD/DFs on American robins (Turdus migratorius) breeding in the floodplains. A dietary-based assessment indicated there was potential for adverse effects for American robins predicted to have the greatest exposures. Conversely, a tissue-based risk assessment based on site-specific PCDD/DF concentrations in American robin eggs indicated minimal potential for adverse effects. An assessment based on reproductive endpoints indicated that measures of hatch success in study areas were significantly less than those of reference areas. However, there was no dose-response relationship between that endpoint and concentrations of PCDD/DF. Although dietary-based exposure and reproductive endpoint assessments predicted potential for adverse effects to resident American robins, the tissue-based assessment indicates minimal to no potential for adverse effects, which is reinforced by the fact the response was not dose related. It is likely that the dietary assessment is overly conservative given the inherent uncertainties of estimating dietary exposure relative to direct tissue-based assessment measures. Based on the available data, it can be concluded that exposure to PCDD/DFs in the Tittabawassee River floodplain would not likely result in adverse population-level effects to American robins. PMID:23424046

  10. Relationships between dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like biphenyls (dl-PCBs) congener concentrations in aquatic organisms from Sydney Estuary, Australia and physiology, spatial, seasonality, trophodynamic and life history traits.

    PubMed

    Sezmis, Aysha Laila; Birch, Gavin; Covaci, Adrian

    2014-08-15

    Over the past few decades, there has been considerable interest in hydrophobic persistent organic pollutants (POPs) and their accumulative properties in aquatic organisms. Several factors, such as environmental concentrations (i.e. in sediment) and physiological characteristics of organisms determine species-specific accumulation patterns of POPs in marine animal tissue. The present study investigated factors that govern species-specific accumulation patterns of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like biphenyls (dl-PCBs) in a food web from Sydney Estuary (Australia). The results indicated that physiological characteristics, i.e. lipid %, spatial, i.e. distance from Homebush Bay (point source of POPs) and life history characteristics of the organisms, such as diet and home range, influence PCDD/F and dl-PCB tissue concentrations to a varying degree. For example, PCDD/F tissue concentrations increased with the presence of detritivorous diet, species with limited home range and close proximity to Homebush Bay. On the other hand, lipid %, piscivorous diet and close proximity to Homebush Bay were the main predictors causing increases in dl-PCB tissue levels. Distance from Homebush Bay was the only predictor affecting both PCDD/F and dl-PCB tissue levels at a similar rate, i.e. decreasing tissue concentrations as the distance increases from Homebush Bay. PMID:24840280

  11. Portable exhausters POR-004 SKID B, POR-005 SKID C, POR-006 SKID D storage plan

    SciTech Connect

    Nelson, O.D.

    1997-09-04

    This document provides a storage plan for portable exhausters POR-004 SKID B, POR-005 SKID C, AND POR-006 SKID D. The exhausters will be stored until they are needed by the TWRS (Tank Waste Remediation Systems) Saltwell Pumping Program. The storage plan provides criteria for portable exhauster storage, periodic inspections during storage, and retrieval from storage.

  12. Evolution of NADPH-cytochrome P450 oxidoreductases (POR) in Apiales - POR 1 is missing.

    PubMed

    Andersen, Trine Bundgaard; Hansen, Niels Bjørn; Laursen, Tomas; Weitzel, Corinna; Simonsen, Henrik Toft

    2016-05-01

    The NADPH-dependent cytochrome P450 oxidoreductase (POR) is the obligate electron donor to eukaryotic microsomal cytochromes P450 enzymes. The number of PORs within plant species is limited to one to four isoforms, with the most common being two PORs per plant. These enzymes provide electrons to a huge number of different cytochromes P450s (from 50 to several hundred within one plant). Within the eudicotyledons, PORs can be divided into two major clades, POR 1 and POR 2. Based on our own sequencing analysis and publicly available data, we have identified 45 PORs from the angiosperm order Apiales. These were subjected to a phylogenetic analysis along with 237 other publicly available (NCBI and oneKP) POR sequences found within the clade Asterids. Here, we show that the order Apiales only harbor members of the POR 2 clade, which are further divided into two distinct subclades. This is in contrast to most other eudicotyledon orders that have both POR 1 and POR 2. This suggests that through gene duplications and one gene deletion, Apiales only contain members of the POR 2 clade. Three POR 2 isoforms from Thapsia garganica L., Apiaceae, were all full-length in an Illumina root transcriptome dataset (available from the SRA at NCBI). All three genes were shown to be functional upon reconstitution into nanodiscs, confirming that none of the isoforms are pseudogenes. PMID:26854662

  13. Portable exhauster POR-007/Skid E and POR-008/Skid F storage plan

    SciTech Connect

    Nelson, O.D.

    1998-07-25

    This document provides storage requirements for 1,000 CFM portable exhausters POR-O07/Skid E and POR-008/Skid F. These requirements are presented in three parts: preparation for storage, storage maintenance and testing, and retrieval from storage. The exhauster component identification numbers listed in this document contain the prefix POR-007 or POR-008 depending on which exhauster is being used.

  14. Consequences of POR mutations and polymorphisms.

    PubMed

    Miller, Walter L; Agrawal, Vishal; Sandee, Duanpen; Tee, Meng Kian; Huang, Ningwu; Choi, Ji Ha; Morrissey, Kari; Giacomini, Kathleen M

    2011-04-10

    P450 oxidoreductase (POR) transports electrons from NADPH to all microsomal cytochrome P450 enzymes, including steroidogenic P450c17, P450c21 and P450aro. Severe POR mutations A287P (in Europeans) and R457H (in Japanese) cause the Antley-Bixler skeletal malformation syndrome (ABS) plus impaired steroidogenesis (causing genital anomalies), but the basis of ABS is unclear. We have characterized the activities of ∼40 POR variants, showing that assays based on P450c17 activities, but not cytochrome c assays, correlate with the clinical phenotype. The human POR gene is highly polymorphic: the A503V sequence variant, which decreases P450c17 activities to ∼60%, is found on ∼28% of human alleles. A promoter polymorphism (∼8% of Asians and ∼13% of Caucasians) at -152 reduces transcriptional activity by half. Screening of 35 POR variants showed that most mutants lacking activity with P450c17 or cytochrome c also lacked activity to support CYP1A2 and CYP2C19 metabolism of EOMCC (a fluorogenic non-drug substrate), although there were some remarkable differences: Q153R causes ABS and has ∼30% of wild-type activity with P450c17 but had 144% of WT activity with CYP1A2 and 284% with CYP2C19. The effects of POR variants on CYP3A4, which metabolizes nearly 50% of clinically used drugs, was examined with multiple, clinically relevant drug substrates, showing that A287P and R457H dramatically reduce drug metabolism, and that A503V variably impairs drug metabolism. The degree of activity can vary with the drug substrate assayed, as the drugs can influence the conformation of the P450. POR is probably an important contributor to genetic variation in both steroidogenesis and drug metabolism. PMID:21070833

  15. Consequences of POR mutations and polymorphisms

    PubMed Central

    Miller, Walter L.; Agrawal, Vishal; Sandee, Duanpen; Tee, Meng Kian; Huang, Ningwu; Choi, Ji Ha; Morrissey, Kari; Giacomini, Kathleen M.

    2015-01-01

    P450 oxidoreductase (POR) transports electrons from NADPH to all microsomal cytochrome P450 enzymes, including steroidogenic P450c17, P450c21 and P450aro. Severe POR mutations A287P (in Europeans) and R457H (in Japanese) cause the Antley-Bixler skeletal malformation syndrome (ABS) plus impaired steroidogenesis (causing genital anomalies), but the basis of ABS is unclear. We have characterized the activities of ~40 POR variants, showing that assays based on P450c17 activities, but not cytochrome c assays, correlate with the clinical phenotype. The human POR gene is highly polymorphic: the A503V sequence variant, which decreases P450c17 activities to ~60%, is found on ~28% of human alleles. A promoter polymorphism (~8% of Asians and ~13% of Caucasians) at −152 reduces transcriptional activity by half. Screening of 35 POR variants showed that most mutants lacking activity with P450c17 or cytochrome c also lacked activity to support CYP1A2 and CYP2C19 metabolism of EOMCC (a fluorogenic non-drug substrate), although there were some remarkable differences: Q153R causes ABS and has ~30% of wild-type activity with P450c17 but had 144% of WT activity with CYP1A2 and 284% with CYP2C19. The effects of POR variants on CYP3A4, which metabolizes nearly 50% of clinically used drugs, was examined with multiple, clinically-relevant drug substrates, showing that A287P and R457H dramatically reduce drug metabolism, and that A503V variably impairs drug metabolism. The degree of activity can vary with the drug substrate assayed, as the drugs can influence the conformation of the P450. POR is probably an important contributor to genetic variation in both steroidogenesis and drug metabolism. PMID:21070833

  16. Desigualdades por cáncer

    Cancer.gov

    Información básica de las desigualdades en salud por cáncer en EE. UU., factores que contribuyen a la carga desproporcionada del cáncer en algunos grupos y ejemplos de desigualdades en incidencia y mortalidad entre ciertos grupos de la población.

  17. Structural Insights into the PorK and PorN Components of the Porphyromonas gingivalis Type IX Secretion System

    PubMed Central

    Gorasia, Dhana G.; Veith, Paul D.; Hanssen, Eric G.; Glew, Michelle D.; Sato, Keiko; Yukitake, Hideharu; Nakayama, Koji; Reynolds, Eric C.

    2016-01-01

    The type IX secretion system (T9SS) has been recently discovered and is specific to Bacteroidetes species. Porphyromonas gingivalis, a keystone pathogen for periodontitis, utilizes the T9SS to transport many proteins including the gingipain virulence factors across the outer membrane and attach them to the cell surface via a sortase-like mechanism. At least 11 proteins have been identified as components of the T9SS including PorK, PorL, PorM, PorN and PorP, however the precise roles of most of these proteins have not been elucidated and the structural organization of these components is unknown. In this study, we purified PorK and PorN complexes from P. gingivalis and using electron microscopy we have shown that PorN and the PorK lipoprotein interact to form a 50 nm diameter ring-shaped structure containing approximately 32–36 subunits of each protein. The formation of these rings was dependent on both PorK and PorN, but was independent of PorL, PorM and PorP. PorL and PorM were found to form a separate stable complex. PorK and PorN were protected from proteinase K cleavage when present in undisrupted cells, but were rapidly degraded when the cells were lysed, which together with bioinformatic analyses suggests that these proteins are exposed in the periplasm and anchored to the outer membrane via the PorK lipid. Chemical cross-linking and mass spectrometry analyses confirmed the interaction between PorK and PorN and further revealed that they interact with the PG0189 outer membrane protein. Furthermore, we established that PorN was required for the stable expression of PorK, PorL and PorM. Collectively, these results suggest that the ring-shaped PorK/N complex may form part of the secretion channel of the T9SS. This is the first report showing the structural organization of any T9SS component. PMID:27509186

  18. Structural Insights into the PorK and PorN Components of the Porphyromonas gingivalis Type IX Secretion System.

    PubMed

    Gorasia, Dhana G; Veith, Paul D; Hanssen, Eric G; Glew, Michelle D; Sato, Keiko; Yukitake, Hideharu; Nakayama, Koji; Reynolds, Eric C

    2016-08-01

    The type IX secretion system (T9SS) has been recently discovered and is specific to Bacteroidetes species. Porphyromonas gingivalis, a keystone pathogen for periodontitis, utilizes the T9SS to transport many proteins including the gingipain virulence factors across the outer membrane and attach them to the cell surface via a sortase-like mechanism. At least 11 proteins have been identified as components of the T9SS including PorK, PorL, PorM, PorN and PorP, however the precise roles of most of these proteins have not been elucidated and the structural organization of these components is unknown. In this study, we purified PorK and PorN complexes from P. gingivalis and using electron microscopy we have shown that PorN and the PorK lipoprotein interact to form a 50 nm diameter ring-shaped structure containing approximately 32-36 subunits of each protein. The formation of these rings was dependent on both PorK and PorN, but was independent of PorL, PorM and PorP. PorL and PorM were found to form a separate stable complex. PorK and PorN were protected from proteinase K cleavage when present in undisrupted cells, but were rapidly degraded when the cells were lysed, which together with bioinformatic analyses suggests that these proteins are exposed in the periplasm and anchored to the outer membrane via the PorK lipid. Chemical cross-linking and mass spectrometry analyses confirmed the interaction between PorK and PorN and further revealed that they interact with the PG0189 outer membrane protein. Furthermore, we established that PorN was required for the stable expression of PorK, PorL and PorM. Collectively, these results suggest that the ring-shaped PorK/N complex may form part of the secretion channel of the T9SS. This is the first report showing the structural organization of any T9SS component. PMID:27509186

  19. The PorX Response Regulator of the Porphyromonas gingivalis PorXY Two-Component System Does Not Directly Regulate the Type IX Secretion Genes but Binds the PorL Subunit

    PubMed Central

    Vincent, Maxence S.; Durand, Eric; Cascales, Eric

    2016-01-01

    The Type IX secretion system (T9SS) is a versatile multi-protein complex restricted to bacteria of the Bacteriodetes phylum and responsible for the secretion or cell surface exposition of diverse proteins that participate to S-layer formation, gliding motility or pathogenesis. The T9SS is poorly characterized but a number of proteins involved in the assembly of the secretion apparatus in the oral pathogen Porphyromonas gingivalis have been identified based on genome substractive analyses. Among these proteins, PorY, and PorX encode typical two-component system (TCS) sensor and CheY-like response regulator respectively. Although the porX and porY genes do not localize at the same genetic locus, it has been proposed that PorXY form a bona fide TCS. Deletion of porX in P. gingivalis causes a slight decrease of the expression of a number of other T9SS genes, including sov, porT, porP, porK, porL, porM, porN, and porY. Here, we show that PorX and the soluble cytoplasmic domain of PorY interact. Using electrophoretic mobility shift, DNA-protein co-purification and heterologous host expression assays, we demonstrate that PorX does not bind T9SS gene promoters and does not directly regulate expression of the T9SS genes. Finally, we show that PorX interacts with the cytoplasmic domain of PorL, a component of the T9SS membrane core complex and propose that the CheY-like PorX protein might be involved in the dynamics of the T9SS.

  20. Identification of Porphyromonas gingivalis proteins secreted by the Por secretion system.

    PubMed

    Sato, Keiko; Yukitake, Hideharu; Narita, Yuka; Shoji, Mikio; Naito, Mariko; Nakayama, Koji

    2013-01-01

    The Gram-negative bacterium Porphyromonas gingivalis possesses a number of potential virulence factors for periodontopathogenicity. In particular, cysteine proteinases named gingipains are of interest given their abilities to degrade host proteins and process other virulence factors such as fimbriae. Gingipains are translocated on the cell surface or into the extracellular milieu by the Por secretion system (PorSS), which consists of a number of membrane or periplasmic proteins including PorK, PorL, PorM, PorN, PorO, PorP, PorQ, PorT, PorU, PorV (PG27, LptO), PorW and Sov. To identify proteins other than gingipains secreted by the PorSS, we compared the proteomes of P. gingivalis strains kgp rgpA rgpB (PorSS-proficient strain) and kgp rgpA rgpB porK (PorSS-deficient strain) using two-dimensional gel electrophoresis and peptide-mass fingerprinting. Sixteen spots representing 10 different proteins were present in the particle-free culture supernatant of the PorSS-proficient strain but were absent or faint in that of the PorSS-deficient strain. These identified proteins possessed the C-terminal domains (CTDs), which had been suggested to form the CTD protein family. These results indicate that the PorSS is used for secretion of a number of proteins other than gingipains and that the CTDs of the proteins are associated with the PorSS-dependent secretion. PMID:23075153

  1. System design description for portable 1,000 CFM exhauster Skids POR-007/Skid E and POR-008/Skid F

    SciTech Connect

    Nelson, O.D.

    1998-07-25

    The primary purpose of the two 1,000 CFM Exhauster Skids, POR-007-SKID E and POR-008-SKID F, is to provide backup to the waste tank primary ventilation systems for tanks 241-C-106 and 241-AY-102, and the AY-102 annulus in the event of a failure during the sluicing of tank 241-C-106 and subsequent transfer of sluiced waste to 241-AY-102. This redundancy is required since both of the tank ventilation systems have been declared as Safety Class systems.

  2. Disminuyen en los Estados Unidos las infecciones por VPH.

    Cancer.gov

    La infección por los tipos del virus del papiloma humano (VPH) en el blanco de la vacuna cuadrivalente se redujo en casi dos tercios en las adolescentes desde que se recomendó la vacunación en los Estados Unidos.

  3. Centros oncológicos designados por el NCI

    Cancer.gov

    El programa de centros oncológicos designados por el Instituto Nacional del Cáncer (NCI) reconoce a los centros de todo el país que cumplen con rigurosos criterios para participar en proyectos avanzados de primer nivel para la investigación multidisciplinaria del cáncer.

  4. Se evitaron casi 800 000 muertes por descenso del tabaquismo

    Cancer.gov

    Programas y estrategias de control del tabaco del siglo XX fueron responsables de la prevención de más de 795 000 muertes por cáncer de pulmón en Estados Unidos de 1975 al 2000. Si todo el tabaquismo en este país hubiera cesado después de la publicación d

  5. Neisseria meningitidis Lacking the Major Porins PorA and PorB Is Viable and Modulates Apoptosis and the Oxidative Burst of Neutrophils.

    PubMed

    Peak, Ian R; Chen, Adrienne; Jen, Freda E-C; Jennings, Courtney; Schulz, Benjamin L; Saunders, Nigel J; Khan, Arshad; Seifert, H Steven; Jennings, Michael P

    2016-08-01

    The bacterial pathogen Neisseria meningitidis expresses two major outer-membrane porins. PorA expression is subject to phase-variation (high frequency, random, on-off switching), and both PorA and PorB are antigenically variable between strains. PorA expression is variable and not correlated with meningococcal colonisation or invasive disease, whereas all naturally-occurring strains express PorB suggesting strong selection for expression. We have generated N. meningitidis strains lacking expression of both major porins, demonstrating that they are dispensable for bacterial growth in vitro. The porAB mutant strain has an exponential growth rate similar to the parental strain, as do the single porA or porB mutants, but the porAB mutant strain does not reach the same cell density in stationary phase. Proteomic analysis suggests that the double mutant strain exhibits compensatory expression changes in proteins associated with cellular redox state, energy/nutrient metabolism, and membrane stability. On solid media, there is obvious growth impairment that is rescued by addition of blood or serum from mammalian species, particularly heme. These porin mutants are not impaired in their capacity to inhibit both staurosporine-induced apoptosis and a phorbol 12-myristate 13-acetate-induced oxidative burst in human neutrophils suggesting that the porins are not the only bacterial factors that can modulate these processes in host cells. PMID:26562068

  6. Compton imaging with the PorGamRays spectrometer

    NASA Astrophysics Data System (ADS)

    Judson, D. S.; Boston, A. J.; Coleman-Smith, P. J.; Cullen, D. M.; Hardie, A.; Harkness, L. J.; Jones, L. L.; Jones, M.; Lazarus, I.; Nolan, P. J.; Pucknell, V.; Rigby, S. V.; Seller, P.; Scraggs, D. P.; Simpson, J.; Slee, M.; Sweeney, A.; PorGamRays Collaboration

    2011-10-01

    The PorGamRays project aims to develop a portable gamma-ray detection system with both spectroscopic and imaging capabilities. The system is designed around a stack of thin Cadmium Zinc Telluride (CZT) detectors. The imaging capability utilises the Compton camera principle. Each detector is segmented into 100 pixels which are read out through custom designed Application Specific Integrated Circuits (ASICs). This device has potential applications in the security, decommissioning and medical fields. This work focuses on the near-field imaging performance of a lab-based demonstrator consisting of two pixelated CZT detectors, each of which is bonded to a NUCAM II ASIC. Measurements have been made with point 133Ba and 57Co sources located ˜35 mm from the surface of the scattering detector. Position resolution of ˜20 mm FWHM in the x and y planes is demonstrated.

  7. Acceptance test report for portable exhauster POR-007/Skid E

    SciTech Connect

    Kriskovich, J.R.

    1998-07-24

    This document describes Acceptance Testing performed on Portable Exhauster POR-007/Skid E. It includes measurements of bearing vibration levels, pressure decay testing, programmable logic controller interlocks, high vacuum, flow and pressure control functional testing. The purpose of Acceptance testing documented by this report was to demonstrate compliance of the exhausters with the performance criteria established within HNF-0490, Rev. 1 following a repair and upgrade effort at Hanford. In addition, data obtained during this testing is required for the resolution of outstanding Non-conformance Reports (NCR), and finally, to demonstrate the functionality of the associated software for the pressure control and high vacuum exhauster operating modes provided for by W-320. Additional testing not required by the ATP was also performed to assist in the disposition and close out of receiving inspection report and for application design information (system curve). Results of this testing are also captured within this document.

  8. Typing and surface charges of the variable loop regions of PorB from Neisseria meningitidis.

    PubMed

    Stefanelli, Paola; Neri, Arianna; Tanabe, Mikio; Fazio, Cecilia; Massari, Paola

    2016-06-01

    PorB is a pan-Neisserial major outer membrane protein with a trimeric β-barrel structure. Each monomer presents eight periplasmic turns and eight surface exposed loop regions with sequence variability. PorB induces activation of host cell responses via a TLR2-dependent mechanism likely mediated by electrostatic interactions between TLR2 and PorB surface exposed loops. Variability in the loop amino acid sequence is known to influence cell responses to PorB in vitro, particularly for the residues in L5 and L7. In this work, the sequence of the porB gene and the electrostatic surface charges of PorB from 35 invasive meningococcal isolates belonging to the main clonal complexes identified in Italy and from five carriage genomes available on the website http://pubmlst.org/neisseria/ were examined. Analysis of the porB encoding regions from the invasive meningococci has identified four new alleles and a potential association between porB alleles, serogroup, and clonal complexes. Through computer-based modeling and analysis of the electrostatic surface charges of PorB from these strains, loop charge segregation between PorB from invasive serogroups B and C was observed. Specifically, loops 1, 4, and 7 were negatively charged and L2 and L8 were mostly neutral in serogroup B isolates, while an overall homogeneous positive surface charge was present in PorB from invasive serogroup C strains. A higher PorB sequence variability was observed among carriage genomes, and a general prevalence of negative loop surface charges. The surface charge differences in PorB from serogroups B and C invasive and carriage strains may, in part, influence the outcomes of Neisseriae interactions with host cells. © 2016 IUBMB Life, 68(6):488-495, 2016. PMID:27156582

  9. Monitoring of PCDDs, PCDFs and PCBs in the Fraser River, British Columbia using SPMD

    SciTech Connect

    Ikonomou, M.G.; Fraser, T.L.; Rogers, I.H.; Rantalainen, A.L.

    1995-12-31

    Semipermeable membrane devices (SPMD) are sampling devices comprised of thin wall polyethylene tubing that encloses a thin film of lipid, triolein. SPMDs have been used successfully to monitor non-polar industrial pollutants from air, water, and sediments. Chemical contaminants dissolved in water dialyze into the lipid mimicking bioconcentration mechanisms in aquatic organisms. The authors have deployed SPMDs at several sites in the water column of the lower Fraser River and the Harisson River, a control site, to assess bioavailability and to determine sources of polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF), and mono-ortho and non-ortho substituted polychlorinated biphenyls (PCB). SPMD sampling was performed during similar time periods in the summers of 1992 and 1994. PCDDs/Fs and PCBs were extracted from the lipid of the SPMDs using in-house developed methodology and extracts were analyzed and quantitated by HRGC/HRMS. The analytical data were inter-compared for characteristic congener distribution patterns and concentration differences of prominent PCDD/Fs and PCBs congeners between sites and sampling years. River flow rates, as calculated from the IOS Ages/Woollard Fraser River model, were considered for the inter-site comparisons. Relative congener composition from each sample was similar from site to site within a sampling year. Overall levels of prominent contaminants, TCDF and PCB 118 and 105, dropped significantly from 1992 to 1994. Comparisons between the reference site and the Fraser river data differentiate between atmospheric and point source contamination of the river. PCDD/Fs and PCBs were detected in the tissues of two species of Fraser River resident fish, their relation to the SPMD data will be discussed.

