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Sample records for ferrocyanide reactivity effects

  1. Effect of potential waste constituents on the reactivity of Hanford ferrocyanide wastes: Diluent, catalyst, and initiator studies

    Scheele, R.D.; Johnston, J.W.; Tingey, J.M.; Burger, L.L.; Sell, R.L.

    1993-04-01

    During the 1980s, scientists at the Hanford Site began considering disposal options for wastes in underground storage tanks. As a result of safety concerns, it was determined that special consideration should be given to ferrocyanide-bearing wastes to ensure their continued safe storage. In addition, Westinghouse Hanford Company (WHC) chartered Pacific Northwest Laboratory (PNL) to determine the conditions necessary for vigorous reactions to occur in the Hanford Site ferrocyanide wastes. As part of those studies, PNL has evaluated the effects of selected potential waste constituents to determine how they might affect the reactivity of the wastes. The authors' investigations of the diluent, catalytic, or initiating effects of potential waste constituents included studies (1) to determine the effect of the oxidant-to-ferrocyanide ratio, (2) to establish the effect of sodium aluminate concentration, (3) to identify materials that could affect the explosivity of a mixture of sodium nickel ferricyanide (a potential aging product of ferrocyanide) and sodium nitrate and nitrite, (4) and to determine the effect of nickel sulfide concentration. They also conducted a thermal sensitivity study and analyzed the results to determine the relative behaviors of sodium nickel ferrocyanide and ferricyanide. A statistical evaluation of the time-to-explosion (TTX) test results from the catalyst and initiator screening study found that the ferricyanide reacted at a faster rate than did the ferrocyanide analog. The thermal analyses indicated that the ferricyanide form is more thermally sensitive, exhibiting exothermic behavior at a lower temperature than the ferrocyanide form. The increased thermal sensitivity of the ferricyanide, which is a potential oxidation product of ferrocyanide, relative to the ferrocyanide analog, does not support the hypothesis that aging independent of the reaction pathway will necessarily reduce the reaction hazard of ferrocyanide wastes

  2. Effect of potential Hanford ferrocyanide waste constituents on the reaction between ferrocyanide and nitrates/nitrites

    Scheele, R.D.; Burger, L.L.; Sell, R.L.

    1993-02-01

    During the 1950s, ferrocyanide- and nitrate-bearing wastes were produced at Hanford. A concern about continued safe storage and future treatment of these wastes has arisen because ferrocyanide and nitrate mixtures can explode when heated. Because of this concern, the Pacific Northwest Laboratory has performed experimental studies to determine the conditions needed to continue storing the wastes safely. In this paper, we present the results of our studies on the effects of other potential ferrocyanide waste constituents on the explosivity of mixtures of sodium nickel ferrocyanide and sodium nitrate and nitrite. In particular, this paper presents the results of investigations on the diluent effects of equimolar sodium nitrate and nitrite, sodium nickel ferrocyanide, and sodium aluminate, and the catalyst or initiator effects of nickel sulfide

  3. Hanford ferrocyanide waste chemistry and reactivity preliminary catalyst and initiator screening studies

    Scheele, R.D.; Bryan, S.A.; Johnston, J.W.; Tingey, J.M.; Burger, L.L.; Hallen, R.T.

    1992-05-01

    During the 1950s, ferrocyanide was used to scavenge radiocesium from aqueous nitrate-containing Hanford wastes. During the production of defense materials and while these wastes were stored in high-level waste tanks at the Hanford Site, some of these wastes were likely mixed with other waste constituents and materials. Recently, Pacific Northwest Laboratory (PNL) was commissioned by Westinghouse Hanford Company (WHC) to investigate the chemical reactivity of these ferrocyanide-bearing wastes. Because of known or potential thermal reactivity hazards associated with ferrocyanide- and nitrate-bearing wastes, and because of the potential for different materials to act as catalysts or initiators of the reactions about which there is concern, we at PNL have begun investigating the effects of the other potential waste constituents. This report presents the results of a preliminary screening study to identify classes of materials that might be in the Hanford high-level waste tanks and that could accelerate or reduce the starting temperature of the reaction(s) of concern. We plan to use the resulted of this study to determine which materials or class of materials merit additional research

  4. FY 1993 Ferrocyanide Tank Safety Project: Effects of Aging on Ferrocyanide Wastes test plan for the remainder of FY 1993

    Lilga, M.A.; Schiefelbein, G.F.

    1993-06-01

    Researchers in the Hanford Ferrocyanide Task Team are studying safety issues associated with ferrocyanide precipitates in single shell waste storage tanks (SST). Ferrocyanide is a stable complex of ferrous, ion and cyanide ion that is considered nontoxic because it does not dissociate readily in aqueous solutions. However, in the laboratory at temperatures in excess of 180 degrees C and in the presence of oxidizers such as nitrates and nitrites, dry ferrocyanide and ferrocyanide waste stimulants can be made to react exothermically. The Ferrocyanide Safety Project at the Pacific Northwest Laboratory (PNL) is part of the Waste Tank Safety Program at Westinghouse Hanford Company (WHC). The purpose of the WHC program is to (1) maintain the ferrocyanide tanks with minimal risk of an accident, (2) select one or more strategies to assure safe storage, and (3) close out the unreviewed safety question (USQ). Tank ferrocyanide wastes were exposed to highly alkaline wastes from subsequent processing operations. Chemical reactions with caustic may have changed the ferrocyanide materials during 40 years of storage in the SSTs. Research in the open-quotes Effects of Aging on Ferrocyanide Wastesclose quotes task is targeted at studying aging of ferrocyanide tank simulants and other ferrocyanide materials to obtain a better understanding of how tank materials may have changed over the years. The research objective in this project is to determine the solubility and hydrolysis characteristics of simulated ferrocyanide tank wastes in alkaline media. The behavior of ferrocyanide simulant wastes is being determined by performing chemical reactions under conditions that might mimic the potential ranges in SST environments. Experiments are conducted at high pH, at high ionic strength, and in the presence of gamma radiation. Verification of simulant study findings by comparison with results with actual waste will also be required

  5. Chemical reactivity of potential ferrocyanide precipitates in Hanford tanks with nitrates and nitrites

    Scheele, R.D.; Burger, L.L.; Tingey, J.M.; Hallen, R.T.; Lilga, M.A.

    1992-01-01

    Ferrocyanide-bearing wastes were produced at the Hanford Site during the 1950s. Safe storage of these wastes has recently drawn increased attention. As a result of these concerns, the Pacific Northwest Laboratory was chartered to investigate the chemical reactivity and explosivity of the ferrocyanide-bearing wastes. We have investigated the thermal sensitivity of synthetic wastes and ferrocyanides and observed oxidation at 130 deg. C and explosions down to 295 deg. C. Coupled with thermodynamic calculations, these thermal studies have also shown a dependence of the reactivity on the synthetic waste composition, which is dependent on the solids settling behavior. (author)

  6. Effect of indifferent anions on reactions of cadmium ferrocyanide precipitation

    Gyunner, Eh A; Mel' nichenko, L M; Vel' mozhnyj, I S [Simferopol' skij Gosudarstvennyj Univ. (Ukrainian SSR)

    1982-08-01

    To clarify the effect of indifferent anions on the processes of cadmium ferrocyanide precipitation the interaction in six systems of the type CdXsub(m)-Msub(4)R-Hsub(2)O (X-Cl/sup -/, CH/sub 3/COO/sup -/, SO/sub 4//sup 2 -/; M-K/sup +/, NH/sub 4//sup +/; R-(Fe(CN)/sub 6/)/sup 4 -/) is studied using the methods of physicochemical analysis (the method of residual concentrations, refractometry). Composition and formation regions of low-soluble interaction products are determined. Effect of anion X nature on interaction character is stated in the series Cl/sup -/, CH/sub 3/COO/sup -/, SO/sub 4//sup 2 -/ in mixtures with incomplete Cd/sup 2 +/ precipitation a tendency for the increase of Cd/sup 2 +/:R/sup 4 -/ ratios in precipitates formed is observed.

  7. Ferrocyanide tank waste stability

    Fowler, K.D.

    1993-01-01

    Ferrocyanide wastes were generated at the Hanford Site during the mid to late 1950s as a result of efforts to create more tank space for the storage of high-level nuclear waste. The ferrocyanide process was developed to remove 137 CS from existing waste and newly generated waste that resulted from the recovery of valuable uranium in Hanford Site waste tanks. During the course of research associated with the ferrocyanide process, it was recognized that ferrocyanide materials, when mixed with sodium nitrate and/or sodium nitrite, were capable of violent exothermic reaction. This chemical reactivity became an issue in the 1980s, when safety issues associated with the storage of ferrocyanide wastes in Hanford Site tanks became prominent. These safety issues heightened in the late 1980s and led to the current scrutiny of the safety issues associated with these wastes, as well as current research and waste management programs. Testing to provide information on the nature of possible tank reactions is ongoing. This document supplements the information presented in Summary of Single-Shell Tank Waste Stability, WHC-EP-0347, March 1991 (Borsheim and Kirch 1991), which evaluated several issues. This supplement only considers information particular to ferrocyanide wastes

  8. Investigation of reactivity of inorganic free radicals relative to ferrocyanide- and octacyanomolybdate-ions in aqueous solutions by the method of pulse radiolysis

    Gogolev, A.V.; Fedoseev, A.M.; Makarov, I.F.; Pikaev, A.K.

    1989-01-01

    In aqueous solutions by the method of pulse radiolysis (dose per impulse-7.96-47.8 Gy, electron energy-5 MeV) the reactivity of Cl 2 - , Br 2 - , I 2 - , (SCN) 2 - , CO 3 - , SeO 3 - , SO 4 - radicals towards ferrocyanide ions and of Br 2 - , CO 3 - , SO 4 - radicals tawards octacyanomolybdate ions is studied. Linear dependence of rate constant logarithm of Cl 2 - , Br 2 - , I 2 - reactions with cyanide complexes on the difference of redox potentials of reacting particles ΔE 0 is obtained. Radicals containing oxygen react with cyanide complexes more rapidly than can be expected on the basis of ΔE 0 values. The effect of solution ionic strength, charge of reacting particles and radical nature on the reaction rate is discussed

  9. Effect of organic complexing compounds and surfactants on coprecipitation of cesium radionuclides with nickel ferrocyanide precipitate

    Milyutin, V.V.; Gelis, V.M.; Ershov, B.G.; Seliverstov, A.F.

    2008-01-01

    One studied the effect of the organic complexing compounds and of the surfactants on the coprecipitation of Cs trace amounts with the nickel ferrocyanide precipitate. The presence of the oxalate- and ethylenediamin-tetraacetate-ions in the solutions is shown to result in the abrupt reduction of Cs coprecipitation degree. The effect of the various surfactants manifested itself not so explicitly. To reduce the negative effect of the organic compounds on the intimacy of Cs coprecipitation one tried out the procedure of their chemical destruction by ozon. Pre-ozonization of the solutions enabled to prevent the negative effect of the organic complexing compounds and of the surfactants on Cs coprecipitation with nickel ferrocyanide precipitate [ru

  10. Effect on Cs removal of solid-phase metal oxidation in metal ferrocyanides

    Lee, Keun-Young; Kim, Jimin; Oh, Maengkyo; Lee, Eil-Hee; Kim, Kwang-Wook; Chung, Dong-Yong; Moon, Jei-Kwon [Korea Atomic Energy Research Institute (KAERI), Daejeon (Korea, Republic of).

    2017-07-01

    Metal ferrocyanides (MFCs) have been studied for many years and are regarded as efficient adsorbents for the selective removal of radioactive cesium (Cs) from contaminated aqueous solutions. Although their efficiency has been demonstrated, various investigations on the physicochemical, thermal, and radiological stability of the solids of MFCs are required to enhance the applicability of MFCs in the treatment process. We observed that the Cs adsorption efficiencies of cobalt and nickel ferrocyanides decreased as their aging period increased, while the Cs adsorption efficiencies of copper and zinc ferrocyanides did not decrease. The tendencies of these ferrocyanides were accelerated by exposure of the solids at a higher temperature for a longer time. Our comprehensive analyses demonstrated that only the oxidizable metals in the MFCs can be oxidized by aging time and increasing temperature; also, this affects the Cs removal efficiency by decreasing the exchangeable sites in the solids. The chemical stability of MFCs is very important for the optimization of the synthesis and storage conditions.

  11. Ferrocyanide Safety Project Task 3 Ferrocyanide Aging Studies FY 1993 annual report

    Lilga, M.A.; Lumetta, M.R.; Schiefelbein, G.F.

    1993-10-01

    The Hanford Ferrocyanide Task Team is addressing issues involving ferrocyanide precipitates in single-shell waste storage tanks (SSTs), in particular the storage of waste in a safe manner. This Task Team, composed of researchers from Westinghouse Hanford Company (WHC), Pacific Northwest Laboratory (PNL), and outside consultants, was formed in response to the need for an updated analysis of safety questions about the Hanford ferrocyanide tanks. The Ferrocyanides Safety Project at PNL is part of the Waste Tank Safety Program led by WHC. The overall purpose of the WHC program, sponsored by the US Department of Energy's Tank Farm Project Office, is to (1) maintain the ferrocyanide tanks with minimal risk of an accident, (2) select one or more strategies to assure safe storage, and (3) close out the unreviewed safety question (USQ). This annual report gives the results of the work conducted by PNL in FY 1993 on Task 3, Ferrocyanides Aging Studies, which deals with the aging behavior of simulated ferrocyanide wastes. Aging processes include the dissolution and hydrolysis of nickel ferrocyanides in high pH aqueous solutions. Investigated were the effects of pH variation; ionic strength and sodium ion concentration; the presence of anions such as phosphate, carbonate, and nitrate; temperature; and gamma radiation on solubility of ferrocyanide materials including In-Farm-lA, Rev. 4 flowsheet-prepared Na 2 NiFe(CN) 6

  12. The effect of the synthesis method on the parameters of pore structure and selectivity of ferrocyanide sorbents based on natural minerals

    Voronina, A.V.; Gorbunova, T.V.; Semenishchev, V.S.

    2017-01-01

    Ferrocyanide sorbents were obtained via thin-layer and surface modification of natural clinoptilolite and marl. The effect of modification method on surface characteristics of these sorbents and their selectivity for cesium was studied. It was shown that the modification resulted in an increase of selectivity of modified ferrocyanide sorbents to cesium as compared with the natural clinoptilolite in presence of Na + , as well as in an increase of cesium distribution coefficients in presence of K + . The nickel-potassium ferrocyanide based on the clinoptilolite showed the highest selectivity for cesium at sodium concentrations of 10 -4 -2 mol L -1 : cesium distribution coefficient was lg K d = 4.5 ± 0.4 L kg -1 and cesium/sodium separation factor was α(Cs/Na) = 250. In the presence of NH 4 + , all modified sorbents showed approximately equal selectivity for 137 Cs. Probable applications of the sorbents were suggested. (author)

  13. Ferrocyanide safety program: Final report on adiabatic calorimetry and tube propagation tests with synthetic ferrocyanide materials

    Fauske, H.F.; Meacham, J.E.; Cash, R.J.

    1995-01-01

    Based on Fauske and Associates, Inc. Reactive System Screening Tool tests, the onset or initiation temperature for a ferrocyanide-nitrate propagating reaction is about 250 degrees Celcius. This is at about 200 degrees Celcius higher than current waste temperatures in the highest temperature ferrocyanide tanks. Furthermore, for current ambient waste temperatures, the tube propagation tests show that a ferrocyanide concentration of 15.5 wt% or more is required to sustain a propagation reaction in the complete absence of free water. Ignoring the presence of free water, this finding rules out propagating reactions for all the Hanford flowsheet materials with the exception of the ferrocyanide waste produced by the original In Farm flowsheet

  14. Characterization of Hanford tank wastes containing ferrocyanides

    Tingey, J.M.; Matheson, J.D.; McKinley, S.G.; Jones, T.E.; Pool, K.H.

    1993-02-01

    Currently, 17 storage tanks on the Hanford site that are believed to contain > 1,000 gram moles (465 lbs) of ferrocyanide compounds have been identified. Seven other tanks are classified as ferrocyanide containing waste tanks, but contain less than 1,000 gram moles of ferrocyanide compounds. These seven tanks are still included as Hanford Watch List Tanks. These tanks have been declared an unreviewed safety question (USQ) because of potential thermal reactivity hazards associated with the ferrocyanide compounds and nitrate and nitrite. Hanford tanks with waste containing > 1,000 gram moles of ferrocyanide have been sampled. Extensive chemical, radiothermical, and physical characterization have been performed on these waste samples. The reactivity of these wastes were also studied using Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis. Actual tank waste samples were retrieved from tank 241-C-112 using a specially designed and equipped core-sampling truck. Only a small portion of the data obtained from this characterization effort will be reported in this paper. This report will deal primarily with the cyanide and carbon analyses, thermal analyses, and limited physical property measurements

  15. Cesium uptake capacity of simulated ferrocyanide tank waste. Interim report FY 1994, Ferrocyanide Safety Project

    Burgeson, I.E.; Bryan, S.A.; Burger, L.E.

    1994-09-01

    The objective of this project is to determine the capacity for 137 CS uptake by mixed metal ferrocyanides present in Hanford waste tanks, and to assess the potential for aggregation of these 137 CS exchanged materials to form tank ''hot-spots.'' This research, performed at the Pacific Northwest Laboratory (PNL) for the Westinghouse Hanford Company (WHC), stems from concerns of possible localized radiolytic heating within the tanks. If radioactive cesium is exchanged and concentrated by the remaining nickel ferrocyanide present in the tanks, this heating could cause temperatures to rise above the safety limits specified for the ferrocyanide tanks. For the purposes of this study, two simulants, In-Farm-2 and U-Plant-2, were chosen to represent the wastes generated by the scavenging processes. These simulants were formulated using protocols from the original cesium scavenging campaign. Later additions of cesium-rich wastes from various processes also were considered. The simulants were prepared and centrifuged to obtain a moist ferrocyanide sludge. The centrifuged sludges were treated with the original supernate spiked with a known amount of cesium nitrate. After analysis by flame atomic absorption spectrometry, distribution coefficients (K d ) were calculated. The capacity of solid waste simulants to exchange radioactive cesium from solution was examined. Initial results showed that the greater the molar ratio of cesium to cesium nickel ferrocyanide, the less effective the exchange of cesium from solution. The theoretical capacity of 2 mol cesium per mol of nickel ferrocyanide was not observed. The maximum capacity under experimental conditions was 0.35 mol cesium per mol nickel ferrocyanide. Future work on this project will examine the layering tendency of the cesium nickel ferrocyanide species

  16. Ferrocyanide safety program: Credibility of drying out ferrocyanide tank waste by hot spots

    Dickinson, D.R.; McLaren, J.M.; Borsheim, G.L.; Crippen, M.D.

    1993-04-01

    The single-shell waste tanks at the Hanford Site that contain significant quantities of ferrocyanide have been considered a possible hazard, since under certain conditions the ferrocyanide in the waste tanks could undergo an exothermic chemical reaction with the nitrates and nitrites that are also present in the tanks. The purpose of this report is to assess the credibility of local dryout of ferrocyanide due to a hotspot. This report considers the following: What amount of decay heat generation within what volume would be necessary to raise the temperature of the liquid in the sludge to its boiling point? What mechanisms could produce a significant local concentration of heat sources? Is it credible that a waste tank heat concentration could be as large as that required to reach the dryout temperatures? This report also provides a recommendation as to whether infrared scanning of the ferrocyanide tanks is needed. From the analyses presented in this report it is evident that formation of dry, and thus chemically reactive, regions in the ferrocyanide sludge by local hotspots is not credible. This conclusion is subject to reevaluation if future analyses of tank core samples show much higher 137 Cs or 90 Sr concentrations than expected. Since hotspots of concern are not credible, infrared scanning to detect such hotspots is not required for safe storage of tank waste

  17. Ferrocyanide Safety Program: Safety criteria for ferrocyanide watch list tanks

    Postma, A.K.; Meacham, J.E.; Barney, G.S.

    1994-01-01

    This report provides a technical basis for closing the ferrocyanide Unreviewed Safety Question (USQ) at the Hanford Site. Three work efforts were performed in developing this technical basis. The efforts described herein are: 1. The formulation of criteria for ranking the relative safety of waste in each ferrocyanide tank. 2. The current classification of tanks into safety categories by comparing available information on tank contents with the safety criteria; 3. The identification of additional information required to resolve the ferrocyanide safety issue

  18. Ferrocyanide safety project ferrocyanide aging studies. Final report

    Lilga, M.A.; Hallen, R.T.; Alderson, E.V.

    1996-06-01

    This final report gives the results of the work conducted by Pacific Northwest National Laboratory (PNNL) from FY 1992 to FY 1996 on the Ferrocyanide Aging Studies, part of the Ferrocyanide Safety Project. The Ferrocyanide Safety Project was initiated as a result of concern raised about the safe storage of ferrocyanide waste intermixed with oxidants, such as nitrate and nitrite salts, in Hanford Site single-shell tanks (SSTs). In the laboratory, such mixtures can be made to undergo uncontrolled or explosive reactions by heating dry reagents to over 200 degrees C. In 1987, an Environmental Impact Statement (EIS), published by the U.S. Department of Energy (DOE), Final Environmental Impact Statement, Disposal of Hanford Defense High-Level Transuranic and Tank Waste, Hanford Site, Richland, Washington, included an environmental impact analysis of potential explosions involving ferrocyanide-nitrate mixtures. The EIS postulated that an explosion could occur during mechanical retrieval of saltcake or sludge from a ferrocyanide waste tank, and concluded that this worst-case accident could create enough energy to release radioactive material to the atmosphere through ventilation openings, exposing persons offsite to a short-term radiation dose of approximately 200 mrem. Later, in a separate study (1990), the General Accounting Office postulated a worst-case accident of one to two orders of magnitude greater than that postulated in the DOE EIS. The uncertainties regarding the safety envelope of the Hanford Site ferrocyanide waste tanks led to the declaration of the Ferrocyanide Unreviewed Safety Question (USQ) in October 1990

  19. Ferrocyanide safety project: Comparison of actual and simulated ferrocyanide waste properties

    Scheele, R.D.

    1995-10-01

    In 1995, available subsegment samples of wastes taken from the Hanford Site underground radioactive waste storage tanks 241-C-112 (C-112) and 241-C-109 (C-109) were reanalyzed to determine the nickel concentrations in the samples and to determine whether the use of a nickel crucible in the analytical sample preparation biased the reported nickel concentrations reported by Simpson and coworkers and in the original report that this report supplements. The reanalysis strategy to determine nickel was to use a sodium peroxide flux in a zirconium crucible instead of the previously used potassium hydroxide flux in a nickel crucible. This supplemental report provides the results of the reanalyses and updates tables from the original report which reflect the new nickel analyses. Nickel is important with respect to management of the potentially reactive ferrocyanide wastes as it is one of the key defining characteristics of the solids that resulted from scavenging radiocesium using ferrocyanides. In Hanford Site wastes, few other processes introduced nickel into the wastes other than radiocobalt scavenging, which was often coupled with the ferrocyanide-scavenging process. Thus the presence of nickel in a waste provides strong evidence that the original waste was or contained ferrocyanide waste at one time. Given the potential import of nickel as a defining characteristic and marker for ferrocyanide wastes, the Pacific Northwest Laboratory's (PNL) Analytical Chemistry Laboratory (ACL) reanalyzed available samples from tanks C-112 and C-109 using inductively coupled argon plasma/atomic emission spectrometry (ICP/AES) and an alternative sample preparation method which precluded contamination of the analytical samples with nickel

  20. Radiolysis of ferrocyanide solutions studied by infrared spectroscopy

    Le Caer, S. [CEA/Saclay, DSM/DRECAM/SCM/URA 331 CNRS, F-91191Gif-sur-Yvette Cedex (France)]. E-mail: sophie.le-caer@cea.fr; Vigneron, G. [CEA/Saclay, DSM/DRECAM/SCM/URA 331 CNRS, F-91191Gif-sur-Yvette Cedex (France); Renault, J.P. [CEA/Saclay, DSM/DRECAM/SCM/URA 331 CNRS, F-91191Gif-sur-Yvette Cedex (France); Pommeret, S. [CEA/Saclay, DSM/DRECAM/SCM/URA 331 CNRS, F-91191Gif-sur-Yvette Cedex (France)

    2007-08-15

    The behavior of the neutral and basic aqueous ferrocyanide system under irradiation is investigated using the coupling of a LINAC with infrared spectroscopy. The comparison between the neutral and basic system evidences the formation of the hydroxopentacyanoferrate (III) ions and gives information on the reaction mechanisms. The pseudo-protective effect of the dissolved dioxygen on the ferrocyanide is explained via a mechanism implying the superoxide radical anion.

  1. Ferrocyanide Safety Project: Subtask 3.4, Aging Studies

    Lilga, M.A.; Lumetta, M.R.; Riemath, W.F.; Romine, R.A.; Schiefelbein, G.F.

    1992-11-01

    The Hanford Ferrocyanide Task Team is addressing issues involving ferrocyanide precipitates in single-shell waste storage tanks (SSTs), in particular the storage of waste in a safe manner. This Task Team, composed of researchers from Westinghouse Hanford Company (WHC), Pacific Northwest Laboratory (PNL), and outside consultants, was formed in response to the need for an updated analysis of safety questions about the Hanford ferrocyanide tanks. This annual report gives the results of the work conducted by PNL in FY 1992 on Subtask 3.4, Aging Studies, which is part of Task 3, Chemical Nature of Feffocyanide in Wastes. Subtask 3.4 deals with the aging behavior and solubilization of ferrocyanide tank waste sludges in a basic aqueous environment. Investigated were the effects of pH variation, ionic strength, salts present in SSTS, and gamma radiation on solubilization of vendor-prepared Na 2 NiFe(CN) 6

  2. Ferrocyanide safety project ferrocyanide aging studies FY 1995 annual report

    Lilga, M.A.; Alderson, E.V.; Hallen, R.T.

    1995-09-01

    This annual report gives the results of the work conducted by the Pacific Northwest Laboratory in FY 1995 on Task 3 of the Ferrocyanide Safety Project, Ferrocyanide Aging Studies. Aging refers to the dissolution and hydrolysis of simulated Hanford ferrocyanide waste in alkaline aqueous solutions by radiolytic and chemical means. The ferrocyanide simulant primarily used in these studies was dried In-Farm-1B, Rev. 7, prepared by Westinghouse Hanford Company to simulate the waste generated when the In-Farm flowsheet was used to remove radiocesium from waste supernates in single-shell tanks at the Hanford Site. In the In-Farm flowsheet, nickel ion and ferrocyanide anion were added to waste supernates to precipitate sodium nickel ferrocyanide, Na 2 NiFe(CN) 6 , and co-precipitate radiocesium. Once the radiocesium was removed, supernates were pumped from the tanks, and new wastes from cladding removal processes or from evaporators were added. These new wastes were typically highly caustic, having hydroxide ion concentrations of over 1 M and as high as 4 M. The Aging Studies task is investigating reactions this caustic waste may have had with the precipitated ferrocyanide waste in a radiation field. In previous Aging Studies research, Na 2 NiFe(CN) 6 in simulants was shown to dissolve in basic solutions, forming insoluble Ni(OH) 2 and soluble Na 4 Fe(CN) 6 . The influence on solubility of base strength, sodium ion concentration, anions, and temperature was previously investigated. The results may indicate that even ferrocyanide sludge that did not come into direct contact with highly basic wastes may also have aged significantly

  3. A summary of available information on ferrocyanide tank wastes

    Burger, L.L.; Strachan, D.M.; Reynolds, D.A.; Schulz, W.W.

    1991-10-01

    Ferrocyanide wastes were generated at the Hanford site during the mid to late 1950s to make more tank space available for the storage of high level nuclear waste. The ferrocyanide process was developed as a method of removing 137 Cs from existing waste solutions and from process solutions that resulted from the recovery of valuable uranium in waste tanks. During the coarse of the research associated with the ferrocyanide process, it was discovered that ferrocyanide materials when mixed with NaNO 3 and/or NaNO 2 exploded. This chemical reactivity became an issue in the 1980s when the safety associated with the storage of ferrocyanide wastes in Hanford tanks became prominent. These safety issues heightened in the late 1980s and led to the current scrutiny of the safety associated with these wastes and the current research and waste management programs. Over the past three years, numerous explosive test have been carried out using milligram quantities of cyanide compounds. These tests provide information on the nature of possible tank reactions. On heating a mixture of ferrocyanide and nitrate or nitrite, an explosive reaction normally begins at about 240 degrees C, but may occur well below 200 degrees C in the presence of catalysts or organic compounds that may act as initiators. The energy released is highly dependent on the course of the reaction. Three attempts to model hot spots in local areas of the tanks indicate a very low probability of having a hot spot large enough and hot enough to be of concern. The main purpose of this document is to inform the members of the Tank Waste Science Panel of the background and issues associated with the ferrocyanide wastes. Hopefully, this document fulfills similar needs outside of the framework of the Tank Waste Science Panel. 50 refs., 9 figs., 7 tabs

  4. Resolution of the Hanford site ferrocyanide safety issue

    Cash, R.J.; Lilga, M.A.; Babad, H.

    1997-01-01

    The Ferrocyanide Safety Issue at the Hanford Site was officially resolved in December 1996. This paper summarizes the key activities that led to final resolution of this safety hazard, a process that began in 1990 after it and other safety concerns were identified for the underground high-level waste storage tanks at the Hanford Site. At the time little was known about ferrocyanide-nitrate/nitrite reactions and their potential to cause offsite releases of radioactivity. The ferrocyanide hazard was a perceived problem, but it took six years of intense studies and analyses of tank samples to prove that the problem no longer exists. The issue revolved around the fact that ferrocyanide and nitrate mixtures can be made to explode violently if concentrated, dry, and heated to temperatures of at least 250 degrees C. The studies conducted over the last six years have shown that the combined effects of temperature, radiation, and pH during 40 or more years of storage have destroyed almost all of the ferrocyanide originally added to tanks. This was shown in laboratory experiments using simulant wastes and confirmed by actual samples taken from the ferrocyanide tanks. The tank waste sludges are now too dilute to support a sustained exothermic reaction, even if dried out and heated to high temperatures. 2 tabs., 18 refs

  5. Was Ferrocyanide a Prebiotic Reagent?

    Keefe, Anthony D.; Miller, Stanley L.

    1996-01-01

    Hydrogen cyanide is the starting material for a diverse array of prebiotic syntheses, including those of amino acids and purines. Hydrogen cyanide also reacts with ferrous ions to give ferrocyanide, and so it is possible that ferrocyanide was common in the early ocean. This can only be true if the hydrogen cyanide concentration was high enough and the rate of reaction of cyanide with ferrous ions was fast enough. We show experimentally that the rate of formation of ferrocyanide is rapid even at low concentrations of hydrogen cyanide in the pH range 6-8, and therefore an equilibrium calculation is valid. The equilibrium concentrations of ferrocyanide are calculated as a function of hydrogen cyanide concentration, pH and temperature. The steady state concentration of hydrogen cyanide depends on the rate of synthesis by electric discharges and ultraviolet light and the rate of hydrolysis, which depends on pH and temperature. Our conclusions show that ferrocyanide was a major species in the prebiotic ocean only at the highest production rates of hydrogen cyanide in a strongly reducing atmosphere and at temperatures of 0 C or less, although small amounts would have been present at lower hydrogen cyanide production rates. The prebiotic application of ferrocyanide as a source of hydrated electrons, as a photochemical replication process, and in semi-permeable membranes is discussed.

  6. Ferrocyanide-containing waste tanks: Ferrocyanide chemistry and reactivity

    Scheele, R.D.; Burger, L.L.; Tingey, J.M.; Bryan, S.A.; Borsheim, G.L.; Simpson, B.C.; Cash, R.J.; Cady, H.H.

    1991-09-01

    The complexing constant for hexacyano-iron complexes, both Fe(2) and Fe(3), are exceptionally large. The derived transition metal salts or double salts containing alkali metal ions are only slightly soluble. The various nickel compounds examined in this study, i.e., those predicted to have been formed in the Hanford waste scavenging program, are typical examples. In spite of their relative stability towards most reagents under ambient conditions, they are all thermodynamically unstable towards oxidation and react explosively with oxidants such as nitrate or nitrate salts when heated to temperatures in excess of 200 degree C. 42 refs., 5 figs., 3 tabs

  7. Progress in evaluating the hazard of ferrocyanide waste storage tanks

    Babad, Harry; Cash, Robert J.; Postma, Arlin

    1992-01-01

    There are 177 high-level waste tanks on the Hanford site. Twenty-four single-shell tanks are identified as potential safety issues. These tanks contain quantities of ferrocyanide, nitrate, and nitrite salts that potentially could explode under certain conditions. Efforts were initiated in September 1990 to determine the reactive properties of the ferrocyanide waste and to define the criteria necessary to ensure tank safety until mitigation or remediation actions, if required, could be implemented. This paper describes the results of recent chemical and physical studies on synthetic ferrocyanide waste mixtures. Data obtained from monitoring, tank behavior modeling, and research studies on waste have provided sufficient understanding of the tank behavior. The Waste Tank Safety Program is exploring whether the waste in many of the ferrocyanide tanks actually represents an unreviewed safety question. The General Accounting Office (GAO) in October 1990 suggested that ferrocyanide tank accident scenarios exceed the bounds of the Hanford Environmental Impact Statement. Using the same assumptions Westinghouse Hanford Company (WHC) staff confirmed the consistency of the GAO report calculations. The hypothetical accident scenario in the GAO report, and in the EIS, are based on several assumptions that may, or may not reflect actual tank conditions. The Ferrocyanide Stabilization Program at Westinghouse Hanford (summarized in this paper) will provide updated and new data using scientific research with synthetic wastes and characterization of actual tank samples. This new information will replace the assumptions on tank waste chemical and physical properties allowing an improved recalculation of current safety and future risk associated with these tanks. (author)

  8. Progress in evaluating the hazards of ferrocyanide waste storage tanks

    Babad, H.; Cash, R.; Postma, A.

    1992-03-01

    There are 177 high-level waste tanks on the Hanford site. Twenty-four single-shell tanks are identified as potential safety issues. These tanks contain quantities of ferrocyanide, nitrate, and nitrite salts that potentially could explode under certain conditions. Efforts were initiated in September 1990 to determine the reactive properties of the ferrocyanide waste and to define the criteria necessary to ensure tank safety until mitigation or remediation actions, if required, could be implemented. This paper describes the results of recent chemical and physical studies on synthetic ferrocyanide waste mixtures. Data obtained from monitoring, tank behavior modeling, and research studies on waste have provided sufficient understanding of the tank behavior. The Waste Tank Safety Program is exploring to determine whether the waste in many of the ferrocyanide tanks actually represents an unreviewed safety question. The General Accounting Office (GAO) in October 1990 (1) suggested that ferrocyanide-tanks accident scenarios exceed the bounds of the Hanford Environmental Impact Statement (2). Using the same assumptions Westinghouse Hanford Company (WHC) staff confirmed the consistency of the GAO report calculations. The hypothetical accident scenario in the GAO report, and in the EIS, are based on several assumptions that may, or may not reflect actual tank conditions. The Ferrocyanide Stabilization Program at Westinghouse Hanford (summarized in this paper) will provide updated and new data using scientific research with synthetic and actual waste tank characterization. This new information will replace the assumptions on tank waste chemical and physical properties allowing an improved recalculation of current safety and future risk associated with these tanks

  9. Resolution of the ferrocyanide safety issue for the Hanford site high-level waste tanks

    Cash, R.J.

    1996-01-01

    This paper describes the approach used to resolve the ferrocyanide safety issue, a process that began in 1990 after heightened concern was expressed by various government agencies about the safety of Hanford site high-level waste tanks. At the time, little was known about ferrocyanide-nitrate/nitrite reactions and the potential for offsite releases of radioactivity from the Hanford Site. Recent studies have shown that the combined effects of temperature, radiation, and pH during more than 38 years of storage have destroyed most of the ferrocyanide originally added to tanks. This has been proven in the laboratory using flowsheet-derived waste simulants and confirmed by waste samples obtained from the ferrocyanide tanks. The resulting tank waste sludges are too dilute to support a sustained exothermic reaction, even if dried out and heated to temperatures of at least 250 C. The US Department of Energy (DOE) has been requested to close the ferrocyanide safety issue

  10. Ferrocyanide safety program: An assessment of the possibility of ferrocyanide sludge dryout

    Epstein, M.; Fauske, H.K.; Dickinson, D.R.; Crippen, M.D.; McCormack, J.D.; Cash, R.J.; Meacham, J.E.; Simmons, C.S.

    1994-09-01

    Much attention has been focused on the Hanford Site radioactive waste storage tanks as a results of problems that have been envisioned for them. One problem is the potential chemical reaction between ferrocyanide precipitate particles and nitrates in the absence of water. This report addresses the question of whether dryout of a portion of ferrocyanide sludge would render it potentially reactive. Various sludge dryout mechanisms were examined to determine if any of them could occur. The mechanisms are: (1) bulk heating of the entire sludge inventory to its boiling point; (2) loss of liquid to the atmosphere via sludge surface evaporation; (3) local drying by boiling in a hot spot region; (4) sludge drainage through a leak in the tank wall; and (5) local drying by evaporation from a warm segment of surface sludge. From the simple analyses presented in this report and more detailed published analyses, it is evident that global loss of water from bulk heating of the sludge to its boiling point or from surface evaporation and vapor transport to the outside air is not credible. Also, from the analyses presented in this report and experimental and analytical work presented elsewhere, it is evident that formation of a dry local or global region of sludge as a result of tank leakage (draining of interstitial liquid) is not possible. Finally, and most importantly, it is concluded that formation of dry local regions in the ferrocyanide sludge by local hot spots or warm surface regions is not possible. The conclusion that local or global dryout is incredible is consistent with four decades of waste storage history, during which sludge temperature have gradually decreased or remained constant and the sludge moisture content has been retained. 54 refs

  11. Buoyancy Effect of Ionic Vacancy on the Change of the Partial Molar Volume in Ferricyanide-Ferrocyanide Redox Reaction under a Vertical Gravity Field

    Yoshinobu Oshikiri

    2013-01-01

    Full Text Available With a gravity electrode (GE in a vertical gravity field, the buoyancy effect of ionic vacancy on the change of the partial molar volume in the redox reaction between ferricyanide (FERRI and ferrocyanide (FERRO ions was examined. The buoyancy force of ionic vacancy takes a positive or negative value, depending on whether the rate-determining step is the production or extinction of the vacancy. Though the upward convection over an upward electrode in the FERRO ion oxidation suggests the contribution of the positive buoyancy force arising from the vacancy production, the partial molar volume of the vacancy was not measured. On the other hand, for the downward convection under a downward electrode in the FERRI ion reduction, it was not completely but partly measured by the contribution of the negative buoyancy force from the vacancy extinction. Since the lifetime of the vacancy is decreased by the collision between ionic vacancies during the convection, the former result was ascribed to the shortened lifetime due to the increasing collision efficiency in the enhanced upward convection over an upward electrode, whereas the latter was thought to arise from the elongated lifetime due to the decreasing collision efficiency by the stagnation under the downward electrode.

  12. Ferrocyanide tank safety program: Cesium uptake capacity of simulated ferrocyanide tank waste. Final report

    Burgeson, I.E.; Bryan, S.A.

    1995-07-01

    The objective of this project is to determine the capacity for 137 Cs uptake by mixed metal ferrocyanides present in Hanford Site waste tanks, and to assess the potential for aggregation of these 137 Cs-exchanged materials to form ''hot-spots'' in the tanks. This research, performed at Pacific Northwest Laboratory (PNL) for Westinghouse Hanford Company, stems from concerns regarding possible localized radiolytic heating within the tanks. After ferrocyanide was added to 18 high-level waste tanks in the 1950s, some of the ferrocyanide tanks received considerable quantities of saltcake waste that was rich in 137 Cs. If radioactive cesium was exchanged and concentrated by the nickel ferrocyanide present in the tanks, the associated heating could cause tank temperatures to rise above the safety limits specified for the ferrocyanide-containing tanks, especially if the supernate in the tanks is pumped out and the waste becomes drier

  13. Characterization and reaction behavior of ferrocyanide simulants and Hanford Site high-level ferrocyanide waste

    Jeppson, D.W.; Simpson, B.C.

    1994-02-01

    Nonradioactive waste simulants and initial ferrocyanide tank waste samples were characterized to assess potential safety concerns associated with ferrocyanide high-level radioactive waste stored at the Hanford Site in underground single-shell tanks (SSTs). Chemical, physical, thermodynamic, and reaction properties of the waste simulants were determined and compared to properties of initial samples of actual ferrocyanide wastes presently in the tanks. The simulants were shown to not support propagating reactions when subjected to a strong ignition source. The simulant with the greatest ferrocyanide concentration was shown to not support a propagating reaction that would involve surrounding waste because of its high water content. Evaluation of dried simulants indicated a concentration limit of about 14 wt% disodium mononickel ferrocyanide, below which propagating reactions could not occur in the ambient temperature bulk tank waste. For postulated localized hot spots where dried waste is postulated to be at an initial temperature of 130 C, a concentration limit of about 13 wt% disodium mononickel ferrocyanide was determined, below which propagating reactions could not occur. Analyses of initial samples of the presently stored ferrocyanide waste indicate that the waste tank ferrocyanide concentrations are considerably lower than the limit for propagation for dry waste and that the water content is near that of the as-prepared simulants. If the initial trend continues, it will be possible to show that runaway ferrocyanide reactions are not possible under present tank conditions. The lower ferrocyanide concentrations in actual tank waste may be due to tank waste mixing and/or degradation from radiolysis and/or hydrolysis, which may have occurred over approximately 35 years of storage

  14. Characterization report for the ferrocyanide safety issue

    Pulsipher, B.A.; Burger, L.L.; Liebetrau, A.M.; Scheele, R.D.

    1997-06-01

    Recently PNNL was tasked by DOE to develop and demonstrate a risk-based strategic approach to characterizing Hanford's Nuclear Waste Tanks. This strategic approach was documented in a report entitled ''A Risk-Based Focused Decision-Management Approach for Justifying Characterization of Hanford Tank Waste''. In support of the general approach, a specific strategy for addressing each of the several safety issues associated with the tanks was developed. This report documents the approach for the Ferrocyanide Safety Issue. The purpose of this report is to describe a structured logic diagram (SLD) for determining the risk associated with the ferrocyanide tank safety issue and provide the supporting information for the SLD. The SLD addresses the resolution of risks resulting from the presence of ferrocyanide layers within the Hanford tanks. The informational requirements for determining risk from any reaction stemming from ferrocyanide are outlined in the SLD. This report will describe the potential paths to a successful resolution of the ferrocyanide safety issue. Complete development of the intervention pathway is outside the scope of this current activity. General descriptions of the approach, key components of the SLD, and conclusions are provided in the body of this report. The complete SLD, descriptions of each box shown in the SLD, a discussion on how to fill data needs, and a list of contributors is provided in the appendices

  15. Scanning electron microscopic analyses of Ferrocyanide tank wastes for the Ferrocyanide safety program

    Callaway, W.S.

    1995-09-01

    This is Fiscal Year 1995 Annual Report on the progress of activities relating to the application of scanning electron microscopy in addressing the Ferrocyanide Safety Issue associated with Hanford Site high-level radioactive waste tanks. The status of the FY 1995 activities directed towards establishing facilities capable of providing SEM based micro-characterization of ferrocyanide tank wastes is described. A summary of key events in the SEM task over FY 1995 and target activities in FY 1996 are presented. A brief overview of the potential applications of computer controlled SEM analytical data in light of analyses of ferrocyanide simulants performed by an independent contractor is also presented

  16. Evaluation of ferrocyanide/nitrate explosive hazard

    Cady, H.H.

    1992-06-01

    Los Alamos National Laboratory agreed to assist Pacific Northwest Laboratory in the Ferrocyanide Safety Evaluation Program by helping to evaluate the explosive hazard of several mixtures of simulated ferrocyanide waste-tank sludge containing sodium nitrite and sodium nitrate. This report is an evaluation of the small-scale safety tests used to assess the safety of these materials from an explosive point of view. These tests show that these materials are not initiated by mechanical insult, and they require an external heat source before any exothermic chemical reaction can be observed

  17. Resolving the Ferrocyanide Safety Issue at the Hanford Site

    Meacham, J.E.; Cash, R.J.; Babad, H.

    1994-02-01

    Considerable data have been obtained on the chemical and physical properties of ferrocyanide waste stored in Hanford Site single-shell tanks (SSTs). Theoretical analyses and ferrocyanide waste simulant studies have led to the development of fuel, moisture, and temperature criteria that define continued safe storage. Developing the criteria provides the technical basis for closing the Ferrocyanide Unreviewed Safety Question (USQ). Using the safety criteria, the ferrocyanide tanks have been ranked into one of three safety categories: Safe, Conditionally Safe, and Unsafe. All the ferrocyanide tanks are currently ranked in either the Safe or Conditionally Safe categories. Analyses of core samples taken from three ferrocyanide tanks have shown cyanide concentrations about a factor of ten lower than predicted by the original flowsheets. Hydrolytic and radiolytic destruction (aging) of the ferrocyanide matrix has occurred during the 35 plus years the waste has been stored at the Hanford Site. Because of waste aging, it is possible that all of the ferrocyanide tanks may now contain less than the 8 wt % sodium nickel ferrocyanide specified in the fuel criterion for the Safe category. Ferrocyanide tanks that remain in the Conditionally Safe category may require monitoring and surveillance to verify that the waste remains in an unreactive state. Further characterization of the tanks by core sampling and analyses should lead to resolution of the Ferrocyanide Safety Issue by September 1997

  18. Preparation methods of copper-ferrocyanide functionalized magnetic nanoparticles for selective removal of cesium in aqueous solution

    Hee-Man Yang; Kune Woo Lee; Bum-Kyoung Seo; Jei Kwon Moon [KAERI, Daejeon (Korea, Republic of)

    2013-07-01

    Copper ferrocyanide functionalized magnetite nanoparticles (Cu-FC-MNPs) were successfully synthesized by the immobilization of copper and ferrocyanide on the surface of [1-(2 amino-ethyl)-3-aminopropyl] trimethoxysilane modified magnetite nanoparticles. A radioactive cesium (Cs) adsorption test was carried out to investigate the effectiveness of Cu-FC-MNPS for the removal of radioactive Cs. Furthermore, the Cu-FC-MNPs showed excellent separation ability by an external magnet in an aqueous solution. (authors)

  19. Study of the Szilard-Chalmers effect on potassium ferrocyanide; Etude de l'effet Szilard-Chalmers sur le ferrocyanure de potassium

    Henry, R; Aubertin, C; Valade, J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    Irradiation conditions and a simple chemical treatment are described, for obtaining from potassium ferrocyanide the mixture {sup 55}Fe, {sup 59}Fe with a high specific activity. The recoil behaviour of the two isotopes is shown to be different: because of its greater energy {sup 55}Fe will be enriched by extraction of the ejected atoms from the rest of the molecule. An attempt is made to explain the increase in retention as proportional to the decrease in specific activity. (author) [French] Les conditions d'irradiation du ferrocyanure de potassium et un traitement chimique simple sont donnes pour permettre l'obtention du melange {sup 55}Fe, {sup 59}Fe de grande activite specifique. On a mis en evidence une difference de comportement des deux isotopes sous l'effet de recul; l'energie plus grande du {sup 55}Fe permettant son enrichissement par extraction des atomes ejectes du reste de la molecule. Un essai d'explication de l'augmentation de la retention proportionnellement a la diminution de l'activite specifique est donne. (auteur)

  20. Ferrocyanide safety project task 3 ferrocyanide aging studies FY 1994 annual report

    Lilga, M.A.; Alderson, E.V.; Kowalski, D.J.; Lumetta, M.R.; Schiefelbein, G.F.

    1994-09-01

    The research performed for this project is part of an effort begun in the mid-1980s to characterize the materials stored in the single-shell waste storage tanks (SSTs) at the U.S. Department of Energy (DOE) Hanford Site. Various radioactive wastes from defense operations have accumulated at the Hanford Site in underground waste tanks since the early 1940s. The goal of the Aging Studies task is to understand the long-term chemical and radiolytic behavior of ferrocyanide tank wastes in the SST environments. In turn, this information provides baseline data that will be useful as actual SST samples are obtained and analyzed. The results of aging studies will directly assist in determining which strategy will assure safe storage of the ferrocyanide waste in the tanks and how the ferrocyanide safety issue can be resolved. This report contains the results of FY 1994 research for the Aging Studies task, which focused on the hydrolysis of ferrocyanide waste simulants in aqueous base. Hydrolysis was investigated in 2M NaOH as a function of temperature, applied gamma dose rate, and soluble Fe(CN) 6 -4 concentration. A hydrolysis experiment was conducted at pH 10 and another in the presence of aluminum. In addition, experiments investigating cesium ion exchange in competition with sodium nickel ferrocyanide dissolution were conducted

  1. Photoconductivity studies of the ferrocyanide ion under high pressure

    Finston, M. I.

    1979-01-01

    The photoaquation of the ferrocyanide ion was studied using a high-pressure photoconductivity apparatus and a steady-state high-pressure mercury lamp. The first-order photocurrent rise-time could be related to the relative quantum efficiency of the photoaquation process, while the dark decay of the photocurrent yielded a relative value of the bimolecular rate-constant for the reverse reaction. Kinetic measurements were carried out on dilute solutions of potassium ferrocyanide in pure water, and in 20% ethanol. The photocurrent yield in aqueous solution was dependent upon secondary chemical equilibria which were sensitive to pressure in a predictable way. In ethanolic solution, the dependence of photocurrent yield on pressure followed the variation of the reciprocal solvent vicosity. In both aqueous and alcoholic solution, the photoaquation quantum efficiency decreased exponentially with pressure, as did the biomolecular rate-constant for the dark reaction in aqueous solution. The pressure dependence of the bimolecular rate-constant in the alcoholic solution indicated a diffusion-limited process. The pressure dependence of the photoaquation quantum yield, and of the bimolecular rate-constant in aqueous solution, was interpreted in terms of an activation volume model. The photoaquation data for both the aqueous and the alcoholic solutions agreed with a hypothetical mechanism whereby ligand-to-metal bond-breaking, and solvent-to-metal bond-formation, are effectively simultaneous. The results for the aqueous dark reaction strongly indicated breaking of the solvent-to-metal bond as the rate-limiting step.

  2. The role of aging in resolving the ferrocyanide safety issue

    Babad, H.; Meacham, J.E.; Simpson, B.C.; Cash, R.J.

    1993-08-01

    A chemical process called aging, in which stored ferrocyanide waste could be dissolved and dispersed among waste tanks, or destroyed by radiolysis and hydrolysis, has been proposed at the Hanford Site. This paper summarizes the results of applied research, characterization, and modeling activities on Hanford Site ferrocyanide waste material that support the existence of a chemical aging mechanism. Test results from waste simulants and actual waste tank materials are presented and compared with theoretical estimates. Chemical and energetic behavior of the materials are the key indicators of destruction or dispersion. Screening experiments on vendor-prepared sodium nickel ferrocyanide and the initial results from core sampling support the concept that aging of ferrocyanide is taking place in the waste tanks at the Hanford Site. This report defines the concept of waste aging and explains the role that aging could play in resolving the Hanford Site ferrocyanide safety issue

  3. Adsorption of 137Cs on titanium ferrocyanide and transformation of the sorbent to lithium titanate. A new method for long term immobilization of 137Cs

    Barbara Bartos; Barbara Filipowicz; Monika Lyczko; Aleksander Bilewicz

    2014-01-01

    Dynamic adsorption of radiocesium on titanium ferrocyanide grains from reactor coolant simulating solution containing salts at moderate concentrations has been investigated. Effective decontamination of the neutral solutions has been achieved, in the amounts of a more than 20 thousand bed volumes. After adsorption the titanium ferrocyanide was transferred to titanates and calcined at 900 deg C. The leaching test of the obtained lithium titanates indicates that the loaded adsorbent can serve as an effective primary barrier in nuclear waste repositories. (author)

  4. Adsorption of 137Cs on titanium ferrocyanide and transformation of the sorbent to lithium titanate: a new method for long term immobilization of 137Cs.

    Bartoś, Barbara; Filipowicz, Barbara; Łyczko, Monika; Bilewicz, Aleksander

    Dynamic adsorption of radiocesium on titanium ferrocyanide grains from reactor coolant simulating solution containing salts at moderate concentrations has been investigated. Effective decontamination of the neutral solutions has been achieved, in the amounts of a more than 20 thousand bed volumes. After adsorption the titanium ferrocyanide was transferred to titanates and calcined at 900 °C. The leaching test of the obtained lithium titanates indicates that the loaded adsorbent can serve as an effective primary barrier in nuclear waste repositories.

  5. Colloid stable sorbents for cesium removal: Preparation and application of latex particles functionalized with transition metals ferrocyanides

    Avramenko, Valentin [Institute of Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159 ave 100-letiya Vladivostoka, Vladivostok 690022 (Russian Federation); Bratskaya, Svetlana, E-mail: sbratska@ich.dvo.ru [Institute of Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159 ave 100-letiya Vladivostoka, Vladivostok 690022 (Russian Federation); Zheleznov, Veniamin; Sheveleva, Irina [Institute of Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159 ave 100-letiya Vladivostoka, Vladivostok 690022 (Russian Federation); Voitenko, Oleg [Far Eastern Federal University, Laboratory of Electron Microscopy and Image Processing, 27, Oktyabr' skaya Street, Vladivostok 690950 (Russian Federation); Sergienko, Valentin [Institute of Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159 ave 100-letiya Vladivostoka, Vladivostok 690022 (Russian Federation)

    2011-02-28

    In this paper we suggest a principally new approach to preparation of colloid stable selective sorbents for cesium uptake using immobilization of transition metals (cobalt, nickel, and copper) ferrocyanides in nanosized carboxylic latex emulsions. The effects of ferrocyanide composition, pH, and media salinity on the sorption properties of the colloid stable sorbents toward cesium ions were studied in solutions containing up to 200 g/L of sodium nitrate or potassium chloride. The sorption capacities of the colloid sorbents based on mixed potassium/transition metals ferrocyanides were in the range 1.3-1.5 mol Cs/mol ferrocyanide with the highest value found for the copper ferrocyanide. It was shown that the obtained colloid-stable sorbents were capable to penetrate through bulk materials without filtration that made them applicable for decontamination of solids, e.g. soils, zeolites, spent ion-exchange resins contaminated with cesium radionuclides. After decontamination of liquid or solid radioactive wastes the colloid-stable sorbents can be easily separated from solutions by precipitation with cationic flocculants providing localization of radionuclides in a small volume of the precipitates formed.

  6. Ferrocyanide Safety Project: Comparison of actual and simulated ferrocyanide waste properties

    Scheele, R.D.; Burger, L.L.; Sell, R.L.; Bredt, P.R.; Barrington, R.J.

    1994-09-01

    In the 1950s, additional high-level radioactive waste storage capacity was needed to accommodate the wastes that would result from the production of recovery of additional nuclear defense materials. To provide this additional waste storage capacity, the Hanford Site operating contractor developed a process to decontaminate aqueous wastes by precipitating radiocesium as an alkali nickel ferrocyanide; this process allowed disposal of the aqueous waste. The radiocesium scavenging process as developed was used to decontaminate (1) first-cycle bismuth phosphate (BiPO 4 ) wastes, (2) acidic wastes resulting from uranium recovery operations, and (3) the supernate from neutralized uranium recovery wastes. The radiocesium scavenging process was often coupled with other scavenging processes to remove radiostrontium and radiocobalt. Because all defense materials recovery processes used nitric acid solutions, all of the wastes contained nitrate, which is a strong oxidizer. The variety of wastes treated, and the occasional coupling of radiostrontium and radiocobalt scavenging processes with the radiocesium scavenging process, resulted in ferrocyanide-bearing wastes having many different compositions. In this report, we compare selected physical, chemical, and radiochemical properties measured for Tanks C-109 and C-112 wastes and selected physical and chemical properties of simulated ferrocyanide wastes to assess the representativeness of stimulants prepared by WHC

  7. Contribution to the study of the Szilard-Chalmers effect in potassium ferro-cyanide; Contribution a l'etude de l'effet Szilard-Chalmers dans le ferrocyanure de potassium

    Meriadec, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-01-01

    With a view to studying the Szilard-Chalmers effect in potassium ferrocyanide, a chemical separation method has been developed for the different ions formed by recoil: Fe{sup 2+}, Fe{sup 3+} and the complex forms of iron. A measurement method has been developed also for analyzing separately the isotopes {sup 55}Fe and {sup 59}Fe, and determining the relative amounts of these two isotopes in the different chemical states. The experimental results show that the activity of the two isotopes is distributed differently between the complex forms of iron, the ferrous ions and the ferric ions. This difference is of the order of 40 per cent in the ferrous solution and of 2 to 5 per cent in the ferric retention and ferric solution. (author) [French] En vue d'etudier l'effet Szilard-Chalmers dans le ferrocyanure de potassium, on a mis au point une methode de separation chimique permettant d'obtenir les differents ions formes par recul: Fe{sup 2+}, Fe{sup 3+} et les formes complexes du fer. Une methode de mesure a ete egalement mise au point pour analyser separement les isotopes {sup 55}Fe et {sup 59}Fe et determiner les proportions relatives de ces 2 isotopes dans les differents etats chimiques. Les resultats experimentaux montrent que l'activite des deux isotopes est repartie differemment entre les formes complexes du fer, les ions ferreux et les ions ferriques. Cette difference est de l'ordre de 40 pour cent dans la solution ferreuse et de 2 a 5 pour cent dans la retention et la solution ferrique. (auteur)

  8. Energetics and kinetics of ferrocyanide and nitrate/nitrite reactions

    Scheele, R.D.; Burger, L.L.; Sell, R.L.

    1994-01-01

    During the 1950's, radiocesium scavenging at the Hanford site resulted in radioactive waste sludges containing ferrocyanide, nitrate, and nitrite. These waters are a concern since certain mixtures of ferrocyanide and nitrate and/or nitrite are known to explode when heated. The authors have used differential scanning calorimetry, thermogravimetric analysis, isothermal calorimetry and gravimetry, and accelerating rate calorimetry to measure the thermal behavior, the reaction enthalpies, and selected kinetic parameters for reactions between sodium nickel ferrocyanide, the suspected ferrocyanide form in Hanford wastes, and nitrate and/or nitrite. These studies indicate that the oxidation proceeds via multiple steps, the initial reaction begins near 200 degrees C, the initial step has a high activation energy (>200 kJ/mole-K), succeeding reaction steps have activation energies ranging from 90 to 160 kJ/mole-K, and that the oxidation yields about 50% of the theoretical heat of reaction for the most energetic reaction

  9. Possible use of ferrocyanide as a redox additive for prevention of electrolyte decomposition in overcharged nickel batteries

    Xiaoming Zhu [Wuhan University (China). Dept. of Chemistry; College of Xianning (China). Dept. of Chemistry; Hanxi Yang; Xingping Ai [Wuhan University (China). Dept. of Chemistry

    2003-11-30

    The redox reaction of ferrocyanide was investigated for possible use as a redox additive for the prevention of the electrolyte decomposition of aqueous secondary Ni-NH batteries in the overcharged condition. It was found that with the presence of ferrocyanide, the charging voltage can be leveled off just above the complete oxidation of the positive nickel electrode. As a result, the oxygen evolution was greatly suppressed and the internal pressure of the batteries was kept at low level even at prolonged overcharging. In addition, no detrimental effects of the redox additive were observed on the normal charge-discharge performance of Ni-MH batteries. (author)

  10. Conversion of radioactive ferrocyanide compounds to immobile glasses

    Schulz, W.W.; Dressen, A.L.

    1977-01-01

    Complex radioactive ferrocyanide compounds result from the scavenging of cesium from waste products produced in the chemical reprocessing of nuclear fuel. These ferrocyanides, in accordance with this process, are converted to an immobile glass, resistant to leaching by water, by fusion together with sodium carbonate and a mixture of (a) basalt and boron trioxide (B 2 O 3 ) or (b) silica (SiO 2 ) and lime (CaO). 7 claims

  11. Ferrocyanide Safety Program cyanide speciation studies. Final report

    Bryan, S.A.; Pool, K.H.; Bryan, S.L.

    1995-07-01

    This report summarizes Pacific Northwest Laboratory's fiscal year (FY) 1995 progress toward developing and implementing methods to identify and quantify cyanide species in ferrocyanide tank waste. This work was conducted for Westinghouse Hanfbrd Company's (WHC's) Ferrocyanide Safety Program. Currently, there are 18 high-level waste storage tanks at the US Department of Energy's Hanford Site that are on a Ferrocyanide Tank Watchlist because they contain an estimated 1000 g-moles or more of precipitated ferrocyanide. In the presence of oxidizing material such as sodium nitrate or nitrite, ferrocyanide can be made to react exothermally by heating it to high temperatures or by applying an electrical spark of sufficient energy (Cady 1993). However, fuel, oxidizers, and temperature are all important parameters. If fuel, oxidizers, or high temperatures (initiators) are not present in sufficient amounts, then a runaway or propagating reaction cannot occur. To bound the safety concern, methods are needed to definitively measure and quantitate ferrocyanide concentration present within the actual waste. The target analyte concentration for cyanide in waste is approximately 0.1 to 15 wt % (as cyanide) in the original undiluted sample. After dissolution of the original sample and appropriate dilutions, the concentration range of interest in the analytical solutions can vary between 0.001 to 0.1 wt % (as cyanide). In FY 1992, 1993, and 1994, two solution (wet) methods were developed based on Fourier transform infrared (FTIR) spectroscopy and ion chromatography (IC); these methods were chosen for further development activities. The results of these activities are described

  12. Contribution to the study of recoil species produced by potassium ferrocyanide neutron irradiation

    Meriadec Vernier de Byans, B.

    1969-04-01

    The chemical species produced by potassium ferrocyanide neutron irradiation were separated and identified. The study of their behaviour upon thermal annealing has allowed to establish a scheme of reaction as well as a kinetic treatment of the data. Activation energies are determined in different conditions and the effects of radiation dose, oxygen and water of crystallisation upon the activation energies were studied. Preliminary E.S.R. data and its relevance to the decomposition process is also discussed. (authors) [fr

  13. Ferrocyanide safety program cyanide speciation studies FY 1993 annual report

    Bryan, S.A.; Pool, K.H.; Bryan, S.L.; Sell, R.L.; Thomas, L.M.P.

    1993-09-01

    This report summarizes Pacific Northwest Laboratory's (PNL) FY 1993 progress toward developing and implementing methods to identify and quantify cyanide species in ferrocyanide tank waste. Currently, there are 24 high-level waste storage tanks at the US Department of Energy's (DOE) Hanford Site that have been placed on a Ferrocyanide Tank Watchlist because they contain an estimated 1000 g-moles or more of precipitated ferrocyanide. This amount of ferrocyanide is of concern because the consequences of a potential explosion may exceed those reported previously in safety analyses. To bound the safety concern, methods are needed to definitively measure and quantitate the amount of ferrocyanides present within actual waste tanks to a lower limit of at least 0.1 wt % up to approximately 15 wt %. The target analyte concentration for cyanide in waste is approximately 0.1 to 15 wt % (as CN) in the original undiluted sample. After dissolution of the original sample and appropriate dilutions, the concentration range of interest in the analytical solutions can vary between 0.001 to 0.1 wt % (as CN)

  14. The nature of chemical bonding in actinide and lanthanide ferrocyanides determined by X-ray absorption spectroscopy and density functional theory.

    Dumas, Thomas; Guillaumont, Dominique; Fillaux, Clara; Scheinost, Andreas; Moisy, Philippe; Petit, Sébastien; Shuh, David K; Tyliszczak, Tolek; Den Auwer, Christophe

    2016-01-28

    The electronic properties of actinide cations are of fundamental interest to describe intramolecular interactions and chemical bonding in the context of nuclear waste reprocessing or direct storage. The 5f and 6d orbitals are the first partially or totally vacant states in these elements, and the nature of the actinide ligand bonds is related to their ability to overlap with ligand orbitals. Because of its chemical and orbital selectivities, X-ray absorption spectroscopy (XAS) is an effective probe of actinide species frontier orbitals and for understanding actinide cation reactivity toward chelating ligands. The soft X-ray probes of the light elements provide better resolution than actinide L3-edges to obtain electronic information from the ligand. Thus coupling simulations to experimental soft X-ray spectral measurements and complementary quantum chemical calculations yields quantitative information on chemical bonding. In this study, soft X-ray XAS at the K-edges of C and N, and the L2,3-edges of Fe was used to investigate the electronic structures of the well-known ferrocyanide complexes K4Fe(II)(CN)6, thorium hexacyanoferrate Th(IV)Fe(II)(CN)6, and neodymium hexacyanoferrate KNd(III)Fe(II)(CN)6. The soft X-ray spectra were simulated based on quantum chemical calculations. Our results highlight the orbital overlapping effects and atomic effective charges in the Fe(II)(CN)6 building block. In addition to providing a detailed description of the electronic structure of the ferrocyanide complex (K4Fe(II)(CN)6), the results strongly contribute to confirming the actinide 5f and 6d orbital oddity in comparison to lanthanide 4f and 5d.

  15. Solubility of ferrocyanide compounds. Ferrocyanide Safety Project, Interim report FY1994

    Rai, D.; Felmy, A.R.; Smith, S.C.; Ryan, J.L.

    1994-10-01

    The solubility of Cs 2 NiFe(CN) 6 (c) [1] as a function of NaOH and temperature was determined to ascertain whether [1] shows retrograde solubility (i.e., decreasing solubility with increasing temperature), which would have bearing on the possible formation of ''hot spots'' in the tanks and thus the safety of the ferrocyanide tanks. The results show that the aqueous concentrations of Cs in equilibrium with [1] at 25, 60, 75 and 90 C are similar (within the limits of experimental error), indicating that [1] does not show retrograde solubility. To understand general solubility relationships of Ni 2 Fe(CN) 6 (c) [2] and to determine the influence on solubility of high electrolyte concentrations (e.g., NaNO 3 ) that are commonly encountered in the ferrocyanide tanks, the solubility of [2] as a function of CsNO 3 , NiCl 2 , and NaNO 3 was determined. In general, [2] is fairly insoluble and shows slightly increased solubility at high electrolyte concentrations only. For [2] in NiCl 2 , the aqueous Fe concentrations show first a decrease and then an increase with the increase in NiCl 2 concentrations. The increase in Fe concentrations at high Ni concentrations appears to be the result of replacement of Fe by Ni in the [2] structure. For [2] in CsNO 3 and at 0.001 M Na 4 Fe(CN) 6 , the Cs is quantitatively removed from solution at low added Cs concentrations and appears to approach the final solid composition of [1]. The solubility of [2] in NaNO 3 and at 0.001 M Na 4 Fe(CN) 6 shows an increase in Ni concentrations to about 0.5 mg/l at NaNO 3 concentrations > 1.0 M. These increased Ni concentrations may be the result of substitution of Na for Ni in the solid phase

  16. Ferrocyanide Safety Program: Data requirements for the ferrocyanide safety issue developed through the data quality objectives (DQO) process

    Buck, J.W.; Anderson, C.M.; Pulsipher, B.A.; Toth, J.J.; Turner, P.J.; Cash, R.J.; Dukelow, G.T.; Meacham, J.E.

    1993-12-01

    This document records the data quality objectives (DQO) process applied to the Ferrocyanide Waste Tank Safety Issue at the Hanford Site by the Pacific Northwest Laboratory and Westinghouse Hanford Company. Specifically, the major recommendations and findings from this Ferrocyanide DQO process are presented so that decision makers can determine the type, quantity, and quality of data required for addressing tank safety issues. The decision logic diagrams and error tolerance equations also are provided. Finally, the document includes the DQO sample-size formulas for determining specific tank sampling requirements

  17. Computational analysis of coupled fluid, heat, and mass transport in ferrocyanide single-shell tanks: FY 1994 interim report. Ferrocyanide Tank Safety Project

    McGrail, B.P.

    1994-11-01

    A computer modeling study was conducted to determine whether natural convection processes in single-shell tanks containing ferrocyanide wastes could generate localized precipitation zones that significantly concentrate the major heat-generating radionuclide, 137 Cs. A computer code was developed that simulates coupled fluid, heat, and single-species mass transport on a regular, orthogonal finite-difference grid. The analysis showed that development of a ''hot spot'' is critically dependent on the temperature dependence for the solubility of Cs 2 NiFe(CN) 6 or CsNaNiFe(CN) 6 . For the normal case, where solubility increases with increasing temperature, the net effect of fluid flow, heat, and mass transport is to disperse any local zones of high heat generation rate. As a result, hot spots cannot physically develop for this case. However, assuming a retrograde solubility dependence, the simulations indicate the formation of localized deposition zones that concentrate the 137 Cs near the bottom center of the tank where the temperatures are highest. Recent experimental studies suggest that Cs 2 NiFe(CN) 6 (c) does not exhibit retrograde solubility over the temperature range 25 degree C to 90 degree C and NaOH concentrations to 5 M. Assuming these preliminary results are confirmed, no natural mass transport process exists for generating a hot spot in the ferrocyanide single-shell tanks

  18. Ferrocyanide Safety Program: Waste tank sludge rheology within a hot spot or during draining

    Fauske, H.K.; Cash, R.J.

    1993-11-01

    The conditions under which ferrocyanide waste sludge flows as a homogeneous non-Newtonian two-phase (solid precipitate-liquid) mixture rather than as a liquid through a porous medium (of stationary precipitate) are examined theoretically, based on the notion that the preferred rheological behavior of the sludge is the one which imposes the least resistance to the sludge flow. The homogeneous two-phase mixture is modeled as a power-law fluid and simple criteria are derived that show that the homogeneous power-law sludge-flow is a much more likely flow situation than the porous medium model of sludge flow. The implication of this finding is that the formation of a hot spot or the drainage of sludge from a waste tank are not likely to result in the uncovering (drying) and subsequent potential overheating of the reactive-solid component of the sludge

  19. Intra- and inter-atomic optical transitions of Fe, Co, and Ni ferrocyanides studied using first-principles many-electron calculations

    Watanabe, Shinta, E-mail: s-watanabe@nucl.nagoya-u.ac.jp, E-mail: j-onoe@nucl.nagoya-u.ac.jp; Sawada, Yuki; Nakaya, Masato; Yoshino, Masahito; Nagasaki, Takanori; Onoe, Jun, E-mail: s-watanabe@nucl.nagoya-u.ac.jp, E-mail: j-onoe@nucl.nagoya-u.ac.jp [Department of Materials, Physics and Energy Engineering, Graduated School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Kameyama, Tatsuya; Torimoto, Tsukasa [Department of Crystalline Materials Science, Graduated School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Inaba, Yusuke; Takahashi, Hideharu; Takeshita, Kenji [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1-N1-16 O-okayama, Meguro-ku, Tokyo 152-8550 (Japan)

    2016-06-21

    We have investigated the electronic structures and optical properties of Fe, Co, and Ni ferrocyanide nanoparticles using first-principles relativistic many-electron calculations. The overall features of the theoretical absorption spectra for Fe, Ni, and Co ferrocyanides calculated using a first-principles many-electron method well reproduced the experimental one. The origins of the experimental absorption spectra were clarified by performing a configuration analysis based on the many-electron wave functions. For Fe ferrocyanide, the experimental absorption peaks originated from not only the charge-transfer transitions from Fe{sup 2+} to Fe{sup 3+} but also the 3d-3d intra-transitions of Fe{sup 3+} ions. In addition, the spin crossover transition of Fe{sup 3+} predicted by the many-electron calculations was about 0.24 eV. For Co ferrocyanide, the experimental absorption peaks were mainly attributed to the 3d-3d intra-transitions of Fe{sup 2+} ions. In contrast to the Fe and Co ferrocyanides, Ni ferrocyanide showed that the absorption peaks originated from the 3d-3d intra-transitions of Ni{sup 3+} ions in a low-energy region, while from both the 3d-3d intra-transitions of Fe{sup 2+} ions and the charge-transfer transitions from Fe{sup 2+} to Ni{sup 3+} in a high-energy region. These results were quite different from those of density-functional theory (DFT) calculations. The discrepancy between the results of DFT calculations and those of many-electron calculations suggested that the intra- and inter-atomic transitions of transition metal ions are significantly affected by the many-body effects of strongly correlated 3d electrons.

  20. Ferrocyanide safety project: Task 3.5 cyanide species analytical methods development

    Bryan, S.A.; Pool, K.H.; Burger, L.L.; Carlson, C.D.; Hess, N.J.; Matheson, J.D.; Ryan, J.L.; Scheele, R.D.; Tingey, J.M.

    1993-01-01

    This report summarizes the results of studies conducted in FY 1992 to develop methods for the identification and quantification of cyanide species in ferrocyanide tank waste. Currently there are 24 high-level waste storage tanks at the Hanford Site that have been placed on a Ferrocyanide Tank Watchlist because they contain an estimated 1,000 g-moles or greater amount of precipitated ferrocyanide. This amount of ferrocyanide is of concern because the consequences of a potential explosion may exceed those reported previously in safety analyses. The threshold concentration of total cyanide within the tank waste matrix that is expected to be a safety concern is estimated at approximately 1 to 3 wt%. Methods for detection and speciation of ferrocyanide complexes in actual waste are needed to definitively measure and quantitate the amount of ferrocyanides present within actual waste tanks to a lower limit of at least 0.1 wt% in order to bound the safety concern

  1. Assessment of the potential for ferrocyanide propagating reaction accidents

    Meacham, J.E.; Cash, R.J.; Dickinson, D.R.

