Science.gov

Sample records for mild aqueous conditions

  1. Hydrodefluorination and hydrogenation of fluorobenzene under mild aqueous conditions.

    PubMed

    Baumgartner, Rebekka; McNeill, Kristopher

    2012-09-18

    Fluorinated organic compounds are increasingly used in many applications, and their release to the environment is expected. It is therefore important to find suitable methods for degradation of fluorinated compounds under environmentally relevant conditions. In this study, a simple heterogeneous rhodium-based catalytic system (Rh/Al(2)O(3) and H(2)) for hydrodefluorination and hydrogenation of fluorobenzene under mild aqueous conditions (1 atm of H(2), ambient temperature) was developed and the underlying reaction mechanism was investigated. Fluorobenzene degraded rapidly (t(1/2) ≈ 0.2 h) to form cyclohexane and fluoride (F(-)) as the stable end products, with benzene and cyclohexene observed as intermediates. Cyclohexadiene intermediates were not observed but were expected to form during the hydrogenation of benzene. Three postulated but unobserved fluorinated intermediates were subjected to the catalytic reaction conditions, and it was concluded that they most likely do not form during the fluorobenzene degradation reaction. Isotope labeling experiments showed that the unsaturated intermediates undergo rapid and reversible hydrogenation/dehydrogenation under the reaction conditions and also that fully saturated compounds are unreactive in the catalytic system. Both molecular hydrogen and water were sources of hydrogen in the final cyclohexane product. Kinetic fitting indicated that sorption/desorption of fluorobenzene onto the catalyst surface plays an important role in the mechanism. PMID:22871102

  2. Sulfur removal from Gediz lignite using aqueous sodium hydroxide solutions under mild oxidative conditions

    SciTech Connect

    Yaman, S.; Kuecuekbayrak, S.

    1999-11-01

    Sulfur removal from a high-sulfur Turkish lignite (Gediz) using aqueous sodium hydroxide solutions having dissolved oxygen was investigated under mild oxidative conditions. Effects of the parameters such as sodium hydroxide/lignite weight ratio, temperature, and partial pressure of oxygen were investigated within the ranges of 0.05--0.8, 423--498 K, and 1--2 MPa, respectively. Optimum values of these parameters were determined regarding sulfur removal and coal recovery. Influences of dry oxidation of the lignite sample as a pretreatment at 573 K and subsequent washing of some treated lignite samples with 1 N HCl were investigated.

  3. Promoted oxidation of phenol in aqueous solution using molecular oxygen at mild conditions

    SciTech Connect

    Vogel, F.; Harf, J.; Hug, A.; Rohr, P.R. von

    1999-05-01

    Wet oxidation with molecular oxygen at mild conditions (temperature < 200 C, pressure {le} 2 MPa) is an economically attractive pretreatment step for non-biodegradable aqueous waste streams. In order to overcome the low reactivity of molecular oxygen towards organic molecules at these mild process conditions, an initiator was used in combination with ferrous ions in the acidic range. The promoted oxidation of phenol in aqueous solution was investigated in a 4 liters stirred autoclave. It was possible to degrade the phenol at temperatures as low as 100 C without observing an induction time. The remaining solution contained mainly acetic and formic acid and was well biodegradable. The oxidative behavior of the oxygen/phenol system could be explained using the well-known autoxidation mechanism for aliphatic molecules. 4-hydroperoxy-phenol is suggested as a key intermediate. Measured products are p-benzoquinone, hydroquinone, catechol, maleic, oxalic, pyruvic, formic, and acetic acid. Dimers could also be identified in sample extracts. A global pathway including all identified products is presented.

  4. Kinetics of organic transformations under mild aqueous conditions: implications for the origin of life and its metabolism

    NASA Technical Reports Server (NTRS)

    Weber, Arthur L.

    2004-01-01

    The rates of thermal transformation of organic molecules containing carbon, hydrogen, and oxygen were systematically examined in order to identify the kinetic constraints that governed origin-of-life organic chemistry under mild aqueous conditions. Arrhenius plots of the kinetic data were used to estimate the reaction of half-lifes at 50 degrees C. This survey showed that hydrocarbons and organic substances containing a single oxygenated group were kinetically the most stable; whereas organic substances containing two oxygenated groups in which one group was an alpha- or beta-positioned carbonyl group were the most reactive. Compounds with an alpha- or beta-positioned carbonyl group (aldehyde or ketone) had rates of reaction that were up to 10(24)-times faster than rates of similar molecules lacking the carbonyl group. This survey of organic reactivity, together with estimates of the molecular containment properties of lipid vesicles and liquid spherules, indicates that an origins process in a small domain that used C,H,O-intermediates had to be catalytic and use the most reactive organic molecules to prevent escape of its reaction intermediates.

  5. Kinetics of Organic Transformations Under Mild Aqueous Conditions: Implications for the Origin of Life and Its Metabolism

    NASA Technical Reports Server (NTRS)

    Weber, Arthur L.

    2003-01-01

    The rates of thermal transformation of organic molecules containing carbon, hydrogen, and oxygen were systematically examined in order to identify the kinetic constraints that governed origin-of-life organic chemistry under mild aqueous conditions. Arrhenius plots of the kinetic data were used to estimate the reaction half-life at 50 C, and to reveal the effect of functional groups on reactivity. This survey showed that hydrocarbons and organic substances containing a single oxygenated group were kinetically the most stable (i. e. acetate decarboxylation half-life was l0(exp 18) years at 50 C); whereas, organic substances containing two oxygenated groups in which one group was a beta-positioned carbonyl group were the most reactive (i. e. acetoacetate decarboxylation half-life was l0(exp-2) years at 50 C). Of all functional groups the beta-positioned carbonyl group (aldehyde or ketone) was the strongest activating group, giving rates of reaction that were up to 10(exp 24)-times faster than rates of similar molecules lacking the beta-carbonyl group. From this knowledge of organic reactivity and the inherent constraints of autocatalytic processes, we concluded that an origins-of-life process based on autocatalytic transformation of C,H,O-substrates was constrained to using the most reactive organic molecules that contain alpha- or beta-carbonyl groups, since small autocatalytic domains of plausible catalytic power that used less reactive substrates could not carry out chemical transformations fast enough to prevent catastrophic efflux (escape) of reaction intermediates. Knowledge of the kinetics of organic transformations is useful, not only in constraining the chemistry of the earliest autocatalytic process related to the origin of life, but also in establishing the relative reactivity of organic molecules on the early Earth and other planets that may or may not be related to the origin of life.

  6. Chemical constraints governing the origin of metabolism: the thermodynamic landscape of carbon group transformations under mild aqueous conditions

    NASA Technical Reports Server (NTRS)

    Weber, Arthur L.

    2002-01-01

    The thermodynamics of organic chemistry under mild aqueous conditions was examined in order to begin to understand its influence on the structure and operation of metabolism and its antecedents. Free energies (deltaG) were estimated for four types of reactions of biochemical importance carbon-carbon bond cleavage and synthesis, hydrogen transfer between carbon groups, dehydration of alcohol groups, and aldo-keto isomerization. The energies were calculated for mainly aliphatic groups composed of carbon, hydrogen, and oxygen. The energy values showed (1) that generally when carbon-carbon bond cleavage involves groups from different functional group classes (i.e., carboxylic acids, carbonyl groups, alcohols, and hydrocarbons), the transfer of the shared electron-pair to the more reduced carbon group is energetically favored over transfer to the more oxidized carbon group, and (2) that the energy of carbon-carbon bond transformation is primarily determined by the functional group class of the group that changes oxidation state in the reaction (i.e., the functional group class of the group that donates the shared electron-pair during cleavage, or that accepts the incipient shared electron-pair during synthesis). In contrast, the energy of hydrogen transfer between carbon groups is determined by the functional group class of both the hydrogen-donor group and the hydrogen-acceptor group. From these and other observations we concluded that the chemistry involved in the origin of metabolism (and to a lesser degree modern metabolism) was strongly constrained by (1) the limited redox-based transformation energy of organic substrates that is readily dissipated in a few energetically favorable irreversible reactions; (2) the energy dominance of a few transformation half-reactions that determines whether carbon-carbon bond transformation (cleavage or synthesis) is energetically favorable (deltaG < -3.5 kcal/mol), reversible (deltaG between +/-3.5 kcal/mol), or unfavorable (delta

  7. Aqueous hydrodechlorination of 4-chlorophenol over an Rh/reduced graphene oxide synthesized by a facile one-pot solvothermal process under mild conditions.

    PubMed

    Ren, Yanlin; Fan, Guangyin; Wang, Chenyu

    2014-06-15

    Reduced graphene oxide (RGO) supported rhodium nanoparticles (Rh-NPs/RGO) was synthesized through one-pot polyol co-reduction of graphene oxide (GO) and rhodium chloride. The catalytic property of Rh-NPs/RGO was investigated for the aqueous phase hydrodechlorination (HDC) of 4-chlorophenol (4-CP). A complete conversion of 4-CP into high valued products of cyclohexanone (selectivity: 23.2%) and cyclohexanol (selectivity: 76.8%) was successfully achieved at 303K and balloon hydrogen pressure in a short reaction time of 50 min when 1.5 g/L of 4-CP was introduced. By comparing with Rh-NPs deposited on the other supports, Rh-NPs/RGO delivered the highest initial rate (111.4 mmol/gRh min) for 4-CP HDC reaction under the identical conditions. The substantial catalytic activity of Rh-NPs/RGO can be ascribed to the small and uniform particle size of Rh (average particle size was 1.7 ± 0.14 nm) on the surface of the RGO sheets and an electron-deficient state of Rh in the catalyst as a result of the strong interaction between the active sites and the surface function groups of RGO.

  8. Solvolytic liquefaction of wood under mild conditions

    SciTech Connect

    Yu, S.M.

    1982-04-01

    Conversion of wood to liquid products requires cleavage of bonds which crosslink the wood structure. This study examines a low-severity wood solubilization process utilizing a solvent medium consisting of a small amount of sulfuric acid and a potentially wood-derivable alcohol. In one half hour of reaction time at 250/sup 0/C under 15 psia starting nitrogen pressure, over 95% of the wood (maf) was rendered acetone-soluble. The product is a soft, black, bitumen-like solid at room temperature but readily softens at 140/sup 0/C. Between 25 and 50% of the original wood oxygen, depending on alcohol used, was removed as water. Approximately 2 to 17% of the alcohols were retained in the product. Gel permeation chromatography showed that the product's median molecular weight is around 300. Based on experimental and literature results, a mechanism for wood solubilization is proposed. This involves protonation of the etheric oxygen atoms, leading to subsequent bond scission to form carbonium ions which are stabilized by solvent alkoxylation. At severe conditions, polymerization and condensation reactions result in acetone-insoluble materials.

  9. SCANDIUM TRIFLATE CATALYZED ACETYLATION OF STARCH UNDER MILD CONDITIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Scandium (III) trifluoromethan sulfonate (Sc(OTf)3) was investigated as a catalyst for the acetylation of starch in order to determine the potential for preparing new types of starch esters under mild conditions. At room temperature, dry granular corn starch reacts with acetic anhydride in the pres...

  10. Dual Hypervalent Iodine(III) Reagents and Photoredox Catalysis Enable Decarboxylative Ynonylation under Mild Conditions.

    PubMed

    Huang, Hanchu; Zhang, Guojin; Chen, Yiyun

    2015-06-26

    A combination of hypervalent iodine(III) reagents (HIR) and photoredox catalysis with visible light has enabled chemoselective decarboxylative ynonylation to construct ynones, ynamides, and ynoates. This ynonylation occurs effectively under mild reaction conditions at room temperature and on substrates with various sensitive and reactive functional groups. The reaction represents the first HIR/photoredox dual catalysis to form acyl radicals from α-ketoacids, followed by an unprecedented acyl radical addition to HIR-bound alkynes. Its efficient construction of an mGlu5 receptor inhibitor under neutral aqueous conditions suggests future visible-light-induced biological applications.

  11. Chronoamperometric study of mild steel pitting in sodium sulfide aqueous solution

    SciTech Connect

    Otero, T.F.; Achucarro, C. . Dept. de Ciencia y Tecnologia de Polimeros)

    1994-08-01

    Mild steel samples were studied by chronoamperometry in sodium sulfide (Na[sub 2]S) aqueous solution. Pit nucleation and growth also were monitored by optical microscopy. The influence of variables such as temperature, polarization potential, surface roughness, the presence of electrochemically generated oxide layers, and the simultaneous presence of potassium hydroxide (KOH) was studied. The influence of each parameter on pit shape and growth was reviewed. Different reactions and competitive processes were proposed based on the experimental results.

  12. Ruthenium-Catalyzed Methylation of Amines with Paraformaldehyde in Water under Mild Conditions.

    PubMed

    van der Waals, Dominic; Heim, Leo E; Gedig, Christian; Herbrik, Fabian; Vallazza, Simona; Prechtl, Martin H G

    2016-09-01

    Methylated amines are highly important for a variety of pharmaceutical and agrochemical applications. Existing routes for their formation result in the production of large amounts of waste or require high reaction temperatures, both of which impact the ecological and economical footprint of the methodologies. Herein, we report the ruthenium-catalyzed reductive methylation of a range of aliphatic amines, using paraformaldehyde as both substrate and hydrogen source, in combination with water. This reaction proceeds under mild aqueous reaction conditions. Additionally the use of a secondary phase for catalyst retention and recycling has been investigated with promising results.

  13. Biomineralization of arsenate to arsenic sulfides is greatly enhanced at mildly acidic conditions.

    PubMed

    Rodriguez-Freire, Lucia; Sierra-Alvarez, Reyes; Root, Robert; Chorover, Jon; Field, James A

    2014-12-01

    Arsenic (As) is an important water contaminant due to its high toxicity and widespread occurrence. Arsenic-sulfide minerals (ASM) are formed during microbial reduction of arsenate (As(V)) and sulfate (SO4(2-)). The objective of this research is to study the effect of the pH on the removal of As due to the formation of ASM in an iron-poor system. A series of batch experiments was used to study the reduction of SO4(2-) and As(V) by an anaerobic biofilm mixed culture in a range of pH conditions (6.1-7.2), using ethanol as the electron donor. Total soluble concentrations and speciation of S and As were monitored. Solid phase speciation of arsenic was characterized by x-ray adsorption spectroscopy (XAS). A marked decrease of the total aqueous concentrations of As and S was observed in the inoculated treatments amended with ethanol, but not in the non-inoculated controls, indicating that the As-removal was biologically mediated. The pH dramatically affected the extent and rate of As removal, as well as the stoichiometric composition of the precipitate. The amount of As removed was 2-fold higher and the rate of the As removal was up to 17-fold greater at pH 6.1 than at pH 7.2. Stoichiometric analysis and XAS results confirmed the precipitate was composed of a mixture of orpiment and realgar, and the proportion of orpiment in the sample increased with increasing pH. The results taken as a whole suggest that ASM formation is greatly enhanced at mildly acidic pH conditions. PMID:25222328

  14. Biomineralization of arsenate to arsenic sulfides is greatly enhanced at mildly acidic conditions.

    PubMed

    Rodriguez-Freire, Lucia; Sierra-Alvarez, Reyes; Root, Robert; Chorover, Jon; Field, James A

    2014-12-01

    Arsenic (As) is an important water contaminant due to its high toxicity and widespread occurrence. Arsenic-sulfide minerals (ASM) are formed during microbial reduction of arsenate (As(V)) and sulfate (SO4(2-)). The objective of this research is to study the effect of the pH on the removal of As due to the formation of ASM in an iron-poor system. A series of batch experiments was used to study the reduction of SO4(2-) and As(V) by an anaerobic biofilm mixed culture in a range of pH conditions (6.1-7.2), using ethanol as the electron donor. Total soluble concentrations and speciation of S and As were monitored. Solid phase speciation of arsenic was characterized by x-ray adsorption spectroscopy (XAS). A marked decrease of the total aqueous concentrations of As and S was observed in the inoculated treatments amended with ethanol, but not in the non-inoculated controls, indicating that the As-removal was biologically mediated. The pH dramatically affected the extent and rate of As removal, as well as the stoichiometric composition of the precipitate. The amount of As removed was 2-fold higher and the rate of the As removal was up to 17-fold greater at pH 6.1 than at pH 7.2. Stoichiometric analysis and XAS results confirmed the precipitate was composed of a mixture of orpiment and realgar, and the proportion of orpiment in the sample increased with increasing pH. The results taken as a whole suggest that ASM formation is greatly enhanced at mildly acidic pH conditions.

  15. Biomineralization of Arsenate to Arsenic Sulfides is Greatly Enhanced at Mildly Acidic Conditions

    PubMed Central

    Rodriguez-Freire, Lucia; Sierra-Alvarez, Reyes; Root, Robert; Chorover, Jon; Field, James A.

    2014-01-01

    Arsenic (As) is an important water contaminant due to its high toxicity and widespread occurrence. Arsenic-sulfide minerals (ASM) are formed during microbial reduction of arsenate (AsV) and sulfate (SO42−). The objective of this research is to study the effect of the pH on the removal of As due to the formation of ASM in an iron-poor system. A series of batch experiments was used to study the reduction of SO42− and AsV by an anaerobic biofilm mixed culture in a range of pH conditions (6.1–7.2), using ethanol as the electron donor. Total soluble concentrations and speciation of S and As were monitored. Solid phase speciation of arsenic was characterized by x-ray adsorption spectroscopy (XAS). A marked decrease of the total aqueous concentrations of As and S was observed in the inoculated treatments amended with ethanol, but not in the non-inoculated controls, indicating that the As-removal was biologically mediated. The pH dramatically affected the extent and rate of As removal, as well as the stoichiometric composition of the precipitate. The amount of As removed was 2-fold higher and the rate of the As removal was up to 17-fold greater at pH 6.1 than at pH 7.2. Stoichiometric analysis and XAS results confirmed the precipitate was composed of a mixture of orpiment and realgar, and the proportion of orpiment in the sample increased with increasing pH. The results taken as a whole suggest that ASM formation is greatly enhanced at mildly acidic pH conditions. PMID:25222328

  16. Preparation and Characterization of Colloidal Silica Particles under Mild Conditions

    ERIC Educational Resources Information Center

    Neville, Frances; Zin, Azrinawati Mohd.; Jameson, Graeme J.; Wanless, Erica J.

    2012-01-01

    A microscale laboratory experiment for the preparation and characterization of silica particles at neutral pH and ambient temperature conditions is described. Students first employ experimental fabrication methods to make spherical submicrometer silica particles via the condensation of an alkoxysilane and polyethyleneimine, which act to catalyze…

  17. Processing of Primordial Organic Compounds in Carbonaceous Chondrites by mild Aqueous Alteration

    NASA Astrophysics Data System (ADS)

    Trigo-Rodriguez, J. M.; Martins, Z.; Rimola, A.

    2016-08-01

    New evidence suggests a synthesis of complex organic species in water-rich undifferentiated bodies. Quantum mechanical methods are compared with experimental data to see if organic matter was processed by clay formation during aqueous alteration.

  18. Mild Palladium-Catalyzed Cyanation of (Hetero)aryl Halides and Triflates in Aqueous Media

    PubMed Central

    2016-01-01

    A mild, efficient, and low-temperature palladium-catalyzed cyanation of (hetero)aryl halides and triflates is reported. Previous palladium-catalyzed cyanations of (hetero)aryl halides have required higher temperatures to achieve good catalytic activity. This current reaction allows the cyanation of a general scope of (hetero)aryl halides and triflates at 2–5 mol % catalyst loadings with temperatures ranging from rt to 40 °C. This mild method was applied to the synthesis of lersivirine, a reverse transcriptase inhibitor. PMID:25555140

  19. The Formation of Fe/Mg Smectite Under Mildly Acidic Conditions on Early Mars

    NASA Technical Reports Server (NTRS)

    Sutter, B.; Golden, D. C.; Ming, Douglas W.; Niles, P. B.

    2011-01-01

    The detection of Fe/Mg smectites and carbonate in Noachian and early Hesperian terrain of Mars suggests that neutral to mildly alkaline conditions prevailed during the early history of Mars. If early Mars surface geochemical conditions were neutral to moderately alkaline with a denser CO2 atmosphere than today, then large carbonates deposits should be more widely detected in Noachian terrain. Why have so few carbonate deposits been detected compared to Fe/Mg smectites? Fe/Mg smectites on early Mars formed under mildly acidic conditions, which would preclude the extensive formation of carbonate deposits. The goal of the proposed work is to evaluate the formation of Fe/Mg smectites under mildly acidic conditions.

  20. Timescales and conditions for the aqueous alteration of chondrites

    NASA Astrophysics Data System (ADS)

    Jilly, Christine E.

    It has become well-recognized that water played a critical role in the early geological evolution of materials through observation of hydrated phases in chondritic meteorites. However, details about the mechanism, timing, and conditions of aqueous alteration are poorly constrained. This dissertation investigates water-driven processes in Renazzo-like (CR) carbonaceous chondrites, with some comparison to the heavily altered and Mighei-like (CM) chondrites. CR chondrites were chosen as the focus of this study, as they are the only chondrite group to range from practically anhydrous to completely hydrated, providing petrographic context for the aqueous alteration process. The central goal of the thesis is to elucidate the complete mechanism of aqueous alteration, from primary anhydrous components to secondary minerals. This research uses a variety of micro-analytical techniques to address three main objectives: 1) to detail the petrographic context, 2) to quantify the onset and duration of alteration using radiometric dating, and 3) to constrain the fluid chemistry and conditions for aqueous alteration. On a microscopic scale, fine-grained matrices and glassy mesostases were the first phases to become altered, allowing for elemental transport over short distances (< 100 microns). As alteration progressed, the iron-metal was oxidized, and silicate phenocrysts were pseudomorphically replaced. 53Mn-53 Cr radiometric dating of secondary carbonates in CR chondrites show that aqueous alteration began quickly after accretion of the parent body, ~4 Myr after the beginning of the Solar System. This is contemporaneous with dolomite formation in the CM chondrite Sutter's Mill and with carbonate formation in other CM chondrites. However, the calcite age from a heavily hydrated CR lithology indicates that late-stage alteration occurred ~12 Myr after the beginning of the Solar System. The oxygen isotopic compositions of magnetite and carbonate minerals reveal that altering fluid

  1. Metal-Free Markovnikov-Type Alkyne Hydration under Mild Conditions.

    PubMed

    Liu, Wenbo; Wang, Haining; Li, Chao-Jun

    2016-05-01

    A Markovnikov-type alkyne hydration protocol is presented using 20% CF3SO3H (TfOH) as the catalyst under unprecedented mild conditions applicable to various alkynes, including terminal arylalkynes, terminal nonfunctionalized aliphatic alkynes, and internal alkynes with excellent regioselectivity in good to excellent yields (average yields >85%). The reaction procedure operates under mild conditions (25-70 °C), with broad functional group compatibility, and uses only slightly more than a stoichiometric amount of water in the absence of any transition metal. The success of this protocol hinges upon the utilization of trifluoroethanol as the solvent. PMID:27082159

  2. Facile synthesis of nano-sized hollow single crystal zeolites under mild conditions.

    PubMed

    Fodor, Daniel; Pacosová, Lucie; Krumeich, Frank; van Bokhoven, Jeroen A

    2014-01-01

    We report a method to synthesize hollow ZSM-5 single crystals of a size below 100 nm that could function as nanoreactors with access through the zeolite micropores only. In the first step, ZSM-5 is synthesized with the respective crystal size. In the second, the zeolite is base leached and acid washed under mild conditions.

  3. A mild, near-surface aqueous environment on Noachian Mars preserved in ALH84001

    NASA Astrophysics Data System (ADS)

    Halevy, I.; Fischer, W. W.; Eiler, J. M.

    2011-12-01

    Despite widespread evidence for liquid water at the surface of Mars during parts of the Noachian epoch, the temperature of early aqueous environments has been impossible to establish, raising questions of whether Mars' surface was ever warmer than today. This has hindered insight into aqueous alteration processes, which, on the basis of orbital spectroscopy, appear to have been prevalent on Noachian Mars. It is important to understand such processes, as they link the observed secondary mineral assemblages to interactions between primary igneous silicates and the surface environment (atmosphere-hydrosphere). We have addressed this problem by determining the precipitation temperatures of secondary carbonate minerals preserved in the oldest known sample of Mars' crust-the meteorite Allan Hills 84001 (ALH84001). Using carbonate 'clumped' isotope thermometry we have found that the carbonates in ALH84001, which are 3.9-4.0 billion years old, formed at a temperature of ~18±4°C. With temperature known, we used the carbon and oxygen isotopic composition of the carbonates, as constrained by both our measurements and previous acid digestion and ion microprobe studies, to develop a model for their formation process and environment. The observed isotopic variation is best explained by carbonate precipitation out of a gradually evaporating, shallow subsurface aqueous solution (e.g. a regolith aquifer) at near-constant temperatures. Furthermore, on the basis of the isotopic composition of the earliest precipitated carbonates in ALH84001, the volatiles from which they formed (H2O and CO2) came not from depth, but from the early Martian surface. The occurrence of carbonates in other SNC meteorites and as a minor component of Martian dust implies that environments analogous to the one we studied may have been important in generating some of the observed secondary mineral assemblages by interaction between Mars' igneous crust and its atmosphere-hydrosphere.

  4. Attenuation of aqueous benzene in soils under saturated flow conditions.

    PubMed

    Kim, S-B; Kim, D-J; Yun, S-T

    2006-01-01

    The fate of aqueous benzene in subsurface was investigated in this study, focusing on the role of sorption and biodegradation on the benzene attenuation under dynamic flow conditions. Two sets of column tests were conducted in Plexiglass flow cells packed uniformly with sandy aquifer materials. The first set of the experiment was conducted with a step-type injection of benzene with different powder activated carbon (PAC) contents: (1) PAC = 0 %; (2) PAC = 0.5 %; (3) PAC = 2.0%. The second set was performed as a pulse-type with different test conditions: (4) benzene; (5) benzene and bacteria (Pseudomonas aeruginosa); (6) benzene and bacteria (P. aeruginosa) with hydrogen peroxide. In addition, numerical experiments were performed to examine the role of sorption processes on the benzene attenuation. In the step mode experiments, the KCl breakthrough curves (BTCs) reached the input concentration while the benzene BTCs were considerably lower than those of KCl with slight retardation for all cases, indicating that both reversible/retardation and irreversible sorption occurred. The pulse type tests showed that attenuation of benzene increased in the presence of bacteria due to biodegradation. The benzene attenuation by microbial degradation increased furthermore in the presence of hydrogen peroxide owing to sufficient supply of dissolved oxygen in soil column. Numerical experiments demonstrated that retardation could not contribute to the attenuation of benzene in soils but could only extend its breakthrough time. Experimental results indicated that aqueous benzene could be attenuated by irreversible sorption and biodegradation during transport through the subsurface. Additionally, the attenuation of aqueous benzene is closely related to organic carbon content and oxygen level existing in contaminated aquifers.

  5. The Formation of Fe/Mg Smectite Under Mildly Acidic Conditions on Early Mars

    NASA Technical Reports Server (NTRS)

    Sutter, Brad; Golden, D. C.; Ming, Douglas W.; Niles, P. B.

    2011-01-01

    The detection of Fe/Mg smectites and carbonate in Noachian and early Hesperian terrain of Mars has been used to suggest that neutral to mildly alkaline conditions prevailed during the early history of Mars. However, if early Mars was neutral to moderately alkaline with a denser CO2 atmosphere than today, then large carbonates deposits should be more widely detected in Noachian terrain. The critical question is: Why have so few carbonate deposits been detected compared to Fe/Mg smectites? We suggest that Fe/Mg smectites on early Mars formed under mildly acidic conditions, which would inhibit the extensive formation of carbonate deposits. The goal of this work is to evaluate the formation of Fe/Mg smectites under mildly acidic conditions. The stability of smectites under mildly acidic conditions is attributed to elevated Fe/Mg activities that inhibit smectite dissolution. Beidelite and saponite have been shown to form from hydrothermal alteration of basaltic glass at pH 3.5-4.0 in seawater solutions. Nontronite is also known to be stable in mildly acidic systems associated with mafic and ultramafic rock. Nontronite was shown to form in acid sulfate soils in the Bangkok Plain, Thailand due to oxidation of Fe-sulfides that transformed saponite to nontronite. Smectite is known to transform to kaolinite in naturally acid soils due to selective leaching of Mg. However, if Mg removal is limited, then based on equilibrium relationships, the dissolution of smectite should be minimized. If Fe and Mg solution activities are sufficiently high, such as might be found in a low water/rock ratio system that is poorly drained, smectite could form and remain stable under mildly acidic conditions on Mars. The sources of mild acidity on early Mars includes elevated atmospheric CO2 levels, Fe-hydrolysis reactions, and the presence of volcanic SO2 aerosols. Equilibrium calculations dictate that water equilibrated with an early Mars CO2 atmosphere at 1 to 4 bar yields a pH of 3.6 to 3

  6. The Formation of Fe/Mg Smectite Under Mildly Acidic Conditions on Early Mars

    NASA Astrophysics Data System (ADS)

    Sutter, B.; Golden, D. C.; Ming, D.; Niles, P. B.

    2011-12-01

    The detection of Fe/Mg smectites and carbonate in Noachian and early Hesperian terrain of Mars has been used to suggest that neutral to mildly alkaline conditions prevailed during the early history of Mars. However, if early Mars was neutral to moderately alkaline with a denser CO2 atmosphere than today, then "large" carbonates deposits should be more widely detected in Noachian terrain. The critical question is: Why have so few carbonate deposits been detected compared to Fe/Mg smectites? We suggest that Fe/Mg smectites on early Mars formed under mildly acidic conditions, which would inhibit the extensive formation of carbonate deposits. The goal of this work is to evaluate the formation of Fe/Mg smectites under mildly acidic conditions. The stability of smectites under mildly acidic conditions is attributed to elevated Fe/Mg activities that inhibit smectite dissolution. Beidelite and saponite have been shown to form from hydrothermal alteration of basaltic glass at pH 3.5-4.0 in seawater solutions. Nontronite is also known to be stable in mildly acidic systems associated with mafic and ultramafic rock. Nontronite was shown to form in acid sulfate soils in the Bangkok Plain, Thailand due to oxidation of Fe-sulfides that transformed saponite to nontronite. Smectite is known to transform to kaolinite in naturally acid soils due to selective leaching of Mg. However, if Mg removal is limited, then based on equilibrium relationships, the dissolution of smectite should be minimized. If Fe and Mg solution activities are sufficiently high, such as might be found in a low water/rock ratio system that is poorly drained, smectite could form and remain stable under mildly acidic conditions on Mars. The sources of mild acidity on early Mars includes elevated atmospheric CO2 levels, Fe-hydrolysis reactions, and the presence of volcanic SO2 aerosols. Equilibrium calculations dictate that water equilibrated with an early Mars CO2 atmosphere at 1 to 4 bar yields a pH of 3.6 to 3

  7. Effects of surface condition on aqueous corrosion and environmental embrittlement of iron aluminides

    SciTech Connect

    Perrin, R.L.; Buchanan, R.A.

    1996-08-01

    Effects of retained high-temperature surface oxides, produced during thermomechanical processing and/or heat treatment, on the aqueous-corrosion and environmental-embrittlement characteristics of Fe{sub 3}Al-based iron aluminides (FA-84, FA-129 and FAL-Mo), a FeAl-based iron aluminide (FA-385), and a disordered low-aluminum Fe-Al alloy (FAPY) were evaluated. All tests were conducted at room temperature in a mild acid-chloride solution. In cyclic-anodic-polarization testing for aqueous-corrosion behavior, the surface conditions examined were: as-received (i.e., with the retained high-temperature oxides), mechanically cleaned and chemically cleaned. For all materials, the polarization tests showed the critical pitting potentials to be significantly lower in the as-received condition than in the mechanically-cleaned and chemically-cleaned conditions. These results indicate detrimental effects of the retained high-temperature oxides in terms of increased susceptibilities to localized corrosion. In 200-hour U-bend stress-corrosion-cracking tests for environmental-embrittlement behavior, conducted at open-circuit corrosion potentials and at a hydrogen-charging potential of {minus}1500 mV (SHE), the above materials (except FA-385) were examined with retained oxides and with mechanically cleaned surfaces. At the open-circuit corrosion potentials, none of the materials in either surface condition underwent cracking. At the hydrogen-charging potential, none of the materials with retained oxides underwent cracking, but FA-84, FA-129 and FAL-Mo in the mechanically cleaned condition did undergo cracking. These results suggest beneficial effects of the retained high-temperature oxides in terms of increased resistance to environmental hydrogen embrittlement.

  8. Nitrous oxide activation by a cobalt(ii) complex for aldehyde oxidation under mild conditions.

    PubMed

    Corona, Teresa; Company, Anna

    2016-10-01

    Nitrous oxide (N2O) is a waste gas produced in many industrial processes with an important environmental impact. Thus, its application as an oxidant is highly desirable because it produces innocuous N2 as a by-product. In this work we report a new cobalt(ii) complex that reacts with N2O under mild conditions and the catalytic application of this system to carry out the oxidation of aldehydes. PMID:27445004

  9. Nitrous oxide activation by a cobalt(ii) complex for aldehyde oxidation under mild conditions.

    PubMed

    Corona, Teresa; Company, Anna

    2016-10-01

    Nitrous oxide (N2O) is a waste gas produced in many industrial processes with an important environmental impact. Thus, its application as an oxidant is highly desirable because it produces innocuous N2 as a by-product. In this work we report a new cobalt(ii) complex that reacts with N2O under mild conditions and the catalytic application of this system to carry out the oxidation of aldehydes.

  10. Instability of Amide Bond Comprising the 2-Aminotropone Moiety: Cleavable under Mild Acidic Conditions.

    PubMed

    Balachandra, Chenikkayala; Sharma, Nagendra K

    2015-08-21

    An unusual hydrolysis/solvolysis of the classical acyclic amide bond, derived from N-troponylaminoethylglycine (Traeg) and α-amino acids, is described under mild acidic conditions. The reactivity of this amide bond is possibly owed to the protonation of the troponyl carbonyl functional group. The results suggest that the Traeg amino acid is a potential candidate for protecting and caging of the amine functional group of bioactive molecules via a cleavable amide bond.

  11. CoCl(PPh3)3 as Cyclotrimerization Catalyst for Functionalized Triynes under Mild Conditions.

    PubMed

    Jungk, Phillip; Fischer, Fabian; Thiel, Indre; Hapke, Marko

    2015-10-01

    The ubiquitary Co(I) complex CoCl(PPh3)3 was found to be a convenient catalyst for the [2 + 2 + 2] cycloaddition of functionalized triynes under mild reaction conditions and devoid of any additional additive, yielding the substituted arene compounds. Successful development of synthetic routes to various triynes and the subsequent cyclotrimerization key step gave systematic access to a variety of different bi- and triaryls with good to excellent yields for the cyclization.

  12. Dehydrogenative N-incorporation: a direct approach to quinoxaline N-oxides under mild conditions.

    PubMed

    Chen, Feng; Huang, Xiaoqiang; Li, Xinyao; Shen, Tao; Zou, Miancheng; Jiao, Ning

    2014-09-22

    An efficient method for the synthesis of quinoxaline N-oxides proceeds by the dehydrogenative N-incorporation of simple imines by C(sp(2))-H and C(sp(3))-H bond functionalization. The overall transformation involves the cleavage of three C-H bonds. The reaction is easily handled and proceeds under mild conditions. Simple and readily available tert-butyl nitrite (TBN) was employed as the NO source.

  13. Thermal signature of fear conditioning in mild post traumatic stress disorder.

    PubMed

    Di Giacinto, A; Brunetti, M; Sepede, G; Ferretti, A; Merla, A

    2014-04-25

    Fear conditioning has been proposed as an important factor involved in the etiology of posttraumatic stress disorder (PTSD). We examined fear processing in PTSD patients with mild symptoms and in individuals who did not develop symptoms (both groups consisting of victims of a bank robbery), through the study of fear-conditioned response. Conditioned responses were quantified by the skin conductance response (SCR) and the facial thermal response, the latter being measured by high-resolution functional thermal infrared (fIR) imaging. We found: (a) a change of the physiological parameters with respect to the baseline condition in both control subjects and PTSD patients during the conditioning phase; (b) the permanence of the conditioning effect in the maintenance phase in both control and PTSD patients; (c) patients and controls did differ for the variation across the phases of the physiological parameters rather than for their absolute values, showing that PTSD patients had a prolonged excitation and higher tonic component of autonomic activity. These results, although preliminary, indicate that the analysis of SCR and facial thermal response during the conditioning paradigm is a promising psychometric method of investigation, even in the case of low level of PTSD symptom severity. To the best of our knowledge, this study is the first attempt to discriminate between control subjects and PTSD patients with mild symptoms through infrared thermal imaging. It may suggest feasible approaches for diagnostic screening in the early phases of the disorder and in the assessment of preventive measures and therapies. PMID:24561216

  14. Strongly adherent polypyrrole coatings obtained by electropolymerization of pyrrole on oxidizable metals in aqueous electrolytic media. I. Iron and mild steel

    NASA Astrophysics Data System (ADS)

    Ferreira, C. A.; Aeiyach, S.; Aaron, J. J.; Lacaze, P. C.

    1996-01-01

    Strongly adherent polypyrrole (PPy) films have been obtained by electropolymerization of pyrrole on HNO3 pretreated iron and mild steel in various aqueous media containing Na2SO4, K2C2O4 or KNO3. The quality of the PPy coatings was improved by adding to the pyrroles solutions small amounts of pyrroles with -COOH and -NH2 groups at the 2-position, followed by heat treatment of the PPy films, leading to polycondensation of the chains. After cataphoresis, the resistance of this new coating to salt spray tests was as good as that of the usual cataphoretic coatings obtained on phosphated mild steels.

  15. Heat-moisture treatment under mildly acidic conditions alters potato starch physicochemical properties and digestibility.

    PubMed

    Kim, Jong-Yea; Huber, Kerry C

    2013-11-01

    Potato starch was subjected to heat-moisture treatment (HMT; 120 °C, 3 h) under mildly acidic conditions (pH 5, 6, or 6.5 [control]) at moisture levels of 15, 20 or 25%. HMT starches exhibited significantly delayed pasting times and reduced overall paste viscosities, amylose leaching, and granular swelling characteristics relative to native starch, as well as enhanced levels of thermo-stable resistant starch (≈24%). HMT appeared to alter/enhance short-range chain associations (FT-IR) within amorphous and/or crystalline regions of starch granules. However, the extent of physicochemical change and RS enhancement during HMT was most facilitated by a mildly acidic condition (pH 6) at higher treatment moisture levels (20 or 25%). These conditions promoted limited hydrolysis of amylopectin molecules, primarily at α-(1→6) branch points, likely enhancing mobility and interaction of starch chains during HMT. Thus, a slightly acidic pH might reduce conditions and/or timeframe needed to impart physicochemical changes and reduced digestibility to potato starch. PMID:24053800

  16. Differential Response in Downstream Processing of CHO Cells Grown Under Mild Hypothermic Conditions

    PubMed Central

    Tait, Andrew S; Tarrant, Richard D R; Velez-Suberbie, M Lourdes; Spencer, Daniel I R; Bracewell, Daniel G

    2013-01-01

    The manufacture of complex therapeutic proteins using mammalian cells is well established, with several strategies developed to improve productivity. The application of sustained mild hypothermic conditions during culture has been associated with increases in product titer and improved product quality. However, despite associated cell physiological effects, very few studies have investigated the impact on downstream processing (DSP). Characterization of cells grown under mild hypothermic conditions demonstrated that the stationary phase was prolonged by delaying the onset of apoptosis. This enabled cells to maintain viability for extended periods and increase volumetric productivity from 0.74 to 1.02 g L−1. However, host cell proteins, measured by ELISA, increased by ∼50%, attributed to the extended time course and higher peak and harvest cell densities. The individual components making up this impurity, as determined by SELDI-TOF MS and 2D-PAGE, were shown to be largely comparable. Under mild hypothermic conditions, cells were less shear sensitive than those maintained at 37°C, enhancing the preliminary primary recovery step. Adaptive changes in membrane fluidity were further investigated by adopting a pronounced temperature shift immediately prior to primary recovery and the improvement observed suggests that such a strategy may be implementable when shear sensitivity is of concern. Early and late apoptotic cells were particularly susceptible to shear, at either temperature, even under the lowest shear rate investigated. These findings demonstrate the importance of considering the impact of cell culture strategies and cell physiology on DSP, by implementing a range of experimental methods for process characterization. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:688–696, 2013 PMID:23636936

  17. Efficient chemisorption of organophosphorous redox probes on indium tin oxide surfaces under mild conditions.

    PubMed

    Forget, Amélie; Limoges, Benoît; Balland, Véronique

    2015-02-17

    We report a mild and straightforward one-step chemical surface functionalization of indium tin oxide (ITO) electrodes by redox-active molecules bearing an organophosphoryl anchoring group (i.e., alkyl phosphate or alkyl phosphonate group). The method takes advantage of simple passive adsorption in an aqueous solution at room temperature. We show that organophosphorus compounds can adsorb much more strongly and stably on an ITO surface than analogous redox-active molecules bearing a carboxylate or a boronate moiety. We provide evidence, through quantitative electrochemical characterization (i.e., by cyclic voltammetry) of the adsorbed organophosphoryl redox-active molecules, of the occurrence of three different adsorbate fractions on ITO, exhibiting different stabilities on the surface. Among these three fractions, one is observed to be strongly chemisorbed, exhibiting high stability and resistance to desorption/hydrolysis in a free-redox probe aqueous buffer. We attribute this remarkable stability to the formation of chemical bonds between the organophosphorus anchoring group and the metal oxide surface, likely occurring through a heterocondensation reaction in water. From XPS analysis, we also demonstrate that the surface coverage of the chemisorbed molecules is highly affected by the degree of surface hydroxylation, a parameter that can be tuned by simply preconditioning the freshly cleaned ITO surfaces in water. The lower the relative surface hydroxide density on ITO, the higher was the surface coverage of the chemisorbed species. This behavior is in line with a chemisorption mechanism involving coordination of a deprotonated phosphoryl oxygen atom to the non-hydroxylated acidic metal sites of ITO.

  18. Production of Retrovirus-Based Vectors in Mildly Acidic pH Conditions.

    PubMed

    Holic, Nathalie; Fenard, David

    2016-01-01

    Gene transfer vectors based on retroviridae are increasingly becoming a tool of choice for biomedical research and for the development of biotherapies in rare diseases or cancers. To meet the challenges of preclinical and clinical production, different steps of the production process of self-inactivating γ-retroviral (RVs) and lentiviral vectors (LVs) have been improved (e.g., transfection, media optimization, cell culture conditions). However, the increasing need for mass production of such vectors is still a challenge and could hamper their availability for therapeutic use. Recently, we observed that the use of a neutral pH during vector production is not optimal. The use of mildly acidic pH conditions (pH 6) can increase by two- to threefold the production of RVs and LVs pseudotyped with the vesicular stomatitis virus G (VSV-G) or gibbon ape leukemia virus (GALV) glycoproteins. Here, we describe the production protocol in mildly acidic pH conditions of GALVTR- and VSV-G-pseudotyped LVs using the transient transfection of HEK293T cells and the production protocol of GALV-pseudotyped RVs produced from a murine producer cell line. These protocols should help to achieve higher titers of vectors, thereby facilitating experimental research and therapeutic applications. PMID:27317171

  19. MICROWAVE-ASSISTED PREPARATION OF 1-BUTYL-3-METHYLIMIDAZOLIUM TETRACHLOROGALLATE AND ITS CATALYTIC USE IN ACETAL FORMATION UNDER MILD CONDITIONS

    EPA Science Inventory

    1-Butyl-3-methylimidazolium tetrachlorogallate, [bmim][GaCl4], prepared via microwave-assisted protocol, is found to be an active catalyst for the efficient acetalization of aldehydes under mild conditions.

  20. Mass spectrometric characterization of limited proteolysis activity in human plasma samples under mild acidic conditions.

    PubMed

    Yang, Jingzhi; Röwer, Claudia; Koy, Cornelia; Ruß, Manuela; Rüger, Christopher P; Zimmermann, Ralf; von Fritschen, Uwe; Bredell, Marius; Finke, Juliane C; Glocker, Michael O

    2015-11-01

    We developed a limited proteolysis assay for estimating dynamics in plasma-borne protease activities using MALDI ToF MS analysis as readout. A highly specific limited proteolysis activity was elicited in human plasma by shifting the pH to 6. Mass spectrometry showed that two singly charged ion signals at m/z 2753.44 and m/z 2937.56 significantly increased in abundance under mild acidic conditions as a function of incubation time. For proving that a provoked proteolytic activity in mild acidic solution caused the appearance of the observed peptides, control measurements were performed (i) with pepstatin as protease inhibitor, (ii) with heat-denatured samples, (iii) at pH 1.7, and (iv) at pH 7.5. Mass spectrometric fragmentation analysis showed that the observed peptides encompass the amino acid sequences 1-24 and 1-26 from the N-terminus of human serum albumin. Investigations on peptidase specificities suggest that the two best candidates for the observed serum albumin cleavages are cathepsin D and E. Reproducibility, robustness, and sensitivity prove the potential of the developed limited proteolysis assay to become of clinical importance for estimating dynamics of plasma-borne proteases with respect to associated pathophysiological tissue conditions.

  1. Degradation of textile dyes using immobilized lignin peroxidase-like metalloporphines under mild experimental conditions

    PubMed Central

    2012-01-01

    Background Synthetic dyes represent a broad and heterogeneous class of durable pollutants, that are released in large amounts by the textile industry. The ability of two immobilized metalloporphines (structurally emulating the ligninolytic peroxidases) to bleach six chosen dyes (alizarin red S, phenosafranine, xylenol orange, methylene blue, methyl green, and methyl orange) was compared to enzymatic catalysts. To achieve a green and sustainable process, very mild conditions were chosen. Results IPS/MnTSPP was the most promising biomimetic catalyst as it was able to effectively and quickly bleach all tested dyes. Biomimetic catalysis was fully characterized: maximum activity was centered at neutral pH, in the absence of any organic solvent, using hydrogen peroxide as the oxidant. The immobilized metalloporphine kept a large part of its activity during multi-cycle use; however, well-known redox mediators were not able to increase its catalytic activity. IPS/MnTSPP was also more promising for use in industrial applications than its enzymatic counterparts (lignin peroxidase, laccase, manganese peroxidase, and horseradish peroxidase). Conclusions On the whole, the conditions were very mild (standard pressure, room temperature and neutral pH, using no organic solvents, and the most environmental-friendly oxidant) and a significant bleaching and partial mineralization of the dyes was achieved in approximately 1 h. Therefore, the process was consistent with large-scale applications. The biomimetic catalyst also had more promising features than the enzymatic catalysts. PMID:23256784

  2. Pretreatment combining ultrasound and sodium percarbonate under mild conditions for efficient degradation of corn stover.

    PubMed

    Nakashima, Kazunori; Ebi, Yuuki; Kubo, Masaki; Shibasaki-Kitakawa, Naomi; Yonemoto, Toshikuni

    2016-03-01

    Ultrasound (US) can be used to disrupt microcrystalline cellulose to give nanofibers via ultrasonic cavitation. Sodium percarbonate (SP), consisting of sodium carbonate and hydrogen peroxide, generates highly reactive radicals, which cause oxidative delignification. Here, we describe a novel pretreatment technique using a combination of US and SP (US-SP) for the efficient saccharification of cellulose and hemicellulose in lignocellulosic corn stover. Although US-SP pretreatment was conducted under mild condition (i.e., at room temperature and atmospheric pressure), the pretreatment greatly increased lignin removal and cellulose digestibility. We also determined the optimum US-SP treatment conditions, such as ultrasonic power output, pretreatment time, pretreatment temperature, and SP concentration for an efficient cellulose saccharification. Moreover, xylose could be effectively recovered from US-SP pretreated biomass without the formation of microbial inhibitor furfural. PMID:26547502

  3. Pretreatment combining ultrasound and sodium percarbonate under mild conditions for efficient degradation of corn stover.

    PubMed

    Nakashima, Kazunori; Ebi, Yuuki; Kubo, Masaki; Shibasaki-Kitakawa, Naomi; Yonemoto, Toshikuni

    2016-03-01

    Ultrasound (US) can be used to disrupt microcrystalline cellulose to give nanofibers via ultrasonic cavitation. Sodium percarbonate (SP), consisting of sodium carbonate and hydrogen peroxide, generates highly reactive radicals, which cause oxidative delignification. Here, we describe a novel pretreatment technique using a combination of US and SP (US-SP) for the efficient saccharification of cellulose and hemicellulose in lignocellulosic corn stover. Although US-SP pretreatment was conducted under mild condition (i.e., at room temperature and atmospheric pressure), the pretreatment greatly increased lignin removal and cellulose digestibility. We also determined the optimum US-SP treatment conditions, such as ultrasonic power output, pretreatment time, pretreatment temperature, and SP concentration for an efficient cellulose saccharification. Moreover, xylose could be effectively recovered from US-SP pretreated biomass without the formation of microbial inhibitor furfural.

  4. On-resin N-terminal peptoid degradation: Toward mild sequencing conditions.

    PubMed

    Proulx, Caroline; Noë, Falko; Yoo, Stan; Connolly, Michael D; Zuckermann, Ronald N

    2016-09-01

    A novel approach to sequentially degrade peptoid N-terminal N-(substituted)glycine residues on the solid-phase using very mild conditions is reported. This method relies on the treatment of resin-bound, bromoacetylated peptoids with silver perchlorate in THF, leading to an intramolecular cyclization reaction to liberate the terminal residue as a N-substituted morpholine-2,5-dione, resulting in a truncated peptoid upon hydrolysis and a silver bromide byproduct. Side-chain functional group tolerance is explored and reaction kinetics are determined. In a series of pentapeptoids possessing variable, non-nucleophilic side-chains at the second position (R(2) ), we demonstrate that sequential N-terminal degradation of the first two residues proceeds in 87% and 74% conversions on average, respectively. We further demonstrate that the degradation reaction is selective for peptoids, and represents substantial progress toward a mild, iterative sequencing method for peptoid oligomers. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 726-736, 2016. PMID:27258140

  5. Efficient and selective degradation of polyethylenes into liquid fuels and waxes under mild conditions

    PubMed Central

    Jia, Xiangqing; Qin, Chuan; Friedberger, Tobias; Guan, Zhibin; Huang, Zheng

    2016-01-01

    Polyethylene (PE) is the largest-volume synthetic polymer, and its chemical inertness makes its degradation by low-energy processes a challenging problem. We report a tandem catalytic cross alkane metathesis method for highly efficient degradation of polyethylenes under mild conditions. With the use of widely available, low-value, short alkanes (for example, petroleum ethers) as cross metathesis partners, different types of polyethylenes with various molecular weights undergo complete conversion into useful liquid fuels and waxes. This method shows excellent selectivity for linear alkane formation, and the degradation product distribution (liquid fuels versus waxes) can be controlled by the catalyst structure and reaction time. In addition, the catalysts are compatible with various polyolefin additives; therefore, common plastic wastes, such as postconsumer polyethylene bottles, bags, and films could be converted into valuable chemical feedstocks without any pretreatment. PMID:27386559

  6. Degradation of chemical substances using wet peroxide oxidation under mild conditions.

    PubMed

    Okawa, Kiyokazu; Suzuki, Kazuyoshi; Takeshita, Toshihiro; Nakano, Katsuyuki

    2005-12-01

    The objectives of this study are to clarify the degradation mechanism of chemical substances using wet peroxide oxidation (WPO) under mild condition (150 degrees C) and to confirm the removal of polychlorinated biphenyls (PCBs) in soil using this oxidation process. Acetic and oxalic acids were mineralized using WPO. TOC removal rate of acetic acid was highest in the solution of pH 2.5. However, TOC removal rate was decreased with the increase in pH and TOC were hardly removed in the solution of pH 7 and 10. The decomposition rate of isobutyric acid by WPO decreased in the presence of radical scavenger (t-BuOH). The results suggested that the decomposition of chemical substances using WPO proceeded by hydroxyl radical (OH radical). PCBs in soil were also decomposed by performing WPO at 150 degrees C. PMID:16081206

  7. Promising gaseous and electrochemical hydrogen storage properties of porous Mg-Pd films under mild conditions.

    PubMed

    Xin, Gongbiao; Yuan, Huiping; Jiang, Lijun; Wang, Shumao; Liu, Xiaopeng; Li, Xingguo

    2015-05-28

    In this paper, the gaseous and electrochemical hydrogen storage properties of 200 nm Mg-Pd thin films with different morphologies have been investigated. The results show that Mg-Pd films become porous with the increase of substrate temperature. Porous Mg-Pd films exhibit superior gaseous and electrochemical hydrogen storage behaviors under mild conditions, including rapid hydrogen sorption kinetics, a large hydrogen storage amount, high electrochemical discharge capacity, and a fast hydrogen diffusion rate. The excellent behaviors of porous Mg-Pd films might be ascribed to the significantly shortened hydrogen diffusion paths and the large contact areas between the hydrogen gas and the solid Mg phases, which are elucidative for the development and applications of thick Mg-Pd films.

  8. Efficient and selective degradation of polyethylenes into liquid fuels and waxes under mild conditions.

    PubMed

    Jia, Xiangqing; Qin, Chuan; Friedberger, Tobias; Guan, Zhibin; Huang, Zheng

    2016-06-01

    Polyethylene (PE) is the largest-volume synthetic polymer, and its chemical inertness makes its degradation by low-energy processes a challenging problem. We report a tandem catalytic cross alkane metathesis method for highly efficient degradation of polyethylenes under mild conditions. With the use of widely available, low-value, short alkanes (for example, petroleum ethers) as cross metathesis partners, different types of polyethylenes with various molecular weights undergo complete conversion into useful liquid fuels and waxes. This method shows excellent selectivity for linear alkane formation, and the degradation product distribution (liquid fuels versus waxes) can be controlled by the catalyst structure and reaction time. In addition, the catalysts are compatible with various polyolefin additives; therefore, common plastic wastes, such as postconsumer polyethylene bottles, bags, and films could be converted into valuable chemical feedstocks without any pretreatment.

  9. Efficient and selective degradation of polyethylenes into liquid fuels and waxes under mild conditions.

    PubMed

    Jia, Xiangqing; Qin, Chuan; Friedberger, Tobias; Guan, Zhibin; Huang, Zheng

    2016-06-01

    Polyethylene (PE) is the largest-volume synthetic polymer, and its chemical inertness makes its degradation by low-energy processes a challenging problem. We report a tandem catalytic cross alkane metathesis method for highly efficient degradation of polyethylenes under mild conditions. With the use of widely available, low-value, short alkanes (for example, petroleum ethers) as cross metathesis partners, different types of polyethylenes with various molecular weights undergo complete conversion into useful liquid fuels and waxes. This method shows excellent selectivity for linear alkane formation, and the degradation product distribution (liquid fuels versus waxes) can be controlled by the catalyst structure and reaction time. In addition, the catalysts are compatible with various polyolefin additives; therefore, common plastic wastes, such as postconsumer polyethylene bottles, bags, and films could be converted into valuable chemical feedstocks without any pretreatment. PMID:27386559

  10. Effect of surface condition on the aqueous corrosion behavior of iron aluminies

    SciTech Connect

    Buchanan, R.A.; Perrin, R.L.

    1995-08-01

    The effects of retained high-temperature surface oxides, produced during thermomechanical processing and/or heat treatment, on the aqueous-corrosion characteristics of Fe-Al-based alloys were evaluated by electrochemical methods. Cyclic anodic polarization evaluations were conducted at room temperature in a mild acid-chloride solution (pH = 4,200 ppm Cl{sup {minus}}) on the Fe{sub 3}Al-based iron aluminides, FA-84 (Fe-28Al-2Cr-0.05B, at %), FA-129 (Fe-28Al-5Cr-0.5Nb-0.2C, at %), and FAL-Mo (Fe-28Al-5Cr-1Mo-0.04B-0.08Zr, at %), on the FeAl-based iron aluminide, FA-385 (Fe-35.65Al-0.20Mo-0.05Zr-0.11C, at %). The surface conditions evaluated were: As received (i.e. with the retained high-temperature oxides), mechanically cleaned (ground through 600-grit SiC paper), and chemically cleaned (10% HNO{sub 3}, 2%HF, at 43 {degree}C). The principal electrochemical parameter of interest was the critical putting potential with lower values indicating less resistance to chloride-induced localized corrosion. For all materials evaluated, the critical pitting potential was found to be significantly lower in the as-received condition than in the mechanically-cleaned and chemically-cleaned conditions. Mechanisms responsible for the detrimental high-temperature-oxide effect are under study.

  11. Hetropolyacid-Catalyzed Oxidation of Glycerol into Lactic Acid under Mild Base-Free Conditions.

    PubMed

    Tao, Meilin; Yi, Xiaohu; Delidovich, Irina; Palkovits, Regina; Shi, Junyou; Wang, Xiaohong

    2015-12-21

    Lactic acid (LA) is a versatile platform molecule owing to the opportunity to transform this compound into useful chemicals and materials. Therefore, efficient production of LA based on inexpensive renewable feedstocks is of utmost importance for insuring its market availability. Herein, we report the efficient conversion of glycerol into LA catalyzed by heteropolyacids (HPAs) under mild base-free conditions. The catalytic performance of molecular HPAs appears to correlate with their redox potential and Brønsted acidity. Namely, H3 PMo(12)O(40) (HPMo) exhibits the best selectivity towards LA (90 %) with 88 % conversion of glycerol. Loading of HPMo onto a carbon support (HPMo/C) further improves LA productivity resulting in 94 % selectivity at 98 % conversion under optimized reaction conditions. The reaction takes place through the formation of dihydroxyacetone/glyceraldehyde and pyruvaldehyde as intermediates. No leaching of HPMo was observed under the applied reaction conditions and HPMo/C could be recycled 5 times without significant loss of activity.