  10. On-road emissions of PCDDs and PCDFs from heavy duty diesel vehicles.

    PubMed

    Gullett, Brian K; Ryan, Jeffrey V

    2002-07-01

    This work characterized emission factors of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs) from on-road sampling of three heavy duty diesel vehicles (HDDVs) under experimental conditions of city and highway driving; idling operation; high (>400 ppm) and low (<5 ppm) sulfur (S) fuels; and high mileage and rebuilt engine testing. Emission factors, homologue profiles, and isomer patterns were compared to determine whether the experimental conditions had an impact on PCDD/F emissions, or whether these conditions were uninfluential in determining a fleet-representative emission factor. For a single HDDV tested under conditions of a high mileage engine, a newly rebuilt engine, and the newly rebuilt engine with low S diesel fuel, emission factors were 0.023 (+/- 0.022), 0.008 (+/- 0.002), and 0.016 (+/- 0.013) ng toxic equivalency (TEQ)/km, respectively. These results may infer some limited condition-specific differences in PCDD/F emissions, but these differences do not appear to have a significant effect on the HDDV emission factor. An older HDDV with mechanical fuel controls resulted in a single test value of 0.164 ng TEQ/km, significantly higher than all other results. Observed differences in emission factors, homologue profiles, and TEQ-related isomer patterns from this on-vehicle sampling and others' tunnel sampling suggest limitations in our present characterization of fleet PCDD/F emissions. PMID:12144283

  11. Calcium-promoted catalytic degradation of PCDDs, PCDFs, and coplanar PCBs under a mild wet process.

    PubMed

    Mitoma, Yoshiharu; Tasaka, Norie; Takase, Maki; Masuda, Taizo; Tashiro, Hideki; Egashira, Naoyoshi; Oki, Takashi

    2006-03-15

    The authors achieved highly efficient degradation of polychlorinated aromatic compounds, including polychlorinated dibenzo-p-dioxins, dibenzofurans, and dioxin-like compounds such as coplanar polychlorinated biphenyls (co-PCBs), which are known as persistent organic pollutants. Degradation was accomplished in 24 h through a simple stirring operation using safe and high workability metallic calcium, which acts as both a scavenger and a reducing agent, and Rh/C catalyst in an alcohol solution under mild conditions in a sealed tube at 25 degrees C without a temperature increase within 0.15 MPa of increasing internal pressure during the reaction. In this system, reductive dechlorination by metallic calcium and catalytic reduction by Rh/C and generated hydrogen gas, without any external addition of hydrogen, exert a synergistic effect on the degradation of chlorinated compounds. Alcohol was used as a proton source and hydrogen, which was generated by a side reaction, causes an increase in the activity of Rh/C catalyst. Through the degradation of 4-chloroanisole in ethyl alcohol, anisole and cyclohexyl methyl ether were obtained in good conversions. Using ethyl alcohol as a solvent, treatment of dioxins and co-PCBs in a solution was markedly effective for degradation to reduce 2806 pg TEQ/ml of initial concentration to 31.8 pg TEQ/ml; its yield was 98.5%. Moreover, degradation in methyl alcohol took place in a 99.3% yield. That concentration ultimately reached 20.3 pg TEQ/ml under a mild wet process. All congeners of dioxins and co-PCBs were degraded in high conversions. In this degradation, lower aliphatic alcohol, such as methyl alcohol, is effective for making a new calcium surface as compared to alcohol with more methylene chains. In addition, it seemed that a higher pressure of hydrogen was easily generated in methyl alcohol, and then catalytic degradation was effectivley influenced. PMID:16570607

  12. Reduced birthweight and length in the offspring of females exposed to PCDFs, PCP, and lindane.

    PubMed Central

    Karmaus, W; Wolf, N

    1995-01-01

    The objective of this study was to investigate a broad range of adverse health outcomes and their potential association to wood preservative used in daycare centers. This article focuses on reproductive effects. A sample of 221 exposed teachers was provided by the employer's liability insurers. A comparison group (n = 189) insured by the same two organizations was recruited from nonexposed daycare centers. In a face-to-face interview, job history and reproductive history of 398 female teachers were ascertained. Data on exposure were provided, including measurements on concentration of pentachlorophenol (PCP) and lindane in wood panels, and of PCP, lindane, polychlorinated dibenzo-p-dioxins and dibenzofurans in indoor air. An exposure matrix based on individual job history, independent exposure information from each center, and reproductive history was set up with regard to the vulnerable time windows for each pregnancy. Using this approach, 49 exposed and 507 nonexposed pregnancies were identified, including 32 exposed and 386 nonexposed live births. For subgroup analyses the observations were restricted to independent pregnancies, excluding multiple and consecutive births. The data were analyzed with linear regression techniques, taking confounders into account. The crude median difference between exposed and nonexposed was 175 g in birthweight and 2 cm in length. Controlling for confounders, the results show a significantly reduced but weight (p = 0.04) and length (p = 0.02) in exposed pregnancies, even after restricting the data to independent pregnancies and pregnancies for which data could be validated from the mother's health cards. These differences were not explained by differences in gestational age indicating that a toxic effect, which could cause small-for date newborns, might have affected the fetus. Images Figure 1. Figure 2. Figure 3. PMID:8747018

  13. Concentrations of PCDD/PCDFs and PCBs in spent foundry sands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Approximately 10 million tons of spent foundry sand (SFS) are generated in the U.S. each year, and their beneficial use in agricultural and horticultural applications is being considered. Other studies have demonstrated that trace elements are low enough in sands from iron, steel, and aluminum foun...

  14. ON-ROAD EMISSIONS OF PCDDS AND PCDFS FROM HEAVY DUTY DIESEL VEHICLES

    EPA Science Inventory

    This work characterized emission factors, homologue profiles, and isomer patterns of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs) from on-road sampling of three heavy duty diesel vehicles (HDDVS) under various conditions of city and highway drivi...

  15. PCDDs, PCDFs and PCBs in farmed fish produced in Greece: Levels and human population exposure assessment.

    PubMed

    Costopoulou, Danae; Vassiliadou, Irene; Leondiadis, Leondios

    2016-03-01

    Fish is among the essential components of Mediterranean diet and has beneficial effects on human health. Farmed fish is an affordable alternative to wild fish and a significant food export product for Greece. Published studies worldwide have reported significant levels of environmental pollutants in fish tissues. Especially for PCDDs/Fs and PCBs, the studies suggest that the most important contribution to human dietary intake is from fish and seafood. In the present study, we investigate the levels of PCDDs/Fs, dioxin-like and non dioxin-like PCBs in the most common farmed fish species produced in Greece i.e. sea bass, sea bream and rainbow trout. These species are widely consumed in Greece and are also exported to many countries worldwide. The mean levels found were WHO-PCDD/F-TEQ: 0.22 pg g(-1) wet weight (w.w.), WHO-PCDD/F-PCB-TEQ: 0.88 pg g(-1) w.w. for sea bream, WHO-PCDD/F-TEQ: 0.13 pg g(-1) w.w., WHO-PCDD/F-PCB-TEQ: 0.68 pg g(-1) w.w. for sea bass and WHO-PCDD/F-TEQ: 0.10 pg g(-1) w.w., WHO-PCDD/F-PCB-TEQ: 0.43 pg g(-1) w.w. for rainbow trout. For non dioxin-like PCBs, mean sum values found were 8.02 ng g(-1) w.w. for sea bream, 5.24 ng g(-1) w.w. for sea bass and 2.90 ng g(-1) w.w. for rainbow trout. All concentrations found were far below maximum levels set by the European Union and in the same range as wild-caught fish also presented for comparison. Daily intake from the consumption of farmed fish species examined is calculated at 1.3 pg WHO-TEQ kg(-1) b.w., which is at the lowest end of TDI values proposed by the WHO. PMID:26745380

  16. Validation of emission test method for PCDs and PCDFs: Work assignment No. 23. Final report

    SciTech Connect

    Coates, J.T.

    1990-03-01

    The precision and accuracy of the Modified Method Five (MM5) sampling and analysis scheme for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF) in municipal waste combustor stack gas have been determined. This was accomplished using a dynamic spiking system designed to continuously deliver stable isotopic PCDD/PCDF congeners into the MM5 sampling train upstream of the particulate filter during sampling of incinerator stack gas. Field validation tests to measure the recovery of statically and dynamically spiked PCDD/PCDF during stack gas sampling indicated that the resin effectively retained the static spike during operating conditions. Dynamic spike recoveries were inadequate, partially due to the use of dichloromethane as the extraction solvent. Toluene was subsequently shown to be more appropriate than dichloromethane for obtaining enhanced recoveries of PCDD/PCDF. The overall sampling and analysis scheme as recommended in the report was estimated as at better than 80% for the accuracy and as at + or - 35% for the precision.

  17. Acceptance test report for portable exhauster POR-008/Skid F

    SciTech Connect

    Kriskovich, J.R.

    1998-07-24

    Portable Exhauster POR-008 was procured via HNF-0490, Specification for a Portable Exhausted System for Waste Tank Ventilation. Prior to taking ownership, acceptance testing was performed at the vendors. However at the conclusion of testing a number of issues remained that required resolution before the exhausters could be used by Project W-320. The purpose of acceptance testing documented by this report was to demonstrate compliance of the exhausters with the performance criteria established within HNF-O49O, Rev. 1 following a repair and upgrade effort at Hanford. In addition, data obtained during this testing is required for the resolution of outstanding Non-conformance Reports (NCR), and finally, to demonstrate the functionality of the associated software for the pressure control and high vacuum exhauster operating modes provided for by W-320. Additional testing not required by the ATP was also performed to assist in the disposition and close out of receiving inspection report and for application design information (system curve). Results of this testing are also captured within this document.

  18. VDAC and the bacterial porin PorB of Neisseria gonorrhoeae share mitochondrial import pathways.

    PubMed

    Müller, Anne; Rassow, Joachim; Grimm, Jan; Machuy, Nikolaus; Meyer, Thomas F; Rudel, Thomas

    2002-04-15

    The human pathogen Neisseria gonorrhoeae induces host cell apoptosis during infection by delivering the outer membrane protein PorB to the host cell's mitochondria. PorB is a pore-forming beta-barrel protein sharing several features with the mitochondrial voltage-dependent anion channel (VDAC), which is involved in the regulation of apoptosis. Here we show that PorB of pathogenic Neisseria species produced by host cells is efficiently targeted to mitochondria. Imported PorB resides in the mitochondrial outer membrane and forms multimers with similar sizes as in the outer bacterial membrane. The mitochondria completely lose their membrane potential, a characteristic previously observed in cells infected with gonococci or treated with purified PorB. Closely related bacterial porins of non-pathogenic Neisseria mucosa or Escherichia coli remain in the cytosol. Import of PorB into mitochondria in vivo is independent of a linear signal sequence. Insertion of PorB into the mitochondrial outer membrane in vitro depends on the activity of Tom5, Tom20 and Tom40, but is independent of Tom70. Our data show that human VDAC and bacterial PorB are imported into mitochondria by a similar mechanism. PMID:11953311

  19. Successful Mnemonics for "por"/"para" and Affirmative Commands with Pronouns.

    ERIC Educational Resources Information Center

    Mason, Keith

    1992-01-01

    Two mnemonic devices, "4A Rule" and "PERFECT," are described to simplify the learning of two grammar points: the placement of object pronouns with respect to commands and the distinction between "por" and "para." (five references) (LB)

  20. Genome Sequences of Pseudomonas oryzihabitans Phage POR1 and Pseudomonas aeruginosa Phage PAE1.

    PubMed

    Dyson, Zoe A; Seviour, Robert J; Tucci, Joseph; Petrovski, Steve

    2016-01-01

    We report the genome sequences of two double-stranded DNA siphoviruses, POR1 infective for Pseudomonas oryzihabitans and PAE1 infective for Pseudomonas aeruginosa The phage POR1 genome showed no nucleotide sequence homology to any other DNA phage sequence in the GenBank database, while phage PAE1 displayed synteny to P. aeruginosa phages M6, MP1412, and YuA. PMID:27313312

  1. Genome Sequences of Pseudomonas oryzihabitans Phage POR1 and Pseudomonas aeruginosa Phage PAE1

    PubMed Central

    Dyson, Zoe A.; Seviour, Robert J.; Tucci, Joseph

    2016-01-01

    We report the genome sequences of two double-stranded DNA siphoviruses, POR1 infective for Pseudomonas oryzihabitans and PAE1 infective for Pseudomonas aeruginosa. The phage POR1 genome showed no nucleotide sequence homology to any other DNA phage sequence in the GenBank database, while phage PAE1 displayed synteny to P. aeruginosa phages M6, MP1412, and YuA. PMID:27313312

  2. Crystallographic analysis of Neisseria meningitidis PorB extracellular loops potentially implicated in TLR2 recognition.

    PubMed

    Kattner, Christof; Toussi, Deana N; Zaucha, Jan; Wetzler, Lee M; Rüppel, Nadine; Zachariae, Ulrich; Massari, Paola; Tanabe, Mikio

    2014-03-01

    Among all Neisseriae species, Neisseria meningitidis and Neisseria gonorrhoeae are the only human pathogens, causative agents of bacterial meningitis and gonorrhoea, respectively. PorB, a pan-Neisseriae trimeric porin that mediates diffusive transport of essential molecules across the bacterial outer membrane, is also known to activate host innate immunity via Toll-like receptor 2 (TLR2)-mediated signaling. The molecular mechanism of PorB binding to TLR2 is not known, but it has been hypothesized that electrostatic interactions contribute to ligand/receptor binding. Strain-specific sequence variability in the surface-exposed loops of PorB which are potentially implicated in TLR2 binding, may explain the difference in TLR2-mediated cell activation in vitro by PorB homologs from the commensal Neisseriae lactamica and the pathogen N. meningitidis. Here, we report a comparative structural analysis of PorB from N. meningitidis serogroup B strain 8765 (63% sequence homology with PorB from N. meningitidis serogroup W135) and a mutant in which amino acid substitutions in the extracellular loop 7 lead to significantly reduced TLR2-dependent activity in vitro. We observe that this mutation both alters the loop conformation and causes dramatic changes of electrostatic surface charge, both of which may affect TLR2 recognition and signaling. PMID:24361688

  3. Structural basis for solute transport, nucleotide regulation, and immunological recognition of Neisseria meningitidis PorB

    SciTech Connect

    Tanabe, Mikio; Nimigean, Crina M.; Iverson, T.M.

    2010-06-25

    PorB is the second most prevalent outer membrane protein in Neisseria meningitidis. PorB is required for neisserial pathogenesis and can elicit a Toll-like receptor mediated host immune response. Here, the x-ray crystal structure of PorB has been determined to 2.3 {angstrom} resolution. Structural analysis and cocrystallization studies identify three putative solute translocation pathways through the channel pore: One pathway transports anions nonselectively, one transports cations nonselectively, and one facilitates the specific uptake of sugars. During infection, PorB likely binds host mitochondrial ATP, and cocrystallization with the ATP analog AMP-PNP suggests that binding of nucleotides regulates these translocation pathways both by partial occlusion of the pore and by restricting the motion of a putative voltage gating loop. PorB is located on the surface of N. meningitidis and can be recognized by receptors of the host innate immune system. Features of PorB suggest that Toll-like receptor mediated recognition outer membrane proteins may be initiated with a nonspecific electrostatic attraction.

  4. Structural basis for solute transport, nucleotide regulation, and immunological recognition of Neisseria meningitidis PorB

    PubMed Central

    Tanabe, Mikio; Nimigean, Crina M.; Iverson, T. M.

    2010-01-01

    PorB is the second most prevalent outer membrane protein in Neisseria meningitidis. PorB is required for neisserial pathogenesis and can elicit a Toll-like receptor mediated host immune response. Here, the x-ray crystal structure of PorB has been determined to 2.3 Å resolution. Structural analysis and cocrystallization studies identify three putative solute translocation pathways through the channel pore: One pathway transports anions nonselectively, one transports cations nonselectively, and one facilitates the specific uptake of sugars. During infection, PorB likely binds host mitochondrial ATP, and cocrystallization with the ATP analog AMP–PNP suggests that binding of nucleotides regulates these translocation pathways both by partial occlusion of the pore and by restricting the motion of a putative voltage gating loop. PorB is located on the surface of N. meningitidis and can be recognized by receptors of the host innate immune system. Features of PorB suggest that Toll-like receptor mediated recognition outer membrane proteins may be initiated with a nonspecific electrostatic attraction. PMID:20351243

  5. An investigation of exploitation versus exploration in GBEA optimization of PORS 15 and 16 Problems

    SciTech Connect

    Koch, Kaelynn

    2012-01-01

    It was hypothesized that the variations in time to solution are driven by the competing mechanisms of exploration and exploitation.This thesis explores this hypothesis by examining two contrasting problems that embody the hypothesized tradeoff between exploration and exploitation. Plus one recall store (PORS) is an optimization problem based on the idea of a simple calculator with four buttons: plus, one, store, and recall. Integer addition and store are classified as operations, and one and memory recall are classified as terminals. The goal is to arrange a fixed number of keystrokes in a way that maximizes the numerical result. PORS 15 (15 keystrokes) represents the subset of difficult PORS problems and PORS 16 (16 keystrokes) represents the subset of PORS problems that are easiest to optimize. The goal of this work is to examine the tradeoff between exploitation and exploration in graph based evolutionary algorithm (GBEA) optimization. To do this, computational experiments are used to examine how solutions evolve in PORS 15 and 16 problems when solved using GBEAs. The experiment is comprised of three components; the graphs and the population, the evolutionary algorithm rule set, and the example problems. The complete, hypercube, and cycle graphs were used for this experiment. A fixed population size was used.

  6. Molecular characterisation of Porcine rubulavirus (PorPV) isolates from different outbreaks in Mexico.

    PubMed

    Cuevas-Romero, S; Rivera-Benítez, J F; Blomström, A-L; Ramliden, M; Hernández-Baumgarten, E; Hernández-Jáuregui, P; Ramírez-Mendoza, H; Berg, M

    2016-02-01

    Since the report of the initial outbreak of Porcine rubulavirus (PorPV) infection in pigs, only one full-length genome from 1984 (PorPV-LPMV/1984) has been characterised. To investigate the overall genetic variation, full-length gene nucleotide sequences of current PorPV isolates were obtained from different clinical cases of infected swine. Genome organisation and sequence analysis of the encoded proteins (NP, P, F, M, HN and L) revealed high sequence conservation of the NP protein and the expression of the P and V proteins in all PorPV isolates. The V protein of one isolate displayed a mutation that has been implicated to antagonise the antiviral immune responses of the host. The M protein indicated a variation in a short region that could affect the electrostatic charge and the interaction with the membrane. One PorPV isolate recovered from the lungs showed a mutation at the cleavage site (HRKKR) of the F protein that could represent an important factor to determine the tissue tropism and pathogenicity of this virus. The HN protein showed high sequence identity through the years (up to 2013). Additionally, a number of sequence motifs of very high amino acid conservation among the PorPV isolates important for polymerase activity of the L protein have been identified. In summary, genetic comparisons and phylogenetic analyses indicated that three different genetic variants of PorPV are currently spreading within the swine population, and a new generation of circulating virus with different characteristics has begun to emerge. PMID:26728078

  7. Por Secretion System-Dependent Secretion and Glycosylation of Porphyromonas gingivalis Hemin-Binding Protein 35

    PubMed Central

    Shoji, Mikio; Sato, Keiko; Yukitake, Hideharu; Kondo, Yoshio; Narita, Yuka; Kadowaki, Tomoko; Naito, Mariko; Nakayama, Koji

    2011-01-01

    The anaerobic Gram-negative bacterium Porphyromonas gingivalis is a major pathogen in severe forms of periodontal disease and refractory periapical perodontitis. We have recently found that P. gingivalis has a novel secretion system named the Por secretion system (PorSS), which is responsible for secretion of major extracellular proteinases, Arg-gingipains (Rgps) and Lys-gingipain. These proteinases contain conserved C-terminal domains (CTDs) in their C-termini. Hemin-binding protein 35 (HBP35), which is one of the outer membrane proteins of P. gingivalis and contributes to its haem utilization, also contains a CTD, suggesting that HBP35 is translocated to the cell surface via the PorSS. In this study, immunoblot analysis of P. gingivalis mutants deficient in the PorSS or in the biosynthesis of anionic polysaccharide-lipopolysaccharide (A-LPS) revealed that HBP35 is translocated to the cell surface via the PorSS and is glycosylated with A-LPS. From deletion analysis with a GFP-CTD[HBP35] green fluorescent protein fusion, the C-terminal 22 amino acid residues of CTD[HBP35] were found to be required for cell surface translocation and glycosylation. The GFP-CTD fusion study also revealed that the CTDs of CPG70, peptidylarginine deiminase, P27 and RgpB play roles in PorSS-dependent translocation and glycosylation. However, CTD-region peptides were not found in samples of glycosylated HBP35 protein by peptide map fingerprinting analysis, and antibodies against CTD-regions peptides did not react with glycosylated HBP35 protein. These results suggest both that the CTD region functions as a recognition signal for the PorSS and that glycosylation of CTD proteins occurs after removal of the CTD region. Rabbits were used for making antisera against bacterial proteins in this study. PMID:21731719

  8. Gliding Motility and Por Secretion System Genes Are Widespread among Members of the Phylum Bacteroidetes

    PubMed Central

    Zhu, Yongtao

    2013-01-01

    The phylum Bacteroidetes is large and diverse, with rapid gliding motility and the ability to digest macromolecules associated with many genera and species. Recently, a novel protein secretion system, the Por secretion system (PorSS), was identified in two members of the phylum, the gliding bacterium Flavobacterium johnsoniae and the nonmotile oral pathogen Porphyromonas gingivalis. The components of the PorSS are not similar in sequence to those of other well-studied bacterial secretion systems. The F. johnsoniae PorSS genes are a subset of the gliding motility genes, suggesting a role for the secretion system in motility. The F. johnsoniae PorSS is needed for assembly of the gliding motility apparatus and for secretion of a chitinase, and the P. gingivalis PorSS is involved in secretion of gingipain protease virulence factors. Comparative analysis of 37 genomes of members of the phylum Bacteroidetes revealed the widespread occurrence of gliding motility genes and PorSS genes. Genes associated with other bacterial protein secretion systems were less common. The results suggest that gliding motility is more common than previously reported. Microscopic observations confirmed that organisms previously described as nonmotile, including Croceibacter atlanticus, “Gramella forsetii,” Paludibacter propionicigenes, Riemerella anatipestifer, and Robiginitalea biformata, exhibit gliding motility. Three genes (gldA, gldF, and gldG) that encode an apparent ATP-binding cassette transporter required for F. johnsoniae gliding were absent from two related gliding bacteria, suggesting that the transporter may not be central to gliding motility. PMID:23123910

  9. Oral administration of recombinant Neisseria meningitidis PorA genetically fused to H. pylori HpaA antigen increases antibody levels in mouse serum, suggesting that PorA behaves as a putative adjuvant.

    PubMed

    Vasquez, Abel E; Manzo, Ricardo A; Soto, Daniel A; Barrientos, Magaly J; Maldonado, Aurora E; Mosqueira, Macarena; Avila, Anastasia; Touma, Jorge; Bruce, Elsa; Harris, Paul R; Venegas, Alejandro

    2015-01-01

    The Neisseria meningitidis outer membrane protein PorA from a Chilean strain was purified as a recombinant protein. PorA mixed with AbISCO induced bactericidal antibodies against N. meningitidis in mice. When PorA was fused to the Helicobacter pylori HpaA antigen gene, the specific response against H. pylori protein increased. Splenocytes from PorA-immunized mice were stimulated with PorA, and an increase in the secretion of IL-4 was observed compared with that of IFN-γ. Moreover, in an immunoglobulin sub-typing analysis, a substantially higher IgG1 level was found compared with IgG2a levels, suggesting a Th2-type immune response. This study revealed a peculiar behavior of the purified recombinant PorA protein per se in the absence of AbISCO as an adjuvant. Therefore, the resistance of PorA to proteolytic enzymes, such as those in the gastrointestinal tract, was analyzed, because this is an important feature for an oral protein adjuvant. Finally, we found that PorA fused to the H. pylori HpaA antigen, when expressed in Lactococcus lactis and administered orally, could enhance the antibody response against the HpaA antigen approximately 3 fold. These observations strongly suggest that PorA behaves as an effective oral adjuvant. PMID:25750999

  10. Oral administration of recombinant Neisseria meningitidis PorA genetically fused to H. pylori HpaA antigen increases antibody levels in mouse serum, suggesting that PorA behaves as a putative adjuvant

    PubMed Central

    Vasquez, Abel E; Manzo, Ricardo A; Soto, Daniel A; Barrientos, Magaly J; Maldonado, Aurora E; Mosqueira, Macarena; Avila, Anastasia; Touma, Jorge; Bruce, Elsa; Harris, Paul R; Venegas, Alejandro

    2015-01-01

    The Neisseria meningitidis outer membrane protein PorA from a Chilean strain was purified as a recombinant protein. PorA mixed with AbISCO induced bactericidal antibodies against N. meningitidis in mice. When PorA was fused to the Helicobacter pylori HpaA antigen gene, the specific response against H. pylori protein increased. Splenocytes from PorA-immunized mice were stimulated with PorA, and an increase in the secretion of IL-4 was observed compared with that of IFN-γ. Moreover, in an immunoglobulin sub-typing analysis, a substantially higher IgG1 level was found compared with IgG2a levels, suggesting a Th2-type immune response. This study revealed a peculiar behavior of the purified recombinant PorA protein per se in the absence of AbISCO as an adjuvant. Therefore, the resistance of PorA to proteolytic enzymes, such as those in the gastrointestinal tract, was analyzed, because this is an important feature for an oral protein adjuvant. Finally, we found that PorA fused to the H. pylori HpaA antigen, when expressed in Lactococcus lactis and administered orally, could enhance the antibody response against the HpaA antigen approximately 3 fold. These observations strongly suggest that PorA behaves as an effective oral adjuvant. PMID:25750999

  11. An Analysis of Interlanguage Development Over Time: Part 1, "por" and "para".

    ERIC Educational Resources Information Center

    Guntermann, Gail

    1992-01-01

    The first part of a larger planned investigation, this study examines the use of "por" and "para" by nine Peace Corps volunteers in oral interviews at the end of training and roughly one year later, to trace their acquisition over time, in two learning contexts. (24 references) (LB)

  12. The Acquisition of Lexical Meaning in a Study Abroad Context: The Spanish Prepositions "por" and "para."

    ERIC Educational Resources Information Center

    Lafford, Barbara A.; Ryan, John M.

    1995-01-01

    Examination of the development of form/function relations of the prepositions "por" and "para" at different levels of proficiency in the interlanguage of study-abroad students in Granada, Spain, revealed "noncanonical" as well as "canonical" uses of these prepositions. The most common noncanonical uses were as substitutions for other prepositions…

  13. The porA gene in serogroup A meningococci: evolutionary stability and mechanism of genetic variation.

    PubMed

    Suker, J; Feavers, I M; Achtman, M; Morelli, G; Wang, J F; Maiden, M C

    1994-04-01

    Molecular analyses were applied to the genes encoding variants of the serosubtyping antigen, the class 1 outer membrane protein (PorA), from 55 serogroup A Neisseria meningitidis strains. These genes were evolutionarily stable and exhibited a limited range of genetic variation, primarily generated by recombination. Translation of the gene sequences revealed a total of 19 distinct amino acid sequences in the variable regions of the protein, 6 of which were not recognized by currently available serosubtyping monoclonal antibodies. Knowledge of these amino acid sequences permitted a rational re-assignment of serosubtype names. Comparison of the complete genes with porA gene sequences from serogroup B and C meningococci showed that serogroup A possessed a limited number of the possible porA genes from a globally distributed gene pool. Each serogroup A subgroup was characterized by one of four porA gene types, probably acquired upon subgroup divergence, which was stable over periods of decades and during epidemiological spread. Comparison with other variable genes (pil and iga) indicated that the three alleles were independently assorted within the subgroup, suggesting that their gene types were older than the subgroups in which they occurred. PMID:8057850

  14. Informe a la Nación de mortalidad por cáncer sigue bajando

    Cancer.gov

    El Informe Anual a la Nación sobre el Estado del Cáncer, de 1975 a 2009, indica que los índices generales de mortalidad por cáncer siguen bajando en los Estados Unidos en hombres y mujeres, entre todos los grupos raciales y étnicos principales y para todo

  15. Detección y estudio mediante Fluorescencia Inducida por Láser de radicales libres formados por Disociación Multifotónica Infrarroja

    NASA Astrophysics Data System (ADS)

    Santos, M.; Díaz, L.; Torresano, J. A.; Rubio, L.; Samoudi, B.