    1996-01-01

    This report contains safety criteria for the storage of ferrocyanide bearing waste sludges in Hanford underground waste storage tanks. In addition, the tank wastes are categorized with this criteria into SAFE, CONDITIONALLY SAFE, and UNSAFE categories based on available historical records and sample information. Fourteen (14) tanks are classified as CONDITIONALLY SAFE, while four (4) C-Farm tanks are categorized as SAFE. This report therefore provides a technical basis to resolve the ferrocyanide safety issue for these four tanks and supports their removal from the Watch List. The 14 CONDITIONALLY SAFE tanks will be re-evaluated in a future revision to this report as representative sample data becomes available. It is anticipated that the 14 tanks will be re-categorized as SAFE at that time

  2. Redox properties of the nitronyl nitroxide antioxidants studied via their reactions with nitroxyl and ferrocyanide.

    Bobko, A A; Khramtsov, V V

    2015-01-01

    Nitronyl nitroxides (NNs) are the paramagnetic probes that are capable of scavenging physiologically relevant reactive oxygen (ROS) and nitrogen (RNS) species, namely superoxide, nitric oxide (NO), and nitroxyl (HNO). NNs are increasingly considered as potent antioxidants and potential therapeutic agents. Understanding redox chemistry of the NNs is important for their use as antioxidants and as paramagnetic probes for discriminative detection of NO and HNO by electron paramagnetic resonance (EPR) spectroscopy. Here we investigated the redox properties of the two most commonly used NNs, including determination of the equilibrium and rate constants of their reduction by HNO and ferrocyanide, and reduction potential of the couple NN/hydroxylamine of nitronyl nitroxide (hNN). The rate constants of the reaction of the NNs with HNO were found to be equal to (1-2) × 10(4) M(-1)s(- 1) being close to the rate constants of scavenging superoxide and NO by NNs. The reduction potential of the NNs and iminonitroxides (INs, product of NNs reaction with NO) were calculated based on their reaction constants with ferrocyanide. The obtained values of the reduction potential for NN/hNN (E'0 ≈ 285 mV) and IN/hIN (E' ≈ 495 mV) are close to the corresponding values for vitamin C and vitamin E, correspondingly. The "balanced" scavenging rates of the NNs towards superoxide, NO, and HNO, and their low reduction potential being thermodynamically close to the bottom of the pecking order of oxidizing radicals, might be important factors contributing into their antioxidant activity.

  3. Reactivity analysis of core distortion effects in the FFTF

    Knutson, B.J.

    1982-01-01

    An improved technique for evaluating core distortion reactivity effects was developed using reactivity analyses of two core geometry models (R-Z and HEX). This technique is incorporated into a new processor code called CORDIS. The advantages of this technique over existing reactivity models are that is preserves core heterogeneity, provides a control rod insertion effect model, uses row-dependent axial shape functions, and provides a flexible and cost efficient core distortion reactivity analysis method

  4. Reactivity effects due to beryllium poisoning of BR2

    Kalcheva, S.; Ponsard, B.; Koonen, E.

    2004-01-01

    This paper illustrates the impact of the poisoning of the beryllium reflector on reactivity variations of the Belgian MTR BR2 in SCK.CEN. Detailed calculations by MCNP-4C of reactivity effects caused by strong neutron absorbers 3 He and 6 Li during reactor operation history are presented. The importance of beryllium poisoning for the accuracy of reactivity predictions is discussed. (authors)

  5. Synthesis and characterization of cobalt ferrocyanides loaded on organic anion exchanger

    Valsala, T.P. [Waste Management Division, Bhabha Atomic Research Centre, Trombay 400 085 (India)], E-mail: tpvalsala@yahoo.co.in; Joseph, Annie [Waste Management Division, Bhabha Atomic Research Centre, Trombay 400 085 (India); Shah, J.G. [Back End Technology Division, Bhabha Atomic Research Centre, Trombay 400 085 (India); Raj, Kanwar [Waste Management Division, Bhabha Atomic Research Centre, Trombay 400 085 (India); Venugopal, V. [Radiochemistry and Isotope Group, Bhabha Atomic Research Centre, Trombay 400 085 (India)

    2009-02-15

    Transition metal ferrocyanides have important applications in the selective removal of radioactive caesium from low level and intermediate level radioactive liquid waste streams. The microcrystalline nature of these materials renders them useless for application in column mode operations. Special preparation procedures have been developed to prepare granular solids by in situ precipitation of metal ferrocyanides on organic anion exchangers, which is suitable for column mode operations. The elemental compositions of the metal ferrocyanides precipitated inside the pores of anion exchanger were determined by analysing the dissolved samples using ICP-AES system and flame photometer. From the XRD and EDX analyses and the elemental composition of the synthesized materials, the nature of the compound formed inside the anion exchanger was found to be cobalt ferrocyanide. From SEM analysis of the samples, the particle size of the cobalt ferrocyanide precipitated inside the anion exchanger was found to be much less than that of cobalt ferrocyanide precipitated outside. The efficiency of these materials for removal of Cs was evaluated by measuring the distribution coefficient (Kd), ion exchange capacity and kinetics of Cs uptake. The Kd of the materials loaded on anion exchanger was found to be of the order of 10{sup 5} ml/g. The Cs uptake kinetics of the materials loaded on anion exchanger was slower than that of precipitated materials. The ion exchange capacity of the cobalt ferrocyanide loaded on anion exchanger was found to be much higher than that of the precipitated cobalt ferrocyanide.

  6. Program plan for evaluation of the Ferrocyanide Waste Tank safety issue at the Hanford Site

    Borsheim, G.L.; Meacham, J.E.; Cash, R.J.; Dukelow, G.T.

    1994-03-01

    This document describes the background, priorities, strategy and logic, and task descriptions for the Ferrocyanide Waste Tank Safety Program. The Ferrocyanide Safety Program was established in 1990 to provide resolution of a major safety issue identified for 24 high-level radioactive waste tanks at the Hanford Site

  7. Development of Stable Solidification Method for Insoluble Ferrocyanides-13170

    Ikarashi, Yuki; Masud, Rana Syed; Mimura, Hitoshi [Dept. of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University, Aramaki-Aza-Aoba6-6-01-2, Sendai, 980-8579 (Japan); Ishizaki, Eiji; Matsukura, Minoru [UNION SHOWA K.K. 17-20, Mita 2-chome, Minato-ku, Tokyo 108-0073 (Japan)

    2013-07-01

    The development of stable solidification method of insoluble ferrocyanides sludge is an important subject for the safety decontamination in Fukushima NPP-1. By using the excellent immobilizing properties of zeolites such as gas trapping ability and self-sintering properties, the stable solidification of insoluble ferrocyanides was accomplished. The immobilization ratio of Cs for K{sub 2}[CoFe(CN){sub 6}].nH{sub 2}O saturated with Cs{sup +} ions (Cs{sub 2}[CoFe(CN){sub 6}].nH{sub 2}O) was estimated to be less than 0.1% above 1,000 deg. C; the adsorbed Cs{sup +} ions are completely volatilized. In contrast, the novel stable solid form was produced by the press-sintering of the mixture of Cs{sub 2}[CoFe(CN){sub 6}].nH{sub 2}O and zeolites at higher temperature of 1,000 deg. C and 1,100 deg. C; Cs volatilization and cyanide release were completely depressed. The immobilization ratio of Cs, under the mixing conditions of Cs{sub 2}[CoFe(CN){sub 6}].nH{sub 2}O:CP= 1:1 and calcining temperature: 1,000 deg. C, was estimated to be nearly 100%. As for the kinds of zeolites, natural mordenite (NM), clinoptilolite (CP) and Chabazite tended to have higher immobilization ratio compared to zeolite A. This may be due to the difference in the phase transformation between natural zeolites and synthetic zeolite A. In the case of the composites (K{sub 2-X}Ni{sub X/2}[NiFe(CN){sub 6}].nH{sub 2}O loaded natural mordenite), relatively high immobilization ratio of Cs was also obtained. This method using zeolite matrices can be applied to the stable solidification of the solid wastes of insoluble ferrocyanides sludge. (authors)

  8. Ion exchange of alkaline metals on the thin-layer zinc ferrocyanide

    Betenekov, N.D.; Buklanov, G.V.; Ipatova, E.G.; Korotkin, Yu.S.

    1991-01-01

    Basic regularities of interphase distribution in the system of thin-layer sorbent on the basis of mixed zinc ferrocyanide (FZ)-alkaline metal solution (Na, K, Rb, Cs, Fr) in the column chromatography made are studied. It is established that interphase distribution of microgram amounts of alkaline metals in the systems thin-layer FZ-NH 4 NO 3 electrolyte solutions is of ion-exchange character and subjected to of law effective mass. It is shown that FZ thin-layer material is applicable for effective chromatographic separation of alkaline metal trace amounts. An approach to the choice of a conditions of separate elution of Na, K, Rb, Cs, Fr in the column chromatography mode

  9. Effect of 137Cs on immunological reactivity

    Shubik, V.M.

    1975-01-01

    An important role of 137 Cs as a new ecological factor was shown by analyzing 31 different studies. The radioisotope may at present be detected in the organisms of all inhabitants of this planet. The migration of 137 Cs along the chain lichen-deer-man leads to its accumulation in the organism of humans living in the Extreme North and taking venison in their food. Although the high sensitivity of immunological reactions to various unfavourable environmental factors is well known, data on the effect of incorporated 137 Cs on immunity are scanty. Experiments on animals showed changes in factors of nonspecific immunity (phagocytic reaction of blood neutrophils, bactericidal activity, lysozyme and complement titres of blood serum) and specific immunity (formation of antiviral antibodies). The blood of animals injured by the isotope displays complete and incomplete autoantibodies. The dependence of immunobiological changes on the dose absorbed by the organism is shown. The 137 Cs intake of inhabitants of the Extreme North who eat venison did not, with the absorbed dose equalling up to 50 Mrem per year, lead to changes in their immunological reactivity. (author)

  10. Chitosan-ferrocyanide sorbent for Cs-137 removal from mineralized alkaline media

    Egorin, Andrei [Far Eastern Federal Univ., Vladivostok (Russian Federation); Institute of Chemistry FEBRAS, Vladivostok (Russian Federation); Ozyorsk Technical Institute MEPHI, Ozersk (Russian Federation); Tokar, Eduard [Far Eastern Federal Univ., Vladivostok (Russian Federation); Zemskova, Larisa [Institute of Chemistry FEBRAS, Vladivostok (Russian Federation)

    2016-11-01

    An organomineral sorbent based on mixed nickel-potassium ferrocyanide and chitosan to be used in removal of Cs-137 radionuclide from highly mineralized media with high pH has been fabricated. The synthesized sorbent was applied to remove Cs-137 from model solutions under static and dynamic conditions. The effects of contact time, pH, and presence of sodium ions and complexing agents in the process of Cs-137 removal have been investigated. The sorbent is distinguished by increased stability to the impact of alkaline media containing complexing agents, whereas the sorbent capacity in solutions with pH 11 exceeds 1000 bed volumes with the Cs-137 removal efficiency higher than 95%.

  11. Actinide and Xenon reactivity effects in ATW high flux systems

    Woosley, M.; Olson, K.; Henderson, D.L.

    1995-01-01

    In this paper, initial system reactivity response to flux changes caused by the actinides and xenon are investigated separately for a high flux ATW system. The maximum change in reactivity after a flux change due to the effect of the changing quantities of actinides is generally at least two orders of magnitude smaller than either the positive or negative reactivity effect associated with xenon after a shutdown or start-up. In any transient flux event, the reactivity response of the system to xenon will generally occlude the response due to the actinides

  12. Actinide and xenon reactivity effects in ATW high flux systems

    Woosley, M.; Olson, K.; Henderson, D. L.; Sailor, W. C.

    1995-01-01

    In this paper, initial system reactivity response to flux changes caused by the actinides and xenon are investigated separately for a high flux ATW system. The maximum change in reactivity after a flux change due to the effect of the changing quantities of actinides is generally at least two orders of magnitude smaller than either the positive or negative reactivity effect associated with xenon after a shutdown or start-up. In any transient flux event, the reactivity response of the system to xenon will generally occlude the response due to the actinides

  13. Actinide and Xenon reactivity effects in ATW high flux systems

    Woosley, M. [Univ. of Virginia, Charlottesville, VA (United States); Olson, K.; Henderson, D.L. [Univ. of Wisconsin, Madison, WI (United States)] [and others

    1995-10-01

    In this paper, initial system reactivity response to flux changes caused by the actinides and xenon are investigated separately for a high flux ATW system. The maximum change in reactivity after a flux change due to the effect of the changing quantities of actinides is generally at least two orders of magnitude smaller than either the positive or negative reactivity effect associated with xenon after a shutdown or start-up. In any transient flux event, the reactivity response of the system to xenon will generally occlude the response due to the actinides.

  14. Data requirements for the Ferrocyanide Safety Issue developed through the data quality objectives process

    Meacham, J.E.; Cash, R.J.; Dukelow, G.T.; Babad, H.; Buck, J.W.; Anderson, C.M.; Pulsipher, B.A.; Toth, J.J.; Turner, P.J.

    1994-08-01

    This document records the data quality objectives (DQO) process applied to the Ferrocyanide Safety Issue at the Hanford Site. Specifically, the major recommendations and findings from this Ferrocyanide DQO process are presented. The decision logic diagrams and decision error tolerances also are provided. The document includes the DQO sample-size formulas for determining specific tank sampling requirements, and many of the justifications for decision thresholds and decision error tolerances are briefly described. More detailed descriptions are presented in other Ferrocyanide Safety Program companion documents referenced in this report. This is a living document, and the assumptions contained within will be refined as more data from sampling and characterization become available

  15. Effect of substituents on the reactivity of ninhydrin with urea

    Jong, Jacobus A.W.; Moret, Marc Etienne; Verhaar, Marianne C.; Hennink, Wim E.; Gerritsen, Karin G.F.; Van Nostrum, Cornelus F.

    2018-01-01

    Ninhydrin, i. e. the stable hydrate of the reactive species indanetrione, is a well-known compound used for the quantification of ammonia and amino acids. However, substituent effects on the reactivity of ninhydrin with nucleophiles are not described. In this work, the kinetics of the reaction of

  16. Ferrocyanide Safety Program rationale for removing six tanks from the safety watch list

    Borsheim, G.L.

    1993-09-01

    This report documents an in-depth study of single-shell tanks containing ferrocyanide wastes. Topics include: safety assessments, tank histories, supportive documentation about interim stabilization and planned remedial activities

  17. Moisture monitoring of ferrocyanide tanks: An evaluation of methods and tools

    Meacham, J.E.; Babad, H.; Toffer, H.

    1993-04-01

    This report reviews the strengths and limitations of moisture monitoring technologies that could be used for determining moisture concentration in Hanford Site single-shell ferrocyanide waste tanks. Two technologies (neutron diffusion and near-infrared spectroscopy) are being pursued as part of the ferrocyanide program. A third technology, Raman spectroscopy, is in development as a speciation tool at the Westinghouse Hanford Company 222-S Laboratory. The potential application of Raman spectroscopy to moisture monitoring is discussed

  18. Measurement of reactivity effect caused by nonuniform fuel distribution

    Yamane, Yoshihiro; Hirano, Yasushi; Yasui, Hazime; Nishina, Kojiro; Shiroya, Seiji

    1991-01-01

    A reactivity effect due to a spatial variation of nuclear fuel concentration is an important problem in a reprocessing plant. To estimate this reactivity effect theoretically, the ''Goertzel's necessary condition, and th Fuel Importance'' theory have been proposed. In order to verify these theories, we have performed systematic measurements of reactivity effect due to the nonuniformity in the fuel distribution within the Kyoto University Critical Assembly. Neutron flux distribution and Fuel Importance distribution were also determined. A nonuniform assembly whose fuel concentration in the center region was 40% higher than the uniform one was found to have an excess reactivity of 0.3%Δk/k, with the same total uranium mass for which the uniform assembly was just critical. Moreover, its spatial distribution of thermal neutron flux and of Fuel Importance were more flat than those of the uniform assembly, as expected by the Goertzel's condition and the Fuel Importance theory. (Author)

  19. Argon plasma treatment to enhance the electrochemical reactivity of screen-printed carbon surfaces

    Ghamouss, F.; Luais, E. [Universite de Nantes, Faculte des Sciences et des Techniques, Chimie et Interdisciplinarite: Synthese, Analyse, Modelisation (CEISAM), UMR CNRS no 6230, 2, rue de la Houssiniere, BP 92208, 44322 NANTES Cedex 3 (France); Universite de Nantes, Institut des Materiaux Jean Rouxel IMN - CNRS, 2 rue de la Houssiniere, BP 32229, 44322 Nantes Cedex 3 (France); Thobie-Gautier, C. [Universite de Nantes, Faculte des Sciences et des Techniques, Chimie et Interdisciplinarite: Synthese, Analyse, Modelisation (CEISAM), UMR CNRS no 6230, 2, rue de la Houssiniere, BP 92208, 44322 NANTES Cedex 3 (France); Tessier, P.-Y. [Universite de Nantes, Faculte des Sciences et des Techniques, Chimie et Interdisciplinarite: Synthese, Analyse, Modelisation (CEISAM), UMR CNRS no 6230, 2, rue de la Houssiniere, BP 92208, 44322 NANTES Cedex 3 (France); Universite de Nantes, Institut des Materiaux Jean Rouxel IMN - CNRS, 2 rue de la Houssiniere, BP 32229, 44322 Nantes Cedex 3 (France); Boujtita, M. [Universite de Nantes, Faculte des Sciences et des Techniques, Chimie et Interdisciplinarite: Synthese, Analyse, Modelisation (CEISAM), UMR CNRS no 6230, 2, rue de la Houssiniere, BP 92208, 44322 NANTES Cedex 3 (France)], E-mail: mohammed.boujtita@univ-nantes.fr

    2009-04-15

    Radiofrequency argon plasma was used for screen-printed carbon electrodes (SPCE) surface treatment. The cyclic voltammetry of ferri/ferrocyanide as redox couple showed a remarkable improvement of the electrochemical reactivity of the SPCE after the plasma treatment. The effect of the plasma growth conditions on the efficiency of the treatment procedure was evaluated in term of electrochemical reactivity of the SPCE surface. The electrochemical study showed that the electrochemical reactivity of the treated electrodes was strongly dependant on radiofrequency power, treatment time and argon gas pressure. X-ray photoelectron spectroscopy (XPS) analysis showed a considerable evolution on the surface chemistry of the treated electrodes. Our results clearly showed that the argon plasma treatment induces a significant increase in the C{sub sp2}/C{sub sp3} ratio. The scanning electron micrograph (SEM) also showed a drastic change on the surface morphology of the treated SPCEs.

  20. First-principles modeling of metal (ii) ferrocyanide: electronic property, magnetism, bulk moduli, and the role of C  ≡  N− defect

    Le, Hung M; Pham, Tan-Tien; Dat, Vo Duy; Kawazoe, Yoshiyuki

    2017-01-01

    The ferrocyanide structures of transition metals (M) Ti 2+ , Cr 2+ , Mn 2+ , or Co 2+ are investigated using a first-principles modeling approach. The crystal structure of cobalt ferrocyanide is found to resemble previous experimental data with good accuracy (∼1% error). The considered porous structures possess magnetic moments of 8.00 µ B /cell, 8.00 µ B /cell, 4.00 µ B /cell, and 4.00 µ B /cell given by the [TiFe(CN) 6 ] 2− , [CrFe(CN) 6 ] 2− , [MnFe(CN) 6 ] 2− , and [CoFe(CN) 6 ] 2− frameworks, respectively. There is only one spin-state occupation at the Fermi level, which leads to the conclusion of semi-metallicity of the four structures. To verify the reliability of the electronic and magnetic properties, linear-response DFT  +   U calculations are performed and establish excellent agreement with the conventional DFT calculations. Then, the mechanical strength is evaluated by estimating the bulk moduli of the four structures, which fall in the range of 114 GPa–133 GPa. Upon the consideration of one C  ≡  N − linker defect, the magnetic moments of cobalt ferrocyanide and manganese ferrocyanide rise dramatically to 8 µ B /cell, while that of the titanium structure drops to 6 µ B /cell. In light of the electronic structure evidence, we believe that the low-spin Fe cation nearby the C  ≡  N − defect has an indirect effect on spin polarization of the four Co cations in the unit cell. (paper)

  1. Synthesis of Iron-ferrocyanide functionalized magnetic nanocluster for the removal of cesium

    Yang, Hee-Man; Jang, Sung-Chan; Lee, Kune Woo; Seo, Bum-Kyoung; Moon, Jei Kwon

    2014-01-01

    In the present study, magnetite nanocluster was synthesized by hydrothermal method, and coated with iron ferrocyanide for the adsorption of cesium in an aqueous solution through simple addition of iron ferrocyanide in acid condition. We describe the morphology, structure, and physical property of these nanoparticles. In addition, their ability to eliminate cesium from water was also evaluated. In this study, we fabricated Iron ferrocyanide immobilized magnetite nanocluster (IFC-MNC) using hydrothermal methods. The CIFC-MNC exhibited easy separation ability from water by an external magnet, and showed a high removal efficiency of cesium in aqueous solutions. Therefore, the IFC-MNC demonstrated good potential for the treatment of water contaminated with radioactive cesium. gnetic nanoadsorbents composed of a magnetic particles core and functional shell, which adsorb the contaminants, has attracted significant attention in environmental remediation owing to their high surface area and unique superparamagnetism. The nuclear accident at the Fukushima Daiichi nuclear power station in 2011 released a huge quantity of radioactive contaminants into the environment. Among these, cesium Cs-137 is the most problematic contaminant due to its long half-life (30.2 years), and high-energy gamma ray (γ-ray) emissions. Among various adsorbents to treat Cs-137 contaminated water, metal ferrocyanides were widely applied to remove the Cs-137 in water. For better separation of metal ferrocyanide from water, recently, our group reported the fabrication of copper ferrocyanide-functionalized magnetic nanoparticles (Cu-FC-EDA-MNPs) using alkoxysilanes, having ethylenediamine (EDA) group, modified Fe 3 O 4 nanoparticles (EDA-MNPs) for the fast and easy magnetic separation of metal ferrocyanide. However, the fabrication method was multistep procedure. Thus, a more simplified fabrication procedure is still desired

  2. Synthesis of Iron-ferrocyanide functionalized magnetic nanocluster for the removal of cesium

    Yang, Hee-Man; Jang, Sung-Chan; Lee, Kune Woo; Seo, Bum-Kyoung; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    In the present study, magnetite nanocluster was synthesized by hydrothermal method, and coated with iron ferrocyanide for the adsorption of cesium in an aqueous solution through simple addition of iron ferrocyanide in acid condition. We describe the morphology, structure, and physical property of these nanoparticles. In addition, their ability to eliminate cesium from water was also evaluated. In this study, we fabricated Iron ferrocyanide immobilized magnetite nanocluster (IFC-MNC) using hydrothermal methods. The CIFC-MNC exhibited easy separation ability from water by an external magnet, and showed a high removal efficiency of cesium in aqueous solutions. Therefore, the IFC-MNC demonstrated good potential for the treatment of water contaminated with radioactive cesium. gnetic nanoadsorbents composed of a magnetic particles core and functional shell, which adsorb the contaminants, has attracted significant attention in environmental remediation owing to their high surface area and unique superparamagnetism. The nuclear accident at the Fukushima Daiichi nuclear power station in 2011 released a huge quantity of radioactive contaminants into the environment. Among these, cesium Cs-137 is the most problematic contaminant due to its long half-life (30.2 years), and high-energy gamma ray (γ-ray) emissions. Among various adsorbents to treat Cs-137 contaminated water, metal ferrocyanides were widely applied to remove the Cs-137 in water. For better separation of metal ferrocyanide from water, recently, our group reported the fabrication of copper ferrocyanide-functionalized magnetic nanoparticles (Cu-FC-EDA-MNPs) using alkoxysilanes, having ethylenediamine (EDA) group, modified Fe{sub 3}O{sub 4} nanoparticles (EDA-MNPs) for the fast and easy magnetic separation of metal ferrocyanide. However, the fabrication method was multistep procedure. Thus, a more simplified fabrication procedure is still desired.

  3. Effect of reactive feedback on the transverse mode coupling instability

    Myers, S.

    1984-08-01

    An important and realistic test to examine the effect of reactive feedback on the transverse mode coupling instability could be performed at PEP using the existing feedback system with some minor modifications. This test would of necessity take place at low energy and low synchrotron tune. Such an experiment is of great importance for the design of the LEP reactive feedback system and for the ultimate evaluation of LEP performance

  4. Destruction of nitrates, organics, and ferrocyanides by hydrothermal processing

    Robinson, J.M.; Foy, B.R.; Dell'Orco, P.C.; Anderson, G.; Archuleta, F.; Atencio, J.; Breshears, D.; Brewer, R.; Eaton, H.; McFarland, R.; McInroy, R.; Reynolds, T.; Sedillo, M.; Wilmanns, E.; Buelow, S.J.

    1993-01-01

    This work targets the remediation of the aqueous mixed wastes stored in the underground tanks at the Department of Energy site in Hanford, Washington via hydrothermal processing. The feasibility of destroying the nitrate, organic, and ferrocyanide components of the wastes under supercritical and near critical conditions (623 degree K to 873 degree K, 22.1 MPa to 103.4 MPa) is addressed. A novel method was developed for determining the solubility of nitrate salts in supercritical water solutions at pressures ranging from 24.8 MPa to 30.3 MPa (3600 psi to 4400 psi) and temperatures from 723 degree K to 798 degree K. Sodium nitrate solubilities ranged from 293 mg/kg at 24.8 MPa and 798 degree K to 1963 mg/kg at 30.3 MPa and 723 degree K. Solubility was found to vary directly with pressure, and inversely with temperature. An empirical relationship was developed for the estimation of sodium nitrate solubility at water densities between 0.08 and 0.16 kg/L and temperatures between 723 degree K and 798 degree K. A small volume batch reactor equipped with optical diagnostics was used to monitor the phase behavior of a diluted variant of a tank 101-SY simulant. Preliminary results suggest that a single phase is formed at 83 MPa at 773 degree K

  5. Ferrocyanide Safety Program: Data interpretation report for tank 241-T-107 core samples

    Sasaki, L.M.; Valenzuela, B.D.

    1994-08-01

    Between November 1992 and March 1993, three core samples were obtained from tank 241-T-107. Analyses were performed on these core samples to support the Ferrocyanide Safety Program and the Hanford Federal Facility Agreement and Consent Order (Ecology et al. 1994) Milestone M-10-00. This document summarizes and evaluates those analytical results that are pertinent to the Ferrocyanide Safety Issue. This document compares the analytical results with the data requirements for ferrocyanide tanks as documented in Data Requirements of the Ferrocyanide Safety Issue Developed Through the Data Quality Objectives Process (Meacham et al. 1994) and provides an assessment of the safety condition of the tank. Analytes not listed in the Data Quality Objectives (DQO) document (Meacham et al. 1994) or not pertinent to the Ferrocyanide Safety Issue are not discussed in this report. Complete documentation of the analytical results can be found in the data package for the tank 241-T-107 cores (Svancara and Pool 1993). A more complete evaluation of the analytical results and an estimate of the tank inventory will be provided in a forthcoming tank characterization report for tank 241-T-107

  6. Ferrocyanide Safety Project Dynamic X-Ray Diffraction studies of sodium nickel ferrocyanide reactions with equimolar nitrate/nitrite salts

    Dodds, J.N.; UNOCAL, Brea, CA

    1994-07-01

    Dynamic X-ray Diffraction (DXRD) has been to used to identify and quantify the solid state reactions that take place between sodium nickel ferrocyanide, Na 2 NiFe(CN) 6 , and equimolar concentrations of sodium nitrate/nitrite, reactions of interest to the continued environmental safety of several large underground waste storage tanks at the Hanford site in eastern Washington. The results are supportive of previous work, which indicated that endothermic dehydration and melting of the nitrates take place before the occurrence of exothermic reactions that being about 300 degrees C. The DXRD results show that a major reaction set at these temperatures is the occurrence of a series reaction that produces sodium cyanate, NaCNO, as an intermediate in a mildly exothermic first step. In the presence of gaseous oxygen, NaCNO subsequently reacts exothermally and at a faster rate to form metal oxides. Measurements of the rate of this reaction are used to estimate the heat release. Comparisons of this estimated heat release rate with heat transfer rates from a hypothetical ''hot spot'' show that, even in a worst-case scenario, the heat transfer rates are approximately eight times higher than the rate of energy release from the exothermic reactions

  7. Reactivity-flooding effect of the MNSR inner irradiation sites

    Khamis, I.; Khattab, K.

    1999-01-01

    For the purpose of safety assessments, evaluation of the reactivity effects of inner irradiation sites, being flooded with water in the MNSR reactor was conducted both numerically and experimentally. Measured and calculated effect of different combination of inner irradiation sites being flooded with water was evaluated numerically and experimentally. Good agreement between measurement and calculated results were obtained

  8. Quarterly report on the Ferrocyanide Safety Program for the period ending, March 31, 1995

    Cash, R.J.; Meacham, J.E.; Dukelow, G.T.

    1995-04-01

    This quarterly report provides a status of the activities underway on the Ferrocyanide Safety Issue at the Hanford Site, including actions in response to Defense Nuclear Facilities Safety Board (DNFSB) Recommendation 90-7 (FR 1990). In March 1991, a DNFSB implementation plan (Cash 1991) responding to the six parts of Recommendation 90-7 was prepared and sent to the DNFSB. A Ferrocyanide Safety Program Plan addressing the total Ferrocyanide Safety Program, including the six parts of DNFSB Recommendation 90-7, was released in October 1994 (DOE 1994b). Activities in the program plan are underway or have been completed, and the status of each is described in Sections 2.0 and 3.0 of this report

  9. Ferrocyanide safety program: FY 1995 report on Mossbauer spectroscopy tank activities

    Riedel, F.R.

    1995-01-01

    This report summarizes FY 1995 activities on the Mossbauer Spectroscopy task. The National Aeronautics and Space Administration has developed a miniaturized Mossbauer spectrometer that is small enough to perform elevation scans in the Hanford Site waste tank liquid observation wells. Mossbauer spectroscopy is a sensitive and selective method that can detect and distinguish between different iron-based compounds in many types of chemical environments. Iron is major constituent of ferrocyanide waste and information about its location and composition in the tanks supports interim safe storage of the waste and final resolution of the Ferrocyanide Safety Issue. Results obtained from studies of ferrocyanide waste simulants and those from the first test in a hot cell environment using radioactive tank waste are presented

  10. Void effects on BWR Doppler and void reactivity feedback

    Hsiang-Shou Cheng; Diamond, D.J.

    1978-01-01

    The significance of steam voids and control rods on the Doppler feedback in a gadolinia shimmed BWR is demonstrated. The importance of bypass voids when determining void feedback is also shown. Calculations were done using a point model, i.e., feedback was expressed in terms of reactivity coefficients which were determined for individual four-bundle configurations and then appropriately combined to yield reactor results. For overpower transients the inclusion of the void effect of control rods is to reduce Doppler feedback. For overpressurization transients the inclusion of the effect of bypass void wil increase the reactivity due to void collapse. (author)

  11. Spectral fine structure effects on material and doppler reactivity worth

    Greenspan, E.; Karni, Y.

    1975-01-01

    New formulations concerning the fine structure effects on the reactivity worth of resonances are developed and conclusions are derived following the extension to more general types of perturbations which include: the removal of resonance material at finite temperatures and the temperature variation of part of the resonance material. It is concluded that the flux method can overpredict the reactivity worth of resonance materials more than anticipated. Calculations on the Doppler worth were carried out; the results can be useful for asessing the contribution of the fine structure effects to the large discrepancy that exists between the calculated and measured small sample Doppler worths. (B.G.)

  12. Quarterly report on the Ferrocyanide Safety Program for the period ending June 30, 1995

    Meacham, J.E.; Cash, R.J.; Dukelow, G.T.

    1995-07-01

    This is the seventeenth quarterly report on the progress of activities addressing the Ferrocyanide Safety Issue associated with Hanford Site high-level radioactive waste tanks. Progress in the Ferrocyanide Safety Program is reviewed, including work addressing the six pans of Defense Nuclear Facilities Safety Board Recommendation 90-7 (FR 1990). All work activities are described in the revised program plan (DOE 1994b), and this report follows the same format presented there. A summary of the key events occurring this quarter is presented

  13. Quarterly report on the ferrocyanide safety program for the period ending December 31, 1994

    Meacham, J.E.; Cash, R.J.; Dukelow, G.T.

    1995-01-01

    This is the fifteenth quarterly report on the progress of active addressing the Ferrocyanide Safety Issue associated with Hanford Site high-level radioactive waste tanks. Progress in the Ferrocyanide Safety Program is reviewed, including work addressing the six parts of Defense Nuclear Facilities Safety Board Recommendation 90-7 (FR 1990). All work activities are described in the revised program plan (DOE 1994b), and this report follows the same format presented there. A summary of the key events occurring this quarter is presented in Section 1.2. More detailed discussions of progress are located in Sections 2.0 through 4.0. 60 refs

  14. Quarterly report on the Ferrocyanide Safety Program for the period ending September 30, 1995

    Meacham, J.E.; Cash, R.J.; Dukelow, G.T.

    1995-10-01

    This is the eighteenth quarterly report on the progress of activities addressing the Ferrocyanide Safety Issue associated with Hanford Site high-level radioactive waste tanks. Progress in the Ferrocyanide Safety Program is reviewed, including work addressing the six parts of Defense Nuclear Facilities Safety Board Recommendation 90-7 (FR 1990). All work activities are described in the revised program plan (DOE 1994b), and this report follows the same format presented there. A summary of the key events occurring this quarter is presented in Section 1.2. More detailed discussions of progress are located in Sections 2.0 through 4.0

  15. Effects of ouabain on vascular reactivity

    Vassallo D.V.

    1997-04-01

    Full Text Available Ouabain is an endogenous substance occurring in the plasma in the nanomolar range, that has been proposed to increase vascular resistance and induce hypertension. This substance acts on the a-subunit of Na+,K+-ATPase inhibiting the Na+-pump activity. In the vascular smooth muscle this effect leads to intracellular Na+ accumulation that reduces the activity of the Na+/Ca2+ exchanger and to an increased vascular tone. It was also suggested that circulating ouabain, even in the nanomolar range, sensitizes the vascular smooth muscle to vasopressor substances. We tested the latter hypothesis by studying the effects of ouabain in the micromolar and nanomolar range on phenylephrine (PE-evoked pressor responses. The experiments were performed in normotensive and hypertensive rats in vivo, under anesthesia, and in perfused rat tail vascular beds. The results showed that ouabain pretreatment increased the vasopressor responses to PE in vitro and in vivo. This sensitization after ouabain treatment was also observed in hypertensive animals which presented an enhanced vasopressor response to PE in comparison to normotensive animals. It is suggested that ouabain at nanomolar concentrations can sensitize vascular smooth muscle to vasopressor stimuli possibly contributing to increased tone in hypertension

  16. Effects of age on reactive capacity and nigrostriatal dopamine function

    Gilliam, P.E.

    1984-01-01

    This investigation examined the effects of aging on reactive capacity (reaction time), and striatal dopamine function in the same animals. Twenty, 3 month old, and twenty, 24 month old, male Sprague-Dawley rats were trained in a reactive capacity test to quickly release a lever, in response to an auditory and visual stimulus, in order to avoid footshocks. The young animals were tested at 3, 6, and 9 months of age, while the Old animals were tested at 18, 21, and 24 months of age. Twenty-four hours after the last testing session the animals were sacrificed and their striata dissected for biochemical assays. A [ 3 H]-spiperone receptor binding assay was performed to determine the density and affinity of striatial D-2 receptors. It was hypothesized that the improvement in reactive capacity performance of the Old animals over days was due to their ability to compensate for their decrease in receptor density by an increase in the production and utilization of dopamine. Significant positive correlations were also found between reactive capacity performance and receptor density as well as between reactive capacity and the ratio of DOPAC + HVA/DA

  17. Effects of imposed monitoring and blunting strategies on emotional reactivity

    Muris, Peter; Jong, de Peter; Merckelbach, Harald; van Zuuren, Florence J.

    1994-01-01

    The present study examined the effects of imposed monitoring and blunting coping strategies on emotional reactivity in 40 subjects who prepared themselves for upcoming neutral and aversive slides. Besides subjective indices, electrodermal measures and eye blink startle responses were used to

  18. Effects of proline on photosynthesis, root reactive oxygen species ...

    Effects of 0.2 mM proline applied to saline nutrient solution on biomass, chlorophyll content, photosynthetic parameters, reactive oxygen species and antioxidant enzymes activities of two melon cultivars (cv. Yuhuang and cv. Xuemei) were examined. Results indicate that exogenous proline increased the fresh and dry ...

  19. The ionising radiation effect on reactivation of antibiotics

    Dikij, I.L.; Manskij, A.A.; Krasnopyorova, A.P.

    2002-01-01

    The effect of gamma-radiation on the molecular structure of antibiotics was studied with a view to extending their useful life beyond the current expiration period. The following antibiotics were examined: penicillin, bicillin-3,5, streptomycine, and ampioxe. The samples were irradiated by Co-60 gamma-radiation from a research irradiator. Doses of 0.1, 1, 5, 7, and 10 Gy were applied. The processes were elucidated using the classical method of 2-divisible serial dilutions and IR-spectroscopy. All the measurements were carried out at 300 K. The IR-spectra revealed that the chemical structure of new and old antibiotics is identical; the change in the antibiotic activity is generally a result of deformation of the molecule or change in its conformation; the reactivation process returns the molecule to its previous state and the activity of antibiotic after reactivation meets established standards. Hence, this method can be used for the reactivation of expired antibiotics

  20. Studies on the ion-exchange behavior of chromium ferrocyanide

    Malik, W U; Srivastava, S K; Singh, Raj Pal; Kumar, Satish [Roorkee Univ. (India). Dept. of Chemistry

    1977-01-01

    The sorption of univalent, bivalent and trivalent ions has been studied on chromium ferrocyanide gel. The distribution of various metal cations were determined by shaking the exchanger (0.1 g) and 20 ml of 0.005M metal ion solution of pH 2-3, until equilibrium was attained. The concentration of Pb/sup 2 +/, Cu/sup 2 +/, Mn/sup 2 +/, Ni/sup 2 +/, Mg/sup 2 +/ and Al/sup 3 +/ were determined by EDTA, ZrO/sup 2 +/, Th/sup 4 +/, UO/sup 2 +/ and Fe/sup 2 +/ were estimated spectrophotometrically and radiometric methods were used for Rb/sup +/, Cs/sup +/, Tl/sup +/, Ag/sup +/, Zn/sup 2 +/, Co/sup 2 +/, Cd/sup 2 +/, Hg/sup 2 +/ and Fe/sup 3 +/ metal ions. The distribution coefficients of various univalent, bivalent and trivalent metal ions (0.002M) were also determined as a function of NH/sub 4/NO/sub 3/ and HNO/sub 3/ concentrations and pH. The studies reveal a high sorption capacity for Cs/sup +/, Tl/sup +/, Ag/sup +/, Cu/sup 2 +/, Zn/sup 2 +/, Cd/sup 2 +/, Fe/sup 3 +/ and Th/sup 4 +/. The sorption of monovalent cations show purely ion exchange mechanism while the uptake of bivalent and trivalent cations is non-equivalent in nature. Single elution of Rb/sup +/, Cs/sup +/ and Tl/sup +/ has been performed from the columns of this exchanger and the recovery is almost complete in all the cases. Cu/sup 2 +/ and Ag/sup +/ get completely adsorbed on the gel column and their elution is not possible probably due to the formation of some new solid phases. Depending on the Ksub(d) values of the metal ions, a large number of separations of radiochemical as well as analytical importance can be performed on the columns of this exchanger material. It is apparent from the Ksub(d) values that a number of separations as Hg/sup 2 +/ from Mg/sup 2 +/, Ca/sup 2 +/ and Pb/sup 2 +/; Mg/sup 2 +/ from Mn/sup 2 +/: Fe/sup 3 +/ from Al/sup 3 +/; and Th/sup 4 +/ from ZrO/sup 2 +/ can be performed on the columns of this exchanger.

  1. Moderator temperature effects on reactivity of HEU core of MNSR

    Ahmad, Siraj-ul-Islam; Sahibzada, Tasveer Muhammad

    2012-01-01

    Highlights: ► The MNSR core was analyzed to see the cross section effects on moderator temperature coefficient of reactivity. ► WIMS-D code was used for cell calculations. ► The 3D diffusion theory code PRIDE was first validated using IAEA benchmark problem and then used for analysis of MNSR. ► The differences among results for various libraries were discussed. -- Abstract: In this article we report on analyses that were performed to investigate the influence of cross section differences among libraries released by various centers on reactivity of Miniature Neutron Source Reactors. The 3D model of the core was developed with WIMS-D and PRIDE codes and six cross section libraries were used including JENDL-3.2, JEF-2.2, JEFF-3.3, ENDF/B-VI and ENDF/B-VII, and IAEA library. It was observed that all the libraries predict the reactivity within 10%, with IAEA library giving minimum reactivity worth, and JEF-2.2 data library resulted in highest worth.

  2. The use of composite ferrocyanide materials for treatment of high salinity liquid radioactive wastes rich in cesium isotopes

    Toropov, Andrey S. [National Nuclear Centre of the Republic of Kazakhstan, Kurchatov (Kazakhstan); Shakarim Semey State Univ. (Kazakhstan); Satayeva, Aliya R. [Shakarim Semey State Univ. (Kazakhstan); Mikhalovsky, Sergey [Nazarbayev Univ. (Kazakhstan); Brighton Univ. (United Kingdom); Cundy, Andrew B. [Brighton Univ. (United Kingdom)

    2014-07-01

    The use of composite materials based on metal ferrocyanides combined with natural mineral sorbents for treatment of high salinity Cs-containing liquid radioactive waste (LRW) was investigated. The study indicated that among the investigated composites, the best sorption characteristics for Cs were shown by materials based on copper ferrocyanide. Several factors affecting the removal of cesium from LRW, namely total salt content, pH and organic matter content, were also investigated. High concentrations of complexing organic matter significantly reduced the sorption capacity of ferrocyanide sorbents.

  3. Novel approaches based on ultrasound for treatment of wastewater containing potassium ferrocyanide.

    Jawale, Rajashree H; Tandale, Akash; Gogate, Parag R

    2017-09-01

    Industrial wastewaters containing biorefractory compounds like cyanide offer significant environmental problems attributed to the fact that the conventional methods have limited effectiveness and hence developing efficient treatment approaches is an important requirement. The present work investigates the use of novel treatment approach of ultrasound (US) combined with advanced oxidation techniques for the degradation of potassium ferrocyanide (KFC) for the first time. An ultrasonic bath equipped with longitudinal horn (1kW rated power and 25kHz frequency) has been used. The effect of initial pH (2-9) on the progress of degradation has been investigated initially and subsequently using the optimized pH, effect of addition of hydrogen peroxide (ratio of KFC:H 2 O 2 varied over the range of 1:0.5-1:5) and TiO 2 in the presence of H 2 O 2 (1:1 ratio by weight of TiO 2 ) as process intensifying approach has been studied. Combination of ultrasonic irradiation with ozone (O 3 ) (100-400mg/h) and ultraviolet irradiation (UV) has also been investigated. Use of combination of US with H 2 O 2, H 2 O 2 +TiO 2 and ozone resulted in extent of KFC degradation as 54.2%, 74.82% and 82.41% respectively. Combination of US with both UV and ozone was established to be the best approach yielding 92.47% degradation. The study also focused on establishing kinetic rate constants for all the treatment approaches which revealed that all the approaches followed first order kinetic mechanism with higher rate constants for the combination approaches. Overall, it has been conclusively established that ultrasound based combined treatment schemes are very effective for the treatment of KFC containing wastewaters. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Modeling food matrix effects on chemical reactivity: Challenges and perspectives.

    Capuano, Edoardo; Oliviero, Teresa; van Boekel, Martinus A J S

    2017-06-29

    The same chemical reaction may be different in terms of its position of the equilibrium (i.e., thermodynamics) and its kinetics when studied in different foods. The diversity in the chemical composition of food and in its structural organization at macro-, meso-, and microscopic levels, that is, the food matrix, is responsible for this difference. In this viewpoint paper, the multiple, and interconnected ways the food matrix can affect chemical reactivity are summarized. Moreover, mechanistic and empirical approaches to explain and predict the effect of food matrix on chemical reactivity are described. Mechanistic models aim to quantify the effect of food matrix based on a detailed understanding of the chemical and physical phenomena occurring in food. Their applicability is limited at the moment to very simple food systems. Empirical modeling based on machine learning combined with data-mining techniques may represent an alternative, useful option to predict the effect of the food matrix on chemical reactivity and to identify chemical and physical properties to be further tested. In such a way the mechanistic understanding of the effect of the food matrix on chemical reactions can be improved.

  5. Reactivity effects of fission product decay in PWRs

    Aragones, J.M.; Ahnert, C.

    1988-01-01

    The purpose of the work reported in this paper is to analyze the effects of fission product chains with radioactive decay on the reactivity in pressurized water reactor (PWR) cores, calculating their accumulation and absorption rates along fuel burnup at continuous operation and after shutdown periods extending from 1 day to a few months. The authors PWR version of the WIMS-D4 code is first used to obtain the individual number densities, absorption rates, and averaged cross sections for every nuclide of the fission product chains with significant decay rates, as a function of fuel burnup at continuous irradiation. Next, by an auxiliary ad hoc code, these data, have been processed together with the required one for fissile nuclides and boron, also taken from WIMS at each burnup step, to calculate the average or effective values relevant for the analysis and the decay and change in overall absorption after several shutdown times. (1) The reactivity effect of fission product decay changes significantly with the shutdown time. The maximum absorption increase by decay is reached in ∼ 10 days' shutdown. (2) The dependence with fuel type, enrichment, and burnup is slight, but the change with previous power density is nearly linear, which might be significant after coast-down in previous cycles. (3) For long shutdown periods, the overall reactivity effect of decay in the three fission product chains considered is much less than if only the samarium peak due to 149 Nd is considered

  6. Determination of static and dynamic reactivity effects in KNK II

    Essig, C.

    1987-11-01

    In the frame of a pre-study of the KNK II test program two series of experiments related to inherent safety characteristics of sodium cooled breeder reactors have been elaborated, which are one basis for the performance of experiments of the Loss Of Flow (LOF) type and the Loss Of Heat Sink (LOHS) type. Tests of this type at KNK II would -different from the earlier tests at RAPSODIE and EBR-II- provide a demonstration of the inherently safe performance in case of a significantly non-zero Doppler effect. With a suitable execution, the foreseen series of experiments allow, as explained in this report, a substantial separation of the reactivity contributions and the determination of reactivity effects, i.e. the time constants of the recouplings. The performance and evaluation of these experiments with respect to the inherent safety potential will once more underline the distinguished role of KNK II for the development of fast breeders [de

  7. Radiation enhanced reactivation of herpes simplex virus: effect of caffeine.

    Hellman, K B; Lytle, C D; Bockstahler, L E

    1976-09-01

    Ultaviolet enhanced (Weigle) reactivation of UV-irradiated herpes simplex virus in UV-irradiated CV-1 monkey kidney cell monolayers was decreased by caffeine. X-ray enhanced reactivation of UV-irradiated virus in X-irradiated monolayers (X-ray reactivation) and UV- or X-ray-inactivated capacity of the cells to support unirradiated virus plaque formation were unaffected by caffeine. The results suggest that a caffeine-sensitive process is necessary for the expression of Weigle reactivation for herpes virus. Since cafeine did not significantly affect X-ray reactivation, different mechanisms may be responsible for the expression of Weigle reactivation and X-ray reactivation.

  8. Radiation enhaced reactivation of herpes simplex virus: effect of caffeine

    Hellman, K.B.; Lytle, C.D.; Bockstahler, L.E.

    1976-01-01

    Ultraviolet enhanced (Weigle) reactivation of UV-irradiated herpes simplex virus in UV-irradiated CV-1 monkey kidney cell monolayers was decreased by caffeine. X-ray enhanced reactivation of UV-irradiated virus in X-irradiated monolayers (X-ray reactivation) and UV- or X-ray-inactivated capacity of the cells to support unirradiated virus plaque formation were unaffected by caffeine. The results suggest that a caffeine-sensitive process is necessary for the expression of Weigle reactivation for herpes virus. Since caffeine did not significantly affect X-ray reactivation, different mechanisms may be responsible for the expression of Weigle reactivation and X-ray reactivation

  9. Formation, decomposition and cesium adsorption mechanisms of highly alkali-tolerant nickel ferrocyanide prepared by interfacial synthesis

    Ichikawa, Tsuneki; Yamada, Kazuo; Osako, Masahiro; Haga, Kazuko

    2017-01-01

    Highly alkali-tolerant nickel ferrocyanide was prepared as an adsorbent for preventing the leaching of radioactive cesium from municipal solid waste incinerator fly ash containing large amounts of calcium hydroxide and potassium chloride, which act as an alkaline source and the suppressor for cesium adsorption, respectively. Nickel ferrocyanide prepared by contacting concentrated nickel and ferrocyanide solutions without mixing adsorbed cesium ions in alkaline conditions even the concentration of coexisting potassium ions was more than ten thousand times higher than that of the cesium ions. Large particles of nickel ferrocyanide slowly grew at the interface between the two solutions, which reduced the surface energy of the particles and therefore increased the alkali tolerance. The interfacially-synthesized nickel ferrocyanide was possible to prevent the leaching of radioactive cesium from cement-solidified fly ash for a long period. The mechanisms of the formation, selective cesium adsorption, and alkali-induced decomposition of the nickel ferrocyanide were elucidated. Comparison of the cesium adsorption mechanism with that of the other adsorbents revealed that an adsorbent can selectively adsorb cesium ions without much interference from potassium ions, if the following conditions are fulfilled. 1) The adsorption site is small enough for supplying sufficient electrostatic energy for the dehydration of ions adsorbed. 2) Both the cesium and potassium ions are adsorbed as dehydrated ions. 3) The adsorption site is flexible enough for permitting the penetration of dehydrated ions with the size comparable to that of the site. (author)

  10. Characterization, Leaching, and Filtrations Testing of Ferrocyanide Tank sludge (Group 8) Actual Waste Composite

    Fiskum, Sandra K.; Billing, Justin M.; Crum, J. V.; Daniel, Richard C.; Edwards, Matthew K.; Shimskey, Rick W.; Peterson, Reid A.; MacFarlan, Paul J.; Buck, Edgar C.; Draper, Kathryn E.; Kozelisky, Anne E.

    2009-02-28

    This is the final report in a series of eight reports defining characterization, leach, and filtration testing of a wide variety of Hanford tank waste sludges. The information generated from this series is intended to supplement the Waste Treatment and Immobilization Plant (WTP) project understanding of actual waste behaviors associated with tank waste sludge processing through the pretreatment portion of the WTP. The work described in this report presents information on a high-iron waste form, specifically the ferrocyanide tank waste sludge. Iron hydroxide has been shown to pose technical challenges during filtration processing; the ferrocyanide tank waste sludge represented a good source of the high-iron matrix to test the filtration processing.

  11. Characterization, Leaching, and Filtrations Testing of Ferrocyanide Tank sludge (Group 8) Actual Waste Composite

    Fiskum, Sandra K.; Billing, Justin M.; Crum, J.V.; Daniel, Richard C.; Edwards, Matthew K.; Shimskey, Rick W.; Peterson, Reid A.; MacFarlan, Paul J.; Buck, Edgar C.; Draper, Kathryn E.; Kozelisky, Anne E.

    2009-01-01

    This is the final report in a series of eight reports defining characterization, leach, and filtration testing of a wide variety of Hanford tank waste sludges. The information generated from this series is intended to supplement the Waste Treatment and Immobilization Plant (WTP) project understanding of actual waste behaviors associated with tank waste sludge processing through the pretreatment portion of the WTP. The work described in this report presents information on a high-iron waste form, specifically the ferrocyanide tank waste sludge. Iron hydroxide has been shown to pose technical challenges during filtration processing; the ferrocyanide tank waste sludge represented a good source of the high-iron matrix to test the filtration processing

  12. The bystander effect: is reactive oxygen species the driver?

    Szumiel, I.

    2003-01-01

    The paper reviews selected examples of the bystander effect, such as clonogenic survival decrease, chromosomal aberrations and mutations. The similarities and differences between the biological effects in directly targeted and bystander cells are briefly discussed. Also reviewed are the experimental data which support the role of reactive oxygen species (ROS), especially *O 2 - , as mediators of the bystander effect. Endogenously generated ROS, due to activation of NAD(P)H oxidases, play a kay role in the introduction of DNA damage in bystander cells. All the observed effects in bystander cells, such as alteration in gene expression patterns, chromosomal aberrations, sister chromatid exchanges, mutations, genome instability and neoplastic transformation are the consequence of DNA damage. (author)

  13. Identification of fast power reactivity effect in nuclear power reactor

    Efanov, A.I.; Kaminskas, V.A.; Lavrukhin, V.S.; Rimidis, A.P.; Yanitskene, D.Yu.

    1987-01-01

    A nuclear power reactor is an object of control with distributed parameters, characteristics of which vary during operation time. At the same time the reactor as the object of control has internal feedback circuits, which are formed as a result of the effects of fuel parameters and a coolant (pressure, temperature, steam content) on the reactor breeding properties. The problem of internal feedback circuit identification in a nuclear power reactor is considered. Conditions for a point reactor identification are obtained and algorithms of parametric identification are constructed. Examples of identification of fast power reactivity effect for the RBMK-1000 reactor are given. Results of experimental testing have shown that the developed method of fast power reactivity effect identification permits according to the data of normal operation to construct adaptive models for the point nuclear reactor, designed for its behaviour prediction in stationary and transition operational conditions. Therefore, the models considered can be used for creating control systems of nuclear power reactor thermal capacity (of RBMK type reactor, in particular) which can be adapted to the change in the internal feedback circuit characteristics

  14. Aqueous dye-sensitized solar cell electrolytes based on the ferricyanide-ferrocyanide redox couple

    Daeneke, Torben; Spiccia, Leone [School of Chemistry and ARC Centre of Excellence for Electromaterials Science, Monash University, Victoria (Australia); Uemura, Yu.; Koumura, Nagatoshi [Research Institute for Photovoltaic Technology, National Institute of Advanced Industrial Science and Technology AIST, Ibaraki (Japan); Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki (Japan); Duffy, Noel W. [CSIRO Energy Technology, Clayton, VIC (Australia); Mozer, Attila J. [School of Chemistry and ARC Centre of Excellence for Electromaterials Science, University of Wollongong, NSW (Australia); Bach, Udo [Department of Materials Engineering, Monash University, Victoria (Australia)

    2012-03-02

    Solar energy conversion efficiencies of over 4% have been achieved in DSCs constructed with aqueous electrolytes based on the ferricyanide-ferrocyanide redox couple, thereby avoiding the use of expensive, flammable and toxic solvents. This paradigm shift was made possible by the use of a hydrophobic organic carbazole dye. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Copper ferrocyanide functionalized magnetic nanoparticles using polyelectrolyte for the removal of cesium

    Yang, Hee Man; Lee, Kune Woo; Seo, Bum Kyoung; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    In the present study, magnetite nanoparticles were coated with copper ferrocyanide for the adsorption of radioactive Cs-137 in an aqueous solution through the grafting of polyethyleneimine. We describe the morphology, structure, and physical property of these nanoparticles. In addition, their ability to eliminate Cs-137 from water was also evaluated. Magnetic nanoadsorbents composed of a magnetic particles core and functional shell, which adsorb the contaminants, has attracted significant attention in environmental remediation owing to their high surface area and unique superparamagnetism. Since the nuclear accident at the Fukushima Daiichi nuclear power station in 2011, a huge amount of radioactive contaminants has been released into the environment. Among the various radioactive contaminants, cesium (Cs)-137 (137Cs) is the most apprehensive element owing to its long half-life (30.2 years), high solubility in water, and strong radiation emission in the form of gamma rays (γ-rays). Various methods such as ion exchange solvent extraction and precipitation are applied for the remediation of Cs-137 contaminated water. In particular, metal ferrocyanides show a high selectivity toward Cs-137. However, the very fine powder form of metal ferrocyanide causes a difficult separation from water through filtration.

  16. Intrusive sampling and testing of ferrocyanide tanks, Hanford Site, Richland, Washington: Environmental Assessment

    1992-02-01

    The proposed action involves intrusive sampling and testing of 24 Hanford Site single-shell waste tanks that contain ferrocyanide-nitrate/nitrite mixtures to determine the physical and chemical properties of the waste material. The Department of Energy (DOE) needs to take this action to help define the required controls to prevent or mitigate the potential for an accident during future characterization and monitoring of these tanks. Given the Unreviewed Safety Question associated with the consequences of a potential ferrocyanide nitrate/nitrite reaction, two safety assessments and this environmental assessment (EA) have been prepared to help ensure that the proposed action is conducted in a safe and environmentally sound manner. Standard operating procedures for sampling high-level waste tanks have been revised to reflect the potential presence of flammable or explosive mixtures in the waste. The proposed action would be conducted using nonsparking materials, spark resistant tools, and a portable containment enclosure (greenhouse) and plastic ground cover. The proposed activities involving Hanford Site ferrocyanide-containing tanks would be on land dedicated to DOE waste management

  17. The experimental study of digital reactivity meter with space effect elimination

    Xie, Y.Q.; Jian, Z.B.; Zhang, Y.S.

    1988-01-01

    The paper summarizes a digital reactivity measurement theory with space effect elimination. On the basis of the theory, we have prepared an on-line digital reactivity meter with space effect elimination. This system is composed of neutron detector and magnifying, data acquisition channel, monoplate microprocessor and data output channel. Measured results of reactivity using the method described in this paper are in agreement with measured results of reactivity using the pulsed neutron method and 'ρ-shape' method within experimental error. (author)

  18. Improvements of the base bleed effect using reactive particles

    Bournot, Herve; Daniel, Eric [Polytech' Marseille, IUSTI UMR CNRS 6595, 5, rue E. Fermi, Technopole de Chateau Gombert, 13453 Marseille cedex 13 (France); Cayzac, Roxan [Giat Industries, 7, Route de Guerry, F-18023 Bourges cedex (France)

    2006-11-15

    A numerical study of the base drag reduction of axisymmetric body projectiles in supersonic flight using a base bleed injection is presented in this paper. Unsteady computations of compressible viscous flow have been achieved in order to investigate the coupled effect of the bleed temperature and the bleed mass flow rate on the base pressure. The idea developed in the study, consists in the addition of metallic particles in the propellant composition used to provide the additional mass injected in order to obtain the lowest base drag. Indeed, for a low mass addition, a significant increase of the mixture energy is expected due to the particles combustion. Base flow with reactive two-phase injection is then simulated. Results show the ability of the method to describe such flows and the efficiency of the particles combustion to increase the base bleed reducing drag effect. (author)

  19. Sb(V reactivity with human blood components: redox effects.

    Silvana López

    Full Text Available We assessed the reactivity of Sb(V in human blood. Sb(V reactivity was determined using an HPLC-HG-AFS hyphenated system. Sb(V was partially reduced to Sb(III in blood incubation experiments; however, Sb(III was a highly unstable species. The addition of 0.1 mol L(-1 EDTA prevented Sb(III oxidation, thus enabling the detection of the reduction of Sb(V to Sb(III. The transformation of Sb(V to Sb(III in human whole blood was assessed because the reduction of Sb(V in human blood may likely generate redox side effects. Our results indicate that glutathione was the reducing agent in this reaction and that Sb(V significantly decreased the GSH/GSSG ratio from 0.32 ± 0.09 to 0.07 ± 0.03. Moreover, the presence of 200 ng mL(-1 of Sb(V increased the activity of superoxide dismutase from 4.4 ± 0.1 to 7.0 ± 0.4 U mL(-1 and decreased the activity of glutathione peroxidase from 62 ± 1 to 34 ± 2 nmol min(-1 mL(-1.

  20. Preliminary conceptual design for the destruction of organic/ferrocyanide constituents in the Hanford tank waste with low-temperature hydrothermal processing

    Schmidt, A.J.; Jones, E.O.; Orth, R.J.; Cox, J.L.; Elmore, M.E.; Neuenschwander, G.G.; Hart, T.R.; Meng, C.D.

    1993-05-01

    Hydrothermal processing (HTP) is a thermal-chemical processing method that can be employed to destroy organic and ferrocyanide constituents in Hanford tank waste by using the abundant existing oxidants in the tank waste such as nitrite and nitrate. Use-temperature HTP effectively destroys organics at temperatures from 250 degree C to 400 degree C to eliminate safety hazards and improve further processing. This proposal describes a conceptual design of a low-temperature HTP system (including a preliminary flow diagram and plot plan, equipment descriptions and sizes, utility requirements, and costs); the experimental work supporting this effort at Pacific Northwest Laboratory (PNL); the reaction chemistry and kinetics; the technical maturity of the process; and a preliminary assessment of maintenance, operation, and safety of a system. Nitrate destruction using organic reductants is also described. The low-temperature hydrothermal program at PNL was initiated in January 1993. It is part of an overall program to develop organic destruction technologies, which was originally funded by Hanford's Tank Waste Remediation System program and then was transferred to the Initial Pretreatment (IPM) project. As described in the document, low-temperature HTP (1) meets or exceeds system requirements in organic, ferrocyanide, and nitrate destruction, and processing rate; (2) is technically mature with little additional technology development required; (3) is a simple process with good operational reliability; (4) is flexible and can be easily integrated in the system; (5) has reasonable costs and utility requirements; and (6) is safe and environmentally-benign

  1. Structural and reactivity models for copper oxygenases: cooperative effects and novel reactivities.

    Serrano-Plana, Joan; Garcia-Bosch, Isaac; Company, Anna; Costas, Miquel

    2015-08-18

    Dioxygen is widely used in nature as oxidant. Nature itself has served as inspiration to use O2 in chemical synthesis. However, the use of dioxygen as an oxidant is not straightforward. Its triplet ground-state electronic structure makes it unreactive toward most organic substrates. In natural systems, metalloenzymes activate O2 by reducing it to more reactive peroxide (O2(2-)) or superoxide (O2(-)) forms. Over the years, the development of model systems containing transition metals has become a convenient tool for unravelling O2-activation mechanistic aspects and reproducing the oxidative activity of enzymes. Several copper-based systems have been developed within this area. Tyrosinase is a copper-based O2-activating enzyme, whose structure and reactivity have been widely studied, and that serves as a paradigm for O2 activation at a dimetal site. It contains a dicopper center in its active site, and it catalyzes the regioselective ortho-hydroxylation of phenols to catechols and further oxidation to quinones. This represents an important step in melanin biosynthesis and it is mediated by a dicopper(II) side-on peroxo intermediate species. In the present accounts, our research in the field of copper models for oxygen activation is collected. We have developed m-xylyl linked dicopper systems that mimick structural and reactivity aspects of tyrosinase. Synergistic cooperation of the two copper(I) centers results in O2 binding and formation of bis(μ-oxo)dicopper(III) cores. These in turn bind and ortho-hydroxylate phenolates via an electrophilic attack of the oxo ligand over the arene. Interestingly the bis(μ-oxo)dicopper(III) cores can also engage in ortho-hydroxylation-defluorination of deprotonated 2-fluorophenols, substrates that are well-known enzyme inhibitors. Analysis of Cu2O2 species with different binding modes show that only the bis(μ-oxo)dicopper(III) cores can mediate the reaction. Finally, the use of unsymmetric systems for oxygen activation is a field

  2. Reinstatement versus Reactivation Effects on Active Memory in Infants.

    Adler, Scott A.; Rovee-Collier, Carolyn; Wilk, Amy

    2000-01-01

    Four experiments examined whether reinstatement and reactivation reminder paradigms affected memory performance of 102 three-month-olds. Results indicated that a single reinstatement protracted retention twice as long after training as a single reactivation. The novelty of the reminder stimulus also affected duration and specificity of memory in…

  3. Copper Ferrocyanide Functionalized Core-Shell Magnetic Silica Composites for the Selective Removal of Cesium Ions from Radioactive Liquid Waste.

    Lee, Hyun Kyu; Yang, Da Som; Oh, Wonzin; Choi, Sang-June

    2016-06-01

    The copper ferrocyanide functionalized core-shell magnetic silica composite (mag@silica-CuFC) was prepared and was found to be easily separated from aqueous solutions by using magnetic field. The synthesized mag@silica-CuFC composite has a high sorption ability of Cs owing to its strong affinity for Cs as well as the high surface area of the supports. Cs sorption on the mag@silica-CuFC composite quickly reached the sorption equilibrium after 2 h of contact time. The effect of the presence of salts with a high concentration of up to 3.5 wt% on the efficiency of Cs sorption onto the composites was also studied. The maximum sorption ability was found to be maintained in the presence of up to 3.5 wt% of NaCl in the solution. Considering these results, the mag@silica-CuFC composite has great potential for use as an effective sorbent for the selective removal of radioactive Cs ions.

  4. Environmental life cycle assessment of permeable reactive barriers: effects of construction methods, reactive materials and groundwater constituents.

    Mak, Mark S H; Lo, Irene M C

    2011-12-01

    The effects of the construction methods, materials of reactive media and groundwater constituents on the environmental impacts of a permeable reactive barrier (PRB) were evaluated using life cycle assessment (LCA). The PRB is assumed to be installed at a simulated site contaminated by either Cr(VI) alone or Cr(VI) and As(V). Results show that the trench-based construction method can reduce the environmental impacts of the remediation remarkably compared to the caisson-based method due to less construction material consumption by the funnel. Compared to using the zerovalent iron (Fe(0)) and quartz sand mixture, the use of the Fe(0) and iron oxide-coated sand (IOCS) mixture can reduce the environmental impacts. In the presence of natural organic matter (NOM) in groundwater, the environmental impacts generated by the reactive media were significantly increased because of the higher usage of Fe(0). The environmental impacts are lower by using the Fe(0) and IOCS mixture in the groundwater with NOM, compared with using the Fe(0) and quartz sand mixture. Since IOCS can enhance the removal efficiency of Cr(VI) and As(V), the usage of the Fe(0) can be reduced, which in turn reduces the impacts induced by the reactive media.

  5. Pleiotropic Effects of Biguanides on Mitochondrial Reactive Oxygen Species Production

    Alena Pecinova

    2017-01-01

    Full Text Available Metformin is widely prescribed as a first-choice antihyperglycemic drug for treatment of type 2 diabetes mellitus, and recent epidemiological studies showed its utility also in cancer therapy. Although it is in use since the 1970s, its molecular target, either for antihyperglycemic or antineoplastic action, remains elusive. However, the body of the research on metformin effect oscillates around mitochondrial metabolism, including the function of oxidative phosphorylation (OXPHOS apparatus. In this study, we focused on direct inhibitory mechanism of biguanides (metformin and phenformin on OXPHOS complexes and its functional impact, using the model of isolated brown adipose tissue mitochondria. We demonstrate that biguanides nonspecifically target the activities of all respiratory chain dehydrogenases (mitochondrial NADH, succinate, and glycerophosphate dehydrogenases, but only at very high concentrations (10−2–10−1 M that highly exceed cellular concentrations observed during the treatment. In addition, these concentrations of biguanides also trigger burst of reactive oxygen species production which, in combination with pleiotropic OXPHOS inhibition, can be toxic for the organism. We conclude that the beneficial effect of biguanides should probably be associated with subtler mechanism, different from the generalized inhibition of the respiratory chain.

  6. Quantitative measurement of cyanide complexes in simulated and actual Hanford ferrocyanide wastes

    Bryan, S.A.; Pool, K.H.; Sell, R.L.; Bryan, S.L.

    1994-01-01

    Cyanide-containing radioactive waste from radiocesium scavenging processes conducted during the 1950's at Hanford is currently stored in 24 single shell tanks. As part of ongoing tank characterization efforts, the quantity and chemical form of cyanide in these tanks need to be determined. This report summarizes the results of studies conducted at Pacific Northwest Laboratory (PNL) under contract to Westinghouse Hanford Company (WHC) to develop methods for the quantification of total cyanide and identification of major cyanide-containing species in Ferrocyanide Tank Waste. Results from the application of FTIR, IC, and microdistillation procedures to simulated and actual Hanford waste are presented and compared where applicable

  7. Supporting of some ferrocyanides on polyacrylonitrile (PAN) binding polymer and their application for cesium treatment

    Someda, H.H.; El Zahhar, A.A.; Shehata, M.K.; El-Naggar, H.A.

    2001-01-01

    Transition metal ferrocyanides were supported on polyacrylonitrile (PAN) as a binding polymer and were used for removal of radiocesium. The sorption capacity were determined for each sorbent and was found to be 1.22 and 0.65 meq/gm for KZnHCF-PAN and KCuHCF-PAN respectively. Different parameters affecting the sorption process were studied as chemical nature of the active solution, presence of competing ions and flow rate of feed solution. The regeneration of the used sorbent was studied using different solutions and also reusing the regenerated sorbent in other cycle up to four cycles (authors)

  8. Determination of Metastable Zone Width, Induction Period and Interfacial Energy of a Ferroelectric Crystal - Potassium Ferrocyanide Trihydrate (KFCT

    R. Kanagadurai

    2010-01-01

    Full Text Available An order-disorder type potassium ferrocyanide trihydrate (KFCT is a coordination compound forming lemon- yellow monoclinic ferroelectric crystals with curie temperature 251 K. KFCT crystals have been grown by temperature lowering solution growth technique. Solubility of KFCT has been determined for various temperatures. Metastable zone width, induction period and interfacial energy were determined for the aqueous solution of KFCT. Bulk crystal of potassium ferrocyanide trihydrate was grown with the optimized growth parameters. The grown crystal possesses good optical transmission in the entire UV-Visible region

  9. Use of potassium ferrocyanide as habit modifier in the size reduction and phase modification of ammonium nitrate crystals in slurries.

    Vargeese, Anuj A; Joshi, Satyawati S; Krishnamurthy, V N

    2010-08-15

    Ammonium nitrate (AN) is an inorganic crystalline compound used as a solid propellant oxidizer and as a nitrogenous fertilizer. The practical use of AN as solid propellant oxidizer is restricted due to the near room temperature polymorphic phase transition and hygroscopicity. A good deal of effort has been expended for last many years to stabilize the polymorphic transitions of AN, so as to minimize the storage difficulties of AN based fertilizers and to achieve more environmentally benign propellant systems. Also, particles with aspect ratio nearer to one are a vital requirement in fertilizer and propellant industries. In the present study AN is crystallized in presence of trace amount of potassium ferrocyanide (K(4)Fe(CN)(6)) crystal habit modifier and kept for different time intervals. And the effect of K(4)Fe(CN)(6) on the habit and phase modification of AN was studied. Phase modified ammonium nitrate (PMAN) with a particle aspect ratio nearer to one was obtained by this method and the reasons for this modifications are discussed. The morphology changes were studied by SEM, the phase modifications were studied by DSC and the structural properties were studied by powder XRD. Copyright 2010 Elsevier B.V. All rights reserved.

  10. Effect of nonsteroidal antiinflammatory drugs on the C-reactive protein level in rheumatoid arthritis

    Tarp, Simon; Bartels, Else M.; Bliddal, Henning

    2012-01-01

    To evaluate the effects of oral nonsteroidal antiinflammatory drugs (NSAIDs) on C-reactive protein (CRP) levels in rheumatoid arthritis (RA) patients, with a prespecified focus on the different NSAIDs.......To evaluate the effects of oral nonsteroidal antiinflammatory drugs (NSAIDs) on C-reactive protein (CRP) levels in rheumatoid arthritis (RA) patients, with a prespecified focus on the different NSAIDs....

  11. Effect of Pitavastatin on Vascular Reactivity in Hypercholesterolemic Rabbits

    Almeida, Eros Antonio de, E-mail: erosaa@cardiol.br; Ozaki, Michiko Regina [Universidade Estadual de Campinas, Campinas, SP (Brazil)

    2014-07-15

    Pitavastatin is the newest statin available in Brazil and likely the one with fewer side effects. Thus, pitavastatin was evaluated in hypercholesterolemic rabbits in relation to its action on vascular reactivity. To assess the lowest dose of pitavastatin necessary to reduce plasma lipids, cholesterol and tissue lipid peroxidation, as well as endothelial function in hypercholesterolemic rabbits. Thirty rabbits divided into six groups (n = 5): G1 - standard chow diet; G2 - hypercholesterolemic diet for 30 days; G3 - hypercholesterolemic diet and after the 16{sup th} day, diet supplemented with pitavastatin (0.1 mg); G4 - hypercholesterolemic diet supplemented with pitavastatin (0.25 mg); G5 - hypercholesterolemic diet supplemented with pitavastatin (0.5 mg); G6 - hypercholesterolemic diet supplemented with pitavastatin (1.0 mg). After 30 days, total cholesterol, HDL, triglycerides, glucose, creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT) were measured and LDL was calculated. In-depth anesthesia was performed with sodium thiopental and aortic segments were removed to study endothelial function, cholesterol and tissue lipid peroxidation. The significance level for statistical tests was 5%. Total cholesterol and LDL were significantly elevated in relation to G1. HDL was significantly reduced in G4, G5 and G6 when compared to G2. Triglycerides, CK, AST, ALT, cholesterol and tissue lipid peroxidation showed no statistical difference between G2 and G3-G6. Significantly endothelial dysfunction reversion was observed in G5 and G6 when compared to G2. Pitavastatin starting at a 0.5 mg dose was effective in reverting endothelial dysfunction in hypercholesterolemic rabbits.