  12. Chemoselective Oxidation of Benzyl, Amino, and Propargyl Alcohols to Aldehydes and Ketones under Mild Reaction Conditions

    PubMed Central

    Reddy, C B Rajashekar; Reddy, Sabbasani Rajasekhara; Naidu, Shivaji

    2015-01-01

    Catalytic oxidation reactions often suffer from drawbacks such as low yields and poor selectivity. Particularly, selective oxidation of alcohols becomes more difficult when a compound contains more than one oxidizable functional group. In order to deliver a methodology that addresses these issues, herein we report an efficient, aerobic, chemoselective and simplified approach to oxidize a broad range of benzyl and propargyl alcohols containing diverse functional groups to their corresponding aldehydes and ketones in excellent yields under mild reaction conditions. Optimal yields were obtained at room temperature using 1 mmol substrate, 10 mol % copper(I) iodide, 10 mol % 4-dimethylaminopyridine (DMAP), and 1 mol % 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) in acetonitrile, under an oxygen balloon. The catalytic system can be applied even when sensitive and oxidizable groups such as alkynes, amines, and phenols are present; starting materials and products containing such groups were found to be stable under the developed conditions. PMID:25969806

  13. Chemoselective Oxidation of Benzyl, Amino, and Propargyl Alcohols to Aldehydes and Ketones under Mild Reaction Conditions.

    PubMed

    Reddy, C B Rajashekar; Reddy, Sabbasani Rajasekhara; Naidu, Shivaji

    2015-04-01

    Catalytic oxidation reactions often suffer from drawbacks such as low yields and poor selectivity. Particularly, selective oxidation of alcohols becomes more difficult when a compound contains more than one oxidizable functional group. In order to deliver a methodology that addresses these issues, herein we report an efficient, aerobic, chemoselective and simplified approach to oxidize a broad range of benzyl and propargyl alcohols containing diverse functional groups to their corresponding aldehydes and ketones in excellent yields under mild reaction conditions. Optimal yields were obtained at room temperature using 1 mmol substrate, 10 mol % copper(I) iodide, 10 mol % 4-dimethylaminopyridine (DMAP), and 1 mol % 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) in acetonitrile, under an oxygen balloon. The catalytic system can be applied even when sensitive and oxidizable groups such as alkynes, amines, and phenols are present; starting materials and products containing such groups were found to be stable under the developed conditions. PMID:25969806

  14. Synthesis of boron suboxide from boron and boric acid under mild pressure and temperature conditions

    SciTech Connect

    Jiao, Xiaopeng; Jin, Hua; Ding, Zhanhui; Yang, Bin; Lu, Fengguo; Zhao, Xudong; Liu, Xiaoyang; Peng, Liping

    2011-05-15

    Graphical abstract: Well-crystallized and icosahedral B{sub 6}O crystals were prepared by reacting boron and boric acid at milder reaction conditions (1 GPa and 1300 {sup o}C for 2 h) as compared to previous work.. Research highlights: {yields} Well-crystallized icosahedral B{sub 6}O was synthesized by reacting boric acid and boron. {yields} The synthesis conditions (1 GPa and 1300 {sup o}C for 2 h) are milder in comparison with previous work. {yields} The more practical synthesis method may make B{sub 6}O as a potential substitute for diamond in industry. -- Abstract: Boron suboxide (B{sub 6}O) was synthesized by reacting boron and boric acid (H{sub 3}BO{sub 3}) at pressures between 1 and 10 GPa, and at temperatures between 1300 and 1400 {sup o}C. The B{sub 6}O samples prepared were icosahedral with diameters ranging from 20 to 300 nm. Well-crystallized and icosahedral crystals with an average size of {approx}100 nm can be obtained at milder reaction conditions (1 GPa and 1300 {sup o}C for 2 h) as compared to previous work. The bulk B{sub 6}O sample was stable in air at 600 {sup o}C and then slowly oxidized up to 1000 {sup o}C. The relatively mild synthetic conditions developed in this study provide a more practical synthesis of B{sub 6}O, which may potentially be used as a substitute for diamond in industry as a new superhard material.

  15. Sterically-controlled intermolecular Friedel-Crafts acylation with twisted amides via selective N-C cleavage under mild conditions.

    PubMed

    Liu, Yongmei; Meng, Guangrong; Liu, Ruzhang; Szostak, Michal

    2016-05-21

    Highly chemoselective Friedel-Crafts acylation with twisted amides under mild conditions is reported for the first time. The reaction shows high functional group tolerance, obviating the need for preformed sensitive organometallic reagents and expensive transition metal catalysts. The high reactivity of amides is switched on by ground-state steric distortion to disrupt the amide bond nN→πCO* resonance as a critical design feature. Conceptually, this new acid-promoted mechanism of twisted amides provides direct access to bench-stable acylating reagents under mild, metal-free conditions. PMID:27139813

  16. Optical spectroscopy of simple aqueous solutions under extreme conditions

    NASA Astrophysics Data System (ADS)

    Vass, H.; Edington, D.; Crain, J.

    2003-06-01

    We report the results of an extensive series of Brillouin scattering experiments on simple aqueous solutions with a view to exploring their dynamical properties over a wide range of temperatures and pressures. For all solutes studied that inhibit freezing and allow access to temperatures far below the normal supercooling limit of water, we find clear spectroscopic evidence of GHz-range viscoelastic behavior below ≈-40 °C. This is manifested by a dramatic rise in the Brillouin mode frequencies accompanied by initial broadening and subsequent narrowing of the spectral linewidths on cooling. We find similar behavior in pure compressed (to between 2 and 4 kbar) supercooled water. This suggests that the low-temperature viscoelastic dynamics of these solutions is dominated by the behavior of the aqueous component which evidently exhibits a pronounced decrease in relaxation time though the temperature range over which it occurs is inaccessible unless freezing is suppressed either by pressure or the presence of solutes. No firm conclusion can be drawn concerning the proposed second critical point at these very low temperatures though it is not required for a consistent interpretation of the data. In the high-temperature regime, where the hydrogen bond structure is disrupted, we find considerable chemical sensitivity (even among the three chloride salts NaCl, CsCl, and CaCl2) in the dynamics especially in the vicinity of the liquid-gas critical point. This is in contrast to the low-temperature case where the cooperative dynamics of the water network dominates and appears to remain intact in the presence of a wide variety of solutes.

  17. Reusable task-specific ionic liquids for a clean ε-caprolactam synthesis under mild conditions.

    PubMed

    Turgis, Raphaël; Estager, Julien; Draye, Micheline; Ragaini, Vittorio; Bonrath, Werner; Lévêque, Jean-Marc

    2010-12-17

    Brønsted-acidic ionic liquids that bear a sulfonic acid group, known as Forbes acids, show a good catalytic activity for the Beckmann rearrangement, used to prepare ε-caprolactam, which is a precursor of Nylon 6. The activity essentially stems from the acidity of the sulfonic acid group. Although these task specific ionic liquids suffer from a high viscosity, this drawback can be circumvented at higher temperatures. A combination of the hydrogen sulfate anion and the sulfonic acid group of the cation is needed to obtain the rearrangement product rapidly under mild conditions. When using an excess of ionic liquid, we postulate that the internal pressure of the ionic medium, generated by the high viscosity and the high number of hydrogen-bonds, is strong enough to contribute to a decrease of the thermodynamic barrier. In accordance with the "Principles of Green Chemistry," we have developed a synthesis of ε-caprolactam that requires no additional chemicals except cyclohexanone oxime and the reusable TSIL.

  18. Evolutionary optimization for conditions of variable BHF for springback reduction in AHSS-mild steel TWB

    NASA Astrophysics Data System (ADS)

    Nguyen, N.-T.; Chakraborti, N.; Barlat, F.

    2013-12-01

    In this study, the advanced high strength steels (AHSS)/mild steel TWB sheet is applied to the U-draw bending springback under non-constant blank holding force (BHF). On both sides of the blank, two different BHF-punch stroke are applied. A systematic approach to obtain optimal BHF-stroke profiles is proposed. The optimal condition would require satisfying two conflicting objectives simultaneously: (1) minimize springback deformation and (2) minimize the forming severity, leading to a Pareto-optimal problem. The optimization procedure consists of the following steps: sampling design, finite element (FE) simulations, metamodeling, and finally the calculation of a Pareto-frontier. PAM-STAMP® FE software is employed in this study. The generated outputs of FE simulations on some statistically significant sampling points are then used for the construction of metamodels of optimum accuracy and complexity, which, in turn, were used to evaluate the output for any set of inputs, replacing the computing intensive FE simulations. A novel genetic algorithms based multi-objective optimization technique is applied for optimization. Yet far to be completely removed, springback in TWB can be appreciably reduced using the proposed approach of variable BHF control.

  19. Examination of the interaction of different lighting conditions and chronic mild stress in animal model.

    PubMed

    Muller, A; Gal, N; Betlehem, J; Fuller, N; Acs, P; Kovacs, G L; Fusz, K; Jozsa, R; Olah, A

    2015-09-01

    We examined the effects of different shift work schedules and chronic mild stress (CMS) on mood using animal model. The most common international shift work schedules in nursing were applied by three groups of Wistar-rats and a control group with normal light-dark cycle. One subgroup from each group was subjected to CMS. Levels of anxiety and emotional life were evaluated in light-dark box. Differences between the groups according to independent and dependent variables were examined with one- and two-way analysis of variance, with a significance level defined at p < 0.05. Interaction of lighting regimen and CMS was proved to be significant according to time spent in the light compartment and the average number of changes between the light and dark compartments. Results of our examination confirm that the changes of lighting conditions evocate anxiety more prominently than CMS. No significant differences were found between the results of the low rotating group and the control group, supposing that this schedule is the least harmful to health. Our results on the association between the use of lighting regimens and the level of CMS provide evidence that the fast rotating shift work schedule puts the heaviest load on the organism of animals.

  20. Addition of ethylene or hydrogen to a main-group metal cluster under mild conditions.

    PubMed

    Vasko, Petra; Wang, Shuai; Tuononen, Heikki M; Power, Philip P

    2015-03-16

    Reaction of the tin cluster Sn8(Ar(Me6))4(Ar(Me6)=C6H2-2,6-(C6H3-2,4,6-Me3)2) with excess ethylene or dihydrogen at 25 °C/1 atmosphere yielded two new clusters that incorporated ethylene or hydrogen. The reaction with ethylene yielded Sn4(Ar(Me6))4(C2H2)5 that contained five ethylene moieties bridging four aryl substituted tin atoms and one tin-tin bond. Reaction with H2 produced a cyclic tin species of formula (Sn(H)Ar(Me6))4, which could also be synthesized by the reaction of {(Ar(Me6))Sn(μ-Cl)}2 with DIBAL-H. These reactions represent the first instances of direct reactions of isolable main-group clusters with ethylene or hydrogen under mild conditions. The products were characterized in the solid state by X-ray diffraction and IR spectroscopy and in solution by multinuclear NMR and UV/Vis spectroscopies. Density functional theory calculations were performed to explain the reactivity of the cluster.

  1. Transition-Metal-Mediated Cleavage of Fluoro-Silanes under Mild Conditions.

    PubMed

    Kameo, Hajime; Kawamoto, Tatsuya; Sakaki, Shigeyoshi; Bourissou, Didier; Nakazawa, Hiroshi

    2016-02-12

    Si-F bond cleavage of fluoro-silanes was achieved by transition-metal complexes under mild and neutral conditions. The Iridium-hydride complex [Ir(H)(CO)(PPh3 )3 ] was found to readily break the Si-F bond of the diphosphine- difluorosilane {(o-Ph2 P)C6 H4 }2 Si(F)2 to afford a silyl complex [{[o-(iPh2 P)C6 H4 ]2 (F)Si}Ir(CO)(PPh3 )] and HF. Density functional theory calculations disclose a reaction mechanism in which a hypervalent silicon species with a dative Ir→Si interaction plays a crucial role. The Ir→Si interaction changes the character of the H on the Ir from hydridic to protic, and makes the F on Si more anionic, leading to the formation of H(δ+) ⋅⋅⋅F(δ-) interaction. Then the Si-F and Ir-H bonds are readily broken to afford the silyl complex and HF through σ-bond metathesis. Furthermore, the analogous rhodium complex [Rh(H)(CO)(PPh3 )3 ] was found to promote the cleavage of the Si-F bond of the triphosphine-monofluorosilane {(o-Ph2 P)C6 H4 }3 Si(F) even at ambient temperature. PMID:26836576

  2. Merging Photoredox with Palladium Catalysis: Decarboxylative ortho-Acylation of Acetanilides with α-Oxocarboxylic Acids under Mild Reaction Conditions.

    PubMed

    Zhou, Chao; Li, Pinhua; Zhu, Xianjin; Wang, Lei

    2015-12-18

    A room temperature decarboxylative ortho-acylation of acetanilides with α-oxocarboxylic acids has been developed via a novel Eosin Y with Pd dual catalytic system. This dual catalytic reaction shows a broad substrate scope and good functional group tolerance, and an array of ortho-acylacetanilides can be afforded in high yields under mild conditions.

  3. Promising hydrogen storage properties and potential applications of Mg-Al-Pd trilayer films under mild conditions.

    PubMed

    Xin, Gongbiao; Yang, Junzhi; Zhang, Guoqing; Zheng, Jie; Li, Xingguo

    2012-10-14

    We prepared a series of nano-sized Mg-Al-Pd trilayer films and investigated their hydrogen storage properties under mild conditions. Results showed that Al 1 nm sample had the best absorption kinetics and excellent optical properties at room temperature, making it a promising candidate for hydrogen sensors and smart windows. PMID:22692459

  4. Investigation of acyl migration in mono- and dicaffeoylquinic acids under aqueous basic, aqueous acidic, and dry roasting conditions.

    PubMed

    Deshpande, Sagar; Jaiswal, Rakesh; Matei, Marius Febi; Kuhnert, Nikolai

    2014-09-17

    Acyl migration in chlorogenic acids describes the process of migration of cinnamoyl moieties from one quinic acid alcohol group to another, thus interconverting chlorogenic acid regioisomers. It therefore constitutes a special case of transesterification reaction. Acyl migration constitutes an important reaction pathway in both coffee roasting and brewing, altering the structure of chlorogenic acid initially present in the green coffee bean. In this contribution we describe detailed and comprehensive mechanistic studies comparing inter- and intramolecular acyl migration involving the seven most common chlorogenic acids in coffee. We employe aqueous acidic and basic conditions mimicking the brewing of coffee along with dry roasting conditions. We show that under aqueous basic conditions intramolecular acyl migration is fully reversible with basic hydrolysis competing with acyl migration. 3-Caffeoylquinic acid was shown to be most labile to basic hydrolysis. We additionally show that the acyl migration process is strongly pH dependent with increased transesterification taking place at basic pH. Under dry roasting conditions acyl migration competes with dehydration to form lactones. We argue that acyl migration precedes lactonization, with 3-caffeoylquinic acid lactone being the predominant product.

  5. Experimental Low Temperature Aqueous Alteration of Allende Under Reducing Conditions

    NASA Astrophysics Data System (ADS)

    Duke, C. L.; Brearley, A. J.

    1999-03-01

    This abstract presents the results of a series of low temperature hydrothermal alteration experiments that were carried out in an anoxic environment. The results are compared with the results of previous experiments run under oxidizing conditions.

  6. Green Catalytic Process for Cyclic Carbonate Synthesis from Carbon Dioxide under Mild Conditions.

    PubMed

    Lang, Xian-Dong; He, Liang-Nian

    2016-06-01

    As a renewable and abundant C1 resource possessing multiple attractive characteristics, such as low cost, nontoxicity, non-flammability, and easy accessibility, CO2 conversion into value-added chemicals and fuels can contribute to green chemistry and sustainable development. Since CO2 is a thermodynamically inert molecule, the activation of CO2 is pivotal for its effective conversion. In this regard, the formation of a transition-metal CO2 complex through direct coordination is one of the most powerful ways to induce the inert CO2 molecule to undergo chemical reactions. To date, numerous processes have been developed for efficient synthesis of cyclic carbonates from CO2 . On the basis of mechanistic understanding, we have developed efficient metal catalysts and green processes, including heterogeneous catalysis, and metal-free systems, such as ionic liquids, for cyclic carbonate synthesis. The big challenge is to develop catalysts that promote the reaction under low pressure (preferably at 1 bar). In this context, bifunctional catalysis is capable of synergistic activation of both the substrate and CO2 molecule, and thus, could render CO2 conversion smoothly under mild conditions. Alternatively, converting CO2 derivatives, that is, the captured CO2 as an activated species, would more easily take place at low pressure in comparison with gaseous CO2 . The aim of this Personal Account is to summarize versatile catalytic processes for cyclic carbonate synthesis from CO2 , including epoxide/CO2 coupling reaction, carboxylation of 1,2-diol with CO2 , oxidative cyclization of olefins with CO2 , condensation of vicinal halohydrin with CO2 , carboxylative cyclization of propargyl alcohols with CO2 , and conversion of the CO2 derivatives. PMID:27121768

  7. Elephant Moraine 96029, a very mildly aqueously altered and heated CM carbonaceous chondrite: Implications for the drivers of parent body processing

    NASA Astrophysics Data System (ADS)

    Lee, Martin R.; Lindgren, Paula; King, Ashley J.; Greenwood, Richard C.; Franchi, Ian A.; Sparkes, Robert

    2016-08-01

    Elephant Moraine (EET) 96029 is a CM carbonaceous chondrite regolith breccia with evidence for unusually mild aqueous alteration, a later phase of heating and terrestrial weathering. The presence of phyllosilicates and carbonates within chondrules and the fine-grained matrix indicates that this meteorite was aqueously altered in its parent body. Features showing that water-mediated processing was arrested at a very early stage include a matrix with a low magnesium/iron ratio, chondrules whose mesostasis contains glass and/or quench crystallites, and a gehlenite-bearing calcium- and aluminium-rich inclusion. EET 96029 is also rich in Fe,Ni metal relative to other CM chondrites, and more was present prior to its partial replacement by goethite during Antarctic weathering. In combination, these properties indicate that EET 96029 is one of the least aqueously altered CMs yet described (CM2.7) and so provides new insights into the original composition of its parent body. Following aqueous alteration, and whilst still in the parent body regolith, the meteorite was heated to ∼400-600 °C by impacts or solar radiation. Heating led to the amorphisation and dehydroxylation of serpentine, replacement of tochilinite by magnetite, loss of sulphur from the matrix, and modification to the structure of organic matter that includes organic nanoglobules. Significant differences between samples in oxygen isotope compositions, and water/hydroxyl contents, suggests that the meteorite contains lithologies that have undergone different intensities of heating. EET 96029 may be more representative of the true nature of parent body regoliths than many other CM meteorites, and as such can help interpret results from the forthcoming missions to study and return samples from C-complex asteroids.

  8. TOPEX/El Nino Watch - Mild La Nina Conditions Developing, November 12, 1999

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Unusually warm ocean temperatures off Asia and cool waters in the eastern and equatorial Pacific are signaling La Nina's mild return, according to the latest sea-surface heights observed by the joint NASA-French space agency's TOPEX/Poseidon satellite.

    Lower than normal sea-surface heights in the eastern North Pacific and abnormally high sea-surface heights in the western and mid-latitude Pacific are expected to drive storms coming out of the Pacific this winter, the mission data indicate. Those conditions will most likely steer storms north into the Pacific Northwest and keep the southwestern United States dryer than normal.

    The latest measurements, processed after a 10-day data cycle November 4-13 at NASA's Jet Propulsion Laboratory, Pasadena, CA, are available at http://www.jpl.nasa.gov/elnino . Sea-surface height is shown relative to normal (green) and reveals cooler water(blue and purple) measuring between 8 and 24 centimeters (3 to 9 inches) lower than average in the eastern North Pacific, from the Gulf of Alaska to central Alaska, and along the equator.

    Unusual conditions persist in the western and mid-latitude Pacific Ocean as well, with higher than average sea-surface heights(red and white) of between 8 and 24 centimeters (3 to 9 inches). These areas of increased sea-surface height and unusually warm water were present last year, but the increase in height has surpassed last year's measurements.

    The TOPEX/Poseidon satellite's measurements over the last seven and a half years have provided scientists with a comprehensive record of the 1997-1999 El Nino/La Nina climate pattern by measuring changing sea-surface heights to within 4centimeters (1.5 inches) precision.

    The U.S./French mission is managed by the Jet Propulsion Laboratory for NASA's Earth Sciences Enterprise, Washington, DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

    For more information, please visit the TOPEX/Poseidon project web page at http://topex-www.jpl.nasa.gov/

  9. Aqueous alteration of VHTR fuels particles under simulated geological conditions

    NASA Astrophysics Data System (ADS)

    Ait Chaou, Abdelouahed; Abdelouas, Abdesselam; Karakurt, Gökhan; Grambow, Bernd

    2014-05-01

    Very High Temperature Reactor (VHTR) fuels consist of the bistructural-isotropic (BISO) or tristructural-isotropic (TRISO)-coated particles embedded in a graphite matrix. Management of the spent fuel generated during VHTR operation would most likely be through deep geological disposal. In this framework we investigated the alteration of BISO (with pyrolytic carbon) and TRISO (with SiC) particles under geological conditions simulated by temperatures of 50 and 90 °C and in the presence of synthetic groundwater. Solid state (scanning electron microscopy (SEM), micro-Raman spectroscopy, electron probe microanalyses (EPMA) and X-ray photoelectron spectroscopy (XPS)) and solution analyses (ICP-MS, ionique chromatography (IC)) showed oxidation of both pyrolytic carbon and SiC at 90 °C. Under air this led to the formation of SiO2 and a clay-like Mg-silicate, while under reducing conditions (H2/N2 atmosphere) SiC and pyrolytic carbon were highly stable after a few months of alteration. At 50 °C, in the presence and absence of air, the alteration of the coatings was minor. In conclusion, due to their high stability in reducing conditions, HTR fuel disposal in reducing deep geological environments may constitute a viable solution for their long-term management.

  10. Effects of mild wintering conditions on body mass and corticosterone levels in a temperate reptile, the aspic viper (Vipera aspis).

    PubMed

    Brischoux, François; Dupoué, Andréaz; Lourdais, Olivier; Angelier, Frédéric

    2016-02-01

    Temperate ectotherms are expected to benefit from climate change (e.g., increased activity time), but the impacts of climate warming during the winter have mostly been overlooked. Milder winters are expected to decrease body condition upon emergence, and thus to affect crucial life-history traits, such as survival and reproduction. Mild winter temperature could also trigger a state of chronic physiological stress due to inadequate thermal conditions that preclude both dormancy and activity. We tested these hypotheses on a typical temperate ectothermic vertebrate, the aspic viper (Vipera aspis). We simulated different wintering conditions for three groups of aspic vipers (cold: ~6 °C, mild: ~14 °C and no wintering: ~24 °C) during a one month long period. We found that mild wintering conditions induced a marked decrease in body condition, and provoked an alteration of some hormonal mechanisms involved in emergence. Such effects are likely to bear ultimate consequences on reproduction, and thus population persistence. We emphasize that future studies should incorporate the critical, albeit neglected, winter season when assessing the potential impacts of global changes on ectotherms.

  11. Single step signal group-imidazole labeling of organic phosphate groups under aqueous conditions

    DOEpatents

    Giese, R.W.; Wang, P.

    1996-04-30

    Compounds and methods for single step, covalent labeling of the phosphate group of an organic substance under aqueous conditions are described. The labeling compound includes any kind of detectable signal group covalently bound to an imidazole moiety, which can be imidazole or a substituted imidazole. A preferred labeling compound has the formula shown in the accompanying diagram. 4 figs.

  12. Single step signal group-imidazole labeling of organic phosphate groups under aqueous conditions

    DOEpatents

    Giese, Roger W.; Wang, Poguang

    1996-01-01

    Compounds and methods for single step, covalent labeling of the phosphate group of an organic substance under aqueous conditions are described. The labeling compound includes any kind of detectable signal group covalently bound to an imidazole moiety, which can be imidazole or a substituted imidazole. A preferred labeling compound has the formula ##STR1##

  13. Corrosion inhibition of aminated hydroxyl ethyl cellulose on mild steel in acidic condition.

    PubMed

    Sangeetha, Y; Meenakshi, S; Sairam Sundaram, C

    2016-10-01

    Aminated hydroxyethyl cellulose (AHEC) was synthesized, characterized using Fourier Transform Infrared spectroscopy (FTIR) and the corrosion inhibition of AHEC on mild steel in 1M HCl was studied using chemical and electrochemical studies. Results obtained in weight loss method showed that inhibition efficiency increased with increase in concentration of AHEC. The adsorption of the inhibitor on metal surface followed Frumkin isotherm. Polarization studies revealed that the AHEC inhibits through mixed mode. Thermodynamic parameters and activation energy were calculated and discussed. FTIR and X-ray diffraction studies (XRD) confirmed the adsorption of the inhibitor. The surface morphology was studied using Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM).

  14. Corrosion inhibition of aminated hydroxyl ethyl cellulose on mild steel in acidic condition.

    PubMed

    Sangeetha, Y; Meenakshi, S; Sairam Sundaram, C

    2016-10-01

    Aminated hydroxyethyl cellulose (AHEC) was synthesized, characterized using Fourier Transform Infrared spectroscopy (FTIR) and the corrosion inhibition of AHEC on mild steel in 1M HCl was studied using chemical and electrochemical studies. Results obtained in weight loss method showed that inhibition efficiency increased with increase in concentration of AHEC. The adsorption of the inhibitor on metal surface followed Frumkin isotherm. Polarization studies revealed that the AHEC inhibits through mixed mode. Thermodynamic parameters and activation energy were calculated and discussed. FTIR and X-ray diffraction studies (XRD) confirmed the adsorption of the inhibitor. The surface morphology was studied using Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM). PMID:27312608

  15. Selective production of hemicellulose-derived carbohydrates from wheat straw using dilute HCl or FeCl3 solutions under mild conditions. X-ray and thermo-gravimetric analysis of the solid residues.

    PubMed

    Marcotullio, G; Krisanti, E; Giuntoli, J; de Jong, W

    2011-05-01

    The present work explores the combined production of hemicellulose-derived carbohydrates and an upgraded solid residue from wheat straw using a dilute-acid pretreatment at mild temperature. Dilute aqueous HCl solutions were studied at temperatures of 100 and 120°C, and they were compared to dilute FeCl(3) under the same conditions. Comparable yields of soluble sugars and acetic acid were obtained, affording an almost complete removal of pentoses when using 200 mM aqueous solutions at 120°C. The solid residues of pretreatment were characterized showing a preserved crystallinity of the cellulose, and a almost complete removal of ash forming matter other than Si. Results showed upgraded characteristic of the residues for thermal conversion applications compared to the untreated wheat straw.

  16. Corrosion of mild steel exposed to inhibited urea--ammonium nitrate solution at ambient temperature under static conditions

    SciTech Connect

    Nguyen, D.T.; Nichols, D.E.; Boles, J.L.; Lohry, E.J.

    1991-12-31

    A series of corrosion tests was performed with mild steel exposed to 32-0-0 UAN solution at ambient temperature, under static conditions, and at pHs of 6.8 to 7.2 to evaluate the effectiveness of several new corrosion inhibitors. Results of the tests revealed that the pH of 32-0-0 UAN in the neutral range does not significantly affect the corrosion rate of mild steel after prolonged exposure. The corrosion rate of mild steel was 60 to 70 mpy. Results of tests with inhibitors showed that 100 ppm of Surtech 143 from Surface Chemists of Florida, Inc., provided excellent corrosion resistance (approximately 1 mpy after long-term exposure). With a 5-minute surface treatment, Rust Resistor from Nutra-Flo Co., provided excellent corrosion resistance (corrosion rates less than 1 mpy). Corblok at 100 ppM provided excellent corrosion resistance up to 14 days (corrosion rate of approximately 2 mpy); the corrosion rate increased slightly when exposed for 28 days. Surtech 145 and Surtech 433 provided only limited protection.

  17. Corrosion of mild steel exposed to inhibited urea--ammonium nitrate solution at ambient temperature under static conditions

    SciTech Connect

    Nguyen, D.T.; Nichols, D.E.; Boles, J.L. ); Lohry, E.J. )

    1991-01-01

    A series of corrosion tests was performed with mild steel exposed to 32-0-0 UAN solution at ambient temperature, under static conditions, and at pHs of 6.8 to 7.2 to evaluate the effectiveness of several new corrosion inhibitors. Results of the tests revealed that the pH of 32-0-0 UAN in the neutral range does not significantly affect the corrosion rate of mild steel after prolonged exposure. The corrosion rate of mild steel was 60 to 70 mpy. Results of tests with inhibitors showed that 100 ppm of Surtech 143 from Surface Chemists of Florida, Inc., provided excellent corrosion resistance (approximately 1 mpy after long-term exposure). With a 5-minute surface treatment, Rust Resistor from Nutra-Flo Co., provided excellent corrosion resistance (corrosion rates less than 1 mpy). Corblok at 100 ppM provided excellent corrosion resistance up to 14 days (corrosion rate of approximately 2 mpy); the corrosion rate increased slightly when exposed for 28 days. Surtech 145 and Surtech 433 provided only limited protection.

  18. Efficient and facile one pot carboxylation of multiwalled carbon nanotubes by using oxidation with ozone under mild conditions

    NASA Astrophysics Data System (ADS)

    Naeimi, Hossein; Mohajeri, Ali; Moradi, Leila; Rashidi, Ali Morad

    2009-11-01

    In this study, oxidation of carbon nanotubes with ozone in the presence of hydrogen peroxide was investigated. The reaction was performed under clean and mild conditions and oxidized products with high concentration of oxygenated groups were yielded. The reaction products were characterized with attenuated total reflectance (ATR), Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffractometry (XRD), back titration, X-ray photoelectron spectroscopy (XPS) and the dispersion behavior of the oxidized multiwalled carbon nanotubes (MWCNTs) was also studied. The results confirmed the presence of high concentrations of oxidative groups on the carbon nanotubes (CNTs) treated by the method of the present work.

  19. Mild conditions for deuteration of primary and secondary arylamines for the synthesis of deuterated optoelectronic organic molecules.

    PubMed

    Krause-Heuer, Anwen M; Yepuri, Nageshwar R; Darwish, Tamim A; Holden, Peter J

    2014-11-13

    Deuterated arylamines demonstrate great potential for use in optoelectronic devices, but their widespread utility requires a method for large-scale synthesis. The incorporation of these deuterated materials into optoelectronic devices also provides the opportunity for studies of the functioning device using neutron reflectometry based on the difference in the scattering length density between protonated and deuterated compounds. Here we report mild deuteration conditions utilising standard laboratory glassware for the deuteration of: diphenylamine, N-phenylnaphthylamine, N-phenyl-o-phenylenediamine and 1-naphthylamine (via H/D exchange in D2O at 80 °C, catalysed by Pt/C and Pd/C). These conditions were not successful in the deuteration of triphenylamine or N,N-dimethylaniline, suggesting that these mild conditions are not suitable for the deuteration of tertiary arylamines, but are likely to be applicable for the deuteration of other primary and secondary arylamines. The deuterated arylamines can then be used for synthesis of larger organic molecules or polymers with optoelectronic applications.

  20. Efficient conversion of brown grease produced by municipal wastewater treatment plant into biofuel using aluminium chloride hexahydrate under very mild conditions.

    PubMed

    Pastore, Carlo; Lopez, Antonio; Mascolo, Giuseppe

    2014-03-01

    Wastes produced by oil/water separation at the wastewater treatment plant of Bari West (Southern Italy) were taken, characterized and converted. About 12% of this material was composed of greases, mainly made of free fatty acids (50%) and soaps (34%), and was easily separable by the aqueous phase through a hot centrifugation. After chemical activation of this fatty fraction, a direct esterification was carried out under very mild conditions (320K and atmospheric pressure), converting more than 90% of the original free fatty acids into the respective methyl esters in less than 4h, by using AlCl3·6H2O. The activation energy correlated to the use of this catalyst was also calculated (Eaest=43.9kJmol(-1)). The very low cost of the biodiesel produced (0.45€L(-1)) and the associated relevant specific energy (5.02MJ kgFAMEs(-1)) make such a process a really sustainable and effective example of valorization of a waste.

  1. Efficient conversion of brown grease produced by municipal wastewater treatment plant into biofuel using aluminium chloride hexahydrate under very mild conditions.

    PubMed

    Pastore, Carlo; Lopez, Antonio; Mascolo, Giuseppe

    2014-03-01

    Wastes produced by oil/water separation at the wastewater treatment plant of Bari West (Southern Italy) were taken, characterized and converted. About 12% of this material was composed of greases, mainly made of free fatty acids (50%) and soaps (34%), and was easily separable by the aqueous phase through a hot centrifugation. After chemical activation of this fatty fraction, a direct esterification was carried out under very mild conditions (320K and atmospheric pressure), converting more than 90% of the original free fatty acids into the respective methyl esters in less than 4h, by using AlCl3·6H2O. The activation energy correlated to the use of this catalyst was also calculated (Eaest=43.9kJmol(-1)). The very low cost of the biodiesel produced (0.45€L(-1)) and the associated relevant specific energy (5.02MJ kgFAMEs(-1)) make such a process a really sustainable and effective example of valorization of a waste. PMID:24434702

  2. Stability of lysozyme in aqueous extremolyte solutions during heat shock and accelerated thermal conditions.

    PubMed

    Avanti, Christina; Saluja, Vinay; van Streun, Erwin L P; Frijlink, Henderik W; Hinrichs, Wouter L J

    2014-01-01

    The purpose of this study was to investigate the stability of lysozyme in aqueous solutions in the presence of various extremolytes (betaine, hydroxyectoine, trehalose, ectoine, and firoin) under different stress conditions. The stability of lysozyme was determined by Nile red Fluorescence Spectroscopy and a bioactivity assay. During heat shock (10 min at 70°C), betaine, trehalose, ectoin and firoin protected lysozyme against inactivation while hydroxyectoine, did not have a significant effect. During accelerated thermal conditions (4 weeks at 55°C), firoin also acted as a stabilizer. In contrast, betaine, hydroxyectoine, trehalose and ectoine destabilized lysozyme under this condition. These findings surprisingly indicate that some extremolytes can stabilize a protein under certain stress conditions but destabilize the same protein under other stress conditions. Therefore it is suggested that for the screening extremolytes to be used for protein stabilization, an appropriate storage conditions should also be taken into account.

  3. Reversible Hydrogen Storage using CO2 and a Proton-Switchable Iridium Catalyst in Aqueous Media under Mild Temperatures and Pressures

    SciTech Connect

    Hull J. F.; Himeda, Y.; Wang, W.-H.; Hashiguchi, B.; Szalda, D.J.; Muckerman, J.T.; Fujita, E.

    2012-05-01

    Green plants convert CO{sub 2} to sugar for energy storage via photosynthesis. We report a novel catalyst that uses CO{sub 2} and hydrogen to store energy in formic acid. Using a homogeneous iridium catalyst with a proton-responsive ligand, we show the first reversible and recyclable hydrogen storage system that operates under mild conditions using CO{sub 2}, formate and formic acid. This system is energy-efficient and green because it operates near ambient conditions, uses water as a solvent, produces high-pressure CO-free hydrogen, and uses pH to control hydrogen production or consumption. The extraordinary and switchable catalytic activity is attributed to the multifunctional ligand, which acts as a proton-relay and strong {pi}-donor, and is rationalized by theoretical and experimental studies.

  4. Production of starch nanoparticles using normal maize starch via heat-moisture treatment under mildly acidic conditions and homogenization.

    PubMed

    Park, Eun Young; Kim, Min-Jung; Cho, MyoungLae; Lee, Ju Hun; Kim, Jong-Yea

    2016-10-20

    Normal maize starch was subjected to heat-moisture treatment (HMT) under mildly acidic conditions (0.000, 0.050, or 0.075M H2SO4) for various treatment times (3, 5, or 8h) followed by homogenization up to 60min to prepare nanoparticles. The combination of HMT (0.075M, for 8h) and homogenization (60min) produced nanoparticles with diameters of less than 50nm at a yield higher than 80%. X-ray diffractometry and size-exclusion chromatography revealed that HMT under mildly acidic conditions selectively hydrolyzed the starch chains (especially amylose and/or long chains of amylopectin) in the amorphous region of the granules without significant damage to the crystalline structure, however, modification of the molecular structure in the amorphous region increased fragility of the granules during homogenization. Homogenization for 60min caused obvious damage in the long-range crystalline structure of the HMT starch (0.15N, for 8h), while the short-range chain associations (FT-IR) remained intact. PMID:27474568

  5. A new class of single-component absorbents for reversible carbon dioxide capture under mild conditions.

    PubMed

    Barzagli, Francesco; Lai, Sarah; Mani, Fabrizio

    2015-01-01

    Some inexpensive and commercially available secondary amines reversibly react with CO2 at room temperature and ambient pressure to yield carbonated species in the liquid phase in the absence of any additional solvent. These solvent-free absorbents have a high CO2 capture capacity (0.63-0.65 mol CO2 /mol amine) at 1.0 bar (=100 kPa), combined with low-temperature reversibility at ambient pressure. (13) C NMR spectroscopy analysis identified the carbonated species as the carbamate salts and unexpected carbamic acids. These absorbents were used for CO2 (15 and 40 % in air) capture in continuous cycles of absorption-desorption carried out in packed columns, yielding an absorption efficiency of up to 98.5 % at absorption temperatures of 40-45 °C and desorption temperatures of 70-85 °C at ambient pressure. The absence of any parasitic solvent that requires to be heated and stability towards moisture and heating could result in some of these solvent-free absorbents being a viable alternative to aqueous amines for CO2 chemical capture.

  6. Existence of mild solution of impulsive quantum stochastic differential equation with nonlocal conditions

    NASA Astrophysics Data System (ADS)

    Bishop, S. A.; Ayoola, E. O.; Oghonyon, G. J.

    2016-08-01

    New results on existence and uniqueness of solution of impulsive quantum stochastic differential equation with nonlocal conditions are established. The nonlocal conditions are completely continuous. The methods applied here are simple extension of the methods applied in the classical case to this noncummutative quantum setting.

  7. Intrinsic formation of nanocrystalline neptunium dioxide under neutral aqueous conditions relevant to deep geological repositories.

    PubMed

    Husar, Richard; Hübner, René; Hennig, Christoph; Martin, Philippe M; Chollet, Mélanie; Weiss, Stephan; Stumpf, Thorsten; Zänker, Harald; Ikeda-Ohno, Atsushi

    2015-01-25

    The dilution of aqueous neptunium carbonate complexes induces the intrinsic formation of nanocrystalline neptunium dioxide (NpO2) particles, which are characterised by UV/Vis and X-ray absorption spectroscopies and transmission electron microscopy. This new route of nanocrystalline NpO2 formation could be a potential scenario for the environmental transport of radionuclides from the waste repository (i.e. under near-field alkaline conditions) to the geological environment (i.e. under far-field neutral conditions).

  8. Separation of post-translational modifications in monoclonal antibodies by exploiting subtle conformational changes under mildly acidic conditions.

    PubMed

    Wang, Shiyi; Ionescu, Roxana; Peekhaus, Norbert; Leung, Jin-Yu; Ha, Sha; Vlasak, Josef

    2010-10-15

    Chromatographic separation plays a key role in the identification, quantification, and characterization of protein variants. Here we describe separation of species containing two post-translational modifications (glycosylation and methionine oxidation) in the Fc fragment of a monoclonal antibody. The method is based on cation-exchange chromatography under mildly acidic conditions that destabilize mainly the CH2 domain. Our data suggest that the separation is not mediated by the chemical modification itself, but rather by subtle structural changes induced by the chemical modification in the domain-decoupled conformation that monoclonal antibodies adopt around pH 4. Compared to other procedures already described in the literature, this method demonstrates an improved separation and allows purification of species in the native fold for additional functional characterization. This approach of separation under conditions where the protein assumes an alternative conformation could find a more general utility for the separation of chemical modifications in proteins.

  9. Homogeneous ice freezing temperatures and ice nucleation rates of aqueous ammonium sulfate and aqueous levoglucosan particles for relevant atmospheric conditions.

    PubMed

    Knopf, Daniel Alexander; Lopez, Miguel David

    2009-09-28

    Homogeneous ice nucleation from micrometre-sized aqueous (NH4)2SO4 and aqueous levoglucosan particles is studied employing the optical microscope technique. A new experimental method is introduced that allows us to control the initial water activity of the aqueous droplets. Homogeneous ice freezing temperatures and ice melting temperatures of these aqueous solution droplets, 10 to 80 microm in diameter, are determined. Homogeneous ice nucleation from aqueous (NH4)2SO4 particles 5-39 wt% in concentration and aqueous levoglucosan particles with initial water activities of 0.85-0.99 yield upper limits of the homogeneous ice nucleation rate coefficients of up to 1x10(10) cm(-3) s(-1). The experimentally derived homogeneous ice freezing temperatures and upper limits of the homogeneous ice nucleation rate coefficients are compared with corresponding predictions of the water-activity-based ice nucleation theory [T. Koop, B. P. Luo, A. Tsias and T. Peter, Nature, 2000, 406, 611]. It is found that the water-activity-based ice nucleation theory can capture the experimentally derived ice freezing temperatures and homogeneous ice nucleation rate coefficients of the aqueous (NH4)2SO4 and aqueous levoglucosan particles. However, the level of agreement between experimentally derived and predicted values, in particular for homogeneous ice nucleation rate coefficients, crucially depends on the extrapolation method to obtain water activities at corresponding freezing temperatures. It is suggested that the combination of experimentally derived ice freezing temperatures and homogeneous ice nucleation rate coefficients can serve as a better validation of the water-activity-based ice nucleation theory than when compared to the observation of homogeneous ice freezing temperatures alone. The atmospheric implications with regard to the application of the water-activity-based ice nucleation theory and derivation of maximum ice particle production rates are briefly discussed.

  10. Alumino-silicate speciation in aqueous fluids at deep crustal conditions

    NASA Astrophysics Data System (ADS)

    Mookherjee, M.; Keppler, H.; Manning, C. E.

    2014-12-01

    Alumina and silica are major oxides in most crustal rocks. While SiO2 is quite soluble in aqueous fluids at metamorphic conditions, behavior of Al2O3 in crustal metamorphic fluids has been poorly understood. It is known that alumina is dramatically less soluble in aqueous fluids and hence it is difficult to explain the common occurrence of quartz with aluminous minerals in metamorphic veins. In order to understand this complex behavior of alumina, we investigated aluminum speciation in aqueous fluids in equilibrium with corundum using in situ Raman spectroscopy in hydrothermal diamond anvil cells to 20 kbar and 1000 oC. In order to better understand the spectral features of the aqueous fluids, we used first principles simulations based on density functional theory to calculate and predict the energetics and vibrational spectra for various aluminum species that are likely to be present in aqueous solutions. The Raman spectra of pure water in equilibrium with Al2O3 are devoid of any characteristic spectral features. In contrast, aqueous fluids with KOH solution in equilibrium with Al2O3 show a sharp band at ~620 cm-1 which could be attributed to the [Al(OH)4]1- species. The band grows in intensity with temperature along an isochore. In the limited pressure, temperature and density explored in the present study, we do not find any evidence for the polymerization of the [Al(OH)4]1- species to dimers [(OH)2-Al-O2-Al(OH)2]2- or [(OH)3-Al-O-Al(OH)3]2-. This is likely due to the relatively low concentration of Al in the solutions and does not rule out significant polymerization at higher pressures and temperatures. We are also investigating the effect of SiO2 on the solubility of Al2O3 and the relative energetics of formation of pure alumina dimer [(OH)3-Al-O-Al(OH)3]2- vs. the aluminosilicate dimers, [(OH)3-Al-O-Si(OH)3]2- at deep crustal conditions. Acknowledgement- MM is supported by the US National Science Foundation grant (EAR-1250477).

  11. Mild hydrothermal conditioning prior to torrefaction and slow pyrolysis of low-value biomass.

    PubMed

    Van Poucke, R; Nachenius, R W; Agbo, K E; Hensgen, F; Bühle, L; Wachendorf, M; Ok, Y S; Tack, F M G; Prins, W; Ronsse, F; Meers, E

    2016-10-01

    The aim of this research was to establish whether hydrothermal conditioning and subsequent thermochemical processing via batch torrefaction or slow pyrolysis may improve the fuel quality of grass residues. A comparison in terms of fuel quality was made of the direct thermochemical processing of the feedstock versus hydrothermal conditioning as a pretreatment prior to thermochemical processing. Hydrothermal conditioning reduced ash content, and particularly nitrogen, potassium and chlorine contents in the biomass. The removal of volatile organic matter associated with thermochemical processes can increase the HHV to levels of volatile bituminous coal. However, slow pyrolysis only increased the HHV of biomass provided a low ash content (<6%) feedstock was used. In conclusion, hydrothermal conditioning can have a highly positive influence on the efficiency of thermochemical processes for upgrading low-value (high-ash) biomass to a higher quality fuel. PMID:26976062

  12. Mild hydrothermal conditioning prior to torrefaction and slow pyrolysis of low-value biomass.

    PubMed

    Van Poucke, R; Nachenius, R W; Agbo, K E; Hensgen, F; Bühle, L; Wachendorf, M; Ok, Y S; Tack, F M G; Prins, W; Ronsse, F; Meers, E

    2016-10-01

    The aim of this research was to establish whether hydrothermal conditioning and subsequent thermochemical processing via batch torrefaction or slow pyrolysis may improve the fuel quality of grass residues. A comparison in terms of fuel quality was made of the direct thermochemical processing of the feedstock versus hydrothermal conditioning as a pretreatment prior to thermochemical processing. Hydrothermal conditioning reduced ash content, and particularly nitrogen, potassium and chlorine contents in the biomass. The removal of volatile organic matter associated with thermochemical processes can increase the HHV to levels of volatile bituminous coal. However, slow pyrolysis only increased the HHV of biomass provided a low ash content (<6%) feedstock was used. In conclusion, hydrothermal conditioning can have a highly positive influence on the efficiency of thermochemical processes for upgrading low-value (high-ash) biomass to a higher quality fuel.

  13. Access to the Cinnoline Scaffold via Rhodium-Catalyzed Intermolecular Cyclization under Mild Conditions.

    PubMed

    Song, Chao; Yang, Chen; Zhang, Feifei; Wang, Jinhu; Zhu, Jin

    2016-09-16

    Herein, we report Rh(III)-catalyzed, N-amino (hydrazine)-directed C-H functionalization with α-diazo-β-ketoesters for access to the cinnoline scaffold. A diverse set of nondiscriminating conditions obtained for a highly efficient test transformation prompted use of a substrate-replacement technique for an in-depth search of experimental parameter space and pinpointing of the optimized conditions. A successive C-H activation/C-C coupling/intramolecular dehydration mechanistic sequence is proposed. The ability to perform gram-scale synthesis proves the synthetic utility of this simple, yet efficient, method. PMID:27584580

  14. Catalytic and regioselective oxidation of carbohydrates to synthesize keto-sugars under mild conditions.

    PubMed

    Muramatsu, Wataru

    2014-09-19

    A new catalytic and regioselective approach for the synthesis of keto-sugars is described. An organotin catalyst, Oc2SnCl2, in the presence of trimethylphenylammonium tribromide ([TMPhA](+)Br3(-)) accelerates the regioselective oxidation at the "axial"-OH group of 1,2-diol moieties in galactopyranosides. The reaction conditions can also be used for the regioselective oxidation of various carbohydrates.

  15. Folding study of Venus reveals a strong ion dependence of its yellow fluorescence under mildly acidic conditions.

    PubMed

    Hsu, Shang-Te Danny; Blaser, Georg; Behrens, Caroline; Cabrita, Lisa D; Dobson, Christopher M; Jackson, Sophie E

    2010-02-12

    Venus is a yellow fluorescent protein that has been developed for its fast chromophore maturation rate and bright yellow fluorescence that is relatively insensitive to changes in pH and ion concentrations. Here, we present a detailed study of the stability and folding of Venus in the pH range from 6.0 to 8.0 using chemical denaturants and a variety of spectroscopic probes. By following hydrogen-deuterium exchange of (15)N-labeled Venus using NMR spectroscopy over 13 months, residue-specific free energies of unfolding of some highly protected amide groups have been determined. Exchange rates of less than one per year are observed for some amide groups. A super-stable core is identified for Venus and compared with that previously reported for green fluorescent protein. These results are discussed in terms of the stability and folding of fluorescent proteins. Under mildly acidic conditions, we show that Venus undergoes a drastic decrease in yellow fluorescence at relatively low concentrations of guanidinium chloride. A detailed study of this effect establishes that it is due to pH-dependent, nonspecific interactions of ions with the protein. In contrast to previous studies on enhanced green fluorescence protein variant S65T/T203Y, which showed a specific halide ion-binding site, NMR chemical shift mapping shows no evidence for specific ion binding. Instead, chemical shift perturbations are observed for many residues primarily located in both lids of the beta-barrel structure, which suggests that small scale structural rearrangements occur on increasing ionic strength under mildly acidic conditions and that these are propagated to the chromophore resulting in fluorescence quenching.

  16. Cannabinoid modulation of chronic mild stress-induced selective enhancement of trace fear conditioning in adolescent rats.

    PubMed

    Reich, Christian G; Iskander, Anthony N; Weiss, Michael S

    2013-10-01

    History of stress is considered a major risk factor for the development of major depression and posttraumatic stress disorder (PTSD). Elucidating the neurobiological mechanisms of Pavlovian fear conditioning may provide insight into the etiology of PTSD. In the current study, adolescent male Sprague-Dawley rats were exposed to 3 weeks of a chronic-mild-unpredictable stress (CMS) protocol. Immediately following the CMS, the animals were subjected to hippocampal-dependent (trace and contextual) and hippocampal-independent (delay) fear conditioning. CMS exposure enhanced trace freezing behavior compared to non-stress controls. This effect was not observed in contextual or delay conditioned animals. Given that the endocannabinoid system is negatively affected by CMS procedures, separate groups of stressed rats were administered the CB1 receptor agonist, ACEA (0.1 mg/kg), prior to trace fear conditioning or a memory-recall test. Regardless of administration time, ACEA significantly reduced freezing behavior in stressed animals. Furthermore, when administered during the first memory recall test, ACEA enhanced long-term extinction in both stress and non-stress groups. The results demonstrate that chronic unpredictable stress selectively enhances hippocampal-dependent episodic fear memories. Pathologies of the episodic memory and fear response may increase the susceptibility of developing PTSD. Reduction in fear responses via exogenous activation of the CB1 receptor suggests that a deficiency in the endocannabinoid system contributes to this pathology.

  17. CO₂ carbonation under aqueous conditions using petroleum coke combustion fly ash.

    PubMed

    González, A; Moreno, N; Navia, R

    2014-12-01

    Fly ash from petroleum coke combustion was evaluated for CO2 capture in aqueous medium. Moreover the carbonation efficiency based on different methodologies and the kinetic parameters of the process were determined. The results show that petroleum coke fly ash achieved a CO2 capture yield of 21% at the experimental conditions of 12 g L(-1), 363°K without stirring. The carbonation efficiency by petroleum coke fly ash based on reactive calcium species was within carbonation efficiencies reported by several authors. In addition, carbonation by petroleum coke fly ash follows a pseudo-second order kinetic model.

  18. A New Biarylphosphine Ligand for the Pd-Catalyzed Synthesis of Diaryl Ethers Under Mild Conditions

    PubMed Central

    Salvi, Luca; Davis, Nicole R.; Ali, Siraj Z.; Buchwald, Stephen L.

    2011-01-01

    A new bulky biarylphosphine ligand (L8) has been developed that allows the Pd-catalyzed C–O cross-coupling of a wide range of aryl halides and phenols under milder conditions than previously possible. A direct correlation between the size of the ligand substituents in the 2′, 4′ and 6′ positions of the non-phosphine containing ring and the reactivity of the derived catalyst system was observed. Specifically, the rate of coupling increased with the size of these substituents. PMID:22182186

  19. Controlled release of volatiles under mild reaction conditions: from nature to everyday products.

    PubMed

    Herrmann, Andreas

    2007-01-01

    Volatile organic compounds serve in nature as semiochemicals for communication between species, and are often used as flavors and fragrances in our everyday life. The quite limited longevity of olfactive perception has led to the development of pro-perfumes or pro-fragrances--ideally nonvolatile and odorless fragrance precursors which release the active volatiles by bond cleavage. Only a limited amount of reaction conditions, such as hydrolysis, temperature changes, as well as the action of light, oxygen, enzymes, or microorganisms, can be used to liberate the many different chemical functionalities. This Review describes the controlled chemical release of fragrances and discusses additional challenges such as precursor stability during product storage as well as some aspects concerning toxicity and biodegradability. As the same systems can be applied in different areas of research, the scope of this Review covers fragrance delivery as well as the controlled release of volatiles in general.

  20. Effects of mild TBI from repeated blast overpressure on the expression and extinction of conditioned fear in rats.

    PubMed

    Genovese, R F; Simmons, L P; Ahlers, S T; Maudlin-Jeronimo, E; Dave, J R; Boutte, A M

    2013-12-19

    Mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD) are pressing medical issues for the Warfighter. Symptoms of mTBI can overlap with those of PTSD, suggesting the possibility of a causal or mediating role of mTBI in PTSD. To address whether mTBI can exacerbate the neurobiological processes associated with traumatic stress, we evaluated the impact of mTBI from a blast overpressure (BOP) on the expression of a conditioned fear. In the rat, conditioned fear models are used to evaluate the emotional conditioning processes that are known to become dysfunctional in PTSD. Rats were first trained on a variable interval (VI), food maintained, operant conditioning task that established a general measure of performance. Inescapable electric shock (IES) was paired with an audio-visual conditioned stimulus (CS) and followed 1day later by three daily exposures to BOP (75kPa). Subsequently, the CS alone was presented once every 7days for 2months, beginning 4days following the last BOP. The CS was presented during the VI sessions allowing a concurrent measure of performance. Treatment groups (n=10, each group) received IES+BOP, IES+sham-BOP, sham-IES+BOP or sham-IES+sham-BOP. As expected, pairing the CS with IES produced a robust conditioned fear that was quantified by a suppression of responding on the VI. BOP significantly decreased the expression of the conditioned fear. No systematic short- or long-term performance deficits were observed on the VI from BOP. These results show that mTBI from BOP can affect the expression of a conditioned fear and suggests that BOP caused a decrease in inhibitory behavioral control. Continued presentation of the CS produced progressively less response suppression in both fear conditioned treatments, consistent with extinction of the conditioned fear. Taken together, these results show that mTBI from BOP can affect the expression of a conditioned fear but not necessarily in a manner that increases the conditioned fear or

  1. Electrocatalytic Hydrogenation of Oxygenates using Earth-Abundant Transition-Metal Nanoparticles under Mild Conditions.

    PubMed

    Carroll, Kyler J; Burger, Thomas; Langenegger, Lukas; Chavez, Steven; Hunt, Sean T; Román-Leshkov, Yuriy; Brushett, Fikile R

    2016-08-01

    Electrocatalytic hydrogenation (ECH) is a sustainable pathway for the synthesis of value-added organic compounds, provided affordable catalysts with high activity, selectivity and durability are developed. Here, we synthesize Cu/C, Ni/C, and CuNi/C nanoparticles and compare their performance to Pt/C, Ru/C, PtRu/C for the ECH of hydroxyacetone, a bio-derived feedstock surrogate containing a carbonyl and a hydroxyl functional group. The non-precious metal electrocatalysts show promising conversion-time behavior, product selectivities, and Faradaic efficiencies. Ni/C forms propylene glycol with a selectivity of 89 % (at 80 % conversion), while Cu/C catalyzes ECH (52 % selectivity) and hydrodeoxygenation (HDO, 48 % selectivity, accounting for evaporation). CuNi/C shows increased turnover frequencies but reduced ECH selectivity (80 % at 80 % conversion) as compared to the Ni/C catalyst. Importantly, stability studies show that the non-precious metal catalysts do not leach at operating conditions. PMID:27337680

  2. On hematite as a target for dating aqueous conditions on Mars

    NASA Astrophysics Data System (ADS)

    Kula, Joseph; Baldwin, Suzanne L.

    2012-07-01

    Hematite spherules, identified by the Opportunity Mars Exploration Rover (MER), have been interpreted as in situ evidence for past aqueous conditions on the Martian surface. Hematite has also been demonstrated as a reliable (U-Th)/He chronometer, although it is not widely used. In the absence of post-formational diffusive He loss, (U-Th)/He ages measured from Martian hematite spherules should yield the time since water was present on Mars. Using published morphologic constraints and He diffusion kinetics for hematite we model He diffusive loss to assess whether Martian hematite spherules will retain original (U-Th)/He ages during long residence times (4.0 Ga) at surface conditions (22 °C). Fractional loss calculations predict <2% diffusive loss at 22 °C over 4.0 Ga, indicating Martian hematite will preserve ages within analytical precision of the (U-Th)/He technique. If present Mars conditions persisted since the Noachian (e.g. 4.0 Ga), hematite spherules likely record ages reflecting the timing of aqueous mineralization. For the 'wetting-upwards' Burn Formation at Meridiani Planum, hematite from the lower eolian dune subunit would be postdepositional providing a minimum age on deposition, while hematite from the upper interdune/playa unit may be syndepositional thus yielding the age of the deposit. Therefore (U-Th)/He hematite ages obtained from samples collected along a vertical profile could potentially constrain the timing and rates of water saturation of the rock column, and the timing of the transition from wet to dry conditions at Meridiani Planum. Determining an absolute paleohydrologic timescale on Mars may reveal if water was available for sufficient durations required for the development of life.

  3. Semiconducting polymer encapsulated mesoporous silica particles with conjugated Europium complexes: toward enhanced luminescence under aqueous conditions.