    Una de las principales aplicaciones actuales de los procesos de disociación multifotónica inducidos por radiación láser infrarroja (DMI) es la producción de radiales libres, con el fin de estudiar sus propiedades cinéticas y espectroscópicas. La disociación de moléculas poliatómicas en el IR con láseres de CO2 tiene lugar desde la superficie de energía molecular mas baja y conduce generalmente a la formación de fragmentos en el estado electrónico fundamental, con diversos grados de excitación vibracional. En el Grupo de Procesos Multifotónicos del Instituto de Estructura de la Materia del C.S.I.C. hemos puesto a punto la técnica de Fluorescencia Inducida por Láser (LIF) para la detección y análisis en tiempo real de los fragmentos producidos en la DMI inducida mediante uno o dos campos láseres de diferentes longitudes de onda. Objetivos de nuestro trabajo han sido el estudio de los canales de disociación mayoritarios y de las especies transitoria producidas, así como de la distribución de energía interna con que éstas son generadas. En particular hemos detectado mediante LIF las especies: C2, CF, CH, SiH2, CF2, CH2, SiHCl, y CF3 a partir de la disociación de, entre otras, las siguientes moléculas: C2H3Br, C3F6, C4H8Si, C2H5ClSi y CH5ClSi. En este trabajo presentamos algunos de los resultados obtenidos mediante el estudio por LIF de estos radicales: estudio temporal de la señal LIF obtenida con determinación de tiempos de vida, espectros de excitación y fluorescencia, temperaturas vibracionales de formación, variación de la intensidad LIF con el tiempo de retraso entre los láseres de disociación y prueba, etc.

  16. ATP for the portable 500 CFM exhauster POR-005 skid C

    SciTech Connect

    Keller, C.M.

    1997-06-27

    This Acceptance Test Plan is for a 500 CFM Portable Exhauster POR-005 to be used for saltwell pumping. The Portable Exhauster System will be utilized to eliminate potential flammable gases that may exist within the dome space of the tank. This Acceptance Plan will test and verify that the exhauster meets the specified design criteria, safety requirements, operations requirements, and will provide a record of the functional test results.

  17. ATP for the portable 500 CFM exhauster POR-006 skid D

    SciTech Connect

    Keller, C.M.

    1997-07-29

    This Acceptance Test Plan is for a 500 CFM Portable Exhauster POR-006 to be used for saltwell pumping. The Portable Exhauster System will be utilized to eliminate potential flammable gases that may exist within the dome space of the tank. This Acceptance Plan will test and verify that the exhauster meets the specified design criteria, safety requirements, operations requirements, and will provide a record of the functional test results.

  18. ATP for the portable 500 CFM exhauster POR-004 skid B

    SciTech Connect

    Keller, C.M.

    1997-05-06

    This Acceptance Test Plan is for a 500 CFM Portable Exhauster POR-004 to be used for saltwell pumping. The Portable Exhauster System will be utilized to eliminate potential flammable gases that may exist within the dome space of the tank. This Acceptance Plan will test and verify that the exhauster meets the specified design criteria, safety requirements, operations requirements, and will provide a record of the functional test results.

  19. Levels of PCDDs, PCDFs and dioxin-like PCBs in raw cow's milk collected in France in 2006.

    PubMed

    Durand, Benoit; Dufour, Barbara; Fraisse, Daniel; Defour, Stéphanie; Duhem, Koenraad; Le-Barillec, Karine

    2008-01-01

    Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) as well as polychlorinated biphenyls (PCBs) are widespread environmental contaminants. A French national survey was carried out in April 2006 to assess the concentrations of PCDD/Fs and dioxin-like PCBs (DL-PCBs) in raw cow's milk. A random sampling scheme stratified by region was applied to collect 239 raw milk samples from 93 plants belonging to 17 dairy companies. Compared to a previous survey led in 1998 analyzing half-skimmed drinking milk in France, the PCDD/Fs level was cut by half, with an average concentration of 0.33 pg toxic equivalent (TEQ)/g fat in 2006. The mean DL-PCBs concentration was 0.57 pg TEQ/g fat and subsequently the sum of PCDD/Fs and DL-PCBs was 0.90 pg/g fat, values below the thresholds defined by the European Union regulations. PMID:17707881

  20. Relative potency based on hepatic enzyme induction predicts immunosuppressive effects of a mixture of PCDDS/PCDFS and PCBS

    SciTech Connect

    Smialowicz, R.J.; DeVito, M.J. Williams, W.C.; Birnbaum, L.S.

    2008-03-15

    The toxic equivalency factor (TEF) approach was employed to compare immunotoxic potency of mixtures containing polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), using the antibody response to sheep erythrocytes (SRBC). Mixture-1 (MIX-1) contained TCDD, 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PeCDD), 2,3,7,8-tetrachlorodibenzofuran (TCDF), 1,2,3,7,8-pentachlorodibenzofuran (1-PeCDF), 2,3,4,7,8-pentachlorodibenzofuran (4-PeCDF), and 1,2,3,4,6,7,8,9-octachlorodibenzofuran (OCDF). Mixture-2 (MIX-2) contained MIX-1 and the following PCBs, 3,3',4,4'-tetrachlorobiphenyl (IUPAC No. 77), 3,3',4,4',5-pentachlorobiphenyl (126), 3,3',4,4',5,5N-hexachlorobiphenyl (169), 2,3,3',4,4'-pentachlorobiphenyl (105), 2,3',4,4',5-pentachlorobiphenyl (118), and 2,3,3',4,4',5-hexachlorobiphenyl (156). The mixture compositions were based on relative chemical concentrations in food and human tissues. TCDD equivalents (TEQ) of the mixture were estimated using relative potency factors from hepatic enzyme induction in mice [DeVito, M.J., Diliberto, J.J., Ross, D.G., Menache, M.G., Birnbaum, L.S., 1997. Dose-response relationships for polyhalogenated dioxins and dibenzofurans following subchronic treatment in mice. I .CYP1A1 and CYP1A2 enzyme activity in liver, lung and skin. Toxicol. Appl. Pharmacol. 130, 197-208; DeVito, M.J., Menache, G., Diliberto, J.J., Ross, D.G., Birnbaum L.S., 2000. Dose-response relationships for induction of CYP1A1 and CYP1A2 enzyme activity in liver, lung, and skin in female mice following subchronic exposure to polychlorinated biphenyls. Toxicol. Appl. Pharmacol. 167, 157-172] Female mice received 0, 1.5, 15, 150 or 450 ng TCDD/kg/day or approximately 0, 1.5, 15, 150 or 450 ng TEQ/kg/day of MIX-1 or MIX-2 by gavage 5 days per week for 13 weeks. Mice were immunized 3 days after the last exposure and 4 days later, body, spleen, thymus, and liver weights were measured, and antibody response to SRBCs was observed. Exposure to TCDD, MIX-1, and MIX-2 suppressed the antibody response in a dose-dependent manner. Two-way ANOVA indicated no differences in the response between TCDD and the mixtures for body weight, spleen/body weight and decreased antibody responses. The results support the use of the TEF methodology and suggest that immune suppression by dioxin-like chemicals may be of concern at or near background human exposures.

  1. ASSESSMENT OF PCDDS (POLYCHLORINATED DIBENZODIOXINS) AND PCDFS (POLYCHLORINATED DIBENZOFURANS) FROM PCB (POLYCHLORINATED BIPHENYL'S) TRANSFORMER AND CAPACITOR FIRES

    EPA Science Inventory

    The EPA, under the Toxic Substances Control Act, has been mandated to develop appropriate regulations for the control of exposure to polychlorinated biphenyls (PCBs). In light of this responsibility the EPA Office of Toxic Substances recently issued an Advance Notice of Proposed ...

  2. Correlation between Serological and Sequencing Analyses of the PorB Outer Membrane Protein in the Neisseria meningitidis Serotyping System

    PubMed Central

    Sacchi, Claudio T.; Lemos, Ana P. S.; Whitney, Anne M.; Solari, Claude A.; Brandt, Mary E.; Melles, Carmo E. A.; Frasch, Carl E.; Mayer, Leonard W.

    1998-01-01

    The current serological typing scheme for Neisseria meningitidis is not comprehensive; a proportion of isolates are not serotypeable. DNA sequence analysis and predicted amino acid sequences were used to characterize the structures of variable-region (VR) epitopes on N. meningitidis PorB proteins (PorB VR typing). Twenty-six porB gene sequences were obtained from GenBank and aligned with 41 new sequences. Primary amino acid structures predicted from those genes were grouped into 30 VR families of related variants that displayed at least 60% similarity. We correlated VR families with monoclonal antibody (MAb) reactivities, establishing a relationship between VR families and epitope locations for 15 serotype-defining MAbs. The current panel of serotype-defining MAbs underestimates by at least 50% the PorB VR variability because reagents for several major VR families are lacking or because a number of VR variants within some families are not recognized by serotype-defining MAbs. These difficulties, also reported for serosubtyping based on the PorA protein, are shown as inconsistent results between serological and sequence analyses, leading to inaccurate strain identification and incomplete epidemiological data. The information from this study enabled the expansion of the panel of MAbs currently available for serotyping, by including MAbs of previously undetermined specificities. Use of the expanded serotype panel enabled us to improve the sensitivity of serotyping by resolving a number of formerly nonserotypeable strains. In most cases, this information can be used to predict the VR family placement of unknown PorB proteins without sequencing the entire porB gene. PorB VR typing complements serotyping, and a combination of both techniques may be used for full characterization of meningococcal strains. The present work represents the most complete and integrated data set of PorB VR sequences and MAb reactivities of serogroup B and C meningococci produced to date. PMID

  3. Zinc Finger Nuclease Knock-out of NADPH:Cytochrome P450 Oxidoreductase (POR) in Human Tumor Cell Lines Demonstrates That Hypoxia-activated Prodrugs Differ in POR Dependence*

    PubMed Central

    Su, Jiechuang; Gu, Yongchuan; Pruijn, Frederik B.; Smaill, Jeff B.; Patterson, Adam V.; Guise, Christopher P.; Wilson, William R.

    2013-01-01

    Hypoxia, a ubiquitous feature of tumors, can be exploited by hypoxia-activated prodrugs (HAP) that are substrates for one-electron reduction in the absence of oxygen. NADPH:cytochrome P450 oxidoreductase (POR) is considered one of the major enzymes responsible, based on studies using purified enzyme or forced overexpression in cell lines. To examine the role of POR in HAP activation at endogenous levels of expression, POR knock-outs were generated in HCT116 and SiHa cells by targeted mutation of exon 8 using zinc finger nucleases. Absolute quantitation by proteotypic peptide mass spectrometry of DNA sequence-confirmed multiallelic mutants demonstrated expression of proteins with residual one-electron reductase activity in some clones and identified two (Hko2 from HCT116 and S2ko1 from SiHa) that were functionally null by multiple criteria. Sensitivities of the clones to 11 HAP (six nitroaromatics, three benzotriazine N-oxides, and two quinones) were compared with wild-type and POR-overexpressing cells. All except the quinones were potentiated by POR overexpression. Knocking out POR had a marked effect on antiproliferative activity of the 5-nitroquinoline SN24349 in both genetic backgrounds after anoxic exposure but little or no effect on activity of most other HAP, including the clinical stage 2-nitroimidazole mustard TH-302, dinitrobenzamide mustard PR-104A, and benzotriazine N-oxide SN30000. Clonogenic cell killing and reductive metabolism of PR-104A and SN30000 under anoxia also showed little change in the POR knock-outs. Thus, although POR expression is a potential biomarker of sensitivity to some HAP, identification of other one-electron reductases responsible for HAP activation is needed for their rational clinical development. PMID:24196959

  4. Characterization of Plasmid pOR1 from Ornithobacterium rhinotracheale and Construction of a Shuttle Plasmid

    PubMed Central

    Jansen, Ruud; Chansiripornchai, Niwat; Gaastra, Wim; van Putten, Jos P. M.

    2004-01-01

    The bacterium Ornithobacterium rhinotracheale has been recognized as an emerging pathogen in poultry since about 10 years ago. Knowledge of this bacterium and its mechanisms of virulence is still very limited. Here we report the development of a transformation system that enables genetic modification of O. rhinotracheale. The system is based on a cryptic plasmid, pOR1, that was derived from an O. rhinotracheale strain of serotype K. Sequencing indicated that the plasmid consisted of 14,787 nucleotides. Sequence analysis revealed one replication origin and several rep genes that control plasmid replication and copy number, respectively. In addition, pOR1 contains genes with similarity to a heavy-metal-transporting ATPase, a TonB-linked siderophore receptor, and a laccase. Reverse transcription-PCR demonstrated that these genes were transcribed. Other putative open reading frames exhibited similarities with a virulence-associated protein in Actinobacillus actinomycetemcomitans and a number of genes coding for proteins with unknown function. An Escherichia coli-O. rhinotracheale shuttle plasmid (pOREC1) was constructed by cloning the replication origin and rep genes from pOR1 and the cfxA gene from Bacteroides vulgatus, which codes for resistance to the antibiotic cefoxitin, into plasmid pGEM7 by using E. coli as a host. pOREC1 was electroporated into O. rhinotracheale and yielded cefoxitin-resistant transformants. The pOREC1 isolated from these transformants was reintroduced into E. coli, demonstrating that pOREC1 acts as an independent replicon in both E. coli and O. rhinotracheale, fulfilling the criteria for a shuttle plasmid that can be used for transformation, targeted mutagenesis, and the construction of defined attenuated vaccine strains. PMID:15466524

  5. Expression, purification and preliminary X-ray analysis of the Neisseria meningitidis outer membrane protein PorB

    SciTech Connect

    Tanabe, Mikio; Iverson, Tina M.

    2010-01-28

    The Neisseria meningitidis outer membrane protein PorB was expressed in Escherichia coli and purified from inclusion bodies by denaturation in urea followed by refolding in buffered LDAO on a size-exclusion column. PorB has been crystallized in three different crystal forms: C222, R32 and P6{sub 3}. The C222 crystal form may contain either one or two PorB monomers in the asymmetric unit, while both the R32 and P6{sub 3} crystal forms contained one PorB monomer in the asymmetric unit. Of the three, the P6{sub 3} crystal form had the best diffraction quality, yielding data extending to 2.3 {angstrom} resolution.

  6. Application of POR-Tveks to the radiochemical recovery of yttrium-90

    SciTech Connect

    Maksimova, A.M.; Kvasnitskii, I.B.

    1988-01-01

    The authors describe a method for the radiochemical analysis of fish bones for the accumulation of strontium 90 and yttrium 90 from power plant contamination of surface waters which involves labelling the sample with isotopes and subsequent adsorption of the yttrium component with the use of POR-Tveks, an adsorbent based on a copolymer of styrene and divinylbenzene with heteroradical phosphine oxide. The yield of yttrium is determined from the mass of the oxide and from the half-life of the yttrium isotope.

  7. Antigenic topology of chlamydial PorB protein and identification of targets for immune neutralization of infectivity.

    PubMed

    Kawa, Diane E; Stephens, Richard S

    2002-05-15

    The outer membrane protein PorB is a conserved chlamydial protein that functions as a porin and is capable of eliciting neutralizing Abs. A topological antigenic map was developed using overlapping synthetic peptides representing the Chlamydia trachomatis PorB sequence and polyclonal immune sera. To identify which antigenic determinants were surface accessible, monospecific antisera were raised to the PorB peptides and were used in dot-blot and ELISA-based absorption studies with viable chlamydial elementary bodies (EBs). The ability of the surface-accessible antigenic determinants to direct neutralizing Ab responses was investigated using standardized in vitro neutralization assays. Four major antigenic clusters corresponding to Phe(34)-Leu(59) (B1-2 and B1-3), Asp(112) -Glu(145) (B2-3 and B2-4), Gly(179)-Ala(225) (B3-2 to B3-4), and Val(261)-Asn(305) (B4-4 to B5-2) were identified. Collectively, the EB absorption and dot-blot assays established that the immunoreactive PorB Ags were exposed on the surface of chlamydial EBs. Peptide-specific antisera raised to the surface-accessible Ags neutralized chlamydial infectivity and demonstrated cross-reactivity to synthetic peptides representing analogous C. pneumoniae PorB sequences. Furthermore, neutralization of chlamydial infectivity by C. trachomatis PorB antisera was inhibited by synthetic peptides representing the surface-exposed PorB antigenic determinants. These findings demonstrate that PorB Ags may be useful for development of chlamydial vaccines. PMID:11994474

  8. Multiple active site residues are important for photochemical efficiency in the light-activated enzyme protochlorophyllide oxidoreductase (POR).

    PubMed

    Menon, Binuraj R K; Hardman, Samantha J O; Scrutton, Nigel S; Heyes, Derren J

    2016-08-01

    Protochlorophyllide oxidoreductase (POR) catalyzes the light-driven reduction of protochlorophyllide (Pchlide), an essential, regulatory step in chlorophyll biosynthesis. The unique requirement of the enzyme for light has provided the opportunity to investigate how light energy can be harnessed to power biological catalysis and enzyme dynamics. Excited state interactions between the Pchlide molecule and the protein are known to drive the subsequent reaction chemistry. However, the structural features of POR and active site residues that are important for photochemistry and catalysis are currently unknown, because there is no crystal structure for POR. Here, we have used static and time-resolved spectroscopic measurements of a number of active site variants to study the role of a number of residues, which are located in the proposed NADPH/Pchlide binding site based on previous homology models, in the reaction mechanism of POR. Our findings, which are interpreted in the context of a new improved structural model, have identified several residues that are predicted to interact with the coenzyme or substrate. Several of the POR variants have a profound effect on the photochemistry, suggesting that multiple residues are important in stabilizing the excited state required for catalysis. Our work offers insight into how the POR active site geometry is finely tuned by multiple active site residues to support enzyme-mediated photochemistry and reduction of Pchlide, both of which are crucial to the existence of life on Earth. PMID:27285815

  9. Diagnóstico diferencial en la encefalitis por anticuerpos contra el receptor NMDA

    PubMed Central

    González-Valcárcel, J.; Rosenfeld, M.R.; Dalmau, J.

    2011-01-01

    Resumen Introducción La encefalitis por anticuerpos contra el receptor de NMDA (NMDAR) suele desarrollarse como un síndrome característico de evolución multifásica y diagnóstico diferencial amplio. Pacientes Presentamos a 2 pacientes diagnosticadas de encefalitis por anticuerpos NMDAR con un cuadro clínico típico, pero que inicialmente señaló otras etiologías. Discusión La afectación frecuente de pacientes jóvenes con manifestaciones psiquiátricas prominentes indica frecuentemente otras consideraciones diagnósticas; las más frecuentes son las encefalitis virales, los procesos psiquiátricos y el síndrome neuroléptico maligno. Varios síndromes previamente definidos de manera parcial o descriptiva en adultos y pacientes pediátricos probablemente eran casos de encefalitis anti-NMDAR. Conclusiones La encefalitis anti-NMDAR debe considerarse en pacientes jóvenes con manifestaciones psiquiátricas subagudas, movimientos anormales y alteraciones autonómicas. La caracterización clínica e inmunológica de esta enfermedad ha llevado a la identificación de nuevos anticuerpos que afectan a procesos de memoria, aprendizaje, conducta y psicosis. PMID:20964986

  10. Effect of SPM-based cleaning POR on EUV mask performance

    NASA Astrophysics Data System (ADS)

    Choi, Jaehyuck; Lee, Han-shin; Yoon, Jinsang; Shimomura, Takeya; Friz, Alex; Montgomery, Cecilia; Ma, Andy; Goodwin, Frank; Kang, Daehyuk; Chung, Paul; Shin, Inkyun; Cho, H.

    2011-11-01

    EUV masks include many different layers of various materials rarely used in optical masks, and each layer of material has a particular role in enhancing the performance of EUV lithography. Therefore, it is crucial to understand how the mask quality and patterning performance can change during mask fabrication, EUV exposure, maintenance cleaning, shipping, or storage. The fact that a pellicle is not used to protect the mask surface in EUV lithography suggests that EUV masks may have to undergo more cleaning cycles during their lifetime. More frequent cleaning, combined with the adoption of new materials for EUV masks, necessitates that mask manufacturers closely examine the performance change of EUV masks during cleaning process. We have investigated EUV mask quality and patterning performance during 30 cycles of Samsung's EUV mask SPM-based cleaning and 20 cycles of SEMATECH ADT exposure. We have observed that the quality and patterning performance of EUV masks does not significantly change during these processes except mask pattern CD change. To resolve this issue, we have developed an acid-free cleaning POR and substantially improved EUV mask film loss compared to the SPM-based cleaning POR.

  11. Methodology for obtaining stakeholder assessments of obesity policy options in the PorGrow project.

    PubMed

    Stirling, A; Lobstein, T; Millstone, E

    2007-05-01

    The Policy Options for Responding to the Growing Challenge of Obesity Research Project (PorGrow) study provided a unique opportunity to develop a large-scale application of a semi-quantitative technique for exploring interviewees' views on options to tackle obesity, using multi-criteria mapping. This 'heuristic' approach utilizes the advantages of a structured interviews framework by predefining a set of options for appraisal, while leaving interviewees free to select their own criteria for making their judgements. Additional information can be gleaned from the interview transcripts and related materials to set the appraisals in their policy context, and allowing interviewees to express their views on the options presented and their own appraisals. The PorGrow study team agreed a predefined set of 20 options for appraisal, and interviewed sets of stakeholders representing more than 20 aspects of policy development in each of the nine participating countries. The details of the methodology adopted are set out in this paper. PMID:17371304

  12. Effects of heme precursors on CYP1A2 and POR expression in the baculovirus/Spodoptera frugiperda system☆

    PubMed Central

    Lu, Huiyuan; Ma, Jun; Liu, Nian; Wang, Shoulin

    2010-01-01

    Objective CYP1A2 and NADPH-CYP450 oxidoreductase (POR) were expressed in the baculovirus/Spodoptera frugiperda (sf9) system. The aim of this study was to investigate the effects of heme precursors on the expression of CYP1A2 and POR. Methods The heme precursors [δ-Aminolaevulinic Acid (5-ALA), Fe3+ and hemin] were introduced into the system to evaluate their effects on the expression of CYP1A2, POR and their co-expression. All the proteins were identified using immunoblotting, CO-difference spectroscopy, or cytochrome c assay. Results In the present study, functional CYP1A2 and POR were successfully expressed in the baculovirus/sf9 system, and both of them showed high activities. Co-addition of 5-ALA and Fe3+ significantly improved expression of CYP1A2 by about 50% compared with the addition of 5-ALA, Fe3+ or hemin alone. Either co-addition of 5-ALA and Fe3+ or addition of 5-ALA or Fe3+ alone improved the POR expression level 2 fold and its activity 7-10 fold compared with control (no addition). However, unlike CYP1A2, there was no difference between the co-addition and addition of these heme precursors alone. Different ratios of BvCYP1A2 to BvPOR also affected the co-expression of CYP1A2 and POR, with a 3:1 ratio of BvCYP1A2 / BvPOR significantly increasing their co-expression. Surprisingly, the addition of 0.1 mM 5-ALA or Fe3+ alone, but not their co-addition, could significantly improve the CYP1A2 and POR co-expression (P < 0.05). Conclusion 5-ALA and Fe3+ increased the expression of CYP1A2 and POR in a baculovirus/sf9 system, but the pattern of their expression was different between their expression alone and co-expression. PMID:23554636

  13. Geometry sensing through POR1 regulates Rac1 activity controlling early osteoblast differentiation in response to nanofiber diameter.

    PubMed

    Higgins, A M; Banik, B L; Brown, J L

    2015-02-01

    Bone grafting procedures in the United States rely heavily upon autografts and allografts, which are donor-dependent, cause donor site pain, and can transmit disease. Synthetic bone grafts can reduce these risks; however, synthetics lack the bone differentiating (osteoinductive) abilities of auto- and allografts. Achieving innate osteoinductive properties of synthetics through surface modifications is currently under investigation. This study focuses on nanofibers, with emphasis on how fiber diameter and the potential curvature sensor POR1 affect the activation of the signaling molecules Rac1 and Arf1, and leading to expression of alkaline phosphatase (ALP), an osteoinductive marker. Diameters of 0.1, 0.3, and 1.0 μm were compared against a flat control. The highest level of Rac1 activation was achieved on the smallest fibers (0.1 μm), a trend that was lost in POR1 knockdowns. This supports the hypothesis that on small nanofibers, POR1 favorably binds to highly curved cell membranes, which allows Rac1 to subsequently dissociate and activate. When the curvature is insufficient to bind POR1, POR1 binds to inactive Rac1 and competitively inhibits its activation. Arf1 activation followed an opposite trend, with the largest nanofibers exhibiting the highest activity. This trend reinforces the known interaction between Rac1 and Arf1 through the GIT-PIX complex, an Arf1 GAP and Rac1 GEF, respectively. Large, (1.0 μm), nanofibers demonstrated the highest ALP activity, indicating that ALP expression is inversely dependent on Rac1 activation. Knockdown of POR1 resulted in increased ALP activity across the substrates but without regard to the curvature sensing trend seen previously. Thus, POR1 senses curvature and increases Rac1 activity, which negatively regulates bone differentiation. PMID:25539497

  14. Substrate-specific modulation of CYP3A4 activity by genetic variants of cytochrome P450 oxidoreductase (POR)

    PubMed Central

    Agrawal, Vishal; Choi, Ji Ha; Giacomini, Kathleen M.; Miller, Walter L.

    2010-01-01

    Objectives CYP3A4 receives electrons from P450 oxidoreductase (POR) to metabolize about 50% of clinically used drugs. There is substantial inter-individual variation in CYP3A4 catalytic activity that is not explained by CYP3A4 genetic variants. CYP3A4 is flexible and distensible, permitting it to accommodate substrates varying in shape and size. To elucidate mechanisms of variability in CYP3A4 catalysis, we examined the effects of genetic variants of POR, and explored the possibility that substrate-induced conformational changes in CYP3A4 differentially affect the ability of POR variants to support catalysis. Methods We expressed human CYP3A4 and four POR variants (Q153R, A287P, R457H, A503V) in bacteria, reconstituted them in vitro and measured the Michaelis constant and maximum velocity with testosterone, midazolam, quinidine and erythromycin as substrates. Results POR A287P and R457H had low activity with all substrates; Q153R had 76–94% of wild type (WT) activity with midazolam and erythromycin, but 129–150% activity with testosterone and quinidine. The A503V polymorphism reduced CYP3A4 activity to 61–77% of wild type with testosterone and midazolam, but had nearly wild type activity with quinidine and erythromycin. Conclusion POR variants affect CYP3A4 activities. The impact of a POR variant on catalysis by CYP3A4 is substrate-specific, probably due to substrate-induced conformational changes in CYP3A4. PMID:20697309

  15. Intermitência alfvênica gerada por caos na atmosfera solar e no vento solar

    NASA Astrophysics Data System (ADS)

    Rempel, E. L.; Chian, A. C.-L.; Macau, E. E. N.; Rosa, R. R.