  12. Effect of Pitavastatin on Vascular Reactivity in Hypercholesterolemic Rabbits

    Eros Antonio de Almeida

    2014-07-01

    Full Text Available Background: Pitavastatin is the newest statin available in Brazil and likely the one with fewer side effects. Thus, pitavastatin was evaluated in hypercholesterolemic rabbits in relation to its action on vascular reactivity. Objective: To assess the lowest dose of pitavastatin necessary to reduce plasma lipids, cholesterol and tissue lipid peroxidation, as well as endothelial function in hypercholesterolemic rabbits. Methods: Thirty rabbits divided into six groups (n = 5: G1 - standard chow diet; G2 - hypercholesterolemic diet for 30 days; G3 - hypercholesterolemic diet and after the 16th day, diet supplemented with pitavastatin (0.1 mg; G4 - hypercholesterolemic diet supplemented with pitavastatin (0.25 mg; G5 - hypercholesterolemic diet supplemented with pitavastatin (0.5 mg; G6 - hypercholesterolemic diet supplemented with pitavastatin (1.0 mg. After 30 days, total cholesterol, HDL, triglycerides, glucose, creatine kinase (CK, aspartate aminotransferase (AST, alanine aminotransferase (ALT were measured and LDL was calculated. In-depth anesthesia was performed with sodium thiopental and aortic segments were removed to study endothelial function, cholesterol and tissue lipid peroxidation. The significance level for statistical tests was 5%. Results: Total cholesterol and LDL were significantly elevated in relation to G1. HDL was significantly reduced in G4, G5 and G6 when compared to G2. Triglycerides, CK, AST, ALT, cholesterol and tissue lipid peroxidation showed no statistical difference between G2 and G3-G6. Significantly endothelial dysfunction reversion was observed in G5 and G6 when compared to G2. Conclusion: Pitavastatin starting at a 0.5 mg dose was effective in reverting endothelial dysfunction in hypercholesterolemic rabbits.

  13. Effect of Pitavastatin on Vascular Reactivity in Hypercholesterolemic Rabbits

    Almeida, Eros Antonio de; Ozaki, Michiko Regina

    2014-01-01

    Pitavastatin is the newest statin available in Brazil and likely the one with fewer side effects. Thus, pitavastatin was evaluated in hypercholesterolemic rabbits in relation to its action on vascular reactivity. To assess the lowest dose of pitavastatin necessary to reduce plasma lipids, cholesterol and tissue lipid peroxidation, as well as endothelial function in hypercholesterolemic rabbits. Thirty rabbits divided into six groups (n = 5): G1 - standard chow diet; G2 - hypercholesterolemic diet for 30 days; G3 - hypercholesterolemic diet and after the 16 th day, diet supplemented with pitavastatin (0.1 mg); G4 - hypercholesterolemic diet supplemented with pitavastatin (0.25 mg); G5 - hypercholesterolemic diet supplemented with pitavastatin (0.5 mg); G6 - hypercholesterolemic diet supplemented with pitavastatin (1.0 mg). After 30 days, total cholesterol, HDL, triglycerides, glucose, creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT) were measured and LDL was calculated. In-depth anesthesia was performed with sodium thiopental and aortic segments were removed to study endothelial function, cholesterol and tissue lipid peroxidation. The significance level for statistical tests was 5%. Total cholesterol and LDL were significantly elevated in relation to G1. HDL was significantly reduced in G4, G5 and G6 when compared to G2. Triglycerides, CK, AST, ALT, cholesterol and tissue lipid peroxidation showed no statistical difference between G2 and G3-G6. Significantly endothelial dysfunction reversion was observed in G5 and G6 when compared to G2. Pitavastatin starting at a 0.5 mg dose was effective in reverting endothelial dysfunction in hypercholesterolemic rabbits

  14. Analytical estimation of control rod shadowing effect for excess reactivity measurement of HTTR

    Nakano, Masaaki; Fujimoto, Nozomu; Yamashita, Kiyonobu

    1999-01-01

    The fuel addition method is generally used for the excess reactivity measurement of the initial core. The control rod shadowing effect for the excess reactivity measurement has been estimated analytically for High Temperature Engineering Test Reactor (HTTR). 3-dimensional whole core analyses were carried out. The movements of control rods in measurements were simulated in the calculation. It was made clear that the value of excess reactivity strongly depend on combinations of measuring control rods and compensating control rods. The differences in excess reactivity between combinations come from the control rod shadowing effect. The shadowing effect is reduced by the use of plural number of measuring and compensating control rods to prevent deep insertion of them into the core. The measured excess reactivity in the experiments is, however, smaller than the estimated value with shadowing effect. (author)

  15. Treatment of liquid radioactive waste by adsorption of some radionuclides on calcite sand, volcanic ash and comparing it with nickel ferro-cyanide

    Takriti, S.; Ali, A. F.

    2009-09-01

    Adsorption of 137 Cs existed in the liquid radioactive waste on the calcite sand and volcanic ash has been investigated. X-ray studies of sand and ash were used to have more information about the geological composition. The geological results show that the sand used is calcium carbonate and the ash is uncrystalline old volcanic ash. The radioactive measurements indicated that the calcite sand able to adsorb the 137 Cs with weak bond that can not resist the water flow. Otherwise, the volcanic ash can maintain the 137 Cs for long time and the water flow can not liberate the 137 Cs adsorbed into the volcanic ash. The adsorption of 137 Cs on nickel ferro-cyanide was more effective than other compounds. (author)

  16. Report on the handling of safety information concerning flammable gases and ferrocyanide at the Hanford waste tanks

    1990-07-01

    This report discusses concerns safety issues, and management at Hanford Tank Farm. Concerns center on the issue of flammable gas generation which could ignite, and on possible exothermic reactions of ferrocyanide compounds which were added to single shell tanks in the 1950's. It is believed that information concerning these issues has been mis-handled and the problems poorly managed

  17. Report on the handling of safety information concerning flammable gases and ferrocyanide at the Hanford waste tanks

    1990-07-01

    This report discusses concerns safety issues, and management at Hanford Tank Farm. Concerns center on the issue of flammable gas generation which could ignite, and on possible exothermic reactions of ferrocyanide compounds which were added to single shell tanks in the 1950's. It is believed that information concerning these issues has been mis-handled and the problems poorly managed. (CBS)

  18. Effects of atorvastatin on human c reactive protein metabolism

    Statins are known to reduce plasma C-reactive protein (CRP) concentrations. Our goals were to define the mechanisms by which CRP was reduced by maximal dose atorvastatin. Eight subjects with combined hyperlipidemia (5 men and 3 postmenopausal women) were enrolled in a randomized, placebo-controlled...

  19. Effects of Experimenter Surveillance on Reactive Self-Monitoring.

    Belfiore, Phillip J.; And Others

    1989-01-01

    Worker reactivity patterns were examined in a study of two women with mild and moderate mental retardation who self-monitored their work productivity with and without external surveillance. Findings suggest that surveillance is a setting event that may be important in achieving and maintaining self-management program benefits. (MSE)

  20. Oral tartrazine challenge in childhood asthma: effect on bronchial reactivity.

    Hariparsad, D; Wilson, N; Dixon, C; Silverman, M

    1984-01-01

    Ten asthmatic children who gave a history of cough or wheeze after orange drinks, were tested for tartrazine sensitivity. On separate days, either oral tartrazine (1 mg) or a placebo capsule were administered double blind. Bronchial reactivity was measured before, 30 and 60 min after ingestion by means of a histamine-inhalation challenge test. There was no change in baseline lung function after tartrazine, but histamine sensitivity (PC20) increased significantly in four of the children. No response was obtained to a larger dose of tartrazine (10 mg) in four of the non-responders. Alteration in the bronchial reactivity after an oral challenge, appears to be a sensitive means of detecting tartrazine sensitivity.

  1. Effect of Strain on the Reactivity of Metal Surfaces

    Mavrikakis, Manos; Hammer, Bjørk; Nørskov, Jens Kehlet

    1998-01-01

    Self-consistent density functional calculations for the adsorption of O and CO, and the dissociation of CO on strained and unstrained Ru(0001) surfaces are used to show how strained metal surfaces have chemical properties that are significantly different from those of unstrained surfaces. Surface...... reactivity increases with lattice expansion, following a concurrent up-shift of the metal d states. Consequences for the catalytic activity of thin metal overlayers are discussed....

  2. Reactivity effect of spent fuel due to spatial distributions for coolant temperature and burnup

    Hayashi, T.; Yamane, Y. [Nagoya Univ., Dept. of Nuclear Engineering, Nagoya, Aichi (Japan); Suyama, K. [OECD/NEA, Paris (France); Mochizuki, H. [Japan Research Institute, Ltd., Tokyo (Japan)

    2002-03-01

    We investigated the reactivity effect of spent fuel caused by the spatial distributions of coolant temperature and burnup by using the integrated burnup calculation code system SWAT. The reactivity effect which arises from taking account of the spatial coolant temperature distribution increases as the average burnup increases, and reaches the maximum value of 0.69%{delta}k/k at 50 GWd/tU when the burnup distribution is concurrently considered. When the burnup distribution is ignored, the reactivity effect decreases by approximately one-third. (author)

  3. Analysis Of Temperature Effects On Reactivity Of The Rsg-Gas Core Using Silicide Fuels

    Surbakti, Tukiran; Pinem, Surian

    2001-01-01

    RSG-GAS has been operating using new silicide fuels so that it is necessary to estimate and to measure the effect of temperature on reactivity of the core. The parameters to be determined due to temperature effect are reactivity coefficient of moderator temperature, temperature coefficient of fuel element and power reactivity coefficient. By doing a couple compensation method, determination of reactivity coefficient as well as the reactivity coefficient of moderator temperature can be obtained. Furthermore, coefficient of the reactivity was successfully estimated using the combination of WIMS-D4 and Batan-2DIFF. The cell calculation was done by using WIMS-D4 code to get macroscopic cross section and Batan-2DIFF code is used for core calculation. The calculation and experimental results of reactivity coefficient do not show any deviation from RSG-GAS safety margin. The results are -2,84 sen/ o C, -1,29 sen/MW and -0,64 sen/ o C for reactivity coefficients of temperature, power, fuel element and moderator temperature, respectively. All of 3 parameters are absolutely met with safety criteria

  4. Evaluation of ferrocyanide anion exchange resins regarding the uptake of Cs+ ions and their regeneration

    Won, Hui Jun; Mooon, Jei Kwon; Jung, Chong Hun; Chung, Won Yang

    2008-01-01

    Ferrocyanide-anion exchange resin was prepared and the prepared ion exchange resins were tested on the ability to uptake Cs + ion. The prepared ion exchange resins were resin-KCoFC, resin-KNiFC, and resin-KCuFC. The three tested ion exchange resins showed ion exchange selectivity on the Cs + ion of the surrogate soil decontamination solution, and resin- KCoFC showed the best Cs + ion uptake capability among the tested ion exchange resins. The ion exchange behaviors were explained well by the modified Dubinin-Polanyi equation. A regeneration feasibility study of the spent ion exchange resins was also performed by the successive application of hydrogen peroxide and hydrazine. The desorption of the Cs + ion from the ion exchange resin satisfied the electroneutrality condition in the oxidation step; the desorption of the Fe 2+ ion in the reduction step could also be reduced by adding the K + ion

  5. Treatment of Simulated Soil Decontamination Waste Solution by Ferrocyanide-Anion Exchange Resin Beads

    Won, Hui Jun; Kim, Min Gil; Kim, Gye Nam; Jung, Chung Hun; Park, Jin Ho; Oh, Won Zin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2005-03-15

    Preparation of ferrocyanide-anion exchange resin and adsorption test of the prepared resin on the Cs{sup -} ion were performed. Adsorption capability of the prepared resin on the Cs{sup -} ion in the simulated citric acid based soil decontamination waste solution was 4 times greater than that of the commercial cation exchange resin. Adsorption equilibrium of the prepared resin on the Cs{sup -} ion reached within 360 minutes. Adsorption capability on the Cs{sup -} ion became to decrease above the necessary Co{sup 2-} ion concentration in the experimental range. Recycling test of the spent ion exchange resin by the successive application of hydrogen peroxide and hydrazine was also performed. It was found that desorption of Cs{sup -} ion from the resin occurred to satisfy the electroneutrality condition without any degradation of the resin.

  6. Cobalt and nickel ferrocyanide-functionalized magnetic adsorbent for the removal of radioactive cesium

    Hwang, Kyu Sun; Park, Chan Woo; Lee, Kune Woo; Yang, Hee Man [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, So Jin [Chungnam National University, Daejeon (Korea, Republic of)

    2017-03-15

    Cobalt ferrocyanide (CoFC) or nickel ferrocyanide (NiFC) magnetic nanoparticles (MNPs) were fabricated for efficient removal of radioactive cesium, followed by rapid magnetic separation of the absorbent from contaminated water. The Fe{sub 3}O{sub 4} nanoparticles, synthesized using a co-precipitation method, were coated with succinic acid (SA) to immobilize the Co or Ni ions through metal coordination to carboxyl groups in the SA. CoFC or NiFC was subsequently formed on the surfaces of the MNPs as Co or Ni ions coordinated with the hexacyanoferrate ions. The CoFC-MNPs and NiFC-MNPs possess good saturation magnetization values (43.2 emu∙g{sup -1} for the CoFC-MNPs, and 47.7 emu∙g{sup -1} for the NiFC-MNPs). The fabricated CoFC-MNPs and NiFC-MNPs were characterized by XRD, FT-IR, TEM, and DLS. The adsorption capability of the CoFC-MNPs and NiFC-MNPs in removing cesium ions from water was also investigated. Batch experiments revealed that the maximum adsorption capacity values were 15.63 mg∙g{sup -1} (CoFC-MNPs) and 12.11 mg∙g{sup -1} (NiFC-MNPs). Langmuir/ Freundlich adsorption isotherm equations were used to fit the experimental data and evaluate the adsorption process. The CoFC-MNPs and NiFC-MNPs exhibited a removal efficiency exceeding 99.09% for radioactive cesium from {sup 137}Cs solution (18-21 Bq∙g{sup -1}). The adsorbent selectively adsorbed {sup 137}Cs, even in the presence of competing cations.

  7. Relational victimization and proactive versus reactive relational aggression: The moderating effects of respiratory sinus arrhythmia and skin conductance.

    Wagner, Caitlin R; Abaied, Jamie L

    2015-01-01

    This research examined the moderating effect of the autonomic nervous system (ANS) on the associations between relational victimization and reactive and proactive relational aggression. Both branches of the ANS, the parasympathetic nervous system (indexed by respiratory sinus arrhythmia reactivity; RSA-Reactivity) and the sympathetic nervous system (indexed by skin conductance level reactivity; SCL-Reactivity), were examined. Emerging adults (N = 168) self-reported on relational victimization and proactive and reactive relational aggression; RSA-Reactivity and SCL-Reactivity were assessed in response to a laboratory stressor. Relational victimization predicted heightened reactive relational aggression given RSA augmentation/high SCL-Reactivity (i.e., coactivation) and RSA withdrawal/low SCL-Reactivity (i.e., coinhibition). In addition, relational victimization predicted heightened reactive relational aggression given RSA augmentation/low SCL-Reactivity (i.e., reciprocal parasympathetic activation). This study extends previous research on relational victimization and provides novel evidence that (a) exposure to relational victimization is associated with reactive relational aggression, but not proactive relational aggression, and (b) parasympathetic and sympathetic nervous system reactivity jointly moderate the link between relational victimization and reactive relational aggression. © 2015 Wiley Periodicals, Inc.

  8. Effective neutron temperature measurements in well moderated reactor by the reactivity coefficient method

    Raisic, N.; Klinc, T.

    1968-11-01

    The ratio of the reactivity changes of a nuclear reactor produced by successive introduction of two different neutron absorbers in the reactor core, has been measured and information on effective neutron temperature at a particular point obtained. Boron was used as a l/v absorber and cadmium as an absorber sensiti ve to neutron temperature. Effective neutron temperature distribution has been deduced by moving absorbers across the reactor core and observing the corresponding reactivity changes. (author)

  9. A revision of sensitivity analysis for small reactivity effects in ZPRs

    Ros, Paul; Blaise, Patrick; Gruel, Adrien; Leconte, Pierre

    2017-01-01

    Sensitivity analysis appears to be an important element for nuclear data improvement experiments. Indeed, it brings significant information on the contribution of the isotopes involved in the measurements performed in Zero Power Reactors (ZPRs), particularly oscillation measurements like in MINERVE, and its successor ZEPHYR (Zero power Experimental PHYsics Reactor), currently being designed at CEA. Oscillation measurements consist in oscillating a small sample made of separated isotopes (or irradiated fuels) in the core center. Then, two perturbations occur: a local one corresponding to the flux modification around the sample, and a global one which corresponds to the induced variation of reactivity. This variation of reactivity is either uncontrolled (open loop) or automatically compensated by an external pilot rod (closed loop) to keep the configuration in its critical state. Representativity studies are used in order to evaluate the pertinence of an experiment configuration versus a targeted application. For oscillation experiments, sensitivity of the reactivity effects to nuclear data is needed to obtain such coefficients. The Equivalent Generalized Perturbation Theory (EGPT) method, based on an approximation of the Generalized Perturbation. Theory, is currently applied in the ERANOS code for control rod insertions and other important variations of reactivity. However, such reactivity insertions induce consequent reactivity changes and variations of the flux, whereas oscillations induce maximal reactivity effects of 10 pcm (10 10 -5 Δk/k ) and consequently very local variations of the flux surrounding the sample. Therefore, such numerical methods are not necessarily adapted to the calculation of small reactivity effect sensitivities to nuclear data. The influence of peripheral isotopes (through their cross-sections) to central measurements is evaluated thanks to the deterministic EGPT method and the Monte-Carlo technique of correlated samples. Large

  10. Effective NH2-grafting on attapulgite surfaces for adsorption of reactive dyes

    Xue, Ailian; Zhou, Shouyong; Zhao, Yijiang; Lu, Xiaoping; Han, Pingfang

    2011-01-01

    Highlights: → We prepared a new amine functionalized adsorbent derived from clay-based material. → Attapulgite surface was modified with 3-aminopropyltriethoxysilane. → Some modification parameters affecting the adsorption potential were investigated. → Enhance the attapulgite adsorptive capacity for reactive dyes from aqueous solutions. - Abstract: The amine moiety has an important function in many applications, including, adsorption, catalysis, electrochemistry, chromatography, and nanocomposite materials. We developed an effective adsorbent for aqueous reactive dye removal by modifying attapulgite with an amino-terminated organosilicon (3-aminopropyltriethoxysilane, APTES). Surface properties of the APTES-modified attapulgite were characterized by the Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption. We evaluated the impact of solvent, APTES concentration, water volume, reaction time, and temperature on the surface modification. NH 2 -attapulgite was used to remove reactive dyes in aqueous solution and showed very high adsorption rates of 99.32%, 99.67%, and 96.42% for Reactive Red 3BS, Reactive Blue KE-R and Reactive Black GR, respectively. These powerful dye removal effects were attributed to strong electrostatic interactions between reactive dyes and the grafted NH 2 groups.

  11. Radial core expansion reactivity feedback in advanced LMRs: uncertainties and their effects on inherent safety

    Wigeland, R.A.; Moran, T.J.

    1988-01-01

    An analytical model for calculating radial core expansion, based on the thermal and elastic bowing of a single subassembly at the core periphery, is used to quantify the effect of uncertainties on this reactivity feedback mechanism. This model has been verified and validated with experimental and numerical results. The impact of these uncertainties on the safety margins in unprotected transients is investigated with SASSYS/SAS4A, which includes this model for calculating the reactivity feedback from radial core expansion. The magnitudes of these uncertainties are not sufficient to preclude the use of radial core expansion reactivity feedback in transient analysis

  12. Calculational study on reactivity effect of pipe intersections

    Okuno, Hiroshi; Naito, Yoshitaka; Kaneko, Toshiyuki.

    1995-03-01

    A simple formulation was proposed for evaluating the increment of reactivity due to the attachment of pipes to a vessel filled with fuel solution, and its validity was checked by numerical calculations. The formulation was based on the neutron balance equation which had been applied to the criticality safety analysis code MUTUAL for multi-unit systems, and the current formulation considered further the deviation of the representative neutron source point from the center of each pipe. The formulation was validated for models of 2- and 3-dimensional fuel systems by comparison with the precise calculations using the Monte Carlo code KENO-IV. For systems of pipes attached perpendicularly to the side of a cylindrical vessel, the size and number of negligible pipes were shown that corresponded to a very small increment (e.g. 0.3% Δk/k) of the neutron multiplication factor. (author)

  13. Electronic structure and related properties of ferrocyanide ion calculated by the SCF Xα-scattered wave method

    Guenzburger, D.; Maffeo, B.; Siqueira, M.L. de

    1975-08-01

    The SCF-XαSW method is used to calculate the electronic structure of the ferrocyanide ion. Optical transitions and X-Ray photoelectron emission are obtained from the energy level scheme and compared with experimental results. The charge density in the Fe nucleus is also computed and the result is correlated with isomer shift measurements made on this and other Fe complexes for which theoretical calculations have been performed

  14. Ferrocyanide Safety Program: Analysis of postulated energetic reactions and resultant aerosol generation in Hanford Site Waste Tanks

    Postma, A.K.; Dickinson, D.R.

    1995-09-01

    This report reviews work done to estimate the possible consequences of postulated energetic reactions in ferrocyanide waste stored in underground tanks at the Hanford Site. The issue of explosive reactions was raised in the 1987 Environmental Impact Statement (EIS), where a detonation-like explosion was postulated for the purpose of defining an upper bound on dose consequences for various disposal options. A review of the explosion scenario by the General Accounting Office (GAO) indicated that the aerosol generation and consequent radioactive doses projected for the explosion postulated in the EIS were understated by one to two orders of magnitude. The US DOE has sponsored an extensive study of the hazard posed by uncontrolled exothermic reactions in ferrocyanide waste, and results obtained during the past three years have allowed this hazard to be more realistically assessed. The objective of this report is to summarize the improved knowledge base that now indicates that explosive or vigorous chemical reactions are not credible in the ferrocyanide waste stored in underground tanks. This improved understanding supports the decision not to proceed with further analyses or predictions of the consequences of such an event or with aerosol tests in support of such predictions. 53 refs., 2 tabs

  15. Effect of drop jump technique on the reactive strength index.

    Struzik, Artur; Juras, Grzegorz; Pietraszewski, Bogdan; Rokita, Andrzej

    2016-09-01

    The basic drill of plyometric training aimed at improving lower limb power and jump height is a drop jump. This exercise can be performed using different techniques, which substantially affects jump variables. Therefore, the aim of this study was to compare the values of the reactive strength index (RSI) for countermovement drop jumps (CDJs) and bounce drop jumps (BDJs). The study was carried out in a group of 8 male youth basketball players. The tests were conducted using the AMTI BP600900 force plate to measure ground reaction forces and the Noraxon MyoMotion system to record kinematic data. Each player performed two CDJs and two BDJs from the height of 15, 30, 45 and 60 cm. The RSI was calculated as a ratio of jump height and contact time. Moreover, the RSI was determined for the amortization and take-off phases separately. Significant differences (p jumps from 30, 45 and 60 cm. Differences in RSI values for jumps from 15 cm were not significant. Furthermore, CDJ height values were significantly higher (p jump technique that is commonly performed by basketball players.

  16. Effect of drop jump technique on the reactive strength index

    Struzik Artur

    2016-09-01

    Full Text Available The basic drill of plyometric training aimed at improving lower limb power and jump height is a drop jump. This exercise can be performed using different techniques, which substantially affects jump variables. Therefore, the aim of this study was to compare the values of the reactive strength index (RSI for countermovement drop jumps (CDJs and bounce drop jumps (BDJs. The study was carried out in a group of 8 male youth basketball players. The tests were conducted using the AMTI BP600900 force plate to measure ground reaction forces and the Noraxon MyoMotion system to record kinematic data. Each player performed two CDJs and two BDJs from the height of 15, 30, 45 and 60 cm. The RSI was calculated as a ratio of jump height and contact time. Moreover, the RSI was determined for the amortization and take-off phases separately. Significant differences (p < 0.05 between RSI values for CDJs and BDJs were recorded for jumps from 30, 45 and 60 cm. Differences in RSI values for jumps from 15 cm were not significant. Furthermore, CDJ height values were significantly higher (p < 0.05 than the values recorded for BDJs. Times of contact, amortization and take-off during BDJs were significantly shorter (p < 0.05 than the respective values obtained for CDJs. Therefore, the use of the RSI to monitor plyometric training should be based on the drop jump technique that is commonly performed by basketball players.

  17. The effects of racial stressors and hostility on cardiovascular reactivity in African American and Caucasian men.

    Fang, C Y; Myers, H F

    2001-01-01

    This study examined the effects of race-related stressors and hostility on cardiovascular reactivity in 31 African American and 31 Caucasian men. Participants viewed 3 film excerpts that depicted neutral, anger-provoking (but race-neutral), and racist situations. Participants exhibited significantly greater diastolic blood pressure reactivity to anger-provoking and racist stimuli compared with neutral stimuli. In addition, high hostility was associated with higher recovery systolic and diastolic blood pressure levels after exposure to the films. Although the results failed to confirm previous reports of greater reactivity to racism in African Americans, the findings suggest that diastolic blood pressure levels may remain elevated after exposure to racist stimuli. These results indicate that even indirect exposure to interpersonal conflict elicits significant reactivity, which can persist after exposure to the stressor, especially among high-hostile men.

  18. Effects of acid-base imbalance on vascular reactivity

    A.C. Celotto

    2008-06-01

    Full Text Available Acid-base homeostasis maintains systemic arterial pH within a narrow range. Whereas the normal range of pH for clinical laboratories is 7.35-7.45, in vivo pH is maintained within a much narrower range. In clinical and experimental settings, blood pH can vary in response to respiratory or renal impairment. This altered pH promotes changes in vascular smooth muscle tone with impact on circulation and blood pressure control. Changes in pH can be divided into those occurring in the extracellular space (pHo and those occurring within the intracellular space (pHi, although, extracellular and intracellular compartments influence each other. Consistent with the multiple events involved in the changes in tone produced by altered pHo, including type of vascular bed, several factors and mechanisms, in addition to hydrogen ion concentration, have been suggested to be involved. The scientific literature has many reports concerning acid-base balance and endothelium function, but these concepts are not clear about acid-base disorders and their relations with the three known mechanisms of endothelium-dependent vascular reactivity: nitric oxide (NO/cGMP-dependent, prostacyclin (PGI2/cAMP-dependent and hyperpolarization. During the last decades, many studies have been published and have given rise to confronting data on acid-base disorder and endothelial function. Therefore, the main proposal of this review is to provide a critical analysis of the state of art and incentivate researchers to develop more studies about these issues.

  19. Electrochemical reactivity at graphitic micro-domains on polycrystalline boron doped diamond thin-films electrodes

    Mahe, E. [LI2C CNRS/UMR 7612, Laboratoire d' Electrochimie, Universite Pierre-et-Marie Curie - case courrier 51, 4, Place Jussieu, 75252 Paris Cedex 05 (France); Devilliers, D. [LI2C CNRS/UMR 7612, Laboratoire d' Electrochimie, Universite Pierre-et-Marie Curie - case courrier 51, 4, Place Jussieu, 75252 Paris Cedex 05 (France); Comninellis, Ch. [Unite de Genie Electrochimique, Institut de sciences des procedes chimiques et biologiques, Ecole Polytechnique Federale de Lausanne, 1015, Lausanne (Switzerland)

    2005-04-01

    This paper deals with the electrochemical reactivity of boron doped diamond (BDD) electrodes. A comparative study has been carried out to show the influence of the presence of graphitic micro-domains upon the surface of these films. Those graphitic domains are sometimes present on as-grown boron doped diamond electrodes. The effect of doping a pure Csp{sup 3} diamond electrode is established by highly oriented pyrolytic graphite (HOPG) abrasion onto the diamond surface. In order to establish the effect of doping on a pure Csp{sup 3} diamond electrode, the amount of graphitic domains was increased by means of HOPG crystals grafted onto the BDD surface. Indeed that method allows the enrichment of the Csp{sup 2} contribution of the electrode. The presence of graphitic domains can be correlatively associated with the presence of kinetically active redox sites. The electrochemical reactivity of boron doped diamond electrodes shows a distribution of kinetic constants on the whole surface of the electrode corresponding to different active sites. In this paper, we have studied by cyclic voltammetry and electrochemical impedance spectroscopy the kinetics parameters of the ferri/ferrocyanide redox couple in KCl electrolyte. A method is proposed to diagnose the presence of graphitic domains on diamond electrodes, and an electrochemical 'pulse cleaning' procedure is proposed to remove them.

  20. Electrochemical reactivity at graphitic micro-domains on polycrystalline boron doped diamond thin-films electrodes

    Mahe, E.; Devilliers, D.; Comninellis, Ch.

    2005-01-01

    This paper deals with the electrochemical reactivity of boron doped diamond (BDD) electrodes. A comparative study has been carried out to show the influence of the presence of graphitic micro-domains upon the surface of these films. Those graphitic domains are sometimes present on as-grown boron doped diamond electrodes. The effect of doping a pure Csp 3 diamond electrode is established by highly oriented pyrolytic graphite (HOPG) abrasion onto the diamond surface. In order to establish the effect of doping on a pure Csp 3 diamond electrode, the amount of graphitic domains was increased by means of HOPG crystals grafted onto the BDD surface. Indeed that method allows the enrichment of the Csp 2 contribution of the electrode. The presence of graphitic domains can be correlatively associated with the presence of kinetically active redox sites. The electrochemical reactivity of boron doped diamond electrodes shows a distribution of kinetic constants on the whole surface of the electrode corresponding to different active sites. In this paper, we have studied by cyclic voltammetry and electrochemical impedance spectroscopy the kinetics parameters of the ferri/ferrocyanide redox couple in KCl electrolyte. A method is proposed to diagnose the presence of graphitic domains on diamond electrodes, and an electrochemical 'pulse cleaning' procedure is proposed to remove them

  1. The effect of reactive emotions expressed in response to another's anger on inferences of social power.

    Hareli, Shlomo; David, Shlomo

    2017-06-01

    Social perception of emotions is influenced by the context in which it occurs. One such context is a social interaction involving an exchange of emotions. The way parties to the interaction are perceived is shaped by the combination of emotions exchanged. This idea was examined by assessing the extent to which expressions of anger toward a target-which, in isolation, are perceived as signals of high social power-are influenced by the target's emotional reaction to it (i.e., reactive emotions). Three studies show that the angry person was perceived as having a higher level of social power when this anger was responded by fear or sadness than when it was responded by neutrality or anger. Study 1 indicated that reactive emotions have a stronger effect on perceived social power when emotions were incongruent with gender stereotypes. Study 2 indicated that these effects are a result of these emotions serving as reactive emotions rather than a benchmark against which the angry person's power is assessed. Study 3 showed that reactive emotions affect perceived social power by serving as signals of the level to which the high social power suggested by the first person's expression is confirmed by its target. Comparing effects of reactive emotions to anger with reactive emotions to sadness, showed that perceived social power of the expresser is determined by the nature of the expression, with some adjustment caused by the reactive emotions. This underscores the importance of social interaction as a context for the social perception of emotions. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  2. Copper ferrocyanide - polyurethane foam as a composite ion exchanger for removal of radioactive cesium

    Rao, S.V.S.; Lal, K.B.; Ahmed, J.; Narasimhan, S.V.

    1999-01-01

    A method has been developed for the removal of cesium from the aqueous radioactive waste using a composite ion-exchanger consisting of Copper-Ferrocyanide Powder (CFC) and Polyurethane (PU) Foam. Polyvinyl acetate has been used as a binder in the preparation of CFC-PU foam. The physical properties of CFC such as density, surface area, IR stretching frequency and lattice parameters have been evaluated and also its potassium and copper(II) content have been estimated. Optimization of loading of CFC on PU foam has been studied. The CFC-PU was viewed under microscope to find out the homogeneity of distribution. Exchange capacities of the CFC-PU foam in different media have been determined and column studies have been carried out. Studies have been undertaken on extraction of cesium from CFC foam and also on digestion of spent CFC-PU foam and immobilization of digested solution in cement matrix. The cement matrices have been characterized with respect to density, bio-resistance and leaching resistance. (author)

  3. The effect of core configuration on temperature coefficient of reactivity in IRR-1

    Bettan, M.; Silverman, I.; Shapira, M.; Nagler, A. [Soreq Nuclear Research Center, Yavne (Israel)

    1997-08-01

    Experiments designed to measure the effect of coolant moderator temperature on core reactivity in an HEU swimming pool type reactor were performed. The moderator temperature coefficient of reactivity ({alpha}{sub {omega}}) was obtained and found to be different in two core loadings. The measured {alpha}{sub {omega}} of one core loading was {minus}13 pcm/{degrees}C at the temperature range of 23-30{degrees}C. This value of {alpha}{sub {omega}} is comparable to the data published by the IAEA. The {alpha}{sub {omega}} measured in the second core loading was found to be {minus}8 pcm/{degrees}C at the same temperature range. Another phenomenon considered in this study is core behavior during reactivity insertion transient. The results were compared to a core simulation using the Dynamic Simulator for Nuclear Power Plants. It was found that in the second core loading factors other than the moderator temperature influence the core reactivity more than expected. These effects proved to be extremely dependent on core configuration and may in certain core loadings render the reactor`s reactivity coefficient undesirable.

  4. The effect of polyamines on the photochemical reactivity of DNA

    Ben-Hur, E.; Hebrew Univ., Jerusalem

    1975-01-01

    The effects of diaminopentane (cadaverine), diaminoethane and the polyamine, spermine, on the photoreactions of 4,5', 8-trimethylpsoralen with DNA were studied. Near ultraviolet (UV) light (360 nm) irradiation of psoralen with DNA results in the formation of psoralen monoadducts with pyrimidine bases and DNA interstrand crosslinks. The polyamines studied reduced the rate of both photoreactions to the same extent by a factor of 1.5-2.0. The magnitude of the effect increased with polyamine concentration. Effectiveness was in the order spermine > cadaverine > diaminoethane. This is also the same order for stabilization of the DNA double-helix. Under conditions of higher DNA stability (higher ionic strength), higher polyamine concentrations were required to obtain an effect which was smaller than at low ionic strength. It is concluded that the photoreactions of psoralen with pyrimidines in DNA require some distortion of the double-helix. This distortion is made more difficult in the presence of stabilizing agents like polyamines and therefore the rate of the reaction is reduced. If crosslinking of DNA by psoralen is a two-step reaction then it must be concluded that the second step does not require further distortion. Consistently with the above, polyamines also reduced the UV-induced dimerization of thymine in DNA, although to a lesser extent. (author)

  5. Development of perturbation theory expressions for the evaluation of reactivity effects and sensitivity coefficient of reactivity effect to the group cross-sections on the basis of improved coarse mesh method for 3D diffusion problem

    Seregin, A.S.

    2000-01-01

    In the paper the formulae for perturbation theory functionals calculation are given and equations are based on improved coarse mesh discretization of diffusion problem in 3-dimensional geometry (Hex-Z). Expressions for the reactivity effect components and reactivity coefficients, written in the framework of the first order perturbation theory, are presented. On this basis the formulae for estimation of the sensitivity coefficients of different reactivity effects group cross-sections were derived. Expressions for the reactivity effect and its components obtained in the framework of the strict perturbation theory, are also presented in the paper. (author)

  6. Calculation code of heterogeneity effects for analysis of small sample reactivity worth

    Okajima, Shigeaki; Mukaiyama, Takehiko; Maeda, Akio.

    1988-03-01

    The discrepancy between experimental and calculated central reactivity worths has been one of the most significant interests for the analysis of fast reactor critical experiment. Two effects have been pointed out so as to be taken into account in the calculation as the possible cause of the discrepancy; one is the local heterogeneity effect which is associated with the measurement geometry, the other is the heterogeneity effect on the distribution of the intracell adjoint flux. In order to evaluate these effects in the analysis of FCA actinide sample reactivity worth the calculation code based on the collision probability method was developed. The code can handle the sample size effect which is one of the local heterogeneity effects and also the intracell adjoint heterogeneity effect. (author)

  7. Haematologic effect and Shwartzman reactivity of radiodetoxified endotoxin

    Szilagyi, T.; Csernyanszky, H.; Gazdy, E.; Bertok, L.

    1978-01-01

    Comparative experiments were made in rabbits with Escherichia coli 089 endotoxin and endotoxin detoxified by ionizing radiation ( 60 Co-gamma, 5 Mrad). Radiation significantly weakened the leukopenia and thrombocytopenia provoking effect of endotoxin. Radiodetoxified endotoxin decreased the fibrinogen level only slightly and caused insignificant changes in reptilase time. The complement level was decreased less by the detoxified than by the parent endotoxin. Even the local Shwartzman phenomenon inducing capacity of radiodetoxified endotoxin significantly, particularly when it was used for preparation and provocation, too. (author)

  8. Effects contributing to positive coolant void reactivity in CANDU

    Whitlock, J.J.; Garland, W.J.; Milgram, M.S.

    1995-01-01

    The lattice cell code WIMS-AECL (Ref. 3) is used to model a typical CANDU lattice cell, using nominal geometric bucklings, the PIJ option, and 69-group Winfrith library. The effect of cell voiding is modeled as a 100% instantaneous removal of coolant from the lattice. This is conservative because of the neglect of time dependence and partial core voiding, considered more plausible in CANDU. Results are grouped into three spectral groups: fast neutrons (0.821 to 10 MeV), epithermal neutrons (0.625 eV to 0.821 MeV), and thermal neutrons (<0.625 eV)

  9. Effect of reactive O+ implantation on the pearlite evolution

    Li Shuchen; Chen Yuanru; Radjabov, T.D.; Muchadadiev, R.E.; Zhang Pingyu; Liu Hong

    1993-01-01

    In the experiment the Fe-0.45wt%C alloy was implanted by Ar+, N+, and by Ar+, N+, O+ ions separately. Beneath the surface implanted by Ar+ and N+ an Auger peak of nitrogen is apparent. After implanting O+, however, the oxygen profile along the depth takes the Gaussian distribution and the nitrogen level is very low. TEM observation shows that the cementite laminae of the pearlite are distorted severely and even broken into rods or spheroid particles. The pearlite evolutions may be interpreted by the thermal spike effect of ion-implantation and preferential combination of C and O

  10. Haematologic effect and Shwartzman reactivity of radiodetoxified endotoxin

    Szilagyi, T; Csernyanszky, H; Gazdy, E [Debreceni Orvostudomanyi Egyetem (Hungary); Bertok, L [Orszagos Frederic Joliot-Curie Sugarbiologiai es Sugaregeszsegugyi Kutato Intezet, Budapest (Hungary)

    1978-01-01

    Comparative experiments were made in rabbits with Escherichia coli 089 endotoxin and endotoxin detoxified by ionizing radiation (/sup 60/Co-gamma, 5 Mrad). Radiation significantly weakened the leukopenia and thrombocytopenia provoking effect of endotoxin. Radiodetoxified endotoxin decreased the fibrinogen level only slightly and caused insignificant changes in reptilase time. The complement level was decreased less by the detoxified than by the parent endotoxin. Even the local Shwartzman phenomenon inducing capacity of radiodetoxified endotoxin significantly, particularly when it was used for preparation and provocation, too.

  11. Study on the effect of moderator density reactivity for Kartini reactor

    Budi Rohman; Widarto

    2009-01-01

    One of important characteristics of water-cooled reactors is the change of reactivity due to change in the density of coolant or moderator. This parameter generally has negative value and it has significant role in preventing the excursion of power during operation. Many thermal-hydraulic codes for nuclear reactors require this parameter as the input to account for reactivity feedback due to increase in moderator voids and the subsequent decrease in moderator density during operation. Kartini reactor is cooled and moderated by water, therefore, it is essential to study the effect of the change in moderator density as well as to determine the value of void or moderator density reactivity coefficient in order to characterize its behavior resulting from the presence of vapor or change of moderator density during operation. Analysis by MCNP code shows that the reactivity of core is decreasing with the decrease in moderator density. The analysis estimates the void or moderator density reactivity coefficient for Kartini Reactor to be -2.17×10-4 Δρ/ % void . (author)

  12. Episodic retrieval involves early and sustained effects of reactivating information from encoding.

    Johnson, Jeffrey D; Price, Mason H; Leiker, Emily K

    2015-02-01

    Several fMRI studies have shown a correspondence between the brain regions activated during encoding and retrieval, consistent with the view that memory retrieval involves hippocampally-mediated reinstatement of cortical activity. With the limited temporal resolution of fMRI, the precise timing of such reactivation is unclear, calling into question the functional significance of these effects. Whereas reactivation influencing retrieval should emerge with neural correlates of retrieval success, that signifying post-retrieval monitoring would trail retrieval. The present study employed EEG to provide a temporal landmark of retrieval success from which we could investigate the sub-trial time course of reactivation. Pattern-classification analyses revealed that early-onsetting reactivation differentiated the outcome of recognition-memory judgments and was associated with individual differences in behavioral accuracy, while reactivation was also evident in a sustained form later in the trial. The EEG findings suggest that, whereas prior fMRI findings could be interpreted as reflecting the contribution of reinstatement to retrieval success, they could also indicate the maintenance of episodic information in service of post-retrieval evaluation. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Effects of some structural materials on the reactivity and flux distributions in a pressurised water reactor

    Mondal, A.M.W.; Mannan, M.A.

    1983-01-01

    The effect of the structural materials of the guide tubes, spacer grids and the shroud on the reactivity and the flux distribution of a Pressurised Water Reactor (PWR) has been studied. Group constants of different cells of guide tubes, spacer grids, shroud and the fuel have been calculated using the cell codes LEOPARD, PANTHER and METHUSELAH. Core calculations have been performed using the diffusion code EQUIPOISE. It has been found for a PWR of 1300 MWe of Kraftwork Union design for Iron that the total change in reactivity due to the presence of guide tubes, spacer grids and the shroud is about -2.48x10 -2 . (author)

  14. Effect of reactivity insertion rate on peak power and temperatures in swimming pool type research reactor

    Khan, L.A.; Jabbar, A.; Anwar, A.R.; Ahmad, N.

    1998-01-01

    It is essential to study the reactor behavior under different accidental conditions and take proper measures for its safe operation. We have studied the effect of reactivity insertion, with and without scram conditions, on peak power and temperatures of fuel, cladding and coolant in typical swimming pool type research reactor. The reactivity ranging from 1 $ to 2 $ and insertion times from 0.25 to 1 second have been considered. The computer code PARET has been used and results are presented in this article. (author)

  15. Optimization of binary breeder reactor. 1. Sodium void reactivity and Doppler effect in a new model

    Nascimento, J.A. do; Dias, A.F.; Ishiguro, Y.

    1985-01-01

    A model for the Binary Breeder Reactor (BBR) is examined for the inherent safety characteristics, sodium void reactivity and Doppler effect in the beginning of cycle and a hypothetical end of cycle. In addition to the standard fueling mode of the BBR, two others are considered: U 238 /U 233 -alternate fueling, and U 238 /PU-normal fueling of LMFBRs. (Author) [pt

  16. Synergistic effect on co-gasification reactivity of biomass-petroleum coke blended char.

    Wei, Juntao; Guo, Qinghua; Gong, Yan; Ding, Lu; Yu, Guangsuo

    2017-06-01

    In this work, effects of gasification temperature (900°C-1100°C) and blended ratio (3:1, 1:1, 1:3) on reactivity of petroleum coke and biomass co-gasification were studied in TGA. Quantification analysis of active AAEM transformation and in situ investigation of morphological structure variations in gasification were conducted respectively using inductively coupled plasma optical emission spectrometer and heating stage microscope to explore synergistic effect on co-gasification reactivity. The results indicated that char gasification reactivity was enhanced with increasing biomass proportion and gasification temperature. Synergistic effect on co-gasification reactivity was presented after complete generation of biomass ash, and gradually weakened with increasing temperature from 1000°C to 1100°C after reaching the most significant value at 1000°C. This phenomenon was well related with the appearance of molten biomass ash rich in glassy state potassium and the weakest inhibition effect on active potassium transformation during co-gasification at the temperature higher than 1000°C. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Work-related social support modulates effects of early life stress on limbic reactivity during stress.

    Leicht-Deobald, Ulrich; Bruch, Heike; Bönke, Luisa; Stevense, Amie; Fan, Yan; Bajbouj, Malek; Grimm, Simone

    2017-12-15

    Early life stress (ELS) affects stress- reactivity via limbic brain regions implicated such as hippocampus and amygdala. Social support is a major protective factor against ELS effects, while subjects with ELS experience reportedly perceive less of it in their daily life. The workplace, where most adults spend a substantial amount of time in their daily lives, might serve as a major resource for social support. Since previous data demonstrated that social support attenuates stress reactivity, we here used a psychosocial stress task to test the hypothesis that work-related social support modulates the effects of ELS. Results show decreased amygdala reactivity during stress in ELS subjects who report high levels of work- related social support, thereby indicating a signature for reduced stress reactivity. However, this effect was only observable on the neural, but not on the behavioral level, since social support had no buffering effect regarding the subjective experience of stress in daily life as well as regarding feelings of uncontrollability induced by the stress task. Accordingly, our data suggest that subjects with ELS experiences might benefit from interventions targeted at lowering their subjective stress levels by helping them to better perceive the availability of social support in their daily lives.

  18. The Effect Of Beryllium Interaction With Fast Neutrons On the Reactivity Of ETRR-2 Research Reactor

    Aziz, M.; El Messiry, A.M.

    2000-01-01

    The effect of beryllium interactions with fast neutrons is studied for Etrr 2 research reactors. Isotope build up inside beryllium blocks is calculated under different irradiation times. a new model for the Etrr 2 research reactor is designed using MCNP code to calculate the reactivity and flux change of the reactor due to beryllium poison

  19. Cardiovascular reactivity in hypertensives: differential effect of expressing and inhibiting emotions during moments of interpersonal stress.

    Lipp, Marilda E Novaes; Pereira, Márcia M Bignotto; Justo, Ana Paula; de Matos, Thania M Gomes

    2006-11-01

    This study investigated cardiovascular reactivity of hypertensive adults during periods of emotional stress. Two types of instructions were given at different moments, to the same subject, either to express or to suppress feelings during role-play. Expressing, but not inhibiting, emotions elicited significantly higher reactivity during responding to negative scenes, followed by responding during the positive interactions. Blood pressure increases in both expressing and inhibiting conditions, were also found during the instruction periods. Results indicated that socially demanding situations represent a stressor whose effects may vary depending on whether or not respondents regulate expression of emotions. It is suggested that the difficulty in expressing emotions found in some hypertensive individuals may have the function of controlling or reducing blood pressure reactivity.

  20. Effect of mechanical activation on structure changes and reactivity in further chemical modification of lignin.

    Zhao, Xiaohong; Zhang, Yanjuan; Hu, Huayu; Huang, Zuqiang; Yang, Mei; Chen, Dong; Huang, Kai; Huang, Aimin; Qin, Xingzhen; Feng, Zhenfei

    2016-10-01

    Lignin was treated by mechanical activation (MA) in a customized stirring ball mill, and the structure and reactivity in further esterification were studied. The chemical structure and morphology of MA-treated lignin and the esterified products were analyzed by chemical analysis combined with UV/vis spectrometer, FTIR,NMR, SEM and particle size analyzer. The results showed that MA contributed to the increase of aliphatic hydroxyl, phenolic hydroxyl, carbonyl and carboxyl groups but the decrease of methoxyl groups. Moreover, MA led to the decrease of particle size and the increase of specific surface area and roughness of surface in lignin. The reactivity of lignin was enhanced significantly for the increase of hydroxyl content and the improvement of mass transfer in chemical reaction caused by the changes of molecular structure and morphological structure. The process of MA is green and simple, and is an effective method for enhancing the reactivity of lignin. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Effect of Anisotropy Structure on Plume Entropy and Reactive Mixing in Helical Flows

    Ye, Yu; Chiogna, Gabriele; Lu, Chunhui

    2018-01-01

    Plume dilution and reactive mixing can be considerably enhanced by helical flows occurring in three-dimensional anisotropic porous media. In this study, we perform conservative and reactive transport simulations considering different anisotropy structures of a single inclusion with the objective...... of exploring the effect of the inclusion’s geometry and orientation on the patterns of twisted streamlines and on the overall dilution and reaction of solute plumes. We analyzed 100 different scenarios by varying key parameters such as the angle of the anisotropic structures with respect to the average flow...... velocity, the spacing between alternated heterogeneous zones of coarse and fine materials, the permeability contrast between such matrices, and the magnitude of the seepage velocity. Entropy conservation equations and entropy-based metrics for both conservative and reactive species were adopted to quantify...

  2. Acute effects of tibolone on cerebral vascular reactivity in vitro

    Lund, C O; Nilas, Lisbeth; Dalsgaard, T

    2003-01-01

    alpha-OH-tibolone, 3beta-OH-tibolone, Delta(4) isomer and 17beta-estradiol were obtained before and after addition of the NO blocker N(omega)-nitro-L-arginine methyl ester (L-NAME, 10(-4) mol/l) or the potassium-channel blocker tetraethylammonium chloride (TEA, 10(-2) mol/l). Additionally, the effects...... of the hormones on the concentration-response curves with calcium were examined. RESULTS: Tibolone and its metabolites induced a concentration-dependent relaxation comparable to that of 17beta-estradiol (area under the curve (AUC); tibolone vs. 17beta-estradiol: 242 vs. 251; p ...-NAME increased the AUC for all substances compared with controls (p 17beta-estradiol. Preincubation with TEA induced no changes. The concentration-dependent contraction curves with calcium were shifted rightward by all hormones. CONCLUSIONS: The study demonstrates...

  3. Effects of poison panel shrinkage and gaps on fuel storage rack reactivity

    Boyd, W.A.; Mueller, D.E.

    1988-01-01

    Fixed poison panels are used in spent fuel rack designs to increase enrichment limits and reduce cell spacing; therefore, assurances that the maximum rack reactivity will meet the design limit (0.95) throughout the lifetime of the racks depend on the continued effectiveness of the poison with time. Industry data have shown that poison panels will shrink under irradiated conditions. From recent data, however, poison panels have been found to have gaps spanning their width after relatively short operating periods. This paper presents results of studies showing the fuel rack reactivity changes associated with poison panel shrinkage and formation of gaps. The discovery of gaps in the fuel rack poison panels at an operating plant raises concerns regarding the effectiveness of the poison over the lifetime of the fuel racks. Studies performed to evaluate the effect of the poison panel shrinkage on reactivity show that reactivity changes from zero to several percent are possible depending on the initial panel size. Results of recent studies show that some gaps can be accommodated in the fuel rack poison panels at the fuel midplane without causing the fuel rack K eff limit to be exceeded. With worst-case assumptions concerning gap size and the number of panels affected, other actions will likely be required to show that the rack K eff design limit will not be exceeded

  4. EFFECT OF REACTIVE MAGNESIUM OXIDE ON PROPERTIES OF ALKALI ACTIVATED SLAG GEOPOLYMER CEMENT PASTES

    H. A. Abdel-Gawwad

    2015-03-01

    Full Text Available The effect of different proportions and different reactivities of MgO on the drying shrinkage and compressive strength of alkali activated slag pastes (AAS has been investigated. The slag was activated by 6 wt.% sodium hydroxide and liquid sodium silicate at ratio of 3:3 (wt.. The different reactivities of MgOs were produced from the calcination of hydromagnesite at different temperatures (550, 1000, 1250 C. The results showed that the reactivity of magnesium oxide decreases with increasing the calcination temperature. Also, the drying shrinkage of AAS was reduced by the replacement of slag with MgOs. The highly reactive MgO accelerated the hydration of AAS at early ages. The replacement of slag with 5% MgO550 increased one day compressive strength by ~26 % while MgO1250 had little effect. A significant increase in strength was observed after 7 days in case of replacement of slag with 5 % MgO1250. The MgO reacts with slag to form hydrotalcite likephases (Ht as detected by XRD, FTIR spectroscopy, TGA/DTG analysis and SEM.

  5. Inherent safety that the reactivity effect of core bending in fast reactors brings about

    Nakagawa, Masatoshi; Yagawa, Genki.

    1994-01-01

    FBRs have the merit on safety by low operation pressure and the large heat capacity of coolant, in addition, due to the core temperature rise at the time of accidents and the thermal expansion of core structures, the negative feedback of reactivity can be expected. Recently, attention has been paid to the negative feedback of reactivity due to core bending. It can be expected also in the core of limited free bow type. Bending is caused by the difference of thermal expansion on six surfaces of hexagonal wrapper tubes. The bending changes core reactivity and exerts effects to fuel exchange force and operation, insertion of control rods and the structural soundness of fuel assemblies. for the purpose of limiting the effect that core bending exerts to core characteristics to allowable range, core constraint mechanism is installed. The behavior of core bending at the time of anticipated transient without scram is explained. The example of the analysis of PRISM reactor is shown. The experiment that confirmed the negative feedback of reactivity due to core bending under the condition of ULOF was that at the fast flux test facility. (K.I.)

  6. Ginseng and Ginkgo Biloba Effects on Cognition as Modulated by Cardiovascular Reactivity: A Randomised Trial.

    Derek Ong Lai Teik

    Full Text Available There is some evidence to suggest that ginseng and Ginkgo biloba can improve cognitive performance, however, very little is known about the mechanisms associated with such improvement. Here, we tested whether cardiovascular reactivity to a task is associated with cognitive improvement.Using a double-blind, placebo controlled, crossover design, participants (N = 24 received two doses of Panax Ginseng (500, 1000 mg or Ginkgo Biloba (120, 240 mg (N = 24, and underwent a series of cognitive tests while systolic, diastolic, and heart rate readings were taken. Ginkgo Biloba improved aspects of executive functioning (Stroop and Berg tasks in females but not in males. Ginseng had no effect on cognition. Ginkgo biloba in females reversed the initial (i.e. placebo increase in cardiovascular reactivity (systolic and diastolic readings increased compared to baseline to cognitive tasks. This effect (reversal was most notable after those tasks (Stroop and Iowa that elicited the greatest cardiovascular reactivity during placebo. In males, although ginkgo also decreased cardiovascular readings, it did so from an initial (placebo blunted response (i.e. decrease or no change from baseline to cognitive tasks. Ginseng, on the contrary, increased cardiovascular readings compared to placebo.These results suggest that cardiovascular reactivity may be a mechanism by which ginkgo but not ginseng, in females is associated with certain forms of cognitive improvement.ClinicalTrials.gov NCT02386852.

  7. Effects of nutritional supplementation on periodontal parameters, carotenoid antioxidant levels, and serum C-reactive protein.

    Harpenau, Lisa A; Cheema, Abida T; Zingale, Joseph A; Chambers, David W; Lundergan, William P

    2011-05-01

    Few studies have focused on the role of nutrition in periodontal disease. The purpose of this trial was to determine the effect of a nutritional supplement on gingival inflammation, bleeding, probing depth, clinical attachment level, carotenoid antioxidant level, and C-reactive protein. The test supplement, consisting of a standard multivitamin formula, as well as several phytonutrients associated with antiinflammatory/antioxidant effects, provided modest benefits in reducing inflammation; however, further studies with larger populations and longer intervention are warranted.

  8. Effect of tamoxifen on the coronary vascular reactivity of spontaneously hypertensive female rats

    M.V. Borgo

    2011-08-01

    Full Text Available Tamoxifen has been associated with a reduction in the incidence of myocardial infarction. However, the effects of tamoxifen on coronary reactivity have not been fully elucidated. The objective of this study was to determine the effects of chronic treatment with tamoxifen on coronary vascular reactivity in spontaneously hypertensive rats (SHR. Female SHR were divided into four groups (N = 7 each: sham-operated (SHAM, sham-operated and treated with tamoxifen (10 mg/kg by gavage for 90 days (TAMOX, ovariectomized (OVX, and ovariectomized and treated with tamoxifen (OVX+TAMOX. Mean arterial pressure (MAP, heart rate (HR, coronary perfusion pressure (CPP, and coronary vascular reactivity were measured. MAP and HR were reduced (9.42 and 11.67%, respectively in the OVX+TAMOX group compared to the OVX group (P < 0.01. The coronary vascular reactivity of the OVX+TAMOX group presented smaller vasoconstrictor responses to acetylcholine (2-64 µg when compared to the OVX group (P < 0.01 and this response was similar to that of the SHAM group. The adenosine-induced vasodilator response was greater in the TAMOX group compared to the SHAM and OVX groups (P < 0.05. Baseline CPP was higher in OVX+TAMOX and TAMOX groups (136 ± 3.6 and 130 ± 1.5 mmHg than in OVX and SHAM groups (96 ± 2 and 119 ± 2.3 mmHg; P < 0.01. Tamoxifen, when combined with OVX, attenuated the vasoconstriction induced by acetylcholine and increased the adenosine-induced vasodilatory response, as well as reducing the MAP, suggesting beneficial effects of tamoxifen therapy on coronary vascular reactivity after menopause.

  9. The Effects of Training Contingency Awareness During Attention Bias Modification on Learning and Stress Reactivity.

    Lazarov, Amit; Abend, Rany; Seidner, Shiran; Pine, Daniel S; Bar-Haim, Yair

    2017-09-01

    Current attention bias modification (ABM) procedures are designed to implicitly train attention away from threatening stimuli with the hope of reducing stress reactivity and anxiety symptoms. However, the mechanisms underlying effective ABM delivery are not well understood, with awareness of the training contingency suggested as one possible factor contributing to ABM efficacy. Here, 45 high-anxious participants were trained to divert attention away from threat in two ABM sessions. They were randomly assigned to one of three training protocols: an implicit protocol, comprising two standard implicit ABM training sessions; an explicit protocol, comprising two sessions with explicit instruction as to the attention training contingency; and an implicit-explicit protocol, in which participants were not informed of the training contingency in the first ABM session and informed of it at the start of the second session. We examined learning processes and stress reactivity following a stress-induction task. Results indicate that relative to implicit instructions, explicit instructions led to stronger learning during the first training session. Following rest, the explicit and implicit groups exhibited consolidation-related improvement in performance, whereas no such improvement was noted for the implicit-explicit group. Finally, although stress reactivity was reduced after training, contingency awareness did not yield a differential effect on stress reactivity measured using both self-reports and skin conductance, within and across sessions. These results suggest that explicit ABM administration leads to greater initial learning during the training protocol while not differing from standard implicit administration in terms of off-line learning and stress reactivity. Copyright © 2017. Published by Elsevier Ltd.

  10. Effects of direct injection timing and blending ratio on RCCI combustion with different low reactivity fuels

    Benajes, Jesús; Molina, Santiago; García, Antonio; Monsalve-Serrano, Javier

    2015-01-01

    Highlights: • E85 requires notable lower premixed energy ratios to achieve a stable combustion. • E10-95 leads to shorter and advanced combustion with higher maximum RoHR peaks. • E20-95, E10-98 and E10-95 reach EURO VI NOx and soot levels for all the engine loads. • E10-95 allows a significant reduction in HC and CO emissions. - Abstract: This work investigates the effects of the direct injection timing and blending ratio on RCCI performance and engine-out emissions at different engine loads using four low reactivity fuels: E10-95, E10-98, E20-95 and E85 (port fuel injected) and keeping constant the same high reactivity fuel: diesel B7 (direct injected). The experiments were conducted using a heavy-duty single-cylinder research diesel engine adapted for dual-fuel operation. All the tests were carried out at 1200 rpm. To assess the blending ratio effect, the total energy delivered to the cylinder coming from the low reactivity fuel was kept constant for the different fuel blends investigated by adjusting the low reactivity fuel mass as required in each case. In addition, a detailed analysis of the air/fuel mixing process has been developed by means of a 1-D in-house developed spray model. Results suggest that notable higher diesel amount is required to achieve a stable combustion using E85. This fact leads to higher NOx levels and unacceptable ringing intensity. By contrast, EURO VI NOx and soot levels are fulfilled with E20-95, E10-98 and E10-95. Finally, the higher reactivity of E10-95 results in a significant reduction in CO and HC emissions, mainly at low load

  11. Effect of 3-D moderator flow configurations on the reactivity of CANDU nuclear reactors

    Zadeh, Foad Mehdi; Etienne, Stephane; Chambon, Richard; Marleau, Guy; Teyssedou, Alberto

    2017-01-01

    Highlights: • 3-D CFD simulations of CANDU-6 moderator flows are presented. • A thermal-hydraulic code using thermal physical fluid properties is used. • The numerical approach and convergence is validated against available data. • Flow configurations are correlated using Richardson’s number. • The interaction between moderator temperatures with reactivity is determined. - Abstract: The reactivity of nuclear reactors can be affected by thermal conditions prevailing within the moderator. In CANDU reactors, the moderator and the coolant are mechanically separated but not necessarily thermally isolated. Hence, any variation of moderator flow properties may change the reactivity. Until now, nuclear reactor calculations have been performed by assuming uniform moderator flow temperature distribution. However, CFD simulations have predicted large time dependent flow fluctuations taking place inside the calandria, which can bring about local temperature variations that can exceed 50 °C. This paper presents robust CANDU 3-D CFD moderator simulations coupled to neutronic calculations. The proposed methodology makes it possible to study not only different moderator flow configurations but also their effects on the reactor reactivity coefficient.

  12. Ion exchange studies with ferrocyanide molybdate and zirconium phosphate in mixed solvent media. Part 1: Synthesis of the exchangers

    Ramaswamy, M.; Sunder Rajan, N.S.

    1979-01-01

    The present research forms the first part of the series on the investigation of the ion exchange behaviour of ferrocyanide molybdate(FeMo) and zirconium phosphate(ZrP) in water-alcohol and water-dioxane media. Since the above exchangers are not available indigenously, they were synthesized following published methods. That the reported methods of synthesis yield products with reproducible characteristics, were checked. pH titration of these two preparations in aqueous media showed that FeMo is a stronger acid than ZrP, the former, moreover, in its Cs + and Na + forms commence dissolving at pH values close to 5 and 2 respectively, and are completely dissolved at pH values 7.5 and 2.85 respectively. Titration curves with ZrP further indicated that as the pH increases, there occurs a reversal in the order of arrangement of Na + and Cs + curves, which reversal is attributed to a corresponding reversal of selectivity. Finally, both the chemical analysis and pH titration of FeMo confirm the existence of 4 replaceable H + ions corresponding to H 4 Fe(CN) 6 , a constituent of ferrocyanide molybdate, while those of ZrP are consistent with the empirical formula Zr(HPO 4 ) 2 .4.5 H 2 O, having two replaceable H + ions. (auth.)

  13. Efficient biodegradation of cyanide and ferrocyanide by Na-alginate beads immobilized with fungal cells of Trichoderma koningii.

    Zhou, Xiaoying; Liu, Lixing; Chen, Yunpeng; Xu, Shufa; Chen, Jie

    2007-09-01

    Cyanide or metal cyanide contaminations have become serious environmental and food-health problems. A fungal mutant of Trichoderma koningii, TkA8, constructed by restriction enzyme-mediated integration, has been verified to have a high cyanide degradation ability in our previous study. In this study, the mutant cells were entrapped in sodium-alginate (Na-alginate) immobilization beads to degrade cyanide and ferrocyanide in a liquid mineral medium. The results showed that the fungus in immobilization beads consisting of 3% Na-alginate and 3% CaCl2 could degrade cyanide more efficiently than a nonimmobilized fungal culture. For maximum degradation efficiency, the optimal ratio of Na-alginate and wet fungal biomass was 20:1 (m/m) and the initial pH was 6.5. In comparison, cell immobilization took at least 3 and 8 days earlier, respectively, to completely degrade cyanide and ferrocyanide. In addition, we showed that the immobilized beads could be easily recovered from the medium and reused for up to 5 batches without significant losses of fungal remediation abilities. The results of this study provide a promising alternative method for the large-scale remediation of soil or water systems from cyanide contamination.

  14. The Effect of Aging on the Dynamics of Reactive and Proactive Cognitive Control of Response Interference.

    Xiang, Ling; Zhang, Baoqiang; Wang, Baoxi; Jiang, Jun; Zhang, Fenghua; Hu, Zhujing

    2016-01-01

    A prime-target interference task was used to investigate the effects of cognitive aging on reactive and proactive control after eliminating frequency confounds and feature repetitions from the cognitive control measures. We used distributional analyses to explore the dynamics of the two control functions by distinguishing the strength of incorrect response capture and the efficiency of suppression control. For reactive control, within-trial conflict control and between-trial conflict adaption were analyzed. The statistical analysis showed that there were no reliable between-trial conflict adaption effects for either young or older adults. For within-trial conflict control, the results revealed that older adults showed larger interference effects on mean RT and mean accuracy. Distributional analyses showed that the decline mainly stemmed from inefficient suppression rather than from stronger incorrect responses. For proactive control, older adults showed comparable proactive conflict resolution to young adults on mean RT and mean accuracy. Distributional analyses showed that older adults were as effective as younger adults in adjusting their responses based on congruency proportion information to minimize automatic response capture and actively suppress the direct response activation. The results suggest that older adults were less proficient at suppressing interference after conflict was detected but can anticipate and prevent inference in response to congruency proportion manipulation. These results challenge earlier views that older adults have selective deficits in proactive control but intact reactive control.

  15. The effect of aging on the dynamics of reactive and proactive cognitive control of response interference

    Ling Xiang

    2016-11-01

    Full Text Available A prime-target interference task was used to investigate the effects of cognitive aging on reactive and proactive control in which frequency confounds and feature repetitions were eliminated from the cognitive control measures. We used distributional analyses to explore the dynamics of the two control functions by distinguishing the strength of incorrect response capture and the efficiency of suppression control. For reactive control, within-trial conflict control and between-trial conflict adaption were analyzed. The statistical analysis showed that there were no reliable between-trial conflict adaption effects for both young and older adults. For within-trial conflict control, the results revealed that older adults showed larger interference effects on mean RT and mean accuracy. Distributional analyses showed that the decline mainly stemmed from inefficient suppression rather than from stronger incorrect responses. For proactive control, older adults showed comparable proactive conflict resolution than young adults on mean RT and mean accuracy. Distributional analyses showed older adults were as effective as younger adults in adjusting their responses to minimize automatic response capture and actively suppress the direct response activation based on congruency proportion information. The results suggest that older adults were less proficient at suppressing interference after conflict was detected but can anticipate and prevent inference in response to congruency proportion manipulation. The results challenge earlier views that older adults have selective deficits in proactive control but are spared in reactive control.

  16. Reactivity effect of spent fuel depending on burn-up history

    Hayashi, Takafumi; Suyama, Kenya; Nomura, Yasushi

    2001-06-01

    It is well known that a composition of spent fuel depends on various parameter changes throughout a burn-up period. In this study we aimed at the boron concentration and its change, the coolant temperature and its spatial distribution, the specific power, the operation mode, and the duration of inspection, because the effects due to these parameters have not been analyzed in detail. The composition changes of spent fuel were calculated by using the burn-up code SWAT, when the parameters mentioned above varied in the range of actual variations. Moreover, to estimate the reactivity effect caused by the composition changes, the criticality calculations for an infinite array of spent fuel were carried out with computer codes SRAC95 or MVP. In this report the reactivity effects were arranged from the viewpoint of what parameters gave more positive reactivity effect. The results obtained through this study are useful to choose the burn-up calculation model when we take account of the burn-up credit in the spent fuel management. (author)

  17. Study of catalytic effects of mineral matter level on coal reactivity

    Mazzocco, Nestor J.; Klunder, Edgar B.; Krastman, Donald

    1981-03-01

    Coal liquefaction experiments using a 400-lb/day bubble-column reactor tested the catalytic effects of added mineral matter level on coal conversion, desulfurization, and distillate yields in continuous operation under recycle conditions, with specific emphasis on the use of a disposable pyrite catalyst indigenous to the feed coal. Western Kentucky No. 11 run-of-mine (ROM) and washed coals were used as feedstocks to determine the effects of levels of mineral matter, specifically iron compounds. Liquefaction reactivity as characterized by total distillate yield was lower for washed coal, which contained less mineral matter. Liquefaction reactivity was regained when pyrite concentrate was added as a disposable catalyst to the washed coal feed in sufficient quantity to match the feed iron concentration of the run-of-mine coal liquefaction test run.

  18. Preparation of ferrocyanide molybdate and their selective uptake properties for palladium and cesium ions

    Hitoshi, Mimura; Ayumi, Asakura; Yan, Wu; Yuichi, Niibori; Masaki, Ozawa [Tohoku Univ., Dept. of Quantum Science and Engineering Graduate School of Engineering (Japan)

    2007-07-01

    The selective separation of heat-generating nuclide (Cs) and platinum group metal (Pd) containing in high-level liquid wastes (HLLW) is an important subject for the advancement of nuclear fuel cycle. Selective uptake of these nuclides was accomplished by using insoluble ferrocyanide molybdates (FeMo-[1-4]). The uptake properties of Pd{sup 2+} and Cs{sup +} for MoFe-[1-4] in the presence of 1 M HNO{sub 3} were examined by batch method. Relatively high uptake percentages of Pd{sup 2+} and Cs{sup +} above 90% were obtained within 30 min. The uptake percentage above 90% was kept in the presence of 0.1-3 M HNO{sub 3}. The uptake selectivity of Pd{sup 2+} was higher than that of Cs{sup +}; the separation factor of Pd{sup 2+} to Cs{sup +} increased with coexisting HNO{sub 3} concentration and was estimated to be 15 at 3 M HNO{sub 3}. The uptake of Pd{sup 2+} and Cs{sup +} on FeMo-[1-4] followed a Langmuir-type adsorption equation, and the uptake capacities of Pd{sup 2+} and Cs{sup +} were estimated to be [0.17-0.28] and [1.68-2.24] mmol/g, respectively. The uptake is mainly governed by the ion-exchange reaction between exchangeable cations (Na{sup +} and K{sup +}) and target cations (Pd{sup 2+} and Cs{sup +}). Further, the selective uptake of Pd{sup 2+} and Cs{sup +} was confirmed by using simulated HLLW (28 components, SW-11, JAEA); the uptake equilibrium attained within 30 min and the uptake percentages of Pd{sup 2+} and Cs{sup +} were 99 and 85 %, respectively. In order to granulate the fine powders of FeMo exchangers, the alginate gel polymer was used as an immobilizing matrix for the micro-encapsulation. The uptake percentages of Pd{sup 2+} and Cs{sup +} for FeMo-3 micro-capsule were above 80% even in the presence of 3 M HNO{sub 3}. Thus the molybdate can be converted to the ion-exchanger having high selectivity towards Pd{sup 2+} and Cs{sup +} in HLLW. This conversion method leads to the volume reduction of wastes and the utilization of useful nuclides. (authors)

  19. Effects of drying methods on the low temperature reactivity of Victorian brown coal to oxygen

    Unal, S.; Wood, D.G.; Harris, I.J. (University of Marmara, Istanbul (Turkey). Ataturk Faculty of Education, Division of Science Education)

    1992-02-01

    The effects of air drying and thermal dewatering on the low temperature oxygen reactivity of Victorian brown coal have been investigated in the temperature range 35-55{degree}C and at 100 kPa oxygen pressure using coal samples ground to {lt} 100 mesh. An attempt has also been made to relate the low temperature oxygen reactivity of the coal to its free radical concentration as measured prior to oxidation. Two rate models, the Schmidt and Winmill models, have been adapted to include the initial free radical concentration of the coal samples as the drying method sensitivity parameter in lieu of the concentration of oxygen-reactive sites in the coal material. The experimental results show that air drying, which reduces the free radical concentration of the coal, causes a decline in its oxygen reactivity whereas thermal dewatering, which causes an increase in the free radical concentration of the coal, enhances its oxygen reactivity. Air drying does not affect the distribution of the consumed oxygen in the oxidation products. A difference is observed in the case of the thermally dewatered coal samples. The correlation of the two rate models adopted is considered equally satisfactory. However, only the values obtained for the two activation energies in the Winmill model reflect the changes caused by thermal dewatering in the oxidation pattern of the coal. The activation energy values obtained from the two models are within the range of those quoted in the literature for the abstraction of hydrogen from various arene structures by free radicals. 35 refs., 10 figs., 8 tabs.

  20. Effective biotransformation and detoxification of anthraquinone dye reactive blue 4 by using aerobic bacterial granules.

    Chaudhari, Ashvini U; Paul, Dhiraj; Dhotre, Dhiraj; Kodam, Kisan M

    2017-10-01

    Treatment of textile wastewater containing anthraquinone dye is quite a huge challenge due to its complex aromatic structure and toxicity. Present study deals with the degradation and detoxification of anthraquinone dye reactive blue 4 using aerobic bacterial granules. Bacterial granules effectively decolorized reactive blue 4 at wide range of pH (4.0-11.0) and temperature (20-55 °C) as well as decolorized and tolerated high concentration of reactive blue 4 dye upto 1000 mg l -1 with V max 6.16 ± 0.82 mg l -1 h -1 and K m 227 ± 41 mg l -1 . Metagenomics study evaluates important role of Clostridia, Actinobacteria, and Proteobacterial members in biotransformation and tolerance of high concentrations of reactive blue 4 dye. Up-regulation of xenobiotic degradation and environmental information processing pathways during dye exposure signifies their noteworthy role in dye degradation. Biotransformation of dye was confirmed by significant decrease in the values of total suspended solids, biological and chemical oxygen demand. The metabolites formed after biotransformation was characterized by FT-IR and GC-MS analysis. The reactive blue 4 dye was found to be phytotoxic, cytotoxic and genotoxic whereas its biotransformed product were non-toxic. This study comprehensively illustrates that, bacterial aerobic granules can be used for eco-friendly remediation and detoxification of wastewater containing high organic load of anthraquinone dye. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Effects of intermittent theta burst stimulation on cerebral blood flow and cerebral vasomotor reactivity.