    PubMed

    Zhang, Jixi; Prabhakar, Neeraj; Näreoja, Tuomas; Rosenholm, Jessica M

    2014-01-01

    Immobilization of lanthanide organic complexes in meso-organized hybrid materials for luminescence applications have attracted immense interest due to the possibility of controlled segregation at the nanoscopic level for novel optical properties. Aimed at enhancing the luminescence intensity and stability of the hybrid materials in aqueous media, we developed polyvinylpyrrolidone (PVP) stabilized, semiconducting polymer (poly(9-vinylcarbazole), PVK) encapsulated mesoporous silica hybrid particles grafted with Europium(III) complexes. Monosilylated β-diketonate ligands (1-(2-naphthoyl)-3,3,3-trifluoroacetonate, NTA) were first co-condensed in the mesoporous silica particles as pendent groups for bridging and anchoring the lanthanide complexes, resulting in particles with an mean diameter of ∼ 450 nm and a bimodal pore size distribution centered at 3.5 and 5.3 nm. PVK was encapsulated on the resulted particles by a solvent-induced surface precipitation process, in order to seal the mesopores and protect Europium ions from luminescence quenching by producing a hydrophobic environment. The obtained polymer encapsulated MSN-EuLC@PVK-PVP particles exhibit significantly higher intrinsic quantum yield (Φ(Ln) = 39%) and longer lifetime (τ(obs) = 0.51 ms), as compared with those without polymer encapsulation. Most importantly, a high luminescence stability was realized when MSN-EuLC@PVK-PVP particles were dispersed in various aqueous media, showing no noticeable quenching effect. The beneficial features and positive attributes of both mesoporous silica and semiconducting polymers as lanthanide-complex host were merged in a single hybrid carrier, opening up the possibility of using these hybrid luminescent materials under complex aqueous conditions such as biological/physiological environments.

  4. Corrosion detection of mild steel in a two phase hydrocarbon-electrolyte system under flow conditions using electrochemical noise

    SciTech Connect

    Male, J.M.; Uruchurtu, J.; Coron, O.

    1998-12-31

    Electrochemical current noise (ECN) measurements were carried out in mixtures of 3% NaCl electrolyte in diesel under stirred conditions (0 to 2,000 rpm) using a Rotating Electrodes System (RES) which includes three mild steel concentric electrodes embedded in activated polyester resin. Chemical activation of the resin allowed electrochemical measurements in the water in oil emulsion system. A 0.2 to 15% in volume range of 3% NaCl electrolyte additions was studied. Three distinctive noise patterns were obtained from electrochemical current noise (ECN) time-series: (a) a low noise baseline for diesel in absence of electrolyte, diesel with small additions of electrolyte and/or low flow rates, (b) a low noise signal with current bursts superimposed obtained from relatively small additions of electrolyte and high rotation rates and (c) a high amplitude signal for high rotation rates and relatively high additions of electrolyte. For case b, the number and intensity of current bursts is indicative of proximity to cases a or c. These results contrast with experiments carried out with a conventional non-activated resin which is insensitive to the range of electrolyte additions or to stirring conditions. This method can be implemented for water in oil systems where early corrosion detection is desirable.

  5. Alcohol‐Selective Oxidation in Water under Mild Conditions via a Novel Approach to Hybrid Composite Photocatalysts

    PubMed Central

    Abd‐Elaal, Ali; Ciriminna, Rosaria; Loddo, Vittorio

    2015-01-01

    Abstract The oxidation of alcohols to carbonyl compounds in a clean fashion (i.e., with water as a solvent or under solvent‐free conditions, and using O2 or H2O2 as the primary oxidant) is the subject of considerable research efforts. A new approach for the selective oxidation of soluble aromatic alcohols in water under mild conditions via a novel composite photocatalyst has been developed. The catalyst is synthesized by grafting 4‐(4‐(4‐hydroxyphenylimino)cyclohexa‐2,5dienylideneamino)phenol and silver nanoparticles onto the surface of moderately crystalline titanium dioxide. The titanium dioxide‐based composite was first extensively characterized and then employed in the catalytic oxidation of 4‐methoxybenzyl alcohol to 4‐methoxybenzaldehyde under UV irradiation in water at room temperature. The corresponding aldehyde was obtained with unprecedented high selectivity (up to 86 %). The method is general and opens the route to fabrication of photocatalytic composites based on titanium dioxide functionalized with shuttle organic molecules and metal nanoparticles for a variety of oxidative conversions. PMID:27308204

  6. Superoxide radical scavenging by phenolic bronchodilators under aprotic and aqueous conditions.

    PubMed

    Zwicker, K; Damerau, W; Dikalov, S; Scholtyssek, H; Schimke, I; Zimmer, G

    1998-08-01

    Asthmatic airway disease is accompanied by the appearance of inflammatory cells which produce reactive oxygen species (ROS). Therefore, the radical scavenging properties of the bronchodilators reproterol, fenoterol, salbutamol and terbutaline toward superoxide anion radicals and hydroperoxyl radicals were investigated in a model system by electron paramagnetic resonance spectroscopy (EPR) and photometric approaches. The substances under study showed activity in superoxide radical scavenging under aprotic and protic conditions as well. The efficiency of the reaction decreased in the order: fenoterol > salbutamol > reproterol > terbutaline > oxyfedrine when DMSO was used as an aprotic solvent. In an aqueous system, the rate constants decreased in the order: fenoterol > reproterol > salbutamol. It is suggested that the antioxidant effect of these beta2-agonists is an additional advantage in treatment of asthmatic lung disease, reducing the negative consequences of airway inflammation. PMID:9744566

  7. Cementation and Aqueous Alteration of a Sandstone Unit Under Acidic Conditions in Gale Crater, Mars

    NASA Technical Reports Server (NTRS)

    Yen, A. S.; Blake, D. F.; Ming, D. W.; Morris, R. V.; Gellert, R.; Clark, B.; Vaniman, D. T.; Chipera, S. J.; Thompson, L. M.; Bristow, T. F.; Rampe, E. B.; Crisp, J. A.

    2016-01-01

    The Curiosity rover landed on Mars in August 2012 to explore the sedimentary history and to assess the habitability of Gale Crater. After 1200 sols of surface operations and over 12 km of traverse distance, the mineralogy of 10 samples has been determined by the CheMin X-ray diffractometer (XRD) and the chemical composition of nearly 300 targets has been established by the Alpha Particle X-ray Spectrometer (APXS). Light-toned fracture zones containing elevated concentrations of silica have been studied by Curiosity's instruments to determine the nature of the fluids that resulted in the enrichment of SiO2. Multiple fluid exposures are evident, and the chemistry and mineralogy data indicate at least two aqueous episodes may have occurred under acidic conditions.

  8. Aqueous Dissolution of Silver Iodide and Associated Iodine Release Under Reducing Conditions with Sulfide

    SciTech Connect

    Yaohiro Inagaki; Toshitaka Imamura; Kazuya Idemitsu; Tatsumi Arima; Osamu Kato; Hidekazu Asano; Tsutomu Nishimura

    2007-07-01

    Aqueous dissolution tests of silver iodide (AgI) were performed in Na{sub 2}S solutions in order to evaluate, empirically, dissolution of AgI to release iodine under reducing conditions with sulfide. The results indicated that AgI dissolves to release iodine being controlled by mainly precipitation of Ag{sub 2}S. However, the dissolution of AgI can be depressed to proceed, and the thermodynamic equilibrium cannot be attained easily. Solid phase analysis for the reacted AgI suggested that a thin layer of solid silver forming at AgI surface may evolve to be protective against transportation of reactant species, which can lead to the depression in the dissolution of AgI. (authors)

  9. Anticompulsive Activity of a New Pyrazolo[C]Pyridine Derivative GIZh-72 under Conditions of Unpredictable Chronic Mild Stress.

    PubMed

    Kudryashov, N V; Kalinina, T S; Zhmurenko, L A; Voronina, T A

    2016-07-01

    Anticompulsive activity of a novel compound GIZh-72 (4,6-dimethyl-2-(4-chlorphenyl)-2,3-dihydro-1H-pyrazolo[4,3-C]Pyridine-3-on, chloral hydrate) in a dose of 20 mg/kg (single, subchronic, and chronic administration) in comparison with fluvoxamine (25 mg/kg) was studied in the marble burying test in the model of unpredictable chronic mild stress on BALB/c mice. GIZh-72 produced an anticompulsive effect that increased with increasing treatment duration under stress conditions in contrast to fluvoxamine that induced inversion of this effect after long-term administration. Neuroleptic activity of GIZh-72 in doses of 20 and 40 mg/kg was studied on the model of apomorphine-induced climbing in C57Bl/6 mice. In contrast to haloperidol (0.5 mg/kg), GIZh-72 exhibited no neuroleptic properties. Our results indicate that GIZh-72 holds much promise for pharmacotherapy of obsessive-compulsive disorder. PMID:27502699

  10. Synthesis of cellulose triacetate from cotton cellulose by using NIS as a catalyst under mild reaction conditions.

    PubMed

    El Nemr, Ahmed; Ragab, Safaa; El Sikaily, Amany; Khaled, Azza

    2015-10-01

    This research discusses the acetylation of cotton cellulose with acetic anhydride without solvents. The acetylation was done in the presence of different amounts of N-Iodosuccinimide (NIS) as a catalyst; this took place under mild reaction conditions. The extent of acetylation was measured by the weight percent gain (WPG) that varied from 24.71 to 71.83%. Cotton cellulose acetates, with the degree of substitution (DS) that ranged from 0.89 to 2.84, were prepared in one step. The cellulose triacetate, with a degree of substitution (DS) 2.84, was obtained. The WPG and DS were easily controlled by changing the reaction duration (1-5h), and the concentration of the catalyst (0.05 g, 0.075 g and 0.10 g for 1g of cellulose) in 25 ml of acetic anhydride. NIS was recognized as a novel and more successful catalyst for the acetylation of hydroxyl groups in cotton cellulose. Formation of the acetates and the calculation of the degree of substitution were performed by FT-IR, Raman, and (1)H NMR.

  11. The Formation of Seven-Membered Heterocycles under Mild Pictet-Spengler Conditions: A Route to Pyrazolo[3,4]benzodiazepines.

    PubMed

    Katte, Timothy A; Reekie, Tristan A; Jorgensen, William T; Kassiou, Michael

    2016-06-01

    Reported is a method for the synthesis of seven-membered heterocycles via a Pictet-Spengler condensation reaction under very mild conditions. High substrate scope allows for use of aldehydes using catalytic amounts of acetic acid yielding 39-90% and ketones using catalytic amounts of trifluoroacetic acid yielding 25-83%. PMID:27159074

  12. Measurement of interaction forces between lignin and cellulose as a function of aqueous electrolyte solution conditions.

    PubMed

    Notley, Shannon M; Norgren, Magnus

    2006-12-19

    The interaction between a lignin film and a cellulose sphere has been measured using the colloidal probe force technique as a function of aqueous electrolyte solution conditions. The lignin film was first studied for its roughness and stability using atomic force microscopy imaging and quartz crystal microbalance measurements, respectively. The film was found to be smooth and stable in the pH range of 3.5-9 and in ionic strengths up to and including 0.01 M. This range of ionic strength and pH was hence used to measure the surface force profiles between lignin and cellulose. Under these solution conditions, the measured forces behaved according to DLVO theory. The force-distance curves could be fitted between the limits of constant charge and constant potential, and the surface potential of the lignin films was determined as a function of pH. At a pH greater than 9.5, a short range steric repulsion was observed, indicating that the film was swelling to a large extent but did not dissolve. Thus, lignin films prepared in this manner are suitable for a range of surface force studies.

  13. Human Serum Albumin Increases the Stability of Green Tea Catechins in Aqueous Physiological Conditions.

    PubMed

    Zinellu, Angelo; Sotgia, Salvatore; Scanu, Bastianina; Forteschi, Mauro; Giordo, Roberta; Cossu, Annalisa; Posadino, Anna Maria; Carru, Ciriaco; Pintus, Gianfranco

    2015-01-01

    Epicatechin (EC), epigallocatechin (EGC), epicatechingallate (ECG) and epigallocatechingallate (EGCG) are antioxidants present in the green tea, a widely used beverage whose health benefits are largely recognized. Nevertheless, major physicochemical limitations, such as the high instability of catechins, pose important questions concerning their potential pharmacological use. Recent studies indicate that binding of catechins with plasmatic proteins may modulate their plasma concentration, tissue delivery and biological activity. After 5 minutes of incubation with HSA both ECG and EGCG were fully bound to HSA, while after 48h incubation only 41% of EC and 70% of EGC resulted linked. HSA had a strong stabilizing effect on all catechins, which could be found in solution between 29 and 85% even after 48h of incubation. In the absence of HSA, EGC and EGCG disappeared in less than 24h, while ECG and EC were found after 48h at 5 and 50%, respectively. The stabilizing effect of HSA toward EGCG, obtained in aqueous physiological conditions, resulted stronger in comparison to cysteine and HCl, previously reported to stabilize this polyphenol. Because of the multitude of contradictory data concerning in vivo and in vitro antioxidant-based experimentations, we believe our work may shed some light on this debated field of research. PMID:26230943

  14. Hybrid palm-oil/styrene-maleimide nanoparticles synthesized in aqueous dispersion under different conditions.

    PubMed

    Samyn, Pieter; Van Nieuwkerke, Dieter; Schoukens, Gustaaf; Stanssens, Dirk; Vonck, Leo; Van den Abbeele, Henk

    2015-01-01

    Poly(styrene-co-maleic anhydride) was imidized with ammonium hydroxide and palm oil, resulting in an aqueous dispersion of hybrid nanoparticles with diameters 85-180 nm (dispersed) or 20-50 nm (dried). The reaction conditions were optimized for different precursors by evaluating the relative amount ammonium hydroxide and maximizing the incorporated palm oil up to 70 wt.%. The interactions between palm oil and polymer phase have been studied by TEM, IR, Raman spectroscopy and thermal analysis (TGA, [TM] DSC). From Raman spectra, the amount of imide and reacted oil were quantified. Through concurring effects of imidization and coupling of fatty acids, the imidization needs a slight excess of NH3 relatively to maleic anhydride. The oxidative stability highly depends on oxidative crosslinking of free or non-reacted oil. Comparing the imide content from spectroscopic and thermal analysis suggests that a complex rigid imide phase without strong relaxation behavior has formed in combination with oil.

  15. The management of burns under conditions of limited resources using topical aqueous sulfamylon (mafenide) hydrochloride spray.

    PubMed

    Mendelson, J A

    1997-01-01

    The burn unit establishment in a Vietnamese military hospital (1970 to 1971) is an example of the management of burns under conditions of limited resources. The problems encountered and methods used in their solution are still relevant. This is the first (and possibly still the only) instance of such clinical use of topical Sulfamylon (mafenide) aqueous spray as the sole pregraft antibacterial agent for patients with deep partial-thickness and full-thickness burns (and associated injuries). The mafenide spray open treatment resulted in a bacteriostatic film permitting eschars to remain uninfected while more superficial burns healed and general status improved, enabling delayed grafting to be effective. Use of operating rooms, supplies, and personnel was minimized. The study group contained 211 patients; 86 (approximately 40%) had burns that exceeded 20% body surface area, and 26 (approximately 12%) had burns that exceeded 40% body surface area. As the procedures became fully established, all of the last 110 patients of this series survived. Only 17 deaths occurred in the total series; none were attributed to infection.

  16. Radiolysis of pyridoxine (vitamin B 6) in aqueous solution under different conditions

    NASA Astrophysics Data System (ADS)

    Albarrán, Guadalupe; Ramírez-Cahero, Fernando; Aliev, Roustam

    2008-05-01

    Aqueous solutions of pyridoxine (1 mM) without or with additive of K 3[Fe(CN) 6] (2.5 mM) were gamma-irradiated at different doses and dose rate of 2.16 kGy/h in the absence of air, in the presence of air or by their saturation with N 2O. The radiolytic products were analyzed with HPLC, mass spectrometry and UV spectroscopy. 2,4,5-Trihydroxymethyl-3-pyridinol, pyridoxal, isopyridoxal and 6-hydroxypyridoxine were formed by radiolysis in the absence of K 3[Fe(CN) 6], and their concentrations were much higher in samples saturated with N 2O. Pyridoxi-3,6-quinone was found by radiolysis under all the above-mentioned conditions but only in the presence of K 3[Fe(CN) 6]. Besides, the pyridoxal formation increased in the presence of this oxidizing agent. G values of pyridoxal formation and pyridoxine degradation were quantified. Some details of the radiolytic product formation were discussed.

  17. [Cu(OH)(TMEDA)]₂Cl₂-catalyzed regioselective 2-arylation of 5-substituted tetrazoles with boronic acids under mild conditions.

    PubMed

    Onaka, Takuya; Umemoto, Hideaki; Miki, Yasuyoshi; Nakamura, Akira; Maegawa, Tomohiro

    2014-07-18

    A mild and regioselective 2-arylation of 5-substituted tetrazoles is described. The reaction proceeds regioselectively with a variety of arylboronic acids in the presence of [Cu(OH)(TMEDA)]2Cl2 to afford 2,5-disubstituted tetrazoles. This is the first report of highly regioselective arylation of 5-alkyltetrazoles. PMID:24962401

  18. Mutagenic effect by phenylalanine during gamma-irradiation of plasmid DNA in aqueous solution under oxic conditions.

    PubMed

    Reitsma-Wijker, C A; Slotman, B J; Lafleur, M V

    2000-11-01

    Irradiation of DNA in aqueous solution or in cells with gamma-rays results in different mutational spectra, indicating that in both situations different patterns of DNA damages are induced. One of the causes for these different types of damages might be the formation of secondary, organic radicals, if cells are irradiated. Some organic compounds, including the amino acid phenylalanine, are well known to produce radicals during irradiation. Under oxic conditions these secondary radicals react with oxygen, thus forming peroxyl radicals which can be very harmful to DNA, and which may, therefore, induce DNA damage leading to mutations. This study examines the influence of the presence of phenylalanine during gamma-irradiation of DNA in aqueous solution under oxic conditions. The results indicate that the formation of phenylalanine radicals influences the types of induced mutations in the gamma-radiation-induced mutation spectrum. The most prominent difference is the increase in G:C to T:A transversions and the decrease in G:C to A:T transitions in the presence of phenylalanine. Further, it appears that the gamma-radiation-induced mutation spectrum after irradiation of DNA in aqueous solution is more comparable to the intracellular gamma-radiation-induced mutation spectrum in E. coli cells, if phenylalanine is present during irradiation. Therefore, these results suggest that the presence of phenylalanine during irradiation of DNA in aqueous solution gives a better impression of gamma-radiation-induced mutations in bacterial systems than water only. PMID:11035161

  19. Experimental aqueous alteration of the Allende meteorite under oxidizing conditions: Constraints on asteroidal alteration

    NASA Astrophysics Data System (ADS)

    Jones, Catherine L.; Brearley, Adrian J.

    2006-02-01

    We have performed an experimental study of the aqueous alteration of the Allende CV3 carbonaceous chondrite under highly oxidizing conditions, in order to examine the alteration behavior of Allende's anhydrous mineralogy. The experiments were carried out at temperatures of 100, 150, and 200 °C, for time periods between 7 and 180 days, with water/rock ratios ranging from 1:1 to 9:1. Uncrushed cubes of Allende were used so that the spatial relationships between reactant and product phases could be examined in detail. Scanning electron microscope studies show that in all the experiments, even those of short duration (7 days), soluble salts of Ca and Mg (CaSO 4, CaCO 3, and MgSO 4) precipitated on the sample surface, indicating that these elements are rapidly mobilized during alteration. In addition, iron oxides and hydroxides formed on the sample surfaces. The sulfates, carbonates, and the majority of the iron-bearing secondary minerals are randomly distributed over the surface of samples. In some instances the iron oxides and hydroxides are constrained to the boundaries of altering mineral grains. Transmission electron microscope studies show that the FeO-rich olivine in the interior of the samples has altered to form interlayered serpentine/saponite and Fe-oxyhydroxides. The degree of alteration increases significantly with increasing water/rock ratio, and to a lesser extent with increasing duration of heating. The serpentine/saponite forms both by direct replacement of the olivine in crystallographically oriented intergrowths, and by recrystallization of an amorphous Si-rich phase that precipitates in pore space between the olivine grains. The alteration assemblage bears many similarities to those found in altered carbonaceous chondrites, although in detail there are important differences, which we attribute to (a) the relatively high temperatures of our experiments and (b) comparatively short reaction times compared with the natural examples. In terms of mineral

  20. The distribution of methane in groundwater in Alberta (Canada) and associated aqueous geochemistry conditions

    NASA Astrophysics Data System (ADS)

    Humez, Pauline; Mayer, Bernhard; Nightingale, Michael; Becker, Veith; Kingston, Andrew; Taylor, Stephen; Millot, Romain; Kloppmann, Wolfram

    2016-04-01

    Development of unconventional energy resources such as shale gas and coalbed methane has generated some public concern with regard to the protection of groundwater and surface water resources from leakage of stray gas from the deep subsurface. In terms of environmental impact to and risk assessment of shallow groundwater resources, the ultimate challenge is to distinguish: (a) natural in-situ production of biogenic methane, (b) biogenic or thermogenic methane migration into shallow aquifers due to natural causes, and (c) thermogenic methane migration from deep sources due to human activities associated with the exploitation of conventional or unconventional oil and gas resources. We have conducted a NSERC-ANR co-funded baseline study investigating the occurrence of methane in shallow groundwater of Alberta (Canada), a province with a long record of conventional and unconventional hydrocarbon exploration. Our objective was to assess the occurrence and sources of methane in shallow groundwaters and to also characterize the hydrochemical environment in which the methane was formed or transformed through redox processes. Ultimately our aim was to determine whether methane was formed in-situ or whether it migrated from deeper formations into shallow aquifers. Combining hydrochemical and dissolved and free geochemical gas data from 372 groundwater samples obtained from 186 monitoring wells of the provincial groundwater observation well network (GOWN) in Alberta, it was found that methane is ubiquitous in groundwater in Alberta and is predominantly of biogenic origin. The highest concentrations of dissolved biogenic methane (> 0.01 mM or > 0.2 mg/L), characterized by δ13CCH4 values < -55‰, occurred in anoxic Na-Cl, Na-HCO3 and Na-HCO3-Cl type groundwater with negligible concentrations of nitrate and sulfate suggesting that methane was formed in-situ under methanogenic conditions consistent with the redox ladder concept. Despite quite variable gas concentrations and a

  1. Complexes of earth-abundant metals for catalytic electrochemical hydrogen generation under aqueous conditions.

    PubMed

    Thoi, V Sara; Sun, Yujie; Long, Jeffrey R; Chang, Christopher J

    2013-03-21

    Growing global energy demands and climate change motivate the development of new renewable energy technologies. In this context, water splitting using sustainable energy sources has emerged as an attractive process for carbon-neutral fuel cycles. A key scientific challenge to achieving this overall goal is the invention of new catalysts for the reductive and oxidative conversions of water to hydrogen and oxygen, respectively. This review article will highlight progress in molecular electrochemical approaches for catalytic reduction of protons to hydrogen, focusing on complexes of earth-abundant metals that can function in pure aqueous or mixed aqueous-organic media. The use of water as a reaction medium has dual benefits of maintaining high substrate concentration as well as minimizing the environmental impact from organic additives and by-products.

  2. Immiscible Hydrocarbon and Aqueous Fluids Under Subduction Zone Conditions and Implications for the Deep Carbon Cycle

    NASA Astrophysics Data System (ADS)

    Huang, F.; Daniel, I.; Cardon, H.; Montagnac, G.; Sverjensky, D. A.

    2015-12-01

    Subducting slabs recycle rocks into the deep Earth releasing fluids which may cause partial melting and possible oxidation of the mantle wedge. Recent theoretical studies1 indicate that at pressures greater than about 3.0 GPa these fluids could contain high concentrations of organic and inorganic C-species with a wide range of C-oxidation states at equilibrium. If so, such fluids could play an important role in the deep carbon cycle, including the formation of diamond. However, direct experimental observations of the speciation in the fluids are needed. We studied 1.0 M aqueous Na-formate and 1.0 M Na-acetate solutions in the diamond anvil cell using Raman spectroscopy at 300 ºC and 3.0 GPa for up to 60 hours. Our preliminary results indicate that formate rapidly decomposed to bicarbonate/carbonate species and methane, with no detectable H2. Acetate decomposed much more slowly. Within the first two hours of heating, crystals of Na2CO3 precipitated in the fluid, and kept growing while immiscible droplets of hydrocarbon appeared and persisted throughout the experiments at elevated temperature and pressure. In the aqueous fluid, acetate and HCO3- were present during the first 6 hours, and then CO32- and acetate after 20 hours of heating. The final HCO3- /CO32- ratio was constant indicating a constant pH. This is the first in situ observation of persistent immiscible fluid hydrocarbons formed from an aqueous precursor at upper mantle pressures. Our results suggest that Earth's subduction zone fluids at high pressures might involve fluid hydrocarbon species as well as inorganic and organic aqueous C-species, which considerably broadens the picture of deep carbon sources, cycles and sinks. [1] Sverjensky et at. (2014), Nat. Geosci. 7, 909-913.

  3. Effect of condensation agents and minerals for oligopeptide formation under mild and hydrothermal conditions in related to chemical evolution of proteins

    NASA Astrophysics Data System (ADS)

    Kawamura, Kunio; Takeya, Hitoshi; Kushibe, Takao

    2009-07-01

    The role of condensation agents and minerals for oligopeptide formation was inspected to see whether minerals possess catalytic activity under mild and hydrothermal conditions. Under mild conditions, oligopeptide formation from negatively charged amino acids (Asp and Glu) using different minerals and the elongation of alanine oligopeptides ((Ala) 2-(Ala) 5) were attempted using apatite minerals. Oligo(Asp) up to 10 amino acid units from Asp were observed in the presence of 1-ethyl-3-(3-dimethylaminopropyl carbodiimide (EDC). Notable influence of minerals was not detected for the oligo(Asp) formation. Oligo(Asp) was gradually degraded by the further incubation in the presence of EDC in both the absence and presence of minerals. The formation of oligo(Glu) was less efficient in the presence of carbonyldiimidazole. The elongation from (Ala) 3, (Ala) 4, and (Ala) 5 and the formation of diketopiperazine from (Ala) 2 proceeded immediately in the presence of EDC in the meantime of the sample preparations. In addition, it was unexpected that the disappearance of the products and the reformation of the reactants occurred by the further incubation for 24 h; for instance, (Ala) 5 decreased but (Ala) 4 increased with increasing the reaction time in the reaction of (Ala) 4 with EDC. These facts suggest that the activation of the reactant amino acids or peptides immediately occurs. Under the simulated hydrothermal conditions, EDC did not enhance the formation of oligopeptides from Asp, Glu or Ala nor the spontaneous formation of (Ala) 5 from (Ala) 4.

  4. A ketone/alcohol polymer for cycle of electrolytic hydrogen-fixing with water and releasing under mild conditions

    NASA Astrophysics Data System (ADS)

    Kato, Ryo; Yoshimasa, Keisuke; Egashira, Tatsuya; Oya, Takahiro; Oyaizu, Kenichi; Nishide, Hiroyuki

    2016-09-01

    Finding a safe and efficient carrier of hydrogen is a major challenge. Recently, hydrogenated organic compounds have been studied as hydrogen storage materials because of their ability to stably and reversibly store hydrogen by forming chemical bonds; however, these compounds often suffer from safety issues and are usually hydrogenated with hydrogen at high pressure and/or temperature. Here we present a ketone (fluorenone) polymer that can be moulded as a plastic sheet and fixes hydrogen via a simple electrolytic hydrogenation at -1.5 V (versus Ag/AgCl) in water at room temperature. The hydrogenated alcohol derivative (the fluorenol polymer) reversibly releases hydrogen by heating (80 °C) in the presence of an aqueous iridium catalyst. Both the use of a ketone polymer and the efficient hydrogen fixing with water as a proton source are completely different from other (de)hydrogenated compounds and hydrogenation processes. The easy handling and mouldable polymers could suggest a pocketable hydrogen carrier.

  5. Delamination of layered zeolite precursors under mild conditions: synthesis of UCB-1 via fluoride/chloride anion-promoted exfoliation.

    PubMed

    Ogino, Isao; Nigra, Michael M; Hwang, Son-Jong; Ha, Jeong-Myeong; Rea, Thomas; Zones, Stacey I; Katz, Alexander

    2011-03-16

    New material UCB-1 is synthesized via the delamination of zeolite precursor MCM-22 (P) at pH 9 using an aqueous solution of cetyltrimethylammonium bromide, tetrabutylammonium fluoride, and tetrabutylammonium chloride at 353 K. Characterization by powder X-ray diffraction, transmission electron microscopy, and nitrogen physisorption at 77 K indicates the same degree of delamination in UCB-1 as previously reported for delaminated zeolite precursors, which require a pH of greater than 13.5 and sonication in order to achieve exfoliation. UCB-1 consists of a high degree of structural integrity via (29)Si MAS NMR and Fourier transform infrared spectroscopies, and no detectable formation of amorphous silica phase via transmission electron microscopy. Porosimetry measurements demonstrate a lack of hysteresis in the N(2) adsorption/desorption isotherms and macroporosity in UCB-1. The new method is generalizable to a variety of Si:Al ratios and leads to delaminated zeolite precursor materials lacking amorphization. PMID:21341663

  6. A predictive model for the influence of food components on survival of Listeria monocytogenes LM 54004 under high hydrostatic pressure and mild heat conditions.

    PubMed

    Gao, Yu-Long; Ju, Xing-Rong; Wu-Ding

    2007-07-15

    The combination of high hydrostatic pressure with mild temperature was explored to achieve a predictive model of microbial inactivation in food matrix processing. The pressure processing conditions were fixed at 448 MPa for 11 min at the treatment temperature of 41 degrees C, which have been determined as the optimum processing conditions considering six log-cycle reductions of Listeria monocytogenes. Based on the results, response surface methodology (RSM) was performed in the present work, the influence of food components like soybean protein (0-5.00%), sucrose (0.25-13.25%), bean oil (0-10.00%), and pH (4-10) of the food matrix on survival of L. monocytogenes by high pressure and mild heat was studied, and a quadratic predictive model for the influence of food components and pH of food matrix on L. monocytogenes reduction by high pressure and mild heat was built with RSM accurately. The experimental results showed that the efficiency of L. monocytogenes reduction in milk buffer and food matrix designed in the present work, under the HPP treatment process parameters described above, were different. The soybean protein (P=0.0086), sucrose (P<0.0001), and pH (P=0.0136) significantly affected reduction of L. monocytogenes, but the effect of bean oil on reduction of L. monocytogenes was not significant (P=0.1028). The predictive model is significant since the level of significance was P<0.0001 and the calculated F value (11.53) is much greater than the tabulated F value (F(0.01 (14, 5))=9.77). Moreover, the adequacy of the predictive model equation for predicting the level of L. monocytogenes reduction was verified effectively by the validation data.

  7. The effect of precipitation conditions and aging upon characteristics of particles precipitated from aqueous solutions

    SciTech Connect

    Rard, J.A.

    1989-10-01

    Precipitation of a dissolved species from aqueous solutions is one of the techniques used to grow particles with certain size or composition characteristics. Various factors affecting the particle properties for sparingly soluble substances are briefly discussed here, including homogeneous versus heterogeneous nucleation, the effect of relative supersaturation on the number of nuclei and their relative size, particle growth by way of Ostwald Ripening, the Ostwald Step Rule and nucleation of metastable phases, diffusion-controlled versus surface reaction-controlled growth, incorporation of dopants into the precipitate, and dendritic growth. 13 refs.

  8. Dissolution of Columbia River Basalt Under Mildly Acidic Conditions as a Function of Temperature: Experimental Results Relevant to the Geological Sequestration of Carbon Dioxide

    SciTech Connect

    Schaef, Herbert T.; McGrail, B. Peter

    2009-05-01

    Increasing attention is being focused on the rapid rise of carbon dioxide levels in the atmosphere, which many believe to be the major contributing factor to global climate change. Sequestering CO2 in deep geological formations has been proposed as a long-term solution to help stabilize CO2 levels. However, before such technology can be developed and implemented, a basic understanding of H2O-CO2 systems and the chemical interactions of these fluids with the host formation must be obtained. Important issues concerning mineral stability, reaction rates, and carbonate formation are all controlled or at least significantly impacted by the kinetics of rock-water reactions in mildly acidic, CO2-saturated solutions. Basalt has recently been identified as a potentially important host formation for geological sequestration. Dissolution kinetics of the Columbia River Basalt (CRB) were measured for a range of temperatures (25° to 90°C) under mildly acidic to neutral pH conditions using the single-pass flow-through test method. Under anaerobic conditions, the normalized dissolution rates for CRB decrease with increasing pH (3≤pH≤7) with a slope, η, of -0.12 ± 0.02. An activation energy, Ea, has been estimated at 30.3 ± 2.4 kJ mol-1. Dissolution kinetics measurements like these are essential for modeling the rate at which the CO2 reacts with basalt and ultimately converted to carbonate minerals in situ.

  9. Superparamagnetic iron oxide coated on the surface of cellulose nanospheres for the rapid removal of textile dye under mild condition

    NASA Astrophysics Data System (ADS)

    Qin, Yunfeng; Qin, Zongyi; Liu, Yannan; Cheng, Miao; Qian, Pengfei; Wang, Qian; Zhu, Meifang

    2015-12-01

    Magnetic composite nanoparticles (MNPs) were prepared by anchoring iron oxide (Fe3O4) on the surface of carboxyl cellulose nanospheres through a facile chemical co-precipitation method. The as-prepared MNPs were characterized by atomic force microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, wide-angle X-ray diffraction measurement, thermal gravity analysis and vibrating sample magnetometry. These MNPs were of a generally spherical shape with a narrow size distribution, and exhibited superparamagnetic behaviors with high saturation magnetization. High efficient removal of Navy blue in aqueous solution was demonstrated at room temperature in a Fenton-like system containing the MNPs and H2O2, which benefited from small particle size, large surface area, high chemical activity, and good dispersibility of the MNPs. The removal efficiency of Navy blue induced by the MNPs prepared at a weight ratio of cellulose to iron of 1:2 were 90.6% at the first minute of the degradation reaction, and 98.0% for 5 min. Furthermore, these MNPs could be efficiently recycled and reused by using an external magnetic field. The approach presented in this paper promotes the use of renewable natural resources as templates for the preparation and stabilization of various inorganic nanomaterials for the purpose of catalysis, magnetic resonance imaging, biomedical and other potential applications.

  10. ROS initiated oxidation of dopamine under oxidative stress conditions in aqueous and lipidic environments.

    PubMed

    Iuga, Cristina; Alvarez-Idaboy, J Raul; Vivier-Bunge, Annik

    2011-10-27

    Dopamine is known to be an efficient antioxidant and to protect neurocytes from oxidative stress by scavenging free radicals. In this work, we have carried out a systematic quantum chemistry and computational kinetics study on the reactivity of dopamine toward hydroxyl (•OH) and hydroperoxyl (•OOH) free radicals in aqueous and lipidic simulated biological environments, within the density functional theory framework. Rate constants and branching ratios for the different paths contributing to the overall reaction, at 298 K, are reported. For the reactivity of dopamine toward hydroxyl radicals, in water at physiological pH, the main mechanism of the reaction is proposed to be the sequential electron proton transfer (SEPT), whereas in the lipidic environment, hydrogen atom transfer (HAT) and radical adduct formation (RAF) pathways contribute almost equally to the total reaction rate. In both environments, dopamine reacts with hydroxyl radicals at a rate that is diffusion-controlled. Reaction with the hydroperoxyl radical is much slower and occurs only by abstraction of any of the phenolic hydrogens. The overall rate coefficients are predicted to be 2.23 × 10(5) and 8.16 × 10(5) M(-1) s(-1), in aqueous and lipidic environment, respectively, which makes dopamine a very good •OOH, and presumably •OOR, radical scavenger. PMID:21919526

  11. ROS Initiated Oxidation of Dopamine under Oxidative Stress Conditions in Aqueous and Lipidic Environments

    PubMed Central

    2011-01-01

    Dopamine is known to be an efficient antioxidant and to protect neurocytes from oxidative stress by scavenging free radicals. In this work, we have carried out a systematic quantum chemistry and computational kinetics study on the reactivity of dopamine toward hydroxyl (•OH) and hydroperoxyl (•OOH) free radicals in aqueous and lipidic simulated biological environments, within the density functional theory framework. Rate constants and branching ratios for the different paths contributing to the overall reaction, at 298 K, are reported. For the reactivity of dopamine toward hydroxyl radicals, in water at physiological pH, the main mechanism of the reaction is proposed to be the sequential electron proton transfer (SEPT), whereas in the lipidic environment, hydrogen atom transfer (HAT) and radical adduct formation (RAF) pathways contribute almost equally to the total reaction rate. In both environments, dopamine reacts with hydroxyl radicals at a rate that is diffusion-controlled. Reaction with the hydroperoxyl radical is much slower and occurs only by abstraction of any of the phenolic hydrogens. The overall rate coefficients are predicted to be 2.23 × 105 and 8.16 × 105 M–1 s–1, in aqueous and lipidic environment, respectively, which makes dopamine a very good •OOH, and presumably •OOR, radical scavenger. PMID:21919526

  12. Guiding functional connectivity estimation by structural connectivity in MEG: an application to discrimination of conditions of mild cognitive impairment.

    PubMed

    Pineda-Pardo, José Angel; Bruña, Ricardo; Woolrich, Mark; Marcos, Alberto; Nobre, Anna C; Maestú, Fernando; Vidaurre, Diego

    2014-11-01

    Whole brain resting state connectivity is a promising biomarker that might help to obtain an early diagnosis in many neurological diseases, such as dementia. Inferring resting-state connectivity is often based on correlations, which are sensitive to indirect connections, leading to an inaccurate representation of the real backbone of the network. The precision matrix is a better representation for whole brain connectivity, as it considers only direct connections. The network structure can be estimated using the graphical lasso (GL), which achieves sparsity through l1-regularization on the precision matrix. In this paper, we propose a structural connectivity adaptive version of the GL, where weaker anatomical connections are represented as stronger penalties on the corresponding functional connections. We applied beamformer source reconstruction to the resting state MEG recordings of 81 subjects, where 29 were healthy controls, 22 were single-domain amnestic Mild Cognitive Impaired (MCI), and 30 were multiple-domain amnestic MCI. An atlas-based anatomical parcellation of 66 regions was obtained for each subject, and time series were assigned to each of the regions. The fiber densities between the regions, obtained with deterministic tractography from diffusion-weighted MRI, were used to define the anatomical connectivity. Precision matrices were obtained with the region specific time series in five different frequency bands. We compared our method with the traditional GL and a functional adaptive version of the GL, in terms of log-likelihood and classification accuracies between the three groups. We conclude that introducing an anatomical prior improves the expressivity of the model and, in most cases, leads to a better classification between groups. PMID:25111472

  13. Guiding functional connectivity estimation by structural connectivity in MEG: an application to discrimination of conditions of mild cognitive impairment

    PubMed Central

    Pineda-Pardo, José Angel; Bruña, Ricardo; Woolrich, Mark; Marcos, Alberto; Nobre, Anna C.; Maestú, Fernando; Vidaurre, Diego

    2014-01-01

    Whole brain resting state connectivity is a promising biomarker that might help to obtain an early diagnosis in many neurological diseases, such as dementia. Inferring resting-state connectivity is often based on correlations, which are sensitive to indirect connections, leading to an inaccurate representation of the real backbone of the network. The precision matrix is a better representation for whole brain connectivity, as it considers only direct connections. The network structure can be estimated using the graphical lasso (GL), which achieves sparsity through l1-regularization on the precision matrix. In this paper, we propose a structural connectivity adaptive version of the GL, where weaker anatomical connections are represented as stronger penalties on the corresponding functional connections. We applied beamformer source reconstruction to the resting state MEG recordings of 81 subjects, where 29 were healthy controls, 22 were single-domain amnestic Mild Cognitive Impaired (MCI), and 30 were multiple-domain amnestic MCI. An atlas-based anatomical parcellation of 66 regions was obtained for each subject, and time series were assigned to each of the regions. The fiber densities between the regions, obtained with deterministic tractography from diffusion-weighted MRI, were used to define the anatomical connectivity. Precision matrices were obtained with the region specific time series in five different frequency bands. We compared our method with the traditional GL and a functional adaptive version of the GL, in terms of log-likelihood and classification accuracies between the three groups. We conclude that introducing an anatomical prior improves the expressivity of the model and, in most cases, leads to a better classification between groups. PMID:25111472

  14. Transport of cerium oxide nanoparticles in saturated silica media: influences of operational parameters and aqueous chemical conditions

    PubMed Central

    Zhang, Zhaohan; Gao, Peng; Qiu, Ye; Liu, Guohong; Feng, Yujie; Wiesner, Mark

    2016-01-01

    This paper aimed to investigate the influences of operational parameters and aqueous chemical conditions on transport behaviors of cerium oxides nanoparticles (CeO2-NPs) in saturated silica media. Results indicated that increasing rates of attachment efficiency (α) were related with cationic types, and critical deposition concentration (CDC) for divalent cation (Ca2+ and Mg2+) were more than 31-fold of that for monovalent cation (Na+ and K+). Increase or reduction of electrolyte pH could both promote the mobility of CeO2-NPs in glass beads, while influence was more evident at alkaline conditions. α increased linearly with NPs concentrations, while decreased linearly with flow velocity in the column, and effects were related with electrolyte contents. Presence of surfactants could sharply decreased α, and SDS was more effective to facilitate CeO2-NPs transport than Triton X–100. With DOMs concentrations increasing, α firstly kept constant, then sharply declined, and finally reduced very slowly. The influence of DOMs on NPs deposition was in order of SA > HA > TA >  BSA. Overall, this study revealed that aqueous chemical conditions was crucial to NPs transport in porous media, and would provide significant information for our understanding on the fate and transport of nanoparticles in natural environment. PMID:27694968

  15. Transport of cerium oxide nanoparticles in saturated silica media: influences of operational parameters and aqueous chemical conditions

    NASA Astrophysics Data System (ADS)

    Zhang, Zhaohan; Gao, Peng; Qiu, Ye; Liu, Guohong; Feng, Yujie; Wiesner, Mark

    2016-10-01

    This paper aimed to investigate the influences of operational parameters and aqueous chemical conditions on transport behaviors of cerium oxides nanoparticles (CeO2-NPs) in saturated silica media. Results indicated that increasing rates of attachment efficiency (α) were related with cationic types, and critical deposition concentration (CDC) for divalent cation (Ca2+ and Mg2+) were more than 31-fold of that for monovalent cation (Na+ and K+). Increase or reduction of electrolyte pH could both promote the mobility of CeO2-NPs in glass beads, while influence was more evident at alkaline conditions. α increased linearly with NPs concentrations, while decreased linearly with flow velocity in the column, and effects were related with electrolyte contents. Presence of surfactants could sharply decreased α, and SDS was more effective to facilitate CeO2-NPs transport than Triton X–100. With DOMs concentrations increasing, α firstly kept constant, then sharply declined, and finally reduced very slowly. The influence of DOMs on NPs deposition was in order of SA > HA > TA >  BSA. Overall, this study revealed that aqueous chemical conditions was crucial to NPs transport in porous media, and would provide significant information for our understanding on the fate and transport of nanoparticles in natural environment.

  16. Composition and freezing of aqueous H2SO4/HNO3 solutions under polar stratospheric conditions

    NASA Technical Reports Server (NTRS)

    Beyer, K. D.; Seago, S. W.; Chang, H. Y.; Molina, M. J.

    1994-01-01

    The results of laboratory investigations of the freezing behavior of aqueous acid solutions indicate that in the stratosphere H2SO/H2O aerosol droplets would not freeze at temperatures above the ice frost point in the absence of HNO3; however, in the presence of typical levels of HNO3 liquid sulfuric acid aerosols take up significant amounts of HNO3 and H2O vapors and freeze much more readily. This is a consequence of the very rapid change in composition of the liquid droplets as the temperature drops to within two to three degrees of the equilibrium temperature at which HNO3 and H2O vapors would co-condense to form a liquid solution. In the high latitude stratosphere this HNO3/H2O 'dew point' is typically around 192-194 K at 100 mbar.

  17. New iridium catalysts for the selective alkylation of amines by alcohols under mild conditions and for the synthesis of quinolines by acceptor-less dehydrogenative condensation.

    PubMed

    Ruch, Susanne; Irrgang, Torsten; Kempe, Rhett

    2014-10-01

    A novel family of iridium catalysts stabilised by P,N-ligands have been introduced. The ligands are based on imidazo[1,5-b]pyridazin-7-amines and can be synthesised with a broad variety of substitution patterns. The catalysts were synthesised quantitatively from the protonated ligands and a commercially available iridium precursor. The catalysts mediate the alkylation of amines by alcohols under mild conditions (70 °C). In addition, the synthesis of quinolines from secondary or primary alcohols and amino alcohols is reported. This sustainable synthesis proceeds through the liberation of two equivalents of water and two equivalents of dihydrogen. The investigations indicate that catalysts suitable for hydrogen autotransfer or borrowing hydrogen chemistry might also be suitable for acceptor-less dehydrogenative condensation reactions. PMID:25186522

  18. Chromatographic characterisation, under highly aqueous conditions, of a molecularly imprinted polymer binding the herbicide 2,4-dichlorophenoxyacetic acid.

    PubMed

    Legido-Quigley, C; Oxelbark, J; De Lorenzi, E; Zurutuza-Elorza, A; Cormack, P A G

    2007-05-15

    The affinity of a 2,4-dichlorophenoxyacetic acid (2,4-D) molecularly imprinted polymer (MIP), which was synthesised directly in an aqueous organic solvent, for its template (2,4-D) was studied and compared with the affinity exhibited by two other reference (control) polymers, NIPA and NIPB, for the same analyte. Zonal chromatography was performed to establish the optimal selectivity, expressed as imprinting factor (IF), under chromatographic conditions more aqueous than those described so far in the literature. Frontal analysis (FA) was performed on columns packed with these polymers, using an optimized mobile phase composed of methanol/phosphate buffer (50/50, v/v), to extract adsorption isotherm data and retrieve binding parameters from the best isotherm model. Surprisingly, the template had comparable and strong affinity for both MIP (K = 3.8x10(4) M(-1)) and NIPA (K = 1.9x10(4) M(-1)), although there was a marked difference in the saturation capacities of selective and non-selective sites, as one would expect for an imprinted polymer. NIPB acts as a true control polymer in the sense that it has relatively low affinity for the template (K = 8.0x10(2) M(-1)). This work provides the first frontal chromatographic characterization of such a polymer in a water-rich environment over a wide concentration range. The significance of this work stems from the fact that the chromatographic approach used is generic and can be applied readily to other analytes, but also because there is an increasing demand for well-characterised imprinted materials that function effectively in aqueous media and are thus well-suited for analytical science applications involving, for example, biofluids and environmental water samples.

  19. Oligo-Glycine Synthesis in an Aqueous Solution of Glycine Under Oxidative Conditions

    NASA Astrophysics Data System (ADS)

    Yamagata, Yukio; Yamashita, Atsunori; Inomata, Katsuhiko

    1980-03-01

    Di-and tri-glycine were synthesized in 1M aqueous solution of glycine by bubbling for 90 hr with oxygen discharged in the path from an oxygen cylinder. The peptides were also produced by an incubation at 37°C of 2M glycine solution prepared with 75% hydrogen peroxide, and the yields were traced for 200 days. The final yields were about 0.25% and 0.01% for di-and tri-glycine, respectively. The solution at 166 days of incubation was applied to a Sephadex G 10 column, and the fractions around the top of the chromatogram were found to increase the intensity of ninhydrin color about 4˜5 times after hydrolysis, indicating an existence of oligo-glycine. The solutions of 1M glycine and 0.5M diglycine prepared with 30% hydrogen peroxide were incubated at 37°C for 38 days, and di-and tetra-glycine were detected in the yields of 0.12% and 0.33%, respectively.

  20. Growth of La{sub 2}CuO{sub 4} nanofibers under a mild condition by using single walled carbon nanotubes as templates

    SciTech Connect

    Gao Lizhen . E-mail: lizhen@mech.uwa.edu.au; Wang Xiaolin; Chua, H.T.; Kawi, Sibudjing

    2006-07-15

    La{sub 2}CuO{sub 4} nanofibers (ca. 30 nm in diameter and 3 {mu}m in length) have been grown in situ by using single walled carbon nanotubes (SWNTs; ca. 2 nm in inner diameter; made via cracking CH{sub 4} over the catalyst of Mg{sub 0.8}Mo{sub 0.05}Ni{sub 0.10}Co{sub 0.05}O {sub x} at 800 deg. C) as templates under mild hydrothermal conditions and a temperature around 60 deg. C. During synthesis, the surfactant poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) and H{sub 2}O{sub 2} were added to disperse SWNTs and oxidize the reactants, respectively. The structure of La{sub 2}CuO{sub 4} nanofibers was confirmed by powder X-ray diffraction (XRD) and their morphologies were observed with field emission scanning electron microscope (FESEM) at the hydrothermal synthesis lasting for 5, 20 and 40 h, respectively. The La{sub 2}CuO{sub 4} crystals grew from needle-like (5 h) through stick-like (20 h) and finally to plate-like (40 h) fibers. Twenty hours is an optimum reaction time to obtain regular crystal fibers. The La{sub 2}CuO{sub 4} nanofibers are probably cubic rather than round and may capsulate SWNTs. - Graphical abstract: La{sub 2}CuO{sub 4} nanofibers have been grown in situ by using single walled carbon nanotubes as templates under mild hydrothermal conditions and a temperature around 60 deg. C. The La{sub 2}CuO{sub 4} crystals grew from needle-like (5 h) through stick-like (20 h) and finally to plate-like (40 h) fibers. The La{sub 2}CuO{sub 4} nanofibers are probably cubic rather than round and may capsulate SWNTs.

  1. Polyurethane foam loaded with sodium dodecylsulfate for the extraction of 'quat' pesticides from aqueous medium: Optimization of loading conditions.

    PubMed

    Vinhal, Jonas O; Lima, Claudio F; Cassella, Ricardo J

    2016-09-01

    The cationic herbicides paraquat, diquat and difenzoquat are largely used in different cultures worldwide. With this, there is an intrinsic risk of environmental contamination when these herbicides achieve natural waters. The goal of this work was to propose a novel and low-cost sorbent for the removal of the cited herbicides from aqueous medium. The proposed sorbent was prepared by loading polyurethane foam with sodium dodecylsulfate. The influence of several parameters (SDS concentration, HCl concentration and shaking time) on the loading process was investigated. The results obtained in this work demonstrated that all studied variables influenced the loading process, having significant effect on the extraction efficiency of the resulted PUF-SDS. At optimized conditions, the PUF was loaded by shaking 200mg of crushed foam with 200mL of a solution containing 5.0×10(-3)molL(-1) SDS and 0.25molL(-1) HCl, for 30min. The obtained PUF-SDS was efficient for removing the three herbicides from aqueous medium, achieving extraction percentages higher than 90%. The sorption process followed a pseudo second-order kinetics, which presented excellent predictive capacity of the amount of herbicide retained with time. PMID:27213562

  2. Photochemical decomposition of dissolved hydroxylated polybrominated diphenyl ethers under various aqueous conditions.

    PubMed

    Bastos, Patricia Moreira; Eriksson, Johan; Bergman, Ake

    2009-10-01

    The area of fire protection has grown over the last decades with an increasing use of brominated flame retardants (BFRs). Some of the BFRs are phenolic compounds as applied, e.g. tetrabromobisphenol A and 2,4,6-tribromophenol. Others, like the polybrominated diphenyl ethers (PBDEs), can be metabolized to phenolic compounds, i.e. polybrominated phenoxyphenols (OH-PBDEs). OH-PBDEs, have to our knowledge never been commercially produced, but some are well known natural products, and found in high concentrations in biota. The present study is aimed to determine the susceptibility of OH-PBDEs to undergo photolysis when dissolved in water and to compare their reactivity with a couple of PBDE congeners. A previously developed method for studies of photolysis was applied and adapted to include OH-PBDEs in water at pH 7 and 11, water/methanol and water/hydrogen peroxide. The results indicate a change in reaction rates for the photolysis of OH-PBDE in different aqueous media and pH dependence. The results from the present study show that hydroxylated compounds rapidly undergo photolytic transformations in water. The OH-PBDEs are more rapidly transformed then PBDE congeners with similar numbers of bromine substituents. All the OH-PBDEs, independent of structure, are rapidly transformed, with approx. the same rate, when hydrogen peroxide is present, indicating another route of reaction. Polybrominated dibenzo-p-dioxins (PBDDs) are indicated as transformation products upon photolysis of OH-PBDEs with a favorable bromine substitution pattern.

  3. Catalysis of peptide formation by inorganic oxides: high efficiency of alumina under mild conditions on the Earth-like planets.

    PubMed

    Basiuk, V A; Sainz-Rojas, J

    2001-01-01

    Amino acid condensation catalyzed by inorganic oxides is a widely recognized way for prebiotic peptide formation. Silica and alumina are widely distributed in the Earth-like planets' crust as minerals of different complexity, and thus are attractive model catalysts for the studies of abiotic peptide synthesis. Experiments performed in other laboratories have shown that this process can be efficient at > 80 degrees C, which is not easy to find on the planetary surface in combination with sufficient concentrations of amino acids and necessary catalysts. In the present work we tested catalytic activity of three forms of alumina (which proved to be an efficient catalyst for this process) in the intermolecular condensation of L-alanine. We expanded the temperature interval down to 55 degrees C and used the simplest permanent heating procedure, without employing fluctuating drying/wetting conditions. The most important finding is that even under the lowest temperature considered (i.e. 55 degrees C), short peptide formation can be detected already after 10-30 days of heating. This fact implies that the abiotic peptide formation might occur in a wide variety of planetary environments, without need for high temperatures, given the presence of amino acid building blocks and alumina-containing minerals.

  4. Optimization of Aqueous Extraction Conditions for Recovery of Phenolic Content and Antioxidant Properties from Macadamia (Macadamia tetraphylla) Skin Waste

    PubMed Central

    Dailey, Adriana; Vuong, Quan V.

    2015-01-01

    The macadamia is native to Australia and is now grown commercially around the world. Macadamia skin, known as waste, has been generated abundantly, but this ample source has had limited uses as a byproduct. The aim of this study was to develop optimal aqueous extraction conditions for the recovery of phenolic compounds and antioxidant properties from macadamia skin using Response Surface Methodology (RSM). Water was selected for optimizing the extraction conditions because it is a cheap, safe, and environmentally friendly solvent. The results showed that the RSM models were reliable for the prediction and evaluation of the tested variables. Within the tested ranges, temperature (°C), time (min), and sample-to-solvent ratio (g/100 mL), and their interactions, did not significantly affect phenolic compound (TPC), flavonoid, proanthocyanidin, CUPRAC, and FRAP contents. However, the time and the sample-to-solvent ratio significantly affected DPPH antioxidant activity and the ratio significantly affected ABTS antioxidant capacity. The optimal extraction conditions for the recovery of phenolic compounds and antioxidant properties were predicted and validated at a temperature of 90 °C, a time of 20 min, and a sample-to-solvent ratio of 5 g/100 mL. At these conditions, an extract with TPC of 86 mg GAE/g, flavonoids of 30 mg RUE/g, and proanthocyanidins of 97 mg CAE/g could be prepared with potent antioxidant capacity. PMID:26783954

  5. Optimization of Aqueous Extraction Conditions for Recovery of Phenolic Content and Antioxidant Properties from Macadamia (Macadamia tetraphylla) Skin Waste.

    PubMed

    Dailey, Adriana; Vuong, Quan V

    2015-01-01

    The macadamia is native to Australia and is now grown commercially around the world. Macadamia skin, known as waste, has been generated abundantly, but this ample source has had limited uses as a byproduct. The aim of this study was to develop optimal aqueous extraction conditions for the recovery of phenolic compounds and antioxidant properties from macadamia skin using Response Surface Methodology (RSM). Water was selected for optimizing the extraction conditions because it is a cheap, safe, and environmentally friendly solvent. The results showed that the RSM models were reliable for the prediction and evaluation of the tested variables. Within the tested ranges, temperature (°C), time (min), and sample-to-solvent ratio (g/100 mL), and their interactions, did not significantly affect phenolic compound (TPC), flavonoid, proanthocyanidin, CUPRAC, and FRAP contents. However, the time and the sample-to-solvent ratio significantly affected DPPH antioxidant activity and the ratio significantly affected ABTS antioxidant capacity. The optimal extraction conditions for the recovery of phenolic compounds and antioxidant properties were predicted and validated at a temperature of 90 °C, a time of 20 min, and a sample-to-solvent ratio of 5 g/100 mL. At these conditions, an extract with TPC of 86 mg GAE/g, flavonoids of 30 mg RUE/g, and proanthocyanidins of 97 mg CAE/g could be prepared with potent antioxidant capacity. PMID:26783954

  6. Hydrothermal diamond anvil cell for XAFS studies of first-row transition elements in aqueous solutions up to supercritical conditions

    USGS Publications Warehouse

    Bassett, William A.; Anderson, Alan J.; Mayanovic, Robert A.; Chou, I.-Ming

    2000-01-01

    A hydrothermal diamond anvil cell (HDAC) has been modified by drilling holes with a laser to within 150 ??m of the anvil face to minimize the loss of X-rays due to absorption and scatter by diamond. This modification enables acquisition of K-edge X-ray absorption fine structure (XAFS) spectra from first-row transition metal ions in aqueous solutions at temperatures ranging from 25??C to 660??C and pressures up to 800 MPa. These pressure-temperature (P-T) conditions are more than sufficient for carrying out experimental measurements that can provide data valuable in the interpretation of fluid inclusions in minerals found in ore-forming hydrothermal systems as well as other important lithospheric processes involving water. (C) 2000 Elsevier Science B.V. All rights reserved.

  7. Mild traumatic brain injury in the rat alters neuronal number in the limbic system and increases conditioned fear and anxiety-like behaviors.