    2003-08-01

    Dados medidos no vento solar rápido proveniente dos buracos coronais revelam que os plasmas no meio interplanetário são dominados por flutuações Alfvênicas, caracterizadas por uma alta correlação entre as variações do campo magnético e da velocidade do plasma. As flutuações exibem muitas características esperadas em turbulência magneto-hidrodinâmica totalmente desenvolvida, tais como intermitência e espectros contínuos. Contudo, os mecanismos responsáveis pela evolução de turbulência Alfvênica intermitente não são completamente compreendidos. Neste trabalho a teoria de caos é usada para explicar como sistemas Alfvênicos, modelados pela equação Schrödinger não-linear derivativa e pela equação Kuramoto-Sivashinsky, podem se tornar fortemente caóticos à medida em que parâmetros do plasma são variados. Pequenas perturbações no parâmetro de dissipação podem fazer com que o sistema mude bruscamente de um regime periódico, ou fracamente caótico, para um regime fortemente caótico. As séries temporais das flutuações do campo magnético nos regimes fortemente caóticos exibem comportamento intermitente, em que fases laminares ou fracamente caóticas são interrompidas por fortes estouros caóticos. É mostrado que o regime fortemente caótico é atingido quando as soluções periódicas ou fracamente caóticas globalmente estáveis interagem com soluções do sistema que são fortemente caóticas, mas globalmente instáveis. Estas soluções globalmente instáveis são conjuntos caóticos não-atrativos conhecidos como selas caóticas, e são responsáveis pelos fortes estouros nos regimes intermitentes. Selas caóticas têm sido detectadas experimentalmente em uma grande variedade de sistemas, sendo provável que elas desempenhem um papel importante na turbulência intermitente observada em plasmas espaciais.

  16. Fabrication of por-Si/SnO{sub x} nanocomposite layers for gas microsensors and nanosensors

    SciTech Connect

    Bolotov, V. V. Korusenko, P. M.; Nesov, S. N.; Povoroznyuk, S. N.; Roslikov, V. E.; Kurdyukova, E. A.; Sten'kin, Yu. A.; Shelyagin, R. V.; Knyazev, E. V.; Kan, V. E.; Ponomareva, I. V.

    2011-05-15

    Two-phase nanocomposite layers based on porous silicon and nonstoichiometric tin oxide were fabricated by various methods. The structure, as well as elemental and phase composition, of the obtained nanocomposites were studied using transmission and scanning electron microscopy, Raman spectroscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy. The results obtained confirm the formation of nanocomposite layers with a thickness as large as 2 {mu}m thick and SnO{sub x} stoichiometry coefficients x = 1.0-2.0. Significant tin diffusion into the porous silicon matrix with D{sub eff} Almost-Equal-To 10{sup -14} cm{sup 2} s{sup -1} was observed upon annealing at 770 K. Test sensor structures based on por-Si/SnO{sub x} nanocomposite layers grown by magnetron deposition showed fairly high stability of properties and sensitivity to NO{sub 2}.

  17. Recovery of naphthalene during evaporative concentration. [Tenax; XAD-2; POR-Q, XE-340

    SciTech Connect

    Higgins, C.E.; Guerin, M.R.

    1980-10-01

    The analysis of trace organics usually requires concentrating organic extracts to small volumes prior to instrumental analysis. The use of a concentration apparatus employing a nitrogen blanket and reduced pressure is desirable because the inert atmosphere and low temperature help to ensure stable composition. Unfortunately, diaromatic compounds such as the naphthalenes and biphenyls are frequently almost completely lost during the concentration step. Even under carefully controlled conditions only 26 +- 11% of the naphthalene is recovered. By placing a sorbent either in or downstream of the evaporation concentration flask, recovery of diaromatic compounds can be improved significantly. In this investigation, the following sorbents, Tenax, XAD-2, POR-Q, and XE-340 were tested. Recoveries with and without the use of sorbents, effects of solute concentration, purge time after solvent removal, and type of solvent used are reported here.

  18. Using the PORS Problems to Examine Evolutionary Optimization of Multiscale Systems

    SciTech Connect

    Reinhart, Zachary; Molian, Vaelan; Bryden, Kenneth

    2013-01-01

    Nearly all systems of practical interest are composed of parts assembled across multiple scales. For example, an agrodynamic system is composed of flora and fauna on one scale; soil types, slope, and water runoff on another scale; and management practice and yield on another scale. Or consider an advanced coal-fired power plant: combustion and pollutant formation occurs on one scale, the plant components on another scale, and the overall performance of the power system is measured on another. In spite of this, there are few practical tools for the optimization of multiscale systems. This paper examines multiscale optimization of systems composed of discrete elements using the plus-one-recall-store (PORS) problem as a test case or study problem for multiscale systems. From this study, it is found that by recognizing the constraints and patterns present in discrete multiscale systems, the solution time can be significantly reduced and much more complex problems can be optimized.

  19. Display of a PorA peptide from Neisseria meningitidis on the bacteriophage T4 capsid surface.

    PubMed Central

    Jiang, J; Abu-Shilbayeh, L; Rao, V B

    1997-01-01

    The exterior of bacteriophage T4 capsid is coated with two outer capsid proteins, Hoc (highly antigenic outer capsid protein; molecular mass, 40 kDa) and Soc (small outer capsid protein; molecular mass, 9 kDa), at symmetrical positions on the icosahedron (160 copies of Hoc and 960 copies of Soc per capsid particle). Both these proteins are nonessential for phage infectivity and viability and assemble onto the capsid surface after completion of capsid assembly. We developed a phage display system which allowed in-frame fusions of foreign DNA at a unique cloning site in the 5' end of hoc or soc. A DNA fragment corresponding to the 36-amino-acid PorA peptide from Neisseria meningitidis was cloned into the display vectors to generate fusions at the N terminus of Hoc or Soc. The PorA-Hoc and PorA-Soc fusion proteins retained the ability to bind to the capsid surface, and the bound peptide was displayed in an accessible form as shown by its reactivity with specific monoclonal antibodies in an enzyme-linked immunosorbent assay. By employing T4 genetic strategies, we show that more than one subtype-specific PorA peptide can be displayed on the capsid surface and that the peptide can also be displayed on a DNA-free empty capsid. Both the PorA-Hoc and PorA-Soc recombinant phages are highly immunogenic in mice and elicit strong antipeptide antibody titers even with a weak adjuvant such as Alhydrogel or no adjuvant at all. The data suggest that the phage T4 hoc-soc system is an attractive system for display of peptides on an icosahedral capsid surface and may emerge as a powerful system for construction of the next generation multicomponent vaccines. PMID:9353063

  20. Rescue of cytochrome P450 oxidoreductase (Por) mouse mutants reveals functions in vasculogenesis, brain and limb patterning linked to retinoic acid homeostasis.

    PubMed

    Ribes, Vanessa; Otto, Diana M E; Dickmann, Leslie; Schmidt, Katy; Schuhbaur, Brigitte; Henderson, Colin; Blomhoff, Rune; Wolf, C Roland; Tickle, Cheryll; Dollé, Pascal

    2007-03-01

    Cytochrome P450 oxidoreductase (POR) acts as an electron donor for all cytochrome P450 enzymes. Knockout mouse Por(-/-) mutants, which are early embryonic (E9.5) lethal, have been found to have overall elevated retinoic acid (RA) levels, leading to the idea that POR early developmental function is mainly linked to the activity of the CYP26 RA-metabolizing enzymes (Otto et al., Mol. Cell. Biol. 23, 6103-6116). By crossing Por mutants with a RA-reporter lacZ transgene, we show that Por(-/-) embryos exhibit both elevated and ectopic RA signaling activity e.g. in cephalic and caudal tissues. Two strategies were used to functionally demonstrate that decreasing retinoid levels can reverse Por(-/-) phenotypic defects, (i) by culturing Por(-/-) embryos in defined serum-free medium, and (ii) by generating compound mutants defective in RA synthesis due to haploinsufficiency of the retinaldehyde dehydrogenase 2 (Raldh2) gene. Both approaches clearly improved the Por(-/-) early phenotype, the latter allowing mutants to be recovered up until E13.5. Abnormal brain patterning, with posteriorization of hindbrain cell fates and defective mid- and forebrain development and vascular defects were rescued in E9.5 Por(-/-) embryos. E13.5 Por(-/-); Raldh2(+/-) embryos exhibited abdominal/caudal and limb defects that strikingly phenocopy those of Cyp26a1(-/-) and Cyp26b1(-/-) mutants, respectively. Por(-/-); Raldh2(+/-) limb buds were truncated and proximalized and the anterior-posterior patterning system was not established. Thus, POR function is indispensable for the proper regulation of RA levels and tissue distribution not only during early embryonic development but also in later morphogenesis and molecular patterning of the brain, abdominal/caudal region and limbs. PMID:17126317

  1. Global Microlending in Education Reform: Enseñá Por Argentina and the Neoliberalization of the Grassroots

    ERIC Educational Resources Information Center

    Friedrich, Daniel S.

    2010-01-01

    This article examines the workings and underlying assumptions behind Enseñá por Argentina (Teach for Argentina), one specific program that takes part in the larger and expanding network of Teach for All, by thinking about the ways in which a global push for redefining teaching and teacher education encounters local characteristics and histories,…

  2. [Professor Frantisek Por MD and Professor Robert Klopstock MD, students at Budapest and Prague Faculties of Medicine].

    PubMed

    Mydlík, M; Derzsiová, K

    2010-11-01

    Professor Frantisek Por MD and Professor Robert Klopstock MD were contemporaries, both born in 1899, one in Zvolen, the other in Dombovar, at the time of Austro-Hungarian Monarchy. Prof. Por attended the Faculty of Medicine in Budapest from 1918 to 1920, and Prof. Klopstock studied at the same place between 1917 and 1919. From 1920 until graduation on 6th February 1926, Prof. Por continued his studies at the German Faculty of Medicine, Charles University in Prague. Prof. Klopstock had to interrupt his studies in Budapest due to pulmonary tuberculosis; he received treatment at Tatranske Matliare where he befriended Franz Kafka. Later, upon Kafka's encouragement, he changed institutions and continued his studies at the German Faculty of Medicine, Charles University in Prague, where he graduated the first great go. It is very likely that, during their studies in Budapest and Prague, both professors met repeatedly, even though their life paths later separated. Following his graduation, Prof. Por practiced as an internist in Prague, later in Slovakia, and from 1945 in Kosice. In 1961, he was awarded the title of university professor of internal medicine at the Faculty of Medicine, Pavol Jozef Safarik University in Kosice, where he practiced until his death in 1980. Prof. Klopstock continued his studies in Kiel and Berlin. After his graduation in 1933, he practiced in Berlin as a surgeon and in 1938 left for USA. In 1962, he was awarded the title of university professor of pulmonary surgery in NewYork, where he died in 1972. PMID:21250499

  3. Functional POR A503V is associated with the risk of bladder cancer in a Chinese population

    PubMed Central

    Xiao, Xue; Ma, Gaoxiang; Li, Shushu; Wang, Meilin; Liu, Nian; Ma, Lan; Zhang, Zhan; Chu, Haiyan; Zhang, Zhengdong; Wang, Shou-Lin

    2015-01-01

    Human cytochrome P450 oxidoreductase (POR) plays important roles in the metabolism of exogenous carcinogens and endogenous sterol hormones. However, few studies have explored the association between POR variants and the risk of bladder cancer. In this study, we first sequenced all 16 POR exons among 50 randomly selected controls, and found three variants, rs1135612, rs1057868 (A503V) and rs2228104, which were then assessed the relation to risk of bladder cancer in a case-control study of 1,050 bladder cancer cases and 1,404 cancer-free controls in a Chinese population. People with A503V TT genotype have a decreased risk of bladder cancer in a recessive model (TT vs. CC/CT, OR = 0.73, 95% CI = 0.57–0.93), which was more pronounced among elderly male, non-smoking, subjects. Especially, A503V TT genotype showed a protective effect in the invasive tumor stage. Functional analysis revealed that A503V activity decreased in cytochrome c reduction (50.5 units/mg vs. 135.4 units/mg), mitomycin C clearance (38.3% vs. 96.8%), and mitomycin C-induced colony formation (78.0 vs 34.3 colonies per dish). The results suggested that POR A503V might decrease the risk of bladder cancer by reducing its metabolic activity, and should be a potential biomarker for predicting the susceptibility to human bladder cancer. PMID:26123203

  4. Inversor Resonante de Tres Elementos L-LC con Caracteristica Cortocircuitable para Aplicaciones de Calentamiento por Induccion

    NASA Astrophysics Data System (ADS)

    Espi Huerta, Jose Miguel

    Los generadores de calentamiento por induccion son puentes inversores con carga resonante, cuya mision es basicamente crear una corriente sinusoidal de gran amplitud sobre la "bobina de caldeo", que forma parte del tanque resonante. En el interior de esta bobina se introduce la pieza que se desea calentar. EI campo magnetico creado induce corrientes superficiales (corrientes de Foucault) sobre la pieza, que producen su calentamiento. Los tanques resonantes (tambien llamados osciladores) utilizados en la actualidad son el resonante serie y el resonante paralelo. Aunque ya desde hace algun tiempo se vienen construyendo generadores de alta potencia basados en estos dos osciladores, el exito nunca ha. sido completo en ninguno de los dos casos. Tal y como se explica en la introduccion de esta memoria, los puentes inversores utilizados deben operar sobre una carga inductiva (corriente retrasada) para evitar el fenomeno de la recuperacion inversa de sus diodos y la consiguiente ruptura de los transistores. De la restriccion topologica anterior se deduce que el generador paralelo debe conmutar a frecuencias inferiores a la resonancia, y el serie a frecuencias superiores. A esta restriccion topologica hay que unir otra que es exclusiva del calentamiento por induccion: La corriente por la bobina de caldeo debe ser sinusoidal. De no ser asi, resultaria imposible disponer toda la potencia de calentamiento sobre la pieza en el espesor requerido por la aplicacion. Como consecuencia, los inversores no pueden operar por debajo de la frecuencia de resonancia del oscilador, pues en ese caso se amplifican los armonicos de orden superior de la tension/corriente de entrada situados sobre la resonancia, con la consiguiente distorsion de la corriente de salida. La conjuncion de las dos restricciones anteriores obligan al inversor paralelo a funcionar a la frecuencia de resonancia del oscilador. Esto imposibilita un control por variacion de frecuencia, regulandose la potencia desde la

  5. Encefalitis por anticuerpos contra el receptor de NMDA: experiencia con seis pacientes pediátricos. Potencial eficacia del metotrexato

    PubMed Central

    Bravo-Oro, Antonio; Abud-Mendoza, Carlos; Quezada-Corona, Arturo; Dalmau, Josep; Campos-Guevara, Verónica

    2016-01-01

    Introducción La encefalitis por anticuerpos contra el receptor de N-metil-D-aspartato (NMDA) es una entidad cada vez más diagnosticada en edad pediátrica. A diferencia de los adultos, en muchos casos no se asocia a tumores y las manifestaciones iniciales en niños más frecuentes son crisis convulsivas y trastornos del movimiento, mientras que en los adultos predominan las alteraciones psiquiátricas. Casos clínicos Presentamos seis casos pediátricos confirmados con anticuerpos contra la subunidad NR1 del receptor de NMDA en suero y líquido cefalorraquídeo. Cinco de los casos comenzaron con crisis convulsivas como manifestación clínica inicial antes de desarrollar el cuadro clásico de esta entidad. En todos los casos se utilizaron esteroides como primera línea de tratamiento, con los que sólo se observó control de las manifestaciones en uno, por lo que el resto de los pacientes requirió inmunomoduladores de segunda línea. Todos los pacientes recibieron metotrexato como tratamiento inmunomodulador para evitar recaídas y la evolución fue a la mejoría en todos ellos. Conclusiones En nuestra serie de pacientes con encefalitis por anticuerpos contra el receptor de NMDA, ninguno se asoció a tumores. Todos los casos recibieron metotrexato por lo menos durante un año, no observamos eventos adversos clínicos ni por laboratorio, ni hubo secuelas neurológicas ni recaídas durante el tratamiento. Aunque es una serie pequeña y es deseable incrementar el número y tiempo de evolución, consideramos el metotrexato una excelente alternativa como tratamiento inmunomodulador para esta patología. PMID:24150952

  6. Prevalencia y tamizaje del Trastorno por Déficit de Atención con Hiperactividad en Costa Rica

    PubMed Central

    Weiss, Nicholas T.; Schuler, Jovita; Monge, Silvia; McGough, James J.; Chavira, Denise; Bagnarello, Monica; Herrera, Luis Diego; Mathews, Carol A.

    2015-01-01

    Resumen La investigación tuvo como propósito estimar la prevalencia del Trastorno por Déficit de Atención con Hiperactividad (TDAH) en Costa Rica y determinar si la versión en español del cuestionario Swanson Nolan and Pelham Scale IV (SNAP-IV) es un instrumento de tamizaje útil en una población de niños y niñas escolares costarricenses. El instrumento fue entregado a padres y maestros de 425 niños entre 5 y 13 años de edad (promedio = 8.8). Todos fueron evaluados con el instrumento Swanson, Kotkin, Agler, M-Flynn and Pelham Scale (SKAMP). Su diagnóstico fue confirmado con una entrevista clínica. La sensibilidad y la especificidad del SNAP-IV fueron evaluadas como predictores de criterios de diagnóstico según el DSM-IV. La prevalencia puntual en la muestra del TDAH fue del 5%. El tamizaje más preciso lo hizo el SNAP-IV completado por el maestro en un corte de 20%, con una sensibilidad de 96% y una especificidad de un 82%. La sensibilidad de los instrumentos completados por los padres fue más baja que aquella de los maestros. El SNAP-IV completado por las maestras con un corte aislando el 20% de los mayores puntajes categorizó correctamente a un 87% de los sujetos. PMID:22432094

  7. Targeting of Neisserial PorB to the mitochondrial outer membrane: an insight on the evolution of β-barrel protein assembly machines.

    PubMed

    Jiang, Jhih-Hang; Davies, John K; Lithgow, Trevor; Strugnell, Richard A; Gabriel, Kipros

    2011-11-01

    Mitochondria originated from Gram-negative bacteria through endosymbiosis. In modern day mitochondria, the Sorting and Assembly Machinery (SAM) is responsible for eukaryotic β-barrel protein assembly in the mitochondrial outer membrane. The SAM is the functional equivalent of the β-barrel assembly machinery found in the outer membrane of Gram-negative bacteria. In this study we examined the import pathway of a pathogenic bacterial protein, PorB, which is targeted from pathogenic Neisseria to the host mitochondria. We have developed a new method for measurement of PorB assembly into mitochondria that relies on the mobility shift exhibited by bacterial β-barrel proteins once folded and separated under semi-native electrophoretic conditions. We show that PorB is targeted to the outer mitochondrial membrane with a dependence on the intermembrane space shuttling chaperones and the core component of the SAM, Sam50, which is a functional homologue of BamA that is required for PorB assembly in bacteria. The peripheral subunits of the SAM, Sam35 and Sam37, which are essential for eukaryotic β-barrel protein assembly but do not have distinguishable functional homologues in bacteria, are not required for PorB assembly in eukaryotes. This shows that PorB uses an evolutionary conserved 'bacterial like' mechanism to infiltrate the host mitochondrial outer membrane. PMID:22032638

  8. Epitope specificity of murine and human bactericidal antibodies against PorA P1.7,16 induced with experimental meningococcal group B vaccines.

    PubMed

    Rouppe van der Voort, E M; Kuipers, B; Brugghe, H F; van Unen, L M; Timmermans, H A; Hoogerhout, P; Poolman, J T

    1997-03-01

    Synthetic peptides derived from the predicted loops 1 and 4 of meningococcal PorA, sero-subtype P1.7,16, were used to study the epitope specificity of murine and human PorA P1.7,16 bactericidal antibodies. The predicted loops 1 and 4 are surface exposed and carry in their apices the sero-subtype epitopes P1.7 (loop 1) or P1.16 (loop 4), respectively. Peptides were synthesized as mono- and multimeric peptides. Murine monoclonal and polyclonal antibodies were induced with meningococcal whole cell preparations. Polyclonal antibodies were evoked in volunteers after one immunization with 50 micrograms or 100 micrograms protein of a hexavalent meningococcal PorA vesicle vaccine. The induction of PorA antibodies was determined in ELISA using purified PorA P1.7,16. The epitope specificity of anti-PorA antibodies for both murine and human antibodies could be demonstrated by direct peptide ELISA using overlapping multimeric peptides almost spanning the entire loops 1 or 4 of the protein. The capacity of peptides to inhibit the bactericidal activity of murine and human antibodies was investigated using meningococcal strain H44/76 (B:15:P1.7,16) as a target strain. Bactericidal activities could be inhibited with both monomeric and multimeric peptides derived from epitopes P1.7 and P1.16. PMID:9093834

  9. RELATIVE POTENCY BASED ON HEPATIC ENZYME INDUCTION PREDICTS IMMUNOSUPPRESSIVE EFFECT OF A MIXTURE OF POLYCHLORINATED DIBENZO-P-DIOXINS (PCDDS), DIBENZOFURANS (PCDFS) AND BIPHENYLS (PCBS)

    EPA Science Inventory

    ABSTRACT
    ). Mixture (MIX)-1 contained TCDD , 2,3,7,8-tetrachlorodibenzofuran (TCDF), 1,2,3,7,8-pentachlorodibenzofuran (1-PeCDF), 2,3,4,7,8-pentachlorodibenzofuran (4-PeCDF), and 1,2,3,4,6,7,8,9-octachlorodibenzofuran (OCDF). MIX-2 was prepared by adding PCBs to MIX-1, the P...

  10. Comparative ability of various PCBs, PCDFs, and TCDD to induce cytochrome P450 1A1 and 1A2 activity following 4 weeks of treatment (short communication)

    SciTech Connect

    De Vito, M.J.; Maier, W.E.; Diliberto, J.J.; Birnbaum, L.S.

    1993-01-01

    The toxic equivalency factors (TEF) have been proposed for dibenzo-p-dioxins, dibenzofurans and polychlorinated biphenyls (PCBs). The proposed TEFs, which are presently being evaluated in the authors' laboratory are currently used to estimate the potential health risk associated with exposure to complex mixtures containing these chemicals. Hepatic cytochrome P-450 1A1 and 1A2 activities were determined for all chemicals tested and compared to those from TCDD treated mice. These initial studies indicate that the interim TEFs for the dibenzofurans adequately predict the relative induction potency for these compounds. However, the TEFs proposed for the dioxin-like PCBs overestimate the potency of these compounds by factors of 10-10,000. The present study indicates that more experimental data is required before TEFs for PCBs are used in regulatory decision making.

  11. Pilot Survey of Levels of Polychlorinated Dibenzo-P-Dioxins (Pcdds), Polychlorinated Dibenzofurans (Pcdfs), Polychlorinated Biphenyls (PCB) and Mercury in Rural Soils of the U.S.

    EPA Science Inventory

    Cover of the Pilot Survey Soil Report EPA has released a final report entitled, Pilot Survey of Levels of Polychlorinated Dibenzo-p-dioxins, Polychl...

  12. Spatial patterns of chemical contamination (metals, PAHs, PCBs, PCDDs/PCDFS) in sediments of a non-industrialized but densely populated coral atoll/small island state (Bermuda).

    PubMed

    Jones, Ross J

    2011-06-01

    There is a recognized dearth of standard environmental quality data in the wider Caribbean area, especially on coral atolls/small island states. Extensive surveys of sediment contamination (n=109 samples) in Bermuda revealed a wide spectrum of environmental quality. Zinc and especially copper levels were elevated at some locations, associated with boating (antifouling paints and boatyard discharges). Mercury contamination was surprisingly prevalent, with total levels as high as 12mg kg(-1)DW, although methyl mercury levels were quite low. PAH, PCB and PCDD/PCDF contamination was detected a several hotspots associated with road run-off, a marine landfill, and a former US Naval annexe. NOAA sediment quality guidelines were exceeded at several locations, indicating biological effects are possible, or at some locations probable. Overall, and despite lack of industrialization, anthropogenic chemicals in sediments of the atoll presented a risk to benthic biodiversity at a number of hotspots suggesting a need for sediment management strategies. PMID:21549399

  13. Formation of dioxins (PCDDs/PCDFs) by dioxin-free fly ash as a catalyst and relation with several chlorine-sources.

    PubMed

    Takasuga, T; Makino, T; Tsubota, K; Takeda, N

    2000-01-01

    Simplified thermal formation experiments have been conducted using dioxin-free fly ash as a catalyst with many kinds of combustible samples such as newspaper, kerosene, paraffin, PE (polyethylene), PP (polypropylene) and PVC. Chlorine sources were PVC, NaCl and HCl. The combustion of samples containing chlorine in the absence of dioxin-free fly ash produced dioxins at a low level although HCl was present in the gas stream. On the other hand, the combustion of samples without chlorine with dioxin-free fly ash increased dioxins formation to a level around 10 times higher than that upon heating dioxin-free fly ash alone. This result is considered to be due to the presence of metal chloride in the fly ash and hydrocarbons in the gas stream. The combustion of samples containing either an organic or inorganic chlorine source or using a HCl stream with dioxin-free fly ash increased dioxin level dramatically. PMID:10739038

  14. Análise dos Conceitos Astronômicos Apresentados por Professores de Algumas Escolas Estaduais Brasileiras

    NASA Astrophysics Data System (ADS)

    Voelzke, Marcos Rincon; Gonzaga, Edson Pereira

    2011-12-01

    A razão para o desenvolvimento deste trabalho baseia-se no fato de que muitos professores da Educação Básica (EB) não lidam com conceitos relacionados à astronomia, e quando o fazem eles simplesmente seguem livros didáticos que podem conter erros conceituais. Como é de conhecimento geral a astronomia é um dos conteúdos a serem ensinados na EB fazendo parte dos Parâmetros Curriculares Nacionais e das Propostas Curriculares do Estado de São Paulo, mas é um fato, que vários pesquisadores apontam, a existência de muitos problemas no ensino da astronomia. Com o propósito de minimizar algumas dessas deficiências foi realizado um trabalho de pesquisa com a utilização de questionários pré e pós pesquisa, para tanto foi desenvolvido um Curso de Extensão Universitária para professores da Diretoria de Ensino Regional (DE) que abrange Mauá, Ribeirão Pires e Rio Grande da Serra (no Estado de São Paulo) com os seguintes objetivos: levantar concepções alternativas; subsidiar os professores por meio de palestras, debates e workshops, e verificar o sucesso da aprendizagem após o curso, adotando-se como referência, para a análise dos resultados, os dicionários de Língua Portuguesa (FERREIRA, 2004) e Enciclopédico de Astronomia e Astronáutica (MOURĀO, 1995). Portanto, dezesseis questões foram aplicadas antes e após o curso, assim pode-se verificar após a pesquisa que 100,0% dos professores sabiam os nomes das fases da Lua, 97,0% entenderam que o Sistema Solar é composto por oito planetas, 78,1% foram capazes de explicar como ocorre um eclipse lunar, um eclipse solar e um solstício, 72,7% sabiam como explicar a ocorrência das estações do ano; 64,5% explicaram corretamente a ocorrência do equinócio, 89,7% foram capazes de definir adequadamente o termo cometa; 63,6% definiram asteróide, 54,5% meteoro, 58,1% galáxia, e 42,4% planeta. Os resultados obtidos indicam uma aprendizagem significativa por parte dos participantes.