    Pichiorri, Floriana; Vicenzini, Edoardo; Gilio, Francesca; Giacomelli, Elena; Frasca, Vittorio; Cambieri, Chiara; Ceccanti, Marco; Di Piero, Vittorio; Inghilleri, Maurizio

    2012-08-01

    To determine whether intermittent theta burst stimulation influences cerebral hemodynamics, we investigated changes induced by intermittent theta burst stimulation on the middle cerebral artery cerebral blood flow velocity and vasomotor reactivity to carbon dioxide (CO(2)) in healthy participants. The middle cerebral artery flow velocity and vasomotor reactivity were monitored by continuous transcranial Doppler sonography. Changes in cortical excitability were tested by transcranial magnetic stimulation. In 11 healthy participants, before and immediately after delivering intermittent theta burst stimulation, we tested cortical excitability measured by the resting motor threshold and motor evoked potential amplitude over the stimulated hemisphere and vasomotor reactivity to CO(2) bilaterally. The blood flow velocity was monitored in both middle cerebral arteries throughout the experimental session. In a separate session, we tested the effects of sham stimulation under the same experimental conditions. Whereas the resting motor threshold remained unchanged before and after stimulation, motor evoked potential amplitudes increased significantly (P = .04). During and after stimulation, middle cerebral artery blood flow velocities also remained bilaterally unchanged, whereas vasomotor reactivity to CO(2) increased bilaterally (P = .04). The sham stimulation left all variables unchanged. The expected intermittent theta burst stimulation-induced changes in cortical excitability were not accompanied by changes in cerebral blood flow velocities; however, the bilateral increased vasomotor reactivity suggests that intermittent theta burst stimulation influences the cerebral microcirculation, possibly involving subcortical structures. These findings provide useful information on hemodynamic phenomena accompanying intermittent theta burst stimulation, which should be considered in research aimed at developing this noninvasive, low-intensity stimulation technique for safe

  2. The effects of trait impulsivity on proactive and reactive interference control.

    Xiang, Ling; Chen, Yan; Chen, Antao; Zhang, Fenghua; Xu, Fuming; Wang, Baoxi

    2018-02-01

    The current study used event-related brain potentials (ERPs) to explore whether self-reported trait impulsivity in healthy individuals might be differentially related to proactive and reactive interference control. Participants with high and low impulsivity (HI and LI, respectively) performed a modified version of the prime-target interference task. Proactive interference control was induced in the mostly incongruent (MI) context and reactive interference control was induced in the mostly congruent (MC) context. Although the behavioral data revealed no difference between HI and LI individuals in terms of the interference effects (incongruent - congruent) under both contexts, the ERP results showed that impulsivity has a different influence on the interference effects under different task contexts. In the MC context, the interference effects on the medial frontal negativity (MFN) and the negative sustained potential (N-SP) were greater, while that on the positive sustained potential (P-SP) were smaller in the HI compared to those in the LI group. This suggests that high levels of impulsivity might be associated with a reduced efficiency of the processes supporting reactive control to resolve interference when interference is not expected. In contrast, the three ERP indices (MFN, P-SP, and N-SP) of interference processing in the MI context were insensitive to variations in impulsivity. This suggests that HI individuals might be as effective as LI individuals in recruiting proactive control for sustained active maintenance of task goals to anticipate and prevent interference throughout the experimental blocks where interference occurs frequently. In conclusion, these results indicate that impulsivity has a more negative influence on reactive interference control than on proactive interference control. Copyright © 2017. Published by Elsevier B.V.

  3. Effects of moderation level on core reactivity and. neutron fluxes in natural uranium fueled and heavy water moderated reactors

    Khan, M.J.; Aslam; Ahmad, N.; Ahmed, R.; Ahmad, S.I.

    2005-01-01

    The neutron moderation level in a nuclear reactor has a strong influence on core multiplication, reactivity control, fuel burnup, neutron fluxes etc. In the study presented in this article, the effects of neutron moderation level on core reactivity and neutron fluxes in a typical heavy water moderated nuclear research reactor is explored and the results are discussed. (author)

  4. Biological Sensitivity to Context: The Interactive Effects of Stress Reactivity and Family Adversity on Socioemotional Behavior and School Readiness

    Obradovic, Jelena; Bush, Nicole R.; Stamperdahl, Juliet; Adler, Nancy E.; Boyce, W. Thomas

    2010-01-01

    This study examined the direct and interactive effects of stress reactivity and family adversity on socioemotional and cognitive development in three hundred and thirty-eight 5- to 6-year-old children. Neurobiological stress reactivity was measured as respiratory sinus arrhythmia and salivary cortisol responses to social, cognitive, sensory, and…

  5. Social support and loneliness in college students: effects on pulse pressure reactivity to acute stress.

    O'Donovan, Aoife; Hughes, Brian

    2007-01-01

    Socially supportive relationships at university may buffer against psychological stress in students, particularly in those experiencing loneliness. To examine the relation of social support at university and loneliness with pulse pressure (PP) reactivity to acute psychological stress in a sample of first-year undergraduate students. Sixty-five female, adolescent, first-year university students. Pulse pressure (PP) was calculated as the arithmetic difference between systolic blood pressure and diastolic blood pressure, which were measured during a resting baseline and during a stressful reading task. The difference between baseline and reading task PP represents PP reactivity. The Social Support at University Scale (SSUS) was used to assess social support availability in university, and the Revised UCLA Loneliness Scale was used to assess loneliness. Hierarchical linear regression was used to examine main and interactive effects of SSUS and loneliness on PP change scores, and simple slopes were computed to assist in the interpretation of interaction effects. Social support at university was associated with lower PP reactivity in students reporting medium (t = -2.03, p = .04) or high levels of loneliness (t = -2.93, p = .004), but not in those reporting low levels of loneliness (t = -0.20, p = .83). Psychosocial interventions designed to increase social support available at university, and targeted at students experiencing loneliness may buffer against the harmful effects of acute stressors in lonely first-year students.

  6. Effectiveness of Chinese Martial Arts and Philosophy to Reduce Reactive and Proactive Aggression in Schoolchildren.

    Fung, Annis Lai Chu; Lee, Toney Ka Hung

    2018-04-10

    This study examined the effectiveness of Chinese martial arts in reducing reactive and proactive aggressive behavior among schoolchildren with a cluster-randomized trial. A screening questionnaire was completed by 3511 schoolchildren of Grades 2 to 5 from 13 sites in Hong Kong. We shortlisted 298 children who scored z ≥ 1 on the total score of the Reactive-Proactive Aggression Questionnaire in their respective sites to participate in the experiment. They were divided into 31 clusters that were blinded and randomly assigned to one of the 4 conditions: skills only, philosophy only, skills and philosophy, and physical fitness (placebo). Subjects were assessed at baseline, posttraining, and 6 months after training using aggression scales. Results from the linear mixed model indicated that the time × training interaction effects were significant for aggressive behavior (reactive and proactive), delinquent behavior, anxiety/depression, and attention problems. Although all measures declined in all conditions over time, only the skills-and-philosophy condition showed a significant reduction at posttraining and/or 6-month follow-up compared with the placebo. The results provided a theoretical proof for the relationship between aggression and sport involvement combined with children's moral reasoning. This study gives practical implications to intervention that solely playing sports or teaching moral lessons is not effective enough for high-risk schoolchildren with aggressive behavior. However, combined traditional Chinese martial arts skills and moral philosophy training could be considered in the school curriculum to reduce school violence and facilitate creation of harmonious schools.

  7. Effect of reactive and un-reactive substrates on photopolymerization of self-etching adhesives with different aggressiveness.

    Zhang, Ying; Wang, Yong

    2013-01-01

    The study investigated the influence of reactive (enamel) and un-reactive (glass) substrates on photo-polymerization of self-etching adhesives. Two commercial adhesives Adper Prompt L-Pop (APLP, pH~0.8) and Adper Easy Bond (AEB, pH~2.5) were applied onto prepared enamel and glass substrates using the same protocol. Micro-Raman spectroscopy was employed to determine the degree of conversion (DC) and the involved mechanism. DC of APLP was dramatically enhanced from ~9.4% to ~82.0% as when changing from glass to enamel, while DC of AEB on both substrates showed no difference. The DC distributions along the adhesive layers of the APLP and AEB on enamel showed descending and constant trends, respectively. Spectral analysis disclosed that the difference in chemical reaction of the two adhesives with enamel might be associated with the results. The chemical reaction of the adhesives with enamel significantly improved the DC of the strong APLP, but not that of the mild AEB.

  8. Dependence of ferrocyanide preparation Bifezh efficiency on age peculiarities of cattle.; Zavisimost` ehffektivnosti ferrotsianidnogo preparata Bifezh ot vozrastnykh osobennostej krupnogo rogatogo skota.

    Gashchak, S P; Burov, N I; Arkhipov, N P [Nauchno-Proizvodstvennoe Ob` ` edinenie Pripyat` , Chernobyl (Ukraine)

    1994-12-31

    The aim of the experiment on cattle feeding a ration with high contents of {sup 137} Cs was to estimate an influence of age peculiarities on efficiency of ferrocyanide preparation Bifezh (a food additive). Data testifying to a decrease of the preparation efficiency with the age of calves are obtained. A sum of factors determining this regularity is analyzed.

  9. Effect of processing temperature on the bitumen/MDI-PEG reactivity

    Martin-Alfonso, M.J.; Partal, P.; Navarro, F.J.; Garcia-Morales, M. [Departamento de Ingenieria Quimica, Facultad de Ciencias Experimentales, Campus de ' El Carmen' , Universidad de Huelva, 21071, Huelva (Spain); Bordado, J.C.M. [Chemical and Biological Engineering Department, IBB, Instituto Superior Tecnico, Av. Rovisco Pais 1049-001 Lisbon (Portugal); Diogo, A.C. [Materials Engineering Department, Instituto Superior Tecnico, Av. Rovisco Pais 1049-001 Lisbon (Portugal)

    2009-04-15

    Reactive polymers are lately gaining acceptance to give added value to a residue of the crude oil refining process such as bitumen. The resulting material should display enhanced mechanical properties to be considered for advanced applications in construction. In the present paper, we report the effect of processing temperature on the reaction between bitumen compounds and an isocyanate-based reactive polymer, synthesized by reaction of polymeric MDI (4,4'-diphenylmethane diisocyanate) with a low molecular weight polyethylene-glycol (PEG). Rheokinetics experiments, viscosity measurements at 60 C, atomic force microscopy (AFM) characterization, thin layer chromatography (TLC-FID) analysis and thermogravimetric studies (TGA) were performed on the reactive polymer and on samples of MDI-PEG modified bitumen containing 2 wt.% of the polymer. Results showed the existence of an optimum processing temperature arisen as a consequence of opposite effects: microstructural availability for the formation of a polymer-bitumen network, reaction ability and polymer thermal degradation. Consequently, this study aims to serve as a guideline for the refining and asphalt industries facing the stage of selecting the optimum processing parameters. (author)

  10. Influence of void effects on reactivity of coupled fast-thermal system HERBE

    Ljubenov, V.; Milovanovic, S.; Milovanovic, T.; Cuknic, O.

    1997-01-01

    Coupled fast-thermal system HERBE at the experimental zero power heavy water reactor RB is a system with the significant effects of the neutron leakage and neutron absorption. Presence of a coolant void introduces a new structure in an extremely heterogeneous core. In those conditions satisfactory results of the calculation are acquired only using specified space-energy homogenization procedure. In order to analyze transient appearances and accidental cases of the reactor systems, a procedure for modeling of influence of moderator and coolant loss on reactivity ('void effect') is developed. Reduction of the moderator volume fraction in some fuel channels due to air gaps or steam generation during the accidental moderator boiling, restricts validity of the diffusion approximation in the reactor calculations. In cases of high neutron flux gradients, which are consequence of high neutron absorption, application of diffusion approximation is questionable too. The problem may be solved using transport or Monte Carlo methods, but they are not acceptable in the routine applications. Applying new techniques based on space-energy core homogenization, such as the SPH method or the discontinuity factor method, diffusion calculations become acceptable. Calculations based on the described model show that loss of part of moderator medium introduce negative reactivity in the HERBE system. Calculated local void reactivity coefficients are used in safety analysis of hypothetical accidents

  11. Studies of the Reactivity Effect of Polythene in the Fast Reactor FR0

    Tiren, I; Haakansson, R

    1967-12-15

    Measurements of the reactivity effect of polythene (CH{sub 2}){sub n} have been made in two FR0 assemblies having neutron spectra broadly similar to those of current steam cooled fast reactor concepts. The experiments include studies of the axial and radial distributions of the reactivity coefficient. The reactivity contributions from small polythene samples were found to be approximately additive. No large effects of heterogeneity or interaction between samples were observed. Comparisons with calculations using a homogeneous model are therefore relevant. The experimental results are largely in reasonable agreement with calculated values. The latter are very sensitive to moderate changes in the cross sections at low neutron energies. The agreement with experiment is improved if transport rather than diffusion theory is used. Although the geometrical size of FR0 is probably adequate for studies of steam coefficients in fast power reactors, Pu isotopes and fission products should be included in the core composition in order to obtain information of direct use in such studies.

  12. Effects of a prevention program for divorced families on youth cortisol reactivity 15 years later.

    Luecken, Linda J; Hagan, Melissa J; Mahrer, Nicole E; Wolchik, Sharlene A; Sandler, Irwin N; Tein, Jenn-Yun

    2015-01-01

    We examined whether an empirically based, randomised controlled trial of a preventive intervention for divorced mothers and children had a long-term impact on offspring cortisol regulation. Divorced mothers and children (age 9-12) were randomly assigned to a literature control condition or the 11-week New Beginnings Program, a family-focused group preventive intervention for mothers and children in newly divorced families. Fifteen years after the trial, offspring salivary cortisol (n = 161) was measured before and after a social stress task. Multilevel mixed models were used to predict cortisol from internalizing symptoms, externalizing symptoms, group assignment and potential moderators of intervention effects. Across the sample, higher externalizing symptoms were associated with lower cortisol reactivity. There was a significant group-by-age interaction such that older offspring in the control group had higher reactivity relative to the intervention group, and younger offspring in the control group exhibited a decline across the task relative to younger offspring in the intervention group. Preventive interventions for youth from divorced families may have a long-term impact on cortisol reactivity to stress. Results highlight the importance of examining moderators of program effects.

  13. Stressful life events and depression symptoms: the effect of childhood emotional abuse on stress reactivity.

    Shapero, Benjamin G; Black, Shimrit K; Liu, Richard T; Klugman, Joshua; Bender, Rachel E; Abramson, Lyn Y; Alloy, Lauren B

    2014-03-01

    Stressful life events are associated with an increase in depressive symptoms and the onset of major depression. Importantly, research has shown that the role of stress changes over the course of depression. The present study extends the current literature by examining the effects of early life stress on emotional reactivity to current stressors. In a multiwave study (N = 281, mean age = 18.76; 68% female), we investigated the proximal changes that occur in depressive symptoms when individuals are faced with life stress and whether a history of childhood emotional abuse moderates this relationship. Results support the stress sensitivity hypothesis for early emotional abuse history. Individuals with greater childhood emotional abuse severity experienced greater increases in depressive symptoms when confronted with current dependent stressors, controlling for childhood physical and sexual abuse. This study highlights the importance of emotional abuse as an indicator for reactivity to stressful life events. © 2013 Wiley Periodicals, Inc.

  14. Relations of children's proactive and reactive assertiveness to peer acceptance: moderating effects of social interest.

    Lee, Han-Jong

    2014-06-01

    Previous studies on the social outcome of assertiveness reported mixed findings, failing to support the assumption that assertiveness promotes peer acceptance. In an attempt to provide explanations for the inconsistencies in prior findings, this study proposed making a distinction between proactive and reactive assertiveness and examined the moderating effects of social interest. A total of 441 fifth and sixth graders (232 boys, 209 girls; M age = 10.6 yr., SD = 0.6) participated in the study. Results indicated that proactive assertiveness was positively related to peer acceptance regardless of social interest. By contrast, reactive assertiveness was positively related to peer acceptance but only when social interest is high. When social interest is low, it was negatively associated with peer acceptance.

  15. Long term storage effects of irradiated fuel elements on power distribution and reactivity

    Ponzoni Filho, P.; Sato, Sadakatu; Santos, Teresinha Ipojuca Cardoso T.I.C.; Fernandes Vanderlei Borba [FURNAS, Rio de Janeiro, RJ (Brazil); Fetterman, R.J. [Westinghouse Electric Corp., Pittsburgh, PA (United States)

    1995-12-31

    The ALPHA/PHOENIX-P/ANC (APA) code package was used to calculate the pin by pin power distribution and reactivity for Angra 1 Power Plant, Cycle 5. The Angra 1 Cycle 5 core was loaded with several irradiated fuel elements which were stored in the Spent Fuel Pool (SFP) for more than 8 years. Generally, neutronic codes take into account the buildup and depletion of just a few key fission, products such as Sm-149. In this paper it is shown that the buildup effects of other fission products must be considered for fuel which has been out of the core for significant periods of time. Impacts of these other fission products can change core reactivity and power distribution. (author). 3 refs, 4 figs, 4 tabs.

  16. Long term storage effects of irradiated fuel elements on power distribution and reactivity

    Ponzoni Filho, P.; Sato, Sadakatu; Santos, Teresinha Ipojuca Cardoso T.I.C.; Fernandes Vanderlei Borba; Fetterman, R.J.

    1995-01-01

    The ALPHA/PHOENIX-P/ANC (APA) code package was used to calculate the pin by pin power distribution and reactivity for Angra 1 Power Plant, Cycle 5. The Angra 1 Cycle 5 core was loaded with several irradiated fuel elements which were stored in the Spent Fuel Pool (SFP) for more than 8 years. Generally, neutronic codes take into account the buildup and depletion of just a few key fission, products such as Sm-149. In this paper it is shown that the buildup effects of other fission products must be considered for fuel which has been out of the core for significant periods of time. Impacts of these other fission products can change core reactivity and power distribution. (author). 3 refs, 4 figs, 4 tabs

  17. Study of the Reactive-element Effect in Oxidation of Fe-cr Alloys Using Transverse Section Analytical Electron Microscopy

    King, W. E.; Ethridge, E. C.

    1985-01-01

    The role of trace additions of reactive elements like Y, Ce, Th, or Hf to Cr bearing alloys was studied by applying a new developed technique of transverse section analytical electron microscopy. This reactive-element effect improves the high temperature oxidation resistance of alloys by strongly reducing the high temperature oxidation rate and enhancing the adhesion of the oxide scale, however, the mechanisms for this important effect remain largely unknown. It is indicated that the presence of yttrium affects the oxidation of Fe-Cr-Y alloys in at least two ways. The reactive element alters the growth mechanism of the oxide scale as evidenced by the marked influence of the reactive element on the oxide scale microstructure. The present results also suggest that reactive-element intermetallic compounds, which internally oxidize in the metal during oxidation, act as sinks for excess vacancies thus inhibiting vacancy condensation at the scale-metal interface and possibly enhancing scale adhesion.

  18. EFFECT OF UV IRRADIATION ON THE DYEING OF COTTON FABRIC WITH REACTIVE BLUE 204

    ROŞU Liliana

    2017-05-01

    Full Text Available Reactive dyes are synthetic organic compounds used on a wide scale in textile industry, for painting materials of different types and compositions (e.g. 100% cotton, wool, natural satin, viscose, synthetic fibres. Reactive dyes are solid compounds (powders completely water soluble at normal temperature and pressure conditions. Their structures contain chromophore groups, which generate colour, and auxochrome groups, which determine the compounds water solubility and the capacity to fix to the textile fiber. Such organic compounds absorb UV-Vis radiations at specific wavelengths, corresponding to maximum absorbtion peaks, in both solution and dyed fiber. The human organism, through the dyed clothing, comes in direct contact with those dyes which can undergo modifications once exposed to UV radiations, having the posibility to reach the organism via cutanated transport. As it is known, the provoked negative effects are stronger during summer when UV radiations are more intense and in order to reduce their intensity dark coloured clothing is avoided. Dyes can be transformed in compounds which are easily absorbed into the skin. Some of these metabolites can be less toxic than the original corresponding dye, whilst others, such as free radicals, are potentially cancerous. Knowledge of the biological effects of the organic dyes, reactive dyes in particular, correlated with their structural and physical characteristics, permanently consists an issue of high scientific and practical interest and its solution may contribute in the diminishing of risk factors and improving of population health. UV radiation influence on the structural and colour modifications of textile materials were studied. Colour modifications are due to structural changes in aromatic and carbonil groups. In most cases photo-oxidative processes were identified in the dye structure. Dyeing was performed using non-irradiated and irradiated cotton painted with reactive blue dye 204.

  19. Effectiveness of reactive case detection for malaria elimination in three archetypical transmission settings: a modelling study.

    Gerardin, Jaline; Bever, Caitlin A; Bridenbecker, Daniel; Hamainza, Busiku; Silumbe, Kafula; Miller, John M; Eisele, Thomas P; Eckhoff, Philip A; Wenger, Edward A

    2017-06-12

    reactive case detection or mass drug campaigns. Reactive case detection is recommended only for settings where transmission has recently been reduced rather than all low-transmission settings. This is demonstrated in a modelling framework with strong out-of-sample accuracy across a range of transmission settings while including methodologies for understanding the most resource-effective allocations of health workers. This approach generalizes to providing a platform for planning rational scale-up of health systems based on locally-optimized impact according to simplified stratification.

  20. Proactive and reactive effects of vigorous exercise on learning and vocabulary comprehension.

    Salis, Andrea S

    2013-06-01

    College students (N = 90) were randomly assigned to participate in vigorous, moderate or no physical exercise and vocabulary recall and comprehension learning activities under varying conditions to assess whether or not increased intensities of exercise, performed either before a vocabulary recall and comprehension learning activity (i.e., proactive effect) or after a vocabulary recall and comprehension learning activity (i.e., reactive effect), would improve vocabulary recall and comprehension. The results demonstrated that performing exercise at a vigorous intensity before or after rehearsing for a vocabulary comprehension test improved test results.

  1. Effects of interpretation training on hostile attribution bias and reactivity to interpersonal insult.

    Hawkins, Kirsten A; Cougle, Jesse R

    2013-09-01

    Research suggests that individuals high in anger have a bias for attributing hostile intentions to ambiguous situations. The current study tested whether this interpretation bias can be altered to influence anger reactivity to an interpersonal insult using a single-session cognitive bias modification program. One hundred thirty-five undergraduate students were randomized to receive positive training, negative training, or a control condition. Anger reactivity to insult was then assessed. Positive training led to significantly greater increases in positive interpretation bias relative to the negative group, though these increases were only marginally greater than the control group. Negative training led to increased negative interpretation bias relative to other groups. During the insult, participants in the positive condition reported less anger than those in the control condition. Observers rated participants in the positive condition as less irritated than those in the negative condition and more amused than the other two conditions. Though mediation of effects via bias modification was not demonstrated, among the positive condition posttraining interpretation bias was correlated with self-reported anger, suggesting that positive training reduced anger reactivity by influencing interpretation biases. Findings suggest that positive interpretation training may be a promising treatment for reducing anger. However, the current study was conducted with a non-treatment-seeking student sample; further research with a treatment-seeking sample with problematic anger is necessary. Copyright © 2013. Published by Elsevier Ltd.

  2. Effective Proactive and Reactive Defense Strategies against Malicious Attacks in a Virtualized Honeynet

    Frank Yeong-Sung Lin

    2013-01-01

    Full Text Available Virtualization plays an important role in the recent trend of cloud computing. It allows the administrator to manage and allocate hardware resources flexibly. However, it also causes some security issues. This is a critical problem for service providers, who simultaneously strive to defend against malicious attackers while providing legitimate users with high quality service. In this paper, the attack-defense scenario is formulated as a mathematical model where the defender applies both proactive and reactive defense mechanisms against attackers with different attack strategies. In order to simulate real-world conditions, the attackers are assumed to have incomplete information and imperfect knowledge of the target network. This raises the difficulty of solving the model greatly, by turning the problem nondeterministic. After examining the experiment results, effective proactive and reactive defense strategies are proposed. This paper finds that a proactive defense strategy is suitable for dealing with aggressive attackers under “winner takes all” circumstances, while a reactive defense strategy works better in defending against less aggressive attackers under “fight to win or die” circumstances.

  3. Cortisol response mediates the effect of post-reactivation stress exposure on contextualization of emotional memories.

    Bos, Marieke G N; Jacobs van Goethem, Tessa H; Beckers, Tom; Kindt, Merel

    2014-12-01

    Retrieval of traumatic experiences is often accompanied by strong feelings of distress. Here, we examined in healthy participants whether post-reactivation stress experience affects the context-dependency of emotional memory. First, participants studied words from two distinctive emotional categories (i.e., war and disease) presented against a category-related background picture. One day later, participants returned to the lab and received a reminder of the words of one emotional category followed by exposure to a stress task (Stress group, n=22) or a control task (Control group, n=24). Six days later, memory contextualization was tested using a word stem completion task. Half of the word stems were presented against the encoding context (i.e., congruent context) and the other half of the word stems were presented against the other context (i.e., incongruent context). The results showed that participants recalled more words in the congruent context than in the incongruent context. Interestingly, cortisol mediated the effect of stress exposure on memory contextualization. The stronger the post-reactivation cortisol response, the more memory performance relied on the contextual embedding of the words. Taken together, the current findings suggest that a moderate cortisol response after memory reactivation might serve an adaptive function in preventing generalization of emotional memories over contexts. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. [Effects of allelochemical dibutyl phthalate on Gymnodinium breve reactive oxygen species].

    Bie, Cong-Cong; Li, Feng-Min; Li, Yuan-Yuan; Wang, Zhen-Yu

    2012-02-01

    The purpose of this study was to investigate the mechanism of inhibitory action of dibutyl phthalate (DBP) on red tide algae Gymnodinium breve. Reactive oxygen species (ROS) level, contents of *OH and H2O2, and O2*(-) production rate were investigated, and also for the effects of electron transfer inhibitors on the ROS induction of DBP. The results showed that DBP triggered the synthesis of reactive oxygen species ROS, and with the increase of concentration of DBP, *OH and H2O2 contents in cells accumulated, as for the 3 mg x L(-1) DBP treated algae cultures, OH showed a peak of 33 U x mL(-1) at 48 h, which was about 2. 4 times higher than that in the controlled, and H2O2 contents was about 250 nmol x (10(7) cells)(-1) at 72 h, which was about 5 times higher and also was the highest during the whole culture. Rotenone (an inhibitor of complex I in the mitochondria electron transport chain) decreased the DBP induced ROS production, and dicumarol (an inhibitor of the redox enzyme system in the plasma membrane) stimulated the DBP induced ROS production. Taken all together, the results demonstrated DBP induced over production of reactive oxygen species in G. breve, which is the main inhibitory mechanism, and mitochondria and plasma membrane seem to be the main target site of DBP. These conclusions were of scientific meaning on uncovering the inhibitory mechanism of allelochemical on algae.

  5. Reduced enrichment fuel and its reactivity effects in the University Training Reactor Moata

    Wilson, D.J.

    1983-08-01

    Concern for nuclear proliferation is likely to preclude future supply of highly enriched uranium fuel for research reactors such as the University Training Reactor Moata. This study calculates the fuel densities necessary to maintain the reactivity per plate of the present high enrichment (90 per cent 235 U) fuel for a range of lower enrichments assuming that no geometry changes are allowed. The maximum uranium density for commercially available aluminium-type research reactor fuels is generally considered to be about 1.7 g cm -3 . With this density limitation, the minimum enrichment to maintain present reactivity per plate is about 35 per cent 235 U. For low enrichment (max. 20 per cent 235 U) fuel, the required U density is about 2.9 g cm -3 , which is beyond the expected range for UAl/sub x/-Al but within that projected for the longer term development and full qualification for U 3 O 8 -Al. Medium enrichment (nominally 45 per cent 235 U) Al/sub x/-Al would be entirely satisfactory as an immediate replacement fuel, requiring no modifications to the reactor and operating procedures, and minimal reappraisal of safety issues. Included in this study are calculations of the fuel coefficients at various enrichments, the effect of replacing standard fuel plates or complete elements with 45 per cent enriched fuel, and the reactivity to be gained by replacing 12-plate with 13-plate elements

  6. Studies of the reactivity effects of hydrogenous material in a sodium cooled fast reactor

    Ingram, D.; Sweet, D.W.

    1979-01-01

    The reactivity effects of hydrogenous substances, such as the oil used in the primary coolant pumps, which could enter the core of a fast reactor in a hypothetical accident, have been studied in a series of experiments and calculations. Measurements to study the influence of the density of the hydrogen and its location on reactivity were made in two assemblies in the zero power reactor ZEBRA. The first of these was similar in size to PFR and the second was the large BZB assembly of the BIZET programme. The results of this work have been compared with calculations using the FGL5 nuclear data library. Calculations for a 1200 MW (e) CFR have been made using three quantities of material (8, 40 and 160 Kg of hydrocarbon, equivalent to 10, 50 and 200 litres of oil). The calculations have used different geometrical models and hydrocarbon distributions and have explored the influence of core temperature, fuel burn-up and the presence of control rods to estimate the maximum reactivity changes that can be obtained. The results have been analysed in terms of components of the change in neutron balance produced by the material and uncertainties in these have been derived from the ZEBRA work. (author)

  7. Reactive species in non-equilibrium atmospheric-pressure plasmas: Generation, transport, and biological effects

    Lu, X., E-mail: luxinpei@hotmail.com [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Naidis, G.V. [Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412 (Russian Federation); Laroussi, M. [Plasma Engineering & Medicine Institute, Old Dominion University, Norfolk, VA 23529 (United States); Reuter, S. [Leibniz Institute for Plasma Science and Technology, Felix-Hausdorff-Strasse 2, 17489 Greifswald (Germany); Graves, D.B. [Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720 (United States); Ostrikov, K. [Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000 (Australia); School of Physics, Chemistry, and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4000 (Australia); Commonwealth Scientific and Industrial Research Organization, P.O.Box 218, Lindfield, NSW 2070 (Australia); School of Physics, The University of Sydney, Sydney, NSW 2006 (Australia)

    2016-05-04

    Non-equilibrium atmospheric-pressure plasmas have recently become a topical area of research owing to their diverse applications in health care and medicine, environmental remediation and pollution control, materials processing, electrochemistry, nanotechnology and other fields. This review focuses on the reactive electrons and ionic, atomic, molecular, and radical species that are produced in these plasmas and then transported from the point of generation to the point of interaction with the material, medium, living cells or tissues being processed. The most important mechanisms of generation and transport of the key species in the plasmas of atmospheric-pressure plasma jets and other non-equilibrium atmospheric-pressure plasmas are introduced and examined from the viewpoint of their applications in plasma hygiene and medicine and other relevant fields. Sophisticated high-precision, time-resolved plasma diagnostics approaches and techniques are presented and their applications to monitor the reactive species and plasma dynamics in the plasma jets and other discharges, both in the gas phase and during the plasma interaction with liquid media, are critically reviewed. The large amount of experimental data is supported by the theoretical models of reactive species generation and transport in the plasmas, surrounding gaseous environments, and plasma interaction with liquid media. These models are presented and their limitations are discussed. Special attention is paid to biological effects of the plasma-generated reactive oxygen and nitrogen (and some other) species in basic biological processes such as cell metabolism, proliferation, survival, etc. as well as plasma applications in bacterial inactivation, wound healing, cancer treatment and some others. Challenges and opportunities for theoretical and experimental research are discussed and the authors’ vision for the emerging convergence trends across several disciplines and application domains is presented to

  8. Effect of ectomycorrhizal colonization and drought on reactive oxygen species metabolism of Nothofagus dombeyi roots.

    Alvarez, Maricel; Huygens, Dries; Fernandez, Carlos; Gacitúa, Yessy; Olivares, Erick; Saavedra, Isabel; Alberdi, Miren; Valenzuela, Eduardo

    2009-08-01

    Infection with ectomycorrhizal fungi can increase the ability of plants to resist drought stress through morphophysiological and biochemical mechanisms. However, the metabolism of antioxidative enzyme activities in the ectomycorrhizal symbiosis remains poorly understood. This study investigated biomass production, reactive oxygen metabolism (hydrogen peroxide and malondialdehyde concentration) and antioxidant enzyme activity (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase) in pure cultures of the ectomycorrhizal fungi Descolea antartica Sing. and Pisolithus tinctorius (Pers.) Coker & Couch, and non-mycorrhizal and mycorrhizal roots of Nothofagus dombeyi (Mirb.) roots under well-watered conditions and drought conditions (DC). The studied ectomycorrhizal fungi regulated their antioxidative enzyme metabolism differentially in response to drought, resulting in cellular damage in D. antartica but not in P. tinctorius. Ectomycorrhizal inoculation and water treatment had a significant effect on all parameters studied, including relative water content of the plant. As such, N. dombeyi plants in symbiosis experienced a lower oxidative stress effect than non-mycorrhizal plants under DC. Additionally, ectomycorrhizal N. dombeyi roots showed a greater antioxidant enzyme activity relative to non-mycorrhizal roots, an effect which was further expressed under DC. The association between the non-specific P. tinctorius and N. dombeyi had a more effective reactive oxygen species (ROS) metabolism than the specific D. antartica-N. dombeyi symbiosis. We conclude that the combination of effective ROS prevention and ROS detoxification by ectomycorrhizal plants resulted in reduced cellular damage and increased plant growth relative to non-mycorrhizal plants under drought.

  9. Effect of packing fraction variations on reactivity in pebble-bed reactor

    Snoj, L.; Ravnik, M.

    2004-01-01

    The pebble-bed reactor (PBR) core consists of large number of randomly packed spherical fuel elements. The effect of fuel element packing density variations on multiplication factor in a typical PBR is studied using WIMS code. It is observed that at normal conditions the k-eff increases with packing fraction. Effects of secondary coolant ingress (water or molten lead) in the core at accidental conditions are studied at various packing densities. The effect of water ingress on reactivity depends strongly on water density and packing fraction and is prevailingly positive, while the lead ingress reduces multiplication factor regardless of lead effective density and packing fraction. Both effects are stronger at lower packing fractions. (author)

  10. Cue reactivity in non-daily smokers: effects on craving and on smoking behavior.

    Shiffman, Saul; Dunbar, Michael S; Kirchner, Thomas R; Li, Xiaoxue; Tindle, Hilary A; Anderson, Stewart J; Scholl, Sarah M; Ferguson, Stuart G

    2013-03-01

    Non-daily, or intermittent smokers (ITS), are increasingly prevalent. Their smoking may be more situational than that of daily smokers (DS), and thus is hypothesized to be more influenced by cues. To assess ITS' response to cues, and compare it to that of DS. Samples of 239 ITS and 207 DS (previously reported in Shiffman et al. 2012a) were studied in 2,586 laboratory cue-reactivity sessions. Craving (Questionnaire of Smoking Urges) and smoking (probability, latency, puff parameters, and carbon monoxide increases) in response to cues was assessed following exposure to neutral cues and cues related to smoking, alcohol, negative affect, positive affect, and smoking prohibitions. Mixed effects models, generalized estimating equations and random-effects survival analyses were used to assess response to cues and differences between DS and ITS. ITS' craving increased following exposure to smoking and alcohol cues and decreased following positive affect cues, but cues had little effect on smoking behaviors. Cue reactivity was similar in ITS and DS. Among ITS, craving intensity predicted smoking probability, latency, and intensity, and the effects on latency were stronger among ITS than DS. Contrary to hypotheses, ITS were not more responsive to laboratory cues than DS. Results show that ITS do experience craving and craving increases that are then associated with smoking.

  11. Reactive Kripke semantics

    Gabbay, Dov M

    2013-01-01

    This text offers an extension to the traditional Kripke semantics for non-classical logics by adding the notion of reactivity. Reactive Kripke models change their accessibility relation as we progress in the evaluation process of formulas in the model. This feature makes the reactive Kripke semantics strictly stronger and more applicable than the traditional one. Here we investigate the properties and axiomatisations of this new and most effective semantics, and we offer a wide landscape of applications of the idea of reactivity. Applied topics include reactive automata, reactive grammars, rea

  12. On the effects of the reactive terms in the Boltzmann equation

    C. J. Zamlutti

    Full Text Available The effects of the production and loss mechanisms that affect the Boltzmann equations are considered by the inclusion of a reactive term. The necessary elements to develop a proper form for this term are revised and the current trends analyzed. Although no accurate theoretical treatment of the problem is possible due to the many body nature of it, important relations can be derived which, besides being representative of the quantitative aspects of the matter, are illustrative of the qualitative features of the phenomenon. The overall procedure is detailed in this revision.

  13. Process effects on radio frequency diode reactively sputtered ZrO2 films

    Yang, M.M.; Reith, T.M.; Lin, C.J.

    1990-01-01

    The ZrO 2 thin film is deposited by means of a reactive radio frequency diode sputtering from an elemental zirconium target in an argon--oxygen mixture gas. The influence of the deposition process parameters on the microinstructure, composition, film stress, and refractive index is investigated. It is noted that the process parameters, in particular substrate bias, have a profound effect on the structure and properties. The possible mechanism, in terms of bombardment of energetic particles and adatom mobility on the film surface, is discussed

  14. Spectroelectrochemical Sensing Based on Multimode Selectivity simultaneously Achievable in a Single Device. 11. Design and Evaluation of a Small Portable Sensor for the Determination of Ferrocyanide in Hanford Waste Samples

    Stegemiller, Michael L.; Heineman, William R.; Seliskar, Carl J.; Ridgway, Thomas H.; Bryan, Samuel A.; Hubler, Timothy L.; Sell, Richard L.

    2003-01-01

    Spectroelectrochemical sensing based on multimode selectivity simultaneously achievable in a single device. 11. Design and evaluation of a small portable sensor for the determination of ferrocyanide in Hanford waste samples

  15. Reducing Schoolchildren With Reactive Aggression Through Child, Parent, and Conjoint Parent-Child Group Interventions: A Longitudinal Outcome Effectiveness Study.

    Fung, Annis Lai Chu

    2017-10-10

    This study was the first to evaluate the effectiveness of three different group interventions to reduce children's reactive aggression based on the social information processing (SIP) model. In the first stage of screening, 3,734 children of Grades 4-6 completed the Reactive-Proactive Aggression Questionnaire (RPQ) to assess their reactive and proactive aggression. Respondents with a total score of z ≥ 1 on the RPQ were shortlisted for the second stage of screening by qualitative interview. Interviews with 475 children were conducted to select those who showed reactive aggression featuring a hostile attributional bias. Finally, 126 children (97 males and 29 females) aged 8 to 14 (M = 9.71, SD = 1.23) were selected and randomly assigned to one of the three groups: a child group, a parent group, and a parent-child group. A significant Time × Intervention effect was found for general and reactive aggression. The parent-child group and child group showed a significant drop in general aggression and reactive aggression from posttest to 6-month follow-up, after controlling for baseline scores, sex, and age. However, the parent group showed no treatment effect: reactive aggression scores were significantly higher than those in the child group at 6-month follow-up. This study has provided strong evidence that children with reactive aggression need direct and specific treatment to reconstruct the steps of the SIP involving the selection and interpretation of cues. The intervention could help to prevent severe violent crimes at the later stage of a reactive aggressor. © 2017 Family Process Institute.

  16. Preliminary investigation of actinide and xenon reactivity effects in accelerator transmutation of waste high-flux systems

    Olson, K.R.; Henderson, D.L.

    1995-01-01

    The possibility of an unstable positive reactivity growth in an accelerator transmutation of waste (ATW)-type high-flux system is investigated. While it has always been clear that xenon is an important actor in the reactivity response of a system to flux changes, it has been suggested that in very high thermal flux transuranic burning systems, a positive, unstable reactivity growth could be caused by the actinides alone. Initial system reactivity response to flux changes caused by the actinides and xenon are investigated separately. The maximum change in reactivity after a flux change caused by the effect of the changing quantities of actinides is generally at least two orders of magnitude smaller than either the positive or negative reactivity effect associated with xenon after a shutdown or startup. In any transient flux event, the reactivity response of the system to xenon will generally occlude the response caused by the actinides. The capabilities and applications of both the current actinide model and the xenon model are discussed. Finally, the need for a complete dynamic model for the high-flux fluid-fueled ATW system is addressed

  17. Effect of heavy metals ondecolorization of reactive brilliant red by newly isolated microorganisms

    Nosheen, S.; Arshad, M.

    2011-01-01

    This study involves aerobic decolorisation of reactive azo dye reactive brilliant red 2KBP by newly isolated microbial strains (two bacterial and one fungal strain) in presence of heavy metals including cobalt chloride, ferric chloride, zinc sulphate, copper sulphate and nickel chloride. Many heavy metals are necessary for microbial growth and are required in very small amounts however at higher levels they become toxic. So was the objective of present work to check the effect of concentration of heavy metals on the potential of microbial strains to decolorize azo dyes. All the heavy metals under consideration were added in range of 0.5 gl-1-2.5gl/sup -1/. All heavy metals showed inhibitory effect on decolorization capacity of bacterial as well as fungal strain .At optimum conditions bacterial strains named as B1 and B2 removed 84% and 78% while fungal strain decolorized 90.4% of dye. Cobalt and nickel showed greater inhibitors on% decolorization of dyes than Zinc and iron. Fungal strain showed greater negative effect. Heavy metals might affect enzyme activities and thus reducing removal of dye. (author)

  18. Effects of Reactive Oxygen Species on Tubular Transport along the Nephron.

    Gonzalez-Vicente, Agustin; Garvin, Jeffrey L

    2017-03-23

    Reactive oxygen species (ROS) are oxygen-containing molecules naturally occurring in both inorganic and biological chemical systems. Due to their high reactivity and potentially damaging effects to biomolecules, cells express a battery of enzymes to rapidly metabolize them to innocuous intermediaries. Initially, ROS were considered by biologists as dangerous byproducts of respiration capable of causing oxidative stress, a condition in which overproduction of ROS leads to a reduction in protective molecules and enzymes and consequent damage to lipids, proteins, and DNA. In fact, ROS are used by immune systems to kill virus and bacteria, causing inflammation and local tissue damage. Today, we know that the functions of ROS are not so limited, and that they also act as signaling molecules mediating processes as diverse as gene expression, mechanosensation, and epithelial transport. In the kidney, ROS such as nitric oxide (NO), superoxide (O₂ - ), and their derivative molecules hydrogen peroxide (H₂O₂) and peroxynitrite (ONO₂ - ) regulate solute and water reabsorption, which is vital to maintain electrolyte homeostasis and extracellular fluid volume. This article reviews the effects of NO, O₂ - , ONO₂ - , and H₂O₂ on water and electrolyte reabsorption in proximal tubules, thick ascending limbs, and collecting ducts, and the effects of NO and O₂ - in the macula densa on tubuloglomerular feedback.

  19. Reactivity effect of non-uniformly distributed fuel in fuel solution systems

    Hirano, Yasushi; Yamane, Yoshihiro; Nishina, Kojiro; Mitsuhashi, Ishi.

    1991-01-01

    A numerical method to determine the optimal fuel distribution for minimum critical mass, or maximum k-effective, is developed using the Maximum Principle in order to evaluate the maximum effect of non-uniformly distributed fuel on reactivity. This algorithm maximizes the Hamiltonian directly by an iterative method under a certain constraint-the maintenance of criticality or total fuel mass. It ultimately reaches the same optimal state of a flattened fuel importance distribution as another algorithm by Dam based on perturbation theory. This method was applied to two kinds of spherical cores with water reflector in the simulating reprocessing facility. In the slightly-enriched uranyl nitrate solution core, the minimum critical mass decreased by less than 1% at the optimal moderation state. In the plutonium nitrate solution core, the k-effective increment amounted up to 4.3% Δk within the range of present study. (author)

  20. Effect of Reactive Black 5 azo dye on soil processes related to C and N cycling

    Khadeeja Rehman

    2018-05-01

    Full Text Available Azo dyes are one of the largest classes of synthetic dyes being used in textile industries. It has been reported that 15–50% of these dyes find their way into wastewater that is often used for irrigation purpose in developing countries. The effect of azo dyes contamination on soil nitrogen (N has been studied previously. However, how does the azo dye contamination affect soil carbon (C cycling is unknown. Therefore, we assessed the effect of azo dye contamination (Reactive Black 5, 30 mg kg−1 dry soil, bacteria that decolorize this dye and dye + bacteria in the presence or absence of maize leaf litter on soil respiration, soil inorganic N and microbial biomass. We found that dye contamination did not induce any change in soil respiration, soil microbial biomass or soil inorganic N availability (P > 0.05. Litter evidently increased soil respiration. Our study concludes that the Reactive Black 5 azo dye (applied in low amount, i.e., 30 mg kg−1 dry soil contamination did not modify organic matter decomposition, N mineralization and microbial biomass in a silty loam soil.

  1. Substrate temperature effects on reactively sputtered Cr2O3/n-Si heterojunctions

    Ocak, Yusuf Selim; Genisel, Mustafa Fatih; Issa, Ali Ahmed; Tombak, Ahmet; Kilicoglu, Tahsin

    2016-01-01

    To see the effects of substrate temperature on Cr 2 O 3 /n-Si heterojunctions, Cr 2 O 3 thin films were formed on n-Si and glass substrates at 40, 150 and 250 °C by radio frequency (RF) reactive sputtering technique. High purity Cr was used as target and oxygen was used as reactive gas. Optical properties of Cr 2 O 3 /n-Si thin films were analyzed using UV-vis data. The band gaps of the films were compared. The electrical properties of Cr 2 O 3 /n-Si heterojunction were tested by their current voltage ( I-V ) measurements in dark. It was observed that the heterojunction which was fabricated by forming Cr 2 O 3 thin film at 250 °C gave better rectification. The characteristic electrical parameters such as barrier height, ideality factor and series resistance were calculated by using its I-V data. The influence of light intensity on photovoltaic effect behavior of the device was also calculated, finally the barrier height value of the structure obtained from capacitance-voltage ( C-V ) data were compared with the one calculated from I-V measurements. (paper)

  2. Effect of static porosity fluctuations on reactive transport in a porous medium

    L'Heureux, Ivan

    2018-02-01

    Reaction-diffusive transport phenomena in porous media are ubiquitous in engineering applications, biological and geochemical systems. The porosity field is usually random in space, but most models consider the porosity field as a well-defined deterministic function of space and time and ignore the porosity fluctuations. They use a reaction-diffusion equation written in terms of an average porosity and average concentration fields. In this contribution, we treat explicitly the effect of spatial porosity fluctuations on the dynamics of a concentration field for the case of a one-dimensional reaction-transport system with nonlinear kinetics. Three basic assumptions are considered. (i) The porosity fluctuations are assumed to have Gaussian properties and an arbitrary variance; (ii) we assume that the noise correlation length is small compared to the relevant macroscopic length scale; (iii) and we assume that the kinetics of the reactive term in the equations for the fluctuations is a self-consistently determined constant. Elimination of the fluctuating part of the concentration field from the dynamics leads to a renormalized equation involving the average concentration field. It is shown that the noise leads to a renormalized (generally smaller) diffusion coefficient and renormalized kinetics. Within the framework of the approximations used, numerical simulations are in agreement with our theory. We show that the porosity fluctuations may have a significant effect on the transport of a reactive species, even in the case of a homogeneous average porosity.

  3. Effects of periodontal therapy on C-reactive protein and HDL in serum of subjects with periodontitis.

    Leite, Anne Carolina Eleutério; Carneiro, Valéria Martins de Araújo; Guimarães, Maria do Carmo Machado

    2014-01-01

    To investigate the effects of nonsurgical periodontal therapy on levels of high-sensitivity C-reactive protein in the sera and its association with body mass index and high density lipoprotein in subjects with severe periodontitis. Sera from 28 subjects (mean age: 34.36±6.24; 32% men) with severe periodontitis and 27 healthy controls (mean age: 33.18±6.42; 33% men) were collected prior to periodontal therapy. Blood samples were obtained from 23 subjects who completed therapy (9-12 months). Oral and systemic parameters such as the number of blood cells, glucose examination, lipid profile, and high-sensitivity C-reactive protein levels accessed by high-sensitivity immunonephelometry assay, were included. Before therapy, in the periodontitis group, the ratio of subjects with high-sensitivity C-reactive protein C-reactive protein C-reactive protein C-reactive protein >0.3 mg/dL (28.91±6.03) (Pperiodontitis, periodontal therapy was associated with decreased levels of circulating high-sensitivity C-reactive protein and increase of high density lipoprotein in serum. The clinical trial was registered at http://www.clinicaltrials.gov.br/, No. RBR-24T799.

  4. Possibilities of achieving non-positive void reactivity effect in fast sodium-cooled reactors with increased self-protection

    Alekseev, P.N.; Zverkov, Yu.A.; Morozov, A.G.; Orlov, V.V.; Slesarev, I.S.; Subbotin, S.A.

    1989-01-01

    The problems of self-protection inhancement for the liquid-metal cooled fast reactors with intra-assembly heterogeneity of the core are studied. Possible approaches to arrangement of such reactors with various powers characterized by high levels of coolant natural circulation, minimum reactivity changes during fuel burn-up and non-positive void effect of reactivity are found. 10 refs.; 11 figs

  5. Cued Memory Reactivation During SWS Abolishes the Beneficial Effect of Sleep on Abstraction.

    Hennies, Nora; Lambon Ralph, Matthew A; Durrant, Simon J; Cousins, James N; Lewis, Penelope A

    2017-08-01

    Extracting regularities from stimuli in our environment and generalizing these to new situations are fundamental processes in human cognition. Sleep has been shown to enhance these processes, possibly by facilitating reactivation-triggered memory reorganization. Here, we assessed whether cued reactivation during slow wave sleep (SWS) promotes the beneficial effect of sleep on abstraction of statistical regularities. We used an auditory statistical learning task, in which the benefit of sleep has been firmly established. Participants were exposed to a probabilistically determined sequence of tones and subsequently tested for recognition of novel short sequences adhering to this same statistical pattern in both immediate and delayed recall sessions. In different groups, the exposure stream was replayed during SWS in the night between the recall sessions (SWS-replay group), in wake just before sleep (presleep replay group), or not at all (control group). Surprisingly, participants who received replay in sleep performed worse in the delayed recall session than the control and the presleep replay group. They also failed to show the association between SWS and task performance that has been observed in previous studies and was present in the controls. Importantly, sleep structure and sleep quality did not differ between groups, suggesting that replay during SWS did not impair sleep but rather disrupted or interfered with sleep-dependent mechanisms that underlie the extraction of the statistical pattern. These findings raise important questions about the scope of cued memory reactivation and the mechanisms that underlie sleep-related generalization. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

  6. Effects of different frequencies of transcutaneous electrical nerve stimulation on venous vascular reactivity

    Franco, O.S.; Paulitsch, F.S.; Pereira, A.P.C.; Teixeira, A.O.; Martins, C.N.; Silva, A.M.V.; Plentz, R.D.M.; Irigoyen, M.C.; Signori, L.U.

    2014-01-01

    Transcutaneous electrical nerve stimulation (TENS) is a type of therapy used primarily for analgesia, but also presents changes in the cardiovascular system responses; its effects are dependent upon application parameters. Alterations to the cardiovascular system suggest that TENS may modify venous vascular response. The objective of this study was to evaluate the effects of TENS at different frequencies (10 and 100 Hz) on venous vascular reactivity in healthy subjects. Twenty-nine healthy male volunteers were randomized into three groups: placebo (n=10), low-frequency TENS (10 Hz, n=9) and high-frequency TENS (100 Hz, n=10). TENS was applied for 30 min in the nervous plexus trajectory from the superior member (from cervical to dorsal region of the fist) at low (10 Hz/200 μs) and high frequency (100 Hz/200 μs) with its intensity adjusted below the motor threshold and intensified every 5 min, intending to avoid accommodation. Venous vascular reactivity in response to phenylephrine, acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was assessed by the dorsal hand vein technique. The phenylephrine effective dose to achieve 70% vasoconstriction was reduced 53% (P<0.01) using low-frequency TENS (10 Hz), while in high-frequency stimulation (100 Hz), a 47% increased dose was needed (P<0.01). The endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) responses were not modified by TENS, which modifies venous responsiveness, and increases the low-frequency sensitivity of α1-adrenergic receptors and shows high-frequency opposite effects. These changes represent an important vascular effect caused by TENS with implications for hemodynamics, inflammation and analgesia

  7. Effects of different frequencies of transcutaneous electrical nerve stimulation on venous vascular reactivity

    Franco, O.S.; Paulitsch, F.S.; Pereira, A.P.C.; Teixeira, A.O. [Universidade Federal do Rio Grande, Faculdade de Medicina, Programa de Pós-Graduação em Ciências da Saúde, Rio Grande, RS, Brasil, Programa de Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal do Rio Grande, Rio Grande, RS (Brazil); Martins, C.N. [Universidade Federal do Rio Grande, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Fisiologia Animal Comparada, Rio Grande, RS, Brasil, Programa de Pós-Graduação em Fisiologia Animal Comparada, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Rio Grande, RS (Brazil); Silva, A.M.V. [Universidade Federal de Santa Maria, Departamento de Fisioterapia e Reabilitação, Santa Maria, RS, Brasil, Departamento de Fisioterapia e Reabilitação, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Plentz, R.D.M. [Universidade Federal de Ciências da Saúde de Porto Alegre, Programa de Pós-Graduação em Ciências da Reabilitação, Programa de Pós-Graduação em Ciências da Saúde, Porto Alegre, RS, Brasil, Programa de Pós-Graduação em Ciências da Saúde, Programa de Pós-Graduação em Ciências da Reabilitação, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS (Brazil); Irigoyen, M.C. [Faculdade de Medicina, Universidade de São Paulo, Instituto do Coração, Unidade de Hipertensão, São Paulo, SP, Brasil, Unidade de Hipertensão, Instituto do Coração, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Signori, L.U. [Universidade Federal do Rio Grande, Faculdade de Medicina, Programa de Pós-Graduação em Ciências da Saúde, Rio Grande, RS, Brasil, Programa de Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal do Rio Grande, Rio Grande, RS (Brazil); Universidade Federal do Rio Grande, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Fisiologia Animal Comparada, Rio Grande, RS, Brasil, Programa de Pós-Graduação em Fisiologia Animal Comparada, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Rio Grande, RS (Brazil); Universidade Federal de Santa Maria, Departamento de Fisioterapia e Reabilitação, Santa Maria, RS, Brasil, Departamento de Fisioterapia e Reabilitação, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil)

    2014-04-04

    Transcutaneous electrical nerve stimulation (TENS) is a type of therapy used primarily for analgesia, but also presents changes in the cardiovascular system responses; its effects are dependent upon application parameters. Alterations to the cardiovascular system suggest that TENS may modify venous vascular response. The objective of this study was to evaluate the effects of TENS at different frequencies (10 and 100 Hz) on venous vascular reactivity in healthy subjects. Twenty-nine healthy male volunteers were randomized into three groups: placebo (n=10), low-frequency TENS (10 Hz, n=9) and high-frequency TENS (100 Hz, n=10). TENS was applied for 30 min in the nervous plexus trajectory from the superior member (from cervical to dorsal region of the fist) at low (10 Hz/200 μs) and high frequency (100 Hz/200 μs) with its intensity adjusted below the motor threshold and intensified every 5 min, intending to avoid accommodation. Venous vascular reactivity in response to phenylephrine, acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was assessed by the dorsal hand vein technique. The phenylephrine effective dose to achieve 70% vasoconstriction was reduced 53% (P<0.01) using low-frequency TENS (10 Hz), while in high-frequency stimulation (100 Hz), a 47% increased dose was needed (P<0.01). The endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) responses were not modified by TENS, which modifies venous responsiveness, and increases the low-frequency sensitivity of α1-adrenergic receptors and shows high-frequency opposite effects. These changes represent an important vascular effect caused by TENS with implications for hemodynamics, inflammation and analgesia.

  8. Effect of Acute Hypoxia on Post-Exercise Parasympathetic Reactivation in Healthy Men

    Al Haddad, Hani; Mendez-Villanueva, Alberto; Bourdon, Pitre C.; Buchheit, Martin

    2012-01-01

    In this study we assessed the effect of acute hypoxia on post-exercise parasympathetic reactivation inferred from heart rate (HR) recovery (HRR) and HR variability (HRV) indices. Ten healthy males participated in this study. Following 10 min of seated rest, participants performed 5 min of submaximal running at the speed associated with the first ventilatory threshold (Sub) followed by a 20-s all-out supramaximal sprint (Supra). Both Sub and Supra runs were immediately followed by 15 min of seated passive recovery. The resting and exercise sequence were performed in both normoxia (N) and normobaric hypoxia (H; FiO2 = 15.4%). HRR indices (e.g., heart beats recovered in the first minute after exercise cessation, HRR60s) and vagal-related HRV indices [i.e., natural logarithm of the square root of the mean of the sum of the squared differences between adjacent normal R–R intervals (Ln rMSSD)] were calculated for both conditions. Difference in the changes between N and H for all HR-derived indices were also calculated for both Sub and Supra. HRR60s was greater in N compared with H following Sub only (60 ± 14 vs. 52 ± 19 beats min−1, P = 0.016). Ln rMSSD was greater in N compared with H (post Sub: 3.60 ± 0.45 vs. 3.28 ± 0.44 ms in N and H, respectively, and post Supra: 2.66 ± 0.54 vs. 2.65 ± 0.63 ms, main condition effect P = 0.02). When comparing the difference in the changes, hypoxia decreased HRR60s (−14.3% ± 17.2 vs. 5.2% ± 19.3; following Sub and Supra, respectively; P = 0.03) and Ln rMSSD (−8.6% ± 7.0 vs. 2.0% ± 13.3, following Sub and Supra, respectively; P = 0.08, Cohen’s effect size = 0.62) more following Sub than Supra. While hypoxia may delay parasympathetic reactivation following submaximal exercise, its effect is not apparent following supramaximal exercise. This may suggest that the effect of blood O2 partial pressure on parasympathetic reactivation is limited

  9. Reactive nitrogen in the environment and its effect on climate change

    Erisman, J.W.; Bleeker, A.; Galloway, J.; Seitzinger, S.; Butterbach-Bahl, K.

    2011-01-01

    Humans have doubled levels of reactive nitrogen in circulation, largely as a result of fertilizer application and fossil fuel burning. This massive alteration of the nitrogen cycle affects climate, food security, energy security, human health and ecosystem services. Our estimates show that nitrogen currently leads to a net-cooling effect on climate with very high uncertainty. The many complex warming and cooling interactions between nitrogen and climate need to be better assessed, taking also into account the other effects of nitrogen on human health, environment and ecosystem services. Through improved nitrogen management substantial reductions in atmospheric greenhouse gas concentrations could be generated, also allowing for other co-benefits, including improving human health and improved provision of ecosystem services, for example clean air and water, and biodiversity.

  10. Scaling of Anomalous Hall Effects in Facing-Target Reactively Sputtered Fe4N Films

    Zhang, Yan

    2015-05-13

    Anomalous Hall effect (AHE) in the reactively sputtered epitaxial and polycrystalline γ′-Fe4N films is investigated systematically. The Hall resistivity is positive in the entire temperature range. The magnetization, carrier density and grain boundaries scattering have a major impact on the AHE scaling law. The scaling exponent γ in the conventional scaling of is larger than 2 in both the epitaxial and polycrystalline γ′-Fe4N films. Although γ>2 has been found in heterogeneous systems due to the effects of the surface and interface scattering on AHE, γ>2 is not expected in homogenous epitaxial systems. We demonstrated that γ>2 results from residual resistivity (ρxx0) in γ′-Fe4N films. Furthermore, the side-jump and intrinsic mechanisms are dominant in both epitaxial and polycrystalline samples according to the proper scaling relation.

  11. Pavlovian conditioning of shock-induced suppression of lymphocyte reactivity: acquisition, extinction, and preexposure effects.

    Lysle, D T; Cunnick, J E; Fowler, H; Rabin, B S

    1988-01-01

    Recent research has indicated that physical stressors, such as electric shock, can suppress immune function in rats. The present study investigated whether a nonaversive stimulus that had been associated with electric shock would also impair immune function. Presentation of that conditioned stimulus (CS) by itself produced a pronounced suppression of lymphocyte proliferation in response to the nonspecific mitogens, Concanavalin-A (ConA) and Phytohemagglutinin (PHA). In further evidence of a conditioning effect, the suppression was attenuated by extinction and preexposure manipulations that degraded the associative value of the CS. These results indicate that a psychological or learned stressor can suppress immune reactivity independently of the direct effect of physically aversive stimulation or of ancillary changes in dietary and health-related habits.

  12. Long-Term Effectiveness of Stress Management at Work: Effects of the Changes in Perceived Stress Reactivity on Mental Health and Sleep Problems Seven Years Later.

    Herr, Raphael M; Barrech, Amira; Riedel, Natalie; Gündel, Harald; Angerer, Peter; Li, Jian

    2018-02-03

    The reduction of stress reactivity resulting from stress management interventions prevents disorders and improves mental health, however, its long-term sustainability has been little examined. The objective of this study was, therefore, to determine the effectiveness of a stress management intervention, designed to improve stress reactivity, for mental health and sleep problems seven years later, using longitudinal data from 101 male industrial workers. Linear regressions estimated the adjusted effects of the changes in stress reactivity in general as well as in its six subdimensions (work overload, social conflict, social stress, failure at work, and anticipatory and prolonged reactivity) on depression, anxiety, and sleep problems seven years later. The improvement of the prolonged reactivity had positive effects on depression, anxiety, and sleep problems (unstandardized regression coefficients [ Bs ] ≥ 0.35, all p -values ≤ 0.01). Depression and sleep problems were further improved by a reduction of the reactivity to social conflicts ( Bs ≥ 0.29, p -values stress reactivity resulting from a work stress intervention was effective and generally long-lasting in preventing mental health and sleep problems. The reduction of the prolonged reactivity seems of particular importance and efficient in inhibiting negative stress manifestations.

  13. Effects of Social Exclusion on Cardiovascular and Affective Reactivity to a Socially Evaluative Stressor.

    Williamson, Timothy J; Thomas, KaMala S; Eisenberger, Naomi I; Stanton, Annette L

    2018-04-03

    Socially disconnected individuals have worse health than those who feel socially connected. The mechanisms through which social disconnection influences physiological and psychological outcomes warrant study. The current study tested whether experimental manipulations of social exclusion, relative to inclusion, influenced subsequent cardiovascular (CV) and affective reactivity to socially evaluative stress. Young adults (N = 81) were assigned through block randomization to experience either social exclusion or inclusion, using a standardized computer-based task (Cyberball). Immediately after exposure to Cyberball, participants either underwent a socially evaluative stressor or an active control task, based on block randomization. Physiological activity (systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR)) and state anxiety were assessed throughout the experiment. Excluded participants evidenced a significant increase in cardiovascular and affective responses to a socially evaluative stressor. Included participants who underwent the stressor evidenced similar increases in anxiety, but systolic blood pressure, diastolic blood pressure, and heart rate did not change significantly in response to the stressor. Results contribute to the understanding of physiological consequences of social exclusion. Further investigation is needed to test whether social inclusion can buffer CV stress reactivity, which would carry implications for how positive social factors may protect against the harmful effects of stress.

  14. VOC reactivity and its effect on ozone production during the HaChi summer campaign

    L. Ran

    2011-05-01

    Full Text Available Measurements of ozone and its precursors conducted within the HaChi (Haze in China project in summer 2009 were analyzed to characterize volatile organic compounds (VOCs and their effects on ozone photochemical production at a suburban site in the North China Plain (NCP. Ozone episodes, during which running 8-h average ozone concentrations exceeding 80 ppbv lasted for more than 4 h, occurred on about two thirds of the observational days during the 5-week field campaign. This suggests continuous ozone exposure risks in this region in the summer. Average concentrations of nitrogen oxides (NOx and VOCs are about 20 ppbv and 650 ppbC, respectively. On average, total VOC reactivity is dominated by anthropogenic VOCs. The contribution of biogenic VOCs to total ozone-forming potential, however, is also considerable in the daytime. Key species associated with ozone photochemical production are 2-butenes (18 %, isoprene (15 %, trimethylbenzenes (11 %, xylenes (8.5 %, 3-methylhexane (6 %, n-hexane (5 % and toluene (4.5 %. Formation of ozone is found to be NOx-limited as indicated by measured VOCs/NOx ratios and further confirmed by a sensitivity study using a photochemical box model NCAR_MM. The Model simulation suggests that ozone production is also sensitive to changes in VOC reactivity under the NOx-limited regime, although this sensitivity depends strongly on how much NOx is present.

  15. Reactive Molecular Dynamics Simulations to Understand Mechanical Response of Thaumasite under Temperature and Strain Rate Effects.

    Hajilar, Shahin; Shafei, Behrouz; Cheng, Tao; Jaramillo-Botero, Andres

    2017-06-22

    Understanding the structural, thermal, and mechanical properties of thaumasite is of great interest to the cement industry, mainly because it is the phase responsible for the aging and deterioration of civil infrastructures made of cementitious materials attacked by external sources of sulfate. Despite the importance, effects of temperature and strain rate on the mechanical response of thaumasite had remained unexplored prior to the current study, in which the mechanical properties of thaumasite are fully characterized using the reactive molecular dynamics (RMD) method. With employing a first-principles based reactive force field, the RMD simulations enable the description of bond dissociation and formation under realistic conditions. From the stress-strain curves of thaumasite generated in the x, y, and z directions, the tensile strength, Young's modulus, and fracture strain are determined for the three orthogonal directions. During the course of each simulation, the chemical bonds undergoing tensile deformations are monitored to reveal the bonds responsible for the mechanical strength of thaumasite. The temperature increase is found to accelerate the bond breaking rate and consequently the degradation of mechanical properties of thaumasite, while the strain rate only leads to a slight enhancement of them for the ranges considered in this study.

  16. Investigation of Reactive Power Control Effects on Flicker and Harmonics Emission of a DFIG Wind Turbine

    Amir Nagizadeh Ghoogdareh

    2013-01-01

    Full Text Available One of the most important power quality aspects in wind farms is voltage fluctuation or flicker which should be investigated due to the nature of wind speed variations. These variations result in power and voltage fluctuations at the load bus. Moreover, the wind generation systems may be assumed as a harmonics source because of their power electronic converters. There are numerous factors that affect flicker and harmonic emission of grid-connected wind turbines during continuous operation, such as wind characteristics (e.g. mean wind speed, turbulence intensity, type of generator and grid conditions (e.g. short circuit capacity, grid impedance angle. In this paper, an IEC based flickermeter is first modeled and then a variable speed wind turbine has been simulated by Matlab/Simulink software. The flicker and harmonics emissions of wind turbines equipped with DFIG during continuous operation and using output reactive control are investigated. The simulation results show that control of wind turbine output reactive power is an effective means for flicker mitigation during continuous operation. However, there should be a compromise between flicker reduction and harmonics level increase to enhance the whole power quality of wind turbine.

  17. Effect of pyrolysis pressure and heating rate on radiata pine char structure and apparent gasification reactivity

    E. Cetin; R. Gupta; B. Moghtaderi [University of Newcastle, Callaghan, NSW (Australia). Discipline of Chemical Engineering, Faculty of Engineering and Built Environment, School of Engineering

    2005-07-01

    The knowledge of biomass char gasification kinetics has considerable importance in the design of advanced biomass gasifiers, some of which operate at high pressure. The char gasification kinetics themselves are influenced by char structure. In this study, the effects of pyrolysis pressure and heating rate on the char structure were investigated using scanning electron microscopy (SEM) analysis, digital cinematography, and surface area analysis. Char samples were prepared at pressures between 1 and 20 bar, temperatures ranging from 800 to 1000{degree}C, and heating rates between 20 and 500{degree}C/s. Our results indicate that pyrolysis conditions have a notable impact on the biomass char morphology. Pyrolysis pressure, in particular, was found to influence the size and the shape of char particles while high heating rates led to plastic deformation of particles (i.e. melting) resulting in smooth surfaces and large cavities. The global gasification reactivities of char samples were also determined using thermogravimetric analysis (TGA) technique. Char reactivities were found to increase with increasing pyrolysis heating rates and decreasing pyrolysis pressure. 22 refs., 8 figs., 2 tabs.

  18. The Interactive Effects of Stressful Family Life Events and Cortisol Reactivity on Adolescent Externalizing and Internalizing Behaviors

    Steeger, Christine M.; Cook, Emily C.; Connell, Christian M.

    2016-01-01

    This study investigated the associations between stressful family life events and adolescent externalizing and internalizing behaviors, and the interactive effects of family life events and cortisol reactivity on problem behaviors. In a sample of 100 mothers and their adolescents (M age = 15.09; SD age = 0.98; 68% girls), adolescent cortisol reactivity was measured in response to a mother-adolescent conflict interaction task designed to elicit a stress response. Mothers reported on measures of family life events and adolescent problem behaviors. Results indicated that a heightened adolescent cortisol response moderated the relations between stressful family life events and both externalizing and internalizing behaviors. Results support context-dependent theoretical models, suggesting that for adolescents with higher cortisol reactivity (compared to those with lower cortisol reactivity), higher levels of stressful family life events were associated with greater problem behaviors, whereas lower levels of stressful family life events were related to fewer problem behaviors. PMID:26961703

  19. The influence of spatial effects on the measurement results of reactivity in 'fast disturbances' of core parameters

    Tsyganov, S.V.; Shishkov, L.K.

    2001-01-01

    The analysis of methods for the determination of reactivity revealed an essential influence of spatial effect on the measurement precision. Using of reverse point kinetic equation for reactivity meter is assumed that the average neutron flux weigh with the importance function is known at every moment of the transient. In fact, reactivity meter represent behaviour of the neutron flux only of the part of the core, so measured value of reactivity can differ from really reactivity. Three-dimensional dynamic model of the core allow to evaluate such difference. It is supposed to evaluate correction factor for the neutron flux measured at the place where ion chamber situated with the three-dimensional model NOSTRA of the WWER core. On the basis of such algorithm we propose to build module allowing the influence of spatial effects on the results of the reactivity meter to be eliminated at real time regime. This code will be incorporated into the core monitoring system 'BLOK' (SCORPIO type) which is being developed for the Kola and Rostov NPP. The report illustrates utilization of such algorithm (Authors)

  20. pH effect on decolorization of raw textile wastewater polluted with reactive dyes by advanced oxidation with uv/h2o2

    Racyte, J.; Rimeika, M.; Bruning, H.