    PubMed

    Meyer, Danielle L; Davies, Daniel R; Barr, Jeffrey L; Manzerra, Pasquale; Forster, Gina L

    2012-06-01

    Recent reports suggest that experiencing a mild closed head trauma or mild traumatic brain injury (mTBI) is associated with a greater incidence of anxiety disorders. Dysfunction of limbic structures, such as the medial prefrontal cortex, amygdala and hippocampus, is associated with the symptoms of anxiety disorders. Therefore, the goal of the current studies was to characterize the consequences of closed mTBI on these limbic structures and associated fear and anxiety-related behaviors. A weight-drop procedure was employed to induce mTBI in male rats. Rats were transcardically perfused 4 or 9 days following exposure to mTBI or control procedures, and neuronal number, brain region area, and the number of apoptotic cells in each region were determined. In separate groups of rats, the effects of mTBI on anxiety-like behaviors, motor function, nociception, and acquisition, retention and extinction of contextual fear were also assessed. Findings suggest that mTBI was associated with significant neuronal cell loss in the CA1 region of the dorsal hippocampus and increased cell number in subregions of the amygdala, both of which appear to be related to alterations to apoptosis in these regions following mTBI. Furthermore, mTBI increased expression of anxiety-like behaviors and conditioned fear, with no effect on motor performance or nociception. Overall, a single impact to the skull to mimic mTBI in rats produces discrete alterations to neuronal numbers within the limbic system and specific emotional deficits, providing a potential neurobiological link between mTBI and anxiety disorders.

  8. Coordinating Chiral Ionic Liquids: Design, Synthesis, and Application in Asymmetric Transfer Hydrogenation under Aqueous Conditions

    PubMed Central

    Vasiloiu, Maria; Gaertner, Peter; Zirbs, Ronald; Bica, Katharina

    2015-01-01

    Hydrophilic coordinating chiral ionic liquids with an amino alcohol substructure were developed and efficiently applied to the asymmetric reduction of ketones. Their careful design and adaptability to the desired reaction conditions allow for these chiral ionic liquids to be used as the sole source of chirality in a ruthenium-catalyzed transfer hydrogenation reaction of aromatic ketones. When used in this reaction system, these chiral ionic liquids afforded excellent yields and high enantioselectivities. PMID:26279638

  9. Determination of the optimum conditions for boric acid extraction with carbon dioxide gas in aqueous media from colemanite containing arsenic

    SciTech Connect

    Ata, O.N.; Colak, S.; Copur, M.; Celik, C.

    2000-02-01

    The Taguchi method was used to determine optimum conditions for the boric acid extraction from colemanite ore containing As in aqueous media saturated by CO{sub 2} gas. After the parameters were determined to be efficient on the extraction efficiency, the experimental series with two steps were carried out. The chosen experimental parameters for the first series of experiments and their ranges were as follows: (1) reaction temperature, 25--70 C; (2) solid-to-liquid ratio (by weight), 0.091 to 0.333; (3) gas flow rate (in mL/min), 66.70--711; (4) mean particle size, {minus}100 to {minus}10 mesh; (5) stirring speed, 200--600 rpm; (6) reaction time, 10--90 min. The optimum conditions were found to be as follows: reaction temperature, 70 C; solid-to-liquid ratio, 0.091; gas flow rate, 711 (in mL/min); particle size, {minus}100 mesh; stirring speed, 500 rpm; reaction time, 90 min. Under these optimum conditions, the boric acid extraction efficiency from the colemanite containing As was approximately 54%. Chosen experimental parameters for the second series of experiments and their ranges were as follows: (1) reaction temperature, 60--80 C; (2) solid-to-liquid ratio (by weight), 0.1000 to 0.167; (3) gas pressure (in atm), 1.5; 2.7; (4) reaction time, 45--120 min. The optimum conditions were found to be as follows: reaction temperature, 70 C; solid-to-liquid ratio, 0.1; gas pressure, 2.7 atm; reaction time, 120 min. Under these optimum conditions the boric acid extraction efficiency from the colemanite ore was approximately 75%. Under these optimum conditions, the boric acid extraction efficiency from calcined colemanite ore was approximately 99.55%.

  10. CHEMICAL TRANSFORMATIONS USING NON-TRADITIONAL APPROACHES: MICROWAVE-ASSISTED GREENER SYNTHESES IN AQUEOUS MEDIA OR UNDER SOLVENT-FREE CONDITIONS

    EPA Science Inventory

    Microwave (MW) irradiation in conjunction with water as reaction media has proven to be a 'greener' chemical approach for expeditious N-alkylation reactions of amines and hydrazines wherein the reactions under mildly basic conditions afford tertiary amines and double N<...

  11. Immobilization of selenate by iron in aqueous solution under anoxic conditions and the influence of uranyl

    NASA Astrophysics Data System (ADS)

    Puranen, Anders; Jonsson, Mats; Dähn, Rainer; Cui, Daqing

    2009-08-01

    In proposed high level radioactive waste repositories a large part of the spent nuclear fuel (SNF) canisters are commonly composed of iron. Selenium is present in spent nuclear fuel as a long lived fission product. This study investigates the influence of iron on the uptake of dissolved selenium in the form of selenate and the effect of the presence of dissolved uranyl on the above interaction of selenate. The iron oxide, and selenium speciation on the surfaces was investigated by Raman spectroscopy. X-ray Absorption Spectroscopy was used to determine the oxidation state of the selenium and uranium on the surfaces. Under the simulated groundwater conditions (10 mM NaCl, 2 mM NaHCO 3, <0.1 ppm O 2) the immobilized selenate was found to be reduced to oxidation states close to zero or lower and uranyl was found to be largely reduced to U(IV). The near simultaneous reduction of uranyl was found to greatly enhance the rate of selenate reduction. These findings suggest that the presence of uranyl being reduced by an iron surface could substantially enhance the rate of reduction of selenate under anoxic conditions relevant for a repository.

  12. Interactions of silicate glasses with aqueous environments under conditions of prolonged contact and flow

    NASA Technical Reports Server (NTRS)

    Barkatt, Aaron; Saad, E. E.; Adiga, R. B.; Sousanpour, W.; Barkatt, AL.; Feng, X.; O'Keefe, J. A.; Alterescu, S.

    1988-01-01

    This paper discusses mechanisms involving saturation and reactions that lead to the formation of altered phases in silicate glasses considered for use in geologic repositories for nuclear waste. It is shown that the rate of dissolution of silicate glasses exposed to a broad range of contact times, leachant compositions, and surface-to-volume ratios is strongly affected by the presence of reactive species such as Al, Mg, and Fe. The reactive materials may originate in the leachant or, under conditions of high surface-to-volume ratio, in the glass itself. The effects of glass composition on the course of the corrosion process can be viewed in terms of the formation of a surface layer on the leached glass; the type, composition, and structure of this layer control the dissolution behavior of the glass.

  13. Physical properties of rocks and aqueous fluids at conditions simulating near- and supercritical reservoirs

    NASA Astrophysics Data System (ADS)

    Kummerow, Juliane; Raab, Siegfried

    2016-04-01

    The growing interest in exploiting supercritical geothermal reservoirs calls for a thorough identification and understanding of physico-chemical processes occuring in geological settings with a high heat flow. In reservoir engineering, electrical sounding methods are common geophysical exploration and monitoring tools. However, a realistic interpretation of field measurements is based on the knowledge of both, the physical properties of the rock and those of the interacting fluid at defined temperature and pressure conditions. Thus, laboratory studies at simulated in-situ conditions provide a link between the field data and the material properties in the depth. The physico-chemical properties of fluids change dramatically above the critical point, which is for pure water 374.21 °C and 221.2 bar. In supercritical fluids mass transfer and diffusion-controlled chemical reactions are enhanced and cause mineral alterations. Also, ion mobility and ion concentration are affected by the change of physical state. All this cause changes in the electrical resistivity of supercritical fluids and may have considerable effects on the porosity and hydraulic properties of the rocks they are in contact with. While there are some datasets available for physical and chemical properties of water and single component salt solutions above their critical points, there exist nearly no data for electrical properties of mixed brines, representing the composition of natural geothermal fluids. Also, the impact of fluid-rock interactions on the electrical properties of multicomponent fluids in a supercritical region is scarcely investigated. For a better understanding of fluid-driven processes in a near- and supercritical geological environment, in the framework of the EU-funded FP7 program IMAGE we have measured (1) the electrical resistivity of geothermal fluids and (2) physical properties of fluid saturated rock samples at simulated in-situ conditions. The permeability and electrical

  14. Different MK-801 administration schedules induce mild to severe learning impairments in an operant conditioning task: role of buspirone and risperidone in ameliorating these cognitive deficits.

    PubMed

    Rapanelli, Maximiliano; Frick, Luciana Romina; Bernardez-Vidal, Micaela; Zanutto, Bonifacio Silvano

    2013-11-15

    Blockade of N-methyl-d-aspartate receptor (NMDA) by the noncompetitive NMDA receptor (NMDAR) antagonist MK-801 produces behavioral abnormalities and alterations in prefrontal cortex (PFC) functioning. Due to the critical role of the PFC in operant conditioning task learning, we evaluated the effects of acute, repeated postnatal injections of MK-801 (0.1mg/kg) on learning performance. We injected Long-Evans rats i.p. with MK-801 (0.1mg/kg) using three different administration schedules: injection 40 min before beginning the task (during) (n=12); injection twice daily for six consecutive days prior to beginning the experimental procedures (prior) (n=12); or twice daily subcutaneous injections from postnatal day 7 to 11 (postnatal) (n=12). Next, we orally administered risperidone (serotonin receptor 2A and dopamine receptor 2 antagonist, 1mg/kg) or buspirone (serotonin receptor 1A partial agonist, 10mg/kg) to animals treated with the MK-801 schedule described above. The postnatal and prior administration schedules produced severe learning deficits, whereas injection of MK-801 just before training sessions had only mild effects on acquisition of an operant conditioning. Risperidone was able to reverse the detrimental effect of MK-801 in the animals that were treated with MK-801 during and prior training sessions. In contrast, buspirone was only effective at mitigating the cognitive deficits induced by MK-801 when administered during the training procedures. The data demonstrates that NMDA antagonism disrupts basic mechanisms of learning in a simple PFC-mediated operant conditioning task, and that buspirone and risperidone failed to attenuate the learning deficits when NMDA neurotransmission was blocked in the early stages of the postnatal period.

  15. Flow and morphological conditions associated with the directional solidification of aqueous ammonium chloride

    SciTech Connect

    Magirl, C.S.; Incropera, F.P.

    1993-01-01

    Using 27% aq. NH[sub 4]Cl solutions as transparent analog, shadowgraphy and dye injection were used to observe flow and morphology in unidirectional solidification (UDS) from below. Dendritic crystals that form at the cold surface reject lighter, solute-deficient fluid, and instability is shown by finger-type double-diffusive convection. As the mushy two-phase region grows, perturbations at the liquidus interface cause localized remelting and downward development of channels. Solsutal plumes emanate from the channels, and in time, double-diffusive convection layers also form in the melt. When the solution is chilled at the sides as well as at the bottom, conditions are influenced by detachment and settling of crystals from the sidewall and by plumes from slanted channels. When a slow, oscillatory rocking motion is imposed on UDS, the freckle-type segregates in the final cast is suppressed. Within the melt, plumes and double-diffusive convection are eliminated. Inertially induced convection mixes the melt and produces a dense slurry. Although channels are eliminated from the bottom mushy region, overall heat transfer and macrosegregation in the cavity are unaffected by the slow rocking. Numerical simulations qualitatively predict trends in the field variables and provide insights on interdendritic flows and macrosegregation (freckle-, A-type segregates), although its quantitative predictions are hampered by simplifying assumptions.

  16. Flow and morphological conditions associated with the directional solidification of aqueous ammonium chloride. Annual performance report

    SciTech Connect

    Magirl, C.S.; Incropera, F.P.

    1993-01-01

    Using 27% aq. NH{sub 4}Cl solutions as transparent analog, shadowgraphy and dye injection were used to observe flow and morphology in unidirectional solidification (UDS) from below. Dendritic crystals that form at the cold surface reject lighter, solute-deficient fluid, and instability is shown by finger-type double-diffusive convection. As the mushy two-phase region grows, perturbations at the liquidus interface cause localized remelting and downward development of channels. Solsutal plumes emanate from the channels, and in time, double-diffusive convection layers also form in the melt. When the solution is chilled at the sides as well as at the bottom, conditions are influenced by detachment and settling of crystals from the sidewall and by plumes from slanted channels. When a slow, oscillatory rocking motion is imposed on UDS, the freckle-type segregates in the final cast is suppressed. Within the melt, plumes and double-diffusive convection are eliminated. Inertially induced convection mixes the melt and produces a dense slurry. Although channels are eliminated from the bottom mushy region, overall heat transfer and macrosegregation in the cavity are unaffected by the slow rocking. Numerical simulations qualitatively predict trends in the field variables and provide insights on interdendritic flows and macrosegregation (freckle-, A-type segregates), although its quantitative predictions are hampered by simplifying assumptions.

  17. Radiofluorination of diaryliodonium tosylates under aqueous-organic and cryptand-free conditions.

    PubMed

    Chun, Joong-Hyun; Telu, Sanjay; Lu, Shuiyu; Pike, Victor W

    2013-08-21

    Positron emission tomography (PET) has growing importance as a molecular imaging technique in clinical research and drug development. Methods for producing PET radiotracers utilizing cyclotron-produced [(18)F]fluoride ion (t1/2 = 109.7 min) without the need for complete removal of irradiated target [(18)O]water and addition of cryptand are keenly sought for practical convenience and efficiency. Several structurally diverse diaryliodonium tosylates, XArI(+)Ar'Y TsO(-) (X = H or p-MeO), were investigated in a microfluidic apparatus for their reactivity towards radiofluorination with high specific activity (no-carrier-added) [(18)F]fluoride ion in mixtures of DMF and irradiated target [(18)O]water in the absence of cryptand. Salts bearing a para or ortho electron-withdrawing group Y (e.g., Y = p-CN) reacted rapidly (∼3 min) to give the expected major [(18)F]fluoroarene product, [(18)F]FArY, in useful moderate radiochemical yields even when the solvent had an [(18)O]water content up to 28%. Salts bearing electron-withdrawing groups in meta position (e.g., Y = m-NO2), or an electron-donating substituent (Y = p-OMe), gave low radiochemical yields under the same conditions.

  18. Syntheses and crystal structures of benzene-sulfonate and -carboxylate copper polymers and their application in the oxidation of cyclohexane in ionic liquid under mild conditions.

    PubMed

    Hazra, Susanta; Ribeiro, Ana P C; Guedes da Silva, M Fátima C; Nieto de Castro, Carlos A; Pombeiro, Armando J L

    2016-09-21

    The syntheses, crystal structures and catalytic activities of the polymers derived from 2-(2-pyridylmethyleneamino)benzenesulfonic acid (HL), viz. [CuL(H2tma)]n (1) and [{Cu2L2(H2pma)}·(8H2O)]n (2) [H3tma = benzene-1,3,5-tricarboxylic (trimesic) acid and H4pma = benzene-1,2,4,5-tetracarboxylic (pyromellitic) acid], are presented. Despite the comparable combinations and compositions of ligands (sulfonate and carboxylate) in these two polymers the bridging moiety in 1 is sulfonate while in 2 it is carboxylate. Complexes 1 and 2 act as catalysts in the peroxidative oxidation of cyclohexane under mild conditions using either the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6] or acetonitrile as the solvent. The ionic liquid medium leads to increases in the yields and in the turnover numbers, achieved in shorter reaction times in comparison with those when using the conventional acetonitrile solvent. A simple recycling of the catalysts in the ionic liquid medium is achieved without loss of activity and selectivity.

  19. Syntheses and crystal structures of benzene-sulfonate and -carboxylate copper polymers and their application in the oxidation of cyclohexane in ionic liquid under mild conditions.

    PubMed

    Hazra, Susanta; Ribeiro, Ana P C; Guedes da Silva, M Fátima C; Nieto de Castro, Carlos A; Pombeiro, Armando J L

    2016-09-21

    The syntheses, crystal structures and catalytic activities of the polymers derived from 2-(2-pyridylmethyleneamino)benzenesulfonic acid (HL), viz. [CuL(H2tma)]n (1) and [{Cu2L2(H2pma)}·(8H2O)]n (2) [H3tma = benzene-1,3,5-tricarboxylic (trimesic) acid and H4pma = benzene-1,2,4,5-tetracarboxylic (pyromellitic) acid], are presented. Despite the comparable combinations and compositions of ligands (sulfonate and carboxylate) in these two polymers the bridging moiety in 1 is sulfonate while in 2 it is carboxylate. Complexes 1 and 2 act as catalysts in the peroxidative oxidation of cyclohexane under mild conditions using either the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6] or acetonitrile as the solvent. The ionic liquid medium leads to increases in the yields and in the turnover numbers, achieved in shorter reaction times in comparison with those when using the conventional acetonitrile solvent. A simple recycling of the catalysts in the ionic liquid medium is achieved without loss of activity and selectivity. PMID:27529408

  20. A new method of reconstituting the P-T conditions of fluid circulation in an accretionary prism (Shimanto, Japan) from microthermometry of methane-bearing aqueous inclusions

    NASA Astrophysics Data System (ADS)

    Raimbourg, Hugues; Thiéry, Régis; Vacelet, Maxime; Ramboz, Claire; Cluzel, Nicolas; Le Trong, Emmanuel; Yamaguchi, Asuka; Kimura, Gaku

    2014-01-01

    In paleo-accretionary prisms and the shallow metamorphic domains of orogens, circulating fluids trapped in inclusions are commonly composed of a mixture of salt water and methane, producing two types of fluid inclusions: methane-bearing aqueous and methane-rich gaseous fluid inclusions. In such geological settings, where multiple stages of deformation, veining and fluid influx are prevalent, textural relationships between aqueous and gaseous inclusions are often ambiguous, preventing the microthermometric determination of fluid trapping pressure and temperature conditions. To assess the P-T conditions of deep circulating fluids from the Hyuga unit of the Shimanto paleo-accretionary prism on Kyushu, Japan, we have developed a new computational code, applicable to the H2O-CH4-NaCl system, which allows the characterization of CH4-bearing aqueous inclusions using only the temperatures of their phase transitions estimated by microthermometry: Tmi, the melting temperature of ice; Thyd, the melting temperature of gas hydrate and Th,aq, homogenization temperature. This thermodynamic modeling calculates the bulk density and composition of aqueous inclusions, as well as their P-T isochoric paths in a P-T diagram with an estimated precision of approximatively 10%. We use this computational tool to reconstruct the entrapment P-T conditions of aqueous inclusions in the Hyuga unit, and we show that these aqueous inclusions cannot be cogenetic with methane gaseous inclusions present in the same rocks. As a result, we propose that pulses of a high-pressure, methane-rich fluid transiently percolated through a rock wetted by a lower-pressure aqueous fluid. By coupling microthermometric results with petrological data, we infer that the exhumation of the Hyuga unit from the peak metamorphic conditions was nearly isothermal and ended up under a very hot geothermal gradient. In subduction or collision zones, modeling aqueous fluid inclusions in the ternary H2O-CH4-NaCl system and not

  1. Chronic Mild Cold Conditioning Modulates the Expression of Hypothalamic Neuropeptide and Intermediary Metabolic-Related Genes and Improves Growth Performances in Young Chicks

    PubMed Central

    Nguyen, Phuong; Greene, Elizabeth; Ishola, Peter; Huff, Geraldine; Donoghue, Annie; Bottje, Walter; Dridi, Sami

    2015-01-01

    Background Low environmental temperatures are among the most challenging stressors in poultry industries. Although landmark studies using acute severe cold exposure have been conducted, still the molecular mechanisms underlying cold-stress responses in birds are not completely defined. In the present study we determine the effect of chronic mild cold conditioning (CMCC) on growth performances and on the expression of key metabolic-related genes in three metabolically important tissues: brain (main site for feed intake control), liver (main site for lipogenesis) and muscle (main site for thermogenesis). Methods 80 one-day old male broiler chicks were divided into two weight-matched groups and maintained in two different temperature floor pen rooms (40 birds/room). The temperature of control room was 32°C, while the cold room temperature started at 26.7°C and gradually reduced every day (1°C/day) to reach 19.7°C at the seventh day of the experiment. At day 7, growth performances were recorded (from all birds) and blood samples and tissues were collected (n = 10). The rest of birds were maintained at the same standard environmental condition for two more weeks and growth performances were measured. Results Although feed intake remained unchanged, body weight gain was significantly increased in CMCC compared to the control chicks resulting in a significant low feed conversion ratio (FCR). Circulating cholesterol and creatine kinase levels were higher in CMCC chicks compared to the control group (P<0.05). CMCC significantly decreased the expression of both the hypothalamic orexigenic neuropeptide Y (NPY) and anorexigenic cocaine and amphetamine regulated transcript (CART) in chick brain which may explain the similar feed intake between the two groups. Compared to the control condition, CMCC increased the mRNA abundance of AMPKα1/α2 and decreased mTOR gene expression (P<0.05), the master energy and nutrient sensors, respectively. It also significantly decreased the

  2. Effect of electrostatic boundary conditions and system size on the interfacial properties of water and aqueous solutions

    NASA Astrophysics Data System (ADS)

    Spohr, E.

    1997-10-01

    The consequences of the choice of electrostatic boundary conditions on the interfacial properties of water and on the free energy of ion adsorption from aqueous solution have been investigated. The Ewald summation method for lattices, which are periodic in two dimensions, is considered to be the most adequate method in slabs of finite thickness in one dimension. In agreement with the physics of the problem a field-free region in the bulk phases is observed. The use of spherical truncation methods like the shifted-force method leads to unphysical results. The electrostatic potential depends on the size of the system. Ewald summation methods for three-dimensional lattices lead to results in qualitative agreement with the corresponding two-dimensional lattice sum. The computed value of the electrostatic potential depends on an additional parameter, namely the lattice constant c in the direction perpendicular to the interface. The results for Ewald summation in three dimensions converge to the results for Ewald summation in two dimensions for large c, the shifted-force results converge to the same limit, when the surface area of the simulation cell becomes very large and the cut-off distance increases accordingly.

  3. Rare-earth metal oxide doped transparent mesoporous silica plates under non-aqueous condition as a potential UV sensor.

    PubMed

    Lee, Sang-Joon; Park, Sung Soo; Lee, Sang Hyun; Hong, Sang-Hyun; Ha, Chang-Sik

    2013-11-01

    Transparent mesoporous silica plates doped with rare-earth metal oxide were prepared using solvent-evaporation method based on the self-organization between structure-directing agent and silicate in a non-aqueous solvent. A triblock copolymer, Pluronic (F127 or P123), was used as the structure-directing agent, while tetraethyl orthosilicate (TEOS) was used as a silica source. The pore diameter and the surface area of the mesoporous silica plate prepared with the optimized conditions were ca 40 A and 600 m2 g(-1), respectively, for both structure-directing agent. Rare-earth metal oxides (Eu, Tb, Tm oxide) in mesochannel were formed via one-step synthetic route based on the preparation method of a silica plate. Optical properties of rare-earth metal oxide-doped mesoporous silica plates were investigated by UV irradiation and photoluminescence (PL) spectroscopy. Under the exitation wavelength of 254 nm, the doped mesoporous silica plates emitted red, green and blue for Eu, Tb and Tm oxides, respectively. Rare-earth metal oxide-doped mesoporous silica plates showed enhanced PL intensity compared to that of the bulk rare-earth metal oxide.

  4. XAFS measurements on zinc chloride aqueous solutions from ambient to supercritical conditions using the diamond anvil cell

    USGS Publications Warehouse

    Mayanovic, Robert A.; Anderson, Alan J.; Bassett, William A.; Chou, I.-Ming

    1999-01-01

    The structure and bonding properties of metal complexes in subcritical and supercritical fluids are still largely unknown. Conventional high pressure and temperature cell designs impose considerable limitations on the pressure, temperature, and concentration of metal salts required for measurements on solutions under supercritical conditions. In this study, we demonstrate the first application of the diamond anvil cell, specially designed for x-ray absorption studies of first-row transition metal ions in supercritical fluids. Zn K-edge XAFS spectra were measured from aqueous solutions of 1-2m ZnCl2 and up to 6m NaCl, at temperatures ranging from 25-660 ??C and pressures up to 800 MPa. Our results indicate that the ZnCl42- complex is predominant in the 1m ZnCl2/6m NaCl solution, while ZnCl2(H2O)2 is similarly predominant in the 2m ZnCl2 solution, at all temperatures and pressures. The Zn-Cl bond length of both types of chlorozinc(II) complexes was found to decrease at a rate of about 0.01 A??/100 ??C.

  5. Unprecedented Selective Oxidation of Styrene Derivatives using a Supported Iron Oxide Nanocatalyst in Aqueous Medium

    EPA Science Inventory

    Iron oxide nanoparticles supported on mesoporous silica-type materials have been successfully utilized in the aqueous selective oxidation of alkenes under mild conditions using hydrogen peroxide as a green oxidant. Catalysts could be easily recovered after completion of the reac...

  6. Effect of core body temperature, time of day, and climate conditions on behavioral patterns of lactating dairy cows experiencing mild to moderate heat stress.

    PubMed

    Allen, J D; Hall, L W; Collier, R J; Smith, J F

    2015-01-01

    Cattle show several responses to heat load, including spending more time standing. Little is known about what benefit this may provide for the animals. Data from 3 separate cooling management trials were analyzed to investigate the relationship between behavioral patterns in lactating dairy cows experiencing mild to moderate heat stress and their body temperature. Cows (n=157) were each fitted with a leg data logger that measured position and an intravaginal data logger that measures core body temperature (CBT). Ambient conditions were also collected. All data were standardized to 5-min intervals, and information was divided into several categories: when standing and lying bouts were initiated and the continuance of each bout (7,963 lying and 6,276 standing bouts). In one location, cows were continuously subjected to heat-stress levels according to temperature-humidity index (THI) range (THI≥72). The THI range for the other 2 locations was below and above a heat-stress threshold of 72 THI. Overall and regardless of period of day, cows stood up at greater CBT compared with continuing to stand or switching to a lying position. In contrast, cows lay down at lower CBT compared with continuing to lie or switching to a standing position, and lying bouts lasted longer when cows had lower CBT. Standing bouts also lasted longer when cattle had greater CBT, and they were less likely to lie down (less than 50% of lying bouts initiated) when their body temperature was over 38.8°C. Also, cow standing behavior was affected once THI reached 68. Increasing CBT decreased lying duration and increased standing duration. A CBT of 38.93°C marked a 50% likelihood a cow would be standing. This is the first physiological evidence that standing may help cool cows and provides insight into a communally observed behavioral response to heat.

  7. Highly Active Gold(I)-Silver(I) Oxo Cluster Activating sp³ C-H Bonds of Methyl Ketones under Mild Conditions.

    PubMed

    Pei, Xiao-Li; Yang, Yang; Lei, Zhen; Chang, Shan-Shan; Guan, Zong-Jie; Wan, Xian-Kai; Wen, Ting-Bin; Wang, Quan-Ming

    2015-04-29

    The activation of C(sp(3))-H bonds is challenging, due to their high bond dissociation energy, low proton acidity, and highly nonpolar character. Herein we report a unique gold(I)-silver(I) oxo cluster protected by hemilabile phosphine ligands [OAu3Ag3(PPhpy2)3](BF4)4 (1), which can activate C(sp(3))-H bonds under mild conditions for a broad scope of methyl ketones (RCOCH3, R = methyl, phenyl, 2-methylphenyl, 2-aminophenyl, 2-hydroxylphenyl, 2-pyridyl, 2-thiazolyl, tert-butyl, ethyl, isopropyl). Activation happens via triple deprotonation of the methyl group, leading to formation of heterometallic Au(I)-Ag(I) clusters with formula RCOCAu4Ag4(PPhpy2)4(BF4)5 (PPhpy2 = bis(2-pyridyl)phenylphosphine). Cluster 1 can be generated in situ via the reaction of [OAu3Ag(PPhpy2)3](BF4)2 with 2 equiv of AgBF4. The oxo ion and the metal centers are found to be essential in the cleavage of sp(3) C-H bonds of methyl ketones. Interestingly, cluster 1 selectively activates the C-H bonds in -CH3 rather than the N-H bonds in -NH2 or the O-H bond in -OH which is traditionally thought to be more reactive than C-H bonds. Control experiments with butanone, 3-methylbutanone, and cyclopentanone as substrates show that the auration of the C-H bond of the terminal methyl group is preferred over secondary or tertiary sp(3) C-H bonds; in other words, the C-H bond activation is influenced by steric effect. This work highlights the powerful reactivity of metal clusters toward C-H activation and sheds new light on gold(I)-mediated catalysis.

  8. Understanding and Exploitation of Neighboring Heteroatom Effect for the Mild N-Arylation of Heterocycles with Diaryliodonium Salts under Aqueous Conditions: A Theoretical and Experimental Mechanistic Study.

    PubMed

    Bihari, Tamás; Babinszki, Bence; Gonda, Zsombor; Kovács, Szabolcs; Novák, Zoltán; Stirling, András

    2016-07-01

    The mechanism of arylation of N-heterocycles with unsymmetric diaryliodonium salts is elucidated. The fast and efficient N-arylation reaction is interpreted in terms of the bifunctionality of the substrate: The consecutive actions of properly oriented Lewis base and Brønsted acid centers in sufficient proximity result in the fast and efficient N-arylation. The mechanistic picture points to a promising synthetic strategy where suitably positioned nucleophilic and acidic centers enable functionalization, and it is tested experimentally.

  9. Conductive polymer coatings for anodes in aqueous electrowinning

    NASA Astrophysics Data System (ADS)

    Alfantazi, A. M.; Moskalyk, R. R.

    2003-07-01

    This article discusses the potential application of electrically conductive polymers as protective coatings for permanent lead anodes employed in aqueous electrowinning processes. Also presented are results from a preliminary study of the performance of two intrinsically conductive polymers (polyaniline and poly 3,4,5-trifluorophenylthiophene [TFPT]) under mild copper electrowinning conditions as conductive and protective coatings on anodic surfaces. The laboratory results indicated that using lead alloy anodes coated with TFPT merits continued research.

  10. Ion-pair formation in aqueous strontium chloride and strontium hydroxide solutions under hydrothermal conditions by AC conductivity measurements.

    PubMed

    Arcis, H; Zimmerman, G H; Tremaine, P R

    2014-09-01

    Frequency-dependent electrical conductivities of solutions of aqueous strontium hydroxide and strontium chloride have been measured from T = 295 K to T = 625 K at p = 20 MPa, over a very wide range of ionic strength (3 × 10(-5) to 0.2 mol kg(-1)), using a high-precision flow AC conductivity instrument. Experimental values for the concentration-dependent equivalent conductivity, Λ, of the two electrolytes were fitted with the Turq-Blum-Bernard-Kunz ("TBBK") ionic conductivity model, to determine ionic association constants, K(A,m). The TBBK fits yielded statistically significant formation constants for the species SrOH(+) and SrCl(+) at all temperatures, and for Sr(OH)2(0) and SrCl2(0) at temperatures above 446 K. The first and second stepwise association constants for the ion pairs followed the order K(A1)(SrOH(+)) > K(A1)(SrCl(+)) > K(A2)[Sr(OH)2(0)] > K(A2)[SrCl2(0)], consistent with long-range solvent polarization effects associated with the lower static dielectric constant and high compressibility of water at elevated temperatures. The stepwise association constants to form SrCl(+) agree with previously reported values for CaCl(+) to within the combined experimental error at high temperatures and, at temperatures below ∼375 K, the values of log10 KA1 for strontium are lower than those for calcium by up to ∼0.3-0.4 units. The association constants for the species SrOH(+) and Sr(OH)2(0) are the first accurate values to be reported for hydroxide ion pairs with any divalent cation under these conditions.

  11. Serpentinization, iron oxidation, and aqueous conditions in an ophiolite: Implications for hydrogen production and habitability on Mars

    NASA Astrophysics Data System (ADS)

    Greenberger, Rebecca N.; Mustard, John F.; Cloutis, Edward A.; Pratt, Lisa M.; Sauer, Peter E.; Mann, Paul; Turner, Kathryn; Dyar, M. Darby; Bish, David L.

    2015-04-01

    weathering, and isotopic trends are consistent with kinetic fractionation. The extensive presence of tetrahedral Fe3+ in serpentine shows the system liberally produced H2 while the isotope systematics have implications for preservation of indicators of the aqueous conditions that formed serpentinites on Mars and their habitability.

  12. Mild traumatic brain injury.

    PubMed

    Katz, Douglas I; Cohen, Sara I; Alexander, Michael P

    2015-01-01

    Mild traumatic brain injury (TBI) is common but accurate diagnosis and defining criteria for mild TBI and its clinical consequences have been problematic. Mild TBI causes transient neurophysiologic brain dysfunction, sometimes with structural axonal and neuronal damage. Biomarkers, such as newer imaging technologies and protein markers, are promising indicators of brain injury but are not ready for clinical use. Diagnosis relies on clinical criteria regarding depth and duration of impaired consciousness and amnesia. These criteria are particularly difficult to confirm at the least severe end of the mild TBI continuum, especially when relying on subjective, retrospective accounts. The postconcussive syndrome is a controversial concept because of varying criteria, inconsistent symptom clusters and the evidence that similar symptom profiles occur with other disorders, and even in a proportion of healthy individuals. The clinical consequences of mild TBI can be conceptualized as two multidimensional disorders: (1) a constellation of acute symptoms that might be termed early phase post-traumatic disorder (e.g., headache, dizziness, imbalance, fatigue, sleep disruption, impaired cognition), that typically resolve in days to weeks and are largely related to brain trauma and concomitant injuries; (2) a later set of symptoms, a late phase post-traumatic disorder, evolving out of the early phase in a minority of patients, with a more prolonged (months to years), sometimes worsening set of somatic, emotional, and cognitive symptoms. The later phase disorder is highly influenced by a variety of psychosocial factors and has little specificity for brain injury, although a history of multiple concussions seems to increase the risk of more severe and longer duration symptoms. Effective early phase management may prevent or limit the later phase disorder and should include education about symptoms and expectations for recovery, as well as recommendations for activity modifications

  13. UV – INDUCED SYNTHESIS OF AMINO ACIDS FROM AQUEOUS STERILIZED SOLUTION OF AMMONIUM FORMATE AND AMMONIA UNDER HETROGENEOUS CONDITIONS

    PubMed Central

    Bisht, G.; Bisht, L. S.

    1990-01-01

    Irradiation of sterilized aqueous solution of ammonium formate and ammonia with UV light in the presence and or absence of certain inorganic sensitizers for 25 hrs. gave six ninhydrin positive products in appreciable amounts. Out of the six products observed fiver were characterized as lysine, serine, glutemic acid, n-amino butyric acid and leucine. The sensitizing effect of additives on ammonium formate was observed in the order; uranium oxide > ammonium formate > ferric oxide > arsenic oxide. PMID:22556511

  14. Universal reaction mechanism of boronic acids with diols in aqueous solution: kinetics and the basic concept of a conditional formation constant.

    PubMed

    Furikado, Yuki; Nagahata, Tomomi; Okamoto, Takuya; Sugaya, Tomoaki; Iwatsuki, Satoshi; Inamo, Masahiko; Takagi, Hideo D; Odani, Akira; Ishihara, Koji

    2014-10-01

    To establish a detailed reaction mechanism for the condensation between a boronic acid, RB(OH)2, and a diol, H2L, in aqueous solution, the acid dissociation constants (Ka(BL)) of boronic acid diol esters (HBLs) were determined based on the well-established concept of conditional formation constants of metal complexes. The pKa values of HBLs were 2.30, 2.77, and 2.00 for the reaction systems, 2,4-difluorophenylboronic acid and chromotropic acid, 3-nitrophenylboronic acid and alizarin red S, and phenylboronic acid and alizarin red S, respectively. A general and precise reaction mechanism of RB(OH)2 with H2L in aqueous solution, which can serve as a universal reaction mechanism for RB(OH)2 and H2L, was proposed on the basis of (a) the relative kinetic reactivities of the RB(OH)2 and its conjugate base, that is, the boronate ion, toward H2L, and (b) the determined pKa values of HBLs. The use of the conditional formation constant, K', based on the main reaction: RB(OH)2 + H2L (K1)⇌ RB(L)(OH)(-) + H3O(+) instead of the binding constant has been proposed for the general reaction of uncomplexed boronic acid species (B') with uncomplexed diol species (L') to form boronic acid diol complex species (esters, BL') in aqueous solution at pH 5-11: B' + L' (K')⇌ BL'. The proposed reaction mechanism explains perfectly the formation of boronic acid diol ester in aqueous solution.

  15. Relaxation of the structure of simple metal ion complexes in aqueous solutions at up to supercritical conditions

    USGS Publications Warehouse

    Mayanovic, Robert A.; Jayanetti, Sumedha; Anderson, Alan J.; Bassett, William A.; Chou, I.-Ming

    2003-01-01

    Recently x-ray absorption fine structure (XAFS) studies of various ions in aqueous solutions showed a variation of cation-ligand bond lengths, often coupled with other structure changes, with increasing temperatures. Thus, the variations of the structure of several metal ion complexes with temperature based on observations from the X-ray absorption fine structure (XAFS) studies in the hope that it will stimulate the development of either first- principles theory or molecular dynamics simulations that might adequately describes these results are discussed.

  16. Effective selenium volatilization under aerobic conditions and recovery from the aqueous phase by Pseudomonas stutzeri NT-I.

    PubMed

    Kagami, Tsubasa; Narita, Takanobu; Kuroda, Masashi; Notaguchi, Emi; Yamashita, Mitsuo; Sei, Kazunari; Soda, Satoshi; Ike, Michihiko

    2013-03-01

    Selenium is an important rare metal and its recovery from waste and wastewater is necessary for its sustainable utilization. Microbial selenium volatilization is suitable for selenium recovery from industrial wastewater because volatile selenium can be recovered in recyclable forms free from other chemicals. We found that Pseudomonas stutzeri NT-I can aerobically transform selenate, selenite, and biogenic elemental selenium into dimethyldiselenide as well as dimethylselenide; these were temporarily accumulated in the aqueous phase and then transferred into the gaseous phase. The rate of selenium volatilization using strain NT-I ranged 6.5-7.6 μmol/L/h in flask experiments and was much higher than the rates reported previously for other microbes. The selenium volatilization rate accelerated to 14 μmol/L/h in a jar fermenter. Furthermore, 82% of the selenium volatilized using strain NT-I was recovered with few impurities within 48 h in a simple gas trap with nitric acid, demonstrating that strain NT-I is a promising biocatalyst for selenium recovery through biovolatilization from the aqueous phase.

  17. The facile construction of the phthalazin-1(2H)-one scaffold via copper-mediated C–H(sp2)/C–H(sp) coupling under mild conditions

    PubMed Central

    Zhu, Wei; Wang, Bao; Zhou, Shengbin

    2015-01-01

    Summary A novel strategy for the construction of the phthalazin-1(2H)-one scaffold has been developed by means of a copper-mediated cascade C–H/C–H coupling and intramolecular annulations and a subsequent facile hydrazinolysis. This C–H activation transformation proceeds smoothly with wide generality, good functional tolerance and high stereo- and regioselectivity under mild conditions. Through the removal of the directing group, the resulting moiety could easily be transformed into the phthalazin-1(2H)-one scaffold, which is known to be a privileged moiety and a bioactive nucleus in pharmaceuticals. PMID:26664581

  18. Oxalic acid mediated synthesis of WO{sub 3}.H{sub 2}O nanoplates and self-assembled nanoflowers under mild conditions

    SciTech Connect

    Li Linzhi; Zhao Jingzhe; Wang Yi; Li Yunling; Ma Dechong; Zhao Yan; Hou Shengnan; Hao Xinli

    2011-07-15

    Tungsten oxide hydrate (WO{sub 3}.H{sub 2}O) nanoplates and flower-like assemblies were successfully synthesized via a simple aqueous method. The effects of reaction parameters in solution on the preparation were studied. Nanoplates and nanoflowers can be selectively prepared by changing the amount of H{sub 2}C{sub 2}O{sub 4}. In-situ assembly of nanoplates to nanoflowers was also proposed for the formation of assembled nanostructures. In addition, the reaction time and temperature have important effects on the sizes of the as-obtained samples. Crystal structure, morphology, and composition of final nanostructures were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Optical properties of the synthesized samples and the growth mechanism were studied by UV-vis detection. Degradation experiments of Rhodamine B (RhB) were also performed on samples of nanoplates and nanoflowers under visible light illumination. Nanoflower sample exhibited preferable photocatalytic property to nanoplate sample. - Graphical abstract: The oxalic acid has a key role for the structure of WO{sub 3}.H{sub 2}O evolution from plates to flowers and the dehydration process of WO{sub 3}.2H{sub 2}O to WO{sub 3}.H{sub 2}O. Highlights: > Tungsten oxides hydrate was synthesized via a simple aqueous method. > The size of WO{sub 3}.H{sub 2}O was controlled by the reaction time and temperature. > The assembly of WO{sub 3}.H{sub 2}O nanoplates to nanoflowers was achieved with higher H{sub 2}C{sub 2}O{sub 4}/Na{sub 2}WO{sub 4} ratio. > Oxalic acid has a key role in the dehydration process of WO{sub 3}.2H{sub 2}O to WO{sub 3}.H{sub 2}O.

  19. Effect of acute asenapine treatment on Fos expression in the forebrain structures under normal conditions and mild stress preconditioning in the rat.

    PubMed

    Majercikova, Zuzana; Cernackova, Alena; Horvathova, Lubica; Osacka, Jana; Pecenak, Jan; Kiss, Alexander

    2014-09-01

    Asenapine (ASE) is a novel atypical antipsychotic drug approved for the treatment of schizophrenia and bipolar disorder. Stress is an inseparable part of the human life, which may interfere with the therapeutic effect of different drugs. The aim of the present study was: (1) to delineate the quantitative and qualitative profiles of the ASE effect on Fos expression in the striatum, septum, nucleus accumbens, and the prefrontal cortex and (2) to find out whether a chronic unpredictable variable mild stress (CMS) preconditioning may modify the effect of acute ASE treatment. Stress paradigms included restrain, social isolation, crowding, swimming, and cold. The animals were exposed to CMS for 21 days and on the 22nd day received an injection of vehicle (saline 300 μl/rat s.c.) or ASE (0.3mg/kg s.c.). They were sacrificed 90 min after the treatments. Fos protein was visualized by avidin biotin peroxidase (ABC). Four groups of animals were investigated: controls+vehicle, controls+ASE, CMS+vehicle, and CMS+ASE. The number of Fos labeled neurons was calculated per total investigated area, which was selective for each structure, and also recalculated per unified sector. ASE treatment induced significant and very similar increase of the Fos expression in both ASE control and ASE CMS animals in comparison with saline control and CMS ones. Moreover, ASE induced regional differences in the number of Fos-positive neurons. In both ASE groups most pronounced response in the number of Fos profiles occurred in the dorsolateral striatum, ventrolateral septum, shell of the nucleus accumbens, and the medial prefrontal cortex. Mild Fos response was seen in the dorsomedial and ventromedial striatum and core of the nucleus accumbens. No response was seen in the dorsolateral septum. The present paper demonstrates for the first time the character of the Fos distribution in the forebrain structures induced by acute ASE treatment as well as ASE response to 21 days CMS preconditioning. The

  20. Microbiologically mediated reduction in the pitting of mild steel overlaid with plywood

    SciTech Connect

    Soracco, R J; Berger, L R; Berger, J A; Mayack, L A; Pope, D H; Wilde, E W

    1984-01-01

    Laboratory experiments were conducted to determine the role of microorganisms in the pitting of mild steel flooring, which had been overlaid with plywood. The experimental setups consisted of 4.8 mm (3/16 in.) mild steel plates covered with 12.7 mm (1/2 in.) thick pieces of plywood which were exposed to several different aqueous media supplemented with various combinations of a soil suspension and selected inorganic and organic compounds. Half of the replicate metal-wood-water setups were sterilized and aseptically maintained during incubation after which they were checked for the presence of viable microorganisms and pitting of the mild steel. Results of the first set of experiments showed that pitting of the mild steel specimens in many of these setups occurred after a reasonably short incubation period (3 to 6 months). However, the method used to exclude microorganisms by sterilizing the components separately was unsuccessful. In a second set of experiments, setups were sterilized by exposure to gamma irradiation after they had been assembled. The sterilized setups remained sterile after incubation while those which were not originally sterile still contained viable microorganisms. Pitting of the mild steel specimens was more severe when they were exposed to sterile conditions than when viable microorganisms were present. These experiments showed that while microorganisms are known to enhance corrosion processes in some circumstances, their presence can reduce corrosion in others.

  1. On the formation and structure of rare-earth element complexes in aqueous solutions under hydrothermal conditions with new data on gadolinium aqua and chloro complexes

    USGS Publications Warehouse

    Mayanovic, Robert A.; Anderson, Alan J.; Bassett, William A.; Chou, I.-Ming

    2007-01-01

    (III) chloro complexes increases steadily with temperature from 0.4 ?? 0.2 to 1.7 ?? 0.3 in the 0.006m chloride solution and from 0.9 ?? 0.7 to 1.8 ?? 0.7 in the 0.1m GdCl3 aqueous solution in the 300-500????C range. Conversely, the number of H2O ligands of Gd(H2O)??-nCln+3-n complexes decreases steadily from 8.9 ?? 0.4 to 5.8 ?? 0.7 in the 0.006m GdCl3 aqueous solution and from 9.0 ?? 0.5 to 5.3 ?? 1.0 in the 0.1m GdCl3 aqueous solution at temperatures from 25 to 500????C. Analysis of our results shows that the chloride ions partially displace the inner-shell water molecules during Gd(III) complex formation under hydrothermal conditions. The Gd-OH2 bond of the partially-hydrated Gd(III) chloro complexes exhibits slightly smaller rates of length contraction (??? 0.005??A??/100????C) for both solutions. The structural aspects of chloride speciation of Gd(III) as measured from this study and of Yb(III) as measured from our previous experiments are consistent with the solubility of these and other REE in deep-sea hydrothermal fluids. ?? 2006 Elsevier B.V. All rights reserved.

  2. The Effects of Mild Hearing Loss on Infant Auditory Function.

    ERIC Educational Resources Information Center

    Nozza, Robert J.

    1994-01-01

    A review of laboratory research estimating effects of mild hearing impairment on infant speech perception abilities, under conditions simulating mild hearing loss in normal hearing infants, suggests that even mild alterations of auditory input during infancy may have significant developmental consequences. Results support identification,…

  3. Metabolism and dissipation kinetics of a novel protoporphyrinogen IX oxidase herbicide [oxadiargyl] in various buffered aqueous system under laboratory-simulated condition.

    PubMed

    Sanyal, Nilanjan; Alam, Samsul; Pradhan, Saswati; Banerjee, Kaushik; Chowdhury, Ashim; Aktar, Md Wasim

    2015-07-01

    Present investigation was carried out using two commercial products Raft (oxadiargyl 6% EC) and Topstar (oxadiargyl 80% WP) of Oxadiargyl {5-tert-butyl-3[2,4-dichloro-5-(prop-2-ynyloxy)phenyl]-1,3,4-oxadiazol-2 (3H)-one} to investigate the persistence behavior and metabolism of the herbicide in various aqueous system under different pH condition. Half-life values revealed that alkaline hydrolysis played a dominant role in hydrolytic degradation of this compound. Q-ToF micromass study with the alkaline fractions of oxadiargyl indicated the formation of five metabolites, which was further characterized from their mass fragmentation data. The nature of metabolites formed indicated that heterocyclic oxadiazoline ring cleavage was found to be the main pathway of hydrolytic transformation of oxadiargyl.

  4. Effect of enzymatic deamidation of soy protein by protein-glutaminase on the flavor-binding properties of the protein under aqueous conditions.

    PubMed

    Suppavorasatit, Inthawoot; Cadwallader, Keith R

    2012-08-15

    The effect of the enzymatic deamidation by protein-glutaminase (PG) on flavor-binding properties of soy protein isolate (SPI) under aqueous conditions was evaluated by a modified equilibrium dialysis (ultrafiltration) technique. Binding parameters, such as number of binding sites (n) and binding constants (K), were derived from Klotz plots. The partial deamidation of SPI by PG (43.7% degree of deamidation) decreased overall flavor-binding affinity (nK) at 25 °C for both vanillin and maltol by approximately 9- and 4-fold, respectively. The thermodynamic parameters of binding indicated that the flavor-protein interactions were spontaneous (negative ΔG°) and that the driving force of the interactions shifted from entropy to enthalpy driven as a result of deamidation. Deamidation of soy protein caused a change in the mechanism of binding from hydrophobic interactions or covalent bonding (Schiff base formation) to weaker van der Waals forces or hydrogen bonding. PMID:22831747

  5. Mass spectrometric elucidation of triacylglycerol content of Brevoortia tyrannus (menhaden) oil using non-aqueous reversed-phase liquid chromatography under ultra high pressure conditions.

    PubMed

    Dugo, Paola; Beccaria, Marco; Fawzy, Nermeen; Donato, Paola; Cacciola, Francesco; Mondello, Luigi

    2012-10-12

    A non-aqueous reversed phase high performance liquid chromatography method was developed, and optimized for triacylglycerol analysis in a Brevoortia tyrannus (menhaden) oil sample. Four columns were serially coupled to tackle such a task, for a total length of 60 cm of shell-packed stationary phase, and operated under ultra high pressure conditions. As detection, positive-ion atmospheric pressure chemical ionization mass spectrometry was used to attain identification of the analyzed sample components. A number of 137 triacylglycerols containing up to 19 fatty acids, with 14-22 carbon atom alkyl chain length and 0-6 double bonds, were positively identified in the complex lipidic sample. This is the first work that reports an extensive characterization of the triacylglycerol fraction of menhaden oil. PMID:22503927

  6. Surface oxidation of pyrite under ambient atmospheric and aqueous (pH = 2 to 10) conditions: electronic structure and mineralogy from X-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Todd, E. C.; Sherman, D. M.; Purton, J. A.

    2003-03-01

    The nature of the surface oxidation phase on pyrite, FeS 2, reacted in aqueous electrolytes at pH = 2 to 10 and with air under ambient atmospheric conditions was studied using synchrotron-based oxygen K edge, sulfur L III edge, and iron L II,III edge X-ray absorption spectroscopy. We demonstrate that O K edge X-ray absorption spectra provide a sensitive probe of sulfide surface oxidation that is complementary to X-ray photoelectron spectroscopy. Using total electron yield detection, the top 20 to 50 Å of the pyrite surface is characterized. In air, pyrite oxidizes to form predominantly ferric sulfate. In aqueous air-saturated solutions, the surface oxidation products of pyrite vary with pH, with a marked transition occurring around pH 4. Below pH = 4, a ferric (hydroxy)sulfate is the main oxidation product on the pyrite surface. At higher pH, we find iron(III) oxyhydroxide in addition to ferric (hydroxy)sulfate on the surface. Under the most alkaline conditions, the O K edge spectrum closely resembles that of goethite, FeOOH, and the surface is oxidized to the extent that no FeS 2 can be detected in the X-ray absorption spectra. In a 1.667 × 10 -3 mol/L Fe 3+ solution with ferric iron present as FeCl 3 in NaCl, the oxidation of pyrite is autocatalyzed, and formation of the surface iron(III) oxyhydroxide phase is promoted at low pH.

  7. Electrochemical efficacy of a carboxylated multiwalled carbon nanotube filter for the removal of ibuprofen from aqueous solutions under acidic conditions.

    PubMed

    Bakr, Ahmed Refaat; Rahaman, Md Saifur

    2016-06-01

    This study provides insight into the efficiency of a functionalized multiwalled carbon nanotube filter for the removal of an anti-inflammatory drug, ibuprofen, through conventional filtration and electrochemical filtration processes. A comparison was made between carboxylated multiwalled carbon nanotubes (MWNTs-COOH) and pristine multiwalled carbon nanotubes (MWNTs) in order to emphasize the enhanced performance of MWNTs-COOH for the removal of ibuprofen using an electrochemical filtration process under acidic conditions. Ibuprofen-removal trials were evaluated based on absorbance values obtained using a UV/Vis spectrophotometer, and possible degradation products were identified using liquid chromatography mass spectrometry (LC-MS). The results exhibited near complete removal of ibuprofen by MWNTs-COOH at lower applied potentials (2 V), at lower flow rates, and under acidic conditions, which can be attributed to the generation of superoxides and their active participation in simultaneous degradation of ibuprofen, and its by-products, under these conditions. At higher applied potential (3 V), the possible participation of both bulk indirect oxidation reactions, and direct electron transfer were hypothesized for the removal behavior over time (breakthrough). At 3 V under acidic conditions, near 100% removal of the target molecule was achieved and was attributed to the enhanced generation of electroactive species toward bulk chemical reactions and a possible contribution from direct electron transfer under these conditions. The degradation by-products of ibuprofen were effectively removed by allowing longer residence time during the filtration process. Moreover, the effect of temperature was studied, yet showed a non-significant effect on the overall removal process.

  8. Fabrication of Thin Films of α-Fe2O3 via Atomic Layer Deposition Using Iron Bisamidinate and Water under Mild Growth Conditions.

    PubMed

    Avila, Jason R; Kim, Dong Wook; Rimoldi, Martino; Farha, Omar K; Hupp, Joseph T

    2015-08-01

    Atomic layer deposition (ALD) has been shown to be an excellent method for depositing thin films of iron oxide. With limited iron precursors available, the methods widely used require harsh conditions such as high temperatures and/or the use of oxidants such as ozone or peroxide. This letter aims to show that bis(N,N'-di-t-butylacetamidinato) iron(II) (iron bisamidinate or FeAMD) is an ideal ALD precursor because of its reactivity with water and relative volatility. Using in situ QCM analysis, we show outstanding conformal self-limiting growth of FeOx using FeAMD and water at temperatures lower than 200 °C. By annealing thin films of FeOx at 500 °C, we observe the formation of α-Fe2O3, confirming that we can use FeAMD to fabricate thin films of catalytically promising iron oxide materials using moderate growth conditions. PMID:26192606

  9. Fabrication of Thin Films of α-Fe2O3 via Atomic Layer Deposition Using Iron Bisamidinate and Water under Mild Growth Conditions.

    PubMed

    Avila, Jason R; Kim, Dong Wook; Rimoldi, Martino; Farha, Omar K; Hupp, Joseph T

    2015-08-01

    Atomic layer deposition (ALD) has been shown to be an excellent method for depositing thin films of iron oxide. With limited iron precursors available, the methods widely used require harsh conditions such as high temperatures and/or the use of oxidants such as ozone or peroxide. This letter aims to show that bis(N,N'-di-t-butylacetamidinato) iron(II) (iron bisamidinate or FeAMD) is an ideal ALD precursor because of its reactivity with water and relative volatility. Using in situ QCM analysis, we show outstanding conformal self-limiting growth of FeOx using FeAMD and water at temperatures lower than 200 °C. By annealing thin films of FeOx at 500 °C, we observe the formation of α-Fe2O3, confirming that we can use FeAMD to fabricate thin films of catalytically promising iron oxide materials using moderate growth conditions.

  10. Template Catalysis by Metal-Ligand Cooperation. C-C Bond Formation via Conjugate Addition of Non-activated Nitriles under Mild, Base-free Conditions Catalyzed by a Manganese Pincer Complex.

    PubMed

    Nerush, Alexander; Vogt, Matthias; Gellrich, Urs; Leitus, Gregory; Ben-David, Yehoshoa; Milstein, David

    2016-06-01

    The first example of a catalytic Michael addition reaction of non-activated aliphatic nitriles to α,β-unsaturated carbonyl compounds under mild, neutral conditions is reported. A new de-aromatized pyridine-based PNP pincer complex of the Earth-abundant, first-row transition metal manganese serves as the catalyst. The reaction tolerates a variety of nitriles and Michael acceptors with different steric features and acceptor strengths. Mechanistic investigations including temperature-dependent NMR spectroscopy and DFT calculations reveal that the cooperative activation of alkyl nitriles, which leads to the generation of metalated nitrile nucleophile species (α-cyano carbanion analogues), is a key step of the mechanism. The metal center is not directly involved in the catalytic bond formation but rather serves, cooperatively with the ligand, as a template for the substrate activation. This approach of "template catalysis" expands the scope of potential donors for conjugate addition reactions. PMID:27164437

  11. [Adsorption of calcium ion from aqueous solution using Na(+)-conditioned clinoptilolite for hot-water softening].

    PubMed

    Zhang, Shuo; Wang, Dong; Chen, Yuan-Chao; Zhang, Xing-Wen; Chen, Gui-Jun

    2015-02-01

    This work investigated adsorptive removal of calcium ion (Ca2+) by virtue of Na(+) -conditioned clinoptilolite simulating the process of softening for industrial hot-water system. Influential factors such as the activation/regeneration of sorbent and solution pH were tested. The kinetics/thermodynamics for adsorption of Ca2+ were analyzed and discussed. Results showed that: (1) The adsorption rate was in good agreement with the pseudo-second order kinetic models, and the process of adsorption better followed the Langmuir model; (2) Higher solution temperature allowed an enhanced efficiency on Ca2+ removal, albeit the maximum adsorption capacity of Na(+)-conditioned clinoptilolite was hardly affected; (3) The process of adsorption was dominated by chemisorption, and also characterized by entropy increase with spontaneous/endothermic nature; (4) Solution temperature was suggested to be controlled within the range of 6 to 10, and more than 9 times of sorbent regeneration could be ensured for an effective adsorption towards Ca2+ with initial concentration less than 20 mg x L(-1). It was demonstrated that the activated clinoptilolite should be a promising alternative adsorbent for industrial hot-water softening. PMID:26031107

  12. A study of X100 pipeline steel passivation in mildly alkaline bicarbonate solutions using electrochemical impedance spectroscopy under potentiodynamic conditions and Mott-Schottky

    NASA Astrophysics Data System (ADS)

    Gadala, Ibrahim M.; Alfantazi, Akram

    2015-12-01

    The key steps involved in X100 pipeline steel passivation in bicarbonate-based simulated soil solutions from the pre-passive to transpassive potential regions have been analyzed here using a step-wise anodizing-electrochemical impedance spectroscopy (EIS) routine. Pre-passive steps involve parallel dissolution-adsorption in early stages followed by clear diffusion-adsorption control shortly before iron hydroxide formation. Aggressive NS4 chlorides/sulfate promote steel dissolution whilst inhibiting diffusion in pre-passive steps. Diffusive and adsorptive effects remain during iron hydroxide formation, but withdraw shortly thereafter during its removal and the development of the stable iron carbonate passive layer. Passive layer protectiveness is evaluated using EIS fitting, current density analysis, and correlations with semiconductive parameters, consistently revealing improved robustness in colder, bicarbonate-rich, chloride/sulfate-free conditions. Ferrous oxide formation at higher potentials results in markedly lower impedances with disordered behavior, and the involvement of the iron(III) valence state is observed in Mott-Schottky tests exclusively for 75 °C conditions.