  15. Immunogenicity and reactogenicity in UK infants of a novel meningococcal vesicle vaccine containing multiple class 1 (PorA) outer membrane proteins.

    PubMed

    Cartwright, K; Morris, R; Rümke, H; Fox, A; Borrow, R; Begg, N; Richmond, P; Poolman, J

    1999-06-01

    The development of effective vaccines against serogroup B meningococci is of great public health importance. We assessed a novel genetically engineered vaccine containing six meningococcal class 1 (PorA) outer membrane proteins representing 80% of prevalent strains in the UK. 103 infants were given the meningococcal vaccine at ages 2, 3 and 4 months with routine infant immunisations, with a fourth dose at 12-18 months. The vaccine was well tolerated. Three doses evoked good immune responses to two of six meningococcal strains expressing PorA proteins contained in the vaccine. Following a fourth dose, larger bactericidal responses to all six strains were observed, suggesting that the initial course had primed memory lymphocytes and revaccination stimulated a booster response. This hexavalent PorA meningococcal vaccine was safe and evoked encouraging immune responses in infants. Vaccines of this type warrant further development and evaluation. PMID:10418910

  16. Crystallization and preliminary X-ray analysis of the C-terminal fragment of PorM, a subunit of the Porphyromonas gingivalis type IX secretion system.

    PubMed

    Stathopulos, Julien; Cambillau, Christian; Cascales, Eric; Roussel, Alain; Leone, Philippe

    2015-01-01

    PorM is a membrane protein involved in the assembly of the type IX secretion system (T9SS) from Porphyromonas gingivalis, a major bacterial pathogen responsible for periodontal disease in humans. The periplasmic domain of PorM was overexpressed in Escherichia coli and purified. A fragment of the purified protein was obtained by limited proteolysis. Crystals of this fragment belonged to the tetragonal space group P4(3)2(1)2. Native and MAD data sets were recorded to 2.85 and 3.1 Å resolution, respectively, using synchrotron radiation. PMID:25615973

  17. "Estudio tribologico de aceros para moldes. Aplicacion al moldeo por inyeccion de polibutilentereftalato reforzado con fibra de vidrio"

    NASA Astrophysics Data System (ADS)

    Martinez Mateo, Isidoro Jose

    Mould materials for injection moulding of polymers and polymer-matrix composites represent a relevant industrial economic sector due to the large quantity of pieces and components processed. The material selection for mould manufacturing, its composition and heat treatment, the hardening procedures and machining and finishing processes determine the service performance and life of the mould. In the first part of the present study, the relationship between the hardness and microstructure and the wear resistance of mould steels from large blocks has been studied by pin-on-disc tests, studying the main wear mechanisms. In order to determine the surface damage on mould steels under real injection conditions, different commercial steels have been studied by measuring the variation of surface roughness with the number of injected pieces with different reinforcement percentages and different mould geometries, by using optical profilometry and scanning electron microscopy techniques. It was important to determine the variation of surface roughness of the moulded pieces with the number of injection operations. The materials used were polybutyleneterephthalate pure and reinforced with either 20% or 50% glass fibre. For the different mould designs, the evolution of the glass fibre orientation with injection flow has been determined by image analysis and related to roughness changes and surface damage, both of the composite parts and of the mould steel surface. Finally, the abrasion resistance of the composite parts has been studied by scratch tests as a function of the number of injected parts and of the scratch direction with respect to injection flow and glass fibre orientation. Los materiales para moldes de inyeccion de polimeros y materiales compuestos representan un sector economicamente muy relevante debido al gran aumento del numero de componentes fabricados a partir de materiales polimericos obtenidos mediante moldeo por inyeccion. La seleccion del material para la

  18. P(O)R2-directed Pd-catalyzed C–H functionalization of biaryl derivatives to synthesize chiral phosphorous ligands

    PubMed Central

    Hu, Rong-Bin; Wang, Hong-Li; Zhang, Hong-Yu; Zhang, Heng; Ma, Yan-Na

    2014-01-01

    Summary Chiral phosphorus ligands have been widely used in transition metal-catalyzed asymmetric reactions. Herein, we report a new synthesis approach of chiral biaryls containing a phosphorus moiety using P(O)R2-directed Pd-catalyzed C–H activation; the functionalized products are produced with good enantioselectivity. PMID:25246966

  19. Adult Student Retention and Achievement with Language-Based Modular Materials. POR FIN: Program Organizing Related Family Instruction in the Neighborhood.

    ERIC Educational Resources Information Center

    Bexar County School Board, San Antonio, TX.

    The goal of the POR FIN research design was to develop a language-based curriculum emphasizing the audiolingual approach and integrating academic and social-functioning subject matter. The modular curriculum is designed so that each lesson is independent and complete in itself, and provides a high degree of motivation, retention, and achievement…

  20. Informe a la nación indica que los índices de muertes por cáncer siguen bajando

    Cancer.gov

    Los índices de mortalidad por todos los cánceres combinados para hombres, mujeres y niños siguieron bajando en Estados Unidos entre 2004 y 2008, según el Informe Anual a la Nación sobre el Estado del Cáncer de 1975 a 2008. El índice general de diagnóstico

  1. El proceso hacia la integracion de la equidad por genero al curriculo.(The Process of the Integration of Gender Equity in the Curriculum.)

    ERIC Educational Resources Information Center

    Rivera-Bermudez, Carmen D.

    "El Proyecto Colaborativo de Equidad por Genero en la Educacion," or the Collaborative Project for Gender Equity in Education, was undertaken in Puerto Rico between 1990 and 1992 to study how to facilitate the integration of gender equity themes in the curriculum through the direct action of participating teachers. A study examined the attitudes…

  2. Community-based education in nutrition and cancer: the Por La Vida Cuidándome curriculum.

    PubMed

    Navarro, A M; Rock, C L; McNicholas, L J; Senn, K L; Moreno, C

    2000-01-01

    The Por La Vida (PLV) intervention model relies on community lay health advisors trained to conduct education sessions among members of their existing social networks. PLV Cuidándome was funded by the NCI to develop, implement, and evaluate the PLV model with respect to nutrition and cancer prevention, as well as early detection of breast and cervical cancers. The target population is the Latino community, for which substantial barriers to health care access exist. This article presents the curriculum that guides the sessions and describes its development, which was based on semi-structured interviews with Latina lay-health community workers to explore relevant attitudes and behaviors. Also key to the process was the work of the educational materials committee, whose members offered community representation as well as expertise in nutritional sciences, educational technologies, and community-based health promotion interventions and research. The 12-session curriculum's goal was to increase both the variety and the quality of fruits and/or vegetables consumed. It included information about consumption of fiber and fat in the importance of balance between energy intake and physical activity. The program has been well received. An ongoing study examines how it enhances nutrition and cancer prevention. PMID:11019766

  3. Estimaciones de Prevalencia del VIH por Género y Grupo de Riesgo en Tijuana, México: 2006

    PubMed Central

    Iñiguez-Stevens, Esmeralda; Brouwer, Kimberly C.; Hogg, Robert S.; Patterson, Thomas L.; Lozada, Remedios; Magis-Rodriguez, Carlos; Elder, John P.; Viani, Rolando M.; Strathdee, Steffanie A.

    2010-01-01

    OBJETIVO Estimar la prevalencia del VIH en adultos de 15-49 años de edad en Tijuana, México - en la población general y en subgrupos de riesgo en el 2006. METODOS Se obtuvieron datos demográficos del censo Mexicano del 2005, y la prevalencia del VIH se obtuvo de la literatura. Se construyó un modelo de prevalencia del VIH para la población general y de acuerdo al género. El análisis de sensibilidad consistió en estimar errores estándar del promedio-ponderado de la prevalencia del VIH y tomar derivados parciales con respecto a cada parámetro. RESULTADOS La prevalencia del VIH es 0.54%(N = 4,347) (Rango: 0.22%–0.86%, (N = 1,750–6,944)). Esto sugiere que 0.85%(Rango: 0.39%–1.31%) de los hombres y 0.22%(Rango: 0.04%–0.40%) de las mujeres podrían ser VIH-positivos. Los hombres que tienen sexo con hombres (HSH), las trabajadoras sexuales usuarias de drogas inyectables (MTS-UDI), MTS-noUDI, mujeres UDI, y los hombres UDI contribuyeron las proporciones más elevadas de personas infectadas por el VIH. CONCLUSIONES El número de adultos VIH-positivos entre subgrupos de riesgo en la población de Tijuana es considerable, marcando la necesidad de enforcar las intervenciones de prevención en sus necesidades específicas. El presente modelo estima que hasta 1 en cada 116 adultos podrían ser VIH-positivos. PMID:19685824

  4. Study of the interaction mechanisms between absorbed NO{sub 2} and por-Si/SnO{sub x} nanocomposite layers

    SciTech Connect

    Bolotov, V. V.; Kan, V. E. Makushenko, R. K.; Biryukov, M. Yu.; Ivlev, K. E.; Roslikov, V. E.

    2013-10-15

    The interaction mechanisms between NO{sub 2} molecules and the surface of por-Si/SnO{sub x} nanocomposites obtained by magnetron deposition and chemical vapor deposition (CVD) are studied by infrared absorption spectroscopy and electron paramagnetic resonance methods. The observed increase in the free carrier concentration in the por-Si/SnO{sub x} nanocomposite layers is explained by a change in the charge state of P{sub b} centers due to the formation of neutral 'surface defect-adsorbed NO{sub 2} molecule' complexes with free carrier generation in the crystallite bulk. In the nanocomposite layers grown by the CVD method, the increase in the free hole concentration during NO{sub 2} adsorption is much less pronounced in comparison with the composite grown by magnetron deposition, which is caused by the competing interaction channel of NO{sub 2} molecules with electrically neutral P{sub b} centers.

  5. Los índices de mortalidad por cáncer de pulmón siguen en descenso y contribuyen a la continua reducc

    Cancer.gov

    El Informe Anual a la Nación sobre el Estado del Cáncer (1975 a 2010), mostró un descenso más acelerado que en años anteriores de los índices de mortalidad por cáncer de pulmón. También contiene una sección especial que destaca los efectos significativos

  6. La doctora Amelie Ramírez y la investigación de desigualdades de salud por cáncer en la comunidad la

    Cancer.gov

    La doctora Ramírez es la investigadora principal de Redes en Acción, un centro del programa de redes comunitarias subvencionado por el NCI que se propone reducir la incidencia del cáncer en la comunidad latina a través de una red nacional de grupos comunitarios, investigadores, agencias de salud gubernamentales y la población en general.

  7. Binding of Complement Factor H to PorB3 and NspA Enhances Resistance of Neisseria meningitidis to Anti-Factor H Binding Protein Bactericidal Activity

    PubMed Central

    Giuntini, Serena; Pajon, Rolando; Ram, Sanjay

    2015-01-01

    Among 25 serogroup B Neisseria meningitidis clinical isolates, we identified four (16%) with high factor H binding protein (FHbp) expression that were resistant to complement-mediated bactericidal activity of sera from mice immunized with recombinant FHbp vaccines. Two of the four isolates had evidence of human FH-dependent complement downregulation independent of FHbp. Since alternative complement pathway recruitment is critical for anti-FHbp bactericidal activity, we hypothesized that in these two isolates binding of FH to ligands other than FHbp contributes to anti-FHbp bactericidal resistance. Knocking out NspA, a known meningococcal FH ligand, converted both resistant isolates to anti-FHbp susceptible isolates. The addition of a nonbactericidal anti-NspA monoclonal antibody to the bactericidal reaction also increased anti-FHbp bactericidal activity. To identify a role for FH ligands other than NspA or FHbp in resistance, we created double NspA/FHbp knockout mutants. Mutants from both resistant isolates bound 10-fold more recombinant human FH domains 6 and 7 fused to Fc than double knockout mutants prepared from two sensitive meningococcal isolates. In light of recent studies showing functional FH-PorB2 interactions, we hypothesized that PorB3 from the resistant isolates recruited FH. Allelic exchange of porB3 from a resistant isolate to a sensitive isolate increased resistance of the sensitive isolate to anti-FHbp bactericidal activity (and vice versa). Thus, some PorB3 variants functionally bind human FH, which in the presence of NspA enhances anti-FHbp resistance. Combining anti-NspA antibodies with anti-FHbp antibodies can overcome resistance. Meningococcal vaccines that target both NspA and FHbp are likely to confer greater protection than either antigen alone. PMID:25644002

  8. Corynebacterium jeikeium jk0268 Constitutes for the 40 Amino Acid Long PorACj, Which Forms a Homooligomeric and Anion-Selective Cell Wall Channel

    PubMed Central

    Norouzy, Amir; Schulz, Robert; Nau, Werner M.; Kleinekathöfer, Ulrich; Tauch, Andreas; Benz, Roland

    2013-01-01

    Corynebacterium jeikeium, a resident of human skin, is often associated with multidrug resistant nosocomial infections in immunodepressed patients. C. jeikeium K411 belongs to mycolic acid-containing actinomycetes, the mycolata and contains a channel-forming protein as judged from reconstitution experiments with artificial lipid bilayer experiments. The channel-forming protein was present in detergent treated cell walls and in extracts of whole cells using organic solvents. A gene coding for a 40 amino acid long polypeptide possibly responsible for the pore-forming activity was identified in the known genome of C. jeikeium by its similar chromosomal localization to known porH and porA genes of other Corynebacterium strains. The gene jk0268 was expressed in a porin deficient Corynebacterium glutamicum strain. For purification temporarily histidine-tailed or with a GST-tag at the N-terminus, the homogeneous protein caused channel-forming activity with an average conductance of 1.25 nS in 1M KCl identical to the channels formed by the detergent extracts. Zero-current membrane potential measurements of the voltage dependent channel implied selectivity for anions. This preference is according to single-channel analysis caused by some excess of cationic charges located in the channel lumen formed by oligomeric alpha-helical wheels. The channel has a suggested diameter of 1.4 nm as judged from the permeability of different sized hydrated anions using the Renkin correction factor. Surprisingly, the genome of C. jeikeium contained only one gene coding for a cell wall channel of the PorA/PorH type found in other Corynebacterium species. The possible evolutionary relationship between the heterooligomeric channels formed by certain Corynebacterium strains and the homooligomeric pore of C. jeikeium is discussed. PMID:24116064

  9. Adjuvant Effects Elicited by Novel Oligosaccharide Variants of Detoxified Meningococcal Lipopolysaccharides on Neisseria meningitidis Recombinant PorA Protein: A Comparison in Mice

    PubMed Central

    Mehta, Ojas H.; Norheim, Gunnstein; Hoe, J . Claire; Rollier, Christine S.; Nagaputra, Jerry C.; Makepeace, Katherine; Saleem, Muhammad; Chan, Hannah; Ferguson, David J. P.; Jones, Claire; Sadarangani, Manish; Hood, Derek W.; Feavers, Ian; Derrick, Jeremy P.; Pollard, Andrew J.; Moxon, E . Richard

    2014-01-01

    Neisseria meningitidis lipopolysaccharide (LPS) has adjuvant properties that can be exploited to assist vaccine immunogenicity. The modified penta-acylated LPS retains the adjuvant properties of hexa-acylated LPS but has a reduced toxicity profile. In this study we investigated whether two modified glycoform structures (LgtE and IcsB) of detoxified penta-acylated LPS exhibited differential adjuvant properties when formulated as native outer membrane vesicles (nOMVs) as compared to the previously described LgtB variant. Detoxified penta-acylated LPS was obtained by disruption of the lpxL1 gene (LpxL1 LPS), and three different glycoforms were obtained by disruption of the lgtB, lgtE or icsB genes respectively. Mice (mus musculus) were immunized with a recombinant PorA P1.7-2,4 (rPorA) protein co-administered with different nOMVs (containing a different PorA serosubtype P1.7,16), each of which expressed one of the three penta-acylated LPS glycoforms. All nOMVs induced IgG responses against the rPorA, but the nOMVs containing the penta-acylated LgtB-LpxL1 LPS glycoform induced significantly greater bactericidal activity compared to the other nOMVs or when the adjuvant was Alhydrogel. Compared to LgtE or IcsB LPS glycoforms, these data support the use of nOMVs containing detoxified, modified LgtB-LpxL1 LPS as a potential adjuvant for future meningococcal protein vaccines. PMID:25545241

  10. Binding of complement factor H to PorB3 and NspA enhances resistance of Neisseria meningitidis to anti-factor H binding protein bactericidal activity.

    PubMed

    Giuntini, Serena; Pajon, Rolando; Ram, Sanjay; Granoff, Dan M

    2015-04-01

    Among 25 serogroup B Neisseria meningitidis clinical isolates, we identified four (16%) with high factor H binding protein (FHbp) expression that were resistant to complement-mediated bactericidal activity of sera from mice immunized with recombinant FHbp vaccines. Two of the four isolates had evidence of human FH-dependent complement downregulation independent of FHbp. Since alternative complement pathway recruitment is critical for anti-FHbp bactericidal activity, we hypothesized that in these two isolates binding of FH to ligands other than FHbp contributes to anti-FHbp bactericidal resistance. Knocking out NspA, a known meningococcal FH ligand, converted both resistant isolates to anti-FHbp susceptible isolates. The addition of a nonbactericidal anti-NspA monoclonal antibody to the bactericidal reaction also increased anti-FHbp bactericidal activity. To identify a role for FH ligands other than NspA or FHbp in resistance, we created double NspA/FHbp knockout mutants. Mutants from both resistant isolates bound 10-fold more recombinant human FH domains 6 and 7 fused to Fc than double knockout mutants prepared from two sensitive meningococcal isolates. In light of recent studies showing functional FH-PorB2 interactions, we hypothesized that PorB3 from the resistant isolates recruited FH. Allelic exchange of porB3 from a resistant isolate to a sensitive isolate increased resistance of the sensitive isolate to anti-FHbp bactericidal activity (and vice versa). Thus, some PorB3 variants functionally bind human FH, which in the presence of NspA enhances anti-FHbp resistance. Combining anti-NspA antibodies with anti-FHbp antibodies can overcome resistance. Meningococcal vaccines that target both NspA and FHbp are likely to confer greater protection than either antigen alone. PMID:25644002

  11. Immunogenicity studies with a genetically engineered hexavalent PorA and a wild-type meningococcal group B outer membrane vesicle vaccine in infant cynomolgus monkeys.

    PubMed

    Rouppe van der Voort, E; Schuller, M; Holst, J; de Vries, P; van der Ley, P; van den Dobbelsteen, G; Poolman, J

    2000-01-31

    The immunogenicity of two meningococcal outer membrane vesicle (OMV) vaccines, namely the Norwegian wild-type OMV vaccine and the Dutch hexavalent PorA OMV vaccine, were examined in infant cynomolgus monkeys. For the first time, a wild-type- and a recombinant OMV vaccine were compared. Furthermore, the induction of memory and the persistence of circulating antibodies were measured. The Norwegian vaccine contained all four classes of major outer membrane proteins (OMP) and wild-type L3/L8 lipopolysaccharide (LPS). The Dutch vaccine consisted for 90% of class 1 OMPs, had low expression of class 4 and 5 OMP, and GalE LPS. Three infant monkeys were immunised with a human dose at the age of 1.5, 2.5 and 4.5 months. Two monkeys of each group received a fourth dose at the age of 11 months. In ELISA, both OMV vaccines were immunogenic and induced booster responses, particularly after the fourth immunisation. The Norwegian vaccine mostly induced sero-subtype P1.7,16 specific serum bactericidal antibodies (SBA), although some other SBA were induced as well. The antibody responses against P1.7,16, induced by the Norwegian vaccine, were generally higher than for the Dutch vaccine. However, the Dutch vaccine induced PorA specific SBA against all six sero-subtypes included in the vaccine showing differences in the magnitude of SBA responses to the various PorAs. PMID:10618530

  12. Obtención de la curva de luz en la ocultación de 35 Sgr por Júpiter el 6 de marzo de 1996

    NASA Astrophysics Data System (ADS)

    Paolantonio, S.; Duffard, R.; Carranza, G.

    La ocultación de la estrella de quinta magnitud 35 Sgr por Júpiter, se produjo el 6 de Marzo de 1996 a las 13 hs. TU. El objetivo era medir el cambio del flujo de la estrella en el ingreso y egreso por el limbo del planeta. Con estos datos se pueden determinar parámetros físicos del planeta (radio, eccentricidad) y de su atmósfera (escala de altura, temperatura, densidad, presión) Para lograr ésto se programó la cámara CCD TH 7896 1024 x 1025 instalada en el telescopio de 1.54 m de Bosque Alegre con el objetivo de lograr 2 imágenes por segundo. De esta forma se obtuvieron 2100 imágenes de la inmersión y otras tantas de la emersión. Hubo que tener grandes precauciones para evitar la saturación del CCD ya que la observación se realizó de día. En este momento las imágenes se encuentran en el Department of Planetary Sciences, Lunar and Planetary Laboratory, University of Arizona, para su reducción.

  13. Astronomy in the Classroom: Why? (Spanish Title: Astronomía en la Clase: ¿Por Qué?) Astronomia na Sala de Aula: Por Quê?

    NASA Astrophysics Data System (ADS)

    Daros Gama, Leandro; Bagdonas Henrique, Alexandre

    2010-07-01

    There are many discussions about the relevance of the topics covered in classes. One subject in particular is the focus of this essay: astronomy. In what sense and to what extent it would be worth to teach it in science or other kind of classes? In this paper we discuss some aspects of the advantages of dealing with this area of knowledge in schools, taking into account the epistemological and axiological dimensions of astronomy, in light of the vision of science as an intelligent dialogue with the world (Bachelard), in addition to the "problematization" knowledge of Paulo Freire. We propose that in fact the Astronomy does not need to be seen as just a new set of contents to be taught, but appears as a set of motivational contents for historical-philosophical discussions, and permit the discussion of concepts of other disciplines. Numerosas discusiones se están llevando a cabo acerca de la pertinencia de los temas tradicionalmente tratados en las clases. Uno de los temas, en particular, es el foco de este ensayo: la astronomía. ¿En qué sentido y en qué medida sería conveniente tratarla en clase, ya sea en clases de ciencias naturales, específicamente en las de astronomía o asignaturas afines? Elaboramos en este artículo algunos aspectos de las ventajas de tratar esta área del conocimiento en las escuelas, teniendo en cuenta las dimensiones epistemológica y axiológica de la astronomía, a la luz de la visión de la ciencia como un diálogo inteligente con el mundo (Bachelard), además de la propuesta del conocimiento "problematizador" de Paulo Freire. Proponemos que en realidad la astronomía no tiene por qué ser vista sólo como un nuevo conjunto de contenidos que se enseñan, sino que aparece como un conjunto de temas de motivación para el debate histórico-filosófico y para permitir la discusión de los conceptos típicos de otras disciplinas. Muitas discussões vêm acontecendo sobre a relevância dos temas abordados em sala de aula. Um tema, em

  14. Pincharse sin infectarse: estrategias para prevenir la infección por el VIH y el VHC entre usuarios de drogas inyectables

    PubMed Central

    MATEU-GELABERT, P.; FRIEDMAN, S.; SANDOVAL, M.

    2011-01-01

    Resumen Objetivo Desde principios de los noventa, en la ciudad de Nueva York se han implementado con éxito programas para reducir la incidencia del virus de la inmunodeficiencia humana (VIH) y, en menor medida, del virus de la hepatitis C (VHC). A pesar de ello, aproximadamente el 70% de los usuario de drogas inyectables (UDI) están infectados por el VHC. Queremos investigar cómo el 30% restante se las ha arreglado para no infectarse. El Staying safe (nombre original del estudio) explora los comportamientos y mecanismos que ayudan a evitar la infección por el VHC y el VIH a largo plazo. Material y métodos Hemos utilizado el concepto de «desviación positiva» aplicado en otros campos de salud pública. Estudiamos las estrategias, prácticas y tácticas de prevención de aquellos UDI que, viviendo en contextos de alta prevalencia, se mantienen sin infectar por VIH y el VHC, a pesar de haberse inyectado heroína durante años. Los resultados preliminares presentados en este artículo incluyen el análisis de las entrevistas realizadas a 25 UDI (17 doble negativos, 3 doble positivos y 5 con infección por el VHC y sin infección por el VIH). Se usaron entrevistas semiestructuradas que exploraban con detalle la historia de vida de los sujetos, incluyendo su consumo de drogas, redes sociales, contacto con instituciones, relaciones sexuales y estrategias de protección y vigilancia. Resultados La intencionalidad es importante para no infectarse, especialmente durante períodos de involución (períodos donde hay un deterioro económico y/o social que llevan al que se inyecta a situaciones de mayor riesgo). Presentamos tres dimensiones independientes de intencionalidad que conllevan comportamientos que pueden ayudar a prevenir la infección: a) evitar «el mono» (síntomas de abstención) asegurando el acceso a la droga; b) «llevarlo bien» para no convertirse en un junkie y así evitar la «muerte social» y la falta de acceso a los recursos, y c) seguir sin

  15. [Ag20 {S2 P(OR)2 }12 ]: A Superatom Complex with a Chiral Metallic Core and High Potential for Isomerism.

    PubMed

    Dhayal, Rajendra S; Lin, Yan-Ru; Liao, Jian-Hong; Chen, Yuan-Jang; Liu, Yu-Chiao; Chiang, Ming-Hsi; Kahlal, Samia; Saillard, Jean-Yves; Liu, C W

    2016-07-11

    The synthesis and structural determination of a silver nanocluster [Ag20 {S2 P(OiPr)2 }12 ] (2), which contains an intrinsic chiral metallic core, is produced by reduction of one silver ion from the eight-electron superatom complex [Ag21 {S2 P(OiPr)2 }12 ](PF6 ) (1) by borohydrides. Single-crystal X-ray analysis displays an Ag20 core of pseudo C3 symmetry comprising a silver-centered Ag13 icosahedron capped by seven silver atoms. Its n-propyl derivative, [Ag20 {S2 P(OnPr)2 }12 ] (3), can also be prepared by the treatment of silver(I) salts and dithiophosphates in a stoichiometric ratio in the presence of excess amount of [BH4 ](-) . Crystal structure analyses reveal that the capping silver-atom positions relative to their icosahedral core are distinctly different in 2 and 3 and generate isomeric, chiral Ag20 cores. Both Ag20 clusters display an emission maximum in the near IR region. DFT calculations are consistent with a description within the superatom model of an 8-electron [Ag13 ](5+) core protected by a [Ag7 {S2 P(OR)2 }12 ](5-) external shell. Two additional structural variations are predicted by DFT, showing the potential for isomerism in such [Ag20 {S2 P(OR)2 }12 ] species. PMID:27189869

  16. A survey of homopteran species (Auchenorrhyncha) from coffee shrubs and poró and laurel trees in shaded coffee plantations, in Turrialba, Costa Rica.