    2009-01-01

    The effectiveness of the advanced oxidation process (UV/H2O2) in decolorizing real textile wastewater polluted with commercial reactive dyes - Reactive Yellow 84 and Reactive Red 141 was investigated. All the experiments were performed in a lab-scale reactor with the original high pH of the

  1. Exploring electronic and steric effects on the insertion and polymerization reactivity of phosphinesulfonato pdii catalysts

    Neuwald, Boris

    2013-11-21

    Thirteen different symmetric and asymmetric phosphinesulfonato palladium complexes ([{(X1-Cl)-μ-M}n], M=Na, Li, 1= X(P^O)PdMe) were prepared (see Figure 1). The solid-state structures of the corresponding pyridine or lutidine complexes were determined for (MeO)21-py, (iPrO)21-lut, (MeO,Me2)1-lut, (MeO)31-lut, CF31-lut, and Ph1-lut. The reactivities of the catalysts X1, obtained after chloride abstraction with AgBF4, toward methyl acrylate (MA) were quantified through determination of the rate constants for the first and the consecutive MA insertion and the analysis of β-H and other decomposition products through NMR spectroscopy. Differences in the homo- and copolymerization of ethylene and MA regarding catalyst activity and stability over time, polymer molecular weight, and polar co-monomer incorporation were investigated. DFT calculations were performed on the main insertion steps for both monomers to rationalize the effect of the ligand substitution patterns on the polymerization behaviors of the complexes. Full analysis of the data revealed that: 1) electron-deficient catalysts polymerize with higher activity, but fast deactivation is also observed; 2) the double ortho-substituted catalysts (MeO)21 and (MeO)31 allow very high degrees of MA incorporation at low MA concentrations in the copolymerization; and 3) steric shielding leads to a pronounced increase in polymer molecular weight in the copolymerization. The catalyst properties induced by a given P-aryl (alkyl) moiety were combined effectively in catalysts with two different non-chelating aryl moieties, such as cHexO/(MeO)21, which led to copolymers with significantly increased molecular weights compared to the prototypical MeO1. Catalyst control: The influence of steric and electronic effects on the reactivity of phosphinesulfonato PdII catalysts in polymerization and copolymerization is explored through experimental and DFT methods. A comparison of thirteen different X(P O)PdMe catalysts ((P O)= κ2-P

  2. Beyond a good story: from Hawthorne Effect to reactivity in health professions education research.

    Paradis, Elise; Sutkin, Gary

    2017-01-01

    Observational research is increasingly being used in health professions education (HPE) research, yet it is often criticised for being prone to observer effects (also known as the Hawthorne Effect), defined as a research participant's altered behaviour in response to being observed. This article explores this concern. First, this article briefly reviews the initial Hawthorne studies and the original formulation of the Hawthorne Effect, before turning to contemporary studies of the Hawthorne Effect in HPE and beyond. Second, using data from two observational studies (in the operating theatre and in the intensive care unit), this article investigates the Hawthorne Effect in HPE. Evidence of a Hawthorne Effect is scant, and amounts to little more than a good story. This is surprising given the foundational nature of the Hawthorne Studies in the social sciences and the prevalence of our concern with observer effects in HPE research. Moreover, the multiple and inconsistent uses of the Hawthorne Effect have left researchers without a coherent and helpful understanding of research participants' responses to observation. The authors' HPE research illustrates the complexity of observer effects in HPE, suggests that significant alteration of behaviour is unlikely in many research contexts, and shows how sustained contact with participants over time improves the quality of data collection. This article thus concludes with three recommendations: that researchers, editors and reviewers in the HPE community use the phrase 'participant reactivity' when considering the participant, observer and research question triad; that researchers invest in interpersonal relationships at their study site to mitigate the effects of altered behaviour; and that researchers use theory to make sense of participants' altered behaviour and use it as a window into the social world. The term 'participant reactivity' better reflects current scientific understandings of the research process and

  3. Protective effects of myricitrin against osteoporosis via reducing reactive oxygen species and bone-resorbing cytokines

    Huang, Qiang; Gao, Bo; Wang, Long; Hu, Ya-Qian; Lu, Wei-Guang; Yang, Liu; Luo, Zhuo-Jing; Liu, Jian, E-mail: liujianhq@sina.com

    2014-11-01

    Oxidative stress is a crucial pathogenic factor in the development of osteoporosis. Myricitrin, isolated from Myrica cerifera, is a potent antioxidant. We hypothesized that myricitrin possessed protective effects against osteoporosis by partially reducing reactive oxygen species (ROS) and bone-resorbing cytokines in osteoblastic MC3T3-E1 cells and human bone marrow stromal cells (hBMSCs). We investigated myricitrin on osteogenic differentiation under oxidative stress. Hydrogen peroxide (H{sub 2}O{sub 2}) was used to establish an oxidative cell injury model. Our results revealed that myricitrin significantly improved some osteogenic markers in these cells. Myricitrin decreased lipid production and reduced peroxisome proliferator-activated receptor gamma-2 (PPARγ2) expression in hBMSCs. Moreover, myricitrin reduced the expression of receptor activator of nuclear factor kappa-B ligand (RANKL) and IL-6 and partially suppressed ROS production. In vivo, we established a murine ovariectomized (OVX) osteoporosis model. Our results demonstrated that myricitrin supplementation reduced serum malondialdehyde (MDA) activity and increased reduced glutathione (GSH) activity. Importantly, it ameliorated the micro-architecture of trabecular bones in the 4th lumbar vertebrae (L4) and distal femur. Taken together, these results indicated that the protective effects of myricitrin against osteoporosis are linked to a reduction in ROS and bone-resorbing cytokines, suggesting that myricitrin may be useful in bone metabolism diseases, particularly osteoporosis. - Highlights: • Myricitrin protects MC3T3-E1 cells and hBMSCs from oxidative stress. • It is accompanied by a decrease in oxidative stress and bone-resorbing cytokines. • Myricitrin decreases serum reactive oxygen species to some degree. • Myricitrin partly reverses ovariectomy effects in vivo. • Myricitrin may represent a beneficial anti-osteoporosis treatment method.

  4. Differential pharmacological effects on brain reactivity and plasticity in Alzheimer’s Disease

    Anna-Katharine eBrem

    2013-10-01

    Full Text Available Acetylcholinesterase inhibitors (AChEI are the most commonly prescribed monotherapeutic medications for Alzheimer’s disease (AD. However, their underlying neurophysiological effects remain largely unknown.We investigated the effects of monotherapy (AChEI and combination therapy (AChEI and memantine on brain reactivity and plasticity. Patients treated with monotherapy (AChEI (N=7 were compared to patients receiving combination therapy (COM (N=9 and a group of age-matched, healthy controls (HC (N=13. Cortical reactivity and plasticity of the motor cortex (MC were examined using transcranial magnetic stimulation (TMS. Cognitive functions were assessed with the cognitive subscale of the Alzheimer Disease Assessment Scale (ADAS-Cog, activities of daily living with the ADCS-ADL. In addition we assessed the degree of brain atrophy by measuring brain-scalp distances in seven different brain areas.Patient groups differed in resting motor threshold and brain atrophy, with COM showing a lower motor threshold but less atrophy than AChEI. COM showed similar plasticity effects as the HC group, while plasticity was reduced in AChEI. Long-interval intracortical inhibition (LICI was impaired in both patient groups when compared to HC. ADAS-Cog scores were positively correlated with LICI measures and with brain atrophy, specifically in the left IPL.AD patients treated with mono- or combination therapy show distinct neurophysiological patterns. Further studies should investigate whether these measures might serve as biomarkers of treatment response and whether they could guide other therapeutic interventions.

  5. The effects of applying silicon carbide coating on core reactivity of pebble-bed HTR in water ingress accident

    Zuhair, S.; Setiadipura, Topan [National Nuclear Energy Agency of Indonesia, Serpong Tagerang Selatan (Indonesia). Center for Nuclear Reactor Technology and Safety; Su' ud, Zaki [Bandung Institute of Technology (Indonesia). Dept. of Physics

    2017-03-15

    Graphite is used as the moderator, fuel barrier material, and core structure in High Temperature Reactors (HTRs). However, despite its good thermal and mechanical properties below the radiation and high temperatures, it cannot avoid corrosion as a consequence of an accident of water/air ingress. Degradation of graphite as a main HTR material and the formation of dangerous CO gas is a serious problem in HTR safety. One of the several steps that can be adopted to avoid or prevent the corrosion of graphite by the water/air ingress is the application of a thin layer of silicon carbide (SiC) on the surface of the fuel element. This study investigates the effect of applying SiC coating on the fuel surfaces of pebble-bed HTR in water ingress accident from the reactivity points of view. A series of reactivity calculations were done with the Monte Carlo transport code MCNPX and continuous energy nuclear data library ENDF/B-VII at temperature of 1200 K. Three options of UO{sub 2}, PuO{sub 2}, and ThO{sub 2}/UO{sub 2} fuel kernel were considered to obtain the inter comparison of the core reactivity of pebble-bed HTR in conditions of water/air ingress accident. The calculation results indicated that the UO{sub 2}-fueled pebble-bed HTR reactivity was slightly reduced and relatively more decreased when the thickness of the SiC coating increased. The reactivity characteristic of ThO{sub 2}/UO{sub 2}-fueled pebble-bed HTR showed a similar trend to that of UO{sub 2}, but did not show reactivity peak caused by water ingress. In contrast with UO{sub 2}- and ThO{sub 2}-fueled pebble-bed HTR, although the reactivity of PuO{sub 2}-fueled pebble-bed HTR was the lowest, its characteristics showed a very high reactivity peak (0.33 Δk/k) and this introduction of positive reactivity is difficult to control. SiC coating on the surface of the plutonium fuel pebble has no significant impact. From the comparison between reactivity characteristics of uranium, thorium and plutonium cores with 0

  6. Effect of Relative Humidity and CO2 Concentration on the Properties of Carbonated Reactive MgO Cement Based Materials

    Bilan, Yaroslav

    Sustainability of modern concrete industry recently has become an important topic of scientific discussion, and consequently there is an effort to study the potential of the emerging new supplementary cementitious materials. This study has a purpose to investigate the effect of reactive magnesia (reactive MgO) as a replacement for general use (GU) Portland Cements and the effect of environmental factors (CO2 concentrations and relative humidity) on accelerated carbonation curing results. The findings of this study revealed that improvement of physical properties is related directly to the increase in CO2 concentrations and inversely to the increase in relative humidity and also depends much on %MgO in the mixture. The conclusions of this study helped to clarify the effect of variable environmental factors and the material replacement range on carbonation of reactive magnesia concrete materials, as well as providing an assessment of the optimal conditions for the effective usage of the material.

  7. One-run Monte Carlo calculation of effective delayed neutron fraction and area-ratio reactivity

    Zhaopeng Zhong; Talamo, Alberto; Gohar, Yousry, E-mail: zzhong@anl.gov, E-mail: alby@anl.gov, E-mail: gohar@anl.gov [Nuclear Engineering Division, Argonne National Laboratory, IL (United States)

    2011-07-01

    The Monte Carlo code MCNPX has been utilized to calculate the effective delayed neutron fraction and reactivity by using the area-ratio method. The effective delayed neutron fraction β{sub eff} has been calculated with the fission probability method proposed by Meulekamp and van der Marck. MCNPX was used to calculate separately the fission probability of the delayed and the prompt neutrons by using the TALLYX user subroutine of MCNPX. In this way, β{sub eff} was obtained from the one criticality (k-code) calculation without performing an adjoint calculation. The traditional k-ratio method requires two criticality calculations to calculate β{sub eff}, while this approach utilizes only one MCNPX criticality calculation. Therefore, the approach described here is referred to as a one-run method. In subcritical systems driven by a pulsed neutron source, the area-ratio method is used to calculate reactivity (in dollar units) as the ratio between the prompt and delayed areas. These areas represent the integral of the reaction rates induced from the prompt and delayed neutrons during the pulse period. Traditionally, application of the area-ratio method requires two separate fixed source MCNPX simulations: one with delayed neutrons and the other without. The number of source particles in these two simulations must be extremely high in order to obtain accurate results with low statistical errors because the values of the total and prompt areas are very close. Consequently, this approach is time consuming and suffers from the statistical errors of the two simulations. The present paper introduces a more efficient method for estimating the reactivity calculated with the area method by taking advantage of the TALLYX user subroutine of MCNPX. This subroutine has been developed for separately scoring the reaction rates caused by the delayed and the prompt neutrons during a single simulation. Therefore the method is referred to as a one run calculation. These methodologies have

  8. One-run Monte Carlo calculation of effective delayed neutron fraction and area-ratio reactivity

    Zhaopeng Zhong; Talamo, Alberto; Gohar, Yousry

    2011-01-01

    The Monte Carlo code MCNPX has been utilized to calculate the effective delayed neutron fraction and reactivity by using the area-ratio method. The effective delayed neutron fraction β_e_f_f has been calculated with the fission probability method proposed by Meulekamp and van der Marck. MCNPX was used to calculate separately the fission probability of the delayed and the prompt neutrons by using the TALLYX user subroutine of MCNPX. In this way, β_e_f_f was obtained from the one criticality (k-code) calculation without performing an adjoint calculation. The traditional k-ratio method requires two criticality calculations to calculate β_e_f_f, while this approach utilizes only one MCNPX criticality calculation. Therefore, the approach described here is referred to as a one-run method. In subcritical systems driven by a pulsed neutron source, the area-ratio method is used to calculate reactivity (in dollar units) as the ratio between the prompt and delayed areas. These areas represent the integral of the reaction rates induced from the prompt and delayed neutrons during the pulse period. Traditionally, application of the area-ratio method requires two separate fixed source MCNPX simulations: one with delayed neutrons and the other without. The number of source particles in these two simulations must be extremely high in order to obtain accurate results with low statistical errors because the values of the total and prompt areas are very close. Consequently, this approach is time consuming and suffers from the statistical errors of the two simulations. The present paper introduces a more efficient method for estimating the reactivity calculated with the area method by taking advantage of the TALLYX user subroutine of MCNPX. This subroutine has been developed for separately scoring the reaction rates caused by the delayed and the prompt neutrons during a single simulation. Therefore the method is referred to as a one run calculation. These methodologies have been

  9. Effect of nonsurgical periodontal treatment on C-reactive protein levels in maintenance hemodialysis patients.

    Yazdi, Farin Kiany; Karimi, Noozhan; Rasouli, Manoochehr; Roozbeh, Jamshid

    2013-01-01

    C-reactive protein (CRP) has been implicated as a possible mediator of the association between periodontitis and several systemic diseases. This study evaluated the impact of nonsurgical periodontal treatment on the serum levels of CRP in chronic kidney disease (CKD) patients on hemodialysis. A total of 77 CKD patients on hemodialysis were included in this study. At baseline, periodontal examination was assessed for all the patients, and chronic periodontitis was defined through clinical attachment level and probing pocket depth, according to the American Association of Periodontology. Nonsurgical periodontal treatment was performed and serum levels of CRP were evaluated at baseline and 8 weeks after periodontal treatment. Periodontal treatment resulted in significant reductions in CRP levels (p periodontitis. Periodontitis is an important source of systemic inflammation in CKD patients. Nonsurgical periodontal treatment can effectively reduce the serum level of CRP in these patients.

  10. Effects of Radial Reflector Composition on Core Reactivity and Peak Power

    Park, Sang Yoon; Lee, Kyung Hoon; Song, Jae Seung

    2007-10-01

    The effects of radial SA-240 alloy shroud on core reactivity and peak power are evaluated. The existence of radial SA-240 alloy shroud makes reflector water volume decrease, so the thermal absorption cross section of radial reflector is lower than without SA-240 alloy shroud case. Finally, the cycle length is increased from 788 EFPD to 845 EFPD and the peak power is decreased from 1.66 to 1.49. In the case of without SA-240 alloy shroud, a new core loading pattern search has been performed. For the guarantee of the same equivalent cycle length of with SA-240 alloy shroud case, the enrichment of U-235 should be increased from 4.22 w/o to 4.68 w/o. The nuclear key safety parameters of new core loading pattern have been calculated and recorded for the future

  11. Effects of Radial Reflector Composition on Core Reactivity and Peak Power

    Park, Sang Yoon; Lee, Kyung Hoon; Song, Jae Seung

    2007-10-15

    The effects of radial SA-240 alloy shroud on core reactivity and peak power are evaluated. The existence of radial SA-240 alloy shroud makes reflector water volume decrease, so the thermal absorption cross section of radial reflector is lower than without SA-240 alloy shroud case. Finally, the cycle length is increased from 788 EFPD to 845 EFPD and the peak power is decreased from 1.66 to 1.49. In the case of without SA-240 alloy shroud, a new core loading pattern search has been performed. For the guarantee of the same equivalent cycle length of with SA-240 alloy shroud case, the enrichment of U-235 should be increased from 4.22 w/o to 4.68 w/o. The nuclear key safety parameters of new core loading pattern have been calculated and recorded for the future.

  12. Effects of reactive element additions and sulfur removal on the oxidation behavior of FECRAL alloys

    Stasik, M.C.; Pettit, F.S.; Meier, G.H.; Smialek, J.L.

    1994-01-01

    The results of this study have shown that desulfurization of FeCrAl alloys by hydrogen annealing can result in improvements in cyclic oxidation comparable to that achieved by doping with reactive elements. Moreover, specimens of substantial thicknesses can be effectively desulfurized because of the high diffusivity of sulfur in bcc iron alloys. The results have also shown that there is less stress generation during the cyclic oxidation of Y-doped FeCrAl compared to Ti-doped or desulfurized FeCrAl. This indicates that the growth mechanism, as well as the strength of the oxide/alloy interface, influences the ultimate oxidation morphology and stress state which will certainly affect the length of time the alumina remains protective

  13. Reactive flow modeling of initial density effect on divergence JB-9014 detonation driving

    Yu, Xin; Huang, Kuibang; Zheng, Miao

    2016-06-01

    A serious of experiments were designed and the results were represented in this paper, in which 2mm thickness cooper shells were impacted by explosives named JB-9014 with different densities, and the surface velocities of the OFHC shells were measured. The comparison of experimental data shows the free surface velocity of the OFHC shell increase with the IHE density. Numerical modeling, which occupied phenomenological reactive flow rate model using the two-dimensional Lagrange hydrodynamic code, were carried out to simulate the above experiments, and empirical adjustments on detonation velocity and pressure and Pier Tang's adjustments on EOS of detonation products were both introduced in our numerical simulation work. The computational results agree well with that of experiments, and the numerical results with original parameters of products and the adjusted ones of JB-9014 could describe the density effect distinctly.

  14. Effects of prenatal stress and emotional reactivity of the mother on emotional and cognitive abilities in lambs.

    Coulon, Marjorie; Nowak, Raymond; Andanson, Stephane; Petit, Bérengère; Lévy, Frédéric; Boissy, Alain

    2015-07-01

    Consequences of prenatal stress on emotional reactivity and cognitive abilities in offspring are under-documented in precocial mammals. Here, we investigated to what extent emotional reactivity, judgment bias and spatial learning abilities of lambs are affected by chronic stress during late pregnancy and by their dams' emotional reactivity. The 20 highest-responsive (HR) and 20 lowest-responsive (LR) ewes from a population of 120 Romane ewes were selected according to their pre-mating reactivity to social isolation in a new environment. Over the final third of pregnancy, 10 HR ewes and 10 LR ewes were exposed daily to various unpredictable aversive events such as restraint, mixing groups and transport while the other 20 selected ewes were not. In a human and an object test, prenatally-stressed lambs were more fearful than control lambs, but the prenatal stress effect was moderated by the reactivity of the mothers: prenatally-stressed lambs from ewes with high emotional reactivity were more affected. Prenatally-stressed lambs did not perform as well as control lambs in a maze test and showed pessimistic-like judgment in a cognitive bias test. Prenatally-stressed lambs were thus characterized by a negative affective state with increased fear reactions and impaired cognitive evaluation. The development of negative moods could have long-lasting consequences on the coping strategies of the lambs in response to their rearing conditions. © 2015 Wiley Periodicals, Inc.

  15. Serum C-reactive protein concentration in preeclamptic women: Effect on pregnancy outcome

    Sharmin Sultana

    2016-07-01

    Full Text Available Background: Preeclampsia is a multisystem disorder of unknown etiology characterized by development of hyperten­sion to the extent of 140/90 mm of Hg or more with proteinuria after the 20th gestational week in a previously normoten­sive and non protein uric women. According to the National High blood presure Working group (NHBPEP and Ameri­can college of obstetricans and Gynecologiests (ACOG hypertension in pregnancy is defined as a diastolic blood pressure of 90 mm Hg or higher after 20 weeks of gestation in a woman with previously normal blood pressure (NHBPEP, 2000; ACOG, 2002. If the disease is allowed to progress to the HELLP syndrome or eclampsia, maternal morbidity and mortality increases. The majority of perinatal losses are related to placental insufficiency, which causes intrauterine growth retardation, prematurity associated with preterm delivery, or abruptio placentae. Objectives: This study tried to explore the effect of serum C reactive protein concentration in preeclamptic women and its effect on pregnancy outcome.Methods: This case control study included 60 third trimester pregnant women (30 normotensive and 30 preeclamptic who attended Department of Obstetrics and Gynaecology, BIRDEM and DMCH, during July 2009 and June 2010. Estimation of serum C reactive protein (CRP concentrations was done by liquid phase immunoprecipitation assay and turbulometry at DMC.Results: Mean (±SD age showed no significant difference between groups; however, BMI, SBP, DBP and CRP were significantly (P<0.001 high in case group. Gravidity and ANC showed no significant variation between groups. CRP concentration was significantly high case group. Gestational age was significantly low in case group resulting in higher preterm delivery. No significant variation was observed regarding fetal outcome; however, birth weight was significantly low and neonatal complication was also significantly high in case group.Conclusion: CRP concentration was high in

  16. Effect of nigella sativa seeds extract on serum c-reactive protein in albino rats

    Bashir, M.U.; Qureshi, H.

    2014-01-01

    C-reactive protein (CRP) is an acute phase protein. It predicts future risk of cardiovascular diseases. Different medicinal plants and their active ingredients possess the ability to reduce serum CRP levels and hence inflammatory disorders and cardiovascular diseases. In our study, ethanolic extract of Nigella sativa seeds was evaluated in albino rats for its possible effect on serum CRP levels. Objective: The objective of this study was to determine the effect of ethanolic extract of Nigella sativa seeds on an acute inflammatory biomarker/mediator, C-reactive protein (CRP) in albino rats. Study Design: Randomized controlled trial (RCT). Place and Duration of Study: Physiology Department, Services Institute of Medical Sciences (SIMS), Lahore; from September to November, 2009. Subjects and Methods: The study was carried out on 90 male albino rats. Five percent (5%) formalin in a dose of 50 meu1 was injected into sub-plantar surface of right hind paw of each rat to produce inflammation. The rats were randomly divided into three groups of thirty each. Group A was given normal saline (control); group B was given Nigella sativa seed extract; and group C received diclofenac sodium, as a reference drug. CRP levels in each group were measured from blood samples taken 25 hours after giving formalin. Results: The ethanolic extract of Nigella sativa seeds, given intraperitoneally, caused highly significant (p<0.001) reduction in serum CRP levels as compared to control group. The reduction in CRP levels by ethanolic extract of Nigella sativa was also significantly (p<0.05) more than that produced by diclofenac sodium. Conclusion: Our results suggest that Nigella sativa possesses ability to reduce serum CRP levels significantly, after production of artificial inflammation, in albino rats. (author)

  17. Effects of Ramadan fasting on platelet reactivity in diabetic patients treated with clopidogrel.

    Bouida, W; Baccouche, H; Sassi, M; Dridi, Z; Chakroun, T; Hellara, I; Boukef, R; Hassine, M; Added, F; Razgallah, R; Khochtali, I; Nouira, S

    2017-01-01

    The effects of Ramadan fasting (RF) on clopidogrel antiplatelet inhibition were not previously investigated. The present study evaluated the influence of RF on platelet reactivity in patients with high cardiovascular risk (CVR) in particular those with type 2 diabetes mellitus (DM). A total of 98 stable patients with ≥2 CVR factors were recruited. All patients observed RF and were taking clopidogrel at a maintenance dose of 75 mg. Clinical findings and serum lipids data were recorded before Ramadan (Pre-R), at the last week of Ramadan (R) and 4 weeks after the end of Ramadan (Post-R). During each patient visit, nutrients intakes were calculated and platelet reactivity assessment using Verify Now P2Y12 assay was performed. In DM patients, the absolute PRU changes from baseline were +27 ( p  = 0.01) and +16 ( p  = 0.02) respectively at R and Post-R. In addition, there was a significant increase of glycemia and triglycerides levels with a significant decrease of high-density lipoprotein. In non DM patients there was no significant change in absolute PRU values and metabolic parameters. Clopidogrel resistance rate using 2 cut-off PRU values (235 and 208) did not change significantly in DM and non DM patients. RF significantly decreased platelet sensitivity to clopidogrel in DM patients during and after Ramadan. This effect is possibly related to an increase of glycemia and serum lipids levels induced by fasting. Clinical Trials.gov NCT02720133. Registered 24 July 2014.Retrospectively registered.

  18. EFFECTS OF AGE AND ACUTE MUSCLE FATIGUE ON REACTIVE POSTURAL CONTROL IN HEALTHY ADULTS

    Papa, Evan V.; Foreman, K. Bo; Dibble, Lee E.

    2015-01-01

    BACKGROUND Falls can cause moderate to severe injuries such as hip fractures and head trauma in older adults. While declines in muscle strength and sensory function contribute to increased falls in older adults, skeletal muscle fatigue is often overlooked as an additional contributor to fall risk. The purpose of this investigation was to examine the effects of acute lower extremity muscle fatigue and age on reactive postural control in healthy adults. METHODS A sample of 16 individuals participated in this study (8 healthy older adults and 8 healthy young persons). Whole body kinematic and kinetic data were collected during anterior and posterior reproducible fall tests before (T0) and immediately after (T1) eccentric muscle fatiguing exercise, as well as after 15-minutes (T15) and 30-minutes (T30) of rest. FINDINGS Lower extremity joint kinematics of the stepping limb during the support (landing) phase of the anterior fall were significantly altered by the presence of acute muscle fatigue. Step velocity was significantly decreased during the anterior falls. Statistically significant main effects of age were found for step length in both fall directions. Effect sizes for all outcomes were small. No statistically significant interaction effects were found. INTERPRETATION Muscle fatigue has a measurable effect on lower extremity joint kinematics during simulated falls. These alterations appear to resolve within 15 minutes of recovery. The above deficits, coupled with a reduced step length, may help explain the increased fall risk in older adults. PMID:26351001

  19. Effects of age and acute muscle fatigue on reactive postural control in healthy adults.

    Papa, Evan V; Foreman, K Bo; Dibble, Leland E

    2015-12-01

    Falls can cause moderate to severe injuries such as hip fractures and head trauma in older adults. While declines in muscle strength and sensory function contribute to increased falls in older adults, skeletal muscle fatigue is often overlooked as an additional contributor to fall risk. The purpose of this investigation was to examine the effects of acute lower extremity muscle fatigue and age on reactive postural control in healthy adults. A sample of 16 individuals participated in this study (8 healthy older adults and 8 healthy young persons). Whole body kinematic and kinetic data were collected during anterior and posterior reproducible fall tests before (T0) and immediately after (T1) eccentric muscle fatiguing exercise, as well as after 15-min (T15) and 30-min (T30) of rest. Lower extremity joint kinematics of the stepping limb during the support (landing) phase of the anterior fall were significantly altered by the presence of acute muscle fatigue. Step velocity was significantly decreased during the anterior falls. Statistically significant main effects of age were found for step length in both fall directions. Effect sizes for all outcomes were small. No statistically significant interaction effects were found. Muscle fatigue has a measurable effect on lower extremity joint kinematics during simulated falls. These alterations appear to resolve within 15 min of recovery. The above deficits, coupled with a reduced step length, may help explain the increased fall risk in older adults. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Measurements and analyses on reactivity effects of absorber rods in a light-water moderated UO2 lattices

    Murakami, Kiyonobu; Miyoshi, Yoshinori; Hirose, Hideyuki; Suzaki, Takenori

    1985-03-01

    Reactivity effects and reactivity-interference effects of absorber rods were measured with a cylindrical core aiming to obtain bench-marks for verification of the calculational methods. The core consisted of 2.6 w/o enriched UO 2 fuel rods lattice of which water-to-fuel volume ratio was 1.83. In the experiment, the critical water levels were measured changing neutron absorber content of absorber rods and the distance between two absorber rods in the core center. Monte Calro codes KENO-IV and MULTI-KENO were used to calculate reactivity worthes of absorber rods. The calculational results of effective multiplication factors ranged from 0.978 to 0.999 for the 60 cases of critical cores with inserted absorber rods. The calculational results of absorber worthes agreed to the experimental results within twice of the standerd deviation accompanied with the Monte Calro calculation. (author)

  1. Effect of thiol reactive reagents and ionizing radiation on the permeability of erythrocyte membrane for non-electrolyte spin labels

    Gwozdzinski, K.

    1986-01-01

    The paper presents some results on the effect of PCMB and NEM on the transport of non-electrolyte spin labels: TEMPO and TEMPOL across non-irradiated and irradiated porcine erythrocyte. Irradiated erythrocytes exhibited increased inhibitory effect of thiol reactive compounds in the TEMPO and TEMPOL transport compared to non-irradiated erythrocytes. (orig.)

  2. The reactivation effect of pralidoxime in human blood on parathion and paraoxon–induced cholinesterase inhibition

    Mahvash Jafari

    2006-03-01

    Full Text Available In this investigation the reactivation of cholinesterases by pralidoxime in parathion and paraoxon intoxication in plasma and erythrocytes were studied. For this purpose, human plasma and erythrocytes were incubated with various concentrations of parathion (0.1-10 µM and paraoxon (0.03-0.3 µM at 37 oC for 10 min. Then, pralidoxime (10-300 µM was added to the samples and incubated for 10 min before cholinesterases assay. The results showed that effects of parathion and paraoxon were dose dependent. These agents inhibited more than 85% of butyrylcholinesterase (BChE and acetylcholinesterase (AChE activity and the inhibitory effect of paraoxon was 10 times more than parathion. BChE activity was significantly higher than the control at 100 µM of pralidoxime and it reduced inhibitory effects of parathion to less than 50% and of paraoxon to 42% of control. When pralidoxime (10 µM was added to erythrocytes, the inhibitory effects of two organophosphates were reduced to less than 15%. At higher concentrations of pralidoxime (>100 µM, both BChE and AChE activities were inhibited.

  3. Genetic Algorithms for Estimating Effective Parameters in a Lumped Reactor Model for Reactivity Predictions

    Marseguerra, Marzio; Zio, Enrico

    2001-01-01

    The control system of a reactor should be able to predict, in real time, the amount of reactivity to be inserted (e.g., by control rod movements and boron injection and dilution) to respond to a given electrical load demand or to undesired, accidental transients. The real-time constraint renders impractical the use of a large, detailed dynamic reactor code. One has, then, to resort to simplified analytical models with lumped effective parameters suitably estimated from the reactor data.The simple and well-known Chernick model for describing the reactor power evolution in the presence of xenon is considered and the feasibility of using genetic algorithms for estimating the effective nuclear parameters involved and the initial nonmeasurable xenon and iodine conditions is investigated. This approach has the advantage of counterbalancing the inherent model simplicity with the periodic reestimation of the effective parameter values pertaining to each reactor on the basis of its recent history. By so doing, other effects, such as burnup, are automatically taken into account

  4. Alpha-particles microbeam irradiation: impact of reactive oxygen species in bystander effect

    Hanot, M.

    2008-11-01

    Ionizing radiation-induced bystander effects arise in bystander cells that receive signals from directly irradiated cells. To date, free radicals are believed to play an active role in the bystander response, but this is incompletely characterized. To mark temporal and spatial impacts of bystander effect, we employed a precise α-particle microbeam to target a small fraction of sub-confluent osteoblastic cell cultures (MC3T3-E1). We identified the cellular membrane and mitochondria like two distinct places generating reactive oxygen species. The global oxidative stress observed after irradiation was significantly attenuated after filipin treatment, evidencing the pivotal role of membrane in MC3T3-E1 cells bystander response. To determine impact of bystander effect at a cell level, cellular consequences of this membrane-dependant bystander effect were then investigated. A variable fraction of the cell population (10 to 100%) was individually targeted. In this case, mitotic death and micronuclei yield both increased in bystander cells as well as in targeted cells demonstrating a role of bystander signals between irradiated cells in an autocrine or paracrine manner. Our results indicate a complex interaction of direct irradiation and bystander signals that lead to a membrane-dependant amplification of cell responses. (author)

  5. Effects of a Context Shift and Multiple Context Extinction on Reactivity to Alcohol Cues

    MacKillop, James; Lisman, Stephen A.

    2008-01-01

    Cue exposure treatment (CET) attempts to reduce the influence of conditioned substance cues on addictive behavior via prolonged cue exposure with response prevention (i.e., extinction), but has received only modest empirical support in clinical trials. This may be because extinction learning appears to be context dependent and a change in context may result in a return of conditioned responding (i.e., renewal), although this has received only limited empirical examination. The current study used a four-session laboratory analogue of CET to examine whether a change in context following three sessions of alcohol cue exposure with response prevention would result in renewal of conditioned responding. In addition, this study examined whether conducting extinction in multiple contexts would attenuate renewal of conditioned responding. In a one-way between-subjects design, 73 heavy drinkers (71% male) were randomized to three conditions: 1) single context extinction (extinction to alcohol cues in the same context for three sessions followed by a context shift at the fourth session); 2) multiple context extinction (extinction to alcohol cues in different contexts each day for all four sessions); and 3) pseudo-extinction control condition (exposure to neutral cues in the same context for three sessions followed by exposure to alcohol cues at the fourth session). The results revealed the predicted cue reactivity and extinction effects, but the hypotheses that a context shift would generate renewed cue reactivity and that multiple contexts would enhance extinction were not supported. Methodological aspects of the study and the need for parametric data on the context dependency of extinction to alcohol cues are discussed. PMID:18729687

  6. Doppler reactivity uncertainties and their effect upon a hypothetical LOF accident

    Malloy, D.J.

    1976-01-01

    The statistical uncertainties and the major methodological errors which contribute to the Doppler feedback uncertainty were reviewed and investigated. Improved estimates for the magnitudes of each type of uncertainty were established. The generally applied reactivity feedback methodology has been extended by explicitly treating the coupling effect which exists between the various feedback components. The improved methodology was specifically applied to the coupling of Doppler and sodium void reactivities. In addition, the description of the temperature dependence of the Doppler feedback has been improved by the use of a two-constant formula on a global and regional basis. Feedback and coupling coefficients are presented as a first comparison of the improved and the currently applied methods. Further, the energy release which results from hypothetical disassembly accidents was simulated with a special response surface in the parametric safety evaluation code PARSEC. The impact of the improved feedback methodology and of Doppler coefficient uncertainties was illustrated by the usual parametric relationship between available work-energy and the Doppler coefficient. The work-energy was calculated with the VENUS-II disassembly code and was represented as a response surface in PARSEC. Additionally, the probability distribution for available work-energy, which results from the statistical uncertainty of the Doppler coefficient, was calculated for the current and the improved feedback methodology. The improved feedback description yielded about a 16 percent higher average value for the work-energy. A substantially larger increase is found on the high-yield end of the spectrum: the probability for work-energy above 500 MJ was increased by about a factor of ten

  7. Analysis of reactivity feedback effects of void and temperature in the MAPLE-X10 reactor

    Carlson, P.A.; Heeds, W.; Shim, S.Y.; King, S.G.

    1992-07-01

    The methods used for evaluating the void and temperature reactivity coefficients for the MAPLE-X10 Reactor are described and factors used in estimating their accuracy are discussed. The report presents representative transient analysis results using the CATHENA thermalhydraulics code. The role of the reactivity coefficients and their precision is discussed. The results are reviewed in terms of their safety implications

  8. Various reactivity effects value for assuring fast reactor core inherent safety

    Belov, S.B.; Vasilyev, B.A.

    1991-01-01

    The paper presents the results of temperature and power reactivity feedback components calculations for fast reactors with different core volume when using oxide, carbide, nitride and metal fuel. Reactor parameters change in loss of flow without scram and transient over power without scram accidents was evaluated. The importance of various reactivity feedback components in restricting the consequences of these accidents has been analyzed. (author)

  9. The Ferrocyanide/Stabilized Carbon System, a New Class of High Rate, Long Cycle Life, Aqueous Electrolyte Batteries

    Huggins, R. A.

    2013-02-21

    Transient energy sources, such as wind and solar systems are getting increased attention. Their integration with the energy distribution grid requires methods for energy storage. The required characteristics of this type of storage are quite different from those for energy storage in portable devices. Size and weight are not so important. Instead, matters such as power, cost, calendar life, cycle life, and safety become paramount. A new family of hexacyanoferrate materials with the same open framework crystal structure as Prussian Blue has been recently developed with characteristics ideally suited for this type of application. Several monovalent cations can be rapidly and reversibly inserted into these materials, with very little crystallographic distortion, leading to high rates and long cycle lives. In addition, a new type of composite negative electrode material has been developed that has the rapid kinetics typical of carbon electrodes, but with a potential that varies little with the state of charge. The result is the development of a new battery system, the ferrocyanide/stabilized carbon, MHCF-SC, system. © 2013 The Electrochemical Society.

  10. Selective capture of cesium and thallium from natural waters and simulated wastes with copper ferrocyanide functionalized mesoporous silica

    Sangvanich, Thanapon [Biomedical Engineering, Oregon Health and Science University (OHSU) School of Medicine, Portland, OR 97239 (United States); Sukwarotwat, Vichaya; Wiacek, Robert J.; Grudzien, Rafal M.; Fryxell, Glen E.; Addleman, R. Shane; Timchalk, Charles [Pacific Northwest National Laboratory (PNNL), 902 Battelle Boulevard, Richland, WA 99352 (United States); Yantasee, Wassana, E-mail: yantasee@ohsu.edu [Biomedical Engineering, Oregon Health and Science University (OHSU) School of Medicine, Portland, OR 97239 (United States)

    2010-10-15

    Copper(II) ferrocyanide on mesoporous silica (FC-Cu-EDA-SAMMS{sup TM}) has been evaluated against iron(III) hexacyanoferrate(II) (insoluble Prussian Blue) for removing cesium (Cs{sup +}) and thallium (Tl{sup +}) from natural waters and simulated acidic and alkaline wastes. From pH 0.1-7.3, FC-Cu-EDA-SAMMS had greater affinities for Cs and Tl and was less affected by the solution pH, competing cations, and matrices. SAMMS also outperformed Prussian Blue in terms of adsorption capacities (e.g., 21.7 versus 2.6 mg Cs/g in acidic waste stimulant (pH 1.1), 28.3 versus 5.8 mg Tl/g in seawater), and rate (e.g., over 95 wt% of Cs was removed from seawater after 2 min with SAMMS, while only 75 wt% was removed with Prussian Blue). SAMMS also had higher stability (e.g., 2.5-13-fold less Fe dissolved from 2 to 24 h of contact time). In addition to environmental applications, SAMMS has great potential to be used as orally administered drug for limiting the absorption of radioactive Cs and toxic Tl in gastrointestinal tract.

  11. Preparation of polypyrrole/ferrocyanide films modified carbon paste electrode and its application on the electrocatalytic determination of ascorbic acid

    Raoof, Jahan-Bakhsh; Ojani, Reza; Rashid-Nadimi, Sahar

    2004-01-15

    Functionalized polypyrrole film were prepared by incorporation of (Fe(CN){sub 6}){sup 4-} as doping anion, during the electropolymerization of pyrrole onto a carbon paste electrode (CPE) in aqueous solution by using potentiostatic method. The electrochemical behavior of the (Fe(CN){sub 6}){sup 3-}/(Fe(CN){sub 6}){sup 4-} redox couple in polypyrrole was studied by cyclic voltammetry and double step potential chronoamperometry methods. In this study, an obvious surface redox reaction was observed and dependence of this reaction on the solution pH was illustrated. The electrocatalytic ability of polypyrrole/ferrocyanide films modified carbon paste electrode (Ppy/FCNMCPEs) was demonstrated by oxidation of ascorbic acid. It has been found that under optimum condition (pH 7.00), the oxidation of ascorbic acid at the surface of such electrode occurs at a potential about 540 mV less positive than unmodified carbon paste electrode. The kinetic parameters such as electron transfer coefficient, {alpha} and catalytic reaction rate constant, k{sub h}', were also determined by using various electrochemical approaches. The catalytic oxidation peak current showed a linear dependent on the ascorbic acid concentration and a linear calibration curve was obtained in the range of 4.5x10{sup -4} to 9.62x10{sup -3} M of ascorbic acid with a correlation coefficient of 0.9999. The detection limit (2{sigma}) was determined as 5.82x10{sup -5} M.

  12. Removal of radioactive caesium from low level radioactive waste (LLW) streams using cobalt ferrocyanide impregnated organic anion exchanger

    Valsala, T.P., E-mail: tpvalsala@yahoo.co.in [Waste Management Division, Bhabha Atomic Research Centre, Trombay 400 085 (India); Roy, S.C. [PREFRE Division, Bhabha Atomic Research Centre, Tarapur 401 502 (India); Shah, J.G. [Back End Technology Division, Bhabha Atomic Research Centre, Trombay 400 085 (India); Gabriel, J.; Raj, Kanwar [Waste Management Division, Bhabha Atomic Research Centre, Trombay 400 085 (India); Venugopal, V. [Radiochemistry Division, Bhabha Atomic Research Centre, Trombay 400 085 (India)

    2009-07-30

    The volumes of low level waste (LLW) generated during the operation of nuclear reactor are very high and require a concentration step before suitable matrix fixation. The volume reduction (concentration) is achieved either by co-precipitating technique or by the use of highly selective sorbents and ion exchange materials. The present study details the preparation of cobalt ferrocyanide impregnated into anion exchange resin and its evaluation with respect to removal of Cs in LLW streams both in column mode and batch mode operations. The Kd values of the prepared exchanger materials were found to be very good in actual reactor LLW solutions also. It was observed that the exchanger performed very well in the pH range of 3-9. A batch size of 6 g l{sup -1} of the exchanger was enough to give satisfactory decontamination for Cs in actual reactor LLW streams. The lab scale and pilot plant scale performance of the exchanger material in both batch mode and column mode operations was very good.

  13. Evaluation of ferrocyanide anion exchange resins regarding the uptake of Cs{sup +} ions and their regeneration

    Won, Hui Jun; Mooon, Jei Kwon; Jung, Chong Hun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Chung, Won Yang [Kangwon University, Chuncheon (Korea, Republic of)

    2008-10-15

    Ferrocyanide-anion exchange resin was prepared and the prepared ion exchange resins were tested on the ability to uptake Cs{sup +} ion. The prepared ion exchange resins were resin-KCoFC, resin-KNiFC, and resin-KCuFC. The three tested ion exchange resins showed ion exchange selectivity on the Cs{sup +} ion of the surrogate soil decontamination solution, and resin- KCoFC showed the best Cs{sup +} ion uptake capability among the tested ion exchange resins. The ion exchange behaviors were explained well by the modified Dubinin-Polanyi equation. A regeneration feasibility study of the spent ion exchange resins was also performed by the successive application of hydrogen peroxide and hydrazine. The desorption of the Cs{sup +} ion from the ion exchange resin satisfied the electroneutrality condition in the oxidation step; the desorption of the Fe{sup 2+} ion in the reduction step could also be reduced by adding the K{sup +} ion.

  14. Mediating role of stress reactivity in the effects of prenatal tobacco exposure on childhood mental health outcomes.

    Park, Aesoon; O'Malley, Stephanie S; King, Sarah L; Picciotto, Marina R

    2014-02-01

    Prenatal tobacco exposure, through maternal smoking during pregnancy, has been associated with adverse mental health outcomes in childhood. However, the mechanisms by which prenatal tobacco exposure compromises mental health later in life are unclear. We hypothesized that sensitized reactivity to stressful life events in early childhood mediates the effect of prenatal tobacco exposure on mental health outcomes in middle childhood, after accounting for earlier mental health outcomes. Data were from 12,308 mothers and their children drawn from the Avon Longitudinal Study of Parents and Children, a large prospective population-based study. Mothers' self-reports of smoking during pregnancy, mothers' ratings of their child's reactivity to stressful life events, and teachers' and mothers' ratings of the Strengths and Difficulties Questionnaire assessing 5 domains of mental health outcomes were measured. A positive association was found between prenatal tobacco exposure and stress reactivity between the ages of 2 and 6. In turn, stress reactivity was positively associated with peer (isolation), hyperactivity, conduct, and emotional problems (but not prosocial behaviors) between the ages of 7 and 11, after accounting for the mental health outcome at age 4 and other confounders. Heightened stress reactivity in preschool ages mediated the effect of prenatal tobacco exposure on adverse mental health outcomes between the ages of 7 and 11. Interventions to assist children exposed to tobacco smoke during gestation in coping with stressful life events may help mitigate psychiatric symptoms in this population.

  15. Parent emotion socialization and pre-adolescent's social and emotional adjustment: Moderating effects of autonomic nervous system reactivity.

    McQuade, Julia D; Breaux, Rosanna P

    2017-12-01

    This study examined whether measures of children's autonomic nervous system (ANS) reactivity to social stress moderated the effect of parent emotion socialization on children's social and emotional adjustment. Sixty-one children (9-13 years) completed a peer rejection task while their respiratory sinus arrhythmia reactivity (RSA-R) and skin conductance level reactivity (SCL-R) were assessed. Parents' report of supportive and non-supportive reactions to their child's negative emotions served as measures of emotion socialization. Measures of children's social and emotional adjustment included: teacher-rated peer rejection, aggression, and prosocial behavior and parent-rated aggressive/dysregulated behavior and emotion regulation skills. Measures of children's ANS reactivity moderated the effect of parent emotion socialization on children's adjustment. Supportive responses were more protective for children evidencing RSA augmentation whereas non-supportive responses were more detrimental for children evidencing low SCL-R. Thus children's ANS reactivity during social stress may represent a biological vulnerability that influences sensitivity to parent emotion socialization. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Lightning under water: Diverse reactive environments and evidence of synergistic effects for material treatment and activation

    Levchenko, Igor; Bazaka, Kateryna; Baranov, Oleg; Sankaran, R. Mohan; Nomine, Alexandre; Belmonte, Thierry; Xu, Shuyan

    2018-06-01

    This focused review aims to reveal and illustrate some unique features of processes triggered by high-density energy applied to liquids and gas-liquid interfaces and to highlight a wide spectrum of their technological applications capable of producing various advantageous effects, ranging from nanosynthesis to biological and medical applications. Plasma, electric discharges, laser, and ultrasound power effects were selected as representative examples of high-density energy and liquid interactions, yet the available possibilities are not limited by these quite different types of power and thus the reader could extrapolate the outlined features and effects to other kinds of powerful impacts. The basic physical mechanisms are briefly reviewed with the aim to familiarize the readers with the potential capabilities of high-density energy processes in liquids. These will be of direct interest to researchers tasked with the development, optimization, and characterization of processes and highly reactive environments for highly controlled transformation of matter in abiotic and biological systems. It could also be highly useful for under- and post-graduate students specializing in the related fields and general physical audience involved in various plasma, materials, energy conversion, and other concurrent research activities.

  17. The effects of stainless steel radial reflector on core reactivity for small modular reactor

    Kang, Jung Kil, E-mail: jkkang@email.kings.ac.kr; Hah, Chang Joo, E-mail: changhah@kings.ac.kr [KINGS, 658-91, Haemaji-ro, Seosaeng-myeon, Ulju-gun, Ulsan, 689-882 (Korea, Republic of); Cho, Sung Ju, E-mail: sungju@knfc.co.kr; Seong, Ki Bong, E-mail: kbseong@knfc.co.kr [KNFC, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of)

    2016-01-22

    Commercial PWR core is surrounded by a radial reflector, which consists of a baffle and water. Radial reflector is designed to reflect neutron back into the core region to improve the neutron efficiency of the reactor and to protect the reactor vessels from the embrittling effects caused by irradiation during power operation. Reflector also helps to flatten the neutron flux and power distributions in the reactor core. The conceptual nuclear design for boron-free small modular reactor (SMR) under development in Korea requires to have the cycle length of 4∼5 years, rated power of 180 MWth and enrichment less than 5 w/o. The aim of this paper is to analyze the effects of stainless steel radial reflector on the performance of the SMR using UO{sub 2} fuels. Three types of reflectors such as water, water/stainless steel 304 mixture and stainless steel 304 are selected to investigate the effect on core reactivity. Additionally, the thickness of stainless steel and double layer reflector type are also investigated. CASMO-4/SIMULATE-3 code system is used for this analysis. The results of analysis show that single layer stainless steel reflector is the most efficient reflector.

  18. Effect of the key mixture parameters on shrinkage of reactive powder concrete.

    Ahmad, Shamsad; Zubair, Ahmed; Maslehuddin, Mohammed

    2014-01-01

    Reactive powder concrete (RPC) mixtures are reported to have excellent mechanical and durability characteristics. However, such concrete mixtures having high amount of cementitious materials may have high early shrinkage causing cracking of concrete. In the present work, an attempt has been made to study the simultaneous effects of three key mixture parameters on shrinkage of the RPC mixtures. Considering three different levels of the three key mixture factors, a total of 27 mixtures of RPC were prepared according to 3(3) factorial experiment design. The specimens belonging to all 27 mixtures were monitored for shrinkage at different ages over a total period of 90 days. The test results were plotted to observe the variation of shrinkage with time and to see the effects of the key mixture factors. The experimental data pertaining to 90-day shrinkage were used to conduct analysis of variance to identify significance of each factor and to obtain an empirical equation correlating the shrinkage of RPC with the three key mixture factors. The rate of development of shrinkage at early ages was higher. The water to binder ratio was found to be the most prominent factor followed by cement content with the least effect of silica fume content.

  19. Effects of reactive oxygen species on cellular wall disassembly of banana fruit during ripening.

    Cheng, Guiping; Duan, Xuewu; Shi, John; Lu, Wangjin; Luo, Yunbo; Jiang, Weibo; Jiang, Yueming

    2008-07-15

    Fruit softening is generally attributed to cell wall disassembly. Experiments were conducted to investigate effects of various reactive oxygen species (ROS) on in vitro cellular wall disassembly of harvested banana fruit. The alcohol-extracted insoluble residue (AEIR) was obtained from the pulp tissues of banana fruit at various ripening stages and then used to examine the disassembly of cellular wall polysaccharides in the presence of superoxide anion (O2(-)), hydrogen peroxide (H2O2) or hydroxyl radical (OH) and their scavengers. The presence of OH accelerated significantly disassembly of cellular wall polysaccharides in terms of the increase in contents of total sugars released and uronic acid, and the decrease in molecular mass of soluble polysaccharides, using gel permeation chromatography. However, the treatment with H2O2 or O2(-) showed no significant effect on the disassembly of cellular wall polysaccharides. Furthermore, the degradation of the de-esterified AEIR was more susceptible to OH attack than the esterified AEIR. In addition, the effect of OH could be inhibited in the presence of OH scavenger. This study suggests that disassembly of cellular wall polysaccharides could be initiated by OH as the solublisation of the polysaccharides increased, which, in turn, accelerated fruit softening. Copyright © 2008 Elsevier Ltd. All rights reserved.

  20. Inhibitory Effects of Trapping Agents of Sulfur Drug Reactive Intermediates against Major Human Cytochrome P450 Isoforms

    Jasleen K. Sodhi

    2017-07-01

    Full Text Available In some cases, the formation of reactive species from the metabolism of xenobiotics has been linked to toxicity and therefore it is imperative to detect potential bioactivation for candidate drugs during drug discovery. Reactive species can covalently bind to trapping agents in in vitro incubations of compound with human liver microsomes (HLM fortified with β-nicotinamide adenine dinucleotide phosphate (NADPH, resulting in a stable conjugate of trapping agent and reactive species, thereby facilitating analytical detection and providing evidence of short-lived reactive metabolites. Since reactive metabolites are typically generated by cytochrome P450 (CYP oxidation, it is important to ensure high concentrations of trapping agents are not inhibiting the activities of CYP isoforms. Here we assessed the inhibitory properties of fourteen trapping agents against the major human CYP isoforms (CYP1A2, 2C9, 2C19, 2D6 and 3A. Based on our findings, eleven trapping agents displayed inhibition, three of which had IC50 values less than 1 mM (2-mercaptoethanol, N-methylmaleimide and N-ethylmaleimide (NEM. Three trapping agents (dimedone, N-acetyl-lysine and arsenite did not inhibit CYP isoforms at concentrations tested. To illustrate effects of CYP inhibition by trapping agents on reactive intermediate trapping, an example drug (ticlopidine and trapping agent (NEM were chosen for further studies. For the same amount of ticlopidine (1 μM, increasing concentrations of the trapping agent NEM (0.007–40 mM resulted in a bell-shaped response curve of NEM-trapped ticlopidine S-oxide (TSO-NEM, due to CYP inhibition by NEM. Thus, trapping studies should be designed to include several concentrations of trapping agent to ensure optimal trapping of reactive metabolites.

  1. The Synergistic Effect of Proteins and Reactive Oxygen Species on Electrochemical Behaviour of 316L Stainless Steel for Biomedical Applications

    Simionescu, N.; Benea, L.; Dumitrascu, V. M.

    2018-06-01

    The stainless steels, especially 316L type is the most used metallic biomaterials for biomedical applications due to their good biocompatibility, low price, excellent corrosion resistance, availability, easy processing and high strength. Due to these favorable properties 316L stainless steel has become the most attractive biomaterial for dental implants, stents and orthopedic implants. However an implant material in the human body is exposed to an action effect of other molecules, including proteins (such as albumin) and reactive oxygen species (such as hydrogen peroxide - H2O2 ) produced by bacteria and immune cells. In the literature there are few studies to follow the effect of proteins and reactive oxygen species on 316L stainless steel used as implant material and are still unclear. The degree of corrosion resistance is the first criterion in the use of a metallic biomaterial in the oral or body environment. The aim of this research work is to investigate the influence of proteins (albumin) and reactive oxygen species (H2O2 ) in combination, taking into account the synergistic effect of these two factors on 316L stainless steel. Albumin is present in the body near implants and reactive oxygen species could appear in inflammatory processes as well. The study shows that the presence of albumin and reactive species influences the corrosion resistance of 316L stainless steel in biological solutions. In this research work the corrosion behavior of 316L stainless steel is analyzed by electrochemical methods such as: open circuit potential (OCP), Electrochemical Impedance Spectroscopy (EIS). It was found that, the electrochemical results are in a good agreement with micro photographs taken before and after corrosion assays. The albumin and reactive oxygen species have influence on 316L stainless steel behavior.

  2. The effect of periodontal treatment on C-reactive protein: A clinical study.

    Kumar, Santosh; Shah, Samir; Budhiraja, Shilpa; Desai, Khushboo; Shah, Chirag; Mehta, Dhaval

    2013-07-01

    Chronic periodontitis in amultifactorial inflammatory disease which is caused by various microorganisms. Many studies have found close association between chronic periodontitis and C-reactive protein (CRP). CRPis an inflammatory marker which increases in all inflammatory condition. The present clinical study was designed to show the effect of periodontal treatment on the CRP levels of gingival crevicular fluid and to determine the effect of nonsurgical therapy in minimizing the CRP levels in chronic generalized periodontitis. Gingival crevicular fluid was collected using a micro capillary pipette that was hand calibrated at every 1 mm till 10 mm, from selected sites in the subjects on the 1st, 14th and 45th days. Decreased CRP levels of gingival crevicular fluid were observed at the end of the study. There was a 37% reduction in probing pocket depth and 45% gain in clinical attachment level and a reduction of about 57% after 14 days and 90% reduction of CRP levels in gingival crevicular fluid after 45 days. Thus, the results show that the presence of CRP level is more significant in gingival crevicular fluid and confirms the underlying inflammatory component of the disease activity in chronic periodontitis.

  3. Magnetoresistance and anomalous Hall effect of reactive sputtered polycrystalline Ti1 - XCrxN films

    Duan, Xiaofei

    2013-09-01

    The reactive-sputtered polycrystalline Ti1 - xCrxN films with 0.17 ≤ x ≤ 0.51 are ferromagnetic and at x = 0.47 the Curie temperature TC shows a maximum of ~ 120 K. The films are metallic at 0 ≤ x ≤ 0.47, while the films with x = 0.51 and 0.78 are semiconducting-like. The upturn of resistivity below 70 K observed in the films with 0.10 ≤ x ≤ 0.47 is from the effects of the electron-electron interaction and weak localization. The negative magnetoresistance (MR) of the films with 0.10 ≤ x ≤ 0.51 is dominated by the double-exchange interaction, while at x = 0.78, MR is related to the localized magnetic moment scattering at the grain boundaries. The scaling ρxyA/n ∝ ρxx2.19 suggests that the anomalous Hall effect in the polycrystalline Ti1 - xCrxN films is scattering-independent. © 2013 Elsevier B.V. All rights reserved.

  4. Insights into the Synergistic Effect of Fungi and Bacteria for Reactive Red Decolorization

    Dandan Zhou

    2014-01-01

    Full Text Available Bacterial contamination is a prevalent problem in fungal dye wastewater decolorization that prevents the development of this technology in practical engineering. New insight into the relationship between fungi and bacteria is given in terms of settleability, bioadsorption, and biodegradation, which all confirm their synergistic effect. Sterilization is implied to be not the only mechanism for fungi decolorization. When the fungi and bacteria isolated from the activated sludge were cocultured, fungi removed more than 70% of the reactive red through sole bioadsorption in 5 min and enhanced the settleability of the bacteria group from 7.7 to 18.4 in the aggregation index. Subsequently, the bacteria played a more significant role in dye biodegradation according to the ultraviolet-visible spectrum analysis. They further enhanced the decolorization efficiency to over 80% when cocultured with fungi. Therefore, the advanced bioadsorption and settleability of fungi, combined with the good dye biodegradation ability of bacteria, results in the synergistic effect of the coculture microorganisms.

  5. Effects of menadione, a reactive oxygen generator, on leukotriene secretion from RBL-2H3 cells.

    Kawamura, Fumio; Nakanishi, Mamoru; Hirashima, Naohide

    2010-01-01

    Reactive oxygen species (ROS) are produced in various cells and affect many biological processes. We previously reported that 2-methyl-1,4-naphtoquinone (menadione) inhibited Ca(2+) influx from the extracellular medium and exocytosis evoked by antigen stimulation in the mast cell line, RBL-2H3. Mast cells release various inflammatory mediators such as leukotrienes (LTs) and cytokines in addition to the exocytotic secretion of histamine. In this study, we investigated the effects of menadione on LT release in RBL-2H3. Treatment of RBL cells with menadione inhibited LTC(4) secretion induced by antigen stimulation. To elucidate the mechanism of this inhibition, we examined the effects of menadione on the activation process of 5-lipoxygenase that is responsible for the synthesis of LTs from arachidonic acid. Menadione did not affect the phosophorylation of mitogen activated protein (MAP) kinases, extracellular signal-regulated kinase (ERK) and p38, which regulates phosphorylation of 5-lipoxygenase. However, menadione inhibited the translocation of 5-lipoxygenase from the cytoplasm to the nuclear membrane. Together with the result that LT secretion was severely impaired in the absence of extracellular Ca2(2+), it is suggested that ROS produced by menadione inhibited LT secretion through impaired Ca2(2+) influx and 5-lipoxygenase translocation to the nuclear membrane.

  6. Effects of hyperstoichiometry and fission products on the electrochemical reactivity of UO2 nuclear fuel

    Betteridge, J.S.; Scott, N.A.M.; Shoesmith, D.W.; Bahen, L.E.; Hocking, W.H.; Lucuta, P.G.

    1997-03-01

    The effects of hyperstoichiometry and fission products on the electrochemical reactivity Of UO 2 nuclear fuel have been systematically investigated using cyclic voltammetry and the O 2 reduction reaction. Significant constraints are placed on the active-site model for O 2 reduction by the modest impact of bulk hyperstoichiometry. Formation of the U 4 O 9 derivative phase was associated with a marked increase in transient surface oxidation/reduction processes, which probably involve localized attack and might be fostered by tensile stresses induced during oxidation. Electrocatalytic reduction Of O 2 on simulated nuclear fuel (SIMFUEL) has been determined to increase progressively with nominal burnup and pronounced enhancement of H 2 O reduction has been observed as well. Substitution of uranium by lower-valence (simulated) fission products, which was formerly considered the probable cause for this behaviour, has now been shown to merely provide good electrical conductivity. Instead, the enhanced reduction kinetics for O 2 and H 2 O on SIMFUEL can be fully accounted for by noble metals, which segregate to the UO 2 grain boundaries as micron-sized particles, despite their low effective surface area. Apparent convergence of the electrochemical properties Of UO 2 and SIMFUEL through natural corrosion likely reflects evolution toward a common active surface. (author)

  7. Determination of reactivity coefficients from measurable effects of small external perturbations using a bank of Kalman filters

    Racz, A.

    1990-12-01

    The goal of this paper is to present a method for the determination of reactivity coefficients in a nuclear power reactor in operation. A method based on Kalman filtering technique and the Magill-Bogler test is proposed for the determination of reactivity coefficients from measured effects of small external perturbation introduced into a steady-state power reactor. Numerical experiments are presented to justify the procedure. A realistic problem is considered: the calculation of the control rod worth. Finally a possible way is given to check the goodness of the estimation. (author) 16 refs.; 4 figs

  8. Effects of loading reactivity at dynamic state on wave of neutrons in burst reactor

    Gao Hui; Liu Xiaobo; Fan Xiaoqiang

    2013-01-01

    Based on the point reactor model, the program for simulating the burst of reactors, including delay neutron, thermal feedback and reactivity of rod, was developed. The program proves to be suitable to burst reactor by experimental data. The program can describe the process of neutron-intensity change in burst reactors. With the program, the parameters of burst (wave of burst, power of peak and reactivity of reactor) under the condition of dynamic reactivity can be calculated. The calculated result demonstrates that the later the burst is initiated, the greater its power of peak and yield are and that the maximum yield coordinates with the yield under static state. (authors)

  9. Interactive effects of reactive nitrogen and climate change on US water resources

    Baron, J.; Bernhardt, E. S.; Finlay, J. C.; Chan, F.; Nolan, B. T.; Howarth, B.; Hall, E.; Boyer, E. W.

    2011-12-01

    Water resources and aquatic ecosystems are increasingly strained by withdrawals for agriculture and drinking water supply, nitrogen and other pollutant inputs, and climate change. We describe current and projected effects of the interactions of reactive nitrogen (N) and climate change on water resources of the United States. As perturbations to the N cycle intensify in a warmer less predictable climate, interactions will negatively affect the services we expect of our water resources. There are also feedbacks to the climate system itself through the production of greenhouse gases. We conclude: 1. Nitrogen concentrations will increase in the nation's waters from increased N loading and higher N mineralization rates. N export from terrestrial to aquatic ecosystems exhibits a high sensitivity to climate variations. 2. Consequences range from eutrophication and acidification, which reduce natural biodiversity and harm economically valuable fisheries, to adverse impacts on human health. 3. Extreme flood events have the potential to transport N rapidly long distances downstream from its source. 4. A recent national assessment found 67% of streams derived more than 37% of their total nitrate load from base flow often derived from groundwater. Long residence times for groundwater nitrate below agricultural fields may cause benefits from proper N management practices to take decades to be realized under current and future climates. 5. Streams, wetlands, rivers, lakes, estuaries and continental shelves are hotspots for denitrification. Maintenance of N removal capacity thus a critical component of eutrophication management under changing climate and land use conditions. 6. The amount of N inputs from fertilizer and manure use, human population, and deposition is tightly coupled with hydrology to influence the rates and proportion of N emitted to the atmosphere as N2O. About 20% of global N2O emissions come from groundwater, lakes, rivers, and estuaries; stream and wetland

  10. Live Video Classroom Observation: An Effective Approach to Reducing Reactivity in Collecting Observational Information for Teacher Professional Development

    Liang, Jiwen

    2015-01-01

    This paper examines the significance of live video classroom observations of teaching practice to reduce reactivity (the observer effect) so as to obtain more credible observational information for teacher professional development in a secondary school in the largest city in southern China. Although much has been discussed regarding the use of…

  11. Effects of Biomass Feedstock on the Yield and Reactivity of Soot from Fast Pyrolysis at High Temperatures

    Trubetskaya, Anna; Jensen, Peter A.; Glarborg, Peter

    This study investigated the effect of feedstock on the yield, nanostructure and reactivity of soot. Woody and herbaceous biomass were pyrolyzed at high heating rates and temperatures of 1250 and 1400°C in a drop tube furnace. The collected solid residues were structurally characterized by electro...

  12. Effects of Different Exercise Intensities with Isoenergetic Expenditures on C-Reactive Protein and Blood Lipid Levels

    Tsao, Te Hung; Yang, Chang Bin; Hsu, Chin Hsing

    2012-01-01

    We investigated the effects of different exercise intensities on C-reactive protein (CRP), and whether changes in CRP levels correlated with blood lipid levels. Ten men exercised at 25%, 65%, and 85% of their maximum oxygen consumption rates. Participants' blood was analyzed for CRP and blood lipid levels before and after the exercise sessions.…

  13. Effect of oral contraceptives and/or metformin on GLP-1 secretion and reactive hypoglycaemia in polycystic ovary syndrome

    Glintborg, Dorte; Mumm, Hanne; Holst, Jens Juul

    2017-01-01

    CONTEXT: Insulin resistance in polycystic ovary syndrome (PCOS) may increase the risk of reactive hypoglycaemia (RH) and decrease glucagon-like peptide-1 (GLP-1) secretion. The possible effects of treatment with oral contraceptives (OCP) and/or metformin on GLP-1 secretion and risk of RH in PCOS...

  14. The mediating effect of mindful non-reactivity in exposure-based cognitive behavior therapy for severe health anxiety.

    Hedman, Erik; Hesser, Hugo; Andersson, Erik; Axelsson, Erland; Ljótsson, Brjánn

    2017-08-01

    Exposure-based cognitive behavior therapy (CBT) has been shown to be effective in the treatment of severe health anxiety, but little is known about mediators of treatment effect. The aim of the present study was to investigate mindful non-reactivity as a putative mediator of health anxiety outcome using data from a large scale randomized controlled trial. We assessed mindful non-reactivity using the Five Facets Mindfulness Questionnaire-Non-Reactivity scale (FFMQ-NR) and health anxiety with the Short Health Anxiety Inventory (SHAI). Participants with severe health anxiety (N=158) were randomized to internet-delivered exposure-based CBT or behavioral stress management (BSM) and throughout the treatment, both the mediator and outcome were measured weekly. As previously reported, exposure-based CBT was more effective than BSM in reducing health anxiety. In the present study, latent process growth modeling showed that treatment condition had a significant effect on the FFMQ-NR growth trajectory (α-path), estimate=0.18, 95% CI [0.04, 0.32], p=.015, indicating a larger increase in mindful non-reactivity among participants receiving exposure-based CBT compared to the BSM group. The FFMQ-NR growth trajectory was significantly correlated with the SHAI trajectory (β-path estimate=-1.82, 95% CI [-2.15, -1.48], panxiety. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Investigation of Reactivity Feedback Mechanism of Axial and Radial Expansion Effect of Metal-Fueled Sodium-Cooled Fast Reactor

    Seong, Seung-Hwan; Choi, Chi-Woong; Jeong, Tae-Kyung; Ha, Gi-Seok

    2015-01-01

    The major inherent reactivity feedback models for a ceramic fuel used in a conventional light water reactor are Doppler feedback and moderator feedback. The metal fuel has these two reactivity feedback mechanisms previously mentioned. In addition, the metal fuel has two more reactivity feedback models related to the thermal expansion phenomena of the metal fuel. Since the metal fuel has a good capability to expand according to the temperature changes of the core, two more feedback mechanisms exist. These additional two feedback mechanism are important to the inherent safety of metal fuel and can make metal-fueled SFR safer than oxide-fueled SFR. These phenomena have already been applied to safety analysis on design extended condition. In this study, the effect of these characteristics on power control capability was examined through a simple load change operation. The axial expansion mechanism is induced from the change of the fuel temperature according to the change of the power level of PGSFR. When the power increases, the fuel temperatures in the metal fuel will increase and then the reactivity will decrease due to the axial elongation of the metal fuel. To evaluate the expansion effect, 2 cases were simulated with the same scenario by using MMS-LMR code developed at KAERI. The first simulation was to analyze the change of the reactor power according to the change of BOP power without the reactivity feedback model of the axial and radial expansion of the core during the power transient event. That is to say, the core had only two reactivity feedback mechanism of Doppler and coolant temperature

  16. Effect of exhaust gas recirculation (EGR) and multiple injections on diesel soot nano-structure and reactivity

    Rohani, Behzad; Bae, Choongsik

    2017-01-01

    -cylinder soot oxidation, and the consequent effect on the soot surface roughness. Results also show that the influence of injection strategy on the soot reactivity and VOF content tends to vanish as EGR is added.

  17. Smoking cue reactivity across massed extinction trials: negative affect and gender effects.

    Collins, Bradley N; Nair, Uma S; Komaroff, Eugene

    2011-04-01

    Designing and implementing cue exposure procedures to treat nicotine dependence remains a challenge. This study tested the hypothesis that gender and negative affect (NA) influence changes in smoking urge over time using data from a pilot project testing the feasibility of massed extinction procedures. Forty-three smokers and ex-smokers completed the behavioral laboratory procedures. All participants were over 17 years old, smoked at least 10 cigarettes daily over the last year (or the year prior to quitting) and had expired CO below 10 ppm at the beginning of the ~4-hour session. After informed consent, participants completed 45 min of baseline assessments, and then completed a series of 12 identical, 5-minute exposure trials with inter-trial breaks. Smoking cues included visual, tactile, and olfactory cues with a lit cigarette, in addition to smoking-related motor behaviors without smoking. After each trial, participants reported urge and negative affect (NA). Logistic growth curve models supported the hypothesis that across trials, participants would demonstrate an initial linear increase followed by a decrease in smoking urge (quadratic effect). Data supported hypothesized gender, NA, and gender×NA effects. Significant linear increases in urge were observed among high and low NA males, but not among females in either NA subgroup. A differential quadratic effect showed a significant decrease in urge for the low NA subgroup, but a non-significant decrease in urge in the high NA group. This is the first study to demonstrate gender differences and the effects of NA on the extinction process using a smoking cue exposure paradigm. Results could guide future cue reactivity research and exposure interventions for nicotine dependence. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. The effects of probiotic yoghurt on C-Reactive Protein in type 2 diabetic patients

    hanoyesadat Ejtahed

    2013-09-01

    Conclusion: Consumption of probiotic yoghurt improved C-Reactive Protein concentration in type 2 diabetic patients. Probiotic yoghurt consumption is recommended as auxiliary therapy in type 2 diabetic patients.

  19. Cortisol response mediates the effect of post-reactivation stress exposure on contextualization of emotional memories

    Bos, M.G.N.; Jacobs van Goethem, T.H.; Beckers, T.; Kindt, M.

    2014-01-01

    Retrieval of traumatic experiences is often accompanied by strong feelings of distress. Here, we examined in healthy participants whether post-reactivation stress experience affects the context-dependency of emotional memory. First, participants studied words from two distinctive emotional

  20. Contrasting neural effects of aging on proactive and reactive response inhibition

    Bloemendaal, Mirjam; Zandbelt, Bram; Wegman, Joost; Rest, van de O.; Cools, Roshan; Aarts, Esther

    2016-01-01

    Two distinct forms of response inhibition may underlie observed deficits in response inhibition in aging. We assessed whether age-related neurocognitive impairments in response inhibition reflect deficient reactive inhibition (outright stopping) or also deficient proactive inhibition

  1. Effect of viscosity, basicity and organic content of composite flocculant on the decolorization performance and mechanism for reactive dyeing wastewater

    Yuanfang Wang; Baoyu Gao; Qinyan Yue; Yah Wang

    2011-01-01

    A coagulation/flocculation process using the composite floceulant polyaluminum chloride-epichlorohydrin dimethylamine (PAC-EPI-DMA) was employed for the treatment of an anionic azo dye (Reactive Brilliant Red K-2BP dye).The effect of viscosity (η),basicity (B =[OH]/[Al]) and organic content (Wp) on the flocculation performance as well as the mechanism of PAC-EPI-DMA flocculant were investigated.The η was the key factor affecting the dye removal efficiency of PAC-EPI-DMA.PAC-EPI-DMA with an intermediate η (2400 mPa-sec) gave higher decolorization efficiency by adsorption bridging and charge neutralization due to the co-effect of PAC and EPI-DMA polymers.The Wp of the composite flocculant was a minor important factor for the flocculation.The adsorption bridging of PAC-EPI-DMA with η of 300 or 4300 mPa.sec played an important role with the increase of Wp,whereasthe charge neutralization of them was weaker with the increase of Wp.There was interaction between Wp and B on the removal of reactive dye.The composite flocculant with intermediate viscosity and organic content was effective for the treatment of reactive dyeing wastewater,which could achieve high reactive dye removal efficiency with low organic dosage.

  2. Effect of alpha irradiation on UO2 surface reactivity in aqueous media

    Jegou, C.; Muzeau, B.; Broudic, V.; Poulesquen, A.; Roudil, D.; Jorion, F.; Corbel, C.

    2005-01-01

    The option of direct disposal of spent nuclear fuel in a deep geological formation raises the need to investigate the long-term behavior of the UO 2 matrix in aqueous media subjected to α-β-γ radiation. The β-γ emitters account for most of the activity of spent fuel at the moment it is removed from the reactor, but diminish within a millennial time frame by over three orders of magnitude to less than the long-term activity. The latter persists over much longer time periods and must therefore be taken into account over a geological disposal time scale. Leaching experiments with solution renewal were carried out on UO 2 pellets doped with alpha emitters ( 238 Pu and 239 Pu) to quantify the impact of alpha irradiation on UO 2 matrix alteration. Three batches of doped UO 2 pellets with different alpha flux levels (3.30 x 10 4 , 3.30 x 10 5 , and 3.2 x 10 6 α cm -2 s -1 ) were studied. The results obtained in aerated and deaerated media immediately after sample annealing or interim storage in air provide a better understanding of the UO 2 matrix alteration mechanisms under alpha irradiation. Interim storage in air of UO 2 pellets doped with alpha emitters results in variations of the UO 2 surface reactivity, which depends on the alpha particle flux at the interface and on the interim storage duration. The variation in the surface reactivity and the greater uranium release following interim storage cannot be attributed to the effect of alpha radiolysis in aerated media since the uranium release tends toward the same value after several leaching cycles for the doped UO 2 pellet batches and spent fuel. Oxygen diffusion enhanced by alpha irradiation of the extreme surface layer and/or radiolysis of the air could account for the oxidation of the surface UO 2 to UO 2+x . However, leaching experiments performed in deaerated media after annealing the samples and preleaching the surface suggest that alpha radiolysis does indeed affect the dissolution, which varies with the

  3. Effect of alpha irradiation on UO{sub 2} surface reactivity in aqueous media

    Jegou, C.; Muzeau, B.; Broudic, V.; Poulesquen, A.; Roudil, D. [Commissariat a l' Energie Atomique (CEA), Rhone Valley Research Center, DIEC/SESC/LMPA, Bagnols-sur-Ceze (France); Jorion, F. [Commissariat a l' Energie Atomique (CEA), Rhone Valley Research Center, DRCP/SE2A/LEMA, Bagnols-sur-Ceze (France); Corbel, C. [Commissariat a l' Energie Atomique (CEA), Saclay Research Center, DSM/DRECAM/SCM, Gif sur Yvette (France)

    2005-07-01

    The option of direct disposal of spent nuclear fuel in a deep geological formation raises the need to investigate the long-term behavior of the UO{sub 2} matrix in aqueous media subjected to {alpha}-{beta}-{gamma} radiation. The {beta}-{gamma} emitters account for most of the activity of spent fuel at the moment it is removed from the reactor, but diminish within a millennial time frame by over three orders of magnitude to less than the long-term activity. The latter persists over much longer time periods and must therefore be taken into account over a geological disposal time scale. Leaching experiments with solution renewal were carried out on UO{sub 2} pellets doped with alpha emitters ({sup 238}Pu and {sup 239}Pu) to quantify the impact of alpha irradiation on UO{sub 2} matrix alteration. Three batches of doped UO{sub 2} pellets with different alpha flux levels (3.30 x 10{sup 4}, 3.30 x 10{sup 5}, and 3.2 x 10{sup 6} {alpha} cm{sup -2} s{sup -1}) were studied. The results obtained in aerated and deaerated media immediately after sample annealing or interim storage in air provide a better understanding of the UO{sub 2} matrix alteration mechanisms under alpha irradiation. Interim storage in air of UO{sub 2} pellets doped with alpha emitters results in variations of the UO{sub 2} surface reactivity, which depends on the alpha particle flux at the interface and on the interim storage duration. The variation in the surface reactivity and the greater uranium release following interim storage cannot be attributed to the effect of alpha radiolysis in aerated media since the uranium release tends toward the same value after several leaching cycles for the doped UO{sub 2} pellet batches and spent fuel. Oxygen diffusion enhanced by alpha irradiation of the extreme surface layer and/or radiolysis of the air could account for the oxidation of the surface UO{sub 2} to UO{sub 2+x}. However, leaching experiments performed in deaerated media after annealing the samples and

  4. Effect of cation exchange on the subsequent reactivity of lignite chars to steam. [108 references

    Hippo, E. J.; Walker, Jr., P. L.