  13. Application of zero-valent iron nanoparticles for the removal of aqueous zinc ions under various experimental conditions.

    PubMed

    Liang, Wen; Dai, Chaomeng; Zhou, Xuefei; Zhang, Yalei

    2014-01-01

    Application of zero-valent iron nanoparticles (nZVI) for Zn²⁺ removal and its mechanism were discussed. It demonstrated that the uptake of Zn²⁺ by nZVI was efficient. With the solids concentration of 1 g/L nZVI, more than 85% of Zn²⁺ could be removed within 2 h. The pH value and dissolved oxygen (DO) were the important factors of Zn²⁺ removal by nZVI. The DO enhanced the removal efficiency of Zn²⁺. Under the oxygen-contained condition, oxygen corrosion gave the nZVI surface a shell of iron (oxy)hydroxide, which could show high adsorption affinity. The removal efficiency of Zn²⁺ increased with the increasing of the pH. Acidic condition reduced the removal efficiency of Zn²⁺ by nZVI because the existing H⁺ inhibited the formation of iron (oxy)hydroxide. Adsorption and co-precipitation were the most likely mechanism of Zn²⁺ removal by nZVI. The FeOOH-shell could enhance the adsorption efficiency of nZVI. The removal efficiency and selectivity of nZVI particles for Zn²⁺ were higher than Cd²⁺. Furthermore, a continuous flow reactor for engineering application of nZVI was designed and exhibited high removal efficiency for Zn²⁺. PMID:24416439

  14. Engineered protein A ligands, derived from a histidine-scanning library, facilitate the affinity purification of IgG under mild acidic conditions

    PubMed Central

    2014-01-01

    Background In antibody purification processes, the acidic buffer commonly used to elute the bound antibodies during conventional affinity chromatograph, can damage the antibody. Herein we describe the development of several types of affinity ligands which enable the purification of antibodies under much milder conditions. Results Staphylococcal protein A variants were engineered by using both structure-based design and combinatorial screening methods. The frequency of amino acid residue substitutions was statistically analyzed using the sequences isolated from a histidine-scanning library screening. The positions where the frequency of occurrence of a histidine residue was more than 70% were thought to be effective histidine-mutation sites. Consequently, we identified PAB variants with a D36H mutation whose binding of IgG was highly sensitive to pH change. Conclusion The affinity column elution chromatograms demonstrated that antibodies could be eluted at a higher pH (∆pH**≧2.0) than ever reported (∆pH = 1.4) when the Staphylococcal protein A variants developed in this study were used as affinity ligands. The interactions between Staphylococcal protein A and IgG-Fab were shown to be important for the behavior of IgG bound on a SpA affinity column, and alterations in the affinity of the ligands for IgG-Fab clearly affected the conditions for eluting the bound IgG. Thus, a histidine-scanning library combined with a structure-based design was shown to be effective in engineering novel pH-sensitive proteins. PMID:25057290

  15. Chemical Reactions of Portland Cement with Aqueous CO2 and Their Impacts on Cement's Mechanical Properties under Geologic CO2 Sequestration Conditions.

    PubMed

    Li, Qingyun; Lim, Yun Mook; Flores, Katharine M; Kranjc, Kelly; Jun, Young-Shin

    2015-05-19

    To provide information on wellbore cement integrity in the application of geologic CO2 sequestration (GCS), chemical and mechanical alterations were analyzed for cement paste samples reacted for 10 days under GCS conditions. The reactions were at 95 °C and had 100 bar of either N2 (control condition) or CO2 contacting the reaction brine solution with an ionic strength of 0.5 M adjusted by NaCl. Chemical analyses showed that the 3.0 cm × 1.1 cm × 0.3 cm samples were significantly attacked by aqueous CO2 and developed layer structures with a total attacked depth of 1220 μm. Microscale mechanical property analyses showed that the hardness and indentation modulus of the carbonated layer were 2-3 times greater than for the intact cement, but those in the portlandite-dissolved region decreased by ∼50%. The strength and elastic modulus of the bulk cement samples were reduced by 93% and 84%, respectively. The properties of the microscale regions, layer structure, microcracks, and swelling of the outer layers combined to affect the overall mechanical properties. These findings improve understanding of wellbore integrity from both chemical and mechanical viewpoints and can be utilized to improve the safety and efficiency of CO2 storage.

  16. Chemical Reactions of Portland Cement with Aqueous CO2 and Their Impacts on Cement's Mechanical Properties under Geologic CO2 Sequestration Conditions.

    PubMed

    Li, Qingyun; Lim, Yun Mook; Flores, Katharine M; Kranjc, Kelly; Jun, Young-Shin

    2015-05-19

    To provide information on wellbore cement integrity in the application of geologic CO2 sequestration (GCS), chemical and mechanical alterations were analyzed for cement paste samples reacted for 10 days under GCS conditions. The reactions were at 95 °C and had 100 bar of either N2 (control condition) or CO2 contacting the reaction brine solution with an ionic strength of 0.5 M adjusted by NaCl. Chemical analyses showed that the 3.0 cm × 1.1 cm × 0.3 cm samples were significantly attacked by aqueous CO2 and developed layer structures with a total attacked depth of 1220 μm. Microscale mechanical property analyses showed that the hardness and indentation modulus of the carbonated layer were 2-3 times greater than for the intact cement, but those in the portlandite-dissolved region decreased by ∼50%. The strength and elastic modulus of the bulk cement samples were reduced by 93% and 84%, respectively. The properties of the microscale regions, layer structure, microcracks, and swelling of the outer layers combined to affect the overall mechanical properties. These findings improve understanding of wellbore integrity from both chemical and mechanical viewpoints and can be utilized to improve the safety and efficiency of CO2 storage. PMID:25893278

  17. Experimental investigation and planetary implications of the stability of clathrate hydrates in aqueous solution at icy satellite conditions

    NASA Astrophysics Data System (ADS)

    Dunham, M.; Choukroun, M.; Barmatz, M.; Hodyss, R. P.; Smythe, W. D.

    2012-12-01

    Clathrate hydrates consist of hydrogen-bonded water molecules forming cages in which gas molecules are trapped individually. They are among the favored volatile reservoirs in solar system bodies, and are expected to play an important role in many processes: accretion of volatiles in planetesimals, outgassing on Titan, Enceladus, and comets. Their insulating thermal properties and high mechanical strength also bear important implications for understanding the evolution of icy satellites like Europa. However, the conditions allowing for their formation and/or their dissociation and the release of volatiles to the atmosphere (Titan) or the plumes (Enceladus) are still poorly understood. This is mainly because of a lack of knowledge on the stability of mixed clathrate hydrates in presence of anti-freeze agents such as ammonia. We have developed a high-pressure cryogenic calorimeter to address this deficiency in the literature. This liquid nitrogen - cooled Setaram BT2.15 calorimeter is located at the JPL Ice Physics Laboratory. The temperature range achievable with this instrument is 77-473 K. This calorimeter uses Calvet elements (3D arrays of thermocouples) to measure the heat flow required to follow a predefined heating rate within a sample and a reference cell with a resolution of 0.1 μW. A gas handling system has been designed and fabricated in house to reach pressures up to 100 bars, corresponding to several km depth in icy satellites. The thermodynamic properties of CO2 and CH4 clathrates with ammonia are under investigation, and the results will be used to constrain a statistical thermodynamic model of clathrates for applications to planetary environments. Preliminary results will be shown at the meeting. This work has been conducted at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. Support from the Minnesota Space Grant Consortium, the NASA Outer Planets Research program, and government sponsorship are gratefully

  18. Aqueous Conditions and Habitability Associated with Formation of a Serpentinite: Using Analyses of Ferric Iron and Stable Carbon Isotopes to Reconstruct Hydrogen Production

    NASA Astrophysics Data System (ADS)

    Greenberger, R. N.; Mustard, J. F.; Cloutis, E.; Pratt, L. M.; Sauer, P. E.; Mann, P.; Turner, K.; Dyar, M. D.

    2014-12-01

    Serpentine deposits on Mars have generated significant interest because byproducts of serpentinization, H2 and CH4, can be important energy sources for subsurface microbial communities. H2 is produced through Fe2+ oxidation to form magnetite and Fe3+-bearing serpentine. In serpentine, Fe3+ goes into octahedral sites first, then tetrahedral sites [Marcaillou et al., 2011, EPSL]. We use Fe oxidation state and coordination in an Early Ordovician serpentinite in Norbestos, Quebec, as proxies for H2 production and stable isotopes of carbonates to understand past aqueous conditions at the Canadian Space Agency's 2012 Mars Methane Analogue Mission site. Rock outcrops were imaged with a visible hyperspectral imager (420-720 nm), and samples were imaged in the laboratory with the same imager and a near infrared imager (650-1100 nm). Other analyses determined major element chemistry (ICP-AES and C analyses), mineralogy (XRD), Fe phases (Mössbauer spectroscopy), and stable isotopes of carbonates. Fe oxidation state and coordination (tetrahedral vs octahedral) were mapped in samples and outcrops using imaging data. We focused on locations with tetrahedral Fe3+ in serpentine as these are the most serpentinized sites with maximum H2 production. Carbonate samples from ~100-200 m south of a shear zone are enriched in 13C (δ13C up to +16.12‰ vs VPDB) resulting from production of CH4 depleted in 13C in a system closed to C addition but open to CH4 escape. This alteration occurred at elevated temperatures and low water/rock ratios. In the shear zone, lower δ13C values (most < +2‰) positively correlated with δ18O likely result from kinetic fractionation under recent low temperature conditions. Spectroscopy suggests that much of this deposit underwent advanced serpentinization to produce significant H2. Isotopic signatures of carbonates precipitated during serpentinization outside the shear zone illuminate the temperatures (elevated) and chemistries of fluids (high Ca2+, low CO

  19. Removal of mercury (II) from aqueous solution using papain immobilized on alginate bead: optimization of immobilization condition and modeling of removal study.

    PubMed

    Bhattacharyya, Aparupa; Dutta, Susmita; De, Parameswar; Ray, Parthasarathi; Basu, Srabanti

    2010-12-01

    Papain having the characteristics of metal binding ability is immobilized on alginate bead. Design Expert Software (Version 7.1.6) uses Response Surface Methodology (RSM) for statistical designing of operating condition for immobilization of papain on alginate bead considering concentration of papain, concentration of sodium alginate, concentration of calcium chloride and pH as numeric factors and Specific Enzymatic Activity (SEA) of immobilized papain sample as response. Immobilization using 25.96 g/L papain, 20 g/L sodium alginate and 20 g/L calcium chloride at pH 7 gives the desired product as indicated by ANOVA (Analysis of Variance). Three parameters viz., initial concentration of mercury (II), amount of AIP and pH are varied in a systematic manner. Maximum 98.88% removal of mercury (II) has been achieved within 8 min when simulated aqueous solution of mercury (II) with initial concentration of 10mg/L has been contacted with 5 g of AIP at pH 9 and at 35 degrees C in a batch contactor. A mathematical model has been developed and the value of equilibrium constant for binding of mercury (II) with AIP has been found to be 126797.3. PMID:20696575

  20. Defect formation in aqueous environment: Theoretical assessment of boron incorporation in nickel ferrite under conditions of an operating pressurized-water nuclear reactor (PWR)

    NASA Astrophysics Data System (ADS)

    Rák, Zs.; Bucholz, E. W.; Brenner, D. W.

    2015-06-01

    A serious concern in the safety and economy of a pressurized water nuclear reactor is related to the accumulation of boron inside the metal oxide (mostly NiFe2O4 spinel) deposits on the upper regions of the fuel rods. Boron, being a potent neutron absorber, can alter the neutron flux causing anomalous shifts and fluctuations in the power output of the reactor core. This phenomenon reduces the operational flexibility of the plant and may force the down-rating of the reactor. In this work an innovative approach is used to combine first-principles calculations with thermodynamic data to evaluate the possibility of B incorporation into the crystal structure of NiFe2O4 , under conditions typical to operating nuclear pressurized water nuclear reactors. Analyses of temperature and pH dependence of the defect formation energies indicate that B can accumulate in NiFe2O4 as an interstitial impurity and may therefore be a major contributor to the anomalous axial power shift observed in nuclear reactors. This computational approach is quite general and applicable to a large variety of solids in equilibrium with aqueous solutions.

  1. Removal of mercury (II) from aqueous solution using papain immobilized on alginate bead: optimization of immobilization condition and modeling of removal study.

    PubMed

    Bhattacharyya, Aparupa; Dutta, Susmita; De, Parameswar; Ray, Parthasarathi; Basu, Srabanti

    2010-12-01

    Papain having the characteristics of metal binding ability is immobilized on alginate bead. Design Expert Software (Version 7.1.6) uses Response Surface Methodology (RSM) for statistical designing of operating condition for immobilization of papain on alginate bead considering concentration of papain, concentration of sodium alginate, concentration of calcium chloride and pH as numeric factors and Specific Enzymatic Activity (SEA) of immobilized papain sample as response. Immobilization using 25.96 g/L papain, 20 g/L sodium alginate and 20 g/L calcium chloride at pH 7 gives the desired product as indicated by ANOVA (Analysis of Variance). Three parameters viz., initial concentration of mercury (II), amount of AIP and pH are varied in a systematic manner. Maximum 98.88% removal of mercury (II) has been achieved within 8 min when simulated aqueous solution of mercury (II) with initial concentration of 10mg/L has been contacted with 5 g of AIP at pH 9 and at 35 degrees C in a batch contactor. A mathematical model has been developed and the value of equilibrium constant for binding of mercury (II) with AIP has been found to be 126797.3.

  2. From a Sequential to a Concurrent Reaction in Aqueous Medium: Ruthenium-Catalyzed Allylic Alcohol Isomerization and Asymmetric Bioreduction.

    PubMed

    Ríos-Lombardía, Nicolás; Vidal, Cristian; Liardo, Elisa; Morís, Francisco; García-Álvarez, Joaquín; González-Sabín, Javier

    2016-07-18

    The ruthenium-catalyzed redox isomerization of allylic alcohols was successfully coupled with the enantioselective enzymatic ketone reduction (mediated by KREDs) in a concurrent process in aqueous medium. The overall transformation, formally the asymmetric reduction of allylic alcohols, took place with excellent conversions and enantioselectivities, under mild reaction conditions, employing commercially and readily available catalytic systems, and without external coenzymes or cofactors. Optimization resulted in a multistep approach and a genuine cascade reaction where the metal catalyst and biocatalyst coexist from the beginning.

  3. Myocardial protection with mild hypothermia.

    PubMed

    Tissier, Renaud; Ghaleh, Bijan; Cohen, Michael V; Downey, James M; Berdeaux, Alain

    2012-05-01

    Mild hypothermia, 32-35° C, is very potent at reducing myocardial infarct size in rabbits, dogs, sheep, pigs, and rats. The benefit is directly related to reduction in normothermic ischaemic time, supporting the relevance of early and rapid cooling. The cardioprotective effect of mild hypothermia is not limited to its recognized reduction of infarct size, but also results in conservation of post-ischaemic contractile function, prevention of no-reflow or microvascular obstruction, and ultimately attenuation of left ventricular remodelling. The mechanism of the anti-infarct effect does not appear to be related to diminished energy utilization and metabolic preservation, but rather to survival signalling that involves either the extracellular signal-regulated kinases and/or the Akt/phosphoinositide 3-kinase/mammalian target of rapamycin pathways. Initial clinical trials of hypothermia in patients with ST-segment elevation myocardial infarction were disappointing, probably because cooling was too slow to shorten normothermic ischaemic time appreciably. New approaches to more rapid cooling have recently been described and may soon be available for clinical use. Alternatively, it may be possible to pharmacologically mimic the protection provided by cooling soon after the onset of ischaemia with an activator of mild hypothermia signalling, e.g. extracellular signal-regulated kinase activator, that could be given by emergency medical personnel. Finally, the protection afforded by cooling can be added to that of pre- and post-conditioning because their mechanisms differ. Thus, myocardial salvage might be greatly increased by rapidly cooling patients as soon as possible and then giving a pharmacological post-conditioning agent immediately prior to reperfusion. PMID:22131353

  4. Aqueous Suzuki Coupling Reactions of Basic Nitrogen-Containing Substrates in the Absence of Added Base and Ligand: Observation of High Yields under Acidic Conditions.

    PubMed

    Li, Zhao; Gelbaum, Carol; Fisk, Jason S; Holden, Bruce; Jaganathan, Arvind; Whiteker, Gregory T; Pollet, Pamela; Liotta, Charles L

    2016-09-16

    A series of aqueous heterogeneous Suzuki coupling reactions of substrates containing basic nitrogen centers with phenylboronic acid in the absence of added base and ligand is presented. High yields of products were obtained by employing aryl bromides containing aliphatic 1°, 2°, and 3° amine substituents, and good to high yields were obtained by employing a variety of substituted bromopyridines. In the former series, the pH of the aqueous phase changed from basic to acidic during the course of the reaction, while in the latter series the aqueous phase was on the acidic side of the pH scale throughout the entire course of reaction. A mechanistic interpretation for these observations, which generally preserves the oxo palladium catalytic cycle widely accepted in the literature, is presented. PMID:27559749

  5. Aqueous Suzuki Coupling Reactions of Basic Nitrogen-Containing Substrates in the Absence of Added Base and Ligand: Observation of High Yields under Acidic Conditions.

    PubMed

    Li, Zhao; Gelbaum, Carol; Fisk, Jason S; Holden, Bruce; Jaganathan, Arvind; Whiteker, Gregory T; Pollet, Pamela; Liotta, Charles L

    2016-09-16

    A series of aqueous heterogeneous Suzuki coupling reactions of substrates containing basic nitrogen centers with phenylboronic acid in the absence of added base and ligand is presented. High yields of products were obtained by employing aryl bromides containing aliphatic 1°, 2°, and 3° amine substituents, and good to high yields were obtained by employing a variety of substituted bromopyridines. In the former series, the pH of the aqueous phase changed from basic to acidic during the course of the reaction, while in the latter series the aqueous phase was on the acidic side of the pH scale throughout the entire course of reaction. A mechanistic interpretation for these observations, which generally preserves the oxo palladium catalytic cycle widely accepted in the literature, is presented.

  6. Staudinger ligation towards cyclodextrin dimers in aqueous/organic media. Synthesis, conformations and guest-encapsulation ability

    PubMed Central

    Manouilidou, Malamatenia D; Lazarou, Yannis G; Mavridis, Irene M

    2014-01-01

    Summary β-Cyclodextrin (β-CD) dimers have been prepared using the bioorthogonal Staudinger ligation for the first time. In addition to a known linker, methyl 2-(diphenylphosphanyl)terephthalate, a doubly active linker was specifically developed that enabled connection of two β-CD units in a single step and in aqueous/organic media, under mild conditions and with good yields. A three-carbon spacer between the β-CD torus and the azido group was required for facile dimer formation. The products, as studied by NMR spectroscopy, were found to adopt closed conformations by intramolecular self-inclusion. On the other hand, association via intermolecular binding was also observed in aqueous solution, confirmed by DOSY NMR experiments. Despite self-inclusion, the β-CD cavities were capable of guest encapsulation, as shown by titration experiments: the binding constant with 1-adamantylamine was similar to that of natural β-CD. Theoretical calculations for isolated molecules (PM3 level of theory) and in the presence of solvent [water, PM3(COSMO)] as well as DFT calculations suggested that the compounds prefer to adopt conformations which bring the phenyl groups either inside the β-CD cavity (inclusion) or over its narrow side (vicinal). Thus, Staudinger ligation could be the method of choice for linking CDs exhibiting (i) ease of preparation in aqueous media, in short steps, under mild conditions and in good yields, (ii) satisfactory aqueous solubility and independent binding capacity of the cavities. PMID:24778732

  7. Hexacoordinate Ru-based olefin metathesis catalysts with pH-responsive N-heterocyclic carbene (NHC) and N-donor ligands for ROMP reactions in non-aqueous, aqueous and emulsion conditions.

    PubMed

    Balof, Shawna L; Nix, K Owen; Olliff, Matthew S; Roessler, Sarah E; Saha, Arpita; Müller, Kevin B; Behrens, Ulrich; Valente, Edward J; Schanz, Hans-Jörg

    2015-01-01

    Three new ruthenium alkylidene complexes (PCy3)Cl2(H2ITap)Ru=CHSPh (9), (DMAP)2Cl2(H2ITap)Ru=CHPh (11) and (DMAP)2Cl2(H2ITap)Ru=CHSPh (12) have been synthesized bearing the pH-responsive H2ITap ligand (H2ITap = 1,3-bis(2',6'-dimethyl-4'-dimethylaminophenyl)-4,5-dihydroimidazol-2-ylidene). Catalysts 11 and 12 are additionally ligated by two pH-responsive DMAP ligands. The crystal structure was solved for complex 12 by X-ray diffraction. In organic, neutral solution, the catalysts are capable of performing standard ring-opening metathesis polymerization (ROMP) and ring closing metathesis (RCM) reactions with standard substrates. The ROMP with complex 11 is accelerated in the presence of two equiv of H3PO4, but is reduced as soon as the acid amount increased. The metathesis of phenylthiomethylidene catalysts 9 and 12 is sluggish at room temperature, but their ROMP can be dramatically accelerated at 60 °C. Complexes 11 and 12 are soluble in aqueous acid. They display the ability to perform RCM of diallylmalonic acid (DAMA), however, their conversions are very low amounting only to few turnovers before decomposition. However, both catalysts exhibit outstanding performance in the ROMP of dicyclopentadiene (DCPD) and mixtures of DCPD with cyclooctene (COE) in acidic aqueous microemulsion. With loadings as low as 180 ppm, the catalysts afforded mostly quantitative conversions of these monomers while maintaining the size and shape of the droplets throughout the polymerization process. Furthermore, the coagulate content for all experiments stayed <2%. This represents an unprecedented efficiency in emulsion ROMP based on hydrophilic ruthenium alkylidene complexes.

  8. Hexacoordinate Ru-based olefin metathesis catalysts with pH-responsive N-heterocyclic carbene (NHC) and N-donor ligands for ROMP reactions in non-aqueous, aqueous and emulsion conditions

    PubMed Central

    Balof, Shawna L; Nix, K Owen; Olliff, Matthew S; Roessler, Sarah E; Saha, Arpita; Müller, Kevin B; Behrens, Ulrich; Valente, Edward J

    2015-01-01

    Summary Three new ruthenium alkylidene complexes (PCy3)Cl2(H2ITap)Ru=CHSPh (9), (DMAP)2Cl2(H2ITap)Ru=CHPh (11) and (DMAP)2Cl2(H2ITap)Ru=CHSPh (12) have been synthesized bearing the pH-responsive H2ITap ligand (H2ITap = 1,3-bis(2’,6’-dimethyl-4’-dimethylaminophenyl)-4,5-dihydroimidazol-2-ylidene). Catalysts 11 and 12 are additionally ligated by two pH-responsive DMAP ligands. The crystal structure was solved for complex 12 by X-ray diffraction. In organic, neutral solution, the catalysts are capable of performing standard ring-opening metathesis polymerization (ROMP) and ring closing metathesis (RCM) reactions with standard substrates. The ROMP with complex 11 is accelerated in the presence of two equiv of H3PO4, but is reduced as soon as the acid amount increased. The metathesis of phenylthiomethylidene catalysts 9 and 12 is sluggish at room temperature, but their ROMP can be dramatically accelerated at 60 °C. Complexes 11 and 12 are soluble in aqueous acid. They display the ability to perform RCM of diallylmalonic acid (DAMA), however, their conversions are very low amounting only to few turnovers before decomposition. However, both catalysts exhibit outstanding performance in the ROMP of dicyclopentadiene (DCPD) and mixtures of DCPD with cyclooctene (COE) in acidic aqueous microemulsion. With loadings as low as 180 ppm, the catalysts afforded mostly quantitative conversions of these monomers while maintaining the size and shape of the droplets throughout the polymerization process. Furthermore, the coagulate content for all experiments stayed <2%. This represents an unprecedented efficiency in emulsion ROMP based on hydrophilic ruthenium alkylidene complexes. PMID:26664616

  9. Hexacoordinate Ru-based olefin metathesis catalysts with pH-responsive N-heterocyclic carbene (NHC) and N-donor ligands for ROMP reactions in non-aqueous, aqueous and emulsion conditions.

    PubMed

    Balof, Shawna L; Nix, K Owen; Olliff, Matthew S; Roessler, Sarah E; Saha, Arpita; Müller, Kevin B; Behrens, Ulrich; Valente, Edward J; Schanz, Hans-Jörg

    2015-01-01

    Three new ruthenium alkylidene complexes (PCy3)Cl2(H2ITap)Ru=CHSPh (9), (DMAP)2Cl2(H2ITap)Ru=CHPh (11) and (DMAP)2Cl2(H2ITap)Ru=CHSPh (12) have been synthesized bearing the pH-responsive H2ITap ligand (H2ITap = 1,3-bis(2',6'-dimethyl-4'-dimethylaminophenyl)-4,5-dihydroimidazol-2-ylidene). Catalysts 11 and 12 are additionally ligated by two pH-responsive DMAP ligands. The crystal structure was solved for complex 12 by X-ray diffraction. In organic, neutral solution, the catalysts are capable of performing standard ring-opening metathesis polymerization (ROMP) and ring closing metathesis (RCM) reactions with standard substrates. The ROMP with complex 11 is accelerated in the presence of two equiv of H3PO4, but is reduced as soon as the acid amount increased. The metathesis of phenylthiomethylidene catalysts 9 and 12 is sluggish at room temperature, but their ROMP can be dramatically accelerated at 60 °C. Complexes 11 and 12 are soluble in aqueous acid. They display the ability to perform RCM of diallylmalonic acid (DAMA), however, their conversions are very low amounting only to few turnovers before decomposition. However, both catalysts exhibit outstanding performance in the ROMP of dicyclopentadiene (DCPD) and mixtures of DCPD with cyclooctene (COE) in acidic aqueous microemulsion. With loadings as low as 180 ppm, the catalysts afforded mostly quantitative conversions of these monomers while maintaining the size and shape of the droplets throughout the polymerization process. Furthermore, the coagulate content for all experiments stayed <2%. This represents an unprecedented efficiency in emulsion ROMP based on hydrophilic ruthenium alkylidene complexes. PMID:26664616

  10. Highly dispersed pd catalyst locked in knitting aryl network polymers for Suzuki-Miyaura coupling reactions of aryl chlorides in aqueous media.

    PubMed

    Li, Buyi; Guan, Zhenhong; Wang, Wei; Yang, Xinjia; Hu, Jianglin; Tan, Bien; Li, Tao

    2012-07-01

    Highly dispersed palladium chloride catalysts locked in triphenylphosphine-functionalized knitting aryl network polymers (KAPs) are developed and exhibit excellent activity under mild conditions in the Suzuki-Miyaura cross-coupling reactions of aryl chlorides in aqueous media. This work highlights that the microporous polymers not only play the role of support materials, but also protect the Pd species from aggregation and precipitation, hence, positively effect the catalysis activity.

  11. Silver-Catalyzed Decarboxylative Radical Azidation of Aliphatic Carboxylic Acids in Aqueous Solution.

    PubMed

    Liu, Chao; Wang, Xiaoqing; Li, Zhaodong; Cui, Lei; Li, Chaozhong

    2015-08-12

    We report herein an efficient and general method for the decarboxylative azidation of aliphatic carboxylic acids. Thus, with AgNO3 as the catalyst and K2S2O8 as the oxidant, the reactions of various aliphatic carboxylic acids with tosyl azide or pyridine-3-sulfonyl azide in aqueous CH3CN solution afforded the corresponding alkyl azides under mild conditions. A broad substrate scope and wide functional group compatibility were observed. A radical mechanism is proposed for this site-specific azidation.

  12. Experimental studies of a single-effect absorption refrigerator using aqueous lithium-bromide: Effect of operating condition to system performance

    SciTech Connect

    Aphornratana, Satha; Sriveerakul, Thanarath

    2007-11-15

    This paper describes an experimental investigation of a single-effect absorption using aqueous lithium-bromide as working fluid. A 2 kW cooling capacity experimental refrigerator was tested with various operating temperatures. It was found that the solution circulation ratio (SCR) has a strong effect on the system performance. The measured SCR was 2-5 times greater than the theoretical prediction. This was due to the low performance of the absorber. The use of solution heat exchanger could increase the COP by up to 60%. (author)

  13. Influence of Aqueous-Salt Conditions on the Structure and Dynamics of the Monomeric and Novel Dimeric forms of the Alzheimer s ABeta21-30 protein fragment

    NASA Astrophysics Data System (ADS)

    Smith, Micholas Dean

    The behavior of the Alzheimer's related peptide Abeta is the subject of much study. In typical computational studies the environment local to the peptide is assumed to be pure water; however, in vivo the peptide is found in the extracellular space near the plasma membrane which is rich in ionic species. In this thesis, the hypothesis that the presence of group I/IIA salts will result in increased sampling of disordered structures as well as modify the dynamics of meta-stable structural motifs in the small folding nucleus of the Abeta peptide (Abeta21-30) is examined under a variety of ionic environments and was shown that of the tested salts, CaCl2 (and MgCl2, to a much lesser degree) did increase the propensity for disordered states; while, the group IA salts, KCl and NaCl, had little effect on the secondary structure of the peptide. Further, study of three familial mutations of this peptide region is also performed under aqueous salt-environments to elucidate further mechanistic details of how aqueous salts modify the region's behavior. Finally, as experimental results have highlighted that aggregation rates of the full-length peptide are modified by the presence of CaCl2, this work examines novel dimers states of Abeta21-30 and their stabilities when exposed to CaCl2.

  14. In situ study of mass transfer in aqueous solutions under high pressures via Raman spectroscopy: A new method for the determination of diffusion coefficients of methane in water near hydrate formation conditions

    USGS Publications Warehouse

    Lu, W.J.; Chou, I.-Ming; Burruss, R.C.; Yang, M.Z.

    2006-01-01

    A new method was developed for in situ study of the diffusive transfer of methane in aqueous solution under high pressures near hydrate formation conditions within an optical capillary cell. Time-dependent Raman spectra of the solution at several different spots along the one-dimensional diffusion path were collected and thus the varying composition profile of the solution was monitored. Diffusion coefficients were estimated by the least squares method based on the variations in methane concentration data in space and time in the cell. The measured diffusion coefficients of methane in water at the liquid (L)-vapor (V) stable region and L-V metastable region are close to previously reported values determined at lower pressure and similar temperature. This in situ monitoring method was demonstrated to be suitable for the study of mass transfer in aqueous solution under high pressure and at various temperature conditions and will be applied to the study of nucleation and dissolution kinetics of methane hydrate in a hydrate-water system where the interaction of methane and water would be more complicated than that presented here for the L-V metastable condition. ?? 2006 Society for Applied Spectroscopy.

  15. Effect of the water content on the retention and enantioselectivity of albendazole and fenbendazole sulfoxides using amylose-based chiral stationary phases in organic-aqueous conditions.

    PubMed

    Materazzo, Sabrina; Carradori, Simone; Ferretti, Rosella; Gallinella, Bruno; Secci, Daniela; Cirilli, Roberto

    2014-01-31

    Four commercially available immobilized amylose-derived CSPs (Chiralpak IA-3, Chiralpak ID-3, Chiralpak IE-3 and Chiralpak IF-3) were used in the HPLC analysis of the chiral sulfoxides albendazole (ABZ-SO) and fenbendazole (FBZ-SO) and their in vivo sulfide precursor (ABZ and FBZ) and sulfone metabolite (ABZ-SO2 and FBZ-SO2) under organic-aqueous mode. U-shape retention maps, established by varying the water content in the acetonitrile- and ethanol-water mobile phases, were indicative of two retention mechanisms operating on the same CSP. The dual retention behavior of polysaccharide-based CSPs was exploited to design greener enantioselective and chemoselective separations in a short time frame. The enantiomers of ABZ-SO and FBZ-SO were baseline resolved with water-rich mobile phases (with the main component usually being 50-65% water in acetonitrile) on the IF-3 CSP and ethanol-water 100:5 mixture on the IA-3 and IE-3 CSPs. A simultaneous separation of ABZ (or FBZ), enantiomers of the corresponding sulfoxide and sulfone was achieved on the IA-3 using ethanol-water 100:60 (acetonitrile-water 100:100 for FBZ) as a mobile phase.

  16. Zn(II)-cyclam based chromogenic sensors for recognition of ATP in aqueous solution under physiological conditions and their application as viable staining agents for microorganism.

    PubMed

    Mahato, Prasenjit; Ghosh, Amrita; Mishra, Sanjiv K; Shrivastav, Anupama; Mishra, Sandhya; Das, Amitava

    2011-05-01

    Two chromogenic complexes, L.Zn (where L is (E)-4-((4-(1,4,8,11-tetraazacyclotetradecan-1-ylsulfonyl)phenyl)diazenyl)-N,N-dimethylaniline) and its [2]pseudorotaxane form (α-CD.L.Zn), were found to bind preferentially to adenosine triphosphate (ATP), among all other common anions and biologically important phosphate (AMP, ADP, pyrophosphate, and phosphate) ions in aqueous HEPES buffer medium of pH 7.2. Studies with live cell cultures of prokaryotic microbes revealed that binding of these two reagents to intercellular ATP, produced in situ, could be used in delineating the gram-positive and the gram-negative bacteria. More importantly, these dyes were found to be nontoxic to living microbes (eukaryotes and prokaryotes) and could be used for studying the cell growth dynamics. Binding to these two viable staining agents to intercellular ATP was also confirmed by spectroscopic studies on cell growth in the presence of different respiratory inhibitors that influence the intercellular ATP generation.

  17. Conditions to prepare PPy/Al 2O 3/Al used as a solid-state capacitor from aqueous malic solutions

    NASA Astrophysics Data System (ADS)

    Martins, J. I.; Costa, S. C.; Bazzaoui, M.; Gonçalves, G.; Fortunato, E.; Martins, R.

    The electrosynthesis of polypyrrole (PPy) has been achieved on aluminium in aqueous medium of malic acid by means of cyclic voltammetry, potentiostatic and galvanostatic techniques. Scanning electron microscopy (SEM) and X-ray microanalysis by dispersion energy spectroscopy (EDS) applying on surfaces show that the PPy coating is developed from the metal surface through the cracks of the initial Al 2O 3 layer. Moreover, the results reveal that the homogeneity of the film achieved increases with the time of electropolymerization. A mechanism involving the participation of the supporting electrolyte and the pyrrole (Py) in distinct active sites was proposed based on the linear sweep voltammetry. It is observed for all the applied electrochemical techniques that the pyrrole concentration has to be higher than 0.1 M to allow the polypyrrole electrodeposition in acid medium. Scanning electron microscopy, secondary electrons (SE) and backscattering electrons (BE), shows that the PPy coating obtained in galvanostatic and potentiostatic modes starts with small islands at weak applied potentials or current densities. The corrosion results in 3% NaCl medium show that the PPy coating decreases the corrosion behaviour of the aluminium. The bilayer Al 2O 3/PPy shows a capacitor with future applications.

  18. Mars aqueous chemistry experiment

    NASA Technical Reports Server (NTRS)

    Clark, Benton C.; Mason, Larry W.

    1993-01-01

    The Mars Aqueous Chemistry Experiment (MACE) is designed to conduct a variety of measurements on regolith samples, encompassing mineral phase analyses, chemical interactions with H2O, and physical properties determinations. From these data, much can be learned or inferred regarding the past weathering environment, the contemporaneous soil micro-environments, and the general chemical and physical state of the Martian regolith. By analyzing both soil and duricrust samples, the nature of the latter may become more apparent. Sites may be characterized for comparative purposes and criteria could be set for selection of high priority materials on future sample return missions. Progress for the first year MACE PIDDP is reported in two major areas of effort: (1) fluids handling concepts, definition, and breadboard fabrication and (2) aqueous chemistry ion sensing technology and test facility integration. A fluids handling breadboard was designed, fabricated, and tested at Mars ambient pressure. The breadboard allows fluid manipulation scenarios to be tested under the reduced pressure conditions expected in the Martian atmosphere in order to validate valve operations, orchestrate analysis sequences, investigate sealing integrity, and to demonstrate efficacy of the fluid handling concept. Additional fluid manipulation concepts have also been developed based on updated MESUR spacecraft definition. The Mars Aqueous Chemistry Experiment Ion Selective Electrode (ISE) facility was designed as a test bed to develop a multifunction interface for measurements of chemical ion concentrations in aqueous solution. The interface allows acquisition of real time data concerning the kinetics and heats of salt dissolution, and transient response to calibration and solubility events. An array of ion selective electrodes has been interfaced and preliminary calibration studies performed.

  19. Hematite Spherules in Basaltic Tephra Altered Under Aqueous, Acid-Sulfate Conditions on Mauna Kea Volcano, Hawaii: Possible Clues for the Occurrence of Hematite-Rich Spherules in the Burns Formation at Meridiani Planum, Mars

    NASA Technical Reports Server (NTRS)

    Morris, R. V.; Ming, D. W.; Graff, T. G.; Arvidson, R. E.; Bell, J. F., III; Squyres, S. W.; Mertzman, S. A.; Gruener, J. E.; Golden, D. C.; Robinson, G. A.

    2005-01-01

    Iron-rich spherules (>90% Fe2O3 from electron microprobe analyses) approx.10-100 microns in diameter are found within sulfate-rich rocks formed by aqueous, acid-sulfate alteration of basaltic tephra on Mauna Kea volcano, Hawaii. Although some spherules are nearly pure Fe, most have two concentric compositional zones, with the core having a higher Fe/Al ratio than the rim. Oxide totals less than 100% (93-99%) suggest structural H2O and/or /OH. The transmission Moessbauer spectrum of a spherule-rich separate is dominated by a hematite (alpha-Fe2O3) sextet whose peaks are skewed toward zero velocity. Skewing is consistent with Al(3+) for Fe(3+) substitution and structural H2O and/or /OH. The grey color of the spherules implies specular hematite. Whole-rock powder X-ray diffraction spectra are dominated by peaks from smectite and the hydroxy sulfate mineral natroalunite as alteration products and plagioclase feldspar that was present in the precursor basaltic tephra. Whether spherule formation proceeded directly from basaltic material in one event (dissolution of basaltic material and precipitation of hematite spherules) or whether spherule formation required more than one event (formation of Fe-bearing sulfate rock and subsequent hydrolysis to hematite) is not currently constrained. By analogy, a formation pathway for the hematite spherules in sulfate-rich outcrops at Meridiani Planum on Mars (the Burns formation) is aqueous alteration of basaltic precursor material under acid-sulfate conditions. Although hydrothermal conditions are present on Mauna Kea, such conditions may not be required for spherule formation on Mars if the time interval for hydrolysis at lower temperatures is sufficiently long.

  20. Thermal behavior of aqueous iron oxide nano-fluid as a coolant on a flat disc heater under the pool boiling condition

    NASA Astrophysics Data System (ADS)

    Salari, E.; Peyghambarzadeh, S. M.; Sarafraz, M. M.; Hormozi, F.; Nikkhah, V.

    2016-04-01

    This paper experimentally focuses on the pool boiling heat transfer characteristics of gamma Fe3O4 aqueous nano-fluids on a flat disc heater. The nano-fluid used in this research was prepared using two-step method and was stabilized using nonylphenol ethoxylate nonionic surfactant, pH setting, and sonication process as well. Influence of different operating parameters such as heat flux (0-1546 kW/m2), mass concentration of nano-fluids (weight concentration 0.1-0.3 %), bubble formation, critical heat flux (1170 kW/m2 for water, 1230 kW/m2 (wt% = 0.1), 1320 kW/m2 (wt% = 0.2), 1450 kW/m2 (wt% = 0.3) and fouling on pool boiling heat transfer coefficient of nano-fluid as a thermal performance index were experimentally investigated and briefly discussed. Results demonstrated that the pool boiling heat transfer coefficient increases with increasing the mass concentration and the applied heat flux. In addition, the rate of bubble formation is significantly intensified at higher heat fluxes and subsequently, larger bubbles detach the surface due to the intensification of bubble coalescence. In terms of fouling formation, it can be stated that fouling of nano-fluids is a strong function of time and rate of deposition is increased over the extended time while the pool boiling heat transfer coefficient was not decreased over the time, as porous deposited layer on the surface are detached from the surface by bubble interactions. In terms of critical heat flux, capillary action of the deposited layer was found to be the main reason responsible for increasing the critical heat flux as liquid is stored inside the porous deposited layer, which enhances the surface toleration against the critical heat flux crisis.

  1. Enantioselective Synthesis of N-PMP-1,2-dihydropyridines via Formal [4 + 2] Cycloaddition between Aqueous Glutaraldehyde and Imines.

    PubMed

    Ramaraju, Panduga; Mir, Nisar A; Singh, Deepika; Gupta, Vivek K; Kant, Rajni; Kumar, Indresh

    2015-11-20

    A simple and highly practical one-pot formal [4 + 2] cycloaddition approach for the enantioselective synthesis of N-PMP-1,2-dihydropyridines (DHPs) is described. This chemistry involves an amino-catalytic direct Mannich reaction/cyclization followed by IBX-mediated chemo- and regioselective oxidation sequence between readily available aqueous glutaraldehyde and imines under very mild conditions. A series of N-PMP-1,2-DHPs have been prepared in high yields and excellent enantioselectivity. This method also gives access to both enantiomers of 1,2-DHPs in surplus amount by shifting the catalyst configuration.

  2. From a Sequential to a Concurrent Reaction in Aqueous Medium: Ruthenium-Catalyzed Allylic Alcohol Isomerization and Asymmetric Bioreduction.

    PubMed

    Ríos-Lombardía, Nicolás; Vidal, Cristian; Liardo, Elisa; Morís, Francisco; García-Álvarez, Joaquín; González-Sabín, Javier

    2016-07-18

    The ruthenium-catalyzed redox isomerization of allylic alcohols was successfully coupled with the enantioselective enzymatic ketone reduction (mediated by KREDs) in a concurrent process in aqueous medium. The overall transformation, formally the asymmetric reduction of allylic alcohols, took place with excellent conversions and enantioselectivities, under mild reaction conditions, employing commercially and readily available catalytic systems, and without external coenzymes or cofactors. Optimization resulted in a multistep approach and a genuine cascade reaction where the metal catalyst and biocatalyst coexist from the beginning. PMID:27258838

  3. Chemo-, Regio-, and Stereoselective Copper(II)-Catalyzed Boron Addition to Acetylenic Esters and Amides in Aqueous Media.

    PubMed

    Nelson, Amanda K; Peck, Cheryl L; Rafferty, Sean M; Santos, Webster L

    2016-05-20

    Aqueous conditions were developed for conducting an open-to-air, copper(II)-catalyzed addition of pinBBdan to alkynoates and alkynamides. The simple and mild β-borylation protocol proceeds in a remarkably chemo-, regio-, and stereoselective fashion to afford 1,8-diaminonaphthalene protected (Z)-β-boryl enoates and primary, secondary, and tertiary enamides in good to excellent yields. These reactions demonstrate a high tolerance toward a variety of alkyl, aryl, and heteroatom functional groups and provide convenient access to a diverse range of vinylboronic acid derivatives. PMID:27104638

  4. Anthemis xylopoda flowers aqueous extract assisted in situ green synthesis of Cu nanoparticles supported on natural Natrolite zeolite for N-formylation of amines at room temperature under environmentally benign reaction conditions.

    PubMed

    Nasrollahzadeh, Mahmoud; Sajadi, S Mohammad; Hatamifard, Arezo

    2015-12-15

    Zeolites, which are nontoxic, abundant, and cheap, are very promising supports for the design and preparation of new and environmentally benign catalysts. In this study, Cu nanoparticles (NPs) were immobilized on the surface of natural Natrolite zeolite by Anthemis xylopoda flowers aqueous extract as a reducing and stabilizing agent. Afterward, the catalytic performance of the prepared catalyst was investigated for N-formylation of amines at room temperature under environmentally benign reaction conditions. The catalyst could be reused at least 5 times without any decrease in activity. The advantages of the present protocol include the use of green catalyst, easy isolation of the products, reusability of catalyst, absence of nontoxic reagents, and excellent yield of the products.

  5. Aqueous foam toxicology evaluation and hazard review

    SciTech Connect

    Archuleta, M.M.

    1995-10-01

    Aqueous foams are aggregates of bubbles mechanically generated by passing air or other gases through a net, screen, or other porous medium that is wetted by an aqueous solution of surface-active foaming agents (surfactants). Aqueous foams are important in modem fire-fighting technology, as well as for military uses for area denial and riot or crowd control. An aqueous foam is currently being developed and evaluated by Sandia National Laboratories (SNL) as a Less-Than-Lethal Weapon for the National Institute of Justice (NIJ). The purpose of this study is to evaluate the toxicity of the aqueous foam developed for the NIJ and to determine whether there are any significant adverse health effects associated with completely immersing individuals without protective equipment in the foam. The toxicity of the aqueous foam formulation developed for NIJ is determined by evaluating the toxicity of the individual components of the foam. The foam is made from a 2--5% solution of Steol CA-330 surfactant in water generated at expansion ratios ranging from 500:1 to 1000:1. SteoI CA-330 is a 35% ammonium laureth sulfate in water and is produced by Stepan Chemical Company and containing trace amounts (<0.1%) of 1,4-dioxane. The results of this study indicate that Steol CA-330 is a non-toxic, mildly irritating, surfactant that is used extensively in the cosmetics industry for hair care and bath products. Inhalation or dermal exposure to this material in aqueous foam is not expected to produce significant irritation or systemic toxicity to exposed individuals, even after prolonged exposure. The amount of 1,4-dioxane in the surfactant, and subsequently in the foam, is negligible and therefore, the toxicity associated with dioxane exposure is not significant. In general, immersion in similar aqueous foams has not resulted in acute, immediately life-threatening effects, or chronic, long-term, non-reversible effects following exposure.

  6. "White Privilege": A Mild Critique

    ERIC Educational Resources Information Center

    Blum, Lawrence

    2008-01-01

    White privilege analysis has been influential in philosophy of education. I offer some mild criticisms of this largely salutary direction--its inadequate exploration of its own normative foundations, and failure to distinguish between "spared injustice", "unjust enrichment" and "non-injustice-related" privileges; its inadequate exploration of the…

  7. Educating Students with Mild Disabilities.

    ERIC Educational Resources Information Center

    Meyen, Edward L., Ed.; And Others

    The book contains 19 papers from the journal, "Focus on Exceptional Children," that discuss new perspectives and practices in educating students with mild disabilities. The first half of the book is titled "New Perspectives" and includes the following articles: "Beyond the Regular Education Initiative/Inclusion and the Resource Room Controversy"…

  8. In-situ observation of a dendrite growth in an aqueous condition and a uranium deposition into a liquid cadmium cathode in an electrowinning system

    NASA Astrophysics Data System (ADS)

    Kim, Si-Hyung; Yoon, Dal-Seong; You, Young-Jae; Paek, Seungwoo; Shim, Joon-Bo; Kwon, Sang-Woon; Kim, Kwang-Rag; Chung, Hong-Suk; Ahn, Do-Hee; Lee, Han-Soo

    2009-03-01

    A zinc-gallium system was setup to observe the growth process of dendrites and to compare the performance of the stirrers which would prevent a dendrite formation. In a no-stirring condition, zinc was easily deposited on a liquid gallium cathode in the form of dendrites. It was difficult for a paddle stirrer to directly fracture the zinc dendrites to fine particles. However, a harrow stirrer was observed to fracture the dendrite to some extent at high speeds. Not only their rotation speed but also the length of their blades needed to be properly adjusted to enhance their performance. In the uranium-cadmium experiment, the diffusion coefficient of the uranium species was obtained by the cyclic voltammetry method, which is around 1 × 10 -5 cm 2/s. In a no-stirring condition, most of the uranium deposited at the current densities of 35, 100 and 200 mA/cm 2 did not sink into the liquid cadmium cathode.

  9. Reaction mechanism for the aqueous-phase mineral carbonation of heat-activated serpentine at low temperatures and pressures in flue gas conditions.

    PubMed

    Pasquier, Louis-César; Mercier, Guy; Blais, Jean-François; Cecchi, Emmanuelle; Kentish, Sandra

    2014-05-01

    Mineral carbonation is known as one of the safest ways to sequester CO2. Nevertheless, the slow kinetics and low carbonation rates constitute a major barrier for any possible industrial application. To date, no studies have focused on reacting serpentinite with a relatively low partial pressure of CO2 (pCO2) close to flue gas conditions. In this work, finely ground and heat-treated serpentinite [Mg3Si2O5(OH)4] extracted from mining residues was reacted with a 18.2 vol % CO2 gas stream at moderate global pressures to investigate the effect on CO2 solubility and Mg leaching. Serpentinite dissolution rates were also measured to define the rate-limiting step. Successive batches of gas were contacted with the same serpentinite to identify surface-limiting factors using scanning electron microscopy (SEM) analysis. Investigation of the serpentinite carbonation reaction mechanisms under conditions close to a direct flue gas treatment showed that increased dissolution rates could be achieved relative to prior work, with an average Mg dissolution rate of 3.55 × 10(-11) mol cm(-2) s(-1). This study provides another perspective of the feasibility of applying a mineral carbonation process to reduce industrial greenhouse gas (GHG) emissions from large emission sources.

  10. Removal of aqueous rinsable flux residues in a batch spray dishwater

    SciTech Connect

    Slanina, J.T.

    1992-02-01

    An alkaline detergent solution used in an industrial dishwasher was evaluated to remove aqueous rinsable flux residues on printed wiring boards (PWBs) after hot air solder leveling and hot oil solder dip and leveling. The dishwasher, a batch cleaning process, was compared to an existing conveyorized aqueous cleaning process. The aqueous soluble flux residues from both soldering processes were removed with a solution of a mild alkaline detergent dissolved in hot deionized (DI) water.

  11. Amphoteric Aqueous Hafnium Cluster Chemistry.

    PubMed

    Goberna-Ferrón, Sara; Park, Deok-Hie; Amador, Jenn M; Keszler, Douglas A; Nyman, May

    2016-05-17

    Selective dissolution of hafnium-peroxo-sulfate films in aqueous tetramethylammonium hydroxide enables extreme UV lithographic patterning of sub-10 nm HfO2 structures. Hafnium speciation under these basic conditions (pH>10), however, is unknown, as studies of hafnium aqueous chemistry have been limited to acid. Here, we report synthesis, crystal growth, and structural characterization of the first polynuclear hydroxo hafnium cluster isolated from base, [TMA]6 [Hf6 (μ-O2 )6 (μ-OH)6 (OH)12 ]⋅38 H2 O. The solution behavior of the cluster, including supramolecular assembly via hydrogen bonding is detailed via small-angle X-ray scattering (SAXS) and electrospray ionization mass spectrometry (ESI-MS). The study opens a new chapter in the aqueous chemistry of hafnium, exemplifying the concept of amphoteric clusters and informing a critical process in single-digit-nm lithography.

  12. Syntheses of the Water-Dispersible Glycolic Acid Capped ZnS:Mn Nanocrystals at Different pH Conditions, and Their Aggregation and Luminescence Quenching Effects in Aqueous Solution.

    PubMed

    Sim, Yu Jin; Hwang, Cheong-Soo

    2016-06-01

    Water-dispersible ZnS:Mn nanocrystals were prepared by capping their surface with polar glycolic acid molecules at three different pH conditions. The produced ZnS:Mn-GA nanocrystals were characterized by XRD, HR-TEM, ICP-AES, and FT-IR spectroscopy. The optical properties were also measured by UV-Visible and room temperature photoluminescence (PL) spectroscopy. In the PL spectra, theses ZnS:Mn-GA nanocrystals showed broad emission peaks around 595 nm, and the calculated relative quantum efficiencies against an organic dye standard were in the range from 2.16 to 5.52%. The measured particle size from the HR-TEM images was about 3.7 nm on average, which were also supported by the calculations with the Debye-Scherrer methods. In addition, the surface charges of the nanocrystals were determined by an electrophoretic method, which showed pH dependent charge values of the nanocrytals: +0.88 mV (pH 2), +0.82 mV (pH 7), and -0.59 mV (pH 12) respectively. In addition, the degrees of aggregation of the nanocrystals in aqueous solutions were determined by a hydrodynamic light scattering method. As a result, formations of micrometer size agglomerates for all the ZnS:Mn-GA nanocrystals in water was observed at room temperature. This was probably caused by intermolecular attraction between the capping molecules. In addition, the ZnS:Mn-GA with the negative surface charge was presumed to be suitable for further coordination to a transition metal ion on the surface of the nanocrystal. As a result, fast luminescence quenching was observed after addition of aqueous solution containing Cu2+ ions.

  13. Syntheses of the Water-Dispersible Glycolic Acid Capped ZnS:Mn Nanocrystals at Different pH Conditions, and Their Aggregation and Luminescence Quenching Effects in Aqueous Solution.

    PubMed

    Sim, Yu Jin; Hwang, Cheong-Soo

    2016-06-01

    Water-dispersible ZnS:Mn nanocrystals were prepared by capping their surface with polar glycolic acid molecules at three different pH conditions. The produced ZnS:Mn-GA nanocrystals were characterized by XRD, HR-TEM, ICP-AES, and FT-IR spectroscopy. The optical properties were also measured by UV-Visible and room temperature photoluminescence (PL) spectroscopy. In the PL spectra, theses ZnS:Mn-GA nanocrystals showed broad emission peaks around 595 nm, and the calculated relative quantum efficiencies against an organic dye standard were in the range from 2.16 to 5.52%. The measured particle size from the HR-TEM images was about 3.7 nm on average, which were also supported by the calculations with the Debye-Scherrer methods. In addition, the surface charges of the nanocrystals were determined by an electrophoretic method, which showed pH dependent charge values of the nanocrytals: +0.88 mV (pH 2), +0.82 mV (pH 7), and -0.59 mV (pH 12) respectively. In addition, the degrees of aggregation of the nanocrystals in aqueous solutions were determined by a hydrodynamic light scattering method. As a result, formations of micrometer size agglomerates for all the ZnS:Mn-GA nanocrystals in water was observed at room temperature. This was probably caused by intermolecular attraction between the capping molecules. In addition, the ZnS:Mn-GA with the negative surface charge was presumed to be suitable for further coordination to a transition metal ion on the surface of the nanocrystal. As a result, fast luminescence quenching was observed after addition of aqueous solution containing Cu2+ ions. PMID:27427703

  14. Tannin bark Melalauca cajuputi powell (gelam) as green corrosion inhibitor of mild steel

    NASA Astrophysics Data System (ADS)

    Talib, Nur Atiqah Abu; Zakaria, Sarani; Hua, Chia Chin; Othman, Norinsan Kamil

    2014-09-01

    Tannin was extracted from gelam bark and used to produce corrosion inhibitor for mild steel. Tannin was extracted from gelam bark using 70% aqueous acetone for 6 hour. Tannin powder was characterization using fourier transform infrared spectroscopy to analyse chemical component in tannin and Scanning electron microscope (SEM) for tannin physical structure. The tannin effect on the corrosion inhibition of mild steel has been investigated in 1Mol HCl solution for 6 hour followed ASTM. The weight loss method were applied to study the mild steel corrosion behavior in the present and absend of different concentration of tannin (250, 300, 350)ppm. Tannin act good inhibitor as corrosion inhibitor for mild steel in acid medium. Surface morphology of carbon steel with and without inhibitor was investigated by scanning electron microscopy.

  15. Tannin bark Melalauca cajuputi powell (gelam) as green corrosion inhibitor of mild steel

    SciTech Connect

    Talib, Nur Atiqah Abu; Zakaria, Sarani; Hua, Chia Chin; Othman, Norinsan Kamil

    2014-09-03

    Tannin was extracted from gelam bark and used to produce corrosion inhibitor for mild steel. Tannin was extracted from gelam bark using 70% aqueous acetone for 6 hour. Tannin powder was characterization using fourier transform infrared spectroscopy to analyse chemical component in tannin and Scanning electron microscope (SEM) for tannin physical structure. The tannin effect on the corrosion inhibition of mild steel has been investigated in 1Mol HCl solution for 6 hour followed ASTM. The weight loss method were applied to study the mild steel corrosion behavior in the present and absend of different concentration of tannin (250, 300, 350)ppm. Tannin act good inhibitor as corrosion inhibitor for mild steel in acid medium. Surface morphology of carbon steel with and without inhibitor was investigated by scanning electron microscopy.

  16. Development of mild gasification process

    SciTech Connect

    Chu, C.I.C.; Gillespie, B.L.

    1987-11-01

    Under a previous contract with Morgantown Energy Technology Center (METC), Department of Energy (DOE) Contract No. AC21-84MC21108, UCC Research Corporation (UCCRC) built and tested a 1500 lb/day Mild Gasification Process Development Unit (MGU). The MGU, as tested under the previous contract, is shown in Figure 1. Testing completed under the previous contract showed that good quality hydrocarbon liquids and good quality char can be produced in the MGU. However, the MGU is not optimized. The primary objectives of the current project are to optimize the MGU and determine the suitability of char for several commercial applications. The program consists of four tasks; Task 1 -- Test Plan; Task 2 -- Optimization of Mild Gasification Process; Task 3 -- Evaluation of Char and Char/Coal Blends as a Boiler/Blast Furnace Fuel; and Task 4 -- Analysis of Data and Preparation of Final Report. Task 1 has been completed while work continued on Task 2.

  17. Development of mild gasification process

    SciTech Connect

    Chu, C.I.C.; Gillespie, B.L.