    PubMed

    Rojas, L; Godoy, C; Hanson, P; Hilje, L

    2001-01-01

    A survey of homopteran species (Auchenorryncha) was conducted in coffee plantations with no shade (C), and in those with shade of either poró (Erythrina poeppigiana) (CP) or poró plus laurel (Cordia alliodora) (CPL), in Turrialba, Costa Rica. A total of 130 species in ten families were collected, dominated by Cicadellidae (82 species). Species richness was highest in the CP system (88), followed by CPL (74) and C systems (60). Five most common species for all systems were Fusigonalia lativittata, Hebralebra nicaraguensis, Neocoelidia sp., Oliarus sp. and Clastoptera sp. Diversification of the coffee agroecosystem favors some species while limiting others, and have no effect on the majority of species. Thus, only F. lativittata, Neocoelidia sp. and Scaphytopius ca. latidens were well represented in all systems, but were more abundant in coffee shrubs. Additionally, the following were the dominant species in each system: Graphocephala sp. 1 (C), F. lativittata (CP) and H. nicaraguensis (CPL). Four species abundant on laurel trees, including H. nicaraguensis, appeared almost exclusively on these tree species. Species similarity was highest on the CP and CPL systems (51% of the species in common), followed by the C and CP (39%) and the C and CPL systems (38%). These findings show that even disturbed systems can harbor many insect species, so that they deserve attention from conservation advocates and biologists. PMID:12189787

  17. DEVELOPMENT OF A REFINED DATABASE OF RELATIVE POTENCY ESTIMATES TO FACILITATE BETTER CHARACTERIZATION OF VARIABILITY AND UNCERTAINTY IN THE CURRENT MAMMALIAN TEFS FOR PCDDS, PCDFS, AND DIOXIN-LIKE PCBS

    EPA Science Inventory

    The toxic equivalency factor (TEF) approach has been widely accepted as the most feasible and plausible method presently available for evaluating potential health risks associated with exposure to mixtures of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofuran...

  18. National Dioxin Air Monitoring Network (Ndamn) Report of the Results of Atmospheric Measurements of Pcdds, Pcdfs, and Dioxin-Like PCBs in Rural and Remote Areas of the U.S. from June 1998 Through November 2004

    EPA Science Inventory

    Cover of the EPA Dioxin-like Compounds 2013 Final Report In 1998, the U.S. Environmental Protection Agency (U.S. EPA) established the Nation...

  19. Fuentes de variabilidad en el diagnóstico de gastritis atrófica multifocal asociada con la infección por Helicobacter pylori1

    PubMed Central

    Bravo, Luis Eduardo; Bravo, Juan Carlos; Realpe, José Luis; Zarama, Guillermo; Piazuelo, MarÍa Blanca; Correa, Pelayo

    2014-01-01

    RESUMEN Introducción El mapeo de las diferentes regiones del estómago y el número de fragmentos de mucosa gástrica disponibles para evaluación histopatológica son fuentes importantes de variación en el momento de clasificar y hacer la gradación de la gastritis crónica. Objetivos Estimar la sensibilidad del número de fragmentos de mucosa gástrica necesarios para establecer los diagnósticos de gastritis atrófica con metaplasia intestinal (MI), displasia y estado de infección por Helicobacter pylori. Además evaluar la variabilidad intra-observador en la clasificación de estas lesiones precursoras del cáncer gástrico. Materiales y métodos En una cohorte de 6 años de seguimiento se evaluaron 1,958 procedimientos de endoscopia realizados por dos gastroenterólogos. En cada procedimiento y de cada participante se obtuvieron 5 biopsias de mucosa gástrica que representaban antro, incisura angularis y cuerpo. Un único patólogo hizo la interpretación histológica de las 5 biopsias y proporcionó un diagnóstico definitivo global que se utilizó como patrón de referencia. Cada fragmento de mucosa gástrica examinado condujo a un diagnóstico individual para cada biopsia que se comparó con el patrón de referencia. La variabilidad intra-observador se evaluó en 127 personas que corresponden a una muestra aleatoria de 20% del total de endoscopias hechas a los 72 meses de seguimiento. Resultados La sensibilidad del diagnóstico de MI y displasia gástrica aumentó de manera significativa con el número de fragmentos de mucosa gástrica evaluados El sitio anatómico de mayor sensibilidad para el diagnóstico de MI y displasia fue la incisura angularis. Para descubrir H. pylori se logró alta sensibilidad con el estudio de un solo fragmento de mucosa gástrica (95.9%) y fue independiente del sitio de obtención de la biopsia. El acuerdo intra-observador para el diagnóstico de gastritis crónica fue 86.1% con valor kappa de 0.79 IC 95% (0.76-0.85). Las

  20. A UV-vis study of the effects of alcohols on formation and stability of Mn(por)(O)(OAc) complexes

    NASA Astrophysics Data System (ADS)

    Mohajer, Daryoush; Jahanbani, Maryam

    2012-06-01

    Interactions of three different (acetato) (tetraarylporphyrinato) manganese (III) MnIII(por) with tetra-n-butylammonium hydrogen monopersulfate (n-Bu4NHSO5), in the presence of excess tetra-n-butylammonium acetate (n-Bu4NOAc) and in the absence or presence of various alcohols (alcohols = CH3OH, C2H5OH, i-C3H7OH, t-C4H9OH) in CH2Cl2, were monitored by their UV-vis spectral changes, under identical conditions, at room temperature. (Acetato) (tetrakispentafluorophenylporphyrinato) manganese (III) MnIII(tpfpp)(OAc) and (acetato) (tetramesitylporphyrinato) manganese (III) MnIII(tmp)(OAc) produced their corresponding high valent Mn(tpfpp)(O)(OAc) and Mn(tmp)(O)(OAc) both in the absence or presence of alcohols. Whereas, (acetato) (tetraphenylporphyrinato) manganese (III) MnIII(tpp)(OAc) only generated Mn(tpp)(O)(OAc) in the presence of less bulky alcohols. In the absence of alcohols or in the presence of t-C4H9OH, the UV-vis spectra displayed a very weak sign of formation of Mn(tpp)(O)(OAc) complex. It was observed that alcohols generally increased the rate of formation of Mn-oxo species in accordance with their acidity or hydrogen bonding strength, and enhanced the stability of Mn-oxo complexes, as their size increases. Attempts are made to explain these effects. A mechanistic scheme is also suggested for the decomposition of HSO5- to O2 and HSO4-, through the formation and dimerization of Mn-oxo species.

  1. Estudio teórico de la desorción de Na y K de SiO2 estimulada por la acción de fotones o electrones

    NASA Astrophysics Data System (ADS)

    Domínguez Ariza, D.; López, N.; Illas, F.; Pacchioni, G.; Madey, T. E.

    Se ha estudiado el mecanismo de generación de sodio y potasio atómico a partir de muestras de SiO2 utilizando cálculos basados tanto en la teoría del funcional de la densidad como en métodos post-Hartree Fock, así como en el método de cluster para modelar el sólido. Como consecuencia del estudio se han propuesto distintos caminos posibles para la desorción, estimulada por la acción de fotones o electrones, de sodio y potasio desde el óxido de silicio, proporcionando por lo tanto una explicación a la atmósfera tenue de sodio y potasio de La Luna.

  2. La inserción en el mercado laboral de los inmigrantes latinos en España y en los Estados Unidos: Diferencias por país de origen y estatus legal

    PubMed Central

    Connor, Phillip; Massey, Douglas

    2013-01-01

    Resumen Este artículo compara los resultados económicos entre los inmigrantes latinoamericanos en España y Estados Unidos. Detectamos un efecto de selección por el que la mayoría de los inmigrantes latinoamericanos en España proceden de Sudamérica de un entorno de clases medias, mientras la mayoría de los inmigrantes que van a los Estados Unidos son centroamericanos de clase baja. Este efecto de selección explica las diferencias transnacionales en la probabilidad de empleo, logro ocupacional y salarios obtenidos. A pesar de las diferencias en los orígenes y las características de los latinoamericanos en ambos países, los factores demográficos, humanos y de capital social parecen operar de forma similar en ambos países; y cuando los modelos se estiman separadamente por estatus legal, descubrimos que los efectos se acentúan más entre los inmigrantes irregulares cuando se los compara con los regulares, especialmente en Estados Unidos. PMID:24532857

  3. Aquisição fonológica do português brasileiro por crianças ouvintes bilíngues bimodais e surdas usuárias de implante coclear

    PubMed Central

    Cruz, Carina Rebello; Finger, Ingrid

    2014-01-01

    Resumo O presente estudo investiga a aquisição fonológica do Português Brasileiro (PB) por 24 crianças ouvintes bilíngues bimodais, com acesso irrestrito à Língua Brasileira de Sinais (Libras), e por 6 crianças surdas que utilizam implante coclear (IC), com acesso restrito ou irrestrito à Libras. Para a avaliação do sistema fonológico das crianças em PB, foi utilizada a Parte A, Prova de Nomeação, do ABFW – Teste de Linguagem Infantil (ANDRADE et al. 2004). Os resultados revelaram que as crianças ouvintes bilíngues bimodais e a criança surda usuária de IC com acesso irrestrito à Libras apresentaram processo de aquisição fonológica esperada (normal) para a sua faixa etária. Considera-se que a aquisição precoce e o acesso irrestrito à Libras podem ter sido determinantes para o desempenho dessas crianças no teste oral utilizado. PMID:25506105

  4. The Understanding of Astronomy Concepts by Students from Basic Education of a Public School. (Spanish Title: El Entendimiento de Conceptos de Aastronmía Por Los Alumnos de Educación Básica en Una Escuela Pública.) O Entendimento de Conceitos de Astronomia Por Alunos da Educação Básica: O Caso de Uma Escola Pública Brasileira

    NASA Astrophysics Data System (ADS)

    Iria Machado, Daniel; dos Santos, Carlos

    2011-07-01

    We present the results obtained in a research on the comprehension of basic astronomical concepts, in which 561 students from fifth grade middle school to third grade high school of a public school of the city of Foz do Iguaçu (Brazil) took part. A test with 20 multiple-choice questions was applied to indentify the most common conceptions expressed by the students. This test was elaborated based on the literature about misconceptions and covered the following topics: the day-night cycle; the time zones; the seasons of the year; the phases of the Moon; the movement of the Moon; the apparent movement of the Sun in the celestial sphere; the eclipses; the dimensions and distances in the Universe; the brightness of the stars and its observation from Earth. Though a small progress was verified in the proportion of scientifically acceptable answers when comparing the eighth grade of middle school to the fifth, and the third grade of high school to the first, there was an overall predominance of alternative conceptions regarding most of the explored subjects, which persisted up to the last year of secondary school. The comparison to data found in this research made in other socio-cultural contexts revealed, in many aspects, similar notions and difficulties revealed by the students. Se presentan los resultados de una investigación sobre la comprensión de conceptos astronómicos básicos, en la cual participaron 561 estudiantes que cursaban entre el quinto grado de la enseñanza primaria y el tercer año de la enseñanza secundaria de una escuela pública de la ciudad de Foz do Iguaçu (Brasil). Se utilizó un test de 20 preguntas de opción múltiple para identificar las concepciones más comunes expresadas por los estudiantes. Este instrumento de recolección de datos se desarrolló en base a la literatura sobre las concepciones alternativas y trató los siguientes temas: el ciclo día-noche, los husos horarios, las estaciones del año, las fases de la Luna, el

  5. The Understanding of Astronomy Concepts by Students from Basic Education of a Public School. (Spanish Title: El Entendimiento de Conceptos de Aastronmía Por Los Alumnos de Educación Básica en Una Escuela Pública.) O Entendimento de Conceitos de Astronomia Por Alunos da Educação Básica: O Caso de Uma Escola Pública Brasileira

    NASA Astrophysics Data System (ADS)

    Iria Machado, Daniel; dos Santos, Carlos

    2011-07-01

    We present the results obtained in a research on the comprehension of basic astronomical concepts, in which 561 students from fifth grade middle school to third grade high school of a public school of the city of Foz do Iguaçu (Brazil) took part. A test with 20 multiple-choice questions was applied to indentify the most common conceptions expressed by the students. This test was elaborated based on the literature about misconceptions and covered the following topics: the day-night cycle; the time zones; the seasons of the year; the phases of the Moon; the movement of the Moon; the apparent movement of the Sun in the celestial sphere; the eclipses; the dimensions and distances in the Universe; the brightness of the stars and its observation from Earth. Though a small progress was verified in the proportion of scientifically acceptable answers when comparing the eighth grade of middle school to the fifth, and the third grade of high school to the first, there was an overall predominance of alternative conceptions regarding most of the explored subjects, which persisted up to the last year of secondary school. The comparison to data found in this research made in other socio-cultural contexts revealed, in many aspects, similar notions and difficulties revealed by the students. Se presentan los resultados de una investigación sobre la comprensión de conceptos astronómicos básicos, en la cual participaron 561 estudiantes que cursaban entre el quinto grado de la enseñanza primaria y el tercer año de la enseñanza secundaria de una escuela pública de la ciudad de Foz do Iguaçu (Brasil). Se utilizó un test de 20 preguntas de opción múltiple para identificar las concepciones más comunes expresadas por los estudiantes. Este instrumento de recolección de datos se desarrolló en base a la literatura sobre las concepciones alternativas y trató los siguientes temas: el ciclo día-noche, los husos horarios, las estaciones del año, las fases de la Luna, el

  6. Polychlorinated dibenzofurans and dibenzo-p-dioxins and other chlorinated contaminants in cow milk from various locations in Switzerland

    SciTech Connect

    Rappe, C.; Nygren, M.; Lindstroem, G.; Buser, H.R.; Blaser, O.; Wuethrich, C.

    1987-10-01

    Six samples of cow milk from various locations in Switzerland were analyzed for polychlorinated dibenzo-furans (PCDFs), polychlorinated dibenzo-p-dioxins (PCDDs), and other chlorinated contaminants. Sub parts per trillion levels of 2,3,7,8-substituted PCDFs and PCDDs were found in all samples. The levels were higher in samples collected in the vicinity of incinerators. Non-2,3,7,8-substituted PCDDs and PCDFs were not found in the milk samples.

  7. Characterization of fHbp, nhba (gna2132), nadA, porA, Sequence Type (ST), and Genomic Presence of IS1301 in Group B Meningococcal ST269 Clonal Complex Isolates from England and Wales▿

    PubMed Central

    Lucidarme, Jay; Comanducci, Maurizio; Findlow, Jamie; Gray, Stephen J.; Kaczmarski, Edward B.; Guiver, Malcolm; Kugelberg, Elisabeth; Vallely, Pamela J.; Oster, Philipp; Pizza, Mariagrazia; Bambini, Stefania; Muzzi, Alessandro; Tang, Christoph M.; Borrow, Ray

    2009-01-01

    Highly effective glycoconjugate vaccines exist against four of the five major pathogenic groups of meningococci: A, C, W-135, and Y. An equivalent vaccine against group B meningococci (menB) has remained elusive due to the poorly immunogenic capsular polysaccharide. A promising alternative, the investigational recombinant menB (rMenB)- outer membrane vesicle (OMV) vaccine, contains fHBP, NHBA (previously GNA2132), NadA, and outer membrane vesicles (OMVs) from the New Zealand MeNZB vaccine. MenB currently accounts for 90% of meningococcal disease in England and Wales, where the multilocus sequence type (ST) 269 (ST269) clonal complex (cc269) has recently expanded to account for a third of menB cases. To assess the potential cc269 coverage of the rMenB-OMV vaccine, English and Welsh cc269 isolates from the past decade were genetically characterized with respect to fHBP, NHBA, and NadA. All of the isolates harbored fHbp and nhba alleles, while 98% of the cc269 isolates were devoid of nadA. Subvariant profiling of fHbp, nhba, and porA against STs revealed the presence of two broadly distinct and well-defined clusters of isolates, centered around ST269 and ST275, respectively. An additional molecular marker, insertion sequence IS1301, was found to be present in 100% and <2% of isolates of the respective clusters. On the basis of the genetic data, the potential rMenB-OMV coverage of cc269 in England and Wales is high (up to 100%) within both clusters. Expression studies and serum bactericidal antibody assays will serve to enhance predictions of coverage and will augment ongoing studies regarding the significance of IS1301 within the ST269 cluster. PMID:19759227

  8. Characterization of invasive Neisseria meningitidis from Atlantic Canada, 2009 to 2013: With special reference to the nonpolysaccharide vaccine targets (PorA, factor H binding protein, Neisseria heparin-binding antigen and Neisseria adhesin A)

    PubMed Central

    Tsang, Raymond SW; Law, Dennis KS; Gad, Rita R; Mailman, Tim; German, Gregory; Needle, Robert

    2015-01-01

    BACKGROUND: Serogroup B Neisseria meningitidis (MenB) has always been a major cause of invasive meningococcal disease (IMD) in Canada. With the successful implementation of a meningitis C conjugate vaccine, the majority of IMD in Canada is now caused by MenB. OBJECTIVE: To investigate IMD case isolates in Atlantic Canada from 2009 to 2013. Data were analyzed to determine the potential coverage of the newly licensed MenB vaccine. METHODS: Serogroup, serotype and serosubtype antigens were determined from IMD case isolates. Clonal analysis was performed using multilocus sequence typing. The protein-based vaccine antigen genes were sequenced and the predicted peptides were investigated. RESULTS: The majority of the IMD isolates were MenB (82.5%, 33 of 40) and, in particular, sequence type (ST)-154 B:4:P1.4 was responsible for 47.5% (19 of 40) of all IMD case isolates in Atlantic Canada. Isolates of this clone expressed the PorA antigen P1.4 and possessed the nhba genes encoding for Neisseria heparin-binding antigen peptide 2, which together matched exactly with two of the four components of the new four-component meningococcal B vaccine. Nineteen MenB isolates had two antigenic matches, another five MenB and one meningitis Y isolate had one antigenic match. This provided 75.8% (25 of 33) potential coverage for MenB, or a 62.5% (25 of 40) overall potential coverage for IMD. CONCLUSION: From 2009 to 2013, IMD in Atlantic Canada was mainly caused by MenB and, in particular, the B:4:P1.4 ST-154 clone, which accounted for 47.5% of all IMD case isolates. The new four-component meningococcal B vaccine appeared to offer adequate coverage against MenB in Atlantic Canada. PMID:26744586

  9. Characterization of fHbp, nhba (gna2132), nadA, porA, and Sequence Type in Group B Meningococcal Case Isolates Collected in England and Wales during January 2008 and Potential Coverage of an Investigational Group B Meningococcal Vaccine▿

    PubMed Central

    Lucidarme, Jay; Comanducci, Maurizio; Findlow, Jamie; Gray, Stephen J.; Kaczmarski, Edward B.; Guiver, Malcolm; Vallely, Pamela J.; Oster, Philipp; Pizza, Mariagrazia; Bambini, Stefania; Muzzi, Alessandro; Borrow, Ray

    2010-01-01

    Invasive disease caused by meningococcal capsular groups A, C, W-135, and Y is now preventable by means of glycoconjugate vaccines that target their respective polysaccharide capsules. The capsule of group B meningococci (MenB) is poorly immunogenic and may induce autoimmunity. Vaccines based on the major immunodominant surface porin, PorA, are effective against clonal epidemics but, thus far, have a limited scope of coverage against the wider MenB population at large. In an alternative approach, the first-generation, investigational, recombinant MenB (rMenB) plus outer membrane vesicle (OMV) (rMenB-OMV) vaccine contains a number of relatively conserved surface proteins, fHBP, NHBA (previously GNA2132), and NadA, alongside PorA P1.4-containing OMVs from the New Zealand MeNZB vaccine. MenB currently accounts for approximately 90% of cases of meningococcal disease in England and Wales. To assess potential rMenB-OMV vaccine coverage of pathogenic MenB isolates within this region, all English and Welsh MenB case isolates from January 2008 (n = 87) were genetically characterized with respect to fHBP, NHBA, NadA, and PorA. Alleles for fHbp, nhba, and porA were identified in all of the isolates, of which 22% were also found to harbor nadA alleles. On the basis of genotypic data and predicted immunological cross-reactivity, the potential level of rMenB-OMV vaccine coverage in England and Wales ranges from 66% to 100%. PMID:20375242

  10. NATIONAL STUDY OF CHEMICAL RESIDUES IN FISH - III. STUDY RESULTS

    EPA Science Inventory

    Bottom feeding and game fish, from each of nearly 400 sites throughout the United States were analyzed for 15 PCDD/PCDFS, PCBS, 21 pesticides and herbicides, and 13 other organic chemicals. and mercury. even of the PCDD/PCDFs and 15 of the other chemicals were detected at over 50...

  11. Neisseria gonorrhoeae antimicrobial susceptibility in Barcelona: penA, ponA, mtrR, and porB mutations and NG-MAST sequence types associated with decreased susceptibility to cephalosporins.

    PubMed

    Serra-Pladevall, J; Barberá, M J; Rodriguez, S; Bartolomé-Comas, R; Roig, G; Juvé, R; Andreu, A

    2016-09-01

    The aims of this study were to determine the antimicrobial susceptibility of Neisseria gonorrhoeae (NG) in our area, to analyze the molecular mechanisms involved in cephalosporins resistance, and to undertake molecular typing of our NG strains. Antimicrobial susceptibility was determined using the Etest. The genes penA, mtrR, penB, and ponA were studied. Molecular typing was performed by N. gonorrhoeae multiantigen sequence typing. Of 329 strains analyzed in 2013, none showed high-level cephalosporin resistance, but 8.2 % had resistance to cefixime [minimum inhibitory concentration (MIC) > 0.125 μg/mL] and 0.6 % to ceftriaxone (MIC > 0.125 μg/mL). Azithromycin resistance was documented in 4.3 % and ciprofloxacin resistance in 49.2 %. Among 48 strains with an MIC ≥ 0.125 μg/mL to cefixime, 58.3 % showed the penA mosaic pattern XXXIV, 98 % a Leu → Pro substitution at position 421 of the ponA gene, 100 % amino acid changes at positions 101 and 102 of the PorB1b porin, and 87.5 % of strains an adenine deletion in the promoter region of the MtrC-D-E efflux pump. A significant difference between strains with and without decreased cephalosporin susceptibility (MIC ≥ 0.125 μg/mL) was observed for these four genes. Of the 48 strains with an MIC ≥ 0.125 μg/mL to cefixime, 43.8 % belonged to the genogroup G1407 and 27.1 % belonged to the genogroup G2400. A significant association of G1407 with decreased susceptibility (MIC ≥ 0.125 μg/mL) and G2992 with susceptibility was found, and also between G1407 and mosaic pattern XXXIV and between G2400 and A501T substitution in penA. The NG resistance rate in our area is higher than the median of Europe. We have detected the emergence of G2400, which may be a source of antimicrobial resistance. PMID:27255221

  12. Eficacia de la detección sistemática de la gripe en las fronteras en los viajeros que llegan por vía aérea*

    PubMed Central

    Priest, Patricia C.; Jennings, Lance C.; Duncan, Alasdair R.; Brunton, Cheryl R.; Baker, Michael G.

    2015-01-01

    Objetivos. Se midieron los síntomas y la prevalencia de la gripe (también llamada influenza), así como la eficacia del mecanismo de detección sistemática basado en los síntomas y la temperatura para diagnosticar la gripe en viajeros internacionales que llegaban por vía aérea. Métodos. El presente estudio transversal recopiló datos de viajeros que llegaron al aeropuerto internacional de Christchurch (Nueva Zelandia) en el invierno del 2008 mediante un cuestionario de salud, medición de la temperatura y toma de muestras de las vías respiratorias. Resultados. De los viajeros, 15 976 (68%) entregaron los formularios completos. De ellos, 17% notificaron al menos un síntoma de gripe; los síntomas más comunes fueron rinorrea o congestión nasal (10%) y tos (8%). Se tomaron muestras de las vías respiratorias de 3 769 viajeros. La prevalencia estimada de la gripe fue de 1,1% (4% en las personas sintomáticas, 0,2% en las asintomáticas). La sensibilidad de los criterios de detección varió de 84% para “cualquier síntoma” a 3% para la fiebre de 37,8 °C o mayor. El valor predictivo positivo fue bajo para todos los criterios. Conclusiones. El método de detección sistemática en las fronteras mediante la autonotificación de síntomas y la toma de la temperatura presenta limitaciones para impedir que una gripe pandémica entre en un país. Basarse en criterios como “cualquier síntoma” o la tos haría que se investigara a varias personas no infectadas, mientras que algunas personas infectadas pasarían inadvertidas. Si se usaran criterios más específicos como la fiebre, la mayoría de las personas infectadas entrarían en el país a pesar del mecanismo de detección.

  13. New halide-centered discrete Ag(I)(8) cubic clusters containing diselenophosphate ligands, [Ag(8)(X)[Se(2)P(OR)(2)](6)](PF(6)) (X = Cl, Br; R = Et, Pr, (i)Pr): syntheses, structures, and DFT calculations.