    1977-03-01

    The purpose of this investigation is to determine the role which cations in coal play in the subsequent reactivity of chars. It is hoped that this investigation will aid in an understanding of the catalytic nature of inorganic constituents in coal during its gasification. It was found that increased heat treatment temperature decreased reactivity. The decrease in reactivity was shown to be due, at least in part, to the changes in the nature of the cation with increased heat treatment temperature. Reactivity was found to be a linear function of the amount of Ca(++) exchange on the demineralized coal. The constant utilization factor over the wide range of loadings employed indicated that below 800/sup 0/C the calcium did not markedly sinter. Potassium, sodium, and calcium-containing chars were found to be much more reactive than the iron and magnesium-containing chars. However, the iron and magnesium containing chars were more reactive than chars produced from the demineralized coal. The iron char was highly active at first but the iron phase was quickly oxidized to a comparatively unreactive ..gamma..Fe/sub 2/O/sub 3/-Fe/sub 3/O/sub 4/ phase. The state of magnesium was found to be MgO. Sodium and calcium were equally active as catalysts but not as active as potassium.

  5. Effect of doxazosin on stress reactivity and the ability to resist smoking.

    Verplaetse, Terril L; Weinberger, Andrea H; Oberleitner, Lindsay M; Smith, Kathryn Mz; Pittman, Brian P; Shi, Julia M; Tetrault, Jeanette M; Lavery, Meaghan E; Picciotto, Marina R; McKee, Sherry A

    2017-07-01

    Preclinical findings support a role for α1-adrenergic antagonists in reducing nicotine-motivated behaviors, but these findings have yet to be translated to humans. The current study evaluated whether doxazosin would attenuate stress-precipitated smoking in the human laboratory. Using a well-validated laboratory analogue of smoking-lapse behavior, this pilot study evaluated whether doxazosin (4 and 8 mg/day) versus placebo attenuated the effect of stress (vs neutral imagery) on tobacco craving, the ability to resist smoking and subsequent ad-libitum smoking in nicotine-deprived smokers ( n=35). Cortisol, adrenocorticotropin, norepinephrine, epinephrine, and physiologic reactivity were assessed. Doxazosin (4 and 8 mg/day vs placebo) decreased cigarettes per day during the 21-day titration period. Following titration, doxazosin (4 and 8 mg/day vs placebo) decreased tobacco craving. During the laboratory session, doxazosin (8 mg/day vs placebo) further decreased tobacco craving following stress versus neutral imagery. Doxazosin increased the latency to start smoking following stress, and reduced the number of cigarettes smoked. Dosage of 8 mg/day doxazosin increased or normalized cortisol levels following stress imagery and decreased cortisol levels following neutral imagery. These preliminary findings support a role for the noradrenergic system in stress-precipitated smoking behavior, and support further development of doxazosin as a novel pharmacotherapeutic treatment strategy for smoking cessation.

  6. Effects of Building‒roof Cooling on Flow and Distribution of Reactive Pollutants in street canyons

    Park, S. J.; Choi, W.; Kim, J.; Jeong, J. H.

    2016-12-01

    The effects of building‒roof cooling on flow and dispersion of reactive pollutants were investigated in the framework of flow dynamics and chemistry using a coupled CFD‒chemistry model. For this, flow characteristics were analyzed first in street canyons in the presence of building‒roof cooling. A portal vortex was generated in street canyon, producing dominant reverse and outward flows near the ground in all the cases. The building‒roof cooling increased horizontal wind speeds at the building roof and strengthened the downward motion near the downwind building in the street canyon, resultantly intensifying street canyon vortex strength. The flow affected the distribution of primary and secondary pollutants. Concentrations of primary pollutants such as NOx, VOC and CO was high near the upwind building because the reverse flows were dominant at street level, making this area the downwind region of emission sources. Concentration of secondary pollutant such as O3 was lower than the background near the ground, where NOX concentrations were high. Building‒roof cooling decreased the concentration of primary pollutants in contrasted to those under non‒cooling conditions. In contrast, building‒roof cooling increased O3 by reducing NO concentrations in urban street canyon compared to concentrations under non‒cooling conditions.

  7. Effects of combined radiofrequency radiation exposure on levels of reactive oxygen species in neuronal cells

    Kang, Kyoung Ah; Lee, Hyung Chul; Lee, Je-Jung

    2014-01-01

    The objective of this study was to investigate the effects of the combined RF radiation (837 MHz CDMA plus 1950 MHz WCDMA) signal on levels of intracellular reactive oxygen species (ROS) in neuronal cells. Exposure of the combined RF signal was conducted at specific absorption rate values of 2 W/kg of CDMA plus 2 W/kg of WCDMA for 2 h. Co-exposure to combined RF radiation with either H 2 O 2 or menadione was also performed. The experimental exposure groups were incubator control, sham-exposed, combined RF radiation-exposed with or without either H 2 O 2 or menadione groups. The intracellular ROS level was measured by flow cytometry using the fluorescent probe dichlorofluorescein diacetate. Intracellular ROS levels were not consistently affected by combined RF radiation exposure alone in a time-dependent manner in U87, PC12 or SH-SY5Y cells. In neuronal cells exposed to combined RF radiation with either H 2 O 2 or menadione, intracellular ROS levels showed no statically significant alteration compared with exposure to menadione or H 2 O 2 alone. These findings indicate that neither combined RF radiation alone nor combined RF radiation with menadione or H 2 O 2 influences the intracellular ROS level in neuronal cells such as U87, PC12 or SH-SY5Y. (author)

  8. Adolescent sympathetic activity and salivary C-reactive protein: The effects of parental behavior.

    Nelson, Benjamin W; Byrne, Michelle L; Simmons, Julian G; Whittle, Sarah; Schwartz, Orli S; Reynolds, Eric C; O'Brien-Simpson, Neil M; Sheeber, Lisa; Allen, Nicholas B

    2017-10-01

    This study utilized a novel multisystem approach to investigate the effect of observed parental behavior on the relationship between biological mechanisms associated with disease processes (i.e., autonomic physiology and immune response) among their adolescent children. Thirty-three adolescents (23 males), aged 11-13, and their parents participated in a laboratory session in which adolescents provided baseline measures of autonomic (sympathetic) activity, and adolescents and 1 parent participated in a laboratory based dyadic conflict resolution interaction task. This included 3 male parent/male adolescent dyads, 20 female parent/male adolescent dyads, 3 male parent/female adolescent dyads, and 7 female parent/female adolescent dyads. Approximately 3 years later, adolescents provided a salivary measure of C-Reactive Protein (sCRP) to index inflammation. Analyses revealed a positive association between sympathetic activity and sCRP, as well as a moderating role of positive parental behavior in this relationship, such that the association between sympathetic activity and sCRP was greater among adolescents whose parents displayed shorter duration of positive affect. Overall findings indicate parental behavior may influence the association between adolescent sympathetic activity and inflammatory processes. These findings have important implications for understanding the impact of psychosocial factors on biological mechanisms of disease. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  9. Effect of the nature of the surface on the reactivity of nanoporous silica under irradiation

    Le Caer, S.; Alam, M.S.; Chatelain, C.; Brunet, F.; Charpentier, T.; Renault, J.P.; Brodie-Linder, N.; Alba-Simionesco, C.

    2011-01-01

    Complete text of publication follows. Materials such as concrete, clays and zeolites which embed radioactive wastes adsorb in their pores significant amounts of water that can be decomposed under ionizing radiation leading to the formation of H 2 which is potentially explosive. It is well established that the H 2 production arises from chemi- or physi-sorbed OH groups at the surface of oxides. In this context, we have studied the behaviour of water confined in nanoporous silica. To distinguish the behavior of the two kinds of OH, we have performed different thermal treatments on SBA-15 materials prior to their irradiation. The IR analysis and H 2 measurements have proven that in the radiolysis of SBA-15 materials, silanol groups are only attacked when they are in the majority with respect to adsorbed water. However they are much less efficient at producing H 2 . The comparison between water content before and after electron irradiation and the corresponding H 2 production indicates that water desorption is the main route to adsorbed water loss. On the other hand, surface silanol groups are more susceptible to attack, leading to H 2 production when SBA-15 samples have undergone extensive thermal treatment. The surface of nanoporous glasses were then grafted using chloroaklyldimethylsilane. The effect of irradiation on these grafted surfaces was studied by means of mass spectrometry and NMR experiments. These different techniques reveal an original reactivity of the surface under irradiation.

  10. The Effects of Daily Co-Occurrence of Affect on Older Adults’ Reactivity to Health Stressors

    Ramsey, Jennifer L.; Neupert, Shevaun D.; Mroczek, Daniel K.; Spiro, Avron

    2015-01-01

    Objectives The present study examined age differences among older adults in the daily co-occurrence of affect and its potential role in buffering the negative effects of health stressors. Design Participants were from the Veterans Affairs Normative Aging Study (NAS) and included 249 young-old adults (age = 60–79 years, M=71.6) and 64 old-old adults (age = 80–89, M = 82.9) who completed questionnaires assessing stressors, physical health symptoms, and positive and negative affect on eight consecutive days. Results An independent samples t-test showed young-old and old-old adults did not significantly differ in their mean levels of daily co-occurrence of affect. The between-person relationships among stressors, health, and daily co-occurrence of affect revealed that neither stressors nor health were significantly related to daily co-occurrence of affect. However, results from a multilevel model revealed a three-way cross-level interaction (Health Stressor X Age Group X Co-Occurrence of Affect) where old-old adults with higher levels of co-occurrence of affect were less emotionally reactive to health stressors than young-old adults. Conclusion These findings provide support for the assertion that co-occurrence of affect functions in an adaptive capacity and highlight the importance of examining domain specific stressors. PMID:26518259

  11. The effects of daily co-occurrence of affect on older adults' reactivity to health stressors.

    Ramsey, Jennifer L; Neupert, Shevaun D; Mroczek, Daniel K; Spiro, Avron

    2016-01-01

    The present study examined age differences among older adults in the daily co-occurrence of affect and its potential role in buffering the negative effects of health stressors. Participants were from the Veterans Affairs Normative Aging Study and included 249 young-old adults (age = 60-79 years, M = 71.6) and 64 old-old adults (age = 80-89, M = 82.9) who completed questionnaires assessing stressors, physical health symptoms, and positive and negative affect for eight consecutive days. An independent samples t-test showed young-old and old-old adults did not significantly differ in their mean levels of daily co-occurrence of affect. The between-person relationships among stressors, health and daily co-occurrence of affect revealed that neither stressors nor health were significantly related to daily co-occurrence of affect. However, results from a multilevel model revealed a three-way cross-level interaction (health stressor × age group × co-occurrence of affect) where old-old adults with higher levels of co-occurrence of affect were less emotionally reactive to health stressors than young-old adults. These findings provide support for the assertion that co-occurrence of affect functions in an adaptive capacity and highlight the importance of examining domain-specific stressors.

  12. The Effect of Reactives Diluents to the Physical Properties of Acrylated Palm Oil Based Polyurethane Coatings

    Onn Munirah

    2016-01-01

    Full Text Available The development of polyurethane with hydroxyl access in a molecule leads to a new alternative of low toxicity green product. Palm oil is one of the major commodities in Malaysia. The potential of palm oil to be used as coatings raw material such as alkyd is limited due to low unsaturated side on fatty acid chains. To overcome this limitation, palm oil was modified through transesterification process to produce polyol. Acrylated isocyanate (urethane oligomer was then grafted onto polyol to produce polyurethane with vinylic ends. The polyurethane was formulated with different cross-linkers (reactive diluents and cured under UV radiation. The effect of three different diluents; monoacrylate, diacrylate and triacrylate on the properties of cured polymer were studied in this research. Fourier Transform Infrared (FTIR, Hydroxyl Value Titration, Gel Content, and Volatile Organic Compound (VOC were used for characterization. Physical testing performed were Pencil Hardness and Pull-Off Adhesion test. Novel palm oil-based polyurethane coatings have been found to have good properties with mono acrylate functionality.

  13. Effects of processing parameters on the properties of tantalum nitride thin films deposited by reactive sputtering

    Nazon, J.; Sarradin, J.; Flaud, V.; Tedenac, J.C. [Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, Place E. Bataillon, 34095 Montpellier Cedex 5 (France); Frety, N. [Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, Place E. Bataillon, 34095 Montpellier Cedex 5 (France)], E-mail: Nicole.Frety@univ-montp2.fr

    2008-09-22

    The effects of processing parameters on the properties of tantalum nitride thin films deposited by radio frequency reactive sputtering have been investigated. The influence of the N{sub 2} partial and (Ar + N{sub 2}) total gas pressures as well as the sputtering power on the microstructure and electrical properties is reported. Rising the N{sub 2} partial pressure, from 2 to 10.7%, induces a change in the composition of the {delta}-TaN phase, from TaN to TaN{sub 1.13}. This composition change is associated with a drastic increase of the electrical resistivity over a 7.3% N{sub 2} partial pressure. The total gas pressure is revealed to strongly affect the film microstructure since a variation in both composition and grain size is observed when the gas pressure rises from 6.8 to 24.6 Pa. When the sputtering power varied between 50 and 110 W, an increase of the grain size related to a decrease of the electrical resistivity is observed.

  14. Effects of metal ions on the reactivity and corrosion electrochemistry of Fe/FeS nanoparticles.

    Kim, Eun-Ju; Kim, Jae-Hwan; Chang, Yoon-Seok; Turcio-Ortega, David; Tratnyek, Paul G

    2014-04-01

    Nano-zerovalent iron (nZVI) formed under sulfidic conditions results in a biphasic material (Fe/FeS) that reduces trichloroethene (TCE) more rapidly than nZVI associated only with iron oxides (Fe/FeO). Exposing Fe/FeS to dissolved metals (Pd(2+), Cu(2+), Ni(2+), Co(2+), and Mn(2+)) results in their sequestration by coprecipitation as dopants into FeS and FeO and/or by electroless precipitation as zerovalent metals that are hydrogenation catalysts. Using TCE reduction rates to probe the effect of metal amendments on the reactivity of Fe/FeS, it was found that Mn(2+) and Cu(2+) decreased TCE reduction rates, while Pd(2+), Co(2+), and Ni(2+) increased them. Electrochemical characterization of metal-amended Fe/FeS showed that aging caused passivation by growth of FeO and FeS phases and poisoning of catalytic metal deposits by sulfide. Correlation of rate constants for TCE reduction (kobs) with electrochemical parameters (corrosion potentials and currents, Tafel slopes, and polarization resistance) and descriptors of hydrogen activation by metals (exchange current density for hydrogen reduction and enthalpy of solution into metals) showed the controlling process changed with aging. For fresh Fe/FeS, kobs was best described by the exchange current density for activation of hydrogen, whereas kobs for aged Fe/FeS correlated with electrochemical descriptors of electron transfer.

  15. Effects of methyl group on aromatic hydrocarbons on the nanostructures and oxidative reactivity of combustion-generated soot

    Guerrero Peñ a, Gerardo D.J.; Alrefaai, Mhd Maher; Yang, Seung Yeon; Raj, Abhijeet; Brito, Joaquin L.; Stephen, Samuel; Anjana, Tharalekshmy; Pillai, Vinu; Al Shoaibi, Ahmed; Chung, Suk-Ho

    2016-01-01

    The substituted and unsubstituted aromatic hydrocarbons, present in transportation fuels such as gasoline and diesel, are thought to be responsible for most of the soot particles produced during their combustion. However, the effects of the substituted alkyl groups on the aromatic hydrocarbons on their sooting tendencies, and on the physical and chemical properties of soot produced from them are not well understood. In this work, the effect of the presence of methyl groups on aromatic hydrocarbons on their sooting propensity, and on the oxidative reactivity, morphology, and chemical composition of soot generated from them in diffusion flames is studied using benzene, toluene, and m-xylene as fuels. Several experimental techniques including high resolution transmission electron microscopy and X-ray diffraction are used to identify the morphological changes in soot, whereas the elemental and thermo-gravimetric analyses, electron energy loss spectroscopy, and Fourier transform infrared spectroscopy are used to study the changes in its chemical properties and reactivity. The activation energies for soot oxidation are calculated at different conversion levels, and a trend in the reactivity of soots from benzene, toluene and m-xylene is reported. It is observed that the sizes of primary particles and graphene-like sheets, and the concentrations of aliphatics and oxygenated groups in soot particles decreased with the addition of methyl group(s) on the aromatic ring. The physicochemical changes in soot are found to support the oxidative reactivity trends. © 2016 The Combustion Institute

  16. Effects of methyl group on aromatic hydrocarbons on the nanostructures and oxidative reactivity of combustion-generated soot

    Guerrero Peña, Gerardo D.J.

    2016-07-23

    The substituted and unsubstituted aromatic hydrocarbons, present in transportation fuels such as gasoline and diesel, are thought to be responsible for most of the soot particles produced during their combustion. However, the effects of the substituted alkyl groups on the aromatic hydrocarbons on their sooting tendencies, and on the physical and chemical properties of soot produced from them are not well understood. In this work, the effect of the presence of methyl groups on aromatic hydrocarbons on their sooting propensity, and on the oxidative reactivity, morphology, and chemical composition of soot generated from them in diffusion flames is studied using benzene, toluene, and m-xylene as fuels. Several experimental techniques including high resolution transmission electron microscopy and X-ray diffraction are used to identify the morphological changes in soot, whereas the elemental and thermo-gravimetric analyses, electron energy loss spectroscopy, and Fourier transform infrared spectroscopy are used to study the changes in its chemical properties and reactivity. The activation energies for soot oxidation are calculated at different conversion levels, and a trend in the reactivity of soots from benzene, toluene and m-xylene is reported. It is observed that the sizes of primary particles and graphene-like sheets, and the concentrations of aliphatics and oxygenated groups in soot particles decreased with the addition of methyl group(s) on the aromatic ring. The physicochemical changes in soot are found to support the oxidative reactivity trends. © 2016 The Combustion Institute

  17. The effect of periodontal treatment on serum leptin, interleukin-6, and C-reactive protein.

    Shimada, Yasuko; Komatsu, Yasutaka; Ikezawa-Suzuki, Ikuyo; Tai, Hideaki; Sugita, Noriko; Yoshie, Hiromasa

    2010-08-01

    Previous studies suggest that periodontitis is closely related to obesity and metabolic syndrome. Leptin, a pleiotrophic hormone produced by adipose tissue, has been reported to be related to periodontitis. This study investigates the effects of periodontal treatment on the serum levels of leptin and other cytokines in patients with chronic periodontitis (CP). Serum samples were taken from 33 CP patients (22 non-smokers, 11 smokers) and 18 healthy subjects. The serum leptin, adiponectin, tumor necrosis factor-alpha, interleukin (IL)-6, and C-reactive protein (CRP) levels were measured before and after non-surgical periodontal treatment. Significant differences between healthy and CP patients were found in serum leptin, IL-6, and CRP levels (P = 0.0018, P = 0.0064, and P = 0.0095, respectively). The serum leptin level was associated with mean probing depth, mean clinical attachment level, mean alveolar bone loss, and body mass index. There were significant associations between serum leptin levels and IL-6 and CRP levels. After non-surgical periodontal treatment, serum leptin, IL-6, and CRP levels were significantly decreased (mean +/- SD before and after, P value, respectively: leptin, 8.02 +/- 5.5, 7.10 +/- 4.4, P = 0.015; IL-6, 1.73 +/- 1.02, 1.36 +/- 0.73, P = 0.048; and CRP, 802.0 +/- 1065, 491.2 +/- 479.3, P = 0.047). Periodontal treatment is effective in reducing serum leptin, IL-6, and CRP levels. The results suggest that leptin, IL-6, and CRP could be mediating factors that connect metabolic syndrome and periodontitis.

  18. Effects of cue-exposure treatment on neural cue reactivity in alcohol dependence: a randomized trial.

    Vollstädt-Klein, Sabine; Loeber, Sabine; Kirsch, Martina; Bach, Patrick; Richter, Anne; Bühler, Mira; von der Goltz, Christoph; Hermann, Derik; Mann, Karl; Kiefer, Falk

    2011-06-01

    In alcohol-dependent patients, alcohol-associated cues elicit brain activation in mesocorticolimbic networks involved in relapse mechanisms. Cue-exposure based extinction training (CET) has been shown to be efficacious in the treatment of alcoholism; however, it has remained unexplored whether CET mediates its therapeutic effects via changes of activity in mesolimbic networks in response to alcohol cues. In this study, we assessed CET treatment effects on cue-induced responses using functional magnetic resonance imaging (fMRI). In a randomized controlled trial, abstinent alcohol-dependent patients were randomly assigned to a CET group (n = 15) or a control group (n = 15). All patients underwent an extended detoxification treatment comprising medically supervised detoxification, health education, and supportive therapy. The CET patients additionally received nine CET sessions over 3 weeks, exposing the patient to his/her preferred alcoholic beverage. Cue-induced fMRI activation to alcohol cues was measured at pretreatment and posttreatment. Compared with pretreatment, fMRI cue-reactivity reduction was greater in the CET relative to the control group, especially in the anterior cingulate gyrus and the insula, as well as limbic and frontal regions. Before treatment, increased cue-induced fMRI activation was found in limbic and reward-related brain regions and in visual areas. After treatment, the CET group showed less activation than the control group in the left ventral striatum. The study provides first evidence that an exposure-based psychotherapeutic intervention in the treatment of alcoholism impacts on brain areas relevant for addiction memory and attentional focus to alcohol-associated cues and affects mesocorticolimbic reward pathways suggested to be pathophysiologically involved in addiction. Copyright © 2011 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  19. The synergistic effect of chemical carcinogens enhances Epstein-Barr virus reactivation and tumor progression of nasopharyngeal carcinoma cells.

    Fang, Chih-Yeu; Huang, Sheng-Yen; Wu, Chung-Chun; Hsu, Hui-Yu; Chou, Sheng-Ping; Tsai, Ching-Hwa; Chang, Yao; Takada, Kenzo; Chen, Jen-Yang

    2012-01-01

    Seroepidemiological studies imply a correlation between Epstein-Barr virus (EBV) reactivation and the development of nasopharyngeal carcinoma (NPC). N-nitroso compounds, phorbols, and butyrates are chemicals found in food and herb samples collected from NPC high-risk areas. These chemicals have been reported to be risk factors contributing to the development of NPC, however, the underlying mechanism is not fully understood. We have demonstrated previously that low dose N-methyl-N'-nitro-N-nitrosoguanidine (MNNG, 0.1 µg/ml) had a synergistic effect with 12-O-tetradecanoylphorbol-13-acetate (TPA) and sodium butyrate (SB) in enhancing EBV reactivation and genome instability in NPC cells harboring EBV. Considering that residents in NPC high-risk areas may contact regularly with these chemical carcinogens, it is vital to elucidate the relation between chemicals and EBV and their contributions to the carcinogenesis of NPC. In this study, we constructed a cell culture model to show that genome instability, alterations of cancer hallmark gene expression, and tumorigenicity were increased after recurrent EBV reactivation in NPC cells following combined treatment of TPA/SB and MNNG. NPC cells latently infected with EBV, NA, and the corresponding EBV-negative cell, NPC-TW01, were periodically treated with MNNG, TPA/SB, or TPA/SB combined with MNNG. With chemically-induced recurrent reactivation of EBV, the degree of genome instability was significantly enhanced in NA cells treated with a combination of TPA/SB and MNNG than those treated individually. The Matrigel invasiveness, as well as the tumorigenicity in mouse, was also enhanced in NA cells after recurrent EBV reactivation. Expression profile analysis by microarray indicates that many carcinogenesis-related genes were altered after recurrent EBV reactivation, and several aberrations observed in cell lines correspond to alterations in NPC lesions. These results indicate that cooperation between chemical carcinogens can

  20. Effect of two doses of carbamylated allergoid extract of dust mite on nasal reactivity.

    Scalone, G; Compalati, E; Bruno, M E; Mistrello, G

    2013-11-01

    Background and Objective. Single SLIT studies with native allergen extracts support a dose-response effect for clinical and immunological outcomes. Conversely for carbamylated allergoids this dose-response effects is less evident, likely because the threshold for efficacy is more easily reached through the enhanced bioavailability of the extract consequent to the selective chemical modification. Thus this pilot study investigates the dose-response effect on nasal specific reactivity and safety of two unusual doses of carbamylated allergoid in patients mono-sensitized to house dust mites. Methods. A prospective open randomized study involved 6-65 year-old Italian patients with clinically relevant sensitization to house dust mites and positive response to nasal provocation challenge. Monomeric carbamylated allergoid was delivered once daily at the dose of 1000 AU or 2000 AU from June to September 2009, during the lowest level of mites exposure. Primary outcomes were the change of the threshold of allergen concentration for a positive nasal provocation test (NPT) before and after the treatment and the product safety. Secondary outcome was the change  in the mean percentage fall of peak nasal inspiratory flow (PNIF) following nasal challenge. Results. Thirty-four patients were enrolled. Fifteen in group 1 and 14 in group 2 concluded the study. After 12 weeks all patients treated in group 1 and all but one in group 2 showed an increase in the threshold dose provoking a positive NPT. Those with no symptoms onset with the highest dose delivered were 80% in group 1 and 78.6% in group 2 (p=0.92). From first to second challenge, the mean percentage fall of PNIF  was reduced with no statistical difference between groups (p=0.95), and with no difference between the final mean percentage falls (p=0.65). No serious adverse reactions occurred and the frequency of events, all mild, was similar in the two groups. Conclusions. Twelve weeks of carbamylated sublingual allergoid

  1. Ultraviolet enhanced reactivation of a human virus: effect of delayed infection

    Bockstahler, L.E.; Lytle, C.D.; Stafford, J.E.; Haynes, K.F.

    1976-01-01

    The ability of UV-irradiated herpes simplex virus to form plaques was examined in monolayers of CV-1 monkey kidney cells preexposed to UV radiation at different intervals before virus assay. From analysis of UV reactivation (Weigle reactivation) curves it was found that as the interval between cell UV irradiation (0-20 J/m 2 ) and initiation of the virus assay was increased over a period of five days, (1) the capacity of the cells to support unirradiated virus plaque formation, which was decreased immediately following UV exposure of the monolayers, increased and returned to approximately normal levels within five days, and (2) at five days an exponential increase was observed in the relative plaque formation of irradiated virus as a function of UV dose to the monolayers. For high UV fluence (20 J/m 2 ) to the cells, the relative plaque formation by the UV-irradiated virus at five days was about 10-fold higher than that obtained from assay on unirradiated cells. This enhancement in plaque formation is interpreted as a delayed expression of Weigle reactivation. The amount of enhancement resulting from this delayed reactivation was several fold greater than that produced by the Weigle reactivation which occurred when irradiated herpes virus was assayed immediately following cell irradiation

  2. Contribution to the study of recoil species produced by potassium ferrocyanide neutron irradiation; Contribution a l'etude de la reactivite des especes de recul dans le ferrocyanure de potassium irradie aux neutrons thermiques

    Meriadec Vernier de Byans, B. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-04-01

    The chemical species produced by potassium ferrocyanide neutron irradiation were separated and identified. The study of their behaviour upon thermal annealing has allowed to establish a scheme of reaction as well as a kinetic treatment of the data. Activation energies are determined in different conditions and the effects of radiation dose, oxygen and water of crystallisation upon the activation energies were studied. Preliminary E.S.R. data and its relevance to the decomposition process is also discussed. (authors) [French] On a separe et identifie les differentes especes chimiques produites par irradiation neutronique de ferrocyanure de potassium. L'etude de leur comportement au cours du recuit thermique a permis l'application de differentes cinetiques et l'etablissement d'un schema de reaction. On a deterrmine la valeur des energies d'activation dans differentes conditions de recuit ainsi que l'influence de la dose de radiations, de l'oxygene et de l'eau de cristallisation sur ces energies. Une serie de mesures de resonance paramagnetique electronique a complete cette etude. (auteurs)

  3. Development and validation of calculation schemes dedicated to the interpretation of small reactivity effects for nuclear data improvement

    Gruel, A.

    2011-01-01

    Reactivity measurements by the oscillation technique, as those performed in the Minerve reactor, enable to access various neutronic parameters on materials, fuels or specific isotopes. Usually, expected reactivity effects are small, about ten pcm at maximum. Then, the modeling of these experiments should be very precise, to obtain reliable feedback on the pointed parameters. Especially, calculation biases should be precisely identified, quantified and reduced to get precise information on nuclear data. The goal of this thesis is to develop a reference calculation scheme, with well quantified uncertainties, for in-pile oscillation experiments. In this work are presented several small reactivity calculation methods, based on deterministic and/or stochastic calculation codes. Those method are compared thanks to a numerical benchmark, against a reference calculation. Three applications of these methods are presented here: a purely deterministic calculation with exact perturbation theory formalism is used for the experimental validation of fission product cross sections, in the frame of reactivity loss studies for irradiated fuel; an hybrid method, based on a stochastic calculation and the exact perturbation theory is used for the readjustment of nuclear data, here 241 Am; and a third method, based on a perturbative Monte Carlo calculation, is used in a conception study. (author) [fr

  4. Effect of magnesium on reactive oxygen species production in the thigh muscles of broiler chickens.

    Liu, Y X; Guo, Y M; Wang, Z

    2007-02-01

    1. The objective of the present study was to investigate the effect of magnesium (Mg) on reactive oxygen species (ROS) production in the thigh muscles of broiler chickens. A total of 96 1-d-old male Arbor Acre broiler chickens were randomly allocated into two groups, fed either on low-Mg or control diets containing about 1.2 g/kg or 2.4 g Mg/kg dry matter. 2. The low-Mg diet significantly increased malondialdehyde (MDA) concentration and decreased glutathione (GSH) in the thigh muscles of broiler chickens. ROS production in the thigh muscle homogenate was significantly higher in the low-Mg group than in the control group. Compared with the control, muscle Mg concentration of broiler chickens from the low-Mg group decreased by 9.5%. 3. Complex II and III activities of the mitochondrial electron transport chain in broilers on low-Mg diet increased by 23 and 35%, respectively. Significant negative correlations between ROS production and the activities of mitochondrial electron transport chain (ETC) complexes were observed. 4. The low-Mg diet did not influence contents of iron (Fe) or calcium (Ca) in the thigh muscles of broiler chickens and did not influence unsaturated fatty acid composition (except C18:2) in the thigh muscles. 5. A low-Mg diet decreased Mg concentration in the thigh muscles of broiler chickens and then induced higher activities of mitochondrial ETC, consequently increasing ROS production. These results suggest that Mg modulates the oxidation-anti-oxidation system of the thigh muscles at least partly through affecting ROS production.

  5. Protective Effects of BDNF against C-Reactive Protein-Induced Inflammation in Women

    Nicole Noren Hooten

    2015-01-01

    Full Text Available Background. Since high sensitivity C-reactive protein (hsCRP is predictive of cardiovascular events, it is important to examine the relationship between hsCRP and other inflammatory and oxidative stress markers linked to cardiovascular disease (CVD etiology. Previously, we reported that hsCRP induces the oxidative stress adduct 8-oxo-7,8-dihydro-2′deoxyguanosine (8-oxodG and that these markers are significantly associated in women. Recent data indicates that brain-derived neurotrophic factor (BDNF may have a role in CVD. Methods and Results. We examined BDNF levels in 3 groups of women that were age- and race-matched with low (3–20 mg/L, and high (>20 mg/L hsCRP (n=39 per group and found a significant association between hsCRP, BDNF, and 8-oxodG. In African American females with high hsCRP, increases in BDNF were associated with decreased serum 8-oxodG. This was not the case in white women where high hsCRP was associated with high levels of BDNF and high levels of 8-oxodG. BDNF treatment of cells reduced CRP levels and inhibited CRP-induced DNA damage. Conclusion. We discovered an important relationship between hsCRP, 8-oxodG, and BDNF in women at hsCRP levels >3 mg/L. These data suggest that BDNF may have a protective role in counteracting the inflammatory effects of hsCRP.

  6. The effect of chronic nitric oxide inhibition on vascular reactivity and blood pressure in pregnant rats

    Nilton Hideto Takiuti

    1999-09-01

    Full Text Available CONTEXT: The exact mechanism involved in changes in blood pressure and peripheral vascular resistance during pregnancy is unknown. OBJECTIVE:To evaluate the importance of endothelium-derivated relaxing factor (EDRF and its main component, nitric oxide, in blood pressure and vascular reactivity in pregnant rats. DESIGN: Clinical trial in experimentation animals. SETTING: University laboratory of Pharmacology. SAMPLE: Female Wistar rats with normal blood pressure, weight (152 to 227 grams and age (90 to 116 days. INTERVENTION: The rats were divided in to four groups: pregnant rats treated with L-NAME (13 rats; pregnant control rats (8 rats; virgin rats treated with L-NAME (10 rats; virgin control rats (12 rats. The vascular preparations and caudal blood pressure were obtained at the end of pregnancy, or after the administration of L-NAME in virgin rats. MAIN MEASUREMENTS: The caudal blood pressure and the vascular response to acetylcholine in pre-contracted aortic rings, both with and without endothelium, and the effect of nitric oxide inhibition, Nw-L-nitro-arginine methyl-ester (L-NAME, in pregnant and virgin rats. The L-NAME was administered in the drinking water over a 10-day period. RESULTS: The blood pressure decreased in pregnancy. Aortic rings of pregnant rats were more sensitive to acetylcholine than those of virgin rats. After L-NAME treatment, the blood pressure increased and relaxation was blocked in both groups. The fetal-placental unit weight of the L-NAME group was lower than that of the control group. CONCLUSION: Acetylcholine-induced vasorelaxation sensitivity was greater in pregnant rats and that blood pressure increased after L-NAME administration while the acetylcholine-induced vasorelaxation response was blocked.

  7. Effect of chemical degradation on fluxes of reactive compounds – a study with a stochastic Lagrangian transport model

    J. Rinne

    2012-06-01

    Full Text Available In the analyses of VOC fluxes measured above plant canopies, one usually assumes the flux above canopy to equal the exchange at the surface. Thus one assumes the chemical degradation to be much slower than the turbulent transport. We used a stochastic Lagrangian transport model in which the chemical degradation was described as first order decay in order to study the effect of the chemical degradation on above canopy fluxes of chemically reactive species. With the model we explored the sensitivity of the ratio of the above canopy flux to the surface emission on several parameters such as chemical lifetime of the compound, friction velocity, stability, and canopy density. Our results show that friction velocity and chemical lifetime affected the loss during transport the most. The canopy density had a significant effect if the chemically reactive compound was emitted from the forest floor. We used the results of the simulations together with oxidant data measured during HUMPPA-COPEC-2010 campaign at a Scots pine site to estimate the effect of the chemistry on fluxes of three typical biogenic VOCs, isoprene, α-pinene, and β-caryophyllene. Of these, the chemical degradation had a major effect on the fluxes of the most reactive species β-caryophyllene, while the fluxes of α-pinene were affected during nighttime. For these two compounds representing the mono- and sesquiterpenes groups, the effect of chemical degradation had also a significant diurnal cycle with the highest chemical loss at night. The different day and night time loss terms need to be accounted for, when measured fluxes of reactive compounds are used to reveal relations between primary emission and environmental parameters.

  8. Fuel density effect on parameter of reactivity coefficient of the Innovative Research Reactor core

    Rokhmadi; Tukiran S

    2013-01-01

    The multipurpose of research reactor utilization make many countries build the new research reactor. Trend of this reactor for this moment is multipurpose reactor type with a compact core to get high neutron flux at the low or medium level of power. The research reactor in Indonesia right now is already 25 year old. Therefor, it is needed to design a new research reactor as a alternative called it innovative research reactor (IRR) and then as an exchanger for old research reactor. The aim of this research is to complete RRI core design data as a requirement for design license. Calculation done is to get the RRI core reactivity coefficients with 5 x 5 core configuration and 20 MW of power, has more than 40 days cycle of length. The RRI core reactivity coefficient calculation is done for new U-"9Mo-Al fuel with variation of densities. The calculation is done by using WIMSD-5B and BATAN-FUEL computer codes. The result of calculation for conceptual design showed that the equilibrium RRI core with 5 x 5 configuration, 450 g, 550 g and 700 g of fuel loadings have negative reactivity coefficients of fuel temperature, moderator temperature, void fraction and density of moderator but the values of the reactivities are very variation. This results has met the safety criteria for RRI core conceptual design. (author)

  9. The effect of interfacial modification on the properties of reactively processed polypropylene/clay nanocomposites

    Khunová, V.; Kelnar, Ivan; Liauw, C. M.; Lukáč, P.

    2011-01-01

    Roč. 18, č. 4 (2011), s. 357-370 ISSN 0927-6440 Institutional research plan: CEZ:AV0Z40500505 Keywords : nanocomposite * reactive processing * polyolefins Subject RIV: JI - Composite Materials Impact factor: 0.438, year: 2011

  10. Effect of the selective adsorption on the reactive scattering process of molecular beams from stepped surfaces

    Garcia, N.

    1977-01-01

    An indicative proposal which may explain the diffusion of incident atomic beams scattered by a crystal surface is made in terms of the selective adsorption mechanism. In this sense, the stepped metallic surfaces present characteristics which enhance the displacements and the lifetimes of the beams on the surface. This may be important for increasing the exchange reactive scattering of molecules from crystal surfaces

  11. The Predictive Effect of Big Five Factor Model on Social Reactivity ...

    The study tested a model of providing a predictive explanation of Big Five Factor on social reactivity among secondary school adolescents of Cross River State, Nigeria. A sample of 200 students randomly selected across 12 public secondary schools in the State participated in the study (120 male and 80 female). Data ...

  12. A carnosine intervention study in overweight human volunteers: bioavailability and reactive carbonyl species sequestering effect

    Regazzoni, Luca; de Courten, Barbora; Garzon, Davide; Altomare, Alessandra; Marinello, Cristina; Jakubova, Michaela; Vallova, Silvia; Krumpolec, Patrik; Carini, Marina; Ukropec, Jozef; Ukropcova, Barbara; Aldini, Giancarlo

    2016-06-01

    Carnosine is a natural dipeptide able to react with reactive carbonyl species, which have been recently associated with the onset and progression of several human diseases. Herein, we report an intervention study in overweight individuals. Carnosine (2 g/day) was orally administered for twelve weeks in order to evaluate its bioavailability and metabolic fate. Two carnosine adducts were detected in the urine samples of all subjects. Such adducts are generated from a reaction with acrolein, which is one of the most toxic and reactive compounds among reactive carbonyl species. However, neither carnosine nor adducts have been detected in plasma. Urinary excretion of adducts and carnosine showed a positive correlation although a high variability of individual response to carnosine supplementation was observed. Interestingly, treated subjects showed a significant decrease in the percentage of excreted adducts in reduced form, accompanied by a significant increase of the urinary excretion of both carnosine and carnosine-acrolein adducts. Altogether, data suggest that acrolein is entrapped in vivo by carnosine although the response to its supplementation is possibly influenced by individual diversities in terms of carnosine dietary intake, metabolism and basal production of reactive carbonyl species.

  13. Hepatotoxic effects of fenofibrate in spontaneously hypertensive rats expressing human C-reactive protein

    Škop, V.; Trnovská, J.; Oliyarnyk, O.; Marková, I.; Malínská, H.; Kazdová, L.; Zídek, Václav; Landa, Vladimír; Mlejnek, Petr; Šimáková, Miroslava; Kůdela, M.; Pravenec, Michal; Šilhavý, Jan

    2016-01-01

    Roč. 65, č. 6 (2016), s. 891-899 ISSN 0862-8408 R&D Projects: GA MZd(CZ) NT14325 Institutional support: RVO:67985823 Keywords : fenofibrate * rosuvastatin * C-reactive protein * transgenic * spontaneously hypertensive rat * inflammation * hepatotoxic Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 1.461, year: 2016

  14. Magnetoresistance and anomalous Hall effect of reactive sputtered polycrystalline Ti1 - XCrxN films

    Duan, Xiaofei; Mi, Wenbo; Guo, Zaibing; Bai, Haili

    2013-01-01

    The reactive-sputtered polycrystalline Ti1 - xCrxN films with 0.17 ≤ x ≤ 0.51 are ferromagnetic and at x = 0.47 the Curie temperature TC shows a maximum of ~ 120 K. The films are metallic at 0 ≤ x ≤ 0.47, while the films with x = 0.51 and 0

  15. Ultralow concentrations of bupivacaine exert anti-inflammatory effects on inflammation-reactive astrocytes

    Block, Linda; Jörneberg, Per; Björklund, Ulrika; Westerlund, Anna; Biber, Björn; Hansson, Elisabeth

    2013-01-01

    Bupivacaine is a widely used, local anesthetic agent that blocks voltage-gated Na+ channels when used for neuro-axial blockades. Much lower concentrations of bupivacaine than in normal clinical use, bupivacaine exerts an influence on the Ca2+ signaling and interleukin-1β (IL-1β) secretion in inflammation-reactive astrocytes when used at ultralow concentrations, bupivacaine interacts with the opioid-, 5-hydroxytryptamine- (5-HT) and glutamate-receptor systems. With respect to the μ-opioid- and 5-HT-receptor systems, bupivacaine restored the inflammation-reactive astrocytes to their normal non-inflammatory levels. With respect to the glutamate-receptor system, bupivacaine, in combination with an ultralow concentration of the μ-opioid receptor antagonist naloxone and μ-opioid receptor agonists, restored the inflammation-reactive astrocytes to their normal non-inflammatory levels. Ultralow concentrations of bupivacaine attenuated the inflammation-induced upregulation of IL-1β secretion. The results indicate that bupivacaine interacts with the opioid-, 5-HT- and glutamate-receptor systems by affecting Ca2+ signaling and IL-1β release in inflammation-reactive astrocytes. These results suggest that bupivacaine may be used at ultralow concentrations as an anti-inflammatory drug, either alone or in combination with opioid agonists and ultralow concentrations of an opioid antagonist. PMID:24083665

  16. Effect of reactive monomer on PS-b-P2VP film with UV irradiation

    Kim, H. J.; Shin, D. M.

    2012-03-01

    Poly(styrene-b-2-vinyl pyridine) (PS-b-P2VP) lamellar film which is hydrophobic block hydrophilic polyelectrolyte block polymer of 52 kg/mol -b- 57 kg/mol and PS-b-P2VP film with reactive monomer (RM257) were prepared for photonic gel films. The lamellar stacks, which is alternating layer of hydrophilic and hydrophobic part of PS-b-P2VP. We reported about the influence of reactive monomer on those photonic gel films. Added reactive monomer photonic gel film had higher absorbance than pure photonic gel films. And band gaps of the lamellar films shifted by the time of UV light irradiation. That Photonic gel films were measured with the UV spectrophotometer. As a result the photonic gel film with reactive monomer had more clear color. The lamellar films were swollen by DI water, Ethyl alcohol (aq) and calcium carbonate solution. Since the domain spacing of dried photonic gel films were not showing any color in visible wavelength. The band gap of the lamellar films were drastically shifted to longer wavelength swollen by calcium carbonate solution (absorbance peak 565nm-->617nm). And the lamellar films were shifted to shorter wave length swollen by ethanol (absorbance peak 565nm-->497nm). So each Photonic gel film showed different color.

  17. Effect of reactive atmosphere on pulsed laser deposition of hydroxyapatite thin films

    Mroz, W.; Jedynski, M.; Hoffman, J.; Jelínek, Miroslav; Major, B.; Prokopiuk, A.; Szymanski, Z.

    2007-01-01

    Roč. 59, - (2007), s. 720-723 ISSN 1742-6588 Grant - others:PBZ-KBN(PL) 100/TO8/2003 and 0028/TOO/2005/29 Institutional research plan: CEZ:AV0Z10100522 Keywords : PLD * hydroxyapatite * reactive atmosphere * thin layers Subject RIV: BM - Solid Matter Physics ; Magnetism

  18. Effect of Fast Pyrolysis Conditions on Structural Transformation and Reactivity of Herbaceous Biomasses at High Temperatures

    Trubetskaya, Anna; Jensen, Anker D.; Jensen, Peter Arendt

    of organic and inorganic matter on the char structural transformations. The results indicate no influence of the free radicals on char reactivity and burnout. The formation of free radicals in fast pyrolysis is related to the differences in the ash composition, namely presence of K+ ions in the wheat straw...

  19. Reactive nitrogen in the environment and its effect on climate change

    Erisman, J.W.; Galloway, J.N.; Seitzinger, S.; Bleeker, A.; Butterbach-Bahl, K.

    2011-01-01

    Humans have doubled levels of reactive nitrogen in circulation, largely as a result of fertilizer application and fossil fuel burning. This massive alteration of the nitrogen cycle affects climate, food security, energy security, human health and ecosystem services. Our estimates show that nitrogen

  20. Effect of Aerobic Exercise on C-reatine reactive protein and Index of ...

    Lamina

    Subjects in the interval group involved in interval training (60-79% maximum heart ... of exercise training on C-reactive protein, erectile function index, SBP, DBP ... patients with cardiac disease have shown a high .... low intensity of between 35-59% of their HR max .... Aging and Body Composition Study (Health ABC) (40),.

  1. Parenting and Children's Distress Reactivity during Toddlerhood: An Examination of Direction of Effects

    Scaramella, Laura V.; Sohr-Preston, Sara L.; Mirabile, Scott P.; Robison, Sarah D.; Callahan, Kristin L.

    2008-01-01

    During early childhood, harsh and emotionally negative parent-child exchanges are expected to increase children's risk for developing later conduct problems. The present study examined longitudinal associations between the quality of parenting responses and children's distress reactivity during children's second year of life. Forty-seven…

  2. In Search of an Effective in vivo Reactivator for Organophosphorus Nerve Agent-Inhibited Acetylcholinesterase in the Central Nervous System

    2012-01-01

    nerve agents, such as sarin (GB), cyclosarin (GF), and VX, are potent inhibitors of the enzyme cholinesterase (ChE). Their toxic effects are due to...three nerve agents. Keywords: acetylcholinesterase; brain; cholinesterase inhibition; cholinesterase reactivation; cyclosarin; diacetylmonoxime...attributed, at least in part, to nuclophilic impedance [Ekstrom et al., 2006a; b; Hoskovcova et al., 2007]. Other AChE- inhibitors , such as soman, become

  3. Degradation of reactive blue 13 using hydrodynamic cavitation: Effect of geometrical parameters and different oxidizing additives.

    Rajoriya, Sunil; Bargole, Swapnil; Saharan, Virendra Kumar

    2017-07-01

    Decolorization of reactive blue 13 (RB13), a sulphonated azo dye, was investigated using hydrodynamic cavitation (HC). The aim of research article is to check the influence of geometrical parameters (total flow area, the ratio of throat perimeter to its cross-sectional area, throat shape and size, etc.) and configuration of the cavitating devices on decolorization of RB13 in aqueous solution. For this purpose, eight cavitating devices i.e. Circular and slit venturi, and six orifice plates having different flow area and perimeter were used in the present work. Initially, the effects of various operating parameters such as solution pH, initial dye concentration, operating inlet pressure and cavitation number on the decolorization of RB13 have been investigated, and the optimum operating conditions were found. Kinetic analysis revealed that the decolorization and mineralization of RB13 using HC followed first order reaction kinetics. Almost 47% decolorization of RB13 was achieved using only HC with slit venturi as a cavitating device at an optimum inlet pressure of 0.4MPa and pH of the solution as 2.0. It has been found that in case of orifice plates, higher decolorization rate of 4×10 -3 min -1 was achieved using orifice plate 2 (OP2) which is having higher flow area and perimeter (α=2.28). The effect of process intensifying agents (hydrogen peroxide and ferrous sulphate) and different gaseous additives (oxygen and ozone) on the extent of decolorization of RB13 were also examined. Almost 66% decolorization of RB13 was achieved using HC combined with 2Lmin -1 of oxygen and in combination with ferrous sulphate (1:3). Nearly 91% decolorization was achieved using HC combined with H 2 O 2 at an optimum molar ratio (dye:H 2 O 2 ) of 1:20 while almost complete decolorization was observed in 15min using a combination of HC and ozone at 3gh -1 ozone feed rate. Maximum 72% TOC was removed using HC coupled with 3gh -1 ozone feed rate. Copyright © 2017 Elsevier B.V. All

  4. On the Effects of Reactive Oxygen Species and Nitric Oxide on Red Blood Cell Deformability

    Lukas Diederich

    2018-05-01

    Full Text Available The main function of red blood cells (RBCs is the transport of respiratory gases along the vascular tree. To fulfill their task, RBCs are able to elastically deform in response to mechanical forces and, pass through the narrow vessels of the microcirculation. Decreased RBC deformability was observed in pathological conditions linked to increased oxidative stress or decreased nitric oxide (NO bioavailability, like hypertension. Treatments with oxidants and with NO were shown to affect RBC deformability ex vivo, but the mechanisms underpinning these effects are unknown. In this study we investigate whether changes in intracellular redox status/oxidative stress or nitrosation reactions induced by reactive oxygen species (ROS or NO may affect RBC deformability. In a case-control study comparing RBCs from healthy and hypertensive participants, we found that RBC deformability was decreased, and levels of ROS were increased in RBCs from hypertensive patients as compared to RBCs from aged-matched healthy controls, while NO levels in RBCs were not significantly different. To study the effects of oxidants on RBC redox state and deformability, RBCs from healthy volunteers were treated with increasing concentrations of tert-butylhydroperoxide (t-BuOOH. We found that high concentrations of t-BuOOH (≥ 1 mM significantly decreased the GSH/GSSG ratio in RBCs, decreased RBC deformability and increased blood bulk viscosity. Moreover, RBCs from Nrf2 knockout (KO mice, a strain genetically deficient in a number of antioxidant/reducing enzymes, were more susceptible to t-BuOOH-induced impairment in RBC deformability as compared to wild type (WT mice. To study the role of NO in RBC deformability we treated RBC suspensions from human volunteers with NO donors and nitrosothiols and analyzed deformability of RBCs from mice lacking the endothelial NO synthase (eNOS. We found that NO donors induced S-nitrosation of the cytoskeletal protein spectrin, but did not affect

  5. DMol3/COSMO-RS prediction of aqueous solubility and reactivity of selected Azo dyes: Effect of global orbital cut-off and COSMO segment variation

    Wahab, OO

    2018-01-01

    Full Text Available Aqueous solubility and reactivity of four azo dyes were investigated by DMol3/COSMO-RS calculation to examine the effects of global orbital cut-off and COSMO segment variation on the accuracies of theoretical solubility and reactivity. The studied...

  6. The mediation reaction between the external couple Ferri/Ferrocyanide and Os(II) bipyridile poly-vinylpyridile films coated onto glassy carbon electrodes

    Ybarra, Gabriel; Moina, Carlos [Centro de Investigacion sobre Electrodeposicion y Procesos Superficiales, Instituto Nacional de Tecnologia Industrial, CC 157, 1650 San Martin (Argentina); Florit, M. Ines [INIFTA, Facultad de Ciencias Exactas, UNLP, Suc. 4, CC 16, 1900 La Plata (Argentina); Posadas, Dionisio [INIFTA, Facultad de Ciencias Exactas, UNLP, Suc. 4, CC 16, 1900 La Plata (Argentina)], E-mail: dposadas@inifta.unlp.edu.ar

    2008-05-30

    The oxidation-reduction of the Ferri/Ferrocyanide couple in solution onto modified glassy carbon Rotating Disk Electrodes (RDE) covered by Os(II) bipyridile poly-vinylpyridile (OsBPP) polymer was studied at room temperature. Steady state polarization curves were carried out as a function of the rotation speed, the polymer thickness and the concentration of redox centers within the polymer. This system has the characteristic that the formal redox potentials of both the external redox couple (E{sup 0}'(Fe(CN){sub 6}{sup 3-/4-}) = + 0.225 V vs. SCE) and the mediator polymer (E{sup 0}'(OsBPP) = 0.260 V vs. SCE) lie very close. It is demonstrated that diffusion of the Ferri/Ferrocyanide inside the polymer can be ruled out. Since the processes of charge transfer at the metal/polymer and the mediating reaction are fast, the experimental results can be interpreted in terms of a kinetics in which the charge transport in the polymer or the diffusion in the solution may be the rate determining step, according to the experimental conditions. A simple model is considered that allows interpreting the experimental results quantitatively. Application of this model allows the determination of the diffusion coefficient of the electrons within the film, D{sub e} {approx} 10{sup -10} cm{sup 2} s{sup -1}.

  7. [Effects of Reactive Jump Training in Handball Players Regarding Jump Height and Power Development in the Triceps Surae Muscle].

    Rensing, N; Westermann, A; Möller, D; von Piekartz, H

    2015-12-01

    Studies have shown changes in the technical and physical demands in modern handball. The game has increased considerably in speed, power and dynamics. Jump training has, therefore, become ever more important in the training of the athletes. These developments contribute to the fact that handball is now one of the most injury-prone types of sport, with the lower extremities being most frequently affected. Reactive jump training is not only used in training by now, but also increasingly in injury prevention. The aim of this study was to investigate the effectiveness of reactive jump training with handball players. 21 regional league handball players were randomly divided into an intervention group (n = 12) and a control group (n = 9). The intervention group completed a six-week reactive jump training programme while the control group went through a non-specific training programme. Jump height (squat and counter movement jump), isokinetic and isometric maximum power as well as muscle activity served as measuring parameters. A comparison of the intervention and control groups revealed that the reactive jump training led to significant improvements in jump height. The isometric and isokinetic maximum power measurements and the electromyographic activities of the triceps surae muscle demonstrated an improvement in the values within the intervention group. However, this improvement was not significant compared with the control group. Likewise both jumps correlated with the muscle activity of the soleus muscle as shown by electromyography. A moderate correlation was noticed between the isokinetic maximum power measurement and the electromyographic activity of the soleus and gastrocnemius medialis muscles. Furthermore, the correlations of the isometric and isokinetic maximum power meas-urements resulted in a strong correlation coefficient. This study revealed a significant increase in jump height after reactive jump training. There was no significant difference in

  8. Neurofeedback Effects on Evoked and Induced EEG Gamma Band Reactivity to Drug-related Cues in Cocaine Addiction

    Horrell, Timothy; El-Baz, Ayman; Baruth, Joshua; Tasman, Allan; Sokhadze, Guela; Stewart, Christopher; Sokhadze, Estate

    2010-01-01

    Introduction Preoccupation with drug and drug-related items is a typical characteristic of cocaine addicted individuals. It has been shown in multiple accounts that prolonged drug use has a profound effect on the EEG recordings of drug addicts when compared to controls during cue reactivity tests. Cue reactivity refers to a phenomenon in which individuals with a history of drug abuse exhibit excessive psychophysiological responses to cues associated with their drug of choice. One of the aims of this pilot study was to determine the presence of an attentional bias to preferentially process drug-related cues using evoked and induced gamma reactivity measures in cocaine addicts before and after biobehavioral treatment based on neurofeedback. Another aim was to show that central SMR amplitude increase and frontal theta control is possible in an experimental outpatient drug users group over 12 neurofeedback sessions. Method Ten current cocaine abusers participated in this pilot research study using neurofeedback combined with Motivational Interviewing sessions. Eight of them completed all planned pre- and post –neurofeedback cue reactivity tests with event-related EEG recording and clinical evaluations. Cue reactivity test represented a visual oddball task with images from the International Affective Picture System and drug-related pictures. Evoked and induced gamma responses to target and non-target drug cues were analyzed using wavelet analysis. Results Outpatient subjects with cocaine addiction completed the biobehavioral intervention and successfully increased SMR while keeping theta practically unchanged in 12 sessions of neurofeedback training. The addition of Motivational Interviewing helped retain patients in the study. Clinical evaluations immediately after completion of the treatment showed decreased self-reports on depression and stress scores, and urine tests collaborated reports of decreased use of cocaine and marijuana. Effects of neurofeedback resulted

  9. Effects of gamma irradiations on reactive pulsed laser deposited vanadium dioxide thin films

    Madiba, I.G., E-mail: madibagiven@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Empa, Swiss Federal Laboratories Materials Science and Technology, CH-8600 Dübendorf (Switzerland); Émond, N.; Chaker, M. [Institut National de la Recherche Scientifique (INRS),1650 Blvd. Lionel-Boulet, Varennes, Québec J3X1S2 (Canada); Thema, F.T. [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); Tadadjeu, S.I. [iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); Department of Electrical, Electronics and Computer Engineering, French South African Institute of Technology/Cape Peninsula University of Technology, Bellville campus, PO Box 1906, Bellville, 7530 (South Africa); Muller, U.; Zolliker, P. [Empa, Swiss Federal Laboratories Materials Science and Technology, CH-8600 Dübendorf (Switzerland); Braun, A. [ETH Zurich, Swiss Federal Institute of Technology, CH-8057, Zurich (Switzerland); Empa, Swiss Federal Laboratories Materials Science and Technology, CH-8600 Dübendorf (Switzerland); Kotsedi, L. [iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); and others

    2017-07-31

    Highlights: • Synthesis of VO{sub 2} thin films by Reactive pulsed laser deposition has been achieved. • Properties VO{sub 2} remain mainly unaffected when subjected to gamma ray doses similar to those encountered during space missions. • The long range crystal structure of VO{sub 2} remains intact upon irradiation on different doses up to 100 kGy. • XPS reveals a shift from V{sup 4+} to V{sup 5+} oxidation state upon irradiation, due to the frenkel pair formation on the surface. • Irradiated films show the characteristic SMT of VO{sub 2}, although the electrical and optical properties are slightly affected. - Abstract: Vanadium oxide films are considered suitable coatings for various applications such as thermal protective coating of small spacecrafts because of their thermochromic properties. While in outer space, such coating will be exposed to cosmic radiations which include γ-rays. To study the effect of these γ-rays on the coating properties, we have deposited vanadium dioxide (VO{sub 2}) films on silicon substrates and subjected them to extensive γ-irradiations with typical doses encountered in space missions. The prevalent crystallographic phase after irradiation remains the monoclinic VO{sub 2} phase but the films preferential orientation shifts to lower angles due to the presence of disordered regions caused by radiations. Raman spectroscopy measurements also evidences that the VO{sub 2} structure is slightly affected by gamma irradiation. Indeed, increasing the gamma rays dose locally alters the crystalline and electronic structures of the films by modifying the V–V inter-dimer distance, which in turns favours the presence of the VO{sub 2} metallic phase. From the XPS measurements of V2p and O1s core level spectra, an oxidation of vanadium from V{sup 4+} towards V{sup 5+} is revealed. The data also reveal a hydroxylation upon irradiation which is corroborated by the vanishing of a low oxidation state peak near the Fermi energy in the

  10. Coupling a system code with computational fluid dynamics for the simulation of complex coolant reactivity effects

    Bertolotto, D.

    2011-11-01

    The current doctoral research is focused on the development and validation of a coupled computational tool, to combine the advantages of computational fluid dynamics (CFD) in analyzing complex flow fields and of state-of-the-art system codes employed for nuclear power plant (NPP) simulations. Such a tool can considerably enhance the analysis of NPP transient behavior, e.g. in the case of pressurized water reactor (PWR) accident scenarios such as Main Steam Line Break (MSLB) and boron dilution, in which strong coolant flow asymmetries and multi-dimensional mixing effects strongly influence the reactivity of the reactor core, as described in Chap. 1. To start with, a literature review on code coupling is presented in Chap. 2, together with the corresponding ongoing projects in the international community. Special reference is made to the framework in which this research has been carried out, i.e. the Paul Scherrer Institute's (PSI) project STARS (Steady-state and Transient Analysis Research for the Swiss reactors). In particular, the codes chosen for the coupling, i.e. the CFD code ANSYS CFX V11.0 and the system code US-NRC TRACE V5.0, are part of the STARS codes system. Their main features are also described in Chap. 2. The development of the coupled tool, named CFX/TRACE from the names of the two constitutive codes, has proven to be a complex and broad-based task, and therefore constraints had to be put on the target requirements, while keeping in mind a certain modularity to allow future extensions to be made with minimal efforts. After careful consideration, the coupling was defined to be on-line, parallel and with non-overlapping domains connected by an interface, which was developed through the Parallel Virtual Machines (PVM) software, as described in Chap. 3. Moreover, two numerical coupling schemes were implemented and tested: a sequential explicit scheme and a sequential semi-implicit scheme. Finally, it was decided that the coupling would be single

  11. Reactivity of main components and substituent distribution in esterified sugarcane bagasse prepared by effective solid phase reaction.

    Gan, Tao; Zhang, Yanjuan; Chen, Yane; Hu, Huayu; Yang, Mei; Huang, Zuqiang; Chen, Dong; Huang, Aimin

    2018-02-01

    Three main components of lignocellulose (cellulose, hemicellulose, and lignin isolated from sugarcane bagasse (SCB)) as well as holocellulose and SCB were modified with maleic acid by mechanical activation (MA)-assisted solid phase reaction (MASPR) technology. The order of reactivity was found to be lignin>hemicellulose>cellulose. The amorphous structure of lignin and hemicellulose mainly attributed to their better reactivity, and the modified lignin could reach a maximum degree of esterification (DE) of 93.45%. MA improved the accessibility and reactivity of cellulose, as the DE of modified cellulose gradually increased with milling time and reached the maximum value of 57.30% at 120min, which had significant effect on structure changes and DE of modified holocellulose and SCB. MA enhanced the esterification of all three components in lignocellulose with relatively high substituent distribution in them, and maleated SCB with a maximum DE of 64.17% was successfully prepared by this simple, green, and effective MASPR technology. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Effect of oral contraceptives and/or metformin on GLP-1 secretion and reactive hypoglycemia in PCOS

    Glintborg, Dorte; Mumm, Hanne; Holst, Jens Juul

    2017-01-01

    CONTEXT: Insulin resistance in polycystic ovary syndrome (PCOS) may increase the risk of reactive hypoglycaemia (RH) and decrease glucagon-like peptide-1 (GLP-1) secretion. The possible effects of treatment with oral contraceptives (OCP) and/or metformin on GLP-1 secretion and risk of RH in PCOS ...... significantly lower in obese vs. lean patients and were inversely associated with BMI. CONCLUSIONS: AUC GLP-1 levels were unchanged during treatment. Increased risk of hypoglycemia during metformin +OCP could be associated with increased insulin secretion.......CONTEXT: Insulin resistance in polycystic ovary syndrome (PCOS) may increase the risk of reactive hypoglycaemia (RH) and decrease glucagon-like peptide-1 (GLP-1) secretion. The possible effects of treatment with oral contraceptives (OCP) and/or metformin on GLP-1 secretion and risk of RH in PCOS......, glucose, insulin, and C-peptide during 5 h OGTT. RESULTS: Fasting GLP-1 levels increased during metformin+OCP vs. OCP treatment, whereas AUC GLP-1 levels were unchanged during medical treatment. The prevalence of reactive hypoglycemia increased from 9/65 to 14/65 after intervention (P

  13. Reactive arthritis induced by bacterial vaginosis: Prevention with an effective treatment

    Zohreh Aminzadeh

    2013-01-01

    Full Text Available We report a 42-year-old woman with reactive arthritis induced by bacterial vaginosis who presented with oligoarthritis with an additive form, arthralgia, and enthesitis. She hasn′t had a history of diarrhea or dysuria or vaginal secretion, or sexually transmitted infections (STIs. The laboratory tests were normal except for a high erythrocyte sedimentation rate (ESR. Her pelvic examination revealed homogeneous white grey and malodorous vaginal discharge on the vaginal wall and Pap smear and Gram-stained smear of vaginal swab was consistent with bacterial vaginosis. She responded to metronidazole therapy and her six-month follow up hasn′t shown recurrence of arthritis. As reactive arthritis (ReA is a paradigm of a rheumatic disease in which the initiating infectious cause is known, so early use of antimicrobial drugs may prevent the development of musculoskeletal symptoms which are triggered by infections.

  14. Reactivity effect of a heavy water tank as reflector in the IPEN/MB-01 reactor

    Santos, Adimir dos; Fuga, Rinaldo

    2013-01-01

    This experiment comprises a set of experiments performed in the IPEN/MB-01 reactor and described in the International Handbook of Evaluated Reactor Physics Benchmark Experiments, specifically the experiment aim to evaluate the reactivity due to the heavy water tank placed at reflector region of the IPEN/MB-01 reactor. An aluminum tank was designed to be filled with heavy water and positioned at the west face of the IPEN/MB-01, additionally the experiment was also designed to allow variable heavy water height inside of this tank providing different neutron leakage rate in the west face of the IPEN/MB-01, consequently providing a series of interesting combinations. The measured quantities in the experiment are reactivities and critical control bank positions for several combinations of the control banks and an excess of reactivity of the heavy water tank. The experiment will be simulated using a Monte Carlo code MCNP in order to compare the different critical control bank position. (author)

  15. Effect of reactive monomer on PS-b-P2VP film.

    Kim, H J; Shin, D M

    2014-08-01

    Poly(styrene-b-2-vinyl pyridine) (PS-b-P2VP) lamellar film which is hydrophobic block-hydrophilic polyelectrolyte block polymer of 52 kg/mol-b-57 kg/mol and PS-b-P2VP film with reactive monomer (RM257) were prepared for photonic gel films. The lamellar stacks, which is alternating layer of hydrophilic and hydrophobic moiety of PS-b-P2VP, were obtained by exposing the spin coated film under chloroform vapor. The lamellar films were quaternized with 5 wt% of iodomethane diluted by n-hexane. We reported about the influence of reactive monomer on those photonic gel films. Added reactive monomer photonic gel film had higher absorbance than pure photonic gel films. As a result the photonic gel film with RM had more clear color. The lamellar films were swollen by DI water, ethanol (aq) and calcium carbonate solution. The band gaps of the lamellar films were drastically shifted to longer wavelength swollen by calcium carbonate solution. And the lamellar films were shifted to shorter wave length swollen by ethanol. So each lamellar film showed different color.

  16. Differential effects of allergen challenge on large and small airway reactivity in mice.

    Chantal Donovan

    Full Text Available The relative contributions of large and small airways to hyperresponsiveness in asthma have yet to be fully assessed. This study used a mouse model of chronic allergic airways disease to induce inflammation and remodelling and determine whether in vivo hyperresponsiveness to methacholine is consistent with in vitro reactivity of trachea and small airways. Balb/C mice were sensitised (days 0, 14 and challenged (3 times/week, 6 weeks with ovalbumin. Airway reactivity was compared with saline-challenged controls in vivo assessing whole lung resistance, and in vitro measuring the force of tracheal contraction and the magnitude/rate of small airway narrowing within lung slices. Increased airway inflammation, epithelial remodelling and fibrosis were evident following allergen challenge. In vivo hyperresponsiveness to methacholine was maintained in isolated trachea. In contrast, methacholine induced slower narrowing, with reduced potency in small airways compared to controls. In vitro incubation with IL-1/TNFα did not alter reactivity. The hyporesponsiveness to methacholine in small airways within lung slices following chronic ovalbumin challenge was unexpected, given hyperresponsiveness to the same agonist both in vivo and in vitro in tracheal preparations. This finding may reflect the altered interactions of small airways with surrounding parenchymal tissue after allergen challenge to oppose airway narrowing and closure.

  17. Reactive Arthritis

    Eren Erken

    2013-06-01

    Full Text Available Reactive arthritis is an acute, sterile, non-suppurative and inflammatory arthropaty which has occured as a result of an infectious processes, mostly after gastrointestinal and genitourinary tract infections. Reiter syndrome is a frequent type of reactive arthritis. Both reactive arthritis and Reiter syndrome belong to the group of seronegative spondyloarthropathies, associated with HLA-B27 positivity and characterized by ongoing inflammation after an infectious episode. The classical triad of Reiter syndrome is defined as arthritis, conjuctivitis and urethritis and is seen only in one third of patients with Reiter syndrome. Recently, seronegative asymmetric arthritis and typical extraarticular involvement are thought to be adequate for the diagnosis. However, there is no established criteria for the diagnosis of reactive arthritis and the number of randomized and controlled studies about the therapy is not enough. [Archives Medical Review Journal 2013; 22(3.000: 283-299

  18. Age-dependent effects of acute methylphenidate on amygdala reactivity in stimulant treatment-naive patients with Attention Deficit/Hyperactivity Disorder.

    Bottelier, Marco A; Schrantee, Anouk; Ferguson, Bart; Tamminga, Hyke G H; Bouziane, Cheima; Kooij, J J Sandra; de Ruiter, Michiel B; Reneman, Liesbeth

    2017-11-30

    In the present study, we investigate whether methylphenidate (MPH) affects emotional processing and whether this effect is modulated by age. We measured amygdala reactivity with functional Magnetic Resonance Imaging (fMRI) during processing of angry and fearful facial expressions in male stimulant treatment-naive patients with ADHD (N = 35 boys; N = 46 men) and 23 healthy control subjects (N = 11 boys; N = 12 men). In ADHD patients, we also measured amygdala reactivity 90min after an acute oral challenge with MPH (0.5mg/kg). Mean amygdala reactivity was analyzed for all subjects using a repeated measures analysis of variance (ANOVA). Whole-brain maps were analyzed for the patients only. At baseline, we found a age*diagnosis effect approaching significance (p = 0.05) in the right amygdala due to lower reactivity in children with Attention Deficit/Hyperactivity Disorder (ADHD) vs. controls (-31%), but higher reactivity in adults with ADHD vs. controls (+31%). MPH significantly reduced right amygdala reactivity in all patients, resulting in further reductions in children. In the left amygdala, reduction of amygdala reactivity was confined to adult ADHD patients whereas there was no change in children with ADHD. MPH-induced decrease of amygdala reactivity in adults might be a promising avenue for managing emotional dysregulation when replicated for chronic MPH treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. The reactive element effect of yttrium and yttrium silicon on high temperature oxidation of NiCrAl coating

    Ramandhany, S.; Sugiarti, E.; Desiati, R. D.; Martides, E.; Junianto, E.; Prawara, B.; Sukarto, A.; Tjahjono, A.

    2018-03-01

    The microstructure formed on the bond coat affects the oxidation resistance, particularly the formation of a protective oxide layer. The adhesion of bond coat and TGO increased significantly by addition of reactive element. In the present work, the effect of yttrium and yttrium silicon as reactive element (RE) on NiCrAl coating was investigated. The NiCrAl (without RE) and NiCrAlX (X:Y or YSi) bond coating were deposited on Hastelloy C-276 substrate by High Velocity Oxygen Fuel (HVOF) method. Isothermal oxidation was carried out at 1000 °C for 100 hours. The results showed that the addition of RE could prevent the breakaway oxidation. Therefore, the coating with reactive element were more protective against high temperature oxidation. Furthermore, the oxidation rate of NiCrAlY coating was lower than NiCrAlYSi coating with the total mass change was ±2.394 mg/cm2 after 100 hours of oxidation. The thickness of oxide scale was approximately 1.18 μm consisting of duplex oxide scale of spinel NiCr2O4 in outer scale and protective α-Al2O3 in inner scale.

  20. Potential side effects of unhealthy lifestyle choices and health risks on basal and reactive heart rate variability in college drinkers.

    Udo, Tomoko; Mun, Eun-Young; Buckman, Jennifer F; Vaschillo, Evgeny G; Vaschillo, Bronya; Bates, Marsha E

    2013-09-01

    Emerging adults often begin making independent lifestyle choices during college, yet the association of these choices with fundamental indicators of health and adaptability is unclear. The present study examined the relationship between health risks and neurocardiac function in college drinkers. Heart rate variability (HRV) was assessed at baseline and in reaction to a paced breathing challenge in 212 college drinkers (53.8% women). Basal HRV served as a general indicator of health. Reactive HRV (during paced breathing) was used as a marker of an individual's adaptability to challenge. The relationship of HRV to alcohol use, cigarette use, exercise, sleep, and body mass index (BMI) was assessed. Greater alcohol use and less exercise were associated with lower basal HRV. BMI was unrelated to basal HRV but was negatively associated with reactive HRV during the breathing challenge. High levels of alcohol use and lack of exercise are negative correlates of cardiovascular and general health, even in apparently healthy college drinkers. The negative relationship between BMI and reactive HRV suggests that overweight individuals have reduced ability to psychophysiologically adapt to challenges; understanding the temporal course of this relationship is needed. This study highlights the importance of examining HRV at baseline and in response to a challenge to capture the active neurocardiac processes that contribute to health and adaptive responding. The suppressive effects of health risks on HRV are modifiable; thus, HRV may be useful in evaluating the health benefits of lifestyle change and in promoting change behaviors in college drinkers.