    1988-02-01

    Under a previous contract with Morgantown Energy Technology Center (METC), Department of Energy (DOE) Contract No. DE-AC21-84MC21108, UCC Research Corporation (UCCRC) built and tested a 1500 lb/day Mild Gasification Process Development Unit (MGU). The MGU, as tested under the previous contract, is shown in Figure 1. Testing completed under the previous contract showed that good quality hydrocarbon liquids and good quality char can be produced in the MGU. However, the MGU is not optimized. The primary objectives of the current project are to optimize the MGU and determine the suitability of char for several commercial applications. The program consists of four tasks; Task 1-Test Plan; Task 2-Optimization of Mild Gasification Process; Task 3-Evaluation of Char and Char/Coal Blends as a Boiler/Blast Furnace Fuel; and Task 4-Analysis of Data and Preparation of Final Report. Task 1 has been completed while work continued on Task 2.

  18. Development of mild gasification process

    SciTech Connect

    Chu, C.I.C.; Derting, T.M.

    1988-07-01

    Under a previous contract with Morgantown Energy Technology Center (METC), Department of Energy (DOE) Contract No. AC21-84MC21108, UCC Research Corporation (UCCRC) built and tested a 1500 lb/day Mild Gasification Process Development Unit (MGU). The MGU, as tested under the previous contract, is shown in Figure 1. Testing completed under the previous contract showed that good quality hydrocarbon liquids and good quality char can be produced in the MGU. However, the MGU is not optimized. The primary objectives of the current project are to optimize the MGU and determine the suitability of char for several commercial applications. The program consists of four tasks; Task 1 -- Test Plan; Task 2 -- Optimization of Mild Gasification Process; Task 3 -- Evaluation of Char and Char/Coal Blends as a Boiler/Blast Furnace Fuel; and Task 4 -- Analysis of Data and Preparation of Final Report. Task 1 has been completed while work continued on Task 2.

  19. Development of mild gasification process

    SciTech Connect

    Chu, C.I.C.; Williams, S.W.

    1989-01-01

    Under a previous contract with Morgantown Energy Technology Center (METC), Department of Energy (DOE) Contract No. AC21-84MC21108, UCC Research Corporation (UCCRC) built and tested a 1500 lb/day Mild Gasification Process Development Unit (MGU). The MGU, as tested under the previous contract, is shown in Figure 1. Testing completed under the previous contract showed that good quality hydrocarbon liquids and good quality char can be produced in the MGU. However, the MGU is not optimized. The primary objectives of the current project are to optimize the MGU and determine the suitability of char for several commercial applications. The program consists of four tasks; Task 1 -- Test Plan; Task 2 -- Optimization of Mild Gasification Process; Task 3 -- Evaluation of Char and Char/Coal Blends as a Boiler/Blast Furnace Fuel; and Task 4 -- Analysis of Data and Preparation of Final Report. Task 1 has been completed while work continued on Task 2.

  20. Inclusion complexation of novocaine by beta-cyclodextrin in aqueous solutions.

    PubMed

    Iglesias, Emilia

    2006-06-01

    The formation of inclusion complexes between beta-cyclodextrin (beta-CD) and the local anesthetic 2-(diethylamino)ethyl-p-amino-benzoate (novocaine) in aqueous solutions under different acidity conditions, using steady-state fluorescence or UV-vis spectroscopies, electrical conductivity, or the kinetic study of both the nitrosation reaction of the primary amine group in a mild acid medium and the hydrolysis of the ester function under an alkaline medium, has been studied. The inclusion complex formation between neutral or protonated novocaine and beta-CD of 1:1 stoichiometry was observed; however, the magnitude of the binding constants depends on the nature of both the guest and the host, and the higher-affinity guest-host was found under conditions when both the novocaine and the beta-CD were neutral molecules.

  1. Mukaiyama Aldol Reactions in Aqueous Media

    PubMed Central

    Kitanosono, Taku; Kobayashi, Shū

    2013-01-01

    Mukaiyama aldol reactions in aqueous media have been surveyed. While the original Mukaiyama aldol reactions entailed stoichiometric use of Lewis acids in organic solvents under strictly anhydrous conditions, Mukaiyama aldol reactions in aqueous media are not only suitable for green sustainable chemistry but are found to produce singular phenomena. These findings led to the discovery of a series of water-compatible Lewis acids such as lanthanide triflates in 1991. Our understanding on these beneficial effects in the presence of water will be deepened through the brilliant examples collected in this review. 1 Introduction 2 Rate Enhancement by Water in the Mukaiyama Aldol Reaction 3 Lewis Acid Catalysis in Aqueous or Organic Solvents 3.1 Water-Compatible Lewis Acids 4 Lewis-Base Catalysis in Aqueous or Organic Solvents 5 The Mukaiyama Aldol Reactions in 100% Water 6 Asymmetric Catalysts in Aqueous Media and Water 7 Conclusions and Perspective PMID:24971045

  2. A mild, catalyst-free synthesis of 2-aminopyridines

    PubMed Central

    Poola, Bhaskar; Choung, Wonken; Nantz, Michael H.

    2014-01-01

    Alkylation of 2-mercaptopyridine with 1,2-dibromoethane affords a cyclic dihydrothiazolopyridinium salt that can serve as a precursor of 2-aminopyridines. Its reaction with primary or secondary amines, either neat or in DMSO, under mild conditions gives the title compounds. PMID:25165405

  3. Music Enhances Autobiographical Memory in Mild Alzheimer's Disease

    ERIC Educational Resources Information Center

    El Haj, Mohamad; Postal, Virginie; Allain, Philippe

    2012-01-01

    Studies have shown that the "Four Seasons" music may enhance the autobiographical performance of Alzheimer's disease (AD) patients. We used a repeated measures design in which autobiographical recall of 12 mild AD patients was assessed using a free narrative method under three conditions: (a) in "Silence," (b) after being exposed to the opus "Four…

  4. Cholinergic Enhancement of Frontal Lobe Activity in Mild Cognitive Impairment

    ERIC Educational Resources Information Center

    Saykin, Andrew J.; Wishart, Heather A.; Rabin, Laura A.; Flashman, Laura A.; McHugh, Tara L.; Mamourian, Alexander C.; Santulli, Robert B.

    2004-01-01

    Cholinesterase inhibitors positively affect cognition in Alzheimer's disease (AD) and other conditions, but no controlled functional MRI studies have examined where their effects occur in the brain. We examined the effects of donepezil hydrochloride (Aricept[Registered sign]) on cognition and brain activity in patients with amnestic mild cognitive…

  5. Some aspects of the aqueous solution chemistry of the Na+/Ca2+/OH-/Cit3- system: The structure of a new calcium citrate complex forming under hyperalkaline conditions

    NASA Astrophysics Data System (ADS)

    Gácsi, Attila; Kutus, Bence; Buckó, Ákos; Csendes, Zita; Peintler, Gábor; Pálinkó, István; Sipos, Pál

    2016-08-01

    In the present study, we show that in hyperalkaline (pH > 13) aqueous solutions, Ca2+ forms a new, so far unknown complex species with the citrate ion, the structure of which is different from the well-known CaCit-(aq) species present in solutions of close to neutral pH. The solubility of Ca3Cit2(s) was found to increase significantly under hyperalkaline conditions. The decrease in the electric conductivity and the variations observed in the freezing point depression of such solutions also indicate complexation. From 1H NMR measurements, in this complex, the citrate ion is suggested to be in quadruply deprotonated form. From the variation of the 2JHH geminal proton coupling constant, two neighboring carboxylate groups are coordinated to the calcium ion in a monodentate mode (besides the alcoholate). The optimal structure of the complex with the composition of CaCitH-12-(aq) has also been calculated using DFT calculations, applying the Polarizable Continuum Model. Sodium ion-pairing was found to compete efficiently with this calcium complexation process, and in solutions with high Na-ion content, the equilibria are shifted towards the formation of NaCit2-(aq) and Na2Cit-(aq) ion pairs.

  6. Ca(OH)2-Catalyzed Condensation of Aldehydes with Methyl ketones in Dilute Aqueous Ethanol: A Comprehensive Access to α,β-Unsaturated Ketones

    PubMed Central

    Yu, Lei; Han, Mengting; Luan, Jie; Xu, Lin; Ding, Yuanhua; Xu, Qing

    2016-01-01

    Cheap, abundant but seldom-employed Ca(OH)2 was found to be an excellent low-loading (5–10 mol%) catalyst for Claisen-Schmidt condensation of aldehydes with methyl ketones under mild conditions. It was interesting that dilute aqueous ethanol (20 v/v%) was unexpectedly discovered to be the optimal solvent. The reaction was scalable at least to 100 mmol and calcium could be precipitated by CO2 and removed by filtration. Evaporation of solvent directly afforded the product in the excellent 96% yield with high purity, as confirmed by its 1H NMR spectrum. PMID:27443482

  7. Ca(OH)2-Catalyzed Condensation of Aldehydes with Methyl ketones in Dilute Aqueous Ethanol: A Comprehensive Access to α,β-Unsaturated Ketones

    NASA Astrophysics Data System (ADS)

    Yu, Lei; Han, Mengting; Luan, Jie; Xu, Lin; Ding, Yuanhua; Xu, Qing

    2016-07-01

    Cheap, abundant but seldom-employed Ca(OH)2 was found to be an excellent low-loading (5-10 mol%) catalyst for Claisen-Schmidt condensation of aldehydes with methyl ketones under mild conditions. It was interesting that dilute aqueous ethanol (20 v/v%) was unexpectedly discovered to be the optimal solvent. The reaction was scalable at least to 100 mmol and calcium could be precipitated by CO2 and removed by filtration. Evaporation of solvent directly afforded the product in the excellent 96% yield with high purity, as confirmed by its 1H NMR spectrum.

  8. Ca(OH)2-Catalyzed Condensation of Aldehydes with Methyl ketones in Dilute Aqueous Ethanol: A Comprehensive Access to α,β-Unsaturated Ketones

    NASA Astrophysics Data System (ADS)

    Yu, Lei; Han, Mengting; Luan, Jie; Xu, Lin; Ding, Yuanhua; Xu, Qing

    2016-07-01

    Cheap, abundant but seldom-employed Ca(OH)2 was found to be an excellent low-loading (5–10 mol%) catalyst for Claisen-Schmidt condensation of aldehydes with methyl ketones under mild conditions. It was interesting that dilute aqueous ethanol (20 v/v%) was unexpectedly discovered to be the optimal solvent. The reaction was scalable at least to 100 mmol and calcium could be precipitated by CO2 and removed by filtration. Evaporation of solvent directly afforded the product in the excellent 96% yield with high purity, as confirmed by its 1H NMR spectrum.

  9. Coeval Formation of Aqueous Minerals on Mars

    NASA Astrophysics Data System (ADS)

    Fairen, A.; Uceda, E.; Gil, C.; Palmero Rodriguez, A.; Gago-Duport, L.

    2015-12-01

    Understanding the geochemical conditions on early Mars requires an explanation for the presence of sulfates and phyllosilicates, which must be also consistent with the absence of widespread sedimentary carbonates. In addition, sulfates and phyllosilicates do not generally occur together on Mars, which has been interpreted as a marker for detached mineral formation due to differing planetary environmental conditions separated dramatically, either in time or in space. Here, thermodynamic equilibrium calculations are used to determine the stability boundaries for phyllosilicates, ferrous and ferric sulfates, carbonates and iron oxyhydroxides precipitation on early Mars, at different atmospheric CO2 pressures and both under reducing and oxidizing conditions. Results suggest that phyllosilicates formed in mildly acidic to alkaline aqueous solutions, with a pH>4 for nontronite and a pH>6 for other smectites with low content in Fe and Mg (montmorillonite, saponite). Sulfate deposition dominates in solutions moderately to highly acidic, with a pH<6 conducive to the synthesis of kieserite. In the overlapping phyllosilicates/sulfates pH range, between 4 and 6, a competition for Mg between nontronite and kieserite is expected, and the formation of nontronite would be favored in areas where SiO2 activity in surface waters was high as a result of intense weathering of the early basaltic crust. Carbonates formed at pH>6, overlapping with the synthesis of low-Fe-Mg smectites. Model calculations anticipate the co-precipitation of smectites and siderite or any alteration product that could have resulted from the later substitution of Fe in siderite, such as Mg- or Mn-carbonate, triggering a competition for Mg between magnesite and low-Fe-Mg smectites. As expected, the model does not predict coeval synthesis of carbonates and sulfates. Goethite and other oxyhydroxides precipitate at pH below 2, a range at which jarosite and goethite are the expected iron-bearing phases. These

  10. Chemical reactions at aqueous interfaces

    NASA Astrophysics Data System (ADS)

    Vecitis, Chad David

    2009-12-01

    Interfaces or phase boundaries are a unique chemical environment relative to individual gas, liquid, or solid phases. Interfacial reaction mechanisms and kinetics are often at variance with homogeneous chemistry due to mass transfer, molecular orientation, and catalytic effects. Aqueous interfaces are a common subject of environmental science and engineering research, and three environmentally relevant aqueous interfaces are investigated in this thesis: 1) fluorochemical sonochemistry (bubble-water), 2) aqueous aerosol ozonation (gas-water droplet), and 3) electrolytic hydrogen production and simultaneous organic oxidation (water-metal/semiconductor). Direct interfacial analysis under environmentally relevant conditions is difficult, since most surface-specific techniques require relatively `extreme' conditions. Thus, the experimental investigations here focus on the development of chemical reactors and analytical techniques for the completion of time/concentration-dependent measurements of reactants and their products. Kinetic modeling, estimations, and/or correlations were used to extract information on interfacially relevant processes. We found that interfacial chemistry was determined to be the rate-limiting step to a subsequent series of relatively fast homogeneous reactions, for example: 1) Pyrolytic cleavage of the ionic headgroup of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) adsorbed to cavitating bubble-water interfaces during sonolysis was the rate-determining step in transformation to their inorganic constituents carbon monoxide, carbon dioxide, and fluoride; 2) ozone oxidation of aqueous iodide to hypoiodous acid at the aerosol-gas interface is the rate-determining step in the oxidation of bromide and chloride to dihalogens; 3) Electrolytic oxidation of anodic titanol surface groups is rate-limiting for the overall oxidation of organics by the dichloride radical. We also found chemistry unique to the interface, for example: 1

  11. Application of a new phosphorus-free palladium heterogeneous nanocatalyst supported on modified MWCNT the highly selective and efficient cleavage of propargyl, allyl, and benzyl phenol ethers under mild conditions.

    PubMed

    Sharghi, Hashem; Khoshnood, Abbas; Khalifeh, Reza; Doroodmand, Mohammad Mehdi

    2015-08-01

    A stable and efficient phosphorus-free, low Pd-loading heterogeneous nanocatalyst comprising palladium and a multi-walled carbon nanotube was prepared and characterized by various techniques such as SEM, TEM, AFM, FT-IR, and Raman spectrometry, N2 adsorption isotherm and thermogravimetric analysis. This catalyst was used for the deprotection of phenol ethers. The catalyst selectivity for deprotection of between propargyl, allyl, and benzyl, as a protecting group, was studied. Also, the presence of different functional groups was studied to establish the scope and limitations of this method. The catalytic activity of recycled catalyst was evaluated. The results indicated that the catalyst is heterogeneous, stable, and very active under the established conditions, and it could be reused up to five times without any significant leaching. In addition, according to ICP analysis, low leaves of leaching of palladium from the catalyst was observed, which indicates that anthraquinone has an excellent ability to coordinate with palladium.

  12. Prenatal natural history of isolated fetal mild bilateral pyelectasis

    PubMed Central

    de Paula Pereira, Gustavo; Bunduki, Victor; Hase, Eliane Azeka; Francisco, Rossana Pulcineli Vieira; Zugaib, Marcelo

    2016-01-01

    OBJECTIVE: To analyze the prenatal outcomes in a cohort of fetuses with mild bilateral pyelectasis and determine whether performing serial ultrasounds is a good follow-up strategy. METHODS: A prospective longitudinal study was conducted on 62 fetuses with mild bilateral pyelectasis. Fetal mild bilateral pyelectasis was considered when the renal pelvis measured (in millimeters) ≥5.0 to 10.0, ≥7.0 to 10.0, and ≥10.0 to 15 at ≤23 weeks 6 days, 24 to 31 weeks 6 days, and ≥32 weeks, respectively, with no uretero-calyceal dilatation. Ultrasounds were performed every 3 weeks to assess whether the mild bilateral pyelectasis regressed, remained unchanged (Group 1) or progressed (Group 2). RESULTS: Group 1 consisted of 53 fetuses (85.4%), and progression was observed in 9 cases (Group 2, 14.6%). The initial renal pelvis diameter was significantly larger in fetuses with progression (p=0.028). Statistically significant differences in the renal pelvis diameter were also found at weeks 31 and 35 for both kidneys (p<0.05). The cases requiring intrauterine procedures or early delivery were not observed. CONCLUSION: Fetal mild bilateral pyelectasis with no calyceal dilatation is a benign condition that can be managed in the postnatal period. The initial renal pelvis diameter and the diameter in week 31 or 35 were valuable parameters for identifying cases that would eventually need specific postnatal procedures. PMID:27652832

  13. Prenatal natural history of isolated fetal mild bilateral pyelectasis

    PubMed Central

    de Paula Pereira, Gustavo; Bunduki, Victor; Hase, Eliane Azeka; Francisco, Rossana Pulcineli Vieira; Zugaib, Marcelo

    2016-01-01

    OBJECTIVE: To analyze the prenatal outcomes in a cohort of fetuses with mild bilateral pyelectasis and determine whether performing serial ultrasounds is a good follow-up strategy. METHODS: A prospective longitudinal study was conducted on 62 fetuses with mild bilateral pyelectasis. Fetal mild bilateral pyelectasis was considered when the renal pelvis measured (in millimeters) ≥5.0 to 10.0, ≥7.0 to 10.0, and ≥10.0 to 15 at ≤23 weeks 6 days, 24 to 31 weeks 6 days, and ≥32 weeks, respectively, with no uretero-calyceal dilatation. Ultrasounds were performed every 3 weeks to assess whether the mild bilateral pyelectasis regressed, remained unchanged (Group 1) or progressed (Group 2). RESULTS: Group 1 consisted of 53 fetuses (85.4%), and progression was observed in 9 cases (Group 2, 14.6%). The initial renal pelvis diameter was significantly larger in fetuses with progression (p=0.028). Statistically significant differences in the renal pelvis diameter were also found at weeks 31 and 35 for both kidneys (p<0.05). The cases requiring intrauterine procedures or early delivery were not observed. CONCLUSION: Fetal mild bilateral pyelectasis with no calyceal dilatation is a benign condition that can be managed in the postnatal period. The initial renal pelvis diameter and the diameter in week 31 or 35 were valuable parameters for identifying cases that would eventually need specific postnatal procedures.

  14. Synchrotron emissivity from mildly relativistic particles

    NASA Technical Reports Server (NTRS)

    Petrosian, V.

    1981-01-01

    Approximate analytic expressions are presented for evaluation of the frequency and angular dependence of synchrotron emissivity from mildly relativistic particles with arbitrary energy spectrum and pitch angle distribution in a given magnetic field. Results agree with previous expressions for a nonrelativistic Maxwellian particle distribution, and when extrapolated to nonrelativistic and extreme relativistic regimes, they also agree with the previous expressions obtained under those limiting conditions. The results from the analytic expression are compared with results from detailed numerical evaluations. Excellent agreement is found not only at frequencies large compared to the gyro-frequency but also at lower frequencies, in fact, all the way down to the gyro-frequency, where the analytic approximations are expected to be less accurate.

  15. Functional Hubs in Mild Cognitive Impairment

    NASA Astrophysics Data System (ADS)

    Navas, Adrián; Papo, David; Boccaletti, Stefano; Del-Pozo, F.; Bajo, Ricardo; Maestú, Fernando; Martínez, J. H.; Gil, Pablo; Sendiña-Nadal, Irene; Buldú, Javier M.

    We investigate how hubs of functional brain networks are modified as a result of mild cognitive impairment (MCI), a condition causing a slight but noticeable decline in cognitive abilities, which sometimes precedes the onset of Alzheimer's disease. We used magnetoencephalography (MEG) to investigate the functional brain networks of a group of patients suffering from MCI and a control group of healthy subjects, during the execution of a short-term memory task. Couplings between brain sites were evaluated using synchronization likelihood, from which a network of functional interdependencies was constructed and the centrality, i.e. importance, of their nodes was quantified. The results showed that, with respect to healthy controls, MCI patients were associated with decreases and increases in hub centrality respectively in occipital and central scalp regions, supporting the hypothesis that MCI modifies functional brain network topology, leading to more random structures.

  16. Procedures for Increasing Sustained Attention in Adults with Mild Intellectual Disabilities

    ERIC Educational Resources Information Center

    Doughty, Adam H.; Williams, Dean C.

    2013-01-01

    This research compared the effects of several factors on sustained attention in four participants with mild or mild-to-moderate intellectual disabilities. In each session, each participant received an extended number of conditional discriminations that required a differential response to infrequently occurring target stimuli. We assessed sustained…

  17. Use of a Mild Gain Amplifier with Preschoolers with Language Delay.

    ERIC Educational Resources Information Center

    Flexer, Carol; Hallie, Savage

    1993-01-01

    This study examined effects on test-taking performance of enhancing the examiner's speech by means of an inexpensive mild gain hard-wired assistive listening device. Subjects were 11 preschoolers with mild expressive language delays. Results revealed a significant reduction in test-taking time in the amplified condition. (Author/DB)

  18. Simulation of mildly unsaturated flow

    NASA Astrophysics Data System (ADS)

    Letha, J.; Elango, K.

    1994-02-01

    In the study of unsaturated flow in the soil profile, the soil characteristic functions, one relating the pressure head to water saturation and the other relating the permeability to water saturation, are usually established with data covering a wide range. The application of these functions to situations with a mildly unsaturated range, such as encountered in a wet irrigation setting in a coarse soil, has been investigated. Certain shortcomings in using these soil characteristic functions directly have been identified, and modifications to the procedure of determining the characteristic functions have been proposed and tested. The improvements have been quantified in terms of the goodness of fit to published field measurements on the soil characteristics and also in terms of simulation results for an idealized test situation corresponding to irrigation practice in a relatively coarse soil. The special features of the C language have been utilized in developing a computer program for finite element modelling of the nonlinear Richards' equation describing unsaturated subsurface water flow. A weighted least-squares procedure improves the fit of the Brooks and Corey characteristic functions for pressure head vs. degree of saturation. A numerical integration procedure improves the fit of the Van Genuchten characteristic functions for permeability vs. degree of saturation. The present study indicates that even for sandy soil, the conventional Van Genuchten and Brooks and Corey soil characteristic functions need to be modified to yield acceptable results for the mildly unsaturated regime.

  19. Mild conditions for Pd-catalyzed carboamination of N-protected hex-4-enylamines and 1-, 3-, and 4-substituted pent-4-enylamines. Scope, limitations, and mechanism of pyrrolidine formation.

    PubMed

    Bertrand, Myra Beaudoin; Neukom, Joshua D; Wolfe, John P

    2008-11-21

    The use of the weak base Cs2CO3 in Pd-catalyzed carboamination reactions of N-protected gamma-aminoalkenes with aryl bromides leads to greatly increased tolerance of functional groups and alkene substitution. Substrates derived from (E)- or (Z)-hex-4-enylamines are stereospecifically converted to 2,1'-disubstituted pyrrolidine products that result from suprafacial addition of the nitrogen atom and the aryl group across the alkene. Transformations of 4-substituted pent-4-enylamine derivatives proceed in high yield to afford 2,2-disubstituted products, and cis-2,5- or trans-2,3-disubstituted pyrrolidines are generated in good yield with excellent diastereoselectivity from N-protected pent-4-enylamines bearing substituents at C1 or C3. The reactions tolerate a broad array of functional groups, including esters, nitro groups, and enolizable ketones. The scope and limitations of these transformations are described in detail, along with models that account for the observed product stereochemistry. In addition, deuterium labeling experiments, which indicate these reactions proceed via syn-aminopalladation of intermediate palladium(aryl)(amido)complexes regardless of degree of alkene substitution or reaction conditions, are also discussed. PMID:18942792

  20. A rechargeable Na-Zn hybrid aqueous battery fabricated with nickel hexacyanoferrate and nanostructured zinc

    NASA Astrophysics Data System (ADS)

    Lu, Ke; Song, Bin; Zhang, Jintao; Ma, Houyi

    2016-07-01

    Rechargeable aqueous batteries are very attractive as a promising alternative energy storage system, although their reversible capacity is typically limited. A new rechargeable Na-Zn hybrid aqueous battery with nickel hexacyanoferrate (NiHCF) cathode and the nanostructured zinc anode is fabricated. The rational combination of two materials with mild aqueous electrolyte renders the devices with an average operating voltage close to 1.5 V, higher specific capacity of 76.2 mAh g-1, and a good cycling stability with 81% capacity retention for 1000 cycles. These remarkable features can provide guidance for the development of rechargeable batteries from the naturally abundant electrode materials with neutral aqueous electrolytes.

  1. Capacitive behaviour of MnF2 and CoF2 submicro/nanoparticles synthesized via a mild ionic liquid-assisted route

    NASA Astrophysics Data System (ADS)

    Ma, Ruguang; Zhou, Yao; Yao, Lin; Liu, Guanghui; Zhou, Zhenzhen; Lee, Jong-Min; Wang, Jiacheng; Liu, Qian

    2016-01-01

    Submicro-/nano-sized MnF2 rods and hierarchical CoF2 cuboids are respectively synthesized via a facile precipitation method assisted by ionic liquid under a mild condition. The as-prepared MF2 (M = Mn, Co) submicro/nanoparticles exhibit impressive specific capacitance in 1.0 M KOH aqueous solution, especially at relatively high current densities, e.g. 91.2, 68.7 and 56.4 F g-1 for MnF2, and 81.7, 70.6 and 63.0 F g-1 for CoF2 at 5, 8 and 10 A g-1, respectively. The mechanism of striking capacitance of MF2 is clarified on the basis of analysing the cycled electrodes by different characterization techniques. Such remarkable capacitance is ascribed to the redox reactions between MF2 and MOOH in aqueous alkaline electrolytes, which can not be obtained in aqueous neutral electrolytes. This study for the first time provides direct evidences on the pseudocapacitance mechanism of MF2 in alkaline electrolytes and paves the way of application of transition metal fluorides as electrodes in supercapacitors.

  2. Multimorbidity and Risk of Mild Cognitive Impairment.

    PubMed Central

    Vassilaki, Maria; Aakre, Jeremiah A.; Cha, Ruth H.; Kremers, Walter K.; St. Sauver, Jennifer L.; Mielke, Michelle M.; Geda, Yonas E.; Machulda, Mary M.; Knopman, David S.; Petersen, Ronald C.; Roberts, Rosebud O

    2015-01-01

    OBJECTIVES To determine the association of multiple chronic conditions with risk of incident mild cognitive impairment (MCI)/dementia. DESIGN Prospective cohort study SETTING Olmsted County, Minnesota. PARTICIPANTS Cognitively normal individuals (N=2,176) enrolled in the Mayo Clinic Study of Aging (MCSA). MEASUREMENTS Participants were randomly selected from the community and evaluated by a study coordinator, a physician, and underwent neuropsychometric testing at baseline and at 15-month intervals to assess diagnoses of MCI and dementia. We electronically captured information on International Classification of Diseases, ninth revision (ICD-9) codes for chronic conditions in the five years prior to enrollment using the Rochester Epidemiology Project medical records linkage system. We defined multimorbidity as having two or more chronic conditions and examined the association of multimorbidity with MCI/dementia using Cox proportional hazards models. RESULTS Among 2,176 cognitively normal participants (mean [±SD] age 78.5 [±5.2] years; 50.6% men), 1,884 (86.6%) had multimorbidity. The risk of MCI/dementia was elevated in persons with multimorbidity (hazard ratio [HR]: 1.38; 95% confidence interval [CI], 1.05–1.82). The HR was stronger in persons with ≥4 conditions (HR: 1.61; 95%CI, 1.21–2.13) compared to persons with only 0 or 1 conditions, and for men (HR: 1.53, 95% CI, 1.01– 2.31) than for women (HR: 1.20, 95% CI, 0.83– 1.74). CONCLUSION In older adults, having multiple chronic conditions is associated with an increased risk of MCI/dementia. This is consistent with the hypothesis that multiple etiologies may contribute to MCI and late-life dementia. Preventing chronic diseases may be beneficial in delaying or preventing MCI or dementia. PMID:26311270

  3. Direct transformation of xylan-type hemicelluloses to furfural via SnCl₄ catalysts in aqueous and biphasic systems.

    PubMed

    Wang, Wenju; Ren, Junli; Li, Huiling; Deng, Aojie; Sun, Runcang

    2015-05-01

    Direct catalytic transformation of xylan-type hemicelluloses to furfural in the aqueous system and the biphasic system were comparatively investigated under mild conditions. Screening of several promising chlorides for conversion of beech xylan in the aqueous system revealed the Lewis acid SnCl4 was the most effective catalyst. Comparing to the single aqueous system, the bio-based 2-methyltetrahydrofuran (2-MTHF)/H2O biphasic system was more conducive to the synthesis of furfural, in which the highest furfural yield of 78.1% was achieved by using SnCl4 as catalysts under the optimized reaction conditions (150°C, 120 min). Additionally, the influences of xylan-type hemicelluloses with different chemical and structural features from beech, corncob and bagasse on the furfural production were studied. It was found that furfural yield to some extent was determined by the xylose content in hemicelluloses and also had relationships with the molecular weight of hemicelluloses and the degree of crystallization.

  4. Direct transformation of xylan-type hemicelluloses to furfural via SnCl₄ catalysts in aqueous and biphasic systems.

    PubMed

    Wang, Wenju; Ren, Junli; Li, Huiling; Deng, Aojie; Sun, Runcang

    2015-05-01

    Direct catalytic transformation of xylan-type hemicelluloses to furfural in the aqueous system and the biphasic system were comparatively investigated under mild conditions. Screening of several promising chlorides for conversion of beech xylan in the aqueous system revealed the Lewis acid SnCl4 was the most effective catalyst. Comparing to the single aqueous system, the bio-based 2-methyltetrahydrofuran (2-MTHF)/H2O biphasic system was more conducive to the synthesis of furfural, in which the highest furfural yield of 78.1% was achieved by using SnCl4 as catalysts under the optimized reaction conditions (150°C, 120 min). Additionally, the influences of xylan-type hemicelluloses with different chemical and structural features from beech, corncob and bagasse on the furfural production were studied. It was found that furfural yield to some extent was determined by the xylose content in hemicelluloses and also had relationships with the molecular weight of hemicelluloses and the degree of crystallization. PMID:25742750

  5. Mild serotonin syndrome: A report of 12 cases

    PubMed Central

    Prakash, Sanjay; Patel, Varsha; Kakked, Siddharth; Patel, Indravadan; Yadav, Rahul

    2015-01-01

    Serotonin syndrome (SS) is an under diagnosed and under reported condition. Mild SS is easily overlooked by physicians. Every patient with mild SS is a potential candidate for developing life-threatening severe SS because of inadvertent overdose or the addition of the second serotonergic drug. Herein, we describe 12 patients with mild SS observed over 12 months in neurology outpatient clinic. It is a retrospective chart review of 12 consecutive patients who had hyperreflexia with tremor (defined as mild SS Hunter's criteria) and had received serotonergic agents in the past 5 weeks. Only four patients (33%) reported tremor as a presenting or main feature. The presenting features in another eight patients were: Dizziness, generalized body pain, headache, and seizure. Five patients responded to the removal of the offending agents and got a complete response in 2-7 days. There were no or minimal responses in another seven patients to the removal of the serotonergic drugs. Cyproheptadine was started in these patients, at the dose of 8 mg three times daily. Response started within 1-3 days of initiation of the drug and the complete responses were noted in 5-14 days. There were no side effects from cyproheptadine in any patient. We suggest that any patient on serotonergic drug developing new symptoms should be examined for the presence of tremor, hypertonia, hyperreflexia, and clonus to look for mild SS. In addition, every patient on any serotonergic drug should be examined for the presence of mild SS before escalating the dose or before adding a new one. PMID:26019424

  6. Evaluation of aqueous-foam surfactants for geothermal drilling fluids

    SciTech Connect

    Rand, P.B.; Montoya, O.J.

    1983-07-01

    Aqueous foams are potentially useful drilling and cleanout fluids for geothermal applications. Successful use of foams requires surfactants (foaming agents) that can survive in the high-temperature geothermal environment. In this study, solutions of aqueous-foam-forming surfactants have been exposed to 260/sup 0/C (500/sup 0/F) and 310/sup 0/C (590/sup 0/F) in various chemical environments to determine if they can survive and make foams after exposure. Comparison of foams before and after exposure and the change in solution pH were used to evaluate their performance. Controlled liquid-volume-fraction foams, made in a packed-bed foam generator, were used for all tests. These tests have shown that many commercially available surfactants can survive short high-temperature cycles in mild acids, mild bases, and salt solutions as evidenced by their ability to make foams after exposure to high temperatures.

  7. A mild and facile synthesis of aryl and alkenyl sulfides via copper-catalyzed deborylthiolation of organoborons with thiosulfonates.

    PubMed

    Yoshida, Suguru; Sugimura, Yasuyuki; Hazama, Yuki; Nishiyama, Yoshitake; Yano, Takahisa; Shimizu, Shigeomi; Hosoya, Takamitsu

    2015-12-01

    An efficient deborylthiolation of aryl- and alkenylborons with thiosulfonates has been achieved under mild conditions using a copper catalyst. All steps of the experimental process were free from unpleasant odors. The mild reaction conditions as well as ready availability of boron compounds and thiosulfonates enabled easy access to an array of sulfides, including those bearing sensitive functional groups. PMID:26447905

  8. Evaluation of mild skin cleansers.

    PubMed

    Wortzman, M S

    1991-01-01

    Each person makes the decision of how best to care for his or her own skin. Among the prime concerns, especially for facial skin, is the type of dirt, debris, or make-up to be removed. In most cases, all products do an adequate job in the removal of dirt; if not, the washing techniques can be modified to accomplish the task at hand. What cannot be controlled are the adverse side effects inherent in the use of that product. These adverse properties include damages to the barrier function of the skin; increased susceptibility to environmental sources of irritation and sensitization; frank irritation responses, such as erythema and edema; and reduction of the cosmetic qualities of the skin, such as degree of moisture and smoothness. Part of the problem is that most of these changes are subtle, occurring slowly over time. Often, the association of these problems with the use of a particular facial cleansing regimen is overlooked. The typical woman uses as many as 10 to 15 facial cosmetic and cleansing products each day, making the identification of a problem even more difficult. It is important to identify the risks associated with individual products and with product categories in general. Although the identification of a safe group of products to use for facial cleansing is desirable, the results of this investigation indicate that there are no simple answers. It has been assumed that because moisturizing cream formulations are routinely safe and mild in general use, a cleansing product in the same general form would share these attributes. We can see from the results in Table 2 and Figures 2, 3, 5, 7, and 9 that cleansing creams are not uniformly superior to cleansing bars in the key attributes that are used to evaluate mildness. In each evaluation there were individual cleansing creams that demonstrated statistically weaker performance than did cleansing bars in general. As a group, cleansing creams did well in the cosmetic categories of dryness and texture but

  9. Aqueous extract of the pericarp of Sapindus trifoliatus fruits: a novel 'green' catalyst for the aldimine synthesis.

    PubMed

    Pore, Santosh; Rashinkar, Gajanan; Mote, Kavita; Salunkhe, Rajeshri

    2010-07-01

    The catalytic efficiency in organic synthesis of the aqueous extract of the pericarp of Sapindus trifoliatus fruits was evaluated. The synthesis of a series of aldimines from aromatic aldehydes and amines was successfully catalyzed by the extract, whereas aromatic ketones and amines did not yield ketimines under comparable reaction conditions, indicating the chemoselective catalysis of the extract. The catalytic activity of the extract is due to saponins, which have a common structural skeleton containing a pentacyclic triterpenoid part substituted with different carbohydrate side chains. The mild conditions, high yields, and short reaction times not only make this protocol a valuable alternative to the conventional methods, but it also becomes significant under the roof of environmentally greener and safer processes.

  10. Continuous Aqueous Tritium Monitoring

    SciTech Connect

    Hofstetter, K.J.

    1995-03-29

    Continuous monitoring for tritium in the aqueous effluents of selected Savannah River Site (SRS) facilities is performed using a custom designed system that includes an automated water purification system and a flow-through radiation detection system optimized for tritium. Beads of plastic scintillators coupled with coincidence electronics provide adequate sensitivity (=25kBz/L) for tritium break-through detection int he aqueous discharge stream from these facilities. The tritium effluent water monitors (TEWMs) at SRS provide early warning (within 30 minutes) of an unanticipated release of tritium, supplement the routine sampling surveillances, and mitigate the impact of aqueous plant discharges of tritium releases to the environment.

  11. Sucrose diffusion in aqueous solution.

    PubMed

    Price, Hannah C; Mattsson, Johan; Murray, Benjamin J

    2016-07-28

    The diffusion of sugar in aqueous solution is important both in nature and in technological applications, yet measurements of diffusion coefficients at low water content are scarce. We report directly measured sucrose diffusion coefficients in aqueous solution. Our technique utilises a Raman isotope tracer method to monitor the diffusion of non-deuterated and deuterated sucrose across a boundary between the two aqueous solutions. At a water activity of 0.4 (equivalent to 90 wt% sucrose) at room temperature, the diffusion coefficient of sucrose was determined to be approximately four orders of magnitude smaller than that of water in the same material. Using literature viscosity data, we show that, although inappropriate for the prediction of water diffusion, the Stokes-Einstein equation works well for predicting sucrose diffusion under the conditions studied. As well as providing information of importance to the fundamental understanding of diffusion in binary solutions, these data have technological, pharmaceutical and medical implications, for example in cryopreservation. Moreover, in the atmosphere, slow organic diffusion may have important implications for aerosol growth, chemistry and evaporation, where processes may be limited by the inability of a molecule to diffuse between the bulk and the surface of a particle. PMID:27364512

  12. Sucrose diffusion in aqueous solution

    PubMed Central

    Murray, Benjamin J.

    2016-01-01

    The diffusion of sugar in aqueous solution is important both in nature and in technological applications, yet measurements of diffusion coefficients at low water content are scarce. We report directly measured sucrose diffusion coefficients in aqueous solution. Our technique utilises a Raman isotope tracer method to monitor the diffusion of non-deuterated and deuterated sucrose across a boundary between the two aqueous solutions. At a water activity of 0.4 (equivalent to 90 wt% sucrose) at room temperature, the diffusion coefficient of sucrose was determined to be approximately four orders of magnitude smaller than that of water in the same material. Using literature viscosity data, we show that, although inappropriate for the prediction of water diffusion, the Stokes–Einstein equation works well for predicting sucrose diffusion under the conditions studied. As well as providing information of importance to the fundamental understanding of diffusion in binary solutions, these data have technological, pharmaceutical and medical implications, for example in cryopreservation. Moreover, in the atmosphere, slow organic diffusion may have important implications for aerosol growth, chemistry and evaporation, where processes may be limited by the inability of a molecule to diffuse between the bulk and the surface of a particle. PMID:27364512

  13. Non syndromic gingival fibromatosis in a mild mental retardation child

    PubMed Central

    Duddu, Mahesh K.; Muppa, Radhika; Reddy, G. S. Prasad; Reddy, P. Veerendra Nath

    2012-01-01

    Gingival fibromatosis is a benign oral condition characterized by enlargement of gingival tissues. It usually develops as an isolated disorder but can be one of the features of a syndrome. This case report is of a 5-year-old male with severe gingival hyperplasia and mild mental retardation which was complicated by open bite, abnormal occlusion, open lip posture, and disabilities associated with mastication and speech. Full mouth gingivectomy in single sitting under general anesthesia was done with electrocautery. PMID:23230365

  14. Reflectance of aqueous solutions

    NASA Technical Reports Server (NTRS)

    Querry, M. R.

    1972-01-01

    The optical properties and optical constants of water and aqueous solutions were studied to develop an accurate tabulation of graphical representations of the optical constants through a broad spectrum. Manuscripts of articles are presented concerning extinction coefficients, relative specular reflectance, and temperature effect on the water spectrum. Graphs of absolute reflectance, phase shifts, index of refraction, and extinction coefficients for water, heavy water and aqueous solutions are included.

  15. Separation of products from mild coal gasification processes

    SciTech Connect

    Wallman, P.H.

    1991-09-11

    The primary mild coal gasification product mixture containing noncondensible gas, high-boiling hydrocarbon vapors and entrained fines is difficult to process into the desired pure products: gas, liquids, and dry solids. This challenge for mild coal gasification process development has been studied by surveying the technical literature for suitable separations processes and for similar issues in related processes. The choice for a first-stage solids separation step is standard cyclones, arranged in parallel trains for large-volume applications in order to take advantage of the higher separation efficiency of smaller cyclones. However, mild gasification pilot-plant data show entrainment of ultrafine particles for which standard cyclones have poor separation efficiency. A hot secondary solids separation step is needed for the ultrafine entrainment in order to protect the liquid product from excessive amounts of contaminating solids. The secondary solids separation step is similar to many high-temperature flue-gas applications with an important complicating condition: Mild gasifier vapors form coke on surfaces in contact with the vapors. Plugging of the filter medium by coke deposition is concluded to be the main product separation problem for mild gasification. Three approaches to solution of this problem are discussed in the order of preference: (1) a barrier filter medium made of a perforated foil that is easy to regenerate, (2) a high-efficiency cyclone coupled with recycle of a solids-containing tar fraction for coking/cracking in the gasifier, and (3) a granular moving bed filter with regeneration of the bed material. The condensation of oil vapors diluted by noncondensible gas is analyzed thermodynamically, and the conclusion is that existing commercial oil fractionator designs are adequate as long as the vapor stream does not contain excessive amounts of solids. 34 refs., 4 figs.

  16. [Definition and clinical characteristics of mild hypertension].

    PubMed

    Saruta, Takao

    2008-08-01

    Mild hypertension is defined as blood pressure level of 140-159 mmHg systolic and/or 90-99 mmHg diastolic. The patients with blood pressure level of mild hypertension occupy about 60% of total hypertensive patients in Japan, and most of them are free of subjective symptoms except elevated blood pressure. However, some of the patients with mild hypertension develop cardiovascular events, since thay have occasionally cardiovascular damages on this level of blood pressure and several risk factors of cardiovascular diseases such as diabetes mellitus and hyperlipidemia.

  17. [Mild brain injuries in emergency medicine].

    PubMed

    Liimatainen, Suvi; Niskakangas, Tero; Ohman, Juha

    2011-01-01

    Diagnostics and correct classification of mild brain injuries is challenging. Problems caused by insufficient documentation at the acute phase become more obvious in situations in which legal insurance issues are to be considered. A small proportion of patients with mild brain injury suffer from prolonged symptoms. Medical recording and classification of the brain injury at the initial phase should therefore be carried out in a structured manner. The review deals with the diagnostic problems of mild brain injuries and presents a treatment protocol for adult patients at the acute phase, aiming at avoiding prolonged problems.

  18. Behavior of cellulose and xylan in aqueous ammonia pretreatment.

    PubMed

    Xin, Donglin; Jia, Lili; Zhao, Chengjuan; Zhang, Junhua

    2014-12-01

    The effect of aqueous ammonia on the solubilization of cellulose and xylans was investigated by detecting the amounts of reducing sugars and monosaccharides in the treatment liquors. The degree of cellulose and xylan solubilization increased with the increase of treatment temperature. When the treatment temperature increased from 20 to 90 °C, the amounts of reducing sugars released from Avicel and cellulose fiber by 21 % ammonia at a solid to liquid ratio of 1:10 for 24 h increased from 1.0 and 0.9 to 4.4 and 2.7 mg/g dry matter (DM), respectively. The amounts of reducing sugars released from wheat straw, beechwood, and oat spelt xylans increased from 1.2-7.0 to 3.3-13.5 mg/g DM. Xylans appeared to be more susceptible than cellulose in aqueous ammonia treatment. Structure analysis of untreated and treated Avicel and cellulose fiber showed that aqueous ammonia increased the specific surface area and crystallinity index of cellulose. Most of the cellulose and xylan that were solubilized existed in the form of oligomers such as cello-oligosaccharides and xylo-oligosaccharides. Xylobiose and xylotriose were the main oligosaccharides released from oat spelt xylan by aqueous ammonia treatment as confirmed by electrospray ionization-mass spectrometry. The results here indicated that a slight amount of cellulose and xylans was solubilized and low amounts of cellulase inhibitors, oligomers, were found during mild aqueous ammonia pretreatment process. Therefore, from the economical perspectives, mild ammonia pretreatment would be favorable for aqueous ammonia pretreatment of lignocelluloses.

  19. 21 CFR 522.144 - Arsenamide sodium aqueous injection.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Arsenamide sodium aqueous injection. 522.144... § 522.144 Arsenamide sodium aqueous injection. (a) Chemical name. dithio diacetic acid, sodium salt. (b... sodium. (c) Sponsor. See No. 050604 in § 510.600(c) of this chapter. (d) Conditions of use. (1) For...

  20. 21 CFR 522.144 - Arsenamide sodium aqueous injection.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Arsenamide sodium aqueous injection. 522.144... § 522.144 Arsenamide sodium aqueous injection. (a) Chemical name. dithio diacetic acid, sodium salt. (b... sodium. (c) Sponsor. See No. 050604 in § 510.600(c) of this chapter. (d) Conditions of use. (1) For...

  1. Toxicity studies of mild gasification products

    SciTech Connect

    Ong, T.M.; Whong, W.Z.; Ma, J.; Zhong, B.Z.; Bryant, D.

    1992-01-01

    The objectives of this project are: (1) to perform mutagenicity studies with the Ames Salmonella/microsomal assay system on coal liquids produced by mild gasification from different coals and/or processing conditions, (2) to determine whether coal liquids which are mutagenic to bacteria are also genotoxic to mammalian cells, (3) to establish correlations between mutagenicity, aromaticity, and boiling point range of coal liquids, and (4) to identify the chemical classes which are likely to be responsible for the mutagenic activity of gasification products. Four of the seven samples tested so far failed to demonstrate any mutagenic activity under any conditions tested. Those samples were SHELL[number sign]830331, MG-122IBP-420[degree]F, MG-122 420--720[degree]F, and MG-122 720[degree]F+. Table 1 summarizes the results from all samples tested in DMSO and Tween 80. When solvated in DMSO, MG-119 and MG-120 composite materials displayed slight, but ultimately insignificant, genotoxic activity on TA98 and TA1OO in the presence of S9. When Tween 80 was used as the solvent, MG-119 and MG-120 displayed slight, but significant, geno-toxic activity on TA98 with S9 (Figure 4). CTC[number sign]11 in DMSO displayed significant genotoxic activity on both TA98 and TA1OO with and without S9. The activity was higher on TA98 than TA100, and higher with S9 than without, primarily indicating the presence of indirect-acting frameshift mutagen. The results of the testing on CTC[number sign]11 were similar for both solvents, DMSO and Tween 80 (Table 2).

  2. Toxicity studies of mild gasification products

    SciTech Connect

    Ong, T.M.; Whong, W.Z.; Ma, J.; Zhong, B.Z.; Bryant, D.

    1992-11-01

    The objectives of this project are: (1) to perform mutagenicity studies with the Ames Salmonella/microsomal assay system on coal liquids produced by mild gasification from different coals and/or processing conditions, (2) to determine whether coal liquids which are mutagenic to bacteria are also genotoxic to mammalian cells, (3) to establish correlations between mutagenicity, aromaticity, and boiling point range of coal liquids, and (4) to identify the chemical classes which are likely to be responsible for the mutagenic activity of gasification products. Four of the seven samples tested so far failed to demonstrate any mutagenic activity under any conditions tested. Those samples were SHELL{number_sign}830331, MG-122IBP-420{degree}F, MG-122 420--720{degree}F, and MG-122 720{degree}F+. Table 1 summarizes the results from all samples tested in DMSO and Tween 80. When solvated in DMSO, MG-119 and MG-120 composite materials displayed slight, but ultimately insignificant, genotoxic activity on TA98 and TA1OO in the presence of S9. When Tween 80 was used as the solvent, MG-119 and MG-120 displayed slight, but significant, geno-toxic activity on TA98 with S9 (Figure 4). CTC{number_sign}11 in DMSO displayed significant genotoxic activity on both TA98 and TA1OO with and without S9. The activity was higher on TA98 than TA100, and higher with S9 than without, primarily indicating the presence of indirect-acting frameshift mutagen. The results of the testing on CTC{number_sign}11 were similar for both solvents, DMSO and Tween 80 (Table 2).

  3. Alexander disease with mild dorsal brainstem atrophy and infantile spasms.

    PubMed

    Torisu, Hiroyuki; Yoshikawa, Yoko; Yamaguchi-Takada, Yui; Yano, Tamami; Sanefuji, Masafumi; Ishizaki, Yoshito; Sawaishi, Yukio; Hara, Toshiro

    2013-05-01

    We present the case of a Japanese male infant with Alexander disease who developed infantile spasms at 8 months of age. The patient had a cluster of partial seizures at 4 months of age. He presented with mild general hypotonia and developmental delay. Macrocephaly was not observed. Brain magnetic resonance imaging (MRI) findings fulfilled all MRI-based criteria for the diagnosis of Alexander disease and revealed mild atrophy of the dorsal pons and medulla oblongata with abnormal intensities. DNA analysis disclosed a novel heterozygous missense mutation (c.1154 C>T, p.S385F) in the glial fibrillary acidic protein gene. At 8 months of age, tonic spasms occurred, and electroencephalography (EEG) revealed hypsarrhythmia. Lamotrigine effectively controlled the infantile spasms and improved the abnormal EEG findings. Although most patients with infantile Alexander disease have epilepsy, infantile spasms are rare. This comorbid condition may be associated with the distribution of the brain lesions and the age at onset of Alexander disease.

  4. PHOTOREACTION OF VALEROPHENONE IN AQUEOUS SOLUTION

    EPA Science Inventory

    Kinetics and products of the photoreaction of the phenyl ketone valerophenone were investigated as a function of temperature, pH, and wavelength in aqueous solution. Under these conditions (<10-4M), the photoreactions are pseudo-first-order with respect to valerophenone concentra...

  5. Comparing Cognitive Profiles of Licensed Drivers with Mild Alzheimer's Disease and Mild Dementia with Lewy Bodies

    PubMed Central

    Gagnon, Sylvain

    2016-01-01

    Purpose. Alzheimer's disease (AD) and dementia with Lewy Bodies (DLB) constitute two of the most common forms of dementia in North America. Driving is a primary means of mobility among older adults and the risk of dementia increases with advanced age. The purpose of this paper is to describe the cognitive profile of licensed drivers with mild AD and mild DLB. Method. Licensed drivers with mild AD, mild DLB, and healthy controls completed neuropsychological tests measuring general cognition, attention, visuospatial/perception, language, and cognitive fluctuations. Results. The results showed differences between healthy controls and demented participants on almost all neuropsychological measures. Participants with early DLB were found to perform significantly worse on some measures of attention and visuospatial functioning in comparison with early AD. Discussion. Future research should examine the relationship between neuropsychological measures and driving outcomes among individuals with mild AD and mild DLB. PMID:27774333

  6. Rheology of aqueous foams

    NASA Astrophysics Data System (ADS)

    Dollet, Benjamin; Raufaste, Christophe

    2014-10-01

    Aqueous foams are suspensions of bubbles inside aqueous phases. Their multiphasic composition leads to a complex rheological behavior that is useful in numerous applications, from oil recovery to food/cosmetic processing. Their structure is very similar to the one of emulsions, so that both materials share common mechanical properties. In particular, the presence of surfactants at the gas-liquid interfaces leads to peculiar interfacial and dissipative properties. Foam rheology has been an active research topics and is already reported in several reviews, most of them covering rheometry measurements at the scale of the foam, coupled with interpretations at the local scale of bubbles or interfaces. In this review, we start following this approach, then we try to cover the multiscale features of aqueous foam flows, emphasizing regimes where intermediate length scales need to be taken into account or regimes fast enough regarding internal time scales so that the flow goes beyond the quasi-static limit. xml:lang="fr"

  7. Corrosion inhibitor for aqueous ammonia absorption system

    DOEpatents

    Phillips, B.A.; Whitlow, E.P.

    1998-09-22

    A method is described for inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425 F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25 C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425 F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer. 5 figs.

  8. Corrosion inhibitor for aqueous ammonia absorption system

    DOEpatents

    Phillips, Benjamin A.; Whitlow, Eugene P.

    1998-09-22

    A method of inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425.degree. F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25.degree. C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425.degree. F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer.

  9. Carbon dioxide solubility in aqueous solutions of sodium chloride at geological conditions: Experimental results at 323.15, 373.15, and 423.15 K and 150 bar and modeling up to 573.15 K and 2000 bar

    NASA Astrophysics Data System (ADS)

    Zhao, Haining; Fedkin, Mark V.; Dilmore, Robert M.; Lvov, Serguei N.

    2015-01-01

    A new experimental system was designed to measure the solubility of CO2 at pressures and temperatures (150 bar, 323.15-423.15 K) relevant to geologic CO2 sequestration. At 150 bar, new CO2 solubility data in the aqueous phase were obtained at 323.15, 373.15, and 423.15 K from 0 to 6 mol kg-1 NaCl(aq) for the CO2-NaCl-H2O system. A γ - φ (activity coefficient - fugacity coefficient) type thermodynamic model is presented for the calculation of both the solubility of CO2 in the aqueous phase and the solubility of H2O in the CO2-rich phase for the CO2-NaCl-H2O system. Validation of the model calculations against literature data and other models (MZLL2013, AD2010, SP2010, DS2006, and OLI) show that the proposed model is capable of predicting the solubility of CO2 in the aqueous phase for the CO2-H2O and CO2-NaCl-H2O systems with a high degree of accuracy (AAD <3.9%) at temperatures from 273.15 to 573.15 K and pressures up to 2000 bar. A comparison of modeling results with experimental values revealed a pressure-bounded "transition zone" in which the CO2 solubility decreases to a minimum then increases as the temperature increases. CO2 solubility is not a monotonic function of temperature in the transition zone but outside of that transition zone, the CO2 solubility is decrease or increase monotonically in response to increased temperature. A link of web-based CO2 solubility computational tool can be provided by sending a message to Haining Zhao at hzz5047@gmail.com.

  10. Mild Traumatic Brain Injury in Translation

    PubMed Central

    Robertson, Claudia S.

    2013-01-01

    Abstract This Introduction to a Special Issue on Mild Traumatic Brain Injury (mTBI) highlights the methodological challenges in outcome studies and clinical trials involving patients who sustain mTBI. Recent advances in brain imaging and portable, computerized cognitive tasks have contributed to protocols that are sensitive to the effects of mTBI and efficient in time for completion. Investigation of civilian mTBI has been extended to single and repeated injuries in athletes and blast-related mTBI in service members and veterans. Despite differences in mechanism of injury, there is evidence for similar effects of acceleration-deceleration and blast mechanisms of mTBI on cognition. Investigation of repetitive mTBI suggests that the effects may be cumulative and that repeated mTBI and repeated subconcussive head trauma may lead to neurodegenerative conditions. Although animal models of mTBI using cortical impact and fluid percussion injury in rodents have been able to reproduce some of the cognitive deficits frequently exhibited by patients after mTBI, modeling post-concussion symptoms is difficult. Recent use of closed head and blast injury animal models may more closely approximate clinical mTBI. Translation of interventions that are developed in animal models to patients with mTBI is a priority for the research agenda. This Special Issue on mTBI integrates basic neuroscience studies using animal models with studies of human mTBI, including the cognitive sequelae, persisting symptoms, brain imaging, and host factors that facilitate recovery. PMID:23046349

  11. Leaf Responses to Mild Drought Stress in Natural Variants of Arabidopsis1[OPEN

    PubMed Central

    Clauw, Pieter; Coppens, Frederik; De Beuf, Kristof; Dhondt, Stijn; Van Daele, Twiggy; Maleux, Katrien; Storme, Veronique; Clement, Lieven; Gonzalez, Nathalie; Inzé, Dirk

    2015-01-01

    Although the response of plants exposed to severe drought stress has been studied extensively, little is known about how plants adapt their growth under mild drought stress conditions. Here, we analyzed the leaf and rosette growth response of six Arabidopsis (Arabidopsis thaliana) accessions originating from different geographic regions when exposed to mild drought stress. The automated phenotyping platform WIWAM was used to impose stress early during leaf development, when the third leaf emerges from the shoot apical meristem. Analysis of growth-related phenotypes showed differences in leaf development between the accessions. In all six accessions, mild drought stress reduced both leaf pavement cell area and number without affecting the stomatal index. Genome-wide transcriptome analysis (using RNA sequencing) of early developing leaf tissue identified 354 genes differentially expressed under mild drought stress in the six accessions. Our results indicate the existence of a robust response over different genetic backgrounds to mild drought stress in developing leaves. The processes involved in the overall mild drought stress response comprised abscisic acid signaling, proline metabolism, and cell wall adjustments. In addition to these known severe drought-related responses, 87 genes were found to be specific for the response of young developing leaves to mild drought stress. PMID:25604532

  12. Continuous aqueous tritium monitor

    DOEpatents

    McManus, Gary J.; Weesner, Forrest J.

    1989-05-30

    An apparatus for a selective on-line determination of aqueous tritium concentration is disclosed. A moist air stream of the liquid solution being analyzed is passed through a permeation dryer where the tritium and moisture and selectively removed to a purge air stream. The purge air stream is then analyzed for tritium concentration, humidity, and temperature, which allows computation of liquid tritium concentration.

  13. The extent of aqueous alteration in C-class asteroids, and the survival of presolar isotopic signatures in chondrites

    NASA Astrophysics Data System (ADS)

    Trigo-Rodriguez, J. M.