    PubMed

    Liu, C W; Haia, Hsien-Chung; Hung, Chiu-Mine; Santra, Bidyut Kumar; Liaw, Ben-Jie; Lin, Zhenyang; Wang, Ju-Chun

    2004-07-12

    Six clusters Ag(8)(micro(8)-X)[Se(2)P(OR)(2)](6)(PF(6)) (R = Et, X = Cl, 1a, X = Br, 1b; R = Pr, X = Cl, 2a, X = Br, 2b; R = (i)Pr, X = Cl, 3a, X = Br, 3b) were isolated from the reaction of [Ag(CH(3)CN)(4)](PF(6)), NH(4)[Se(2)P(OR)(2)], and Bu(4)NX in a molar ratio of 4:3:1 in CH(2)X(2). Positive FAB mass spectra show m/z peaks at 2573.2 for 1a, 2617.3 for 1b, 2740.9 for 2a, 2786.9 for 2b, 2742.3 for 3a, and 2787.0 for 3b due to respective molecular cation, (M - PF(6))(+). (31)P NMR spectra of 1a-3b display a singlet at delta 82.3, 81.5, 82.9, 81.7, 76.3, and 75.8 ppm with a set of satellites (J(PSe) = 661, 664, 652, 652, 656, and 656 Hz, respectively). The X-ray structure (1a-2b) consists of a discrete cationic cluster in which eight silver ions are linked by six diselenophosphate ligands and a central micro(8)-Cl or micro(8)-Br ion with a noncoordinating PF(6)(-) anion. The shape of the molecule is a halide-centered distorted Ag(8) cubic cluster. The dsep ligand exhibits a tetrametallic tetraconnective (micro(2), micro(2)) coordination pattern, and each caps on a square face of the cube. Each silver atom of the cube is coordinated by three selenium atoms and the central chloride or bromide ion. Additionally, molecular orbital calculations at the B3LYP level of the density functional theory have been carried out to study the Ag-micro(8)-X (X = Cl, Br) interactions for cluster cations [Ag(8)(micro(8)-X)[Se(2)P(OR)(2)](6)](+). Calculations show very weak bonding interactions exist between micro(8)-X and Ag atoms of the cube. PMID:15236560

  14. Origin attribution of polychlorinated dibenzo-p-dioxins and dibenzofurans in sediment and soil from a Japanese freshwater lake area through congener-specific data analysis.

    PubMed

    Sakurai, T; Suzuki, N; Masunaga, S; Nakanishi, J

    1998-01-01

    Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs) in sediment and soil from a freshwater lake area were congener-specifically determined. The obtained data were examined to estimate the major origins of these compounds, with the aid of principal component analysis (PCA). Four major principal components (PCs) were obtained, and three of them were attributed to PCDDs/PCDFs in the atmosphere, in a diphenyl ether herbicide and in pentachlorophenol, based on congener-specific comparisons with references. One PC remained unattributed. These four were interpreted as the major origins of PCDDs/PCDFs in the area. The relative influence of the origins was also investigated. PMID:9828338

  15. Novel chloride-centered discrete CuI8 cubic clusters containing diselenophosphate ligands. Syntheses and structures of [Cu8(mu8-Cl)[Se2P(OR)2](6)](PF6) (R = Et, Pr, iPr)1.

    PubMed

    Liu, C W; Hung, Chiu-Mine; Santra, Bidyut Kumar; Chen, Hsiu-Chih; Hsueh, Hsin-Hsueh; Wang, Ju-Chung

    2003-05-19

    Three clusters 1-3, Cu(8)(mu8-Cl)[Se(2)P(OR)(2)](6)(PF(6)) (R= Et, Pr, (i)Pr), were synthesized in high yield from the reaction of [Cu(CH(3)CN)(4)](PF(6)), NH(4)[Se(2)P(OR)(2)], and Bu(4)NCl in a molar ratio of 4:3:1 in diethyl ether. FAB mass spectra show m/z peaks at 2218.10 for 1, 2386.10 for 2, and 2387.34 for 3 which are due to molecular cations, [1-PF(6)]+, [2-PF(6)]+, and [3-PF(6)]+, respectively. (31)P NMR spectra of 1-3 display a singlet at delta 76.48, 76.73, and 69.32 ppm with satellites (J(PSe) = 652, 653, and 648 Hz), respectively. The (77)Se NMR spectra of 1-3 exhibit a doublet peak at -21.7, -16.42, and 2.3 ppm, respectively (J(SeP) = 652 Hz for 1, 653 Hz for 2, and 648 Hz for 3). The X-ray structure (1-3) consists of a discrete cationic cluster in which eight copper ions are linked by six diselenophosphate ligands and a central mu8-Cl ion with a noncoordinating PF(6)(-) anion. The shape of the molecule is a chloride-centered distorted Cu(8) cube in clusters 1 and 2 and a near perfect Cu(8) cube for cluster 3. The dsep ligand exhibits a tetrametallic tetraconnective (mu2, mu2)) coordination pattern, and each occupies a square face of the cube. Each copper atom of the cube is coordinated by three selenium atoms with a strong interaction with the central chloride ion. The observed Cu-Cl distances lie in the range 2.649-2.878 A. PMID:12739962

  16. POLYCHLORINATED BIPHENYL AND POLYCHLORINATED DIBENZOFURAN BIOMARKERS OF RISK ASSESSMENT IN ADOLESCENT CHILDREN AND THEIR MOTHERS

    EPA Science Inventory

    This is two cohort comparison study of endocrine and cytochrome P450 family 1 biomarkers for risk assessment of polychlorinalted biphenyls (PCBs)/polychlorinated dibenzofurans (PCDFs) induced developmental toxicities in the human. The subjects will be sexually mature adoles...

  17. PCDD and PCDF Emissions from Simulated Sugarcane Field Burning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The emissions from simulated sugarcane (Saccharum officinarum) field burns were sampled and analyzed for polychlorinated dibenzodioxins and dibenzofurans (PCDDs and PCDFs). Sugarcane leaves from Hawaii and Florida were burned in a manner simulating the natural physical dimensions and biomass densit...

  18. Degradation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans by the white rot fungus Phanerochaete sordida YK-624.

    PubMed Central

    Takada, S; Nakamura, M; Matsueda, T; Kondo, R; Sakai, K

    1996-01-01

    A method for the degradation of dioxins by white rot fungi was developed. Degradation of a mixture of 10 kinds of tetra- to octachlorodibenzo-p-dioxins (polychlorinated dibenzo-p-dioxins [PCDDs]) and tetra- to octachlorodibenzofurans (polychlorinated dibenzofurans [PCDFs]), which were chlorinated at 2-, 3-, 7-, and 8-positions of the molecules, by the white rot fungus Phanerochaete sordida YK-624 was studied in a stationary low-nitrogen medium. The percent degradation values of PCDDs and PCDFs were approximately 40 (tetra-chloro-) to 76% (hexachloro-) and 45 (tetrachloro-) to 70% (hexachloro-), respectively. Metabolites of 2,3,7,8-tetra- and octaCDD formed by P. sordida YK-624 included 4,5-dichlorocatechol and tetrachlorocatechol, respectively. These results suggest that white rot fungus is able to substantially degrade both PCDDs and PCDFs. This is the first report of the degradation of highly chlorinated PCDDs and PCDFs by a microorganism. PMID:8953705

  19. PCDD AND PCDF EMISSIONS FROM SIMULATED SUGARCANE FIELD BURNING

    EPA Science Inventory

    The emissions from simulated sugarcane field burns were sampled and analyzed for polychlorinated dibenzodioxins and dibenzofurans (PCDDs and PCDFs). Sugarcane leaves from Hawaii and Florida were burned in a manner simulating the natural physical dimensions and biomass density fou...

  20. GEOCHEMICAL STUDY OF SEDIMENT CONTAMINATION IN NEW BEDFORD HARBOR, MASSACHUSETTS

    EPA Science Inventory

    Chemical analyses of sediment samples collected along a transect in New Bedford harbor revealed a gradient of increasing concentrations of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polycyclic aromatic hydro...

  1. Framework for Application of the Toxicity Equivalence Methodology for Polychlorinated Dioxins, Furans and Biphenyls in Ecological Risk Assessment (External Review Draft)

    EPA Science Inventory

    Polychlorinated dioxins (PCDDs), furans (PCDFs), and biphenyls (PCBs) are persistent contaminants found widely in the environment. Several of these compounds bioaccumulate in the tissues of fish, birds, and mammals, where they have been demonstrated to cause mortality and adverse...

  2. AN ALTERNATIVE METHOD FOR ESTABLISHING TEFS FOR DIOXIN-LIKE COMPOUNDS. PART 1. EVALUATION OF DECISION ANALYSIS METHODS FOR USE IN WEIGHTING RELATIVE POTENCY DATA

    EPA Science Inventory

    A number of investigators have recently examined the utility of applying probabilistic techniques in the derivation of toxic equivalency factors (TEFs) for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (...

  3. IMMUNOCHEMICAL DETERMINATION OF DIOXINS IN SEDIMENT SAMPLES

    EPA Science Inventory

    Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are considered highly toxic contaminants with the environmental monitoring of these compounds being of great importance. Immunoassay procedures such as the enzyme-linked immunosorbent assay (ELIS...

  4. IMMUNOCHEMICAL DETERMINATION OF DIOXINS IN SEDIMENT AND SERUM SAMPLES

    EPA Science Inventory

    Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are considered highly toxic contaminants and the environmental and biological monitoring of these compounds is of great concern. Immunoassays may be used as screening methods to satisfy the gro...

  5. ROLE OF SULFUR IN REDUCING PCDD AND PCDF FORMATION

    EPA Science Inventory

    Past research has suggested that the presence of sulfur (S) in municipal waste combustors (MWCs) can decrease downstream formation of chlorinated organic compounds, particularly polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Thus, co-firing a...

  6. FUNCTIONAL ASPECTS OF DEVELOPMENTAL TOXICITY OF POLYHALOGENATED AROMATIC HYDROCARBONS IN EXPERIMENTAL ANIMALS AND HUMAN INFANTS

    EPA Science Inventory

    A scientific evaluation was made of functional aspects of developmental toxicity of polychlorinated biphenyls (PCBs)-dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in experimental animals and in human infants. ersistent neurobehavioral, reproductive, and endocrine alteration...

  7. AN ALTERNATIVE METHOD FOR ESTABLISHING TEFS FOR DIXON-LIKE COMPOUNDS. PART 2. DEVELOPMENT OF AN APPROACH TO QUANTITATIVELY WEIGHT THE UNDERLYING POTENCY DATA

    EPA Science Inventory

    The current approach for evaluating potential health risks associated with exposure to mixtures of polychlorinated dibenzo-p-dixoins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (PCBs) [hereafter referred to as "dioxin-like compoun...

  8. FRAMEWORK FOR THE APPLICATION OF THE TOXICITY EQUIVALENCE METHODOLOGY FOR POLYCHLORINATED DIOXINS, FURANS, AND PCBS IN ECOLOGICAL RISK ASSESSMENT.

    EPA Science Inventory

    Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) are persistent contaminants found widely in the environment. Several of these compounds bioaccumulate in the tissues of fish, birds, and mammals, and have been demonstrated to cause mortality a...

  9. A PERFORMANCE HISTORY OF THE BASE CATALYZED DECOMPOSITION (BCD) PROCESS

    EPA Science Inventory

    Remediation of halogenated organic compounds--such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs)--poses a challenge because these compounds are resistant to microbial attack and to degradation by many com...

  10. EMISSIONS OF METALS, CHROMIUM AND NICKEL SPECIES, AND ORGANICS FROM MUNICIPAL WASTEWATER SLUDGE INCINERATORS

    EPA Science Inventory

    In order to provide data to support regulations on municipal wastewater sludge incineration, emissions of metals, hexavalent chromium, nickel subsulfide, polychlorinated dibenzo-dioxins and furans (PCDD/PCDFs), semivolatile and volatile organic compounds, carbon monoxide (CO)...

  11. La busqueda textual por computadora (Textual Search by Computer)

    ERIC Educational Resources Information Center

    Davison, Ned J.

    1977-01-01

    Describes the use of the computer program EDIT for textual searches to locate a certain programmed word or word root. In the examples explained here, the vocabulary search is performed on poetry and allows examination of the metaphorical and conceptual poetic atmosphere achieved through word use. (Text is in Spanish.) (CHK)

  12. On the Use of "Por" Plus Agent with "Se" Construction

    ERIC Educational Resources Information Center

    De Mello, George

    1978-01-01

    Two explanations for the role of "se" in such constructions as "Se construyen casas" are given by grammarians; one states that it is a passive interpretation ("Houses are built"), the other advocates an impersonal interpretation ("One builds houses"). Different views are presented and analyzed. (Author/NCR)

  13. Por los Ninos (For the Children): Education of Undocumented Children.

    ERIC Educational Resources Information Center

    Gonzalez, Elena R.; Team, Linda B.

    Published as a special project of Texas IMPACT and the Texas Conference of Churches, this booklet outlines legal aspects of the education of undocumented children, lists moral and practical reasons for educating them, provides reasons for changing the Texas law which prohibits use of state funds for education of children who are not legally…

  14. POR FIN (Program Organizing Related Family Instruction in the Neighborhood).

    ERIC Educational Resources Information Center

    1971

    A project was undertaken in San Antonio, Texas, to develop a recruitment approach which would be more effective than the traditional mass media approach in recruiting hard-core undereducated individuals into adult education classes. An experiment was designed to test a recruiting method which would employ a personal, face-to-face interview…

  15. [The right to avoid pregnancy] [POR, ENG translation included].

    PubMed

    1981-01-21

    Signs are finally appearing in Brazil that despite the government's hesitations and the hostility of the Catholic Church the decade of the 1980s shall bring effective changes intended to restrain population growth. Now, 4 years after its inclusion in the social program of the Geisel administration in 1977, family planning will become a reality. It is certainly about time, for at the present rate of growth the Brazilian population increases by about 6 persons per minute--about 3 million a year. At this pace, only a large scale State intervention that provides the population with information, assistance and free access to contraception may decisively reverse the trend. Figueiredo's government has decided that family planning should be introduced slowly, gradually and subtly, thus avoiding specific programs and publicity campaigns through the mass communication vehicles. In an effort to get around sharper criticism from the Church and the opposition, the government intends to mobilize catholic laypersons, priests, and nuns and, if possible, bishops in a national attempt to disseminate information on natural methods of birth control. As a 1st step, the Ministry of Health will widely distribute information on human reproduction and fecundity along with explanations of artificial contraceptive methods. Subject to the couple's decision and under medical indications, the free supply of contraceptive means to low income families shall be ensured by the government. The government will also allow sterilization. Despite its cautious approach, in actuality the government's program will in many places and circumstances be a massive inducement to contraceptive use. PMID:12337558

  16. Formation of polychlorinated dibenzofurans and dioxins during combustion, electrical equipment fires and PCB incineration.

    PubMed Central

    Hutzinger, O; Choudhry, G G; Chittim, B G; Johnston, L E

    1985-01-01

    Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are likely formed by thermal synthesis of a variety of primary precursors. Highest levels of these compounds are expected, however, when the starting material requires only one or two reaction steps for their formation, as is the case with chlorophenols, chlorobenzenes and polychlorinated biphenyls (PCBs). Laboratory pyrolyses have indeed shown that PCBs give significant yields of PCDFs, and chlorobenzenes give both PCDFs and PCDDs. In addition, a variety of other chloroaromatic compounds are formed. From these experiments and from accidents involving PCB fires, it is known that PCDFs are the most important toxic compounds associated with PCBs. Most commercial PCBs contain PCDFs in the low ppm range. PCDF concentration does not increase during normal operation in electrical equipment. Accidents (fires and explosions) involving PCBs can give PCDF levels in soot of up to 1000 ppm and higher. Effective thermal destruction of PCB is possible in modern incineration units, provided high temperatures, excess air and sufficient residence times are used. Exact figures for minimum temperature and residence time cannot be given, since feedstock and incinerator construction greatly influence destruction efficiency. Effluents from EPA-licensed incinerators used for PCB destruction contain only very low levels of PCDDs and PCDFs. PMID:3928357

  17. Síndrome del Outlet Torácico: ¿Una Patología Siempre Quirúrgica? Análisis de una Serie de 31 Cirugías Realizadas por Vía Supraclavicular Serie clínica

    PubMed Central

    Socolovsky, Mariano; Di Masi, Gilda; Binaghi, Daniela; Campero, Álvaro; Páez, Miguel Domínguez; Dubrovsky, Alberto

    2014-01-01

    Introducción: El síndrome de outlet torácico es una compresión del plexo braquial que suscita polémica. Se clasifica en Outlet Torácico Verdadero o neurogénico (OTV) y Outlet Torácico Disputado o no neurogénico (OTD). El primero presenta síntomas motores en la mano, mientras que el segundo sólo síntomas sensitivos en el miembro superior. El objetivo de este trabajo es analizar los resultados obtenidos en una serie de 31 cirugías. Métodos: Se analizaron las cirugías de nervios efectuadas entre 2003-2012, tomando los diagnósticos de outlet torácico cuyo período de seguimiento post-operatorio mínimo fuera de 6 meses. Se buscaron los siguientes datos: edad, sexo, presencia de síntomas sensitivos y/o motores, clasificación, resultado de los estudios neurofisiológicos y de imágenes, resultado de la cirugía, complicaciones post-operatorias y recidivas. Resultados: Se incluyeron 31 cirugías realizadas en 30 pacientes, 9 OTV (8 mujeres) de 24.3 años, y 21 con OTD (18 mujeres) de 37.4 años de edad en promedio. Un 90% presentaron alteraciones neurofisiológicas preoperatorias, y 66,6% imagenológicas. En el intraoperatorio, el 100% de los OTV presentó una alteración anatómica relacionada con la sintomatología, hecho observado sólo en el 36.7% de los OTD operados. El 87,5% de los OTV mejoraron sensitivamente, mientras que 77,7% mejoraron la atrofia. Por el contrario, 45.4% de los OTD mejoraron permanentemente, 36.3% no tuvieron cambios, 13.6% mejoraron transitoriamente y 4.5% (un caso) empeoró. Las complicaciones post-operatorias fueron más frecuentes aunque transitorias en el grupo de OTV (3 casos sobre 9 operados, 33.3%) que en los OTD (3 casos sobre 22, un 13.6%). Conclusión: El OTV suele mayormente mejorar luego de la cirugía, igual que el OTD aunque en una proporción mucho menor. Estos hallazgos coinciden con otros reportes recientes de esta patología. PMID:25165614

  18. A Comparison Between PSRK and GERG-2004 Equation of State for Simulation of Non-Isothermal Compressible Natural Gases Mixed with Hydrogen in Pipelines / Porównanie równań stanu opracowanych według metody PSRK oraz GERG-2004 wykorzystanych do symulacji zachowania ściśliwych mieszanin gazu ziemnego i wodoru w rurociągach, w warunkach przepływów nie-izotermicznych

    NASA Astrophysics Data System (ADS)

    Uilhoorn, Frits E.

    2013-06-01

    In this work, the GERG-2004 equation of state based on a multi-fluid approximation explicit in the reduced Helmholtz energy is compared with the predictive Soave-Redlich-Kwong group contribution method. In the analysis, both equations of state are compared by simulating a non-isothermal transient flow of natural gas and mixed hydrogen-natural gas in pipelines. Besides the flow conditions also linepack-energy and energy consumption of the compressor station are computed. The gas flow is described by a set of partial differential equations resulting from the conservation of mass, momentum and energy. A pipeline section of the Yamal-Europe gas pipeline on Polish territory has been selected for the case study. W artykule dokonano porównania wyników uzyskanych przy wykorzystaniu równania stanu GERG- 2004 opartego na jawnym przybliżeniu wyników dla wielu cieczy w oparciu o zredukowaną energię Helmhotza oraz wyników uzyskanych w oparciu o metodę Soave-Redlich Kwonga. Obydwa równania stanu porównano poprzez przeprowadzenie symulacji stanów przejściowych przepływów gazu ziemnego oraz mieszanin gazu ziemnego i wodoru w rurociągach w warunkach przepływów nie-izotermicznych. Oprócz warunków przepływu, określono energię w napełnionym układzie oraz zużycie energii przez stację kompresora. Przepływ gazu opisano zbiorem równań różniczkowych cząstkowych, wyprowadzonych w oparciu o prawa zachowania masy, pędu i energii. Jako studium przypadku wybrano fragment rurociągu jamalskiego (Yamal- Europa) przebiegającego przez terytorium Polski.

  19. Key parameters for de novo formation of polychlorinated dibenzo-p-dioxins and dibenzofurans.

    PubMed

    Wikström, Evalena; Ryan, Shawn; Touati, Abderrahmane; Gullet, Brian K

    2003-05-01

    De novo formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs and PCDFs) was investigated in an Entrained Flow Reactor (EFR) to simulate combustion conditions. The parameters investigated were carbon content and nature in fly ash; type of gas-phase environment (oxidative versus reducing conditions) influence of combustion gases such as water, carbon monoxide, and carbon dioxide; amount of gas-phase chlorine; reaction temperature (250-600 degrees C); and reaction time (minutes vs hours). The comprehensive data set was further evaluated with principal component analysis (PCA) to statistically determine the role and importance of each parameter for de novo formation of PCDDs and PCDFs. Results revealed that an initial fast de novo formation occurs within the first minutes with a formation rate in the orders of hundreds of pmol per minutes; however, the reactivity of the ash was found to decline with time. An average formation rate as low as 3 pmol/min was measured after 6 h. The slower de novo formation of PCDDs and PCDFs was found to be through different reaction mechanisms and, thus, controlled by different parameters. The amount of Cl2 in the gas phase was observed to be an important parameter for PCDFs formation; meanwhile the levels of O2 were not found to be a PCDF rate controlling parameter. The formation rate of PCDDs was significantly lower than the PCDFs, and two mechanisms appear to be controlling the formation, one depending on the amount of O2 and one on the amount of Cl2 present in the gas phase. Overall the most significant parameter for the rate of formation for both PCDDs and PCDFs was revealed to be the reaction temperature. A maximum rate of formation was observed between 300-400 degrees C for the PCDDs and 400-500 degrees C for the PCDFs. PMID:12775072

  20. Thermal desorption of PCBs from contaminated soil with copper dichloride.

    PubMed

    Liu, Jie; Qi, Zhifu; Li, Xiaodong; Chen, Tong; Buekens, Alfons; Yan, Jianhua; Ni, Mingjiang

    2015-12-01

    Copper dichloride is an important catalyst both in the dechlorination of chlorinated aromatic compounds and the formation of PCDD/Fs. The effect of copper dichloride on polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) was studied in treated soil and off gas after thermal desorption of PCB-contaminated soil at 300, 400, 500, 600 °C. The presence of copper dichloride clearly enhances thermal desorption by promoting PCBs removal, destruction, and dechlorination. After thermal treatment at 600 °C for 1 h, the removal efficiency and destruction efficiency for PCBs reached 98.1 and 93.9%, respectively. Compared with the positive influence on PCBs, copper dichloride catalyzed large amount of PCDFs formation at 300 °C, with the concentration ratio of 2.35. The effect of CuCl2 on PCDFs formation weakened with the rising temperature since PCDFs destruction became dominant under higher temperature. Different from PCDFs, PCDDs concentration in treated soil and off gas decreased continuously with the increasing temperature. PMID:26233752

  1. Polychlorinated dibenzo- p-dioxins, dibenzofurans, and biphenyls in soils of Moscow

    NASA Astrophysics Data System (ADS)

    Shelepchikov, A. A.; Brodskii, E. S.; Feshin, D. B.; Zhil'Nikov, V. G.; Mir-Kadyrova, E. Ya.; Balashova, S. P.

    2011-03-01

    The contents of polychlorinated dibenzo- p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) in the soils of Moscow were estimated. The concentrations of PCDDs and PCDFs mainly vary in the range of 0.27-16.1 ng WHO-TEQ/kg with single points of very high contamination up to 57.3 ng WHO-TEQ/kg; the concentrations of PCBs are in the range of 2.1-50.8 ng/g with sites of high contamination up to 4020 ng/g. The contribution of dioxin-like PCBs to the total dioxin toxic equivalent is very high: from 16 to 85%. The high levels of PCDDs and PCDFs in the soils indicate the strong contamination of the atmospheric air. The main source of these compounds is apparently motor transport.

  2. Dioxin-like compound compositional profiles of furnace bottom ashes from household combustion in Poland and their possible associations with contamination status of agricultural soil and pine needles.

    PubMed

    Wyrzykowska, Barbara; Hanari, Nobuyasu; Orlikowska, Anna; Yamashita, Nobuyoshi; Falandysz, Jerzy

    2009-06-01

    A compositional profile of PCDDs, PCDFs, non- and mono-ortho PCBs, and PCNs of several type furnace bottom ashes obtained after the heating muffle stove for domestic use combustion of hard coal, coke, wood, and solid domestic waste mixture have been examined as possible contributors to environmental diffusion with these compounds in Poland. The uppermost concentration of dioxin-like compounds with 2.0 ng TEQ kg(-1) dry weight found for wood ash was dominated by PCDDs and PCDFs, while for other types of ashes were in the range from 0.052 ng TEQ kg(-1) to 0.67 ng TEQ kg(-1) dry weight. The multivariate statistical analysis displayed some compositional similarity of PCDDs, PCDFs and PCNs between the ashes and environmental pine needle or agricultural soil matrices collected in Poland. PMID:19356784

  3. Gender-related decrease in raven`s progressive matrices scores in children prenatally exposed to polychlorinated biphenyls and related contaminants

    SciTech Connect

    Guo, Y.L.; Lai, T.J.; Chen, S.J.; Hsu, C.C.

    1995-07-01

    Polychlorinated biphenyls (PCBs) and industrial mixtures that have been widely used throughout the world. PCBs have long environmental half lives and bioconcentrate, therefore contaminating soil, water, wild life, and human tissues. Typical human exposures come from environmental contamination of food supply, especially fresh water fish and meat, and occupational exposures. In certain uses, PCBs can partially oxidize and themselves become contaminated by extremely toxic compounds such as polychlorinated dibenzofurans (PCDFs). Two episodes of intoxication with heat-degraded PCBs have occurred, in Japan and Taiwan respectively. In 1979, over 2000 persons in Taiwan were intoxicated by heat-degraded PCBs that had contaminated their cooking oil. Kaneclor 500 (a Japanese PCB mixture) contained in the heating pipe was used as the heat transmitter. Leakage of the pipe introduced PCBs and heat-degraded products such as polychlorinated dibenzofurans (PCDFs) and polychlorinated quaterphenyls (PCQs) into the rice oil. Exposed victims developed chloracne, hyperpigmentation, peripheral neuropathy, and other signs and symptoms which were later called Yu-Cheng ({open_quotes}oil disease{close_quotes}) in Taiwan. These symptoms were caused not only by PCBs but by their heat degraded products, PCDFs. PCBs, PCDFs and PCDDs also can cross the placenta to affect the fetus and cause significant neurodevelopmental toxicity. Raven`s Colored Progressive Matrices (CPM) and Standarized Progressive Matrices (SPM) test spatial rather than verbal capabilities in children. These test are useful for determining whether prenatal exposure to PCBs/PCDFs cause differential effects on boys and girls. This paper reports results of CPM and SPM from age six to nine year in Yu-Cheng children and their matched controls. Cognative deficits up to 9 years of age were detected n children with prenatal exposure to PCBs and PCDFs, and boys were more affected than girls. 26 refs., 1 fig., 2 tabs.

  4. Modeling the partitioning and bioaccumulation of TCDD and other hydrophobic organic chemicals in lake Ontario

    SciTech Connect

    Endicott, D.D.; Cook, P.M.