  1. A Numerical Study on the Effects of Street‒canyon Aspect‒ratio on Reactive Pollutant Dispersion

    Park, S. J.; Kim, J.

    2014-12-01

    In this study, the effects of street‒canyon aspect‒ratio on reactive pollutant dispersion were investigated using the coupled CFD‒chemistry model. For this, flow characteristics were analyzed first in street canyons with different aspect ratios and flow regimes were classified according to the building height. For each flow regime, dispersion characteristics were investigated in views of reactive pollutant concentration and VOCs‒NOX ratio. Finally, the relations between pollutant concentration and aspect ratio in urban street canyons were investigated. In the case of H/S = 1.0 (H is building height and S is street width), one clockwise‒rotating vortex appeared vertically and the reverse and outward flows were dominant near the street bottom. In the case of H/S = 2.0, two counter‒rotating vortices appeared vertically in the street canyon. The primary (secondary) vortex rotating clockwise (counterclockwise) was formed in upper (lower) layer. The flow patterns affected the reactive pollutant concentration in street canyons. As building height increased, mean concentration of NO decreased when one vortex was generated in street canyons and increased when two vortexes appeared in street canyons. O3 concentration showed almost contrasted tendency with those of NO because O3 was depleted by the NO titration.

  2. Effect of Casmo-5 cross-section data and doppler temperature definitions on LWR reactivity initiated accidents - 166

    Grandi, G.; Smith, K.; Xu, Z.; Rhodes, J.

    2010-01-01

    During LWR Reactivity Initiated Accidents (RIA), the accurate evaluation of the Doppler reactivity feedback depends on the Doppler coefficient computed by the lattice physics code (e.g. CASMO-5), and on the effective Doppler temperature computed by the transient code (e.g. SIMULATE-3K) using the non-uniform intra-pellet temperature profile. CASMO-5 has many new features compared with its predecessor. Among them, the replacement of the L-library (based primarily on ENDF/B IV data) by the latest available nuclear data (ENDF/B VII.0), and the Monte Carlo based resonance elastic scattering model to overcome deficiencies in NJOY modeling have a significant impact on the fuel temperature coefficient, and hence on LWR RIA. The Doppler temperature effect in thermal reactors is driven by the 238 U absorption. The different effective Doppler temperature definitions, available in the literature, try to capture the considerable self-shielding of the 238 U absorption that occurs in the pellet surface by defining an appropriate fuel temperature to compute cross-sections. In this work, we investigate the effect of the nuclear data generated by CASMO-5 on RIA, as well as the impact of different effective Doppler temperature definitions, including one proposed by the authors. It is concluded: 1) LWR RIA evaluated using CASMO-5 cross section data will be milder because the energy released is ∼10% smaller; 2) the prompt enthalpy rise is barely affected by the choice of the Doppler temperature definition; and 3) the peak fuel enthalpy is affected by the choice of the Doppler temperature definition, the under-prediction of the Doppler reactivity by the 'NEA' Doppler temperature results in a conservative estimate of the peak fuel enthalpy. (authors)

  3. FOXO3a reactivation mediates the synergistic cytotoxic effects of rapamycin and cisplatin in oral squamous cell carcinoma cells

    Fang Liang; Wang Huiming; Zhou Lin; Yu Da

    2011-01-01

    FOXO3a, a well-known transcriptional regulator, controls a wide spectrum of biological processes. The Phosphoinositide-3-kinase (PI3K)/Akt signaling pathway inactivates FOXO3a via phosphorylation-induced nuclear exclusion and degradation. A loss or gain of FOXO3a activity has been correlated with efficiency of chemotherapies in various cancers including oral squamous cell carcinoma (OSCC). Therefore, in the current study, we have investigated the FOXO3a activity modulating and antitumor effects of rapamycin and cisplatin in OSCC cells. Cisplatin inhibited proliferation and induced apoptosis in a dose-dependent way in OSCC Tca8113 cells. Rapamycin alone had no effect on cell proliferation and apoptosis. Rapamycin downregulated the expression of S-phase kinase associated protein-2 (Skp2) and increased the FOXO3a protein stability but induced the upregulation of feedback Akt activation-mediated FOXO3a phosphorylation. Cisplatin decreased the phosphorylation of FOXO3a via Akt inhibition. Rapamycin combined with cisplatin as its feedback Akt activation inhibitor revealed the most dramatic FOXO3a nuclear localization and reactivation with the prevention of its feedback loop and exposed significant synergistic effects of decreased cell proliferation and increased apoptosis in vitro and decreased tumor size in vivo. Furthermore, the downstream effects of FOXO3a reactivation were found to be accumulation of p27 and Bim. In conclusion, rapamycin/cisplatin combination therapy boosts synergistic antitumor effects through the significant FOXO3a reactivation in OSCC cells. These results may represent a novel mechanism by which rapamycin/cisplatin combination therapy proves to be a potent molecular-targeted strategy for OSCC.

  4. Increased Back-Bonding Explains Step-Edge Reactivity and Particle Size Effect for CO Activation on Ru Nanoparticles.

    Foppa, Lucas; Copéret, Christophe; Comas-Vives, Aleix

    2016-12-28

    Carbon monoxide is a ubiquitous molecule, a key feedstock and intermediate in chemical processes. Its adsorption and activation, typically carried out on metallic nanoparticles (NPs), are strongly dependent on the particle size. In particular, small NPs, which in principle contain more corner and step-edge atoms, are surprisingly less reactive than larger ones. Hereby, first-principles calculations on explicit Ru NP models (1-2 nm) show that both small and large NPs can present step-edge sites (e.g., B 5 and B 6 sites). However, such sites display strong particle-size-dependent reactivity because of very subtle differences in local chemical bonding. State-of-the-art crystal orbital Hamilton population analysis allows a detailed molecular orbital picture of adsorbed CO on step-edges, which can be classified as flat (η 1 coordination) and concave (η 2 coordination) sites. Our analysis shows that the CO π-metal d π hybrid band responsible for the electron back-donation is better represented by an oxygen lone pair on flat sites, whereas it is delocalized on both C and O atoms on concave sites, increasing the back-bonding on these sites compared to flat step-edges or low-index surface sites. The bonding analysis also rationalizes why CO cleavage is easier on step-edge sites of large NPs compared to small ones irrespective of the site geometry. The lower reactivity of small NPs is due to the smaller extent of the Ru-O interaction in the η 2 adsorption mode, which destabilizes the η 2 transition-state structure for CO direct cleavage. Our findings provide a molecular understanding of the reactivity of CO on NPs, which is consistent with the observed particle size effect.

  5. Effects on nano zero-valent iron reactivity of interactions between hardness, alkalinity, and natural organic matter in reverse osmosis concentrate

    Hwang, Yuhoon; Shin, Hang-Sik

    2013-01-01

    , the influence of hardness, alkalinity, and organic matter on NZVI reactivity was evaluated by the response surface method (RSM). Hardness (Ca2 ) had a positive effect on NZVI reactivity by accelerating iron corrosion. In contrast, alkalinity (bicarbonate; HCO3-) and organic matter (humic acid; HA) had negative...... effects on NZVI reactivity due to morphological change to carbonate green rust, and to competitive adsorption of HA, respectively. The validity of the statistical prediction model derived from RSM was confirmed by an additional confirmation experiment, and the experimental result was within the 95......% confidential interval. Therefore, it can be said that the RSM model produced results that were statistically significant....

  6. Caffeic acid and quercetin exert caspases-independent apoptotic effects on Leishmania major promastigotes, and reactivate the death of infected phagocytes derived from BALB/c mice

    Radia Belkhelfa-Slimani

    2017-04-01

    Conclusions: The leishmanicidal effect of caffeic acid and quercetin on promastigotes and amastigotes, as well as reactivation of infected phagocytes apoptosis, suggested a potential therapeutic role against cutaneous leishmaniasis.

  7. Oxime reactivators and their in vivo and in vitro effects on nicotinic receptors

    Soukup, O.; Krůšek, Jan; Kaniaková, Martina; Kumar, U. K.; Oz, M.; Jun, D.; Fusek, J.; Kuča, K.; Tobin, G.

    2011-01-01

    Roč. 60, č. 4 (2011), s. 679-686 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA202/09/0806; GA MŠk(CZ) LC554 Grant - others:GA ČR(CZ) GAP303/11/1907 Institutional research plan: CEZ:AV0Z50110509 Keywords : organophosphates * patch-clamp * nicotinic receptors * reactivator * isometric muscle contraction * TE671 cells Subject RIV: FR - Pharmacology ; Medidal Chemistry Impact factor: 1.555, year: 2011

  8. Effect of hydrogen on the diode properties of reactively sputtered amorphous silicon Schottky barrier structures

    Morel, D.L.; Moustakas, T.D.

    1981-01-01

    The diode properties of reactively sputtered hydrogenated amorphous silicon Schottky barrier structures (a-SiH/sub x/ /Pt) have been investigated. We find a systematic relation between the changes in the open circuit voltage, the barrier height, and the diode quality factor. These results are accounted for by assuming that hydrogen incorporation into the amorphous silicon network removes states from the top of the valence band and sharpens the valence-band tail. Interfacial oxide layers play a significant role in the low hydrogen content, and low band-gap regime

  9. Effects of Human C-Reactive Protein on Pathogenesis of Features of the Metabolic Syndrome

    Pravenec, Michal; Kajiya, T.; Zídek, Václav; Landa, Vladimír; Mlejnek, Petr; Šimáková, Miroslava; Šilhavý, Jan; Malínská, H.; Oliyarnyk, O.; Kazdová, L.; Fan, J.; Wang, J.; Kurtz, T. W.

    2011-01-01

    Roč. 57, č. 4 (2011), s. 731-737 ISSN 0194-911X R&D Projects: GA MZd(CZ) NS9759; GA MŠk(CZ) ME08006; GA MŠk(CZ) 1M0520; GA ČR(CZ) GAP301/10/0290; GA ČR GAP303/10/0505; GA AV ČR(CZ) IAA500110805 Grant - others:EC(XE) HEALTH-F4-2010-241504 Institutional research plan: CEZ:AV0Z50110509 Keywords : C-reactive protein * metabolic syndrome * transgenic rat Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 6.207, year: 2011

  10. Post-deposition annealing effects in RF reactive magnetron sputtered indium tin oxide thin films

    Martinez, M A; Herrero, J; Gutierrez, M T [Inst. de Energias Renovables (CIEMAT), Madrid (Spain)

    1992-05-01

    Indium tin oxide films have been grown by RF reactive magnetron sputtering. The influence of the deposition parameters on the properties of the films has been investigated and optimized, obtaining a value for the figure of merit of 6700 ({Omega} cm){sup -1}. As-grown indium tin oxide films were annealed in vacuum and O{sub 2} atmosphere. After these heat treatments the electro-optical properties were improved, with values for the resistivity of 1.9x10{sup -4} {Omega} cm and the figure of merit of 26700 ({Omega} cm){sup -1}. (orig.).

  11. Effect of nonlinear void reactivity on bifurcation characteristics of a lumped-parameter model of a BWR: A study relevant to RBMK

    Verma, Dinkar, E-mail: dinkar@iitk.ac.in [Nuclear Engineering and Technology Program, Indian Institute of Technology Kanpur, Kanpur 208 016 (India); Kalra, Manjeet Singh, E-mail: drmanjeet.singh@dituniversity.edu.in [DIT University, Dehradun 248 009 (India); Wahi, Pankaj, E-mail: wahi@iitk.ac.in [Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)

    2017-04-15

    Highlights: • A simplified model with nonlinear void reactivity feedback is studied. • Method of multiple scales for nonlinear analysis and oscillation characteristics. • Second order void reactivity dominates in determining system dynamics. • Opposing signs of linear and quadratic void reactivity enhances global safety. - Abstract: In the present work, the effect of nonlinear void reactivity on the dynamics of a simplified lumped-parameter model for a boiling water reactor (BWR) is investigated. A mathematical model of five differential equations comprising of neutronics and thermal-hydraulics encompassing the nonlinearities associated with both the reactivity feedbacks and the heat transfer process has been used. To this end, we have considered parameters relevant to RBMK for which the void reactivity is known to be nonlinear. A nonlinear analysis of the model exploiting the method of multiple time scales (MMTS) predicts the occurrence of the two types of Hopf bifurcation, namely subcritical and supercritical, leading to the evolution of limit cycles for a range of parameters. Numerical simulations have been performed to verify the analytical results obtained by MMTS. The study shows that the nonlinear reactivity has a significant influence on the system dynamics. A parametric study with varying nominal reactor power and operating conditions in coolant channel has also been performed which shows the effect of change in concerned parameter on the boundary between regions of sub- and super-critical Hopf bifurcations in the space constituted by the two coefficients of reactivities viz. the void and the Doppler coefficient of reactivities. In particular, we find that introduction of a negative quadratic term in the void reactivity feedback significantly increases the supercritical region and dominates in determining the system dynamics.

  12. The effect of actinide thin films on the electronic structure and reactivity of various elements

    Gouder, T.; Colmenares, C.

    1994-12-08

    This report summarizes the experimental work carried out at the Lawrence Livermore National Laboratory on the electronic structure and reactivity of uranium thin films on Pd, Pt, Si, graphite, Cu, and Au substrates from 1990 to 1993. The U-Pd system was studied in the most detail because it was the first to be chosen right after the completion of the experimental equipment. We first studied and characterized clean U overlayers and the possible surface reactions between this metal and the substrates studied. We then subjected these systems to reactive conditions such as heating and adsorbing corrosive gases (O{sub 2}, CO, CO{sub 2}, and C{sub 2}H{sub 4}). Finally we investigated the diffusion of U metal and some of its compounds into the substrates. A new technique was developed, based on Auger Electron Spectroscopy, to follow in real time the diffusion of U overlayers into the substrate. The temperature of the sample is ramped linearly up to 900{degrees}C while following the Auger peak intensities of the two components for a given system. Diffusion rates are obtained by differentiating the measured intensity curves, then peaks result corresponding to diffusion processes with different activation energies. This technique bears a strong similarity to thermal desorption spectroscopy (TDS), where the sample is heated linearly and the rate of desorption is measured as a function of temperature and heating rate.

  13. Cue reactivity towards bodies in anorexia nervosa - common and differential effects in adolescents and adults.

    Horndasch, S; Kratz, O; Van Doren, J; Graap, H; Kramer, R; Moll, G H; Heinrich, H

    2018-02-01

    Aberrant reward mechanisms with regard to slim body shapes are discussed in patients with anorexia nervosa (AN). The aim of the present study was to examine of cue reactivity toward body shapes in AN via the late positive potential (LPP), an event-related electroencephalography (EEG) component. By including adolescents and adults, aspects of development and chronification could be studied (2 × 2 design). Thirty-two female AN patients (19 adolescents and 13 adults) and 37 control participants (16 adolescents and 21 adults) were included. Standardized photographic stimuli showing women's bodies in underwear from five body mass index (BMI) categories (extremely underweight to extremely overweight) were presented. During picture evaluation, EEG activity was recorded (10-20 system). The LPP was measured in two time windows characterized by different topographies (450-700 ms: posterior; 1000-1300 ms: central). Regarding the posterior component, LPP amplitudes were clearly reduced in adult but not in adolescent patients; for both time windows the LPP showed differential patterns over BMI categories for patients and controls. Regarding the central component, a highly significant linear decrease from extremely underweight to extremely overweight body shapes was revealed in patients and no significant modulation in control participants. Adolescent and adult patients show increased sustained attention toward extremely underweight bodies. In chronically ill patients, this bias appears to be accompanied by generally reduced automatic attention. The LPP findings provide a differentiated picture of aberrant cue reactivity which could be interpreted as motivated attention toward body shapes in AN.

  14. Development of reactivity feedback effect measurement techniques under sub-critical condition in fast reactors

    Kitano, A.; Nishi, H.; Suzuki, T.; Okajima, S.; Kanemoto, S.

    2012-01-01

    The first-of-a-kind reactor has been licensed by a safety examination of the plant design based on the measured data in precedent mock-up experiments. The validity of the safety design can be confirmed without a mock-up experiment, if the reactor feed-back characteristics can be measured before operation, with the constructed reactor itself. The 'Synthesis Method', a systematic and sophisticated method of sub-criticality measurement, is proposed in this work to ensure the safety margin before operation. The 'Synthesis Method' is based on the modified source multiplication method (MSM) combined with the noise analysis method to measure the reference sub-criticality level for MSM. A numerical simulation for the control-rod reactivity worth and the isothermal feed-back reactivity was conducted for typical fast reactors of 100 MWe-size, 300 MWe-size, 750 MWe-size, and 1500 MWe-size to investigate the applicability of Synthesis Method. The number of neutron detectors and their positions necessary for the measurement were investigated for both methods of MSM and the noise analysis by a series of parametric survey calculations. As a result, it was suggested that a neutron detector located above the core center and three or more neutron detectors located above the radial blanket region enable the measurement of sub-criticality within 10% uncertainty from -$0.5 to -$2 and within 15% uncertainty for the deeper sub-criticality. (authors)

  15. Effect of charged impurities and morphology on oxidation reactivity of graphene

    Yamamoto, Mahito; Cullen, William; Einstein, Theodore; Fuhrer, Michael

    2012-02-01

    Chemical reactivity of single layer graphene supported on a substrate is observed to be enhanced over thicker graphene. Possible mechanisms for the enhancement are Fermi level fluctuations due to ionized impurities on the substrate, and structural deformation of graphene induced by coupling to the substrate geometry. Here, we study the substrate-dependent oxidation reactivity of graphene, employing various substrates such as SiO2, mica, SiO2 nanoparticle thin film, and hexagonal boron nitride, which exhibit different charged impurity concentrations and surface roughness. Graphene is prepared on each substrate via mechanical exfoliation and oxidized in Ar/O2 mixture at temperatures from 400-600 ^oC. After oxidation, the Raman spectrum of graphene is measured, and the Raman D to G peak ratio is used to quantify the density of point defects introduced by oxidation. We will discuss the correlations among the defect density in oxidized graphene, substrate charge inhomogeneity, substrate corrugations, and graphene layer thickness. This work has been supported by the University of Maryland NSF-MRSEC under Grant No. DMR 05-20471 with supplemental funding from NRI, and NSF-DMR 08-04976.

  16. The effects of zinc bath temperature on the coating growth behavior of reactive steel

    Wang Jianhua, E-mail: super_wang111@hotmail.com [School of Mechanical Engineering, Xiangtan University, Xiangtan, 411105 (China); Key Laboratory of Materials Design and Preparation Technology of Hunan Province, Xiangtan University, Xiangtan, 411105 (China); Tu Hao; Peng Bicao; Wang Xinming; Yin, Fucheng [School of Mechanical Engineering, Xiangtan University, Xiangtan, 411105 (China); Key Laboratory of Materials Design and Preparation Technology of Hunan Province, Xiangtan University, Xiangtan, 411105 (China); Su Xuping, E-mail: xuping@xtu.edu.cn [School of Mechanical Engineering, Xiangtan University, Xiangtan, 411105 (China); Key Laboratory of Materials Design and Preparation Technology of Hunan Province, Xiangtan University, Xiangtan, 411105 (China)

    2009-11-15

    The purpose of this work is to identify the influence of zinc bath temperature on the morphology and the thickness of reactive steel (Fe-0.1 wt.%Si alloy) coatings. The Fe-0.1 wt.%Si samples were galvanized for 3 min at temperatures in the range of 450-530 deg. C in steps of 10 deg. C. The coatings were characterized by using scanning electron microscopy/energy dispersive X-rays analysis. It was found that the coating thickness reaches the maximum at 470 deg. C and the minimum at 500 deg. C, respectively. When the reactive steel is galvanized at temperatures in the range of 450-490 deg. C, the coatings have a loose {zeta} layer on the top of a compact {delta} layer. With the increase of the galvanizing temperature, the {zeta} layer becomes looser. When the temperature is at 500 deg. C, the {zeta} phase disappears. With the increase of temperature, the coatings change to be a diffuse-{Delta} layer ({delta}+ liquid zinc).

  17. Water surface coverage effects on reactivity of plasma oxidized Ti films

    Pranevicius, L.; Pranevicius, L.L.; Vilkinis, P.; Baltaragis, S.; Gedvilas, K.

    2014-01-01

    Highlights: • The reactivity of Ti films immersed in water vapor plasma depends on the surface water coverage. • The adsorbed water monolayers are disintegrated into atomic constituents on the hydrophilic TiO 2 under plasma radiation. • The TiO 2 surface covered by water multilayer loses its ability to split adsorbed water molecules under plasma radiation. - Abstract: The behavior of the adsorbed water on the surface of thin sputter deposited Ti films maintained at room temperature was investigated in dependence on the thickness of the resulting adsorbed water layer, controllably injecting water vapor into plasma. The surface morphology and microstructure were used to characterize the surfaces of plasma treated titanium films. Presented experimental results showed that titanium films immersed in water vapor plasma at pressure of 10–100 Pa promoted the photocatalytic activity of overall water splitting. The surfaces of plasma oxidized titanium covered by an adsorbed hydroxyl-rich island structure water layer and activated by plasma radiation became highly chemically reactive. As water vapor pressure increased up to 300–500 Pa, the formed water multilayer diminished the water oxidation and, consequently, water splitting efficiency decreased. Analysis of the experimental results gave important insights into the role an adsorbed water layer on surface of titanium exposed to water vapor plasma on its chemical activity and plasma activated electrochemical processes, and elucidated the surface reactions that could lead to the split of water molecules

  18. Effects of variable sticking coefficients on the stability of reactive sputtering process

    Li Chuan; Hsieh Janghsing

    2004-01-01

    In reactive sputtering, the introduction of a reactive gas can lead to a hysteresis transition from metal to compounds in both the target and substrate. The hysteresis transition is characterized by a sudden change in partial pressure, sputtering rate, fraction of compound formation, etc. Therefore, stability is an important issue in the process control. In this paper, a mathematical model with variable sticking coefficients based on surface kinetics is used to study the stability of the process. The variable sticking coefficient represents different mechanisms for surface reactions from the Langmuir to precursor type. In order to facilitate the analysis, several nondimensional parameters are identified and used for formulation. Results show that an unsteady system converges to a steady state relatively fast at low inflow rates. With an eigenvalue analysis, the range of positive eigenvalues is consistent with the presence of a hysteresis loop. It is also found that when the chemical reaction on the substrate is moderate, a higher sputter yield of the compound leads to a more stable steady state at lower inflow rates. Regarding the sticking mechanism, for the type of precursors with the parameter k < 1, the compound is easier to form and saturate on the surface due to the higher default sticking coefficient and the lower operating conditions for the hysteresis transition

  19. The multitasking framework: the effects of increasing workload on acute psychobiological stress reactivity.

    Wetherell, Mark A; Carter, Kirsty

    2014-04-01

    A variety of techniques exist for eliciting acute psychological stress in the laboratory; however, they vary in terms of their ease of use, reliability to elicit consistent responses and the extent to which they represent the stressors encountered in everyday life. There is, therefore, a need to develop simple laboratory techniques that reliably elicit psychobiological stress reactivity that are representative of the types of stressors encountered in everyday life. The multitasking framework is a performance-based, cognitively demanding stressor, representative of environments where individuals are required to attend and respond to several different stimuli simultaneously with varying levels of workload. Psychological (mood and perceived workload) and physiological (heart rate and blood pressure) stress reactivity was observed in response to a 15-min period of multitasking at different levels of workload intensity in a sample of 20 healthy participants. Multitasking stress elicited increases in heart rate and blood pressure, and increased workload intensity elicited dose-response increases in levels of perceived workload and mood. As individuals rarely attend to single tasks in real life, the multitasking framework provides an alternative technique for modelling acute stress and workload in the laboratory. Copyright © 2013 John Wiley & Sons, Ltd.

  20. Effects of solvent and structure on the reactivity of 6-substituted nicotinic acids with diazodiphenylmethane in aprotic solvents

    BRATISLAV Ž. JOVANOVIĆ

    2009-12-01

    Full Text Available The rate constants for the reactions of diazodiphenylmethane (DDM with 6-substituted nicotinic acids in aprotic solvents at 30 °C were determined. The obtained second order rate constants in aprotic solvents, together with literature data for benzoic and nicotinic acids in protic solvents, were used for the calculation of solvent effects, employing the Kamlet-Taft solvatochromic equation (linear solvation energy relationship – LSER in the form: log k = log k0 + s* + a + b. The correlations of the kinetic data were performed by means of multiple linear regression analysis taking appropriate solvent parameters. The sign of the equation coefficients (s, a and b were in agreement with the postulated reaction mechanism, and the mode of the solvent influences on the reaction rate is discussed based on the correlation results. A similar contribution of the non-specific solvent effect and electrophilic solvation was observed for all acids, while the highest contribution of nucleophilic solvation was influenced by their high acidity. Correlation analysis of the rate data with substituent p parameters in an appropriate solvent using the Hammett equation was also performed. The substituent effect on the acid reactivity was higher in aprotic solvents of higher dipolarity/polarizability. The mode of the transmission of the substituent effect is discussed in light of the contribution of solute–solvent interaction on the acid reactivity.

  1. Hall effects on unsteady MHD reactive flow of second grade fluid through porous medium in a rotating parallel plate channel

    Krishna, M. Veera; Swarnalathamma, B. V.

    2017-07-01

    We considered the transient MHD flow of a reactive second grade fluid through porous medium between two infinitely long horizontal parallel plates when one of the plate is set into uniform accelerated motion in the presence of a uniform transverse magnetic field under Arrhenius reaction rate. The governing equations are solved by Laplace transform technique. The effects of the pertinent parameters on the velocity, temperature are discussed in detail. The shear stress and Nusselt number at the plates are also obtained analytically and computationally discussed with reference to governing parameters.

  2. Mild effects of gestational stress and social reactivity on the onset of mother-young interactions and bonding in sheep.

    Coulon, Marjorie; Lévy, Frédéric; Ravel, Christine; Nowak, Raymond; Boissy, Alain

    2014-12-01

    Consequences of prenatal stress on mother-young relationships are well-documented in altricial mammals but less so in precocial mammals. In this study, we investigated the effects of unpredictable aversive events on maternal behavior and mutual mother-young recognition in pregnant ewes while accounting for modulatory effects of ewe reactivity. From a population of 120 Romane-breed ewes, we selected 20 high-responsive (HR) and 20 low-responsive (LR) ewes according to pre-mating reactivity assessed in isolation tests. Over the final third of pregnancy, 10 HR ewes and 10 LR ewes were exposed daily to various aversive events such as social isolation, mixing and transport (stressed ewes), while the other 20 ewes were not exposed to aversive events (control ewes). Although the treatment induced chronic stress, physiologically confirmed by an increase in salivary cortisol following transport and sham shearing, maternal behavior of stressed ewes observed during the first 30 min postpartum and in the selectivity test 1 h 30 min later did not differ from controls. However, in a maternal motivation test performed 48 h postpartum, stressed ewes vocalized less than controls when separated from their lambs, and walked less readily past an unknown object to reach their lambs. Lambs of stressed ewes spent more time near their dam in a preference test performed 15 h after birth compared to control-ewe lambs. HR ewes spent more time grooming their lambs than LR ewes. We posit that domestication could have selected animals displaying robust expression of maternal behavior related to social reactivity and producing offspring that are better adapted to challenging situations.

  3. Acute effects of muscle fatigue on anticipatory and reactive postural control in older individuals: a systematic review of the evidence.

    Papa, Evan V; Garg, Hina; Dibble, Leland E

    2015-01-01

    Falls are the leading cause of traumatic brain injury and fractures and the No. 1 cause of emergency department visits by older adults. Although declines in muscle strength and sensory function contribute to increased falls in older adults, skeletal muscle fatigue is often overlooked as an additional contributor to fall risk. In an effort to increase awareness of the detrimental effects of skeletal muscle fatigue on postural control, we sought to systematically review research studies examining this issue. The specific purpose of this review was to provide a detailed assessment of how anticipatory and reactive postural control tasks are influenced by acute muscle fatigue in healthy older individuals. An extensive search was performed using the CINAHL, Scopus, PubMed, SPORTDiscus, and AgeLine databases for the period from inception of each database to June 2013. This systematic review used standardized search criteria and quality assessments via the American Academy for Cerebral Palsy and Developmental Medicine Methodology to Develop Systematic Reviews of Treatment Interventions (2008 version, revision 1.2, AACPDM, Milwaukee, Wisconsin). A total of 334 citations were found. Six studies were selected for inclusion, whereas 328 studies were excluded from the analytical review. The majority of articles (5 of 6) utilized reactive postural control paradigms. All studies incorporated extrinsic measures of muscle fatigue, such as declines in maximal voluntary contraction or available active range of motion. The most common biomechanical postural control task outcomes were spatial measures, temporal measures, and end-points of lower extremity joint kinetics. On the basis of systematic review of relevant literature, it appears that muscle fatigue induces clear deteriorations in reactive postural control. A paucity of high-quality studies examining anticipatory postural control supports the need for further research in this area. These results should serve to heighten

  4. Photodegradation of Reactive Golden Yellow R Dye Catalyzed by Effective Titania (TiO2)

    Bedurus, E.A.; Marinah Mohd Ariffin; Mohd Hasmizam Razali

    2015-01-01

    In the present research, Microwave Assisted Synthesis (MAS) method was applied to synthesize titania (TiO 2 ) at 150 degree Celsius in a range of 2-6 hours heating time. Each prepared TiO 2 were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and nitrogen gas (N 2 ) sorption analysis (Brunaeur-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) calculation) techniques. The TiO 2 prepared by MAS 150 degree Celsius (4 hours) has emerged with the highest photo catalytic activity. Within 4 hours, the TiO 2 managed to catalyze the degradation of Reactive Golden Yellow R dye up to 98.51 %. This is because of the TiO 2 possessed high crystallinity of anatase phase, small crystallite size and high pore volume compared to other prepared TiO 2 . (author)

  5. Effects of glucose on the Reactive Black 5 (RB5 decolorization by two white rot basidiomycetes

    Tony Hadibarata

    2011-11-01

    Full Text Available The capacities of glucose in the decolorization process of an azo dye, Reactive Black 5 (RB5, by two white rot basidiomycetes, Pleurotus sp. F019 and Trametes sp. F054 were investigated. The results indicated that the dye degradation by the two fungi was extremely correlated with the presence of glucose in the culture and the process of fungi growth. Decolorization of 200 mg dye/l was increased from 62% and 69% to 100% within 20–25 h with the increase of glucose from 5 to 15 g/l, and the activity of manganese dependent peroxidase (MnP increased by 2–9 fold in this case. Hydrogen peroxide of 0.55 mg/l and 0.43 mg/l were detected in 10 h in Pleurotus sp. F019 and Trametes sp. F054 cultures.

  6. Effects of water content on reactive transport of Sr in Chernobyl sand columns

    Szenknect, S.; Dewiere, L.; Ardois, C.; Gaudet, J.P.

    2005-01-01

    Full text of publication follows: While transport of non-reactive solutes has been studied extensively in unsaturated porous media, much less is known about the factors that control the transport of sorbing solutes in unsaturated conditions. Three laboratory techniques were used to analyze the transport of Sr in the aeolian sand from Chernobyl Pilot Site [1] in both saturated and unsaturated flow conditions. Batch experiments were performed to study the chemical equilibrium state of the soil/solution system. Stirred flow-through reactor (SFTR) experiments were performed to study the kinetics and reversibility of sorption reactions at the surface of solid particles. Column experiments were also performed in saturated and unsaturated steady flow conditions. Experimental data pointed out a non-linear, instantaneous and reversible sorption process of Sr. A suitable cation-exchange model was used to describe the solute/soil reaction. The former model was coupled with transport models to describe behavior of Sr in saturated [2] and unsaturated flow conditions. Transport properties of sand packed columns have been determined with an inert tracer (HTO). BTCs obtained under saturated conditions exhibit a small amount of dispersion compared to those obtained under unsaturated conditions. Classical advection-dispersion model described successfully saturated tritium breakthrough curves (BTCs), whereas a mobile-immobile model (MIM) was required to described asymmetrical unsaturated BTCs. The MIM assumes that the porous medium contains a mobile water phase in which convective-dispersive transport occurs, and a immobile water phase with which solutes can exchange with a first order kinetic. In our experiments, transport by advection in the mobile phase is the predominant process whatever the flow conditions and mass transfer rate between the mobile and immobile regions is the predominant process for broadening the BTCs. Since dispersion is blurred by mass transfer resistance, the

  7. Effect of reactive agent and transesterification catalyst on properties of PLA/PBAT blends

    Pitivut, S; Suttiruengwong, S; Seadan, M

    2015-01-01

    This research aimed to study the properties of poly (lactic acid) (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) blends with two different reactive systems: free radical reaction through peroxide (Perkadox) and transesterification catalyst (tetrabutyl titanate; TBT). Two blends composed of PLA as a matrix phase with the composition of 80 and 70 percent by weight. PLA/PBAT blends with Perkadox were prepared in twin screw extruder, whereas PLA/PBAT blends with TBT were prepared in an internal mixer. The morphology of the blends was investigated by scanning electron microscope (SEM). Tensile and impact testingsof the blends were reported. In case of the blends with Perkadox, SEM micrographs revealed that the size of particles was substantially reduced when adding more Perkadox. Young's modulus and the tensile strength of all blend ratios were insignificantly changed, whereas the elongation at break was decreased when compared to non-reactive blends due to the possible crosslinking reaction as observed from melt flow index (MFI) values. When adding Perkadox, the impact strength of PLA/PBAT (80/20) remained almost unchanged. However, the impact strength of PLA/PBAT (70/30) was enhanced, increasing to 110% for 0.05 phr Perkadox. In case of the blends with TBT, SEM micrographs showed the decrease in the particle size of PBAT phase when adding TBT. Young's modulus and the tensile strength of all blend ratios were not different, but the elongation at break was improved when adding TBT owing to the transesterification reaction. For PLA/PBAT (80/20), the elongation at break was increased by 39%, whereas the elongation at break was increased by 15% for PLA/PLA (70/30). The impact strength of all blend ratios unaffected. (paper)

  8. On the export of reactive nitrogen from Asia: NOx partitioning and effects on ozone

    T. H. Bertram

    2013-05-01

    Full Text Available The partitioning of reactive nitrogen (NOy was measured over the remote North Pacific during spring 2006. Aircraft observations of NO, NO2, total peroxy nitrates (ΣPNs, total alkyl and multi-functional nitrates (ΣANs and nitric acid (HNO3, made between 25° and 55° N, confirm a controlling role for peroxyacyl nitrates in NOx production in aged Asian outflow. ΣPNs account for more than 60% of NOy above 5 km, while thermal dissociation limits their contribution to less than 10% in the lower troposphere. Using simultaneous observations of NOx, ΣPNs, ΣANs, HNO3 and average wind speed, we calculate the flux of reactive nitrogen through the meridional plane of 150° W (between 20° and 55° N to be 0.007 ± 0.002 Tg N day−1, which provides an upper limit of 23 ± 6.5% on the transport efficiency of NOy from East Asia. Observations of NOx, and HOx are used to constrain a 0-D photochemical box model for the calculation of net photochemical ozone production or tendency (Δ O3 as a function of aircraft altitude and NOx concentrations. The model analysis indicates that the photochemical environment of the lower troposphere (altitude 3 destruction, with an experimentally determined crossover point between net O3 destruction and net O3 production of 60 pptv NOx. Qualitative indicators of integrated net O3 production derived from simultaneous measurements of O3 and light alkanes (Parrish et al., 1992, also indicate that the north Pacific is, on average, a region of net O3 destruction.

  9. Electron beam processing of rubber wood fibers - polypropylene composites. Effects of reactive additives on the physical and mechanical properties

    Nor Yuziah Mohd Yunus; Jalaluddin Harun; Khairul Zaman

    2000-01-01

    The purpose of this study is to determine the suitability of producing agro-fiber reinforced plastic composite (agro-FRPC) from rubber wood fiber blended in polypropylene matrix. The effects of varying fiber dimension and fiber content on the physical and mechanical properties of the composite were evaluated to provide an insight into the fiber matrix adhesion. The effects of reactive additives on the physical and mechanical properties of the composite were evaluated which provides the insight on the reinforcement of the composite. Rubber wood fiber used in this study is currently being used in the manufacturing of medium density fiber (MDF) board. Two sizes of rubber wood fiber were used i.e. 0.5-1.0 mm and 1.0-2.0 mm. Homopolymer polypropylene of MFI 14.0 was used as a matrix. The irradiation work was carried out using electron beam accelerator, 3.0 MeV, 3.0 mA. Various types of reactive additives (RA) with mono-functional, di-functional, tri-functional and oligomer were applied in the blend. For comparison, a conventional chemical cross-linking using two types of maleated polypropylene, MPA (Mw=9,000) and PMAP (Mw=220,000) were also performed. (author)

  10. Electron beam processing of rubber wood fibers - polypropylene composites. Effects of reactive additives on the physical and mechanical properties

    Nor Yuziah Mohd Yunus; Jalaluddin Harun [Universiti Putra Malaysia, Selangor Darul Ehsan (Malaysia); Khairul Zaman [Malaysian Institute for Nuclear Technology Research (MINT), Selangor Darul Ehsan (Malaysia)

    2000-07-01

    The purpose of this study is to determine the suitability of producing agro-fiber reinforced plastic composite (agro-FRPC) from rubber wood fiber blended in polypropylene matrix. The effects of varying fiber dimension and fiber content on the physical and mechanical properties of the composite were evaluated to provide an insight into the fiber matrix adhesion. The effects of reactive additives on the physical and mechanical properties of the composite were evaluated which provides the insight on the reinforcement of the composite. Rubber wood fiber used in this study is currently being used in the manufacturing of medium density fiber (MDF) board. Two sizes of rubber wood fiber were used i.e. 0.5-1.0 mm and 1.0-2.0 mm. Homopolymer polypropylene of MFI 14.0 was used as a matrix. The irradiation work was carried out using electron beam accelerator, 3.0 MeV, 3.0 mA. Various types of reactive additives (RA) with mono-functional, di-functional, tri-functional and oligomer were applied in the blend. For comparison, a conventional chemical cross-linking using two types of maleated polypropylene, MPA (Mw=9,000) and PMAP (Mw=220,000) were also performed. (author)

  11. The Effects of Allicin, a Reactive Sulfur Species from Garlic, on a Selection of Mammalian Cell Lines

    Martin C. H. Gruhlke

    2016-12-01

    Full Text Available Garlic (Allium sativum L. has been used as a spice and medicinal plant since ancient times. Garlic produces the thiol-reactive defence substance, allicin, upon wounding. The effects of allicin on human lung epithelium carcinoma (A549, mouse fibroblast (3T3, human umbilical vein endothelial cell (HUVEC, human colon carcinoma (HT29 and human breast cancer (MCF7 cell lines were tested. To estimate toxic effects of allicin, we used a standard MTT-test (methylthiazoltetrazolium for cell viability and 3H-thymidine incorporation for cell proliferation. The glutathione pool was measured using monobromobimane and the formation of reactive species was identified using 2′,7′-dichlorofluoresceine-diacetate. The YO-PRO-1 iodide staining procedure was used to estimate apoptosis. Allicin reduced cell viability and cell proliferation in a concentration dependent manner. In the bimane test, it was observed that cells treated with allicin showed reduced fluorescence, suggesting glutathione oxidation. The cell lines tested differed in sensitivity to allicin in regard to viability, cell proliferation and glutathione oxidation. The 3T3 and MCF-7 cells showed a higher proportion of apoptosis compared to the other cell types. These data show that mammalian cell lines differ in their sensitivity and responses to allicin.

  12. Effect of oral contraceptives and/or metformin on GLP-1 secretion and reactive hypoglycaemia in polycystic ovary syndrome

    Dorte Glintborg

    2017-06-01

    Full Text Available Context: Insulin resistance in polycystic ovary syndrome (PCOS may increase the risk of reactive hypoglycaemia (RH and decrease glucagon-like peptide-1 (GLP-1 secretion. The possible effects of treatment with oral contraceptives (OCP and/or metformin on GLP-1 secretion and risk of RH in PCOS is undetermined. Setting: Outpatient clinic. Patients and interventions: Randomized, controlled clinical trial. Ninety women with PCOS were randomized to 12-month treatment with OCP (150 mg desogestrel + 30 mg ethinylestradiol, metformin (2 g/day or metformin + OCP. Five-hour oral glucose tolerance tests (5-h OGTT measuring fasting and area under the curve (AUC for GLP-1, glucose, insulin and C-peptide were performed before and after the intervention period. Sixty-five women completed the study and 34 weight-matched healthy women were included as controls. Main outcome measures: Changes in GLP-1, glucose, insulin and C-peptide during 5-h OGTT. Results: Fasting GLP-1 levels increased during metformin + OCP vs OCP treatment, whereas AUC GLP-1 levels were unchanged during medical treatment. The prevalence of reactive hypoglycemia increased from 9/65 to 14/65 after intervention (P < 0.01 and was more common after treatment with metformin + OCP (increase from 3/23 to 6/23, P = 0.01. Reactive hypoglycaemia was associated with higher insulin and C-peptide levels during 5-h OGTT, but was unassociated with BMI and AUC GLP-1. GLP-1 levels were comparable in PCOS vs controls. AUC GLP-1 levels were significantly lower in obese vs lean patients and were inversely associated with BMI. Conclusions: AUC GLP-1 levels were unchanged during treatment. Increased risk of hypoglycemia during metformin + OCP could be associated with increased insulin secretion.

  13. Effect of charge state and stoichiometry on the structure and reactivity of nickel oxide clusters with CO

    Johnson, Grant E.; Reilly, Nelly M.; Castleman, A. W., Jr.

    2009-02-01

    The collision induced fragmentation and reactivity of cationic and anionic nickel oxide clusters with carbon monoxide were studied experimentally using guided-ion-beam mass spectrometry. Anionic clusters with a stoichiometry containing one more oxygen atom than nickel atom (NiO2-, Ni2O3-, Ni3O4- and Ni4O5-) were found to exhibit dominant products resulting from the transfer of a single oxygen atom to CO, suggesting the formation of CO2. Of these four species, Ni2O3- and Ni4O5- were observed to be the most reactive having oxygen transfer products accounting for approximately 5% and 10% of the total ion intensity at a maximum pressure of 15 mTorr of CO. Our findings, therefore, indicate that anionic nickel oxide clusters containing an even number of nickel atoms and an odd number of oxygen atoms are more reactive than those with an odd number of nickel atoms and an even number of oxygen atoms. The majority of cationic nickel oxides, in contrast to anionic species, reacted preferentially through the adsorption of CO onto the cluster accompanied by the loss of either molecular O2 or nickel oxide units. The adsorption of CO onto positively charged nickel oxides, therefore, is exothermic enough to break apart the gas-phase clusters. Collision induced dissociation experiments, employing inert xenon gas, were also conducted to gain insight into the structural properties of nickel oxide clusters. The fragmentation products were found to vary considerably with size and stoichiometry as well as ionic charge state. In general, cationic clusters favored the collisional loss of molecular O2 while anionic clusters fragmented through the loss of both atomic oxygen and nickel oxide units. Our results provide insight into the effect of ionic charge state on the structure of nickel oxide clusters. Furthermore, we establish how the size and stoichiometry of nickel oxide clusters influences their ability to oxidize CO, an important reaction for environmental pollution abatement.

  14. Biodecolorization and biodegradation of Reactive Blue by ...

    SERVER

    2007-06-18

    Jun 18, 2007 ... Aspergillus sp. effectively decolorized Reactive Blue and other structurally different synthetic dyes. Agitation was found to be an important ... Few chemically different dyes such as Reactive Black (75%), Reactive Yellow (70%),. Reactive Red (33%) and ..... Degradation of azo dyes by the lignin degrading ...

  15. The effect of single and repeated prefrontal intermittent theta burst stimulation on cortical reactivity and working memory.

    Chung, Sung Wook; Rogasch, Nigel C; Hoy, Kate E; Fitzgerald, Paul B

    With an increasing interest in the use of theta burst stimulation (TBS) as a cognitive enhancer and a potential therapeutic tool for psychiatric disorders, there is a need to identify optimal parameters of TBS in the prefrontal cortex. This study examined the effect of two blocks of prefrontal intermittent TBS (iTBS) on cortical reactivity and working memory performance, compared to one block of iTBS and sham stimulation. We hypothesized that greater cortical effects would be obtained with two blocks of iTBS. Eighteen healthy participants attended three experimental sessions and received either sham, one block or two blocks of iTBS with a 15-min interval. Concurrent transcranial magnetic stimulation with electroencephalography (TMS-EEG) was used to assess the change in cortical reactivity via TMS-evoked potentials. Working memory performance was assessed using the N-back task. Cluster-based permutation statistics and two-way ANOVAs were used for neurophysiological and behavioural data, respectively. Both single and two blocks of iTBS resulted in a significant increase in the amplitude of TMS-evoked N100 and P200. No significant differences were observed between active conditions in either neurophysiological changes or working memory performance, and both failed to improve working memory performance relative to sham. Two blocks of iTBS did not result in stronger measured effects as compared to one block of iTBS. Future studies are needed to identify the optimal stimulation pattern in order to achieve a desired effect. It is also important to establish the best approach in quantifying neuromodulatory effects targeting the prefrontal cortex. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Task stressfulness moderates the effects of verbal person centeredness on cardiovascular reactivity: a dual-process account of the reactivity hypothesis.

    Bodie, Graham D

    2012-01-01

    This study sought to investigate the impact of person-centered comfort on cardiovascular reactivity and to test a recently developed dual-process theory of supportive message outcomes proposing that the impact of supportive communication is moderated by the motivation and ability to attend to message content. Participants (n = 179) completed a public speaking task that served to experimentally manipulate stress. During the preparation period, instant messages containing either low or high person-centered messages or containing no imbedded supportive message were sent. Results indicated that, in line with theoretical predictions, message content did influence mean arterial pressure and heart rate for participants exposed to moderate but not to low or high stress. Results are discussed in terms of the dual-process theory of supportive message outcomes, and the discussion offers both theoretical and practical implications of the research.

  17. Modeling hydrology and reactive transport in roads: The effect of cracks, the edge, and contaminant properties

    Apul, Defne S.; Gardner, Kevin H.; Eighmy, T. Taylor

    2007-01-01

    The goal of this research was to provide a tool for regulators to evaluate the groundwater contamination from the use of virgin and secondary materials in road construction. A finite element model, HYDRUS2D, was used to evaluate generic scenarios for secondary material use in base layers. Use of generic model results for particular applications was demonstrated through a steel slag example. The hydrology and reactive transport of contaminants were modeled in a two-dimensional cross section of a road. Model simulations showed that in an intact pavement, lateral velocities from the edge towards the centerline may transport contaminants in the base layer. The dominant transport mechanisms are advection closer to the edge and diffusion closer to the centerline. A shoulder joint in the pavement allows 0.03 to 0.45 m 3 /day of infiltration per meter of joint length as a function of the base and subgrade hydrology and the rain intensity. Scenario simulations showed that salts in the base layer of pavements are depleted by 99% in the first 20 years, whereas the metals may not reach the groundwater in 20 years at any significant concentrations if the pavement is built on adsorbing soils

  18. Antifungal Effect of Arabidopsis SGT1 Proteins via Mitochondrial Reactive Oxygen Species.

    Park, Seong-Cheol; Cheong, Mi Sun; Kim, Eun-Ji; Kim, Jin Hyo; Chi, Yong Hun; Jang, Mi-Kyeong

    2017-09-27

    The highly conserved SGT1 (suppressor of the G2 alleles of skp1) proteins from Arabidopsis are known to contribute to plant resistance to pathogens. While SGT1 proteins respond to fungal pathogens, their antifungal activity is not reported and the mechanism for this inhibition is not well understood. Therefore, recombinant Arabidopsis SGT1 proteins were cloned, expressed, and purified to evaluate their antifungal activity, resulting in their potent inhibition of pathogen growth. Dye-labeled proteins are localized to the cytosol of Candida albicans cells without the disruption of the cell membrane. Moreover, we showed that entry of the proteins into C. albicans cells resulted in the accumulation of reactive oxygen species (ROS) and cell death via altered mitochondrial potential. Morphological changes of C. albicans cells in the presence of proteins were visualized by scanning electron microscopy. Our data suggest that AtSGT1 proteins play a critical role in plant resistance to pathogenic fungal infection and they can be classified to a new plant antifungal protein.

  19. Release of Aged Contaminants from weathered sediments: Effects of sorbate speciation on scaling of reactive transport

    Chorover, Jon [Univ. of Arizona, Tucson, AZ (United States); Perdrial, Nico [Univ. of Arizona, Tucson, AZ (United States); Mueller, Karl [Pennsylvania State Univ., University Park, PA (United States); Strepka, Caleb [Pennsylvania State Univ., University Park, PA (United States); O' Day, Peggy [Univ. of California, Merced, CA (United States); Rivera, Nelson [Univ. of California, Merced, CA (United States); Um, Wooyong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chang, Hyun-Shik [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Steefel, Carl [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Thompson, Aaron [Univ. of Georgia, Athens, GA (United States)

    2012-08-14

    Hanford sediments impacted by hyperalkaline high level radioactive waste have undergone incongruent silicate mineral weathering concurrent with contaminant uptake (Chorover et al., 2008). In this project, we studied the impact of background pore water (BPW) on strontium, cesium and iodine desorption and transport in Hanford sediments that were experimentally weathered by contact with simulated hyperalkaline tank waste leachate (STWL) solutions. Using those lab-weathered Hanford sediments (HS) and model precipitates formed during nucleation from homogeneous STWL solutions (HN), we (i) provided thorough characterization of reaction products over a matrix of field-relevant gradients in contaminant concentration, PCO2, and reaction time; (ii) improved molecular-scale understanding of how sorbate speciation controls contaminant desorption from weathered sediments upon removal of caustic sources; and (iii) developed a mechanistic, predictive model of meso- to field-scale contaminant reactive transport under these conditions. Below, we provide some detailed descriptions of our results from this three year study, recently completed following a one-year no cost extension.

  20. Release of aged contaminants from weathered sediments: Effects of sorbate speciation on scaling of reactive transport

    Chorover, Jon; Perdrial, Nico; Mueller, Karl; Strepka, Caleb; O’Day, Peggy; Rivera, Nelson; Um, Wooyong; Chang, Hyun-Shik; Steefel, Carl; Thompson, Aaron

    2012-11-05

    Hanford sediments impacted by hyperalkaline high level radioactive waste have undergone incongruent silicate mineral weathering concurrent with contaminant uptake. In this project, we studied the impact of background pore water (BPW) on strontium, cesium and iodine desorption and transport in Hanford sediments that were experimentally weathered by contact with simulated hyperalkaline tank waste leachate (STWL) solutions. Using those lab-weathered Hanford sediments (HS) and model precipitates formed during nucleation from homogeneous STWL solutions (HN), we (i) provided thorough characterization of reaction products over a matrix of field-relevant gradients in contaminant concentration, partial pressure of carbon dioxide, and reaction time; (ii) improved molecular-scale understanding of how sorbate speciation controls contaminant desorption from weathered sediments upon removal of caustic sources; and (iii) developed a mechanistic, predictive model of meso- to field-scale contaminant reactive transport under these conditions. In this final report, we provide detailed descriptions of our results from this three-year study, completed in 2012 following a one-year no cost extension.

  1. Enhancing effect of marine oligotrophy on environmental concentrations of particle-reactive trace elements

    Jeffree, R.A.; Szymczak, R.

    2000-01-01

    A biogeochemical model has been previously developed that explains the inverse and nonlinear relationship between Po-210 concentration in zooplankton and their biomass, under oligotrophic conditions in French Polynesia. In this study the model structure was reviewed to determine a set of biogeochemical behaviors of Po-210, proposed to be critical to its environmental enhancement under oligotrophy: this set was then used to identify 25 other elements with comparable behaviors to Po-210. Field investigation in the Timor Sea showed that four of these a priori identified elements, viz. Cd, Co, Pb, and Mn as well as Cr and Ni, showed elevated water concentrations with reduced particle removal rates in the euphotic zone, results that are consistent with those previously obtained for Po-210 and the proposed explanatory model. These findings point to the enhanced susceptibility to contamination with particle-reactive elements of oligotrophic marine systems, whose degree and geographic extent may be enhanced by projected increases in sea surface temperatures from global warming

  2. Towards Tetraradicaloid: The Effect of Fusion Mode on Radical Character and Chemical Reactivity

    Hu, Pan

    2015-12-30

    Open-shell singlet diradicaloids display unique electronic, non-linear optical and magnetic activity and could become novel molecular materials for organic electronics, photonics and spintronics. However, design and synthesis of diradicaloids with a significant polyradical character is a challenging task for chemists. In this article, we report our efforts toward tetraradicaloid system. A series of potential tetraradicaloids by fusion of two p-quinodimethane (p-QDM) units with naphthalene or benzene rings in different modes were synthesized. Their model compounds containing one p-QDM moiety were also prepared and compared. Their ground-state structures, physical properties and chemical reactivity were systematically investigated by various exper-imental methods such as steady-state and transient absorption, two-photon absorption, X-ray crystallographic analysis, electron spin resonance, superconducting quantum interference device and electrochemistry, assisted by density functional theory calculations. It was found that their diradical and tetraradical characters show a clear dependence on the fusion mode. Upon the introducing of more five-membered rings, the diradical characters greatly decrease. This difference can be explained by the pro-aromaticity/anti-aromaticity of the molecules as well as the intramolecular charge transfer. Our comprehensive studies provide a guideline for the design and synthesis of stable open-shell singlet polycyclic hydrocarbons with significant polyradical characters.

  3. The effect of reactive ion etch (RIE) process conditions on ReRAM device performance

    Beckmann, K.; Holt, J.; Olin-Ammentorp, W.; Alamgir, Z.; Van Nostrand, J.; Cady, N. C.

    2017-09-01

    The recent surge of research on resistive random access memory (ReRAM) devices has resulted in a wealth of different materials and fabrication approaches. In this work, we describe the performance implications of utilizing a reactive ion etch (RIE) based process to fabricate HfO2 based ReRAM devices, versus a more unconventional shadow mask fabrication approach. The work is the result of an effort to increase device yield and reduce individual device size. Our results show that choice of RIE etch gas (SF6 versus CF4) is critical for defining the post-etch device profile (cross-section), and for tuning the removal of metal layers used as bottom electrodes in the ReRAM device stack. We have shown that etch conditions leading to a tapered profile for the device stack cause poor electrical performance, likely due to metal re-deposition during etching, and damage to the switching layer. These devices exhibit nonlinear I-V during the low resistive state, but this could be improved to linear behavior once a near-vertical etch profile was achieved. Device stacks with vertical etch profiles also showed an increase in forming voltage, reduced switching variability and increased endurance.

  4. Gender Differences in the Effects of Perception of Organizational Injustice on Workplace Reactivity

    Bolanle Ogungbamila

    2014-02-01

    Full Text Available Previous studies have not adequately examined, in a single model, how gender and perception of organizational injustice are related with revenge-motivated behaviors, especially in male-dominated societies. This study investigated the extent to which gender and perception of organizational injustice predicted employees’ tendencies to engage in workplace reactivity, which comprises organizational revenge, interpersonal revenge, interpersonal violence, and corruption in a sample of 703 (460 females; 243 males employees. Results of the hierarchical multiple regression indicated that gender predicted employees’ tendencies to engage in organizational revenge and interpersonal violence; with males showing higher tendencies than females. There were no gender differences in employees’ tendencies to engage in corruption and interpersonal revenge. Employees’ tendencies to engage in organizational revenge, interpersonal revenge, interpersonal violence, and corruption significantly increased with perception of organizational injustice. Females who felt unjustly treated exhibited as much organizational revenge, interpersonal revenge, interpersonal violence, and corrupt tendencies as males who felt unjustly treated. Implications for theory and research are discussed.

  5. Effects of the target aspect ratio and intrinsic reactivity onto diffusive search in bounded domains

    Grebenkov, Denis S.; Metzler, Ralf; Oshanin, Gleb

    2017-10-01

    We study the mean first passage time (MFPT) to a reaction event on a specific site in a cylindrical geometry—characteristic, for instance, for bacterial cells, with a concentric inner cylinder representing the nuclear region of the bacterial cell. A similar problem emerges in the description of a diffusive search by a transcription factor protein for a specific binding region on a single strand of DNA. We develop a unified theoretical approach to study the underlying boundary value problem which is based on a self-consistent approximation of the mixed boundary condition. Our approach permits us to derive explicit, novel, closed-form expressions for the MFPT valid for a generic setting with an arbitrary relation between the system parameters. We analyse this general result in the asymptotic limits appropriate for the above-mentioned biophysical problems. Our investigation reveals the crucial role of the target aspect ratio and of the intrinsic reactivity of the binding region, which were disregarded in previous studies. Theoretical predictions are confirmed by numerical simulations.

  6. The Effect of Reactive Oxygen Species on Embryo Quality in IVF.

    Siristatidis, Charalampos; Vogiatzi, Paraskevi; Varounis, Christos; Askoxylaki, Marily; Chrelias, Charalampos; Papantoniou, Nikolaos

    2016-01-01

    BACKROUND/AIM: Reactive oxygen species (ROS) are involved in critical biological processes in human reproduction. The aim of this study was to evaluate the association of embryo quality following in vitro fertilization (IVF), with ROS levels in the serum and follicular fluid (FF). Eighty-five participants underwent ovarian stimulation and IVF; ROS levels were measured in blood samples on the day of oocyte retrieval and in the FF from follicular aspirates using enzyme-linked immunosorbent assay. These values were associated with the quality of embryos generated. Univariable zero-inflated Poisson model revealed that ROS levels at both oocyte retrieval and in FF were not associated with the number of grade I, II, III and IV embryos (p>0.05). Age, body mass index, stimulation protocol and smoking status were not associated with the number of embryos of any grade (p>0.05). Neither ROS levels in serum nor in FF are associated with the quality of embryos produced following IVF. Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  7. Towards Tetraradicaloid: The Effect of Fusion Mode on Radical Character and Chemical Reactivity

    Hu, Pan; Lee, Sangsu; Herng, Tun Seng; Aratani, Naoki; Goncalves, Theo; Qi, Qingbiao; Shi, Xueliang; Yamada, Hiroko; Huang, Kuo-Wei; Ding, Jun; Kim, Dongho; Wu, Jishan

    2015-01-01

    Open-shell singlet diradicaloids display unique electronic, non-linear optical and magnetic activity and could become novel molecular materials for organic electronics, photonics and spintronics. However, design and synthesis of diradicaloids with a significant polyradical character is a challenging task for chemists. In this article, we report our efforts toward tetraradicaloid system. A series of potential tetraradicaloids by fusion of two p-quinodimethane (p-QDM) units with naphthalene or benzene rings in different modes were synthesized. Their model compounds containing one p-QDM moiety were also prepared and compared. Their ground-state structures, physical properties and chemical reactivity were systematically investigated by various exper-imental methods such as steady-state and transient absorption, two-photon absorption, X-ray crystallographic analysis, electron spin resonance, superconducting quantum interference device and electrochemistry, assisted by density functional theory calculations. It was found that their diradical and tetraradical characters show a clear dependence on the fusion mode. Upon the introducing of more five-membered rings, the diradical characters greatly decrease. This difference can be explained by the pro-aromaticity/anti-aromaticity of the molecules as well as the intramolecular charge transfer. Our comprehensive studies provide a guideline for the design and synthesis of stable open-shell singlet polycyclic hydrocarbons with significant polyradical characters.

  8. Reactive Systems

    Aceto, Luca; Ingolfsdottir, Anna; Larsen, Kim Guldstrand

    A reactive system comprises networks of computing components, achieving their goals through interaction among themselves and their environment. Thus even relatively small systems may exhibit unexpectedly complex behaviours. As moreover reactive systems are often used in safety critical systems......, the need for mathematically based formal methodology is increasingly important. There are many books that look at particular methodologies for such systems. This book offers a more balanced introduction for graduate students and describes the various approaches, their strengths and weaknesses, and when...... they are best used. Milner's CCS and its operational semantics are introduced, together with the notions of behavioural equivalences based on bisimulation techniques and with recursive extensions of Hennessy-Milner logic. In the second part of the book, the presented theories are extended to take timing issues...

  9. Do Executive and Reactive Disinhibition Mediate the Effects of Familial Substance Use Disorders on Adolescent Externalizing Outcomes?

    Handley, Elizabeth D.; Chassin, Laurie; Haller, Moira M.; Bountress, Kaitlin E.; Dandreaux, Danielle; Beltran, Iris

    2011-01-01

    The present study examined the potential mediating roles of executive and reactive disinhibition in predicting conduct problems, ADHD symptoms, and substance use among adolescents with and without a family history of substance use disorders. Using data from 247 high-risk adolescents, parents, and grandparents, structural equation modeling indicated that reactive disinhibition, as measured by sensation seeking, mediated the effect of familial drug use disorders on all facets of the adolescent externalizing spectrum. Executive disinhibition, as measured by response disinhibition, spatial short term memory, and “trait” impulsivity, was associated with ADHD symptoms. Moreover, although executive functioning weakness were unrelated to familial substance use disorders, adolescents with familial alcohol use disorders were at risk for “trait” impulsivity marked by a lack of planning. These results illustrate the importance of “unpacking” the broad temperament style of disinhibition and of studying the processes that underlie the commonality among facets of the externalizing spectrum and processes that that predict specific externalizing outcomes. PMID:21668077

  10. Reactivity of Nanoscale Zero-Valent Iron in Unbuffered Systems: Effect of pH and Fe(II) Dissolution.

    Bae, Sungjun; Hanna, Khalil

    2015-09-01

    While most published studies used buffers to maintain the pH, there is limited knowledge regarding the reactivity of nanoscale zerovalent iron (NZVI) in poorly buffered pH systems to date. In this work, the effect of pH and Fe(II) dissolution on the reactivity of NZVI was investigated during the reduction of 4-nitrophenol (4-NP) in unbuffered pH systems. The reduction rate increased exponentially with respect to the NZVI concentration, and the ratio of dissolved Fe(II)/initial NZVI was related proportionally to the initial pH values, suggesting that lower pH (6-7) with low NZVI loading may slow the 4-NP reduction through acceleration of the dissolution of NZVI particles. Additional experiments using buffered pH systems confirmed that high pH values (8-9) can preserve the NZVI particles against dissolution, thereby enhancing the reduction kinetics of 4-NP. Furthermore, reduction tests using ferrous ion in suspensions of magnetite and maghemite showed that surface-bound Fe(II) on oxide coatings can play an important role in enhancing 4-NP reduction by NZVI at pH 8. These unexpected results highlight the importance of pH and Fe(II) dissolution when NZVI technology is applied to poorly buffered systems, particularly at a low amount of NZVI (i.e., <0.075 g/L).

  11. EFFECT OF REACTIVE MATERIALS ON THE CONTENT OF SELECTED ELEMENTS IN INDIAN MUSTARD GROWN IN CR(VI-CONTAMINATED SOILS

    Maja Radziemska

    2016-04-01

    Full Text Available Reactive materials represent a promising agent for environmental co-remediation. The research was aimed to determine the influence of hexavalent chromium in doses of 0, 25, 50, and 150 mg Cr(VI.kg-1 of soil as well as zero valent-iron, and lignite additives on the content of macroelements in the Indian mustard (Brassica juncea L.. The average accumulation of the analysed elements in Indian mustard grown in Cr(VI contaminated soil were found to follow the decreasing order Mg>Na>P>Ca>K. Soil contamination at 150 mg Cr(VI.kg-1 of soil led to the highest increase in magnesium, calcium, sodium, and potassium content in Indian mustard. The application of zero-valent iron had a positive influence on the average Na and K content of the tested plant. The application of lignite had a positive influence on the average magnesium, sodium and calcium content in the above-ground parts of the studied plant. In the non-amended treatments (without reactive materials, the increasing rates of chromium (VI had an explicitly positive effect on the content of phosphorous and sodium in Indian mustard.

  12. Three-Week Bright-Light Intervention Has Dose-Related Effects on Threat-Related Corticolimbic Reactivity and Functional Coupling

    Fisher, Patrick M; Madsen, Martin K; Mc Mahon, Brenda

    2014-01-01

    environmental stimuli (e.g., threat) and may underlie these effects. Serotonin signaling modulates this circuit and is implicated in the pathophysiology of seasonal and other affective disorders. METHODS: We evaluated the effects of a bright-light intervention protocol on threat-related corticolimbic reactivity......-related amygdala and prefrontal reactivity in a dose-dependent manner. Conversely, amygdala-prefrontal and intraprefrontal functional coupling increased significantly in a dose-dependent manner. Genotype status significantly moderated bright-light intervention effects on intraprefrontal functional coupling....... CONCLUSIONS: This is the first study to evaluate the effects of clinically relevant bright-light intervention on threat-related brain function. We show that amygdala-prefrontal reactivity and communication are significantly affected by bright-light intervention, an effect partly moderated by genotype...

  13. Effect of In-Situ Curing on Compressive Strength of Reactive Powder Concrete

    Bali Ika

    2016-01-01

    Full Text Available A development of Reactive Powder Concrete (RPC currently is the use of quartz powder as a stabilizing agent with the content to cement ratio of 30% and steam curing method in an autoclave temperature of 250ºC which produced a high compressive strength of 180 MPa. That RPC can be generated due to one reason for using the technique of steam curing in an autoclave in the laboratory. This study proposes in-situ curing method in order the curing can be applied in the field and with a reasonable compressive strength results of RPC. As the benchmarks in this study are the curing methods in laboratory that are steam curing of 90°C for 8 hours (C1, and water curing for 28 days (C2. For the in-situ curing methods that are covering with tarpaulins and flowed steam of 3 hours per day for 7 days (C3, covering with wet sacks for 28 days (C4, and covering with wet sacks for 28 days for specimen with unwashed sand as fine aggregate (C5. The comparison of compressive strength of the specimens in this study showed compressive strength of RPC with in-situ steam curing (101.64 MPa close to the compressive strength of RPC with steam curing in the laboratory with 8.2% of different. While in-situ wet curing compared with the water curing in laboratory has the different of 3.4%. These results indicated that the proposed in-situ curing methods are reasonable good in term of the compressive strength that can be achieved.

  14. PLASMA EFFECTS ON FAST PAIR BEAMS. II. REACTIVE VERSUS KINETIC INSTABILITY OF PARALLEL ELECTROSTATIC WAVES

    Schlickeiser, R.; Krakau, S.; Supsar, M.

    2013-01-01

    The interaction of TeV gamma-rays from distant blazars with the extragalactic background light produces relativistic electron-positron pair beams by the photon-photon annihilation process. Using the linear instability analysis in the kinetic limit, which properly accounts for the longitudinal and the small but finite perpendicular momentum spread in the pair momentum distribution function, the growth rate of parallel propagating electrostatic oscillations in the intergalactic medium is calculated. Contrary to the claims of Miniati and Elyiv, we find that neither the longitudinal nor the perpendicular spread in the relativistic pair distribution function significantly affect the electrostatic growth rates. The maximum kinetic growth rate for no perpendicular spread is even about an order of magnitude greater than the corresponding reactive maximum growth rate. The reduction factors in the maximum growth rate due to the finite perpendicular spread in the pair distribution function are tiny and always less than 10 –4 . We confirm earlier conclusions by Broderick et al. and our group that the created pair beam distribution function is quickly unstable in the unmagnetized intergalactic medium. Therefore, there is no need to require the existence of small intergalactic magnetic fields to scatter the produced pairs, so that the explanation (made by several authors) for the Fermi non-detection of the inverse Compton scattered GeV gamma-rays by a finite deflecting intergalactic magnetic field is not necessary. In particular, the various derived lower bounds for the intergalactic magnetic fields are invalid due to the pair beam instability argument

  15. Ameliorative effects of low dose/low dose-rate irradiation on reactive oxygen species-related diseases model mice

    Nomura, Takaharu

    2008-01-01

    Living organisms have developed complex biological system which protects themselves against environmental radiation, and irradiation with proper dose, dose-rate and irradiation time can stimulate their biological responses against oxidative stress evoked by the irradiation. Because reactive oxygen species are involved in various human diseases, non-toxic low dose/low dose-rate radiation can be utilized for the amelioration of such diseases. In this study, we used mouse experimental models for fatty liver, nephritis, diabetes, and ageing to elucidate the ameliorative effect of low dose/low dose-rate radiation in relation to endogenous antioxidant activity. Single irradiation at 0.5 Gy ameliorates carbon tetrachloride-induced fatty liver. The irradiation increases hepatic anti-oxidative system involving glutathione and glutathione peroxidase, suggesting that endogenous radical scavenger is essential for the ameliorative effect of low dose radiation on carbon tetrachloride-induced fatty liver. Single irradiation at 0.5 Gy ameliorates ferric nitrilotriacetate-induced nephritis. The irradiation increases catalase and decreases superoxide dismutase in kidney. The result suggests that low dose radiation reduced generation of hydroxide radical generation by reducing cellular hydroperoxide level. Single irradiation at 0.5 Gy at 12 week of age ameliorates incidence of type I diabetes in non-obese diabetic (NOD) mice through the suppression of inflammatory activity of splenocytes, and resultant apoptosis of β-cells in pancreas. The irradiation activities of superoxide dismutase and catalase, which coordinately diminish intracellular reactive oxygen species. Continuous irradiation at 0.70 mGy/hr from 10 week of age elongates life span, and suppresses alopecia in type II diabetesmice. The irradiation improved glucose clearance without affecting insulin-resistance, and increased pancreatic catalase activity. The results suggest that continuous low dose-rate irradiation protect

  16. The Beta-2-Adrenoreceptor Agonists, Formoterol and Indacaterol, but Not Salbutamol, Effectively Suppress the Reactivity of Human Neutrophils In Vitro

    Ronald Anderson

    2014-01-01

    Full Text Available The clinical relevance of the anti-inflammatory properties of beta-2 agonists remains contentious possibly due to differences in their molecular structures and agonist activities. The current study has compared the effects of 3 different categories of β2-agonists, namely, salbutamol (short-acting, formoterol (long-acting and indacaterol (ultra-long-acting, at concentrations of 1–1000 nM, with human blood neutrophils in vitro. Neutrophils were activated with either N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP, 1 µM or platelet-activating factor (PAF, 200 nM in the absence and presence of the β2-agonists followed by measurement of the generation of reactive oxygen species and leukotriene B4, release of elastase, and expression of the β2-integrin, CR3, using a combination of chemiluminescence, ELISA, colorimetric, and flow cytometric procedures respectively. These were correlated with alterations in the concentrations of intracellular cyclic-AMP and cytosolic Ca2+. At the concentrations tested, formoterol and indacaterol caused equivalent, significant (P<0.05 at 1–10 nM dose-related inhibition of all of the pro-inflammatory activities tested, while salbutamol was much less effective (P<0.05 at 100 nM and higher. Suppression of neutrophil reactivity was accompanied by elevations in intracellular cAMP and accelerated clearance of Ca2+ from the cytosol of activated neutrophils. These findings demonstrate that β2-agonists vary with respect to their suppressive effects on activated neutrophils.

  17. Effect of reaction environments on the reactivity of PCB (2-chlorobiphenyl) over activated carbon impregnated with palladized iron

    Choi, Hyeok [Department of Civil Engineering, University of Texas at Arlington, 416 Yates Drive, Arlington, TX 76019-0308 (United States); Al-Abed, Souhail R., E-mail: al-abed.souhail@epa.gov [National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (United States)

    2010-07-15

    Reactive activated carbon (RAC) impregnated with palladized iron nanoparticles has been developed to treat polychlorinated biphenyls (PCBs). In this study, we evaluated the effects of various reaction environments on the adsorption-mediated dechlorination of 2-chlorobiphenyl (2-ClBP) in the RAC system. The results were discussed in close connection to the implementation issue of the RAC system for the remediation of contaminated sites with PCBs. Adsorption event of 2-ClBP onto RAC limited the overall performance under condition with a 2-ClBP/RAC mass ratio of less than 1.0 x 10{sup -4} above which dechlorination of 2-ClBP adsorbed to RAC was the reaction rate-determining step. Acidic and basic conditions were harmful to 2-ClBP adsorption and iron stability while neutral pH showed the highest adsorption-promoted dechlorination of 2-ClBP and negligible metal leaching. Coexisting natural organic matter (NOM) slightly inhibited 2-ClBP adsorption onto RAC due to the partial partitioning of 2-ClBP into NOM in the liquid phase while the 2-ClBP absorbed into NOM, which also tended to adsorb onto RAC, was less available for the dechlorination reaction. Common anions slowed down 2-ClBP adsorption but adsorbed 2-ClBP was almost simultaneously dechlorinated. Some exceptions included strong inhibitory effect of carbonate species on 2-ClBP adsorption and severe detrimental effect of sulfite on 2-ClBP dechlorination. Results on treatment of 2-ClBP spiked to actual sediment supernatants implied site-specific reactivity of RAC.