    2011-05-01

    Several sample return missions are being planned by different space agencies for in situ sampling of undifferentiated bodies. Such missions wish to bring back to Earth pristine samples from C-class asteroids and comets to obtain clues on solar system formation conditions. A careful selection of targeted areas is required as many C-class asteroids and periodic comets have been subjected to collisional and space weathering processing since their formation. Their surfaces have been reworked by impacts as pointed out by the brecciated nature of many chondrites arrived to Earth, exhibiting different levels of thermal and aqueous alteration. It is not surprising that pristine chondrites can be considered quite rare in meteorite collections because they were naturally sampled in collisions, but several groups of carbonaceous chondrites contain a few members with promising unaltered properties. The CI and CM groups suffered extensive aqueous alteration [1], but for the most part escaped thermal metamorphism (only a few CMs evidence heating temperature over several hundred K). Both chondrite groups are water-rich, containing secondary minerals as consequence of the pervasive alteration of their primary mineral phases [2]. CO, CV, and CR chondrite groups suffered much less severe aqueous alteration, but some CRs are moderately aqueously altered. All five groups are good candidates to find unequilibrated materials between samples unaffected by aqueous alteration or metamorphism. The water was incorporated during accretion, and was released as consequence of shock after impact compaction, and/or by mild radiogenic heating. Primary minerals were transformed by water into secondary ones. Water soaking the bodies participated in chemical homogenization of the different components [1]. Hydrothermal alteration and collisional metamorphism changed the abundances of isotopically distinguishable presolar silicates [3]. Additional instruments in the landers to identify aqueous

  14. Atomistic insights into aqueous corrosion of copper.

    SciTech Connect

    Jeon, B.; Sankaranarayanan, S. K. R. S.; van Duin, A. C. T.; Ramanathan, S.

    2011-06-21

    Corrosion is a fundamental problem in electrochemistry and represents a mode of failure of technologically important materials. Understanding the basic mechanism of aqueous corrosion of metals such as Cu in presence of halide ions is hence essential. Using molecular dynamics simulations incorporating reactive force-field (ReaxFF), the interaction of copper substrates and chlorine under aqueous conditions has been investigated. These simulations incorporate effects of proton transfer in the aqueous media and are suitable for modeling the bond formation and bond breakage phenomenon that is associated with complex aqueous corrosion phenomena. Systematic investigation of the corrosion process has been carried out by simulating different chlorine concentration and solution states. The structural and morphological differences associated with metal dissolution in the presence of chloride ions are evaluated using dynamical correlation functions. The simulated atomic trajectories are used to analyze the charged states, molecular structure and ion density distribution which are utilized to understand the atomic scale mechanism of corrosion of copper substrates under aqueous conditions. Increased concentration of chlorine and higher ambient temperature were found to expedite the corrosion of copper. In order to study the effect of solution states on the corrosion resistance of Cu, partial fractions of proton or hydroxide in water were configured, and higher corrosion rate at partial fraction hydroxide environment was observed. When the Cl{sup -} concentration is low, oxygen or hydroxide ion adsorption onto Cu surface has been confirmed in partial fraction hydroxide environment. Our study provides new atomic scale insights into the early stages of aqueous corrosion of metals such as copper.

  15. Do we over treat mild hypertension?

    PubMed

    Zanchetti, Alberto

    2015-06-01

    The important question whether 'mild' hypertension should or should not be treated by drugs is difficult to answer, because the only randomized controlled trials (RCTs) investigating this question were conducted when the definition of 'mild' hypertension was based on diastolic blood pressure only, whereas the present definition of grade 1 hypertension includes both systolic and diastolic values (SBP/DBP), and the concept of 'mild' hypertension also includes that of low-moderate cardiovascular risk (< 5% cardiovascular death rate in 5 years). Due to the lack of evidence from specific RCTs, guidelines recommend drug treatment of mild hypertension only on the basis of expert opinion. However, recent meta-analyses have provided some support to drug treatment intervention in low-moderate risk grade 1 hypertensives and have shown that, when treatment is deferred until organ damage or cardiovascular disease occur, absolute residual risk (events occurring despite treatment) markedly increases. Although evidence favoring therapeutic intervention in mild hypertension is nowadays stronger than expert opinion, meta-analyses are not substitutes for specific RCTs, and the wide BP spans defining grade 1 hypertension as well as the span defining low-moderate risk leave a wide space for individualized or personalized decisions.

  16. Iron oxide functionalized graphene nano-composite for dispersive solid phase extraction of chemical warfare agents from aqueous samples.

    PubMed

    Chinthakindi, Sridhar; Purohit, Ajay; Singh, Varoon; Tak, Vijay; Goud, D Raghavender; Dubey, D K; Pardasani, Deepak

    2015-05-15

    Present study deals with the preparation and evaluation of graphene based magnetic nano-composite for dispersive solid phase extraction of Chemical Weapons Convention (CWC) relevant chemicals from aqueous samples. Nano-composite, Fe3O4@SiO2-G was synthesized by covalently bonding silica coated Fe3O4 onto the graphene sheets. Nerve agents (NA), Sulfur mustard (SM) and their non-toxic environmental markers were the target analytes. Extraction parameters like amount of sorbent, extraction time and desorption conditions were optimized. Dispersion of 20 milligram of sorbent in 200mL of water sample for 20min. followed by methanol/chloroform extraction produced average to good recoveries (27-94%) of targeted analytes. Recoveries of real agents exhibited great dependency upon sample pH and ionic strength. Sarin produced maximum recovery under mild acidic conditions (56% at pH 5) while VX demanded alkaline media (83% at pH 9). Salts presence in the aqueous samples was found to be advantageous, raising the recoveries to as high as 94% for SM. Excellent limits of detection (LOD) for sulphur mustard and VX (0.11ngmL(-1) and 0.19ngmL(-1) respectively) proved the utility of the developed method for the off-site analysis of CWC relevant chemicals.

  17. Iron oxide functionalized graphene nano-composite for dispersive solid phase extraction of chemical warfare agents from aqueous samples.

    PubMed

    Chinthakindi, Sridhar; Purohit, Ajay; Singh, Varoon; Tak, Vijay; Goud, D Raghavender; Dubey, D K; Pardasani, Deepak

    2015-05-15

    Present study deals with the preparation and evaluation of graphene based magnetic nano-composite for dispersive solid phase extraction of Chemical Weapons Convention (CWC) relevant chemicals from aqueous samples. Nano-composite, Fe3O4@SiO2-G was synthesized by covalently bonding silica coated Fe3O4 onto the graphene sheets. Nerve agents (NA), Sulfur mustard (SM) and their non-toxic environmental markers were the target analytes. Extraction parameters like amount of sorbent, extraction time and desorption conditions were optimized. Dispersion of 20 milligram of sorbent in 200mL of water sample for 20min. followed by methanol/chloroform extraction produced average to good recoveries (27-94%) of targeted analytes. Recoveries of real agents exhibited great dependency upon sample pH and ionic strength. Sarin produced maximum recovery under mild acidic conditions (56% at pH 5) while VX demanded alkaline media (83% at pH 9). Salts presence in the aqueous samples was found to be advantageous, raising the recoveries to as high as 94% for SM. Excellent limits of detection (LOD) for sulphur mustard and VX (0.11ngmL(-1) and 0.19ngmL(-1) respectively) proved the utility of the developed method for the off-site analysis of CWC relevant chemicals. PMID:25828545

  18. Automatic Prosodic Analysis to Identify Mild Dementia.

    PubMed

    Gonzalez-Moreira, Eduardo; Torres-Boza, Diana; Kairuz, Héctor Arturo; Ferrer, Carlos; Garcia-Zamora, Marlene; Espinoza-Cuadros, Fernando; Hernandez-Gómez, Luis Alfonso

    2015-01-01

    This paper describes an exploratory technique to identify mild dementia by assessing the degree of speech deficits. A total of twenty participants were used for this experiment, ten patients with a diagnosis of mild dementia and ten participants like healthy control. The audio session for each subject was recorded following a methodology developed for the present study. Prosodic features in patients with mild dementia and healthy elderly controls were measured using automatic prosodic analysis on a reading task. A novel method was carried out to gather twelve prosodic features over speech samples. The best classification rate achieved was of 85% accuracy using four prosodic features. The results attained show that the proposed computational speech analysis offers a viable alternative for automatic identification of dementia features in elderly adults. PMID:26558287

  19. Automatic Prosodic Analysis to Identify Mild Dementia

    PubMed Central

    Gonzalez-Moreira, Eduardo; Torres-Boza, Diana; Kairuz, Héctor Arturo; Ferrer, Carlos; Garcia-Zamora, Marlene; Espinoza-Cuadros, Fernando; Hernandez-Gómez, Luis Alfonso

    2015-01-01

    This paper describes an exploratory technique to identify mild dementia by assessing the degree of speech deficits. A total of twenty participants were used for this experiment, ten patients with a diagnosis of mild dementia and ten participants like healthy control. The audio session for each subject was recorded following a methodology developed for the present study. Prosodic features in patients with mild dementia and healthy elderly controls were measured using automatic prosodic analysis on a reading task. A novel method was carried out to gather twelve prosodic features over speech samples. The best classification rate achieved was of 85% accuracy using four prosodic features. The results attained show that the proposed computational speech analysis offers a viable alternative for automatic identification of dementia features in elderly adults. PMID:26558287

  20. Neuropsychological function following mild exposure to pentaborane

    SciTech Connect

    Hart, R.P.; Silverman, J.J.; Garrettson, L.K.; Schulz, C.; Hamer, R.M.

    1984-01-01

    Neuropsychological tests and self-report personality inventories were administered to 14 workers and rescue squad personnel approximately 2 months following mild exposure to pentaborane, a highly toxic volatile liquid boron hydride. Performance decrements were evident on 5 of 11 neuropsychological tests, including Block Design and measures of sustained attention and recent memory. Neuropsychological deficits were not related to emotional changes reported on the Hopkins Symptom Checklist nor to the presence of CT scan abnormality. These results indicate mild residual brain dysfunction following pentaborane intoxication, including possible dysfunction in subcortical regions mediating memory processes and in cortical areas mediating visuo-spatial abilities.

  1. Mild bleeding disorders: review of 120 patients.

    PubMed

    Bolton-Maggs, P; Wilkinson, L S

    1984-01-01

    Of 120 patients presenting with mild bleeding disorders, 63 were found to have a definite coagulopathy. The commonest disorders were haemophilia, Christmas disease and von Willebrand's disease (vWd), the latter being predominant. Diagnosis led to prophylactic treatment prior to surgery in 18 patients with prevention of excessive haemorrhage. Three patients who had received blood products developed hepatitis. DDAVP (desamino-cys-1-8-D-arginine vasopressin) is the treatment of choice in suitable mildly affected patients with haemophilia A and vWd. Examination of blood group distribution suggests an excess of group O among patients with bleeding disorders, especially those with vWd.

  2. Regulatory aspects of mild cognitive impairment: toward a harmonized perspective

    PubMed Central

    Whitehouse, Peter J.

    2004-01-01

    The development of the concept of mild cognitive impairment (MCI) and its practical application have been intimately tied to attempts to produce therapeutic agents. Understanding the regulatory environment and determining the way in which it can be influenced are critical to the development of drugs and their eventual approval. In this article, we review some of the current challenges surrounding the concept of MCI relevant to drug development, summarize activities in various regions of the world, and conclude with some suggested next steps and an alternative framing for approving drugs for MCI and related conditions. PMID:22033834

  3. Continuous aqueous tritium monitor

    DOEpatents

    McManus, G.J.; Weesner, F.J.

    1987-10-19

    An apparatus for a selective on-line determination of aqueous tritium concentration is disclosed. A moist air stream of the liquid solution being analyzed is passed through a permeation dryer where the tritium and moisture are selectively removed to a purge air stream. The purge air stream is then analyzed for tritium concentration, humidity, and temperature, which allows computation of liquid tritium concentration. 2 figs.

  4. Aqueous Based Semiconductor Nanocrystals.

    PubMed

    Jing, Lihong; Kershaw, Stephen V; Li, Yilin; Huang, Xiaodan; Li, Yingying; Rogach, Andrey L; Gao, Mingyuan

    2016-09-28

    This review summarizes traditional and recent nonconventional, bioinspired, methods for the aqueous synthesis of colloidal semiconductor quantum dots (QDs). The basic chemistry concepts are critically emphasized at the very beginning as these are strongly correlated with the selection of ligands and the optimal formation of aqueous QDs and their more sophisticated structures. The synergies of biomimetic and biosynthetic methods that can combine biospecific reactivity with the robust and strong optical responses of QDs have also resulted in new approaches to the synthesis of the nanoparticles themselves. A related new avenue is the recent extension of QD synthesis to form nanoparticles endowed with chiral optical properties. The optical characteristics of QD materials and their advanced forms such as core/shell heterostructures, alloys, and doped QDs are discussed: from the design considerations of optical band gap tuning, the control and reduction of the impact of surface traps, the consideration of charge carrier processes that affect emission and energy and charge transfer, to the impact and influence of lattice strain. We also describe the considerable progress in some selected QD applications such as in bioimaging and theranostics. The review concludes with future strategies and identification of key challenges that still need to be resolved in reaching very attractive, scalable, yet versatile aqueous syntheses that may widen the scope of commercial applications for semiconductor nanocrystals. PMID:27586892

  5. Morphological and structural evolution of alpha-MnO{sub 2} nanorods synthesized via an aqueous route through MnO{sub 4}{sup -}/Mn{sup 2+} reaction

    SciTech Connect

    Fu Xiaobo; Feng Jiyun; Wang Huan; Ng, Ka Ming

    2010-04-15

    An aqueous route through MnO{sub 4}{sup -}/Mn{sup 2+} reaction under mild conditions was used to synthesize alpha-MnO{sub 2} nanorods. The morphological and structural evolution of alpha-MnO{sub 2} nanorods during their growth were tracked by Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and BET analysis. The crystallization of alpha-MnO{sub 2} nanorods was found to proceed through three steps: (1) Amorphous or poorly ordered nuclei formed first. (2) Then hollow nanoshperes consisting of gamma-MnO{sub 2} nanorods formed via the Ostwald ripening process. (3) The hollow nanospheres broke down and the gamma-MnO{sub 2} nanorods finally transformed into the alpha-MnO{sub 2} nanorods with increasing temperature or reaction time. The phase transformation from gamma-MnO{sub 2} to alpha-MnO{sub 2} nanorods was accomplished by a short-range rearrangement of MnO{sub 6} octahedra. In addition, the performance of the MnO{sub 2} materials as a catalyst was evaluated in the aerobic oxidation of benzyl alcohol, showing that their catalytic activities were mainly dependent on their BET surface areas. - Graphical abstract: alpha-MnO{sub 2} nanorods were synthesized via an aqueous route through MnO{sub 4}{sup -}/Mn{sup 2+} reaction under mild conditions.

  6. Adapalene. A review of its pharmacological properties and clinical potential in the management of mild to moderate acne.

    PubMed

    Brogden, R N; Goa, K E

    1997-03-01

    Adapalene, a naphthoic acid derivative with retinoid-like activity, is used for the topical treatment of mild to moderate acne vulgaris. It binds to retinoic acid receptors found predominantly in the terminal differentiation zone of epidermis and is more active than tretinoin in modulating cellular differentiation. Adapalene exhibits anti-inflammatory activity in various in vitro and in vivo models. To date, adapalene 0.1% gel and lotion formulations have been compared only with tretinoin 0.025% gel. In these comparisons, adapalene 0.1% aqueous gel was at least as effective as tretinoin and in some studies was significantly better at reducing the numbers of noninflammatory, inflammatory and total facial lesions in patients with mild to moderate acne. In such comparisons, the cutaneous tolerability of adapalene aqueous gel was generally better than that of tretinoin. On the basis of published data, adapalene aqueous 0.1% gel is an effective and generally better tolerated alternative to tretinoin 0.025% gel for the topical treatment of patients with mild to moderate acne.

  7. Social skills training with mildly retarded young adults.

    PubMed

    Meredith, R L; Saxon, S; Doleys, D M; Kyzer, B

    1980-10-01

    Described a social skills assessment and training model for use with mildly retarded young adults (N = 20). The assessment procedure examined social behavior in three types of social situations (e.g., conversational situation, cooperative task and assertive situation) with both male and female respondents. Group behavioral social skills training was compared with a no treatment control condition using various dependent measures collected in the in-vivo social situations. Group behavioral social skills training was more effective than the control condition in increasing positive social behavior, attention to the transaction, and degree of empathy. It was also more effective than a control condition in decreasing negative social skill behavior. A situation effect also was observed, which suggests a need for more focus on particular social skills and a need to address issues of generalization. A comprehensive social skills assessment and training model is discussed. PMID:7440726

  8. Halfway Houses for the Mildly Retarded.

    ERIC Educational Resources Information Center

    Gia, Gilbert P.

    Investigated were number and location of community residences or halfway houses (of fewer than 61 persons) for the mildly retarded and their programing practices. Form letters and questionnaires uncovered 68 programs meeting internal delimitations of the study. Programs were categorized for analysis purposes into California Programs, New Programs…

  9. Mildly Retarded Adults: Their Attitudes Toward Retardation

    ERIC Educational Resources Information Center

    Gan, Jennifer; And Others

    1977-01-01

    Responses to a 40-item questionnaire distributed to 50 mildly mentally retarded (MR) adults indicate that the majority possess accurate information about MR, hold realistic attitudes toward their own needs and abilities, and advocate community integration of the retarded. (Author/JG)

  10. Learning Strategies for Adolescents with Mild Disabilities

    ERIC Educational Resources Information Center

    Conderman, Greg; Koman, Kara; Schibelka, Mary; Higgin, Karen; Cooper, Cody; Butler, Jordyn

    2013-01-01

    Learning strategy instruction is an evidence-based practice for teaching adolescents with mild disabilities. However, researchers have not developed strategies for every content area or skill. Therefore, teachers need to be able develop strategies based on the needs of their students. This article reviews the process for developing and teaching…

  11. Water-Soluble Nonconjugated Polymer Nanoparticles with Strong Fluorescence Emission for Selective and Sensitive Detection of Nitro-Explosive Picric Acid in Aqueous Medium.

    PubMed

    Liu, Shi Gang; Luo, Dan; Li, Na; Zhang, Wei; Lei, Jing Lei; Li, Nian Bing; Luo, Hong Qun

    2016-08-24

    Water-soluble nonconjugated polymer nanoparticles (PNPs) with strong fluorescence emission were prepared from hyperbranched poly(ethylenimine) (PEI) and d-glucose via Schiff base reaction and self-assembly in aqueous phase. Preparation of the PEI-d-glucose (PEI-G) PNPs was facile (one-pot reaction) and environmentally friendly under mild conditions. Also, PEI-G PNPs showed a high fluorescence quantum yield in aqueous solution, and the fluorescence properties (such as concentration- and solvent-dependent fluorescence) and origin of intrinsic fluorescence were investigated and discussed. PEI-G PNPs were then used to develop a fluorescent probe for fast, selective, and sensitive detection of nitro-explosive picric acid (PA) in aqueous medium, because the fluorescence can be easily quenched by PA whereas other nitro-explosives and structurally similar compounds only caused negligible quenching. A wide linear range (0.05-70 μM) and a low detection limit (26 nM) were obtained. The fluorescence quenching mechanism was carefully explored, and it was due to a combined effect of electron transfer, resonance energy transfer, and inner filter effect between PA and PEI-G PNPs, which resulted in good selectivity and sensitivity for PA. Finally, the developed sensor was successfully applied to detection of PA in environmental water samples. PMID:27471907

  12. Inorganic nitrogen reduction and stability under simulated hydrothermal conditions.

    PubMed

    Brandes, Jay A; Hazen, Robert M; Yoder, Hatten S

    2008-12-01

    Availability of reduced nitrogen is considered a prerequisite for the genesis of life from prebiotic precursors. Most atmospheric and oceanic models for the Hadean Earth predict a mildly oxidizing environment that is conducive to the formation and stability of only oxidized forms of nitrogen. A possible environment where reduction of oxidized nitrogen to ammonium has been speculated to occur is aqueous hydrothermal systems. We examined a suite of transition metal oxides and sulfides for their ability to reduce nitrate and nitrite, as well as oxidize ammonia, under hot (300 degrees C) high-pressure (50-500 MPa) aqueous conditions. In general, iron sulfides exhibited the most rapid and complete conversion noted, followed by nickel and copper sulfides to a much lower degree. Of the oxides examined, only magnetite exhibited any ability to reduce NO(3)(-) or NO(2)(-). Ammonium was stable or exhibited small losses (<20%) in contact with all the mineral phases and conditions tested. The results support the idea that hydrothermal systems could have provided significant amounts of reduced nitrogen to their immediate environments. The enhanced availability of reduced nitrogen in hydrothermal systems also has important implications for prebiotic metabolic pathways where nitrogen availability is critical to the production of amino acids and other nitrogenous compounds. PMID:19191539

  13. Carboxymethylcellulose from recycled newspaper in aqueous medium.

    PubMed

    Unlü, Cüneyt H

    2013-08-14

    Recycled paper cellulose has some drawbacks, for example loss in mechanical strength, to use in paper industry alone. However, derivatives of cellulose can find applications in other industrial areas. Carboxymethylcellulose (CMC) is one of the most used cellulose derivatives and can be obtained by heterogeneous modification of cellulose. In general carboxymethylation of cellulose achieved in alkaline alcoholic dispersions. In this work modification of cellulose from recycled newspaper in aqueous alkaline solution was aimed. First cellulose was recovered from newspaper under oxidative alkaline conditions. Cellulose recovery was determined as 75-90% (w/w) of starting material. Carboxymethylation reactions were carried out to find optimum conditions for derivatization, changing concentrations of components and reaction temperature. Obtained CMC samples had a DS of 0.3-0.7% and 84-94% CMC content. As a result, carboxymethylation of cellulose from recycled newspaper was achieved in aqueous alkaline dispersion giving commercial grade CMC for industrial use.

  14. Supercritical waste oxidation of aqueous wastes

    NASA Technical Reports Server (NTRS)

    Modell, M.

    1986-01-01

    For aqueous wastes containing 1 to 20 wt% organics, supercritical water oxidation is less costly than controlled incineration or activated carbon treatment and far more efficient than wet oxidation. Above the critical temperature (374 C) and pressure (218 atm) of water, organic materials and gases are completely miscible with water. In supercritical water oxidation, organics, air and water are brought together in a mixture at 250 atm and temperatures above 400 C. Organic oxidation is initiated spontaneously at these conditions. The heat of combustion is released within the fluid and results in a rise in temperature 600 to 650 C. Under these conditions, organics are destroyed rapidly with efficiencies in excess of 99.999%. Heteroatoms are oxidized to acids, which can be precipitated out as salts by adding a base to the feed. Examples are given for process configurations to treat aqueous wastes with 10 and 2 wt% organics.

  15. Phosphate Sorption and Desorption on Pyrite in Primitive Aqueous Scenarios: Relevance of acidic → Alkaline Transitions

    NASA Astrophysics Data System (ADS)

    de Souza-Barros, Fernando; Braz-Levigard, Raphael; Ching-San, Yonder; Monte, Marisa M. B.; Bonapace, José A. P.; Montezano, Viviane; Vieyra, Adalberto

    2007-02-01

    Phosphate (P i) sorption assays onto pyrite in media simulating primeval aquatic scenarios affected by hydrothermal emissions, reveal that acidic conditions favour P i sorption whereas mild alkaline media as well as those simulating sulfur oxidation to SO2- 4 revert this capture process. Several mechanisms relevant to P i availability in prebiotic eras are implicated in the modulation of these processes. Those favouring sorption are: (a) hydrophobic coating of molecules, such as acetate that could be formed in the vicinity of hydrothermal vents; (b) water and Mg2+ bridging in the interface mineral-aqueous media; (c) surface charge neutralization by monovalent cations (Na+ and K+). The increase of both the medium pH and the SO2- 4 trapping by the mineral interface would provoke the release of sorbed P i due to charge polarization. Moreover it is shown that P i self-modulates its sorption, a mechanism that depends on the abundance of SO2- 4 in the interface. The relevance of the proposed mechanisms of P i capture, release and trapping arises from the need of abundant presence of this molecule for primitive phosphorylations, since similarly to contemporary aqueous media inorganic phosphate concentrations in primitive seas should have been low. It is proposed that the presence of sulphide minerals with high affinity to P i could have trapped this molecule in an efficient manner, allowing its concentration in specific niches. In these niches, the conditions studied in the present work would have been relevant for its availability in soluble form, specially in primitive insulated systems with pH gradients across the wall.

  16. Phosphate sorption and desorption on pyrite in primitive aqueous scenarios: relevance of acidic --> alkaline transitions.

    PubMed

    de Souza-Barros, Fernando; Braz-Levigard, Raphael; Ching-San, Yonder; Monte, Marisa M B; Bonapace, José A P; Montezano, Viviane; Vieyra, Adalberto

    2007-02-01

    Phosphate (P(i)) sorption assays onto pyrite in media simulating primeval aquatic scenarios affected by hydrothermal emissions, reveal that acidic conditions favour P(i) sorption whereas mild alkaline media--as well as those simulating sulfur oxidation to SO(2-) (4)--revert this capture process. Several mechanisms relevant to P(i) availability in prebiotic eras are implicated in the modulation of these processes. Those favouring sorption are: (a) hydrophobic coating of molecules, such as acetate that could be formed in the vicinity of hydrothermal vents; (b) water and Mg(2+) bridging in the interface mineral-aqueous media; (c) surface charge neutralization by monovalent cations (Na+ and K+). The increase of both the medium pH and the SO(2-) (4) trapping by the mineral interface would provoke the release of sorbed P(i) due to charge polarization. Moreover it is shown that P(i) self-modulates its sorption, a mechanism that depends on the abundance of SO(2-) (4) in the interface. The relevance of the proposed mechanisms of P(i) capture, release and trapping arises from the need of abundant presence of this molecule for primitive phosphorylations, since--similarly to contemporary aqueous media--inorganic phosphate concentrations in primitive seas should have been low. It is proposed that the presence of sulphide minerals with high affinity to P(i) could have trapped this molecule in an efficient manner, allowing its concentration in specific niches. In these niches, the conditions studied in the present work would have been relevant for its availability in soluble form, specially in primitive insulated systems with pH gradients across the wall.

  17. Aqueous Humor Dynamics: A Review

    PubMed Central

    Goel, Manik; Picciani, Renata G; Lee, Richard K; Bhattacharya, Sanjoy K

    2010-01-01

    Glaucoma is a family of optic neuropathies which cause irreversible but potentially preventable vision loss. Vision loss in most forms of glaucoma is related to elevated IOP with subsequent injury to the optic nerve. Secretion of aqueous humor and regulation of its outflow are physiologically important processes for maintaining IOP in the normal range. Thus, understanding the complex mechanisms that regulate aqueous humor circulation is essential for management of glaucoma. The two main structures related to aqueous humor dynamics are the ciliary body and the trabecular meshwork (TM). Three mechanisms are involved in aqueous humor formation: diffusion, ultrafiltration and active secretion. Active secretion is the major contributor to aqueous humor formation. The aqueous humor flow in humans follows a circadian rhythm, being higher in the morning than at night. The aqueous humor leaves the eye by passive flow via two pathways - the trabecular meshwork and the uveoscleral pathway. In humans, 75% of the resistance to aqueous humor outflow is localized within the TM with the juxtacanalicular portion of the TM being the main site of outflow resistance. Glycosaminoglycan deposition in the TM extracellular matrix (ECM) has been suggested to be responsible for increased outflow resistance at this specific site whereas others have suggested deposition of proteins, such as cochlin, obstruct the aqueous humor outflow through the TM. The uveoscleral outflow pathway is relatively independent of the intraocular pressure and the proportion of aqueous humor exiting the eye via the uveoscleral pathway decreases with age. PMID:21293732

  18. FIA titrations of phenothiazine derivatives in aqueous micellar and non-aqueous media.

    PubMed

    Nemcová, Irena; Nesmerák, Karel; Rychlovský, Petr; Koutníková, Jitka

    2005-02-15

    New methods of flow injection analysis (FIA) neutralization titrations of phenothiazine derivatives in aqueous micellar medium of a cationic surfactant using potentiometric and spectrophotometric detection were proposed; titrations with a mixing gradient chamber and high-speed titrations were compared. The FIA titration method in non-aqueous media based on an official method of determination (titration with perchloric acid in anhydrous acetic acid) was also developed. Under optimized reaction conditions and flow-through parameters, the calibration range and equations, the sensitivity, and the repeatability of all methods were found and discussed. All titrations were assayed for medicinal forms.

  19. Sorption of tetracycline antibiotics on hyper-crosslinked polystyrene from aqueous and aqueous-organic media

    NASA Astrophysics Data System (ADS)

    Udalova, A. Yu.; Dmitrienko, S. G.; Apyari, V. V.

    2015-06-01

    The sorption of tetracycline, oxytetracycline, chlortetracycline, and doxycycline on hyper-cross-linked polystyrene from aqueous and aqueous-organic solutions is studied under static and dynamic conditions in order to extend the range of the sorbents suitable for sorption isolation and the preconcentration of tetracycline antibiotics. Features of tetracycline sorption depending on the acidity of a solution and the nature and concentration of the compounds are explained. It is shown that hyper-crosslinked polystyrene can be used for the group sorption preconcentration of these compounds.

  20. A novel method of non-violent dissolution of sodium metal in a concentrated aqueous solution of Epsom salt

    NASA Astrophysics Data System (ADS)

    Lakshmanan, A. R.; Prasad, M. V. R.; Ponraju, D.; Krishnan, H.

    2004-10-01

    A new technique of non-violent and fast dissolution of sodium metal in a concentrated aqueous solution of Epsom salt (MgSO4.7H2O) at room temperature (RT) has been developed. The dissolution process is mildly exothermic but could be carried out even in a glass beaker in air under swift stirring condition. The reaction products consist of mixed salts of MgSO4 and Na2SO4 as well as Mg(OH)2 which are only mildly alkaline and hence are non-corrosive and non-hazardous unlike NaOH. A 50 mL solution having Epsom salt concentration of 2 M was found to give the optimal composition for disposal of 1 g of sodium. Supersaturated (>2.7 M), as well as dilute (<1.1 M) solutions, however, cause violent reactions and hence should be avoided. Repeated sodium dissolution in Epsom solution produced a solid waste of 4.7 g per g of sodium dissolved which is comparable with the waste (4 g) produced in 8 M NaOH solution. A 1.4 M Epsom solution sprayed with a high-pressure jet cleaner at RT in air easily removed the sodium blocked inside a metal pipe made of mild steel. The above jet also dissolved peacefully residual sodium collected on the metal tray after a sodium fire experiment. No sodium fire or explosion was observed during this campaign. The Epsom solution spray effectively neutralized the minor quantity of sodium aerosol produced during this campaign. This novel technique would hence be quite useful for draining sodium from fast breeder reactor components and bulk processing of sodium as well as for sodium fire fighting.

  1. Development of an advanced, continuous mild gasification process for the production of co-products

    SciTech Connect

    Wolfe, R.A.; Wright, R.E.; Im, C.J.; Henkelman, M.R.; O`Neal, G.W.

    1992-11-01

    The objective of this project is to develop a continuous mild gasification process to convert highly caking coals to coal liquids, char and coke for near term commercial application. Task 3, Bench-Scale Char Upgrading Study, has been underway since September 1989. In char upgrading studies, ``green`` uncured char briquettes have been prepared and calcined in 20-pound batches to evaluate the effects of char, binders, and heating conditions on final coke properties. A total of 150. formulations have been tested thus far in this work. Work on Task 4, Process Development Unit (PDU) Mild Gasification Study, has been in progress since February 1991, with the completion of a Continuous Mild Gasification Unit (CMGU) with a design rate of 1000 lb./hr. Since start-up of the CMGU, there have been 72 runs with a variety of operating conditions and coal types.

  2. Nova outbursts in the case of mild hibernation

    SciTech Connect

    Livio, M.; Shankar, A.; Truran, J.W.

    1988-02-01

    The necessary conditions for the production of strong thermonuclear runaways in the hibernation scenario are identified and explored. It is found that a reduction in the accretion rate by a factor of about 100, for a period longer than a few thousand years, is generally sufficient to ensure nova-type outbursts, even in the presence of rather high preoutburst accretion rates. Nova outbursts can be obtained under mild hibernation conditions on 1 solar mass white dwarfs as well as on very massive ones. A reduction in the accretion rate by a factor of 10 only is insufficient to produce a nova outburst, if the preoutburst accretion rate is as high as 10 to the -8th solar mass/yr. 28 references.

  3. Mild stimulation in in vitro fertilization.

    PubMed

    Macklon, N S; Fauser, B C J M

    2003-11-01

    Current approaches to ovarian stimulation for in vitro fertilization (IVF) are aimed at optimizing the number of oocytes retrieved in a treatment cycle. This approach is not without risks. Moreover, as the true costs of multiple pregnancy become clearer, the need to produce multiple embryos for transfer is increasingly questioned. Increasing knowledge of the physiological mechanisms involved in follicular development and dominance has led to new strategies in ovarian stimulation for IVF. The clinical availability of GnRH antagonists allows the normal cycle to be harnessed and manipulated by mild interventions to produce sufficient oocytes for successful IVF treatment. Recent evidence suggests that oocyte quality after mild stimulation may be superior to that after conventional stimulation regimens.

  4. The ENCOAL Mild Gasification Demonstration Project

    SciTech Connect

    Not Available

    1990-07-01

    The DOE plans to enter into a Cooperative Agreement with ENCOAL Corporation, a wholly owned subsidiary of Shell Mining Company, for the cost-shared design, construction and operation of a mild gasification facility based on Liquids-from-Coal (LFC) technology. The facility is planned to be located at the Triton Coal Company's Buckskin Mine near Gillette, Wyoming. The mild gasification process to be demonstrated will produce two new, low-sulfur fuel forms (a solid and a liquid) from subbituminous coal. The new fuel forms would be suitable for combustion in commercial, industrial, and utility boilers. This environmental assessment has been prepared by the DOE to comply with the requirements of the NEPA. Pollutant emissions, land use, water, and waste management are briefly discussed. 3 figs., 5 tabs.

  5. Mars aqueous chemistry experiment

    NASA Technical Reports Server (NTRS)

    Clark, Benton C.; Mason, Larry W.

    1994-01-01

    Mars Aqueous Chemistry Experiment (MACE) is designed to conduct a variety of measurements on regolith samples, encompassing mineral phase analyses, chemical interactions with H2O, and physical properties determinations. From these data, much can be learned or inferred regarding the past weathering environment, the contemporaneous soil micro-environments, and the general chemical and physical state of the Martian regolith. By analyzing both soil and duricrust samples, the nature of the latter may become more apparent. Sites may be characterized for comparative purposes and criteria could be set for selection of high priority materials on future sample return missions. The second year of the MACE project has shown significant progress in two major areas. MACE Instrument concept definition is a baseline design that has been generated for the complete MACE instrument, including definition of analysis modes, mass estimates and thermal model. The design includes multiple reagent reservoirs, 10 discrete analysis cells, sample manipulation capability, and thermal control. The MACE Measurement subsystems development progress is reported regarding measurement capabilities for aqueous ion sensing, evolved gas sensing, solution conductivity measurement, reagent addition (titration) capabilities, and optical sensing of suspended particles.

  6. Aqueous cleaning design presentation

    NASA Technical Reports Server (NTRS)

    Maltby, Peter F.

    1995-01-01

    The phase-out of CFC's and other ozone depleting chemicals has prompted industries to re-evaluate their present methods of cleaning. It has become necessary to find effective substitutes for their processes as well as to meet the new cleaning challenges of improved levels of cleanliness and to satisfy concerns about environmental impact of any alternative selected. One of the most popular alternatives being selected is aqueous cleaning. This method offers an alternative for removal of flux, grease/oil, buffing compound, particulates and other soils while minimizing environmental impact. What I will show are methods that can be employed in an aqueous cleaning system that will make it environmentally friendly, relatively simple to maintain and capable of yielding an even higher quality of cleanliness than previously obtained. I will also explore several drying techniques available for these systems and other alternatives along with recent improvements made in this technology. When considering any type of cleaning system, a number of variables should be determined before selecting the basic configuration. Some of these variables are: (1) Soil or contaminants being removed from your parts; (2) The level of cleanliness required; (3) The environmental considerations of your area; (4) Maintenance requirements; and (5) Operating costs.

  7. A Modified Controlled Cortical Impact Technique to Model Mild Traumatic Brain Injury Mechanics in Mice

    PubMed Central

    Chen, YungChia; Mao, Haojie; Yang, King H.; Abel, Ted; Meaney, David F.

    2014-01-01

    For the past 25 years, controlled cortical impact (CCI) has been a useful tool in traumatic brain injury (TBI) research, creating injury patterns that includes primary contusion, neuronal loss, and traumatic axonal damage. However, when CCI was first developed, very little was known on the underlying biomechanics of mild TBI. This paper uses information generated from recent computational models of mild TBI in humans to alter CCI and better reflect the biomechanical conditions of mild TBI. Using a finite element model of CCI in the mouse, we adjusted three primary features of CCI: the speed of the impact to achieve strain rates within the range associated with mild TBI, the shape, and material of the impounder to minimize strain concentrations in the brain, and the impact depth to control the peak deformation that occurred in the cortex and hippocampus. For these modified cortical impact conditions, we observed peak strains and strain rates throughout the brain were significantly reduced and consistent with estimated strains and strain rates observed in human mild TBI. We saw breakdown of the blood–brain barrier but no primary hemorrhage. Moreover, neuronal degeneration, axonal injury, and both astrocytic and microglia reactivity were observed up to 8 days after injury. Significant deficits in rotarod performance appeared early after injury, but we observed no impairment in spatial object recognition or contextual fear conditioning response 5 and 8 days after injury, respectively. Together, these data show that simulating the biomechanical conditions of mild TBI with a modified cortical impact technique produces regions of cellular reactivity and neuronal loss that coincide with only a transient behavioral impairment. PMID:24994996

  8. Disposable baby wipes: efficacy and skin mildness.

    PubMed

    Odio, M; Streicher-Scott, J; Hansen, R C

    2001-04-01

    The results of a series of four clinical studies demonstrated that disposable baby wipes were milder to the skin than use of a cotton washcloth and water, recognized as a "gold standard" for skin mildness. Importantly, the baby wipes caused no significant change from the baseline value in any of the skin parameters examined. This observation verified that the test wipes are minimally disruptive to the epidermal barrier and thus suitable for use on intact or compromised, irritated skin. PMID:11917305

  9. Perinatal Risk Factors for Mild Motor Disability

    ERIC Educational Resources Information Center

    Hands, Beth; Kendall, Garth; Larkin, Dawne; Parker, Helen

    2009-01-01

    The aetiology of mild motor disability (MMD) is a complex issue and as yet is poorly understood. The aim of this study was to identify the prevalence of perinatal risk factors in a cohort of 10-year-old boys and girls with (n = 362) and without (n = 1193) MMD. Among the males with MMD there was a higher prevalence of postpartum haemorrhage,…

  10. Subacute to chronic mild traumatic brain injury.

    PubMed

    Mott, Timothy F; McConnon, Michael L; Rieger, Brian P

    2012-12-01

    Although a universally accepted definition is lacking, mild traumatic brain injury and concussion are classified by transient loss of consciousness, amnesia, altered mental status, a Glasgow Coma Score of 13 to 15, and focal neurologic deficits following an acute closed head injury. Most patients recover quickly, with a predictable clinical course of recovery within the first one to two weeks following traumatic brain injury. Persistent physical, cognitive, or behavioral postconcussive symptoms may be noted in 5 to 20 percent of persons who have mild traumatic brain injury. Physical symptoms include headaches, dizziness, and nausea, and changes in coordination, balance, appetite, sleep, vision, and hearing. Cognitive and behavioral symptoms include fatigue, anxiety, depression, and irritability, and problems with memory, concentration and decision making. Women, older adults, less educated persons, and those with a previous mental health diagnosis are more likely to have persistent symptoms. The diagnostic workup for subacute to chronic mild traumatic brain injury focuses on the history and physical examination, with continuing observation for the development of red flags such as the progression of physical, cognitive, and behavioral symptoms, seizure, progressive vomiting, and altered mental status. Early patient and family education should include information on diagnosis and prognosis, symptoms, and further injury prevention. Symptom-specific treatment, gradual return to activity, and multidisciplinary coordination of care lead to the best outcomes. Psychiatric and medical comorbidities, psychosocial issues, and legal or compensatory incentives should be explored in patients resistant to treatment.

  11. Subacute to chronic mild traumatic brain injury.

    PubMed

    Mott, Timothy F; McConnon, Michael L; Rieger, Brian P

    2012-12-01

    Although a universally accepted definition is lacking, mild traumatic brain injury and concussion are classified by transient loss of consciousness, amnesia, altered mental status, a Glasgow Coma Score of 13 to 15, and focal neurologic deficits following an acute closed head injury. Most patients recover quickly, with a predictable clinical course of recovery within the first one to two weeks following traumatic brain injury. Persistent physical, cognitive, or behavioral postconcussive symptoms may be noted in 5 to 20 percent of persons who have mild traumatic brain injury. Physical symptoms include headaches, dizziness, and nausea, and changes in coordination, balance, appetite, sleep, vision, and hearing. Cognitive and behavioral symptoms include fatigue, anxiety, depression, and irritability, and problems with memory, concentration and decision making. Women, older adults, less educated persons, and those with a previous mental health diagnosis are more likely to have persistent symptoms. The diagnostic workup for subacute to chronic mild traumatic brain injury focuses on the history and physical examination, with continuing observation for the development of red flags such as the progression of physical, cognitive, and behavioral symptoms, seizure, progressive vomiting, and altered mental status. Early patient and family education should include information on diagnosis and prognosis, symptoms, and further injury prevention. Symptom-specific treatment, gradual return to activity, and multidisciplinary coordination of care lead to the best outcomes. Psychiatric and medical comorbidities, psychosocial issues, and legal or compensatory incentives should be explored in patients resistant to treatment. PMID:23198672

  12. Aqueous phase processing of secondary organic aerosol from isoprene photooxidation

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Monod, A.; Tritscher, T.; Praplan, A. P.; DeCarlo, P. F.; Temime-Roussel, B.; Quivet, E.; Marchand, N.; Dommen, J.; Baltensperger, U.

    2012-07-01

    Transport of reactive air masses into humid and wet areas is highly frequent in the atmosphere, making the study of aqueous phase processing of secondary organic aerosol (SOA) very relevant. We have investigated the aqueous phase processing of SOA generated from gas-phase photooxidation of isoprene using a smog chamber. The SOA collected on filters was extracted by water and subsequently oxidized in the aqueous phase either by H2O2 under dark conditions or by OH radicals in the presence of light, using a photochemical reactor. Online and offline analytical techniques including SMPS, HR-AMS, H-TDMA, TD-API-AMS, were employed for physical and chemical characterization of the chamber SOA and nebulized filter extracts. After aqueous phase processing, the particles were significantly more hygroscopic, and HR-AMS data showed higher signal intensity at m/z 44 and a lower signal intensity at m/z 43, thus showing the impact of aqueous phase processing on SOA aging, in good agreement with a few previous studies. Additional offline measurement techniques (IC-MS, APCI-MS2 and HPLC-APCI-MS) permitted the identification and quantification of sixteen individual chemical compounds before and after aqueous phase processing. Among these compounds, small organic acids (including formic, glyoxylic, glycolic, butyric, oxalic and 2,3-dihydroxymethacrylic acid (i.e. 2-methylglyceric acid)) were detected, and their concentrations significantly increased after aqueous phase processing. In particular, the aqueous phase formation of 2-methylglyceric acid and trihydroxy-3-methylbutanal was correlated with the consumption of 2,3-dihydroxy-2-methyl-propanal, and 2-methylbutane-1,2,3,4-tetrol, respectively, and an aqueous phase mechanism was proposed accordingly. Overall, the aging effect observed here was rather small compared to previous studies, and this limited effect could possibly be explained by the lower liquid phase OH concentrations employed here, and/or the development of oligomers

  13. Using obsessions as reinforcers with and without mild reductive procedures to decrease inappropriate behaviors of children with autism.

    PubMed

    Charlop-Christy, M H; Haymes, L K

    1996-10-01

    We assessed the effectiveness of using the obsessions of children with autism to reduce their inappropriate behaviors. Baseline consisted of a traditional differential reinforcement of other behaviors (DRO) in which food reinforcers were provided contingent upon a period of nonoccurrence of the inappropriate behaviors. Then, three treatment conditions were assessed using a multielement design. One condition provided objects of obsession as reinforcers for periods of nonoccurrence of the inappropriate behaviors. A second condition also provided the obsessions as reinforcers, but in conjunction with mild reductive procedures (verbal "no", time-out). A final condition used the food reinforcers of baseline, but with mild reductive procedures. Results indicated that all three treatment conditions were more effective than the traditional food DRO of baseline. The most effective condition was the obsessions plus mild reductive procedures. Results are discussed in terms of recommendations for effective treatment planning.

  14. The aqueous stability of a Mars salt analog: Instant Mars

    NASA Astrophysics Data System (ADS)

    Nuding, D. L.; Davis, R. D.; Gough, R. V.; Tolbert, M. A.

    2015-03-01

    Due to their stability in low-temperature conditions, aqueous salt solutions are the favored explanation for potential fluid features observed on present-day Mars. A salt analog was developed to closely match the individual cation and anion concentrations at the Phoenix landing site as reported by the Wet Chemistry Laboratory instrument. "Instant Mars" closely replicates correct relative concentrations of magnesium, calcium, potassium, sodium, perchlorate, chloride, and sulfate ions. A Raman microscope equipped with an environmental cellprobed liquid water uptake and loss by Instant Mars particles in a Mars relevant temperature and relative humidity (RH) environment. Our experiments reveal that Instant Mars particles can form stable, aqueous solutions starting at 56 ± 5% RH between 235 K and 243 K and persist as a metastable, aqueous solution at or above 13 ± 5% RH. Particle levitation using an optical trap examined the phase state and morphology of suspended Instant Mars particles exposed to changing water vapor conditions at room temperature. Levitation experiments indicate that water uptake began at 42 ± 8% RH for Instant Mars particles at 293 K. As RH is decreased at 293 K, the aqueous Instant Mars particles transition into a crystalline solid at 18 ± 7% RH. These combined results demonstrate that Instant Mars can take up water vapor from the surrounding environment and transition into a stable, aqueous solution. Furthermore, this aqueous Instant Mars solution can persist as a metastable, supersaturated solution in low-RH conditions.

  15. The evolution of mild parkinsonian signs in aging.

    PubMed

    Mahoney, Jeannette R; Verghese, Joe; Holtzer, Roee; Allali, Gilles

    2014-10-01

    The progression of mild parkinsonian signs in the absence of idiopathic Parkinson's disease in aging is unclear. This study aims to identify predictors of the evolution of mild parkinsonian signs in non-demented older adults. Two hundred ten participants (76.25 ± 7.10 years, 57% women) were assessed at baseline and 1-year follow-up. Mild parkinsonian signs were defined as the presence of bradykinesia, rigidity and/or rest tremor. Depending upon the presence of these features at baseline and follow-up, participants were divided into one of four groups (no, transient, persistent or new-onset mild parkinsonian signs). Physical function was assessed using gait velocity. Ninety-five participants presented with mild parkinsonian signs at baseline. At 1-year follow-up, 59 demonstrated persistent mild parkinsonian signs, while 36 recovered (i.e., transient). Participants with persistent mild parkinsonian signs were older (79.66 ± 7.15 vs. 75.81 ± 7.37 years, p = 0.01) and evidenced slower gait velocity (90.41 ± 21.46 vs. 109.92 ± 24.32 cm/s, p < 0.01) compared to those with transient mild parkinsonian signs. Gait velocity predicted persistence of mild parkinsonian signs, even after adjustments (OR: 0.96, 95% CI: 0.94-0.98). Fifty-five participants demonstrated new-onset of mild parkinsonian signs. In comparison to participants without mild parkinsonian signs, presence of cardiovascular but not cerebrovascular disease at baseline was associated with new-onset mild parkinsonian signs. Our study reveals that gait velocity was the main predictor of persistent mild parkinsonian signs, whereas cardiovascular disease was associated with new-onset mild parkinsonian signs. These findings suggest a vascular mechanism for the onset of mild parkinsonian signs and a different mechanism, possibly neurodegenerative, for the persistence of mild parkinsonian signs. PMID:25047763

  16. Highly efficient decomposition of organic dye by aqueous-solid phase transfer and in situ photocatalysis using hierarchical copper phthalocyanine hollow spheres.

    PubMed

    Zhang, Mingyi; Shao, Changlu; Guo, Zengcai; Zhang, Zhenyi; Mu, Jingbo; Zhang, Peng; Cao, Tieping; Liu, Yichun

    2011-07-01

    The hierarchical tetranitro copper phthalocyanine (TNCuPc) hollow spheres were fabricated by a simple solvothermal method. The formation mechanism was proposed based on the evolution of morphology as a function of solvothermal time, which involved the initial formation of nanoparticles followed by their self-aggregation to microspheres and transformation into hierarchical hollow spheres by Ostwald ripening. Furthermore, the hierarchical TNCuPc hollow spheres exhibited high adsorption capacity and excellent simultaneously visible-light-driven photocatalytic performance for Rhodamine B (RB) under visible light. A possible mechanism for the "aqueous-solid phase transfer and in situ photocatalysis" was suggested. Repetitive tests showed that the hierarchical TNCuPc hollow spheres maintained high catalytic activity over several cycles, and it had a better regeneration capability under mild conditions.

  17. Isocratic non-aqueous reversed-phase high-performance liquid chromatographic separation of capsanthin and capsorubin in red peppers (Capsicum annuum L.), paprika and oleoresin.

    PubMed

    Weissenberg, M; Schaeffler, I; Menagem, E; Barzilai, M; Levy, A

    1997-01-01

    A simple, rapid high-performance liquid chromatography method has been devised in order to separate and quantify the xanthophylls capsorubin and capasanthin present in red pepper (Capsicum annuum L.) fruits and preparations made from them (paprika and oleoresin). A reversed-phase isocratic non-aqueous system allows the separation of xanthophylls within a few minutes, with detection at 450 nm, using methyl red as internal standard to locate the various carotenoids and xanthophylls found in plant extracts. The selection of extraction solvents, mild saponification conditions, and chromatographic features is evaluated and discussed. The method is proposed for rapid screening of large plant populations, plant selection, as well as for paprika products and oleoresin, and also for nutrition and quality control studies.

  18. Is Mild Dementia Related to Unsafe Street-Crossing Decisions?

    PubMed

    Dommes, Aurélie; Wu, Ya-Huei; Aquino, Jean-Pierre; Pitti-Ferrandi, Hélène; Soleille, Martine; Martineau-Fleury, Sophie; Samson, Michel; Rigaud, Anne-Sophie

    2015-01-01

    The overrepresentation of very old people (75 or older) in pedestrian crash statistics raises the issue of the effects of normal and pathologic ageing on gap-selection difficulties during street crossing. The present study focused on Alzheimer disease, a condition commonly associated with cognitive declines detrimental to daily life activities such as crossing the street. Twenty-five participants with mild dementia and 33 controls carried out a street-crossing task in a simulated environment. They also took a battery of cognitive tests. The mild-dementia group was more likely than the control group to make decisions that led to collisions with approaching cars, especially when the traffic was coming from 2 directions and they were in the far lane. Regression analyses demonstrated that the increased likelihood of collisions in the dementia group was associated with impairments in processing-speed and visual-attention abilities assessed on the Useful Field of View test. This test has already proven useful for predicting driving outcomes, falls, and street-crossing difficulties in healthy old adults, and among drivers with Alzheimer disease. Clinicians are encouraged to use it to help estimate whether a patient can drive, walk, and cross a street safely.

  19. Solubilization of native integral membrane proteins in aqueous buffer by non-covalent chelation with monomethoxy polyethylene glycol (mPEG) polymers

    PubMed Central

    Janaratne, Thamara K.; Okach, Linda; Brock, Ansgar; Lesley, Scott A.

    2011-01-01

    Highly hydrophobic integral membrane proteins (IMPs) are typically purified in excess detergent media, often resulting in rapid inactivation and denaturation of the protein. One promising approach to solve this problem is to couple hydrophilic polymers, such as monomethoxypolyethylene glycol (mPEG) to IMPs under mild conditions in place of detergents. However, the broad application of this approach is hampered by poor reaction efficiencies, low tolerance of detergent stabilized membrane proteins to reaction conditions and a lack of proper site-specific reversible approaches. Here we have developed a straightforward, efficient and mild approach to site-specific non-covalent binding of long-chain polymers to recombinant IMPs. This method uses the hexa-histidine tag (His-Tag) often used for purification of recombinant proteins as an attachment site for mPEGs. Solubility studies performed using five different IMPs confirmed that all tested mPEG-bound IMPs were completely soluble and stable in detergent free aqueous buffer compared to their precipitated native proteins under the identical circumstances. Activity assays and circular dichroism (CD) spectroscopy confirmed the structural integrity of modified IMPs. PMID:21740061

  20. Bacterial Acclimation Inside an Aqueous Battery

    PubMed Central

    Dong, Dexian; Chen, Baoling; Chen, P.

    2015-01-01

    Specific environmental stresses may lead to induced genomic instability in bacteria, generating beneficial mutants and potentially accelerating the breeding of industrial microorganisms. The environmental stresses inside the aqueous battery may be derived from such conditions as ion shuttle, pH gradient, free radical reaction and electric field. In most industrial and medical applications, electric fields and direct currents are used to kill bacteria and yeast. However, the present study focused on increasing bacterial survival inside an operating battery. Using a bacterial acclimation strategy, both Escherichia coli and Bacillus subtilis were acclimated for 10 battery operation cycles and survived in the battery for over 3 days. The acclimated bacteria changed in cell shape, growth rate and colony color. Further analysis indicated that electrolyte concentration could be one of the major factors determining bacterial survival inside an aqueous battery. The acclimation process significantly improved the viability of both bacteria E. coli and B. subtilis. The viability of acclimated strains was not affected under battery cycle conditions of 0.18-0.80 mA cm-2 and 1.4-2.1 V. Bacterial addition within 1.0×1010 cells mL-1 did not significantly affect battery performance. Because the environmental stress inside the aqueous battery is specific, the use of this battery acclimation strategy may be of great potential for the breeding of industrial microorganisms. PMID:26070088

  1. Bacterial Acclimation Inside an Aqueous Battery.

    PubMed

    Dong, Dexian; Chen, Baoling; Chen, P

    2015-01-01

    Specific environmental stresses may lead to induced genomic instability in bacteria, generating beneficial mutants and potentially accelerating the breeding of industrial microorganisms. The environmental stresses inside the aqueous battery may be derived from such conditions as ion shuttle, pH gradient, free radical reaction and electric field. In most industrial and medical applications, electric fields and direct currents are used to kill bacteria and yeast. However, the present study focused on increasing bacterial survival inside an operating battery. Using a bacterial acclimation strategy, both Escherichia coli and Bacillus subtilis were acclimated for 10 battery operation cycles and survived in the battery for over 3 days. The acclimated bacteria changed in cell shape, growth rate and colony color. Further analysis indicated that electrolyte concentration could be one of the major factors determining bacterial survival inside an aqueous battery. The acclimation process significantly improved the viability of both bacteria E. coli and B. subtilis. The viability of acclimated strains was not affected under battery cycle conditions of 0.18-0.80 mA cm(-2) and 1.4-2.1 V. Bacterial addition within 1.0×10(10) cells mL(-1) did not significantly affect battery performance. Because the environmental stress inside the aqueous battery is specific, the use of this battery acclimation strategy may be of great potential for the breeding of industrial microorganisms.

  2. The Croydon Assessment of Learning Study: Prevalence and Educational Identification of Mild Mental Retardation

    ERIC Educational Resources Information Center

    Simonoff, Emily; Pickles, Andrew; Chadwick, Oliver; Gringras, Paul; Wood, Nicky; Higgins, Siobhan; Maney, Julie-Ann; Karia, Nisha; Iqbal, Huma; Moore, Anne

    2006-01-01

    Background: Mild mental retardation is an enduring and impairing condition. Its prevalence has varied widely across different studies from 0.5 to over 8%, with higher rates in completely ascertained samples. The current study estimates the prevalence of low IQ in the mental retardation range (intellectual disability) in a population sample and…

  3. People with Mild to Moderate Intellectual Disability Talking about Their Diabetes and How They Manage

    ERIC Educational Resources Information Center

    Cardol, M.; Rijken, M.; van Schrojenstein Lantman-de Valk, H.

    2012-01-01

    Background: The prevalence of diabetes is relatively high in people with intellectual disability (ID). However, little is known about how people with ID experience having diabetes and how they manage the condition. Method: Seventeen people with mild to moderate ID who have diabetes were interviewed. A framework on illness perceptions having an…

  4. Increasing the Probability of Stimulus Equivalence with Adults with Mild Mental Retardation

    ERIC Educational Resources Information Center

    Saunders, Richard R.; McEntee, Julie, E.

    2004-01-01

    In Experiment 1, 6 adults with mild mental retardation were taught 3 overlapping conditional discriminations in a linear series structure, establishing the possibility of the emergence of 2 stimulus equivalence classes of 4 stimuli per class. Training employed balanced trial types in which the discriminative stimuli were presented in fixed pairs…

  5. Effects of a Mindfulness-Based Smoking Cessation Program for an Adult with Mild Intellectual Disability

    ERIC Educational Resources Information Center

    Singh, Nirbhay N.; Lancioni, Giulio E.; Winton, Alan S. W.; Singh, Ashvind N. A.; Singh, Judy; Singh, Angela D. A.