    1994-01-01

    Lake trout and sediment data were used to define the biota-to-sediment ratio (BSR) for hydrophobic organic chemicals (HOCs) in Lake Ontario, including 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). The BSRs for bioaccumulative PCDD/PCDFs were found to be approximately two orders of magnitude (i.e., 100x) lower than for other HOCs of similar hydrophobicity. To evaluate this difference, a modeling framework is applied which accounts for the significant processes affecting BSR: bioaccumulation, partitioning, and sediment-water chemical distribution.

  5. NIST SRM 1945, whale blubber, NIST SRM 1974a, organics in mussel tissue, and NIST SRM 1941a, organics in marine sediment as certified reference materials for polychlorinated dioxins and furans in marine ecosystems.

    PubMed

    Chambers, L; Gardinali, P; Chambers, H; Wade, T L; Jackson, T; Brooks, J M

    1996-01-01

    Few natural matrix Standard Reference Materials are available for the validation of analytical methods measuring polychlorinated dioxins and furans (PCDDs and PCDFs) in marine ecosystems. The concentrations of PCDDs and PCDFs in NIST SRM 1945, SRM 1974a, and SRM 1941a are of interest because the analysis of marine mammal, mussel tissues and sediments have become important tools in the determination of organochlorine contamination of the environment. Because these SRMs have been demonstrated to be homogenous for other organic contaminants, they would be expected to be reliable standards for validation of polychlorinated dioxins and furans in marine mammals, mussels and sediments as well. PMID:8564434

  6. Control of PCDD/PCDF emissions from municipal-waste combustion systems (reannouncement)

    SciTech Connect

    Brna, T.G.; Kilgroe, J.D.

    1990-01-01

    The article gives results of tests on five modern municipal waste combustors (MWCs) to characterize or determine the performance of representative combustor types and associated air emission control systems in the regulatory development process. Test results for uncontrolled (combustor outlet) and controlled (flue gas cleaning system outlet) polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) are reported, along with pertinent information on other tests. The EPA is revising air pollutant emission rules for new MWCs and preparing guidelines for existing MWCs. These rules will limit emissions of PCDDs, PCDFs, CO2, and acid gases (HCl and SO2) as well as require tighter control of particulate matter emissions.

  7. Effect of metal catalysts on the formation of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran precursors (reannouncement)

    SciTech Connect

    Gullett, B.K.; Bruce, K.R.; Beach, L.O.

    1990-01-01

    The paper gives results of an examination of the catalytic effects of copper and iron compounds for their behavior in promoting formation of chlorine (Cl2), the major chlorinating agent of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), in an environment simulating that of municipal waste fly ash. Cl2 formed as a result of a metal-catalyzed reaction of HCl with O2. Catalytic activity was greatest at a temperature of about 400 C, supporting a theory of de novo synthesis of PCDDs and PCDFs on fly ash particles downstream of waste combustion.

  8. See the World on the Internet: Tips for Parents of Young Readers--and "Surfers" = Vea el mundo por Internet: Ideas por padres de jovenes lectores y exploradores.

    ERIC Educational Resources Information Center

    Moss, Jeanette

    Regardless of whether a parent has Internet access at home, it is essential that parents learn with their children and be aware of where their travels on the Internet are taking them. Many libraries have Internet workshops for parents or children or both. In the excitement of looking at sites, children may not even realize they are reading. Many…

  9. Verification and validation interim report for portable 1,000 CFM exhauster skids POR-007/Skid E and POR-008/Skid F

    SciTech Connect

    Nelson, O.D.

    1998-07-25

    This Verification and Validation (V/V) interim report summarizes to date the results of the V/V tasks performed in each of the following life cycle phases: concept, requirements, design, implementation, test, installation and checkout, and operation and maintenance. At the end of the installation and checkout phase, the V/V final report will be issued. This interim report contains or references the following for each phase: Description of V/V tasks performed; Summary of task results; Summary of anomalies and resolution; Assessment of system quality; Recommendations.

  10. ENVIRONMENTAL CONTAMINATION BY POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS ASSOCIATED WITH PULP AND PAPER MILL DISCHARGE

    EPA Science Inventory

    Sludge from seven pulp and paper mills was analyzed for 2,3,7,8-TCDD. The level of contamination ranged from not detectable (1pg/g) to over 400 pg/g. Analyses for other planar polychlorinated contaminants indicated high levels of contamination by other PCDDs and PCDFs. Polychlori...

  11. RISK FROM EXPOSURE TO POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS EMITTED FROM MUNICIPAL INCINERATORS

    EPA Science Inventory

    Incineration of wastes seems to be one of the major sources of PCDDs and PCDFs (dioxins). heir prevalence and extreme stability in the environment, bioavailability and bioaccumulation in the biota and human adipose tissues and breast milk are of much concern. ,3,7,8-TCDD is one o...

  12. Framework for Application of the Toxicity Equivalence Methodology for Polychlorinated Dioxins, Furans, and Biphenyls in Ecological Risk Assessment (Final)

    EPA Science Inventory

    Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) are persistent contaminants found widely in the environment. Several of these compounds bioaccumulate in the tissues of fish, birds, and mammals and have been shown to cause mortality and adver...

  13. Aerosat sampling of PCDD/PCDF emissions from the Gulf oil spill in situ burns

    EPA Science Inventory

    Emissions from the in situ burning of oil in the Gulf of Mexico after the catastrophic failure of the Deepwater Horizon drilling platform were sampled for polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDDs/PCDFs). A battery-operated instrument package was lo...

  14. EVALUATION OF METHODOLOGY FOR DETERMINATION OF POLYHALOGENATED DIBENZO-P-DIOXINS AND DIBENZOFURANS IN AMBIENT AIR

    EPA Science Inventory

    General Metals works PS-1 PUF air samplers and an analytical method based on high resolution gas chromatography - high resolution mass spectrometry (HRGC-HRMS) were evaluated for determination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs) and polybrominated...

  15. Vertical distribution of AhR-activating compounds in sediments contaminated by modernized pulp and paper industry.

    PubMed

    Ratia, H; Oikari, A

    2014-03-01

    Increased ethoxyresorufin-O-deethylase (EROD) activity is a sensitive biomarker of exposure to the chemicals which activate the aryl hydrocarbon receptor (AhR) and induce the cytochrome P450 system, such as many polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs). Pulp bleaching was one of the main sources of PCDDs and PCDFs until elemental chlorine free (ECF) and total chlorine free bleaching processes since 1990s have remarkably decreased but not completely eliminate discharges of these chemicals. In addition, historically contaminated sediments may act as a source of these persistent contaminants. In this study, the contamination history and recovery of a watercourse heavily loaded by the chemical wood industry were studied by analyzing PCDDs, PCDFs and PCBs from vertical sediment samples and by measuring hepatic EROD activity from rainbow trout intraperitoneally dosed with the sediment extracts. No PCDDs or PCDFs were found above the chromatographic limit of detection from the study area and only small amounts of PCB congeners 101, 138, 153, and 180 were present. No increased EROD activity was observed in fish indicating the absence of any AhR-activating compounds in the surface sediment, to about 15 cm depth, representing about the last 20 years when kraft pulping and ECF bleaching with activated wastewater treatment have been used. It can be concluded that nowadays organochlorines and other AhR-ligands do not harm the previously heavily polluted watercourse. PMID:24361517

  16. POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS: CORRELATION BETWEEN IN VITRO AND IN VIVO STRUCTURE ACTIVITY RELATIONSHIPS (SARS)

    EPA Science Inventory

    Polychlorinated dibenzofurans (PCDFs) and dibenzo-p-dioxins (PCDDs) elicit a number of common biologic and toxic responses which are triggered by their initial binding to a cytosolic receptor protein. hese effects include the induction of several cytochrome P-448 dependent monoox...

  17. SAMPLING AND ANALYSIS FOR POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS IN AMBIENT AIR

    EPA Science Inventory

    A short-term study for determination of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in ambient air in Green Bay, Wisconsin, has been completed. eneral Metals Works PS-1 air samplers equipped with particle filters and polyurethane foam (PUF)...

  18. Optimization of separation and detection conditions for comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are among the most toxic compounds known. The current predominant method of analysis is too expensive and cumbersome, and comprehensive gas chromatography coupled to time-of-flight mass spect...

  19. DIBENZO-P-DIOXINS IN THE ENVIRONMENT FROM CERAMICS AND POTTERY PRODUCED FROM BALL CLAY MINED IN THE U.S.

    EPA Science Inventory

    Processed ball clay samples used in the production of ceramics and samples of the ceramic products were collected and analyzed for the presence and concentration of the 2,3,7,8-Cl substituted polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs). The processed ball clay had...

  20. AN ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) FOR DETERMINING DIOXINS IN SEDIMENT AND SOIL SAMPLES

    EPA Science Inventory

    The dioxins comprise a family of compounds chemically referred to as polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The most toxic of these compounds is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a known human carcinogen. Dioxins are formed ...

  1. EVALUATION OF THE FULL-SCALE BASE CATALYZED DECOMPOSITION PROCESS (BCDP) UNIT LOCATED IN GUAM

    EPA Science Inventory

    This report summarizes performance data collected in February 1997 on the removal of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) from soil fed to a first-stage rotary kiln reactor of the Base Catalyzed Dec...

  2. Sources and fate of polychlorinated dibenzodioxins, dibenzofurans and related compounds in human environments.

    PubMed

    Tiernan, T O; Taylor, M L; Garrett, J H; VanNess, G F; Solch, J G; Wagel, D J; Ferguson, G L; Schecter, A

    1985-02-01

    Several of the major incidents resulting in potential human exposures to polychlorinated dibenzodioxins (PCDDs) and/or polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and related compounds which have occurred in the U.S. in recent periods have resulted from improper disposal of hazardous chemical wastes. Prominent examples of such environmental contamination episodes are the Love Canal, into which ton quantities of chlorinated organic compounds containing substantial concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were deposited; numerous sites in the State of Missouri which were contaminated by the dumping of chlorinated organic wastes containing various PCDDs and possibly PCDFs, and PCBs; and the environs of a 2,4-D/2,4,5-T manufacturing plant site in Arkansas, which were contaminated with PCDDs. Environmental assessments of such sites have revealed extensive contamination of soils, waterways, fish and other biological species with these toxic compounds, which in turn could lead to human exposures. Other recently identified sources of PCDDs, PCDFs and related compounds in human environments include stack effluents from municipal refuse incineration, and fires and explosions involving electrical devices containing PCBs and polychlorinated benzenes. Data obtained in assessments of such incidents are presented, and the implications of these findings with respect to the distribution and persistence of PCDDs, PCDFs and related chemicals in the environment and possible effects on humans are discussed. PMID:3921357

  3. Sources and fate of polychlorinated dibenzodioxins, dibenzofurans and related compounds in human environments

    SciTech Connect

    Tiernan, T.O.; Taylor, M.L.; Garrett, J.H.; VanNess, G.F.; Solch, J.G.; Wagel, D.J.; Ferguson, G.L.; Schecter, A.

    1985-02-01

    Several of the major incidents resulting in potential human exposures to polychlorinated dibenzodioxins (PCDDs) and/or polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and related compounds which have occurred in the U.S. in recent periods have resulted from improper disposal of hazardous chemical wastes. Prominent examples of such environmental contamination episodes are the Love Canal, into which ton quantities of chlorinated organic compounds containing substantial concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were deposited; numerous sites in the State of Missouri which were contaminated by the dumping of chlorinated organic wastes containing various PCDDs and possibly PCDFs, and PCBs; and the environs of a 2,4-D/2,4,5-T manufacturing plant site in Arkansas, which were contaminated with PCDDs. Environmental assessments of such sites have revealed extensive contamination of soils, waterways, fish and other biological species with these toxic compounds, which in turn could lead to human exposures. Other recently identified sources of PCDDs, PCDFs and related compounds in human environments include stack effluents from municipal refuse incineration, and fires and explosions involving electrical devices containing PCBs and polychlorinated benzenes. Data obtained in assessments of such incidents are presented, and the implications of these findings with respect to the distribution and persistence of PCDDs, PCDFs and related chemicals in the environment and possible effects on humans are discussed.

  4. Dioxins, dioxin-like compounds, and PBDEs in the U.S. domestic meat supply: trends and levels 2003 to 2013

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the mid-1990s, 2002-2003, 2007-2008, and again in 2012-2013 the U.S. Department of Agriculture (USDA) conducted statistical surveys for dioxin and dioxin-like compound (PCDDs, PCDFs, and PCBs) residues in domestic meat and poultry. The surveys were conducted to determine background levels of diox...

  5. ISOMER DEPENDENT BIOAVAILABILITY OF POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS FROM MUNICIPAL INCINERATOR FLY ASH TO CARP

    EPA Science Inventory

    The isomer dependent bioavailability of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans (PCDDs and PCDFs) from municipal incinerator fly ash to freshwater fish was determined. It was observed that carp exposed to fly ash in a continuous flow exposure readily accumulated selec...

  6. Sources and fate of polychlorinated dibenzodioxins, dibenzofurans and related compounds in human environments.

    PubMed Central

    Tiernan, T O; Taylor, M L; Garrett, J H; VanNess, G F; Solch, J G; Wagel, D J; Ferguson, G L; Schecter, A

    1985-01-01

    Several of the major incidents resulting in potential human exposures to polychlorinated dibenzodioxins (PCDDs) and/or polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and related compounds which have occurred in the U.S. in recent periods have resulted from improper disposal of hazardous chemical wastes. Prominent examples of such environmental contamination episodes are the Love Canal, into which ton quantities of chlorinated organic compounds containing substantial concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were deposited; numerous sites in the State of Missouri which were contaminated by the dumping of chlorinated organic wastes containing various PCDDs and possibly PCDFs, and PCBs; and the environs of a 2,4-D/2,4,5-T manufacturing plant site in Arkansas, which were contaminated with PCDDs. Environmental assessments of such sites have revealed extensive contamination of soils, waterways, fish and other biological species with these toxic compounds, which in turn could lead to human exposures. Other recently identified sources of PCDDs, PCDFs and related compounds in human environments include stack effluents from municipal refuse incineration, and fires and explosions involving electrical devices containing PCBs and polychlorinated benzenes. Data obtained in assessments of such incidents are presented, and the implications of these findings with respect to the distribution and persistence of PCDDs, PCDFs and related chemicals in the environment and possible effects on humans are discussed. PMID:3921357

  7. Passive Sampling Provides Evidence for Neward Bay as a Source of Polychlorinated Dibenzo-p-Dioxins and Furans to the New York/New Jersey, USA, Atmosphere

    EPA Science Inventory

    Freely dissolved and gas phase polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were measured in the water column and atmosphere at five locations within Newark Bay (New Jersey, USA) from May 2008 to August 2009 with polyethylene (PE) passive ...

  8. FRAMEWORK FOR APPLICATION OF THE TOXICITY EQUIVALENCE METHODOLOGY FOR POLYCHLORINATED DIOXINS, FURANS, AND BIPHENYLS IN ECOLOGICAL RISK ASSESSMENT

    EPA Science Inventory

    Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenols (PCBs) commonly occur as complex mixtures in the environment, including in animal tissues. For more than a decade the USEPA and other organizations have estimated the combined risks that such mixtures...

  9. THE CONCENTRATION AND DISTRIBUTION OF 2,3,7,8-DIBENZO-P-DIOXINS / - FURANS IN CHICKENS

    EPA Science Inventory

    The concentrations of 2,3,7,8-Cl substituted dibenzo-p-dioxins/-furans (PCDDs/PCDFs) were determined in the edible tissues of whole chicken fryers and compared with the values found in their abdominal fat. The values are presented both on a whole weight basis and on a lipid-adju...

  10. DETERMINATION OF THE VAPOR PRESSURES OF SELECT POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS AT 75–275°C

    EPA Science Inventory

    Vapor pressures were determined for several polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) at 75–275°C, extending the available literature data to more relevant temperature regions and providing the first experimental data for 2,3,7...

  11. Emissions from Open burning of Used Agricultural Pesticide Containers

    EPA Science Inventory

    Emissions from simulated open burning of used agricultural pesticide containers were sampled for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs), polycyclic aromatic hydrocarbon compounds (PAHs), and particle matter (PM10 and PM2.5). Clean high density polyethyl...

  12. EFFECT OF SOOT AND COPPER COMBUSTOR DEPOSITS ON DIOXIN EMISSIONS

    EPA Science Inventory

    An experimental study was conducted to investigate the effects of residual soot and copper combustor deposits on the formation of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) during the combustion of a chlorinated waste. In a bench-scale set...

  13. EVALUATION OF A SAMPLING AND ANALYSIS METHOD FOR DETERMINATION OF POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS IN AMBIENT AIR

    EPA Science Inventory

    General Metals Works PS-1 PUF air samplers and an analytical method based on high esolution gas chromatography - high resolution mass spectrometry (HRGC-HRMS) were valuated for determination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs), polybrominated dibe...

  14. Quantitative structure-property relationships on photolysis of PCDD/Fs adsorbed to spruce (Picea abies (L.) Karst.) needle surfaces under sunlight irradiation.

    PubMed

    Niu, Junfeng; Huang, Liping; Chen, Jingwen; Yu, Gang; Schramm, Karl-Werner

    2005-02-01

    By partial least squares (PLS) regression, quantitative structure-property relationship (QSPR) models were developed for photolysis half-life (t1/2) of PCDD/Fs and PAHs sorbed to spruce (Picea abies (L.) Karst.) needle surfaces and irradiated by sunlight. Quantum chemical descriptors computed by PM3 Hamiltonian were used predictor variables. PLS analysis for the PCDDs and PAHs respectively resulted in no correlation by our statistical methods. The cross-validated Qcum2 value for the optimal QSPR model of PCDFs is 0.722, indicating a good predictive ability for logt1/2 of PCDFs adsorbed to spruce needle surfaces. The QSPR results show that the number of chlorine atoms bonded to the parent structure and (E(LUMO)-E(HOMO))2 has a dominant effect on t1/2 values of PCDFs. Increasing the number of chlorine atoms and (E(LUMO)-E(HOMO))2 values leads to increase of logt1/2 values of PCDFs. PMID:15639263

  15. KEY PARAMETERS FOR DE NOVO FORMATION OF POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS

    EPA Science Inventory

    De novo formation of polychlorinated- dibenzo-p-dioxins and dibenzofurans (PCDDs and PCDFs) was investigated in an Entrained Flow Reactor (EFR) to simulate combustion conditions. The parameters investigated were carbon content and nature in fly ash; type of gas- phase environment...

  16. Prediction for thermodynamic function of dioxins for gas phase using semi-empirical molecular orbital method with PM3 Hamiltonian.

    PubMed

    Saito, N; Fuwa, A

    2000-01-01

    In this investigation, respective thermodynamic parameters of heats of formation, standard entropy and specific heat capacity at constant pressure for PCDDs, PCDFs, Co-PCB and PCBs as well as polychlorinated-benzenes and polychlorinated-phenols have been evaluated by quantum chemical calculation using a semi-empirical molecular orbital method with the PM3 Hamiltonian and statistical thermodynamic correlation. PMID:10665426

  17. Dioxin, furan, PCB, and PBDE levels in U.S. foods: Survey trends and consumer exposure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The U.S. Department of Agriculture, Agricultural Research Service (USDA-ARS) and Food Safety and Inspection Service (USDA-FSIS) have conducted statistical surveys for dioxins (PCDDs, PCDFs, and PCBs) and polybrominated diphenyl ethers every 5 years since the mid-1990s (mid-1990s, 2002-3, 2007-8). I...

  18. MECHANISTIC STEPS IN THE PRODUCTION OF PCDD AND PCDF DURING WASTE COMBUSTION

    EPA Science Inventory

    Research has shown that synthesis of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) during municipal waste combustion can proceed through a three step mechanism including 1) production of Cl2 from a metal-catalyzed reaction of HCl a...

  19. EXTENSION OF U.S. EPA METHODS 0023A/8290 TO INCLUDE 13C12-LABELLED MONO-, DI-, AND TRI-CHLORINATED DIBENZO-P-DIOXIN AND DIBENZOFURAN STANDARDS

    EPA Science Inventory

    Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are typically reported only in terms of the tetra-through octa-CDD/CDF isomers, either as homologue sums or as subsets thereof. This practice is common because the toxic isomers ...

  20. Framework for Application of the Toxicity Equivalence Methodology for Polychlorinated Dioxins, Furans, and Biphenyls in Ecological Risk Assessment

    EPA Science Inventory

    Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) are commonly found as contaminants in complex mixtures in the environment. Several of these compounds bioaccumulate in the tissues of fish, birds, and mammals and have been shown to cause mo...

  1. CONTROL OF DIOXIN, FURAN, AND MERCURY EMISSIONS FROM MUNICIPAL WASTE COMBUSTORS

    EPA Science Inventory

    There is a significant public and scientific concern over the potential risks of air pollution emissions from municipal waste combustors (MWCs). The primary pollutants of concern are polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs), and mercury (Hg). Depending on...

  2. MECHANISTIC STEPS IN THE PRODUCTION OF PCDD AND PCDF DURING WASTE COMBUSTION

    EPA Science Inventory

    The paper discusses work involving a reactor that simulates the down-stream flue gas conditions of a waste combustor and an analytical laboratory to investigate the formation mechanisms of polychlorinated dibenzo-p-dioxins (PCDDS) and polychlorinated dibenzofurans (PCDFS) to deve...

  3. Adsorption of polychlorinated dibenzo-p-dioxins/dibenzofurans on activated carbon from hexane.

    PubMed

    Zhou, Xu-Jian; Buekens, Alfons; Li, Xiao-Dong; Ni, Ming-Jiang; Cen, Ke-Fa

    2016-02-01

    Activated carbon is widely used to abate dioxins and dioxin-like compounds from flue gas. Comparing commercial samples regarding their potential to adsorb dioxins may proceed by using test columns, yet it takes many measurements to characterise the retention and breakthrough of dioxins. In this study, commercial activated carbon samples are evaluated during tests to remove trace amounts of dioxins dissolved in n-hexane. The solution was prepared from fly ash collected from a municipal solid waste incinerator. The key variables selected were the concentration of dioxins in n-hexane and the dosage of activated carbon. Both polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) showed very high removal efficiencies (94.7%-98.0% for PCDDs and 99.7%-99.8% for PCDFs). The presence of a large excess of n-hexane solvent had little effect on the removal efficiency of PCDD/Fs. The adsorbed PCDD/Fs showed a linear correlation (R(2) > 0.98) with the initial concentrations. Comparative analysis of adsorption isotherms showed that a linear Henry isotherm fitted better the experimental data (R(2) = 0.99 both for PCDDs and PCDFs) than the more usual Freundlich isotherm (R(2) = 0.88 for PCDDs and 0.77 for PCDFs). Finally, the results of fingerprint analysis indicated that dioxin fingerprint (weight proportion of different congeners) on activated carbon after adsorption did not change from that in hexane. PMID:26476048

  4. THE EFFECT OF METAL CATALYSTS ON THE FORMATION OF POLYCHLORINATED DIBENZO-P-DIOXIN AND POLYCHLORINATED DIBENZOFURAN PRECURSORS

    EPA Science Inventory

    The catalytic effects of copper and iron compounds were examined for their behavior in promoting formation of chlorine (Cl2), the major chlorinating agent of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), in an environment simulati...

  5. Polychlorinated dibenzofurans and dibenzo-p-dioxins in subsurface soil, superficial dust, and air extracts from a contaminated landfill.

    PubMed

    Hansen, L G; O'Keefe, P W

    1996-08-01

    Extracts of soil, dust and air from a National Priorities List Landfill have been found to contain distinct profiles of polychlorinated biphenyls (PCBs). The different extracts show subtle differences in toxicities and the soil extract has been shown to cause both Ah receptor mediated effects and Ah receptor independent effects in immature female rats. Evidence of open burning at the site dictated quantitation of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) for a more accurate tabulation of dioxin equivalencies. High volume air sampling on XAD-2 resin cartridges captured trace amounts of PCDFs and no detectable PCDDs. Acetone:Hexane (1:1) extracts of soil and dust contained 762 microg/ml and 250 microg/ml PCDFs, respectively, and less than 10% as much PCDD. Subsequent benzene:methylene chloride (1:1) extracts were enriched in coplanar compounds relative to total PCBs. PCDF:PCB ratios in all extracts were higher than in the rice oils contaminated with heated PCBs in the Yusho and Yu-Cheng incidents. No 2,3,7,8-TCDD was detected, and total PCB+PCDD+PCDF toxic equivalencies were dominated by the high proportions of PCDFs. PMID:8785012

  6. Journal Article: Atmospheric Measurements of CDDs, CDFs, and Coplanar PCBs in Rural and Remote Locations of the U.S. for the Years 1998-2001 from the National Dioxin Air Monitoring Network (Ndamn)

    EPA Science Inventory

    The U.S. EPA established a National Dioxin Air Monitoring Network (NDAMN) to determine background air concentrations of PCDDs, PCDFs, and cp-PCBs in rural and remote areas of the United States. Background is defined as average ambient air concentrations inferred from long-term a...

  7. FORMATION OF POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS FROM A MIXTURE OF CHLOROPHENOLS OVER FLY ASH: INFLUENCE OF WATER VAPOR

    EPA Science Inventory

    To offer a polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) parameter for plant operation control, the on-line estimation of PCDD/Fs emissions by surrogates like chlorophenols is useful. Formation of PCDD/Fs over fly ash was studied in an isothermal (310 degree...

  8. A Survey of Polychlorinated Dibenzo-p-dioxins, Polychlorinated Dibenzofurans and Co-planar Polychlorinated Biphenyls in U.S. Meat and Poultry, 2007-2008

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A statistically-based survey of dioxins and dioxin-like compounds in domestic meat and poultry was conducted by the U.S. Department of Agriculture (USDA) from September 2007 to September 2008. Seventeen toxic polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and three coplanar pol...

  9. Ensenando El Espanol por Medio de Accion (Teaching Spanish through Action).

    ERIC Educational Resources Information Center

    Segal, Bertha

    A teaching guide containing 102 elementary to intermediate level Spanish lessons is presented. The lessons are based on the Total Physical Response technique of second language teaching. They follow the stages of first language acquisition: listening, speaking, and reading. Each of the ten units contains a list of new vocabulary words, individual…

  10. El Libro de la Escritura por Pinguino Tinto (The Writing Book, by Inky Penguin).

    ERIC Educational Resources Information Center

    Padgett, Ron

    Presented completely in Spanish and intended for elementary level students, this book offers 12 writing ideas and several suggestions on how students can make a book using their writing. Each writing idea is presented with a brief description (addressed to the student), several examples of student writing, and a blank page on which to write.…