  18. Thin films of amorphous nitrogenated carbon a-CN{sub x}: Electron transfer and surface reactivity

    Tamiasso-Martinhon, P.; Cachet, H.; Debiemme-Chouvy, C.; Deslouis, C. [Universite Pierre et Marie Curie-Paris 6, Laboratoire Interfaces et Systemes Electrochimiques, CNRS, UPR15-LISE, 4 Place Jussieu, Paris F-75005 (France)

    2008-08-01

    The electrochemical behaviour of thin films of nitrogenated amorphous carbon a-CN{sub x} is similar to that of boron-doped diamond, with a wide potential window in aqueous media. They are elaborated by cathodic sputtering of a graphite target in an Ar-N{sub 2} active plasma for varying nitrogen contents, determined by XPS (0.06 {<=} x {<=} 0.39). Their electrochemical reactivity is sensitive to the surface state. The present study reports on the influence of electrochemical pre treatment on the electronic transfer rate of a fast redox system ferri-ferrocyanide, by focusing on the direction of the potential excursion. On the other hand, the role of both the pH and the potential on the interfacial capacitance in the presence of Na{sub 2}SO{sub 4} without redox species is documented. The results show up the sensitivity of the film surface to the electrochemical conditions. (author)

  19. Effects of Antisense Oligonucleotides against C-Reactive Protein on the Development of Atherosclerosis in WHHL Rabbits

    Qi Yu

    2014-01-01

    Full Text Available Increased plasma levels of C-reactive protein (CRP are closely associated with cardiovascular diseases, but whether CRP is directly involved in the pathogenesis of atherosclerosis is still under debate. Many controversial and contradictory results using transgenic mice and rabbits have been published but it is also unclear whether CRP lowering can be used for the treatment of atherosclerosis. In the current study, we examined the effects of the rabbit CRP antisense oligonucleotides (ASO on the development of atherosclerosis in WHHL rabbits. CRP ASO treatment led to a significant reduction of plasma CRP levels; however, both aortic and coronary atherosclerotic lesions were not significantly changed compared to those of control WHHL rabbits. These results suggest that inhibition of plasma CRP does not affect the development of atherosclerosis in WHHL rabbits.

  20. Effect of heat absorbing powder addition on cell morphology of porous titanium composite manufactured by reactive precursor method

    Kobashi, Makoto; Kamiya, Yoshinori; Kanetake, Naoyuki

    2012-01-01

    Open-cell structured porous titanium/ceramics composite was synthesized by a reactive precursor method using titanium and boron carbide (B 4 C) as reactant powders. Pore morphology was controlled by adding heat absorbing powder (titanium diboride: TiB 2 ) in the Ti+B 4 C blended powder. The effects of molar blending ratio of titanium and B 4 C and the amount of heat absorbing powder addition on the cell morphology (either open or closed) were investigated. Fine and homogeneous open-cell structure was achieved by adding appropriate amount of heat absorbing agent powder (>15 vol%), and the relative density of the specimen after the reaction became closer to that of the precursor by increasing TiB 2 volume fraction. When the volume fraction of TiB 2 addition was 20%, the open-cell fraction was maintained as 1.0 regardless of the relative density of the precursor.

  1. Sleep deprived and sweating it out: the effects of total sleep deprivation on skin conductance reactivity to psychosocial stress.

    Liu, Jean C J; Verhulst, Silvan; Massar, Stijn A A; Chee, Michael W L

    2015-01-01

    We examined how sleep deprivation alters physiological responses to psychosocial stress by evaluating changes in skin conductance. Between-subjects design with one group allocated to 24 h of total sleep deprivation and the other to rested wakefulness. The study took place in a research laboratory. Participants were 40 healthy young adults recruited from a university. Sleep deprivation and feedback. Electrodermal activity was monitored while participants completed a difficult perceptual task with false feedback. All participants showed increased skin conductance levels following stress. However, compared to well-rested participants, sleep deprived participants showed higher skin conductance reactivity with increasing stress levels. Our results suggest that sleep deprivation augments allostatic responses to increasing psychosocial stress. Consequentially, we propose sleep loss as a risk factor that can influence the pathogenic effects of stress. © 2014 Associated Professional Sleep Societies, LLC.

  2. Effect of plasma immersion on crystallinity of V2O5 film grown by dc reactive sputtering at room temperature

    Choi, Sun Hee; Kim, Joosun; Yoon, Young Soo

    2005-01-01

    Vanadium oxide thin films were grown at room temperature by direct current reactive sputtering. To investigate the effect of plasma immersion on the crystallinity of as-grown film, we immersed samples in plasma during the deposition process. X-ray diffraction (XRD) measurements show that as-deposited thin films immersed in plasma are crystalline, whereas those not immersed in the plasma are amorphous. Images taken with scanning electron microscopy show that the surface of films exposed to plasma have a different morphology to the surface of films not exposed to plasma. The Li-intercalation feature of as-deposited films immersed in plasma shows the typical behavior of crystalline vanadium oxide; such behavior is unsuitable for the cathode of thin film batteries (TFBs). These results indicate that direct current plasma promotes the growth of crystalline vanadium oxide films

  3. Ion Internal Excitation and Co++ 2 Reactivity: Effect On The Titan, Mars and Venus Ionospheric Chemistry

    Nicolas, C.; Zabka, J.; Thissen, R.; Dutuit, O.; Alcaraz, C.

    In planetary ionospheres, primary molecular and atomic photoions can be produced with substantial electronic and vibrational internal energy. In some cases, this is known to strongly affect both the rate constants and the branching ratio between the reac- tion products. A previous experimental study (Nicolas et al.) made at the Orsay syn- chrotron radiation facility has shown that many endothermic charge transfer reactions which were not considered in the ionospheric chemistry models of Mars, Venus and Earth have to be included because they are driven by electronic excitation of the parent ions. New measurements on two important reactions for Titan and Mars ionospheres, N+ + CH4 and O+ + CO2, will be presented. Branching ratios between products are very different when the parent atomic ions are prepared in their ground states, N+(3P) and O+(4S), or in their first electronic metastable states N+(1D) and O+(2D or P). 2 As the lifetime of these states are long enough, they survive during the mean time be- tween two collisions in the ionospheric conditions. So, the reactions of these excited states must be included in the ionospheric models. Absolute cross section measurements of the reactivity of stable doubly charged molec- ular ions CO++ and their implications for the Martian ionosphere will also be pre- 2 sented. The molecular dication CO++ production by VUV photoionisation and elec- 2 tron impact in the upper ionosphere of Mars is far from being negligible. However, to determine its concentration, it was necessary to evaluate the major loss channels of these ions. For this purpose, we measured the absolute reaction cross section of the sta- ble dications with CO2, the major neutral species of the Mars ionosphere. CO++ ions 2 were produced either by photoionisation or by electron impact, and a reaction cross section of 45 Å2 with 13CO2 was measured. The reaction leads to charge transfer or to collision induced dissociation. These results were integrated in a model

  4. Measurement of large asymptotic reactor periods from about 103 to 4.104 sec) to determine reactivity effects of small samples

    Grinevich, F.A.; Evchuk, A.I.; Klimentov, V.B.; Tyzh, A.V.; Churkin, Yu.I.; Yaroshevich, O.I.

    1977-01-01

    All investigation programs on fast reactor physics include measurements of low reactivity values (1-0.01)x10 -5 ΔK/K. An application of the pile oscillator technique for the purpose requires a special critical assembly for an installation of the oscillator. Thus it is of interest to develop relatively simple methods. In particular, one of such methods is the asymptotic period method which is widely used for low reactivity measurements. The description of the method and equipment developed for low reactivity measurements according to the measurements of the steady-state reactor period is presented. The equipment has been tested on the BTS-2 fast-thermal critical assembly. Measurement results on the reactivity effects of small samples in the fast zone centre are given. It is shown that the application of the method of measuring long steady-state periods and developed and tested equipment enables the reactivity of (1+-0.02)x10 -5 ΔK/K to be determined at the critical assembly power of 5 to 10 Wt. The disadvantage of the method presented is the time lost on reaching the steady-state period which results in greater sensitivity of the method to reactivity drifts

  5. Effects of D-cycloserine on extinction of mesolimbic cue reactivity in alcoholism: a randomized placebo-controlled trial.

    Kiefer, Falk; Kirsch, Martina; Bach, Patrick; Hoffmann, Sabine; Reinhard, Iris; Jorde, Anne; von der Goltz, Christoph; Spanagel, Rainer; Mann, Karl; Loeber, Sabine; Vollstädt-Klein, Sabine

    2015-07-01

    Mesocorticolimbic reactivity to alcohol-associated cues has been shown to be associated with relapse to renewed drinking and to be decreased by cue-exposure-based extinction training (CET). Evidence from preclinical studies suggests that the extinction of conditioned alcohol-seeking behavior might be facilitated by drugs increasing N-methyl-D-aspartate (NMDA) receptor-associated memory consolidation. In this study, we assessed the efficacy of CET treatment supplemented with the partial NMDA-receptor agonist D-cycloserine (DCS) at reducing mesolimbic cue reactivity (CR), craving, and relapse risk in alcoholism. In a randomized, placebo-controlled, double-blind study, we recruited 76 recently detoxified abstinent alcohol-dependent patients. Thirty-two (16 DCS, 16 placebo) patients showed cue-induced ventral-striatal activation measured with functional magnetic resonance imaging (fMRI) prior to treatment and were thus included in the efficacy analyses. After inpatient detoxification, patients underwent nine sessions of CET spaced over 3 weeks, receiving either 50 mg DCS or placebo 1 h prior to each CET session. FMRI was conducted before treatment and 3 weeks after treatment onset. Following treatment with CET plus DCS, cue-induced brain activation in the ventral and dorsal striatum was decreased compared to treatment with CET plus placebo. Elevated posttreatment ventral striatal CR and increased craving (assessed using the Obsessive Compulsive Drinking Scale) were associated with increased relapse risk. DCS was shown to augment the effect of CET for alcohol-dependent subjects. The interaction between craving and ventral-striatal CR on treatment outcome suggests that CET might be especially effective in patients exhibiting both high craving and elevated CR.

  6. A simple reactivity feedback model accounting for radial core expansion effects in the liquid metal fast reactor

    Kwon, Young Min; Lee, Yong Bum; Chang, Won Pyo; Haha, Do Hee

    2002-01-01

    The radial core expansion due to the structure temperature rise is one of major negative reactivity insertion mechanisms in metallic fueled reactor. Thermal expansion is a result of both the laws of nature and the particular core design and it causes negative reactivity feedback by the combination of increased core volume captures and increased core surface leakage. The simple radial core expansion reactivity feedback model developed for the SSC-K code was evaluated by the code-to-code comparison analysis. From the comparison results, it can be stated that the radial core expansion reactivity feedback model employed into the SSC-K code may be reasonably accurate in the UTOP analysis

  7. A simple reactivity feedback model accounting for radial core expansion effects in the liquid metal fast reactor

    Kwon, Young Min; Lee, Yong Bum; Chang, Won Pyo; Haha, Do Hee [KAERI, Taejon (Korea, Republic of)

    2002-10-01

    The radial core expansion due to the structure temperature rise is one of major negative reactivity insertion mechanisms in metallic fueled reactor. Thermal expansion is a result of both the laws of nature and the particular core design and it causes negative reactivity feedback by the combination of increased core volume captures and increased core surface leakage. The simple radial core expansion reactivity feedback model developed for the SSC-K code was evaluated by the code-to-code comparison analysis. From the comparison results, it can be stated that the radial core expansion reactivity feedback model employed into the SSC-K code may be reasonably accurate in the UTOP analysis.

  8. Cost-effectiveness of point-of-care C-reactive protein testing to inform antibiotic prescribing decisions

    Oppong, Raymond; Jit, Mark; Smith, Richard D; Butler, Christopher C; Melbye, Hasse; Mölstad, Sigvard; Coast, Joanna

    2013-01-01

    Background Point-of-care C-reactive protein (POCCRP) is a biomarker of inflammation that offers clinicians a rapid POC test to guide antibiotic prescribing decisions for acute cough and lower respiratory tract infections (LRTI). However, evidence that POCCRP is cost-effective is limited, particularly outside experimental settings. Aim To assess the cost-effectiveness of POCCRP as a diagnostic tool for acute cough and LRTI from the perspective of the health service. Design and setting Observational study of the presentation, management, and outcomes of patients with acute cough and LRTI in primary care settings in Norway and Sweden. Method Using hierarchical regression, data were analysed in terms of the effect on antibiotic use, cost, and patient outcomes (symptom severity after 7 and 14 days, time to recovery, and EQ-5D), while controlling for patient characteristics (self-reported symptom severity, comorbidities, and health-related quality of life) at first attendance. Results POCCRP testing is associated with non-significant positive reductions in antibiotic prescribing (P = 0.078) and increased cost (P = 0.092). Despite the uncertainty, POCCRP testing is also associated with a cost per quality-adjusted life year (QALY) gain of €9391. At a willingness-to-pay threshold of €30 000 per QALY gained, there is a 70% probability of CRP being cost-effective. Conclusion POCCRP testing is likely to provide a cost-effective diagnostic intervention both in terms of reducing antibiotic prescribing and in terms of QALYs gained. PMID:23834883

  9. Effect of Whey Supplementation on Circulating C-Reactive Protein: A Meta-Analysis of Randomized Controlled Trials

    Zhou, Ling-Mei; Xu, Jia-Ying; Rao, Chun-Ping; Han, Shufen; Wan, Zhongxiao; Qin, Li-Qiang

    2015-01-01

    Whey supplementation is beneficial for human health, possibly by reducing the circulating C-reactive protein (CRP) level, a sensitive marker of inflammation. Thus, a meta-analysis of randomized controlled trials was conducted to evaluate their relationship. A systematic literature search was conducted in July, 2014, to identify eligible studies. Either a fixed-effects model or a random-effects model was used to calculate pooled effects. The meta-analysis results of nine trials showed a slight, but no significant, reduction of 0.42 mg/L (95% CI −0.96, 0.13) in CRP level with the supplementation of whey protein and its derivates. Relatively high heterogeneity across studies was observed. Subgroup analyses showed that whey significantly lowered CRP by 0.72 mg/L (95% CI −0.97, −0.47) among trials with a daily whey dose ≥20 g/day and by 0.67 mg/L (95% CI −1.21, −0.14) among trials with baseline CRP ≥3 mg/L. Meta-regression analysis revealed that the baseline CRP level was a potential effect modifier of whey supplementation in reducing CRP. In conclusion, our meta-analysis did not find sufficient evidence that whey and its derivates elicited a beneficial effect in reducing circulating CRP. However, they may significantly reduce CRP among participants with highly supplemental doses or increased baseline CRP levels. PMID:25671415

  10. Effect of chitosan on resist printing of cotton fabrics with reactive dyes

    The concentration of chitosan, types of resist agent, curing temperature and curing time were varied to determine their effects on resist-printed cotton fabrics. An optimal chitosan concentration of 1.6% resulted in the greatest resist effect on printed cotton fabrics. For mixtures, a 6:4 ratio of citric acid : chitosan and an 8:2 ...

  11. Effect of chitosan on resist printing of cotton fabrics with reactive dyes

    user

    2011-02-21

    Feb 21, 2011 ... levels may cause the dyes to form a partial covalent bond with chitosan, thereby diminishing the resist-printing effect. In such a case, the resist printing would not be linear as a function of chitosan concentration. Red 184 exhibited the highest resist-printing effect, followed by. Blue 204 and Yellow 143.

  12. Study of thermal reactivity during bituminization of radioactive waste

    Mouffe, Sh.

    2004-10-01

    This work deals with the study of chemical reactions and phases transitions which can occur between magnesium nitrate, sodium nitrate, cobalt sulphur product, and nickel potassium ferrocyanide, when they are heated together during bituminization process of nuclear waste. The applied methodology associates a few techniques: temperature, enthalpy, and kinetics of reaction are determined by calorimetry, reaction products are characterised by chemical analyses, mass spectrometry and XRD analysis. Three fields of temperature and energy are observed in function of composition (one compound or a mixture of compounds). The study of reactions between NaNO 3 and cobalt sulphur product shows that the presence of water has got an effect on reaction temperature. The study of Mg(NO 3 ) 2 , 6 H 2 O and CoS shows an overlapping of different signals, and that the reaction rate is very slow (a few hours). (author)

  13. Acute effects of road salts and associated cyanide compounds on the early life stages of the unionid mussel Villosa iris.

    Pandolfo, Tamara J; Cope, W Gregory; Young, George B; Jones, Jess W; Hua, Dan; Lingenfelser, Susan F

    2012-08-01

    The toxicity of cyanide to the early life stages of freshwater mussels (order Unionida) has remained unexplored. Cyanide is known to be acutely toxic to other aquatic organisms. Cyanide-containing compounds, such as sodium ferrocyanide and ferric ferrocyanide, are commonly added to road deicing salts as anticaking agents. The purpose of the present study was to assess the acute toxicity of three cyanide compounds (sodium cyanide, sodium ferrocyanide, and ferric ferrocyanide), two road salts containing cyanide anticaking agents (Morton and Cargill brands), a brine deicing solution (Liquidow brand), and a reference salt (sodium chloride) on glochidia (larvae) and juveniles of the freshwater mussel Villosa iris. Sodium ferrocyanide and ferric ferrocyanide were not acutely toxic to glochidia and juvenile mussels at concentrations up to 1,000 mg/L and 100 mg/L, respectively. Lowest observed effect concentrations (LOECs) for these two chemicals ranged from 10 to >1,000 mg/L. Sodium cyanide was acutely toxic to juvenile mussels, with a 96-h median effective concentration (EC50) of 1.10 mg/L, although glochidia tolerated concentrations up to 10 mg/L. The EC50s for sodium chloride, Liquidow brine, Morton road salt, and Cargill road salt were not significantly different for tests within the same life stage and test duration (range, 1.66-4.92 g/L). These results indicate that cyanide-containing anticaking agents do not exacerbate the toxicity of road salts, but that the use of road salts and brine solutions for deicing or dust control on roads may warrant further investigation. Copyright © 2012 SETAC.

  14. Effects of Void Uncertainties on Pin Power Distributions and the Void Reactivity Coefficient for a 10X10 BWR Assembly

    Jatuff, F.; Krouthen, J.; Helmersson, S.; Chawla, R.

    2004-01-01

    A significant source of uncertainty in Boiling Water Reactor physics is associated with the precise characterisation of the axially-dependent neutron moderation properties of the coolant inside the fuel assembly channel, and the corresponding effects on reactor physics parameters such as the lattice neutron multiplication, the neutron migration length, and the pin-by-pin power distribution. In this paper, the effects of particularly relevant void fraction uncertainties on reactor physics parameters have been studied for a BWR assembly of type Westinghouse SVEA-96 using the CASMO-4, HELIOS/PRESTO-2 and MCNP4C codes. The SVEA-96 geometry is characterised by the sub-division of the assembly into four different sub-bundles by means of an inner bypass with a cruciform shape. The study has covered the following issues: (a) the effects of different cross-section data libraries on the void coefficient of reactivity, for a wide range of void fractions; (b) the effects due to a heterogeneous vs. homogeneous void distribution inside the sub-bundles; and (c) the consequences of partly inserted absorber blades producing different void fractions in different sub-bundles. (author)

  15. The reactivity of plant-derived organic matter and the potential importance of priming effects along the lower Amazon River

    Ward, Nicholas D.; Bianchi, Thomas S.; Sawakuchi, Henrique O.; Gagne-Maynard, William; Cunha, Alan C.; Brito, Daimio C.; Neu, Vania; de Matos Valerio, Aline; da Silva, Rodrigo; Krusche, Alex V.; Richey, Jeffrey E.; Keil, Richard G.

    2016-06-01

    Here we present direct measurements of the biological breakdown of 13C-labeled substrates to CO2 at seven locations along the lower Amazon River, from Óbidos to the mouth. Dark incubation experiments were performed at high and low water periods using vanillin, a lignin phenol derived from vascular plants, and at the high water period using four different 13C-labeled plant litter leachates. Leachates derived from oak wood were degraded most slowly with vanillin monomers, macrophyte leaves, macrophyte stems, and whole grass leachates being converted to CO2 1.2, 1.3, 1.7, and 2.3 times faster, respectively, at the upstream boundary, Óbidos. Relative to Óbidos, the sum degradation rate of all four leachates was 3.3 and 2.6 times faster in the algae-rich Tapajós and Xingu Rivers, respectively. Likewise, the leachates were broken down 3.2 times more quickly at Óbidos when algal biomass from the Tapajós River was simultaneously added. Leachate reactivity similarly increased from Óbidos to the mouth with leachates breaking down 1.7 times more quickly at Almeirim (midway to the mouth) and 2.8 times more quickly across the river mouth. There was no discernible correlation between in situ nutrient levels and remineralization rates, suggesting that priming effects were an important factor controlling reactivity along the continuum. Further, continuous measurements of CO2, O2, and conductivity along the confluence of the Tapajós and Amazon Rivers and the Xingu and Jarauçu Rivers revealed in situ evidence for enhanced O2 drawdown and CO2 production along the mixing zone of these confluences.

  16. Exploring electronic and steric effects on the insertion and polymerization reactivity of phosphinesulfonato pdii catalysts

    Neuwald, Boris; Falivene, Laura; Caporaso, Lucia; Cavallo, Luigi; Mecking, Stefan

    2013-01-01

    incorporation at low MA concentrations in the copolymerization; and 3) steric shielding leads to a pronounced increase in polymer molecular weight in the copolymerization. The catalyst properties induced by a given P-aryl (alkyl) moiety were combined effectively

  17. A note on the effective medium theory of random resistive-reactive medium

    Kumar, N.; Jayannavar, A.M.

    1981-06-01

    The effective medium theory for a system with randomly distributed point conductivity and polarizability is re-formulated, with attention to cross-terms involving the two disorder parameters. The treatment reveals a certain inconsistency of the conventional theory owing to the neglect of the Maxwell-Wagner effect. The results are significant for the critical resistivity and dielectric anomalies of a binary liquid mixture at the phase-separation point. (author)

  18. Effect of polyunsaturated fatty acids on the reactive oxygen and nitrogen species production by raw 264.7 macrophages

    Ambrožová, Gabriela; Pekarová, Michaela; Lojek, Antonín

    2010-01-01

    Roč. 49, č. 3 (2010), s. 133-139 ISSN 1436-6207 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : polyunsaturated fatty acids * reactive oxygen species * reactive nitrogen species Subject RIV: BO - Biophysics Impact factor: 3.343, year: 2010

  19. Microstructure and strain rate effects on the mechanical behavior of particle reinforced epoxy-based reactive materials

    White, Bradley William

    The effects of reactive metal particles on the microstructure and mechanical properties of epoxy-based composites is investigated in this work. Particle reinforced polymer composites show promise as structural energetic materials that can provide structural strength while simultaneously being capable of releasing large amounts of chemical energy through highly exothermic reactions occurring between the particles and with the matrix. This advanced class of materials is advantageous due to the decreased amount of high density inert casings needed for typical energetic materials and for their ability to increase payload expectancy and decrease collateral damage. Structural energetic materials can be comprised of reactive particles that undergo thermite or intermetallic reactions. In this work nickel (Ni) and aluminum (Al) particles were chosen as reinforcing constituents due to their well characterized mechanical and energetic properties. Although, the reactivity of nickel and aluminum is well characterized, the effects of their particle size, volume fractions, and spatial distribution on the mechanical behavior of the epoxy matrix and composite, across a large range of strain rates, are not well understood. To examine these effects castings of epoxy reinforced with 20--40 vol.% Al and 0--10 vol.% Ni were prepared, while varying the aluminum nominal particle size from 5 to 50 mum and holding the nickel nominal particle size constant at 50 mum. Through these variations eight composite materials were produced, possessing unique microstructures exhibiting different particle spatial distributions and constituent makeup. In order to correlate the microstructure to the constitutive response of the composites, techniques such as nearest-neighbor distances, and multiscale analysis of area fractions (MSAAF) were used to quantitatively characterize the microstructures. The composites were investigated under quasi-static and dynamic compressive loading conditions to characterize

  20. Humic acid effect on catalase activity and the generation of reactive oxygen species in corn (Zea mays).

    Cordeiro, Flávio Couto; Santa-Catarina, Claudete; Silveira, Vanildo; de Souza, Sonia Regina

    2011-01-01

    Humic acids (HAs) have positive effects on plant physiology, but the molecular mechanisms underlying these events are only partially understood. The induction of root growth and emission of lateral roots (LRs) promoted by exogenous auxin is a natural phenomenon. Exogenous auxins are also associated with HA. Gas nitric oxide (NO) is a secondary messenger produced endogenously in plants. It is associated with metabolic events dependent on auxin. With the application of auxin, NO production is significantly increased, resulting in positive effects on plant physiology. Thus it is possible to evaluate the beneficial effects of the application of HA as an effect of auxin. To investigate the effects of HA the parameters of root growth, Zea mays was studied by evaluating the application of 3 mM C L⁻¹ of HA extracted from Oxisol and 100 µM SNP (sodium nitroprusside) and the NO donor, subject to two N-NO₃⁻, high dose (5.0 mM N-NO₃⁻) and low dose (5.0 mM N-NO₃⁻). Treatments with HA and NO were positively increased, regardless of the N-NO₃⁻ taken, as assessed by fresh weight and dry root, issue of LRs. The effects were more pronounced in the treatment with a lower dose of N-NO₃⁻. Detection of reactive oxygen species (ROS) in vivo and catalase activity were evaluated; these tests were associated with root growth. Under application of the bioactive substances tested, detection of ROS and catalase activity increased, especially in treatments with lower doses of N-NO₃⁻. The results of this experiment indicate that the effects of HA are dependent on ROS generation, which act as a messenger that induces root growth and the emission of LRs.

  1. Effects of non-soy legume consumption on C-reactive protein: a systematic review and meta-analysis.

    Salehi-Abargouei, Amin; Saraf-Bank, Sahar; Bellissimo, Nick; Azadbakht, Leila

    2015-05-01

    Because of conflicting results of presented studies, the aim of this systematic review and meta-analysis of randomized clinical trials (RCTs) was to examine the effect of non-soy legume intake on inflammatory markers and C-reactive protein (CRP). We searched Pubmed, ISI Web of Knowledge, SCOPUS, and Google Scholar for relevant studies up to July 2013, using medical subject headings [MeSH] and other related keywords. Nine RCTs were systematically reviewed to examine the effect of non-soy legume consumption on inflammatory markers. Eight studies involving 464 participants were included in the meta-analysis. The results of the meta-analysis showed that non-soy legume consumption had a trend toward a significant effect on decreasing CRP and high-sensitivity (hs)-CRP concentrations (mean difference (MD) = -0.21; 95% confidence interval [CI], -0.44 to 0.02; P = 0.068). There was no overall effect of non-soy legume consumption on CRP or hs-CRP levels in either the parallel or crossover study designs. Our subgroup analysis of CRP type and study design, showed that non-soy legume intake had a significant effect on CRP levels in parallel studies (MD = -1.01; 95% CI, -1.78 to -0.23; P = 0.011) and a significant effect on hs-CRP levels (MD = -0.53; 95% CI, -0.95 to -0.11; P = 0.014) and in the crossover sub group (MD = -0.68; 95% CI, -1.28 to -0.08; P = 0.026). This review of RCTs showed that non-soy legume consumption may contribute to reductions in CRP and hs-CRP concentrations. However, further controlled clinical trials are needed to investigate the effect of non-soy legume intake on other inflammatory markers. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Effects of dialectical behaviour therapy-mindfulness training on emotional reactivity in borderline personality disorder: preliminary results.

    Feliu-Soler, Albert; Pascual, Juan C; Borràs, Xavier; Portella, Maria J; Martín-Blanco, Ana; Armario, Antonio; Alvarez, Enric; Pérez, Víctor; Soler, Joaquim

    2014-01-01

    Emotional dysregulation has been proposed as a hallmark of borderline personality disorder (BPD). Mindfulness techniques taught in dialectical behaviour therapy (DBT) appear to be effective in reducing affective symptoms and may enhance emotion regulation in BPD patients. In the present study, we assessed whether 10 weeks of DBT-mindfulness (DBT-M) training added to general psychiatric management (GPM) could improve emotion regulation in BPD patients. A total of 35 patients with BPD were included and sequentially assigned to GPM (n = 17) or GPM plus DBT-M (n = 18). Participants underwent a negative emotion induction procedure (presentation of standardized unpleasant images) both pre-intervention and post-intervention. Clinical evaluation was also performed before and after treatment. No differences were observed in emotional response at the post-treatment session. However, patients in the DBT-M group showed greater improvement in clinical symptoms. Formal mindfulness practice was positively correlated with clinical improvements and lower self-reported emotional reactivity. Our preliminary results suggest that mindfulness training reduces some psychiatric symptoms but may not have a clear effect on how patients respond to emotional stimuli in an experimental setting. No clear effect of mindfulness training was observed on emotional response to a negative emotion induction procedure. Application of the DBT-M module jointly to GPM induced better clinical outcomes than GPM alone. Formal mindfulness practice showed a positive impact on emotion regulation and clinical improvement. Copyright © 2013 John Wiley & Sons, Ltd.

  3. Effect of grid resolution and subgrid assumptions on the model prediction of a reactive buoyant plume under convective conditions

    Chock, D.P.; Winkler, S.L.; Pu Sun

    2002-01-01

    We have introduced a new and elaborate approach to understand the impact of grid resolution and subgrid chemistry assumption on the grid-model prediction of species concentrations for a system with highly non-homogeneous chemistry - a reactive buoyant plume immediately downwind of the stack in a convective boundary layer. The Parcel-Grid approach plume was used to describe both the air parcel turbulent transport and chemistry. This approach allows an identical transport process for all simulations. It also allows a description of subgrid chemistry. The ambient and plume parcel transport follows the description of Luhar and Britter (Atmos. Environ, 23 (1989) 1911, 26A (1992) 1283). The chemistry follows that of the Carbon-Bond mechanism. Three different grid sizes were considered: fine, medium and coarse, together with three different subgrid chemistry assumptions: micro-scale or individual parcel, tagged-parcel (plume and ambient parcels treated separately), and untagged-parcel (plume and ambient parcels treated indiscriminately). Reducing the subgrid information is not necessarily similar to increasing the model grid size. In our example, increasing the grid size leads to a reduction in the suppression of ozone in the presence of a high-NO x stack plume, and a reduction in the effectiveness of the NO x -inhibition effect. On the other hand, reducing the subgrid information (by using the untagged-parcel assumption) leads to an increase in ozone reduction and an enhancement of the NO x -inhibition effect insofar as the ozone extremum is concerned. (author)

  4. The interactive effects of excess reactive nitrogen and climate change on aquatic ecosystems and water resources of the United States

    Baron, Jill S.; Hall, E.K.; Nolan, B.T.; Finlay, J.C.; Bernhardt, E.S.; Harrison, J.A.; Chan, F.; Boyer, E.W.

    2012-01-01

    Nearly all freshwaters and coastal zones of the US are degraded from inputs of excess reactive nitrogen (Nr), sources of which are runoff, atmospheric N deposition, and imported food and feed. Some major adverse effects include harmful algal blooms, hypoxia of fresh and coastal waters, ocean acidification, long-term harm to human health, and increased emissions of greenhouse gases. Nitrogen fluxes to coastal areas and emissions of nitrous oxide from waters have increased in response to N inputs. Denitrification and sedimentation of organic N to sediments are important processes that divert N from downstream transport. Aquatic ecosystems are particularly important denitrification hotspots. Carbon storage in sediments is enhanced by Nr, but whether carbon is permanently buried is unknown. The effect of climate change on N transport and processing in fresh and coastal waters will be felt most strongly through changes to the hydrologic cycle, whereas N loading is mostly climate-independent. Alterations in precipitation amount and dynamics will alter runoff, thereby influencing both rates of Nr inputs to aquatic ecosystems and groundwater and the water residence times that affect Nr removal within aquatic systems. Both infrastructure and climate change alter the landscape connectivity and hydrologic residence time that are essential to denitrification. While Nr inputs to and removal rates from aquatic systems are influenced by climate and management, reduction of N inputs from their source will be the most effective means to prevent or to minimize environmental and economic impacts of excess Nr to the nation’s water resources.

  5. Effects of caffeine and its reactive metabolites theophylline and theobromine on the differentiating testis.

    Pollard, I; Locquet, O; Solvar, A; Magre, S

    2001-01-01

    A previous study in the rat (Pollard et al. 1990) established that caffeine, when administered during pregnancy, significantly inhibited the differentiation of the seminiferous cords and subsequent Leydig cell development in the interstitium. However, that study could not distinguish between the direct effects of caffeine and/or the intermediary secondary toxic effects of metabolites such as theophylline and theobromine. Because the fetus lacks the appropriate enzyme systems, clearance of toxic substances takes place via the placenta and maternal liver. Thus, a suitable in vitro system can effectively differentiate between primary and secondary drug effects. In the present study, 13-day-old fetal testis, at the stage of incipient differentiation, were cultured for 4 days in vitro in the presence of graded doses of caffeine, theophylline or theobromine. It was found that explants exposed to caffeine or theobromine differentiated normally, developing seminiferous cords made up of Sertoli and germ cells, soon followed by the differentiation of functionally active Leydig cells appearing in the newly formed interstitium. However, explants exposed to theophylline failed to develop seminiferous cords and, as a consequence, Leydig cells. In conclusion, insights obtained from different experimental methods, such as organ culture or whole organism studies, are not always identical. It may be prudent, therefore, to take into account that certain experimental techniques, despite providing valuable information, may require confirmation by other test methods in order to obtain an in-depth understanding of mechanisms of action involved.

  6. Sexually dimorphic effects of ancestral exposure to vinclozolin on stress reactivity in rats.

    Gillette, Ross; Miller-Crews, Isaac; Nilsson, Eric E; Skinner, Michael K; Gore, Andrea C; Crews, David

    2014-10-01

    How an individual responds to the environment depends upon both personal life history as well as inherited genetic and epigenetic factors from ancestors. Using a 2-hit, 3 generations apart model, we tested how F3 descendants of rats given in utero exposure to the environmental endocrine-disrupting chemical (EDC) vinclozolin reacted to stress during adolescence in their own lives, focusing on sexually dimorphic phenotypic outcomes. In adulthood, male and female F3 vinclozolin- or vehicle-lineage rats, stressed or nonstressed, were behaviorally characterized on a battery of tests and then euthanized. Serum was used for hormone assays, and brains were used for quantitative PCR and transcriptome analyses. Results showed that the effects of ancestral exposure to vinclozolin converged with stress experienced during adolescence in a sexually dimorphic manner. Debilitating effects were seen at all levels of the phenotype, including physiology, behavior, brain metabolism, gene expression, and genome-wide transcriptome modifications in specific brain nuclei. Additionally, females were significantly more vulnerable than males to transgenerational effects of vinclozolin on anxiety but not sociality tests. This fundamental transformation occurs in a manner not predicted by the ancestral exposure or the proximate effects of stress during adolescence, an interaction we refer to as synchronicity.

  7. Immediate and long-term effects of meditation on acute stress reactivity, cognitive functions, and intelligence.

    Singh, Yogesh; Sharma, Ratna; Talwar, Anjana

    2012-01-01

    With the current globalization of the world's economy and demands for enhanced performance, stress is present universally. Life's stressful events and daily stresses cause both deleterious and cumulative effects on the human body. The practice of meditation might offer a way to relieve that stress. The research team intended to study the effects of meditation on stress-induced changes in physiological parameters, cognitive functions, intelligence, and emotional quotients. The research team conducted the study in two phases, with a month between them. Each participant served as his own control, and the first phase served as the control for the second phase. In phase 1, the research team studied the effects of a stressor (10 minutes playing a computer game) on participants' stress levels. In phase 2, the research team examined the effects of meditation on stress levels. The research team conducted the study in a lab setting at the All India Institute of Medical Sciences (AIIMS), New Delhi, India. The participants were 34 healthy, male volunteers who were students. To study the effects of long-term meditation on stress levels, intelligence, emotional quotients, and cognitive functions participants meditated daily for 1 month, between phases 1 and 2. To study the immediate effects of meditation on stress levels, participants meditated for 15 minutes after playing a computer game to induce stress. The research team measured galvanic skin response (GSR), heart rate (HR), and salivary cortisol and administered tests for the intelligence and emotional quotients (IQ and EQ), acute and perceived stress (AS and PS), and cognitive functions (ie, the Sternberg memory test [short-term memory] and the Stroop test [cognitive flexibility]). Using a pre-post study design, the team performed this testing (1) prior to the start of the study (baseline); (2) in phase 1, after induced stress; (3) in part 1 of phase 2, after 1 month of daily meditation, and (4) in part 2 of phase 2, after

  8. The effect of ageing on fMRI: Correction for the confounding effects of vascular reactivity evaluated by joint fMRI and MEG in 335 adults

    Henson, Richard N. A.; Tyler, Lorraine K.; Davis, Simon W.; Shafto, Meredith A.; Taylor, Jason R.; Williams, Nitin; Cam‐CAN; Rowe, James B.

    2015-01-01

    Abstract In functional magnetic resonance imaging (fMRI) research one is typically interested in neural activity. However, the blood‐oxygenation level‐dependent (BOLD) signal is a composite of both neural and vascular activity. As factors such as age or medication may alter vascular function, it is essential to account for changes in neurovascular coupling when investigating neurocognitive functioning with fMRI. The resting‐state fluctuation amplitude (RSFA) in the fMRI signal (rsfMRI) has been proposed as an index of vascular reactivity. The RSFA compares favourably with other techniques such as breath‐hold and hypercapnia, but the latter are more difficult to perform in some populations, such as older adults. The RSFA is therefore a candidate for use in adjusting for age‐related changes in vascular reactivity in fMRI studies. The use of RSFA is predicated on its sensitivity to vascular rather than neural factors; however, the extent to which each of these factors contributes to RSFA remains to be characterized. The present work addressed these issues by comparing RSFA (i.e., rsfMRI variability) to proxy measures of (i) cardiovascular function in terms of heart rate (HR) and heart rate variability (HRV) and (ii) neural activity in terms of resting state magnetoencephalography (rsMEG). We derived summary scores of RSFA, a sensorimotor task BOLD activation, cardiovascular function and rsMEG variability for 335 healthy older adults in the population‐based Cambridge Centre for Ageing and Neuroscience cohort (Cam‐CAN; www.cam-can.com). Mediation analysis revealed that the effects of ageing on RSFA were significantly mediated by vascular factors, but importantly not by the variability in neuronal activity. Furthermore, the converse effects of ageing on the rsMEG variability were not mediated by vascular factors. We then examined the effect of RSFA scaling of task‐based BOLD in the sensorimotor task. The scaling analysis revealed that much of the effects

  9. Effect of vitamin E supplementation on serum C-reactive protein level: a meta-analysis of randomized controlled trials.

    Saboori, S; Shab-Bidar, S; Speakman, J R; Yousefi Rad, E; Djafarian, K

    2015-08-01

    C-reactive protein (CRP), a marker of chronic inflammation, has a major role in the etiology of chronic disease. Vitamin E may have anti-inflammatory effects. However, there is no consensus on the effects of vitamin E supplementation on CRP levels in clinical trials. The aim of this study was to systematically review randomized controlled trials (RCTs) that report on the effects of vitamin E supplementation (α- and γ-tocopherols) on CRP levels. A systematic search of RCTs was conducted on Medline and EMBASE through PubMed, Scopus, Ovid and Science Direct, and completed by a manual review of the literature up to May 2014. Pooled effects were estimated by using random-effects models and heterogeneity was assessed by Cochran's Q and I(2) tests. Subgroup analyses and meta-regression analyses were also performed according to intervention duration, dose of supplementation and baseline level of CRP. Of 4734 potentially relevant studies, only 12 trials met the inclusion criteria with 246 participants in the intervention arms and 249 participants in control arms. Pooled analysis showed a significant reduction in CRP levels of 0.62 mg/l (95% confidence interval = -0.92, -0.31; P vitamin E-treated individuals, with the evidence of heterogeneity across studies. This significant effect was maintained in all subgroups, although the univariate meta-regression analysis showed that the vitamin E supplementation dose, baseline level of CRP and duration of intervention were not the sources of the observed heterogeneity. The results of this meta-analysis suggest that supplementation with vitamin E in the form of either α-tocopherol or γ-tocopherol would reduce serum CRP levels.

  10. Effects of the Oxygenation level on Formation of Different Reactive Oxygen Species During Photodynamic Therapy

    Price, Michael; Heilbrun, Lance; Kessel, David

    2013-01-01

    We examined the effect of the oxygenation level on efficacy of two photosensitizing agents, both of which target lysosomes for photodamage but via different photochemical pathways. Upon irradiation, the chlorin termed NPe6 forms singlet oxygen in high yield while the bacteriopheophorbide WST11 forms only oxygen radicals (in an aqueous environment). Photokilling efficacy by WST11 in cell culture was impaired when the atmospheric oxygen concentration was reduced from 20% to 1%, while photokilli...

  11. Effects of Data Replication on Data Exfiltration in Mobile Ad Hoc Networks Utilizing Reactive Protocols

    2015-03-01

    aerial vehicle VANET vehicular ad hoc network VoIP Voice over Internet Protocol VRR Virtual Ring Routing xiii EFFECTS OF DATA REPLICATION ON DATA...ad hoc networks in mobile ad hoc networks (MANETs), vehicular ad hoc networks (VANETs), and flying ad hoc net- works (FANETs). Much of the research...metric, such as capacity, congestion , power, or combinations thereof. Caro refers to two different types of ants, FANTs and BANTs which are analogous to

  12. Effects of Aerobic Exercise Training on Stress Reactivity in Every-Day Life

    Haaren, Birte von

    2015-01-01

    The current thesis investigated the effects of a 20-week aerobic exercise training on physiological and emotional responses to real-life stress using a randomized, controlled trial and an inactive sample. To assess participants' physiological and psychological responses during everyday life, ambulatory assessment was used. In summary, the present thesis provides empirical support that regular exercise can lead to improved emotional and physiological responses during real-life stress.

  13. Influence of the physicochemical and aromatic properties on the chemical reactivity and its relation with carcinogenic and anticoagulant effect of 17β-aminoestrogens

    Soriano-Correa, Catalina, E-mail: socc@puma2.zaragoza.unam.mx [Química Computacional, FES-Zaragoza, Universidad Nacional Autónoma de México (UNAM), Iztapalapa, Mexico City (Mexico); Raya, Angélica [Unidad Profesional Interdisciplinaria de Ingeniería Campus Guanajuato, Instituto Politécnico Nacional (IPN), Silao de la Victoria, Guanajuato (Mexico); Barrientos-Salcedo, Carolina [Laboratorio de Química Médica y Quimiogenómica, Facultad de Bioanálisis Campus Veracruz - Boca del Río, Universidad Veracruzana, Veracruz (Mexico); Esquivel, Rodolfo O. [Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa (UAM-Iztapalapa), Mexico City (Mexico)

    2014-06-25

    Highlights: • The aromatic A-ring of 17β-aminoestrogens contribute to its anticoagulant effect. • The electron-donor substituent groups favored the basicity of 17β-aminoestrogens. • The physicochemical properties are important in the carcinogenic effect of anticoagulant molecules. - Abstract: Activity of steroid hormones is dependent upon a number of factors, as solubility, transport and metabolism. The functional differences caused by structural modifications could exert an influence on the chemical reactivity and biological effect. The goal of this work is to study the influence of the physicochemical and aromatic properties on the chemical reactivity and its relation with the carcinogenic risk that can associate with the anticoagulant effect of 17β-aminoestrogens using quantum-chemical descriptors at the DFT-B3LYP, BH and HLYP and M06-2X levels. The relative acidity of (H1) of the hydroxyl group increases with electron-withdrawing groups. Electron-donor groups favor the basicity. The steric hindrance of the substituents decreases the aromatic character and consequently diminution the carcinogenic effect. Density descriptors: hardness, electrophilic index, atomic charges, molecular orbitals, electrostatic potential and their geometric parameters permit analyses of the chemical reactivity and physicochemical features and to identify some reactive sites of 17β-aminoestrogens.

  14. Effect of Radiation on Chromospheric Magnetic Reconnection: Reactive and Collisional Multi-fluid Simulations

    Alvarez Laguna, A.; Poedts, S. [Centre for Mathematical Plasma-Astrophysics, KU Leuven, Leuven (Belgium); Lani, A.; Deconinck, H. [Aeronautics and Aerospace Department, von Karman Institute for Fluid Dynamics, Sint-Genesius-Rode (Belgium); Mansour, N. N. [NASA Ames Research Center, MS 230-3, Moffett Field, CA 94035 (United States)

    2017-06-20

    We study magnetic reconnection under chromospheric conditions in five different ionization levels from 0.5% to 50% using a self-consistent two-fluid (ions + neutrals) model that accounts for compressibility, collisional effects, chemical inequilibrium, and anisotropic heat conduction. Results with and without radiation are compared, using two models for the radiative losses: an optically thin radiation loss function, and an approximation of the radiative losses of a plasma with photospheric abundances. The results without radiation show that reconnection occurs faster for the weakly ionized cases as a result of the effect of ambipolar diffusion and fast recombination. The tearing mode instability appears earlier in the low ionized cases and grows rapidly. We find that radiative losses have a stronger effect than was found in previous results as the cooling changes the plasma pressure and the concentration of ions inside the current sheet. This affects the ambipolar diffusion and the chemical equilibrium, resulting in thin current sheets and enhanced reconnection. The results quantify this complex nonlinear interaction by showing that a strong cooling produces faster reconnections than have been found in models without radiation. The results accounting for radiation show timescales and outflows comparable to spicules and chromospheric jets.

  15. Nanoparticles in natural systems I: The effective reactive surface area of the natural oxide fraction in field samples

    Hiemstra, Tjisse; Antelo, Juan; Rahnemaie, Rasoul; van Riemsdijk, Willem H.

    2010-01-01

    Information on the particle size and reactive surface area of natural samples is essential for the application of surface complexation models (SCM) to predict bioavailability, toxicity, and transport of elements in the natural environment. In addition, this information will be of great help to enlighten views on the formation, stability, and structure of nanoparticle associations of natural organic matter (NOM) and natural oxide particles. Phosphate is proposed as a natively present probe ion to derive the effective reactive surface area of natural samples. In the suggested method, natural samples are equilibrated (⩾10 days) with 0.5 M NaHCO 3 (pH = 8.5) at various solid-solution ratios. This matrix fixes the pH and ionic strength, suppresses the influence of Ca 2+ and Mg 2+ ions by precipitation these in solid carbonates, and removes NOM due to the addition of activated carbon in excess, collectively leading to the dominance of the PO 4-CO 3 interaction in the system. The data have been interpreted with the charge distribution (CD) model, calibrated for goethite, and the analysis results in an effective reactive surface area (SA) and a reversibly bound phosphate loading Γ for a series of top soils. The oxidic SA varies between about 3-30 m 2/g sample for a large series of representative agricultural top soils. Scaling of our data to the total iron and aluminum oxide content (dithionite-citrate-bicarbonate extractable), results in the specific surface area between about 200-1200 m 2/g oxide for most soils, i.e. the oxide particles are nano-sized with an equivalent diameter in the order of ˜1-10 nm if considered as non-porous spheres. For the top soils, the effective surface area and the soil organic carbon fraction are strongly correlated. The oxide particles are embedded in a matrix of organic carbon (OC), equivalent to ˜1.4 ± 0.2 mg OC/m 2 oxide for many soils of the collection, forming a NOM-mineral nanoparticle association with an average NOM volume

  16. Neonatal Pain in Very Preterm Infants: Long-Term Effects on Brain, Neurodevelopment and Pain Reactivity

    Ruth Eckstein Grunau

    2013-10-01

    Full Text Available Effects of early life psychosocial adversity have received a great deal of attention, such as maternal separation in experimental animal models and abuse/neglect in young humans. More recently, long-term effects of the physical stress of repetitive procedural pain have begun to be addressed in infants hospitalized in neonatal intensive care. Preterm infants are more sensitive to pain and stress, which cannot be distinguished in neonates. The focus of this review is clinical studies of long-term effects of repeated procedural pain-related stress in the neonatal intensive care unit (NICU in relation to brain development, neurodevelopment, programming of stress systems, and later pain sensitivity in infants born very preterm (24–32 weeks’ gestational age. Neonatal pain exposure has been quantified as the number of invasive and/or skin-breaking procedures during hospitalization in the NICU. Emerging studies provide convincing clinical evidence for an adverse impact of neonatal pain/stress in infants at a time of physiological immaturity, rapidly developing brain microstructure and networks, as well as programming of the hypothalamic-pituitary-adrenal axis. Currently it appears that early pain/stress may influence the developing brain and thereby neurodevelopment and stress-sensitive behaviors, particularly in the most immature neonates. However, there is no evidence for greater prevalence of pain syndromes compared to children and adults born healthy at full term. In addressing associations between pain/stress and outcomes, careful consideration of confounding clinical factors related to prematurity is essential. The need for pain management for humanitarian care is widely advocated. Non-pharmacological interventions to help parents reduce their infant’s stress may be brain-protective.

  17. Calculation of effect of burnup history on spent fuel reactivity based on CASMO5

    Li Xiaobo; Xia Zhaodong; Zhu Qingfu

    2015-01-01

    Based on the burnup credit of actinides + fission products (APU-2) which are usually considered in spent fuel package, the effect of power density and operating history on k_∞ was studied. All the burnup calculations are based on the two-dimensional fuel assembly burnup program CASMO5. The results show that taking the core average power density of specified power plus a bounding margin of 0.0023 to k_∞, and taking the operating history of specified power without shutdown during cycle and between cycles plus a bounding margin of 0.0045 to k_∞ can meet the bounding principle of burnup credit. (authors)

  18. Effects of reactive filters based on modified zeolite in dairy industry wastewater treatment process

    Kolaković Srđan

    2013-01-01

    Full Text Available Application of adsorbents based on organo-zeolites has certain advantages over conventional methods applied in food industry wastewater treatment process. The case study presented in this paper examines the possibilities and effects of treatment of dairy industry wastewater by using adsorbents based on organo-zeolites. The obtained results indicate favorable filtration properties of organo-zeolite, their high level of adsorption of organic matter and nitrate nitrogen in the analyzed wastewater. This paper concludes with recommendations of optimal technical and technological parameters for the application of these filters in practice.

  19. Reactivity and effectiveness of traditional and novel ligands for multi-micronutrient fertilization in a calcareous soil.

    López-Rayo, Sandra; Nadal, Paloma; Lucena, Juan J

    2015-01-01

    This study compares the effectiveness of multi-micronutrient formulations containing iron (Fe), manganese (Mn), and zinc (Zn) with traditional (EDTA, DTPA, HEEDTA, and EDDHAm) or novel chelates (o,p-EDDHA, S,S-EDDS, and IDHA) and natural complexing agents (gluconate and lignosulfonate). The stability and reactivity of the formulations were studied on batch experiments with calcareous soil and by speciation modeling. Formulations containing traditional ligands maintained higher Mn but lower Zn concentration in soil solution than the novel ligands. The gluconate and lignosulfonate maintained low concentrations of both Mn and Zn in soil solution. Selected formulations were applied into calcareous soil and their efficacy was evaluated in a pot experiment with soybean. The formulation containing DTPA led to the highest Zn concentration in plants, as well as the formulation containing S,S-EDDS in the short-term, which correlated with its biodegradability. The application of traditional or novel ligands in formulations did not result in sufficient plant Mn concentrations, which was related to the low Mn stability observed for all formulations under moderate oxidation conditions. The results highlight the need to consider the effect of metals and ligands interactions in multi-nutrient fertilization and the potential of S,S-EDDS to be used for Zn fertilization. Furthermore, it is necessary to explore new sources of Mn fertilization for calcareous soils that have greater stability and efficiency, or instead to use foliar fertilization.

  20. Reactivity and effectiveness of traditional and novel ligands for multi-micronutrient fertilization in a calcareous soil

    Sandra eLópez-Rayo

    2015-09-01

    Full Text Available This study compares the effectiveness of multi-micronutrient formulations containing Fe, Mn, and Zn with traditional (EDTA, DTPA, HEEDTA, EDDHAm or novel chelates (o,p-EDDHA, S,S-EDDS, IDHA and natural complexing agents (gluconate and lignosulfonate. The stability and reactivity of the formulations were studied on batch experiments with calcareous soil and by speciation modeling. Formulations containing traditional ligands maintained higher Mn but lower Zn concentration in soil solution than the novel ligands. The gluconate and lignosulfonate maintained low concentrations of both Mn and Zn in soil solution. Selected formulations were applied into calcareous soil and their efficacy was evaluated in a pot experiment with soybean. The formulation containing DTPA led to the highest Zn concentration in plants, as well as the formulation containing S,S-EDDS in the short-term, which correlated with its biodegradability. The application of traditional or novel ligands in formulations did not result in sufficient plant Mn concentrations, which was related to the low Mn stability observed for all formulations under moderate oxidation conditions. The results highlight the need to consider the effect of metals and ligands interactions in multi-nutrient fertilization and the potential of S,S-EDDS to be used for Zn fertilization. Furthermore, it is necessary to explore new sources of Mn fertilization for calcareous soils that have greater stability and efficiency, or instead to use foliar fertilization.

  1. The effects of quercetin towards reactive oxygen species levels and glutathione in Toxoplasma gondii profilin-exposed adipocytes in vitro

    Yulia D.S.

    2018-04-01

    Full Text Available Toxoplasma gondii (T. gondii has been found to potentially cause adipocyte dysfunction by activating the inflammatory pathways through its profilin. In response to inflammation, adipocytes produce Reactive Oxygen Species (ROS. To scavenge ROS, endogenous or exogenous antioxidants are required. Glutathione (GSH is one of enzimatic antioxidant that abundant in all of body cells. Quercetin, an exogenous antioxidant, can be widely found in natural products. This research aims to explore the effects of quercetin towards ROS and GSH stimulated from T. gondii profilin-exposed adipocytes. To achieve this, adipocytes were exposed to 20 µM T. gondii profilin and treated with four doses of quercetin; 31.25, 62.5, 125, and 250 µM. The results showed that quercetin significantly reduced the ROS levels (p <0,001 and significantly increased GSH (p <0,001 in T. gondii profilin-exposed adipocytes compared to untreated cells, with an effective dose of 62.5µM. This study implies that quercetin might be a promising candidate for development of antioxidant treatment interventions to prevent toxoplasmosis-mediated adipocytopathy.

  2. Reactivity and effectiveness of traditional and novel ligands for multi-micronutrient fertilization in a calcareous soil

    López-Rayo, Sandra; Nadal, Paloma; Lucena, Juan J.

    2015-01-01

    This study compares the effectiveness of multi-micronutrient formulations containing iron (Fe), manganese (Mn), and zinc (Zn) with traditional (EDTA, DTPA, HEEDTA, and EDDHAm) or novel chelates (o,p-EDDHA, S,S-EDDS, and IDHA) and natural complexing agents (gluconate and lignosulfonate). The stability and reactivity of the formulations were studied on batch experiments with calcareous soil and by speciation modeling. Formulations containing traditional ligands maintained higher Mn but lower Zn concentration in soil solution than the novel ligands. The gluconate and lignosulfonate maintained low concentrations of both Mn and Zn in soil solution. Selected formulations were applied into calcareous soil and their efficacy was evaluated in a pot experiment with soybean. The formulation containing DTPA led to the highest Zn concentration in plants, as well as the formulation containing S,S-EDDS in the short-term, which correlated with its biodegradability. The application of traditional or novel ligands in formulations did not result in sufficient plant Mn concentrations, which was related to the low Mn stability observed for all formulations under moderate oxidation conditions. The results highlight the need to consider the effect of metals and ligands interactions in multi-nutrient fertilization and the potential of S,S-EDDS to be used for Zn fertilization. Furthermore, it is necessary to explore new sources of Mn fertilization for calcareous soils that have greater stability and efficiency, or instead to use foliar fertilization. PMID:26442065

  3. Effects of oxygen contents on the electrochromic properties of tungsten oxide films prepared by reactive magnetron sputtering

    Lu, H.-H.

    2008-01-01

    The electrochromism have been extensively investigated due to their potential applications such as smart window of architecture and automobile glazing to save energy and modulate the transmittance of light and solar radiation. The objective of this study is to investigate the effects of sputtering conditions on the microstructure and electrochromic properties of tungsten oxide films prepared by dc reactive magnetron sputtering. Experimental results showed that the deposition rate of WO 3-y films decreased with increasing oxygen flow rate. XRD and Raman spectra analysis suggests that the WO 3-y films deposited at various oxygen flow rates are poor crystallinity or amorphous. The transmission change between colored and bleached states at a wavelength of 550 nm was 61.4% as the oxygen content was 60%. The coloration efficiency slightly increases with increasing oxygen flow rate in the low oxygen content region and reaching a maximum value of 38.94 cm 2 /C at 60% oxygen content. In addition, the films deposited at 60% oxygen content showed a good reversibility. The effects of lithium ions intercalated on the transmission of WO 3-y films were also discussed

  4. The Buffer Effect of Therapy Dog Exposure on Stress Reactivity in Undergraduate Students

    Alexandra J. Fiocco

    2017-06-01

    Full Text Available Stress is an insidious health risk that is commonly reported among university students. While research suggests that dog exposure may facilitate recovery from a stress response, little is known about the buffer effect of dog exposure on the stress response to a future stressor. This study examined whether interaction with a therapy dog could reduce the strength of the physiological stress response when exposed to a subsequent stressor. Sixty-one university students were randomly assigned to either a therapy dog (TD, n = 31 or a no-dog control (C, n = 30 group. The stress response was measured by electrodermal activity (EDA in response to the Paced Auditory Serial Addition Test (PASAT. Participants also completed questionnaires that assessed pet attitude, general stress levels, and affect. Analyses of covariance (ANCOVAs showed that increase in EDA was significantly more pronounced in the C group than in the TD group (p < 0.01. Pet attitudes did not modulate the buffer effect of therapy dog exposure. Results suggest that therapy dog exposure may buffer the stress response in university students, which has implications for the promotion of a viable stress management program on university campuses.

  5. Early childhood cortisol reactivity moderates the effects of parent-child relationship quality on the development of children’s temperament in early childhood

    Kopala-Sibley, Daniel C.; Dougherty, Lea R.; Dyson, Margret W.; Laptook, Rebecca S.; Olino, Thomas M.; Bufferd, Sara J.; Klein, Daniel N.

    2017-01-01

    Positive parenting has been related both to lower cortisol reactivity and more adaptive temperament traits in children, whereas elevated cortisol reactivity may be related to maladaptive temperament traits, such as higher negative emotionality (NE) and lower positive emotionality (PE). However, no studies have examined whether hypothalamic-pituitary-adrenal axis activity, as measured by cortisol reactivity, moderates the effect of the quality of the parent-child relationship on changes in temperament in early childhood. In this study, 126 3-year olds were administered the Laboratory Temperament Assessment Battery (Lab-TAB; Goldsmith et al., 1995) as a measure of temperamental NE and PE. Salivary cortisol was collected from the child at 4 time points during this task. The primary parent and the child completed the Teaching Tasks battery (Egeland et al., 1995), from which the quality of the relationship was coded. At age 6, children completed the Lab-TAB again. From age 3 to 6, adjusting for age 3 PE or NE, a better quality relationship with their primary parent predicted decreases in NE for children with elevated cortisol reactivity and predicted increases in PE for children with low cortisol reactivity. Results have implications for our understanding of the interaction of biological stress systems and the parent-child relationship in the development of temperament in childhood. PMID:26689860

  6. Effects of several types of biomass fuels on the yield, nanostructure and reactivity of soot from fast pyrolysis at high temperatures

    Trubetskaya, Anna; Jensen, Peter Arendt; Jensen, Anker Degn

    2016-01-01

    This study presents the effect of biomass origin on the yield, nanostructure and reactivity of soot. Soot was produced from wood and herbaceous biomass pyrolysis at high heating rates and at temperatures of 1250 and 1400 °C in a drop tube furnace. The structure of solid residues was characterized...

  7. Age-dependent effects of acute methylphenidate on amygdala reactivity in stimulant treatment-naive patients with Attention Deficit/Hyperactivity Disorder

    Bottelier, Marco A.; Schrantee, Anouk; Ferguson, Bart; Tamminga, Hyke G. H.; Bouziane, Cheima; Kooij, J. J. Sandra; de Ruiter, Michiel B.; Reneman, Liesbeth

    2017-01-01

    In the present study, we investigate whether methylphenidate (MPH) affects emotional processing and whether this effect is modulated by age. We measured amygdala reactivity with functional Magnetic Resonance Imaging (fMRI) during processing of angry and fearful facial expressions in male stimulant

  8. The effect of HLA mismatches, shared cross-reactive antigen groups, and shared HLA-DR antigens on the outcome after pediatric liver transplantation

    Sieders, E; Hepkema, BG; Peeters, PMJG; Ten Vergert, EM; De Jong, KP; Porte, RJ; Bijleveld, CMA; van den Berg, AP; Lems, SPM; Gouw, ASH; Slooff, MJH

    2005-01-01

    The aim of this study was to analyze the effect of human leukocyte antigen (HLA) class I and HLA-DR mismatching, sharing cross-reactive antigen groups (CREGs), and sharing HLA-DR antigens on the outcome after pediatric liver transplantation. Outcome parameters were graft survival, acute rejection,

  9. Effects of family cohesion, and heart rate reactivity on aggressive/rule-breaking behavior and prosocial behavior in adolescence : The TRAILS study

    Sijtsema, Jelle; Nederhof, Esther; Veenstra, René; Ormel, Johan; Oldehinkel, Tineke; Ellis, Bruce J.

    The biological sensitivity to context hypothesis posits that high physiological reactivity (i.e., increases in arousal from baseline) constitutes heightened sensitivity to environmental influences, for better or worse. To test this hypothesis, we examined the interactive effects of family cohesion

  10. The effect of FR enhancement in reactive ion beam sputtered Bi, Gd, Al-substituted iron- garnets: Bi2O3 nanocomposite films

    Berzhansky, V.; Shaposhnikov, A.; Karavainikov, A.; Prokopov, A.; Mikhailova, T.; Lukienko, I.; Kharchenko, Yu.; Miloslavskaya, O.; Kharchenko, N.

    2012-01-01

    The effect of considerable Faraday rotation (FR) and figure of merit (Q) enhancement in Bi, Gd, Al-substituted iron garnets: Bi2O3 nano-composite films produced by separate reactive ion beam sputtered Bi:YIG and Bi2O3 films was found. It reached threefold enhancement of the FR and twofold of the Q one on GGG substrates.

  11. The effect of interlayer anion on the reactivity of Mg-Al layered double hydroxides: improving and extending the customization capacity of anionic clays.

    Rojas, Ricardo; Bruna, Felipe; de Pauli, Carlos P; Ulibarri, M Ángeles; Giacomelli, Carla E

    2011-07-01

    Layered double hydroxides (LDHs) reactivity and interfacial behavior are closely interconnected and control particle properties relevant to the wide range of these solids' applications. Despite their importance, their relationship has been hardly described. In this work, chloride and dodecylsulfate (DDS(-)) intercalated LDHs are studied combining experimental data (electrophoretic mobility and contact angle measurements, hydroxyl and organic compounds uptake) and a simple mathematical model that includes anion-binding and acid-base reactions. This approach evidences the anion effect on LDHs interfacial behavior, reflected in the opposite particle charge and the different surface hydrophobic/hydrophilic character. LDHs reactivity are also determined by the interlayer composition, as demonstrated by the cation uptake capability of the DDS(-) intercalated sample. Consequently, the interlayer anion modifies the LDHs interfacial properties and reactivity, which in turn extends the customization capacity of these solids. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Hydroconversion of coal tars: effect of the temperature of pyrolysis on the reactivity of tars

    Lemberton, J.L.; Touzeyidio, M.; Guisnet, M.

    1988-12-01

    The hydroconversion of a low-temperature and of a high-temperature tar was carried out in the presence of a sulfided Ni and Mo on alumina catalyst - pure or mixed with an acid catalyst (HY zeolite). Significant amounts of light products can be obtained from low temperature tar, formed however through a non-catalytic process. On the contrary, there is a slight catalytic effect during the hydroprocessing of high temperature tar, but the yield in light products is very low. These results can be explained by an extensive poisoning of the NiMo on alumina catalyst by coke which is initiated by the O- and N-containing compounds of the tars. 10 refs., 1 fig., 3 tabs.

  13. Long-Term Effects of Neonatal Pain and Stress on Reactivity of the Nociceptive System.

    Butkevich, I P; Mikhailenko, V A

    2016-10-01

    The influence of inflammatory pain and/or weaning stress at different terms of neonatal development on functional activity of the nociceptive system during adulthood was studied in rats. Repeated stress in 1-2-day-old rat pups (a premature baby model) enhanced pain sensitivity to peripheral inflammation in both males and females. Repeated inflammatory pain experienced by male pups aged 1-2 or 7-8 days (models of preterm and full-term baby), even in presence of mother, enhanced pain behavior under conditions of repeated inflammatory pain in adulthood. Pain sensitivity in adult animals before (hot plate test) and after formation of the inflammatory focus (formalin test) depended on the age when the animals were subjected to the injury, type of exposure, and on animal sex. The priority data obtained by us will help to understand the mechanisms of long-term effects of early injuries and are important for pediatricians and neonatologists.

  14. Reactivity effect of poisoned beryllium block shuffling in the MARIA reactor

    Andrzejewski, K.; Kulikowska, T.

    2000-01-01

    The paper is a continuation of the analysis of beryllium blocks poisoning by Li-6 and He-3 in the MARIA reactor, presented at the 22 RERTR Meeting in Budapest. A new computational tool, the REBUS-3 code, has been used for predicting the amount of poison. The code has been put into operation on a HP computer and the beryllium transmutation chains have been activated with assistance of the ANL RERTR staff. The horizontal and vertical poison distribution within beryllium blocks has been studied. A simple shuffling of beryllium blocks has been simulated to check the effect of exchanging a block with high poison concentration, adjacent to fuel elements, with a peripheral one with a low poison concentration

  15. Effects of hypercapnia on peripheral vascular reactivity in elderly patients with acute exacerbation of chronic obstructive pulmonary disease

    de Matthaeis A

    2014-05-01

    Full Text Available Angela de Matthaeis,1 Antonio Greco,2,* Mariangela Pia Dagostino,2 Giulia Paroni,2 Andrea Fontana,3 Manlio Vinciguerra,1,4,5 Gianluigi Mazzoccoli,1,* Davide Seripa,2 Gianluigi Vendemiale61Division of Internal Medicine and Chronobiology Unit, 2Geriatrics Unit and Gerontology, Geriatrics Research Laboratory, Department of Medical Sciences, 3Unit of Biostatistics, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Foggia, 4Euro-Mediterranean Institute of Sciences and Technology, Palermo, Italy; 5University College London, Institute for Liver and Digestive Health, Division of Medicine, Royal Free Campus, London, UK; 6Geriatrics Unit, University of Foggia, Foggia, Italy*These authors contributed equally to this workAbstract: Blood acid-base imbalance has important effects on vascular reactivity, which can be related to nitric oxide (NO concentration and increased during hypercapnia. Release of NO seems to be linked to H+ and CO2 concentration and to exacerbation of chronic obstructive pulmonary disease (COPD, a common medical condition in the elderly. Flow-mediated dilation (FMD, a valuable cardiovascular risk indicator, allows assessment of endothelial-dependent vasodilation, which is to a certain extent mediated by NO. We investigated the effects of hypercapnia and acid-base imbalance on endothelial-dependent vasodilation by measurement of FMD in 96 elderly patients with acute exacerbation of COPD. Patients underwent complete arterial blood gas analysis and FMD measurement before (phase 1 and after (phase 2 standard therapy for acute exacerbation of COPD and recovery. Significant differences between phase 1 and phase 2 were observed in the mean values of pH (7.38±0.03 versus 7.40±0.02, P<0.001, pO2 (59.6±4.9 mmHg versus 59.7±3.6 mmHg, P<0.001, pCO2 (59.3±8.63 mmHg versus 46.7±5.82 mmHg, P<0.001, FMD (10.0%±2.8% versus 8.28%±2.01%, P<0.001 and blood flow rate (1.5±0.3 m/s versus 1.5±0.3 m/s, P=0.001. FMD values were

  16. The Buffer Effect of Therapy Dog Exposure on Stress Reactivity in Undergraduate Students.

    Fiocco, Alexandra J; Hunse, Anastasia M

    2017-06-30

    Stress is an insidious health risk that is commonly reported among university students. While research suggests that dog exposure may facilitate recovery from a stress response, little is known about the buffer effect of dog exposure on the stress response to a future stressor. This study examined whether interaction with a therapy dog could reduce the strength of the physiological stress response when exposed to a subsequent stressor. Sixty-one university students were randomly assigned to either a therapy dog (TD, n = 31) or a no-dog control (C, n = 30) group. The stress response was measured by electrodermal activity (EDA) in response to the Paced Auditory Serial Addition Test (PASAT). Participants also completed questionnaires that assessed pet attitude, general stress levels, and affect. Analyses of covariance (ANCOVAs) showed that increase in EDA was significantly more pronounced in the C group than in the TD group ( p stress response in university students, which has implications for the promotion of a viable stress management program on university campuses.

  17. Water dissociation on Ni(100) and Ni(111): Effect of surface temperature on reactivity

    Seenivasan, H.; Tiwari, Ashwani K.

    2013-01-01

    Water adsorption and dissociation on Ni(100) and Ni(111) surfaces are studied using density functional theory calculations. Water adsorbs on top site on both the surfaces, while H and OH adsorb on four fold hollow and three fold hollow (fcc) sites on Ni(100) and Ni(111), respectively. Transition states (TS) on both surfaces are identified using climbing image-nudged elastic band method. It is found that the barrier to dissociation on Ni(100) surface is slightly lower than that on Ni(111) surface. Dissociation on both the surfaces is exothermic, while the exothermicity on Ni(100) is large. To study the effect of lattice motion on the energy barrier, TS calculations are performed for various values of Q (lattice atom coordinate along the surface normal) and the change in the barrier height and position is determined. Calculations show that the energy barrier to reaction decreases with increasing Q and increases with decreasing Q on both the surfaces. Dissociation probability values at different surface temperatures are computed using semi-classical approximation. Results show that the influence of surface temperature on dissociation probability on the Ni(100) is significantly larger compared to that of Ni(111). Moreover, on Ni(100), a dramatic shift in energy barrier to lower incident energy values is observed with increasing surface temperature, while the shift is smaller in the case of Ni(111)

  18. Effects of the oxygenation level on formation of different reactive oxygen species during photodynamic therapy.

    Price, Michael; Heilbrun, Lance; Kessel, David

    2013-01-01

    We examined the effect of the oxygenation level on efficacy of two photosensitizing agents, both of which target lysosomes for photodamage, but via different photochemical pathways. Upon irradiation, the chlorin termed NPe6 forms singlet oxygen in high yield while the bacteriopheophorbide WST11 forms only oxygen radicals (in an aqueous environment). Photokilling efficacy by WST11 in cell culture was impaired when the atmospheric oxygen concentration was reduced from 20% to 1%, while photokilling by NPe6 was unaffected. Studies in a cell-free system revealed that the rates of photobleaching of these agents, as a function of the oxygenation level, were correlated with results described above. Moreover, the rate of formation of oxygen radicals by either agent was more sensitive to the level of oxygenation than was singlet oxygen formation by NPe6. These data indicate that the photochemical process that leads to oxygen radical formation is more dependent on the oxygenation level than is the pathway leading to formation of singlet oxygen. © 2013 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2013 The American Society of Photobiology.

  19. Effect of Pressure and Heat Treatments on the Compressive Strength of Reactive Powder Concrete

    Helmi Masdar

    2018-01-01

    Full Text Available This paper presents the corresponding compressive strength of RPC with variable pressure combined with heating rate, heating duration, and starting time of heating. The treatments applied were 8 MPa static pressure on fresh RPC prims and heat curing at 240 °C in an oven. The compressive strength test was conducted at 7-d and 28-d. The images of RPC morphology were captured on the surface of a fractured specimen using Scanning Electron Microscopy in Secondary Electron detector mode to describe pore filing mechanism after treatments. The results show that a heating rate at 50 °C/hr resulted in the highest compressive strength about 40 % more than those at 10 or 100 °C/hr. A heating duration of 48 hours led to the maximum compressive strength. Heat curing applied 2 days after casting resulted in the maximum compressive. Heat curing had a signicant effect on the compresssive strength due to the acceleration of both reactions (hydration and pozzolanic and the degree of transformation from tobermorite to xonotlite. It is concluded that the optimum condition of treatments is both pressure and heat curing at 2-day after casting with a rate of 50 °C/hr for 48 hours.

  20. Regarding KUR Reactivity Measurement System

    Nakamori, Akira; Hasegawa, Kei; Tsuchiyama, Tatsuo; Yamamoto, Toshihiro; Okumura, Ryo; Sano, Tadafumi

    2012-01-01

    This article reported: (1) the outline of the reactivity measurement system of Kyoto University Research Reactor (KUR), (2) the calibration data of control rod, (3) the problems and the countermeasures for range switching of linear output meter. For the laptop PC for the reactivity measurement system, there are four input signals: (1) linear output meter, (2) logarithmic output meter, (3) core temperature gauge, and (4) control rod position. The hardware of reactivity measurement system is controlled with Labview installed on the laptop. Output, reactivity, reactor period, and the change in reactivity due to temperature effect or Xenon effect are internally calculated and displayed in real-time with Labview based on the four signals above. Calculation results are recorded in the form of a spreadsheet. At KUR, the reactor core arrangement was changed, so the control rod was re-calibrated. At this time, calculated and experimental values of reactivity based on the reactivity measurement system were compared, and it was confirmed that the reactivity calculation by Labview was accurate. The range switching of linear output meter in the nuclear instrumentation should automatically change within the laptop, however sometimes this did not function properly in the early stage. It was speculated that undefined percent values during the transition of percent value were included in the calculation and caused calculation errors. The range switching started working properly after fixing this issue. (S.K.)