    2011-01-01

    Smoking is a major risk factor for a number of health conditions and many smokers find it difficult to quit smoking without specific interventions. We developed and used a mindfulness-based smoking cessation program with a 31-year-old man with mild intellectual disabilities who had been a smoker for 17 years. The mindfulness-based smoking…

  6. Writing Impairments in Japanese Patients with Mild Cognitive Impairment and with Mild Alzheimer's Disease

    PubMed Central

    Hayashi, Atsuko; Nomura, Hiroshi; Mochizuki, Ruriko; Ohnuma, Ayumu; Kimpara, Teiko; Suzuki, Kyoko; Mori, Etsuro

    2015-01-01

    Background/Aims We investigated writing abilities in patients with the amnestic type of mild cognitive impairment (aMCI) and mild Alzheimer's disease (AD). To examine the earliest changes in writing function, we used writing tests for both words and sentences with different types of Japanese characters (Hiragana, Katakana, and Kanji). Methods A total of 25 aMCI patients, 38 AD patients, and 22 healthy controls performed writing to dictation for Kana and Kanji words, copied Kanji words, and wrote in response to a picture story task. Analysis of variance was used to test the subject group effects on the scores in the above writing tasks. Results For the written Kanji words, the mild AD group performed worse than the aMCI group and the controls, but there was no difference between the aMCI group and the controls. For the picture story writing task, the mild AD and aMCI groups performed worse than the controls, but the difference between the AD and the aMCI groups was not significant. Conclusions The mild AD group showed defects in writing Kanji characters, and the aMCI group showed impairments in narrative writing. Our study suggests that narrative writing, which demands complex integration of multiple cognitive functions, can be used to detect the subtle writing deficits in aMCI patients. PMID:26483830

  7. Modeling aqueous solubility.

    PubMed

    Butina, Darko; Gola, Joelle M R

    2003-01-01

    This paper describes the development of an aqueous solubility model based on solubility data from the Syracuse database, calculated octanol-water partition coefficient, and 51 2D molecular descriptors. Two different statistical packages, SIMCA and Cubist, were used and the results were compared. The Cubist model, which comprises a collection of rules, each of which has an associated Multiple Linear Regression model (MLR), gave better overall results on a test set of 640 compounds with an overall squared correlation coefficient of 0.74 and an absolute average error of 0.68 log units. Both training and independent test sets had similar distributions of structures in terms of the different functionalities present-60% neutral, 14% acidic, 8% phenolic, 11% monobasic, 4% polybasic, and 3% zwitterionic molecules. Sets were designed by random selection, with 2688 (81%) and 640 (19%) molecules, respectively, forming the training and the test sets.

  8. Development of chiral catalysts for Mukaiyama aldol reactions in aqueous media.

    PubMed

    Kitanosono, Taku; Kobayashi, Shū

    2014-02-01

    Since the discovery of the Mukaiyama aldol reaction in 1973, tremendous efforts have been made to develop a definitive catalyst that catalyzes asymmetric Mukaiyama aldol reactions under mild conditions with broad substrate tolerance. Forty years later, an exhaustive search for a water-compatible Lewis acid was able to uncover the hidden potential of iron(II) and bismuth(III), leading to the establishment of broadly applicable and versatile catalytic systems for asymmetric Mukaiyama aldol reactions in aqueous media. The ternary catalytic system was able to expand the substrate generality considerably as the most distinguished catalyst ever reported. The superiority of this methodology over conventional methods has also been demonstrated in terms of high catalytic activity, simplicity of experimental procedures, and a wide substrate range including aqueous aldehydes, for which the stereochemistry had been regarded as difficult to control. Furthermore, a facile synthesis of the chiral ligand underscores its versatility. The reaction did not proceed at all without use of water. In the postulated mechanism, water plays prominent roles in: (1) producing the active metal complexes with a high water-exchange rate constant (3.2 × 10(6)) to activate substrates effectively and to catalyze the reaction through a rapid proton transfer on the order of picoseconds; (2) facilitating the catalytic turnover with simultaneous desilylation as direct access to aldol adducts or facile recovery of active metal complexes; and (3) stabilizing rigid transition states composed of metal complexes and reactants through entropy-driven aggregation derived from the highest cohesive energy density. PMID:24449534

  9. Comparison of SNOMED CT versus Medcin Terminology Concept Coverage for Mild Traumatic Brain Injury

    PubMed Central

    Montella, Diane; Brown, Steven H.; Elkin, Peter L.; Jackson, James C.; Rosenbloom, S. Trent; Wahner-Roedler, Dietlind; Welsh, Gail; Cotton, Bryan; Guillamondegui, Oscar D.; Lew, Henry; Taber, Katherine H.; Tupler, Larry A.; Vanderploeg, Rodney; Speroff, Theodore

    2011-01-01

    Background: Traumatic Brain Injury (TBI) is a “signature” injury of the current wars in Iraq and Afghanistan. Structured electronic data regarding TBI findings is important for research, population health and other secondary uses but requires appropriate underlying standard terminologies to ensure interoperability and reuse. Currently the U.S. Department of Veterans Affairs (VA) uses the terminology SNOMED CT and the Department of Defense (DOD) uses Medcin. Methods: We developed a comprehensive case definition of mild TBI composed of 68 clinical terms. Using automated and manual techniques, we evaluated how well the mild TBI case definition terms could be represented by SNOMED CT and Medcin, and compared the results. We performed additional analysis stratified by whether the concepts were rated by a TBI expert panel as having High, Medium, or Low importance to the definition of mild TBI. Results: SNOMED CT sensitivity (recall) was 90% overall for coverage of mild TBI concepts, and Medcin sensitivity was 49%, p < 0.001 (using McNemar’s chi square). Positive predictive value (precision) for each was 100%. SNOMED CT outperformed Medcin for concept coverage independent of import rating by our TBI experts. Discussion: SNOMED CT was significantly better able to represent mild TBI concepts than Medcin. This finding may inform data gathering, management and sharing, and data exchange strategies between the VA and DOD for active duty soldiers and veterans with mild TBI. Since mild TBI is an important condition in the civilian population as well, the current study results may be useful also for the general medical setting. PMID:22195156

  10. Pathways of aqueous Cr(VI) attenuation in a slightly alkaline oxic subsurface

    SciTech Connect

    Qafoku, Nikolla; Dresel, P. Evan; McKinley, James P.; Liu, Chongxuan; Heald, Steve M.; Ainsworth, Calvin C.; Phillips, Jerry L.; Fruchter, Jonathan S.

    2009-01-21

    Column experiments combined with geochemical modeling, microscopic inspections and spectroscopic interrogations were conducted with four freshly or naturally aged contaminated sediments with concentrated Cr(VI) waste fluids. The objective was to determine sediment-dependent Cr(VI) desorption extent and rates, Cr(VI) physical location and soil mineral associations, and mechanism(s) of Cr(VI) attenuation under mild alkaline conditions. Results showed that majority of Cr(VI) mass was easily removed from all sediments. Equilibrium site Kd varied from 0 to 0.33 ml g-1 and equilibrium site fraction was greater than 95 %. In addition, long tailings of time-dependent Cr(VI) concentrations above Environmental Protection Agency maximum concentration limit (MCL) of 1.9 µmol L-1, were also observed (kinetic site Kd and desorption reaction half-life varied from 0 to 45 ml g-1, and 76.1 to 126 h, respectively). Aqueous phase pH, particle size distribution and pore water composition contributed to the variability observed among sediments. Microscopic and spectroscopic studies confirmed that Cr was concentrated within fine-grained coatings in small areas rich in phyllosilicates that contained mixed valence [Cr(III)/Cr(VI)]. However, Cr(VI) reduction was neither significant nor complete. The kinetically controlled Cr(VI) desorption may have resulted from the transport (diffusion) of Cr(VI) out of these areas. In summary, at least four pools of Cr(VI) with different leaching behavior might be present in sediments exposed to concentrated waste fluids: i.) The pool of highly mobile and easily removed Cr(VI) (over 95% of total Cr); ii.) The pool of Cr(VI) held in remote sites that provided a long-term continuing source of contaminant Cr; iii.) The pool of reduced immobile Cr(III) which was formed, most likely, by redox reactions of aqueous Cr(VI) and aqueous, sorbed, or structural Fe(II); vi.) The pool of sparingly soluble Cr(VI) phases (e.g., BaCrO4) or solid solutions which did not

  11. Microfluidic culture platform for studying neuronal response to mild to very mild axonal stretch injurya)

    PubMed Central

    Yap, Yiing C.; Dickson, Tracey C.; King, Anna E.; Breadmore, Michael C.; Guijt, Rosanne M.

    2014-01-01

    A new model for studying localised axonal stretch injury is presented, using a microfluidic device to selectively culture axons on a thin, flexible poly (dimethylsiloxane) membrane which can be deflected upward to stretch the axons. A very mild (0.5% strain) or mild stretch injury (5% strain) was applied to primary cortical neurons after 7 days growth in vitro. The extent of distal degeneration was quantified using the degenerative index (DI, the ratio of fragmented axon area to total axon area) of axons fixed at 24 h and 72 h post injury (PI), and immunolabelled for the axon specific, microtubule associated protein-tau. At 24 h PI following very mild injuries (0.5%), the majority of the axons remained intact and healthy with no significant difference in DI when compared to the control, but at 72 h PI, the DI increased significantly (DI = 0.11 ± 0.03). Remarkably, dendritic beading in the somal compartment was observed at 24 h PI, indicative of dying back degeneration. When the injury level was increased (5% stretch, mild injury), microtubule fragmentation along the injured axons was observed, with a significant increase in DI at 24 h PI (DI = 0.17 ± 0.02) and 72 h PI (DI = 0.18 ± 0.01), relative to uninjured axons. The responses observed for both mild and very mild injuries are similar to those observed in the in vivo models of traumatic brain injury, suggesting that this model can be used to study neuronal trauma and will provide new insights into the cellular and molecular alterations characterizing the neuronal response to discrete axonal injury. PMID:25379095

  12. Copper-catalyzed aerobic oxidation of hydroxamic acids leads to a mild and versatile acylnitroso ene reaction.

    PubMed

    Frazier, Charles P; Engelking, Jarred R; Read de Alaniz, Javier

    2011-07-13

    A mild formation of transient acylnitroso intermediates using a copper chloride catalyst and 1 atm of air as the terminal oxidant is described. The mild reaction conditions enable the inter- and intramolecular acylnitroso ene reaction with a wide range of functionalized alkene partners, as well as the first asymmetric variant. Notably, this transformation provides a practical and operationally simple method for effecting allylic amidation using an environmentally benign oxidant and a readily abundant transition metal. PMID:21678942

  13. Serial position effects in mild cognitive impairment.

    PubMed

    Howieson, Diane B; Mattek, Nora; Seeyle, Adriana M; Dodge, Hiroko H; Wasserman, Dara; Zitzelberger, Tracy; Jeffrey, Kaye

    2011-03-01

    Mild cognitive impairment (MCI) is often associated with the preclinical phase of Alzheimer's disease (AD). Special scoring of word-list recall data for serial position has been suggested to improve discrimination of normal aging from dementia. We examined serial position effects in word-list recall for MCI participants compared to Alzheimer patients and controls. Individuals with MCI, like Alzheimer patients, had a diminished primacy effect in recalling words from a list. No alternative scoring system was better than standard scoring of word-list recall in distinguishing MCI patients from controls. Retention weighted scoring improved the discrimination of MCI and AD groups.

  14. Plasmon-driven sequential chemical reactions in an aqueous environment

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Wang, Peijie; Zhang, Zhenglong; Fang, Yurui; Sun, Mengtao

    2014-06-01

    Plasmon-driven sequential chemical reactions were successfully realized in an aqueous environment. In an electrochemical environment, sequential chemical reactions were driven by an applied potential and laser irradiation. Furthermore, the rate of the chemical reaction was controlled via pH, which provides indirect evidence that the hot electrons generated from plasmon decay play an important role in plasmon-driven chemical reactions. In acidic conditions, the hot electrons were captured by the abundant H+ in the aqueous environment, which prevented the chemical reaction. The developed plasmon-driven chemical reactions in an aqueous environment will significantly expand the applications of plasmon chemistry and may provide a promising avenue for green chemistry using plasmon catalysis in aqueous environments under irradiation by sunlight.

  15. Plasmon-driven sequential chemical reactions in an aqueous environment.

    PubMed

    Zhang, Xin; Wang, Peijie; Zhang, Zhenglong; Fang, Yurui; Sun, Mengtao

    2014-06-24

    Plasmon-driven sequential chemical reactions were successfully realized in an aqueous environment. In an electrochemical environment, sequential chemical reactions were driven by an applied potential and laser irradiation. Furthermore, the rate of the chemical reaction was controlled via pH, which provides indirect evidence that the hot electrons generated from plasmon decay play an important role in plasmon-driven chemical reactions. In acidic conditions, the hot electrons were captured by the abundant H(+) in the aqueous environment, which prevented the chemical reaction. The developed plasmon-driven chemical reactions in an aqueous environment will significantly expand the applications of plasmon chemistry and may provide a promising avenue for green chemistry using plasmon catalysis in aqueous environments under irradiation by sunlight.

  16. Plasmon-driven sequential chemical reactions in an aqueous environment

    PubMed Central

    Zhang, Xin; Wang, Peijie; Zhang, Zhenglong; Fang, Yurui; Sun, Mengtao

    2014-01-01

    Plasmon-driven sequential chemical reactions were successfully realized in an aqueous environment. In an electrochemical environment, sequential chemical reactions were driven by an applied potential and laser irradiation. Furthermore, the rate of the chemical reaction was controlled via pH, which provides indirect evidence that the hot electrons generated from plasmon decay play an important role in plasmon-driven chemical reactions. In acidic conditions, the hot electrons were captured by the abundant H+ in the aqueous environment, which prevented the chemical reaction. The developed plasmon-driven chemical reactions in an aqueous environment will significantly expand the applications of plasmon chemistry and may provide a promising avenue for green chemistry using plasmon catalysis in aqueous environments under irradiation by sunlight. PMID:24958029

  17. Mild coarctation of the aorta: to touch or not to touch the patient?

    NASA Astrophysics Data System (ADS)

    Keshavarz-Motamed, Zahra; Randles, Amanda; Rikhtegar Nezami, Farhad; Partida, Ramon; Nakamura, Kenta; Staziaki, Pedro V.; Ghoshhajra, Brian; Bhatt, Ami; Edelman, Elazer R.

    2015-11-01

    Coarctation of the aorta (COA) is an aortic obstruction. A peak-to-peak trans-coarctation pressure gradient (PKdP) of greater than 20 mmHg warns severe COA and the need for interventional/surgical repair. The optimal method and timing of intervention remain uncertain especially for mild COA (PKdP <20 mmHg); even it is unclear if mild COA should be treated at all. Although it was recently suggested that treatment strategies for mild COA may need to be redefined as transcatheter interventions emerge, benefits of such interventions are unclear. We investigated the effects of transcatheter interventions on the aorta and left ventricle (LV) hemodynamics in 11 patients with mild COA using a developed computational fluid dynamics and lumped parameter modeling framework along with particle image velocimetry and clinical measurements. Such interventions can improve aortic hemodynamics to some extent (e.g., time-averaged wall shear stress and kinetic energy were reduced by about 20%). However there is no concomitant effect on the LV hemodynamics (e.g., stroke work and LV pressure were reduced by only less than 4%). Our computational approach can effectively predict clinical conditions. Herein one must question intervention for mild COA, as it has limited utility in reducing myocardial strain.

  18. Prospective memory impairment in mild cognitive impairment: an analytical review.

    PubMed

    Costa, Alberto; Caltagirone, Carlo; Carlesimo, Giovanni Augusto

    2011-12-01

    Mild cognitive impairment (MCI) is a heterogeneous condition characterized by the presence in an otherwise healthy elderly individual of cognitive deficits involving specific domains in the absence of significant functional impairments. Reports indicate that prospective memory (PM), that is, the ability to remember to execute delayed intentions, is impaired in individuals with MCI. The present review discusses the current debate in the literature on PM functioning in MCI by focusing on the relationship between prospective retrieval and retrospective memory functioning. Analysis of the reported evidence revealed that both the prospective component and the retrospective component of PM can be impaired in MCI. Declarative memory dysfunction may account for the retrospective memory impairment, while either reduced executive abilities or a deficit of reflexive mechanisms could explain the prospective component impairment.

  19. Unilateral buckling of elastically restrained rectangular mild steel plates

    NASA Astrophysics Data System (ADS)

    Smith, S. T.; Bradford, M. A.; Oehlers, D. J.

    This paper considers the elastic unilateral buckling of rectangular mild steel plates that are restrained elastically and subjected to bending and axial actions. A variational formulation of the Ritz method using linear combinations of harmonic functions for the buckling deformations is used to establish an eigenproblem to determine the plate local buckling coefficients. The motivation for the study is the retrofit of reinforced concrete beams by gluing and then bolting steel plates to the sides of the beam. Such plates, when acting compositely with the concrete beam, are subjected to predominantly bending and axial actions which may cause unilateral local buckling. Whereas the bolts provide complete restraint against buckling at discrete points, the glue may also inhibit local buckling between these nodal points since it acts as a continuous elastic restraint. The influence of the glue stiffness, support conditions and plate proportions on the unilateral buckling of such plates are assessed.

  20. Bronchodilators for treatment of mild bronchiolitis: a factorial randomised trial.

    PubMed Central

    Wang, E E; Milner, R; Allen, U; Maj, H

    1992-01-01

    A randomised double blind trial was conducted to determine the efficacy of inhaled bronchodilators, salbutamol and ipratropium bromide, compared with placebo in the treatment of bronchiolitis. Patients, who were 2 months to 2 years of age and without underlying cardiac or pulmonary disease, received drug 1 (salbutamol or saline placebo) followed one hour later by drug 2 (ipratropium bromide or placebo). Both agents were administered every four hours. The patients were allocated to one of four groups according to a factorial design. The four groups were similar in demographic characteristics, initial oxygenation, and clinical score. The change in oxygen saturation of recipients of both agents was significantly better than that of recipients of salbutamol alone or ipratropium bromide alone. This change, however, was not statistically different from that of the control group. No difference was observed in the clinical score or hospital duration. Inhaled bronchodilators did not improve the condition of hospitalised mild bronchiolitis. PMID:1533504

  1. Development of microbands in mild steel during cross loading

    NASA Astrophysics Data System (ADS)

    Thuillier, S.; Rauch, E. F.

    1994-06-01

    Mild steel specimens are submitted to a complex strain path (tension-shear sequence). The stress decrease recorded at the beginning of the second path is associated at the grain scale with a localization of the deformation in microbands. These microbands are associated with a single crystallographic slip system and carry the main part of the imposed strain. The prediction of the active slip systems during both the prestrain and the second path with the Taylor and static models leads to a necessary condition for the development of microbands: the slip system having the maximum Schmid factor must have been latent during the prestrain. At high strain level, the material resumes strain hardening and the dislocation structure is then composed of sheets parallel and/or perpendicular to the shear direction. The origin of the flow localization and the transition between the two types of structures, i.e. microbands and dislocation sheets, are then discussed.

  2. Mild Neurocognitive Disorder: An Old Wine in a New Bottle

    PubMed Central

    Stokin, Gorazd B.; Krell-Roesch, Janina; Petersen, Ronald C.; Geda, Yonas E.

    2015-01-01

    Abstract The American Psychiatric Association has recently published the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The DSM-IV category “Dementia, Delirium, Amnestic, and Other Cognitive Disorders” has undergone extensive revision. DSM-5 has renamed this category as “Neurocognitive Disorders” (NCD), which now covers three entities: delirium, major NCD, and mild NCD. The DSM-IV version of mild NCD resembles the DSM-5 version in name only. DSM-IV defined mild NCD based on a single criterion, whereas DSM-5 defines mild NCD by using several cognitive and related criteria. The main difference between mild NCD and the Key International Symposium criteria of mild cognitive impairment (MCI) is that the research work that led to the construct of MCI primarily involved elderly study participants (even though age was not part of the definition of MCI), whereas mild NCD includes acquired cognitive disorders of all age groups. DSM-5 essentially discusses the epidemiology and diagnostic markers of mild NCD by drawing congruence between MCI and mild NCD. The DSM-5 definition of mild NCD is anchored on four criteria and two specifiers. The four criteria refer to cognitive changes, functional activities, and exclusion of delirium and competing mental disorders. The two specifiers are the presumed etiologies of mild NCD and the presence or absence of behavioral problems. While the category “mild NCD” may improve reliability of diagnoses, it has yet to withstand scientific scrutiny to be considered a valid construct. This article reviews the DSM-5 criteria for mild NCD, compares them with the Key International Symposium MCI criteria, and discusses the pros and cons of the mild NCD construct. PMID:26332219

  3. Mild Neurocognitive Disorder: An Old Wine in a New Bottle.

    PubMed

    Stokin, Gorazd B; Krell-Roesch, Janina; Petersen, Ronald C; Geda, Yonas E

    2015-01-01

    The American Psychiatric Association has recently published the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The DSM-IV category "Dementia, Delirium, Amnestic, and Other Cognitive Disorders" has undergone extensive revision. DSM-5 has renamed this category as "Neurocognitive Disorders" (NCD), which now covers three entities: delirium, major NCD, and mild NCD. The DSM-IV version of mild NCD resembles the DSM-5 version in name only. DSM-IV defined mild NCD based on a single criterion, whereas DSM-5 defines mild NCD by using several cognitive and related criteria. The main difference between mild NCD and the Key International Symposium criteria of mild cognitive impairment (MCI) is that the research work that led to the construct of MCI primarily involved elderly study participants (even though age was not part of the definition of MCI), whereas mild NCD includes acquired cognitive disorders of all age groups. DSM-5 essentially discusses the epidemiology and diagnostic markers of mild NCD by drawing congruence between MCI and mild NCD. The DSM-5 definition of mild NCD is anchored on four criteria and two specifiers. The four criteria refer to cognitive changes, functional activities, and exclusion of delirium and competing mental disorders. The two specifiers are the presumed etiologies of mild NCD and the presence or absence of behavioral problems. While the category "mild NCD" may improve reliability of diagnoses, it has yet to withstand scientific scrutiny to be considered a valid construct. This article reviews the DSM-5 criteria for mild NCD, compares them with the Key International Symposium MCI criteria, and discusses the pros and cons of the mild NCD construct.

  4. Mars Aqueous Processing System

    NASA Technical Reports Server (NTRS)

    Berggren, Mark; Wilson, Cherie; Carrera, Stacy; Rose, Heather; Muscatello, Anthony; Kilgore, James; Zubrin, Robert

    2012-01-01

    The goal of the Mars Aqueous Processing System (MAPS) is to establish a flexible process that generates multiple products that are useful for human habitation. Selectively extracting useful components into an aqueous solution, and then sequentially recovering individual constituents, can obtain a suite of refined or semi-refined products. Similarities in the bulk composition (although not necessarily of the mineralogy) of Martian and Lunar soils potentially make MAPS widely applicable. Similar process steps can be conducted on both Mars and Lunar soils while tailoring the reaction extents and recoveries to the specifics of each location. The MAPS closed-loop process selectively extracts, and then recovers, constituents from soils using acids and bases. The emphasis on Mars involves the production of useful materials such as iron, silica, alumina, magnesia, and concrete with recovery of oxygen as a byproduct. On the Moon, similar chemistry is applied with emphasis on oxygen production. This innovation has been demonstrated to produce high-grade materials, such as metallic iron, aluminum oxide, magnesium oxide, and calcium oxide, from lunar and Martian soil simulants. Most of the target products exhibited purities of 80 to 90 percent or more, allowing direct use for many potential applications. Up to one-fourth of the feed soil mass was converted to metal, metal oxide, and oxygen products. The soil residue contained elevated silica content, allowing for potential additional refining and extraction for recovery of materials needed for photovoltaic, semiconductor, and glass applications. A high-grade iron oxide concentrate derived from lunar soil simulant was used to produce a metallic iron component using a novel, combined hydrogen reduction/metal sintering technique. The part was subsequently machined and found to be structurally sound. The behavior of the lunar-simulant-derived iron product was very similar to that produced using the same methods on a Michigan iron

  5. Levothyroxine treatment of mild subclinical hypothyroidism: a review of potential risks and benefits

    PubMed Central

    Javed, Zeeshan; Sathyapalan, Thozhukat

    2016-01-01

    Subclinical hypothyroidism (SCH) is defined as elevated thyroid stimulating hormone (TSH) with normal levels of free triiodothyronine (FT3) and free thyroxine (FT4). SCH is further classified into a milder condition with TSH levels between 4.0 and 10.0 milli-international units (mIU)/l (mild-SCH) and a severe form with TSH >10.0 mIU/l (severe-SCH). SCH is a common problem (prevalence is greater in women than men), which increases further with increasing age and TSH levels. Even though the risk of progression to overt hypothyroidism is higher in patients with severe-SCH, the risk is also significant in patients having mild-SCH; it has been suggested that every twofold rise in serum TSH would increase the risk from 1 to 4%, which further increases to 38% if thyroid antibodies are positive. Current data have shown increased cardiovascular risk in patients with mild-SCH and have demonstrated some benefits of levothyroxine treatment in reducing these events. However, evidence on the association of mild-SCH and musculoskeletal system, cognitive dysfunction, mood disorders, dyslipidaemia, diabetes and goitre is conflicting. Similarly, the discussion regarding the exact upper limit of normal for serum TSH remains controversial. The data have also shown increased risk of adverse pregnancy outcomes in patient with mild-SCH, with some benefits of thyroxine treatment. The recent available guidelines related to management of patients with serum TSH <10 mIU/l have suggested decisions should be made taking into account the age of the patient, associated risk factors and comorbid conditions. This chronicle review assesses current evidence regarding the risks associated and the recommendations related to benefits of levothyroxine treatment in patients having mild-SCH. PMID:26885359

  6. CO2 sequestration through aqueous accelerated carbonation of BOF slag: A factorial study of parameters effects.

    PubMed

    Polettini, Alessandra; Pomi, Raffaella; Stramazzo, Alessio

    2016-02-01

    A factorial study was conducted on basic oxygen furnace slag from a steelmaking industry with the aim of systematically identifying the individual and joint effects of the operating parameters (total pressure, CO2 concentration in the gas phase and temperature) on the CO2 sequestration yield of a direct aqueous carbonation process. Each operating parameter was varied over a range of three levels according to a 3(3) factorial design, resulting in 27 carbonation experiments. The carbonation performance and the changes in particle size and mineralogical characteristics of the slag were investigated in detail. The analysis of the experimental results indicated large effects of the operating factors on CO2 uptake, which was observed to span the range 6.7-53.6 g CO2/100 g slag. The best carbonation performance achieved was particularly significant compared to previous studies, even more considering the relative mild operating conditions adopted (P = 5 bar, C = 40% vol. CO2, T = 50 °C, t = 4 h). The analysis of the solid and liquid phases at the end of the carbonation treatment evidenced significant changes in the physical, chemical and mineralogical composition of the material. In particular, evidence was gained of other elements (Mg, Fe, Mn, Zn) in addition to Ca being intensively involved in the carbonation reactions, with a variety of carbonate phases being produced in addition to calcium carbonate forms. PMID:26686071

  7. Facile aqueous synthesis of β-AgI nanoplates as efficient visible-light-responsive photocatalyst.

    PubMed

    Jiang, Wen; An, Changhua; Liu, Junxue; Wang, Shutao; Zhao, Lianming; Guo, Wenyue; Liu, Jinxiang

    2014-01-01

    Owing to far-ranging industrial applications and theoretical researches, tailored synthesis of well-defined nanocrystals has attracted substantial research interest. Herein, β-AgI nanoplates have been synthesized through a facile polyvinylpyrrolidone (PVP)-assisted-aqueous-solution (PAAS) method under mild conditions. The parametric studies on the effect of ratio of reactants, solvents and surfactants were performed, revealing that a molar ratio of I(-) to Ag(+) of 1.2 in deionized water and the presence of appropriate PVP as stabilizing agent can stimulate the preferred orientation growth of AgI nanoplates. The as-synthesized AgI nanoplates exhibit excellent photocatalytic activity and enhanced durability towards the degradation of organics, i.e., rhodamine B (RhB), under visible light illumination in comparison with corresponding bulk nanoparticles. A possible photocatalytic reaction mechanism was discussed, revealing O2˙(-) and h(+) are main reactive species and free ˙OH radicals in solution also contribute to the degradation reaction. The superior photocatalytic performance renders the as-achieved AgI nanoplates promising candidates for applications in the fields of environmental purification or water disinfection. The present work opens an avenue to the synthesis of other shaped silver halide nanophotocatalysts.

  8. CO2 sequestration through aqueous accelerated carbonation of BOF slag: A factorial study of parameters effects.

    PubMed

    Polettini, Alessandra; Pomi, Raffaella; Stramazzo, Alessio

    2016-02-01

    A factorial study was conducted on basic oxygen furnace slag from a steelmaking industry with the aim of systematically identifying the individual and joint effects of the operating parameters (total pressure, CO2 concentration in the gas phase and temperature) on the CO2 sequestration yield of a direct aqueous carbonation process. Each operating parameter was varied over a range of three levels according to a 3(3) factorial design, resulting in 27 carbonation experiments. The carbonation performance and the changes in particle size and mineralogical characteristics of the slag were investigated in detail. The analysis of the experimental results indicated large effects of the operating factors on CO2 uptake, which was observed to span the range 6.7-53.6 g CO2/100 g slag. The best carbonation performance achieved was particularly significant compared to previous studies, even more considering the relative mild operating conditions adopted (P = 5 bar, C = 40% vol. CO2, T = 50 °C, t = 4 h). The analysis of the solid and liquid phases at the end of the carbonation treatment evidenced significant changes in the physical, chemical and mineralogical composition of the material. In particular, evidence was gained of other elements (Mg, Fe, Mn, Zn) in addition to Ca being intensively involved in the carbonation reactions, with a variety of carbonate phases being produced in addition to calcium carbonate forms.

  9. Mild pyrolysis of selectively oxidized coals

    SciTech Connect

    Hippo, E.J.

    1991-01-01

    The primary objective of this study is to investigate the removal organic sulfur from selectively oxidized Illinois coals using mild thermal/chemical processes. Work completed this quarter includes the investigation of the mild pyrolysis of unoxidized coals plus a selection of selectively oxidized coals. In addition the effect of particle size and extent of oxidation on pyrolysis was investigated. Some preliminary data concerning pyrolysis under vacuum and ambient pressure was also obtained. Work completed this quarter supports the following conclusions: (1) Desulfurization of unoxidized coals increases with increasing pyrolysis temperature and correlates with the loss of volatile matter. (2) Particle size did not influence the extent of desulfurization significantly. (3) Removing pyrite prior to pyrolysis helps to achieve a lower sulfur product beyond that expected from the removal of pyrite alone. (4) The extent of selective oxidation in teh pretreatment step did not effect the level of desulfurization obtained by pyrolysis alone. However this factor was important in the desulfurization obtained with supercritical methanol (SCM)/base. (5) Up to 84% of the sulfur has been removed from the IBC 101 coal by combining selective oxidation and SCM/base reactions. (6) Evidence for regressive reactions between volatilized sulfur compounds and partially desulfurized products was obtained by studying how changes in pyrolysis pressure effected the product sulfur content.

  10. ENCOAL mild coal gasification project. Annual report

    SciTech Connect

    Not Available

    1993-10-01

    This document is the combination of the fourth quarter report (July--September 1993) and the 1993 annual report for the ENCOAL project. The following pages include the background and process description for the project, brief summaries of the accomplishments for the first three quarters, and a detailed fourth quarter report. Its purpose is to convey the accomplishments and current progress of the project. ENCOAL Corporation, has completed the construction of a mild gasification demonstration plant at Triton Coal Company`s Buckskin Mine near Gillette, Wyoming. The process, using Liquids From Coal (LFC) technology developed by SMC and SGI International, utilizes low-sulfur Powder River Basin coal to produce two new fuels, Process Derived Fuel (PDF) and Coal Derived Liquids (CDL). ENCOAL submitted an application to the US Department of Energy (DOE) in August 1989, soliciting joint funding of the project in the third round of the Clean Coal Technology Program. The project was selected by DOE in December, 1989 and the Cooperative Agreement approved in September, 1990. Construction, commissioning, and start-up of the ENCOAL mild coal gasification facility was completed in June of 1992, and the project is currently in the operations phase. Some plant modifications have been required and are discussed in this report.

  11. Mild behavioral impairment and risk of dementia

    PubMed Central

    Taragano, FE; Allegri, RF; Krupitzki, H; Sarasola, D; Serrano, CM; Loñ, L; Lyketsos, CG

    2009-01-01

    Background Mild cognitive impairment (MCI) is a transitional state between normal ageing and dementia, at least for some patients. Behavioral symptoms in MCI are associated with a higher risk of dementia, but their association with dementia risk in patients without MCI is unknown. Mild Behavioral Impairment (MBI) refers to a late life syndrome with prominent psychiatric and related behavioral symptoms in the absence of prominent cognitive symptoms, which may also be a dementia prodrome. Objective To compare MCI and MBI patients and to estimate the risk of dementia development in these two groups. Method A consecutive series of 358 patients (239 with MCI; and 119 with MBI) presenting to an outpatient general hospital specialty clinic were followed for up to 5 years until conversion to dementia or censoring. Results 34% of MCI patients and over 70% of patients with MBI developed dementia (Logrank p=0.011). MBI patients without cognitive symptoms were more likely to develop dementia (Logrank p<0.001). MBI patients were more likely to develop dementia due to frontotemporal degeneration (FTD) as opposed to Alzheimer’s dementia (AD). Conclusion MBI appears to be a transitional state between normal ageing and dementia. MBI (specifically those without cognitive symptoms) may confer a higher risk for dementia than MCI and is likely an FTD prodrome in many cases. These findings have implications for the early detection, prevention, and treatment of patients with dementia in late life, by focusing on the emergence of new behavioral symptoms. PMID:19323967

  12. Bismuth catalysts in aqueous media.

    PubMed

    Kobayashi, Shū; Ueno, Masaharu; Kitanosono, Taku

    2012-01-01

    Several bismuth-catalyzed synthetic reactions, which proceed well in aqueous media, are discussed. Due to increasing demand of water as a solvent in organic synthesis, catalysts that can be used in aqueous media are becoming more and more important. Although bismuth Lewis acids are not very stable in water, it has been revealed that they can be stabilized by basic ligands. Chiral amine and related basic ligands combined with bismuth Lewis acids are particularly useful in asymmetric catalysis in aqueous media. On the other hand, bismuth hydroxide is stable and works as an efficient catalyst for carbon-carbon bond-forming reactions in water. PMID:21769719

  13. Aqueous photolysis of niclosamide

    USGS Publications Warehouse

    Graebing, P.W.; Chib, J.S.; Hubert, T.D.; Gingerich, W.H.

    2004-01-01

    The photodegradation of [14C]niclosamide was studied in sterile, pH 5, 7, and 9 buffered aqueous solutions under artificial sunlight at 25.0 A? 1.0 A?C. Photolysis in pH 5 buffer is 4.3 times faster than in pH 9 buffer and 1.5 times faster than in pH 7 buffer. In the dark controls, niclosamide degraded only in the pH 5 buffer. After 360 h of continuous irradiation in pH 9 buffer, the chromatographic pattern of the degradates was the same regardless of which ring contained the radiolabel. An HPLC method was developed that confirmed these degradates to be carbon dioxide and two- and four-carbon aliphatic acids formed by cleavage of both aromatic rings. Carbon dioxide was the major degradate, comprising 40% of the initial radioactivity in the 360 h samples from both labels. The other degradates formed were oxalic acid, maleic acid, glyoxylic acid, and glyoxal. In addition, in the chloronitroaniline-labeled irradiated test solution, 2-chloro-4-nitroaniline was observed and identified after 48 h of irradiation but was not detected thereafter. No other aromatic compounds were isolated or observed in either labeled test system.

  14. Aqueous chlorination of resorcinol

    USGS Publications Warehouse

    Heasley, V.L.; Burns, M.D.; Kemalyan, N.A.; Mckee, T.C.; Schroeter, H.; Teegarden, B.R.; Whitney, S.E.; Wershaw, R. L.

    1989-01-01

    An investigation of the aqueous chlorination (NaOCl) of resorcinol is reported. The following intermediates were detected in moderate to high yield at different pH values and varying percentages of chlorination: 2-chloro-, 4-chloro-, 2,4-dichloro-, 4,6-dichloro- and 2,4,6-trichlororesorcinol. Only trace amounts of the intermediates were detected when the chlorination was conducted in the presence of phosphate buffer. This result has significant implications since resorcinol in phosphate buffer has been used as a model compound in several recent studies on the formation of chlorinated hydrocarbons during chlorination of drinking water. Relative rates of chlorination were determined for resorcinol and several of the chlorinated resorcinols. Resorcinol was found to chlorinate only three times faster than 2,4,6-trichlororesorcinol. The structure 2,4,6-trichlororesorcinol was established as a monohydrate even after sublimation. A tetrachloro or pentachloro intermediate was not detected, suggesting that the ring-opening step of such an intermediate must be rapid. ?? 1989.

  15. Aqueous photooxidation of isoprene hydroxyhydroperoxides (ISOPOOH)

    NASA Astrophysics Data System (ADS)

    Rivera, J. C.; Zhao, R.; Lee, A.; Abbatt, J.; Keutsch, F. N.

    2015-12-01

    Under pristine atmospheric conditions, Isoprene Hydroxyhydroperoxides (ISOPOOHs) are the main first generation products of isoprene oxidation. ISOPOOHs contain two highly hydrophilic functional groups that enable it to partition into atmospheric waters. There it can be further oxidized or act as a source of OH. In order to study this process, we conducted aqueous photooxidation experiments aimed at understanding the role of ISOPOOH, and hydroperoxides in general, in atmospheric waters. ISOPOOH standards were irradiated in the presence of H2O2 in order to simulate aqueous processing. The solutions were analyzed online via HR-ToF-CIMS and HR-ToF AMS. We were able to determine that the main products of ISOPOOH oxidation in water are isoprene epoxydiols (IEPOX). Side products formed during the photooxidation were detected as well, including products of direct photolysis and highly oxygenated compounds. ISOPOOH was also confirmed to produce OH in the condensed phase both, via direct photolysis of the peroxide bond and as a co-product of IEPOX formation. Competition experiments with Levoglucosan allowed for the measurement of ISOPOOHs OH reaction rate constant in the condensed phase. Finally, experiments using an OH trap enabled the measurement of the yield of OH from ISOPOOH photolysis that escapes the solvent cage. Together these experiments provide new insights into the role that hydrophilic products of atmospheric oxidation, especially peroxides, can play in SOA formation via aqueous processing.

  16. Aqueous biphasic microprinting approach to tissue engineering

    PubMed Central

    Tavana, Hossein; Takayama, Shuichi

    2011-01-01

    We summarize a recently developed microtechnology for printing biomaterials on biological surfaces. The technique is based on the use of immiscible aqueous solutions of two biopolymers and allows spatially defined placement of cells and biomolecules suspended in the denser aqueous phase on existing cell layers and extracellular matrix hydrogel surfaces maintained in the second phase. Printing takes place due to an extremely small interfacial tension and density difference between the two aqueous phases. The contact-free printing process ensures that both printed cells and the underlying cell monolayer maintain full viability and functionality. The technique accommodates both arbitrarily shaped patterns and microarrays of cells and bioreagents. The capability to print cells and small molecules on existing cell layers enables unique interrogations of the effects of cell-cell and cell-material interaction on cell fate and function. Furthermore, the very gentle conditions and the ability to directly pattern nongel embedded cells over cells make this technology appealing to tissue engineering applications where patterned multicellar organization with minimal scaffolding materials is needed, such as in dense tissues of the skeletal muscle and liver. PMID:21522494

  17. Controlled Synthesis of Functional Silver Nanoparticles Dispersible in Aqueous and Non-Aqueous Medium.

    PubMed

    Pandey, Prem C; Singh, Richa

    2015-08-01

    The synthesis of silver nanoparticles (AgNPs) controlled by active participation of 3-Amino-propyltrimethoxysilane (3-APTMS) and 3-Glycidoxypropyltrimethoxysilane (GPTMS) is found to be function of two sequential processes; (1) interaction of metal ions with 3-APTMS and (2) interaction of GPTMS with 3-APTMS capped metal ions. The mechanism of such process as evidenced from visual photographs, UV-visible spectroscopy, energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM) is reported. The experimental findings demonstrate the followings; (1) There is faster interaction of 3-APTMS with gold ions as compared to that of silver ions under similar conditions, (2) Methanolic solution of GPTMS undergo interaction with 3-APTMS and the same is facilitated in the presence of 3-APTMS treated silver ions, (3) The size of as synthesized AgNPs increases with an increase in 3-APTMS concentration whereas reverse is recorded for change in GPTMS concentration, (4) The molar ratio of 3-APTMS/GPTMS control the nanogeometry as well as the dispersibility of AgNPs in both aqueous and non aqueous media, (5) The dispersion ability of AgNPs is attributed to the hydrophobic alkyl chain of the reaction product of GPTMS and 3-APTMS (6) AgNPs shows absorption maxima as a function of refractive index of the medium and (7) The as synthesized AgNPs behave as peroxidase mimetic in both aqueous and non-aqueous medium justifying the potential typical applications.

  18. CAPSULE REPORT: AQUEOUS MERCURY TREATMENT

    EPA Science Inventory

    This report describes established technologies and identifies evolving methods for treating aqueous mercury. The information provided encompasses full-, pilot- and bench-scale treatment results as presented in the technical literature. The report describes alternative technologi...

  19. Mechanical Agitation For Aqueous Cleaning

    NASA Technical Reports Server (NTRS)

    Morgan, Gene E.; Hosking, Timothy J.

    1995-01-01

    Cleaning basket placed in aqueous cleaning solution mechanically agitated by air spring. Compressed air at oscillating pressure supplied to air spring to produce repeated vertical motion of cleaning basket.

  20. Coal desulfurization by aqueous chlorination

    NASA Technical Reports Server (NTRS)

    Kalvinskas, J. J.; Vasilakos, N.; Corcoran, W. H.; Grohmann, K.; Rohatgi, N. K. (Inventor)

    1982-01-01

    A method of desulfurizing coal is described in which chlorine gas is bubbled through an aqueous slurry of coal at low temperature below 130 degrees C., and at ambient pressure. Chlorinolysis converts both inorganic and organic sulfur components of coal into water soluble compounds which enter the aqueous suspending media. The media is separated after chlorinolysis and the coal dechlorinated at a temperature of from 300 C to 500 C to form a non-caking, low-sulfur coal product.

  1. Flow of Aqueous Humor

    MedlinePlus

    ... Grant Terms & Conditions Patent & Intellectual Property Policy For Current Awardees FAQs Our Funding Philosophy News Science News Publications Newsletters Multimedia Press Releases Media Coverage Media Kit Events Contact Main menu Disease Toolkit Disease Toolkit Which ...

  2. Photochemistry of aqueous pyruvic acid.

    PubMed

    Griffith, Elizabeth C; Carpenter, Barry K; Shoemaker, Richard K; Vaida, Veronica

    2013-07-16

    The study of organic chemistry in atmospheric aerosols and cloud formation is of interest in predictions of air quality and climate change. It is now known that aqueous phase chemistry is important in the formation of secondary organic aerosols. Here, the photoreactivity of pyruvic acid (PA; CH3COCOOH) is investigated in aqueous environments characteristic of atmospheric aerosols. PA is currently used as a proxy for α-dicarbonyls in atmospheric models and is abundant in both the gas phase and the aqueous phase (atmospheric aerosols, fog, and clouds) in the atmosphere. The photoreactivity of PA in these phases, however, is very different, thus prompting the need for a mechanistic understanding of its reactivity in different environments. Although the decarboxylation of aqueous phase PA through UV excitation has been studied for many years, its mechanism and products remain controversial. In this work, photolysis of aqueous PA is shown to produce acetoin (CH3CHOHCOCH3), lactic acid (CH3CHOHCOOH), acetic acid (CH3COOH), and oligomers, illustrating the progression from a three-carbon molecule to four-carbon and even six-carbon molecules through direct photolysis. These products are detected using vibrational and electronic spectroscopy, NMR, and MS, and a reaction mechanism is presented accounting for all products detected. The relevance of sunlight-initiated PA chemistry in aqueous environments is then discussed in the context of processes occurring on atmospheric aerosols.

  3. All-aqueous multiphase microfluidics

    PubMed Central

    Song, Yang; Sauret, Alban; Cheung Shum, Ho

    2013-01-01

    Immiscible aqueous phases, formed by dissolving incompatible solutes in water, have been used in green chemical synthesis, molecular extraction and mimicking of cellular cytoplasm. Recently, a microfluidic approach has been introduced to generate all-aqueous emulsions and jets based on these immiscible aqueous phases; due to their biocompatibility, these all-aqueous structures have shown great promises as templates for fabricating biomaterials. The physico-chemical nature of interfaces between two immiscible aqueous phases leads to unique interfacial properties, such as an ultra-low interfacial tension. Strategies to manipulate components and direct their assembly at these interfaces needs to be explored. In this paper, we review progress on the topic over the past few years, with a focus on the fabrication and stabilization of all-aqueous structures in a multiphase microfluidic platform. We also discuss future efforts needed from the perspectives of fluidic physics, materials engineering, and biology for fulfilling potential applications ranging from materials fabrication to biomedical engineering. PMID:24454609

  4. Interaction of gold nanoparticles mediated by captopril and S-nitrosocaptopril: the effect of manganese ions in mild acid medium.

    PubMed

    Iglesias, Emilia; Prado-Gotor, Rafael

    2015-01-01

    We report herein results regarding reactivity and assembly of citrate-capped gold nanoparticles (AuNPs) mediated by captopril (cap) and S-nitrosocaptopril (NOcap), two angiotensin converting enzyme inhibitors and antihypertensive agents. The results were compared with that of cysteine (Cys), a thiol-containing amino acid found in plasma. The interparticle interactions were characterized by monitoring the evolution of the surface plasmon resonance band using the spectrophotometric method. The original gold nanoparticles were efficiently modified by small amounts of Mn(+2) ions, which are adsorbed onto the surface of 15.4 nm citrate-capped gold nanoparticles, giving rise to manganese-gold nanoparticles (Mn-AuNPs) that, in mild acid medium, have proved to be highly sensitive and a rapid colorimetric detection method for thiols. Depending on the concentration of the Mn(+2) ions the aggregation of AuNPs can be rapidly induced. The kinetics of the assembly process has been studied. Good first-order kinetics has been observed, with the exception of captopril-mediated nanoparticle aggregation at low concentration of either cap or acid. The rate of Cys-mediated assembly of gold nanoparticles in aqueous 10 mM acetic acid is more than 20-times faster than pure AuNPs and concentrations of Cys as low as 34 nM can be detected in less than 40 min under conditions of stable Mn-AuNPs. Similar effects were observed with cap or NOcap. The assembly-disassembly reversibility is shown with cap and NOcap and depends highly on pH.

  5. South: in the mild southern tradition

    SciTech Connect

    Price, T.L.

    1980-01-01

    Trends in the development of current and future energy resources in the southern states of the U.S. are reviewed. The south has the advantages of a mild climate and abundant sources of natural gas, coal, and hydro power, however, the supply and distribution of energy are primarily controlled by private and federal monopolies. The Tennessee Valley Authority (TVA) has a program for funding 100,000 solar domestic hot water systems plus low interest loans for wood heaters, zero interest conservation loans, and financing of passive solar homes. TVA will also construct a large passive solar complex. Other applications of solar technology discussed include installation in a brewery, apartment buildings, abandoned city housing, a duplex, an environmental center, a planned community, and a kiln company.

  6. Recent developments in Chevron mild isocracking

    SciTech Connect

    Fuchs, M.J.; Powell, B.E.; Tolberg, R.S.; Saito, Y.

    1985-01-01

    The use of Chevron's dual-catalyst mild hydrocracking technology has enabled Nippon Petroleum Refining Company (NPRC) to produce excellent yields of good-quality mid-distillate from vacuum gas oil (VGO) in an existing VGO desulfurizer at its Muroran Refinery. This technology enables refiners to take advantage of underutilized desulfurization capacity for hydrocracking with minimal additional capital investment. The Muroran unit has been in this high-conversion mode since June 1982 and has operated in the range of 10-30 liquid volume (LV) percent synthetic conversion with yields up to 48 LV percent of 680 F cut-point diesel and lighter products. The details of this operation are discussed. Laboratory pilot plant data are also presented for two different feedbacks. The amount of recoverable diesel and its quality are strong functions of the feed boiling range, synthetic conversion, and plant pressure.

  7. Mildly Recycled Pulsars at High-Energies

    NASA Astrophysics Data System (ADS)

    Pellizzoni, A.

    2011-08-01

    Mildly recyled pulsars (MRP), conventionally defined as neutron star having spin period in the 20-100 ms range and surface magnetic field <1011 Gauss, probably rise from binary systems (disrupted or not) with an intermediate or an high mass companion. Despite their relatively low spin-down energies compared to the ``fully'' recycled millisecond pulsars (arising from common low mass X-ray binaries), nearby MRPs can be detected by deep X-ray observations and by timing analysis of the very long data span provided by gamma-ray space detectors. The discovery of peculiar timing and spectral properties, possibly transitional, of the MRPs can be of the utmost importance to link different classes of neutron stars and study their evolution.

  8. Recovery of responses during mild punishment1

    PubMed Central

    Rachlin, Howard

    1966-01-01

    Pigeons were punished with mild shock for pecking during one of two components of a multiple schedule. They eventually recovered so that they pecked at the same rate during both components. In one experiment they were extinguished after recovering. When punishment was maintained during extinction, they extinguished faster during the punished, than during the unpunished component. When punishment was stopped during extinction, they extinguished faster during the unpunished than during the previously punished component. In another experiment, punishment was programmed first during neither of the two components, then during one, then during both, and finally during the other component. The extent of recovery decreased with each successive cycle. It is concluded that, if transient emotional states are ignored, reward and punishment are symmetrical in their effects. PMID:16811293

  9. Mild coal pretreatment to improve liquefaction reactivity

    SciTech Connect

    Miller, R.L.

    1991-01-01

    This report describes work completed during the fourth quarter of a three year project to study the effects of mild chemical pretreatment on coal dissolution reactivity during low severity liquefaction or coal/oil coprocessing. The overall objective of this research is to elucidate changes in the chemical and physical structure of coal by pretreating with methanol or other simple organic solvent and a trace amount of hydrochloric acid and measure the influence of these changes on coal dissolution reactivity. This work is part of a larger effort to develop a new coal liquefaction or coal/oil coprocessing scheme consisting of three main process steps: (1) mile pretreatment of the feed coal to enhance dissolution reactivity and dry the coal, (2) low severity thermal dissolution of the pretreated coal to obtain a very reactive coal-derived residual material amenable to upgrading, and (3) catalytic upgrading of the residual products to distillate liquids.

  10. Mild desalination of various raw water streams.

    PubMed

    Groot, C K; van den Broek, W B P; Loewenberg, J; Koeman-Stein, N; Heidekamp, M; de Schepper, W

    2015-01-01

    For chemical industries, fresh water availability is a pre-requisite for sustainable operation. However, in many delta areas around the world, fresh water is scarce. Therefore, the E4 Water project (www.e4water.eu) comprises a case study at the Dow site in Terneuzen, The Netherlands, which is designed to develop commercial applications for mild desalination of brackish raw water streams from various origins to enable reuse in industry or agriculture. This study describes an effective two-stage work process, which was used to narrow down a broad spectrum of desalination technologies to a selection of the most promising techniques for a demonstration pilot at 2-4 m³/hour. Through literature study, laboratory experiments and multi-criteria analysis, nanofiltration and electrodialysis reversal were selected, both having the potential to attain the objectives of E4Water at full scale.

  11. Monitoring of Aqueous Fullerene Dispersions by Thermal-Lens Spectrometry

    NASA Astrophysics Data System (ADS)

    Mikheev, I. V.; Volkov, D. S.; Proskurnin, M. A.; Korobov, M. V.

    2015-06-01

    Aqueous fullerene solutions (dispersions) are very promising materials of biomedicine and biotechnology. Of importance are the traceability of their production and characterization of their optical and colloidal properties. Thermal-lens spectrometry, as a method suitable for both optical and thermophysical studies, was used to elucidate the forms of non-modified fullerenes in their aqueous dispersions and to determine low concentrations of and fullerenes. It was shown that the residual amounts of toluene in aqueous fullerene dispersions made according to the solvent-exchange protocol could be detected by thermal lensing. As a result, the technique for the production of aqueous fullerene dispersions was improved compared to the existing data providing higher fullerene concentrations. The limits of detection of and fullerenes are approximately , which are 20-fold lower compared to conventional spectrophotometry. The distinction between aqueous fullerene dispersions in comparison with organic solutions of fullerenes caused by the formation of large clusters is shown by the comparison of transient and steady-state calibration curves for aqueous and organic fullerene solutions and model reference systems under various thermal-lens excitation conditions. The advantages of thermal lensing for such colloidal systems are discussed.

  12. The small chill: mild hypothermia for cardioprotection?

    PubMed

    Tissier, Renaud; Chenoune, Mourad; Ghaleh, Bijan; Cohen, Michael V; Downey, James M; Berdeaux, Alain

    2010-12-01

    Reducing the heart's temperature by 2-5°C is a potent cardioprotective treatment in animal models of coronary artery occlusion. The anti-infarct benefit depends upon the target temperature and the time at which cooling is instituted. Protection primarily results from cooling during the ischaemic period, whereas cooling during reperfusion or beyond offers little protection. In animal studies, protection is proportional to both the depth and duration of cooling. An optimal cooling protocol must appreciably shorten the normothermic ischaemic time to effectively salvage myocardium. Patients presenting with acute myocardial infarction could be candidates for mild hypothermia since the current door-to-balloon time is typically 90 min. But they would have to be cooled quickly shortly after their arrival. Several strategies have been proposed for ultra-fast cooling, but most like liquid ventilation and pericardial perfusion are too invasive. More feasible strategies might include cutaneous cooling, peritoneal lavage with cold solutions, and endovascular cooling with intravenous thermodes. This last option has been investigated clinically, but the results have been disappointing possibly because the devices lacked capacity to cool the patient quickly or cooling was not implemented soon enough. The mechanism of hypothermia's protection has been assumed to be energy conservation. However, whereas deep hypothermia clearly preserves ATP, mild hypothermia has only a modest effect on ATP depletion during ischaemia. Some evidence suggests that intracellular signalling pathways might be responsible for the protection. It is unknown how cooling could trigger these pathways, but, if true, then it might be possible to duplicate cooling's protection pharmacologically. PMID:20621922

  13. Application of maghemite nanoparticles as sorbents for the removal of Cu(II), Mn(II) and U(VI) ions from aqueous solution in acid mine drainage conditions

    NASA Astrophysics Data System (ADS)

    Etale, Anita; Tutu, Hlanganani; Drake, Deanne C.

    2016-06-01

    The adsorptive removal of Cu(II), Mn(II) and U(VI) by maghemite nanoparticles (NPs) was investigated under acid mine drainage (AMD) conditions to assess NP potential for remediating AMD-contaminated water. The effects of time, NP and metal concentration, as well as manganese and sulphate ions were quantified at pH 3. Adsorption of all three ions was rapid, and equilibrium was attained in 5 min or less. 56 % of Cu, 53 % of Mn and 49 % of U were adsorbed. In addition, adsorption efficiencies were enhanced by ≥10 % in the presence of manganese and sulphate ions, although Cu sorption was reduced in 1:2 Cu-to-Mn solutions. Adsorption also increased with pH: 86 % Cu, 62 % Mn and 77 % U were removed from solution at pH 9 and increasing initial metal concentrations. Increasing NP concentrations did not, however, always increase metal removal. Kinetics data were best described by a pseudo-second-order model, implying chemisorption, while isotherm data were better fitted by the Freundlich model. Metal removal by NPs was then tested in AMD-contaminated surface and ground water. Removal efficiencies of up to 46 % for Cu and 54 % for Mn in surface water and 8 % for Cu and 50 % for Mn in ground water were achieved, confirming that maghemite NPs can be applied for the removal of these ions from AMD-contaminated waters. Notably, whereas sulphates may increase adsorption efficiencies, high Mn concentrations in AMD will likely inhibit Cu sorption.

  14. Mild dehydration impairs cognitive performance and mood of men.

    PubMed

    Ganio, Matthew S; Armstrong, Lawrence E; Casa, Douglas J; McDermott, Brendon P; Lee, Elaine C; Yamamoto, Linda M; Marzano, Stefania; Lopez, Rebecca M; Jimenez, Liliana; Le Bellego, Laurent; Chevillotte, Emmanuel; Lieberman, Harris R

    2011-11-01

    The present study assessed the effects of mild dehydration on cognitive performance and mood of young males. A total of twenty-six men (age 20·0 (sd 0·3) years) participated in three randomised, single-blind, repeated-measures trials: exercise-induced dehydration plus a diuretic (DD; 40 mg furosemide); exercise-induced dehydration plus placebo containing no diuretic (DN); exercise while maintaining euhydration plus placebo (EU; control condition). Each trial included three 40 min treadmill walks at 5·6 km/h, 5 % grade in a 27·7°C environment. A comprehensive computerised six-task cognitive test battery, the profile of mood states questionnaire and the symptom questionnaire (headache, concentration and task difficulty) were administered during each trial. Paired t tests compared the DD and DN trials resulting in >1 % body mass loss (mean 1·59 (sd 0·42) %) with the volunteer's EU trial (0·01 (sd 0·03) %). Dehydration degraded specific aspects of cognitive performance: errors increased on visual vigilance (P = 0·048) and visual working memory response latency slowed (P = 0·021). Fatigue and tension/anxiety increased due to dehydration at rest (P = 0·040 and 0·029) and fatigue during exercise (P = 0·026). Plasma osmolality increased due to dehydration (P < 0·001) but resting gastrointestinal temperature was not altered (P = 0·238). In conclusion, mild dehydration without hyperthermia in men induced adverse changes in vigilance and working memory, and increased tension/anxiety and fatigue.

  15. Human capabilities, mild autism, deafness and the morality of embryo selection.

    PubMed

    Jaarsma, Pier; Welin, Stellan

    2013-11-01

    A preimplantation genetic test to discriminate between severe and mild autism spectrum disorder might be developed in the foreseeable future. Recently, the philosophers Julian Savulescu and Guy Kahane claimed that there are strong reasons for prospective parents to make use of such a test to prevent the birth of children who are disposed to autism or Asperger's disorder. In this paper we will criticize this claim. We will discuss the morality of selection for mild autism in embryo selection in a hypothetical in vitro fertilization (IVF) situation where preimplantation genetic diagnosis is performed and compare this with a similar selection for congenital deafness. To do this we first discuss relevant human differences. We then introduce the principle of human capabilities (PC) and compare this principle with the principle of procreative beneficence (PB) introduced by Savulescu and Kahane. We apply the two principles to selection for mild autism and selection for congenital deafness. We argue that PC allows for the selection for mild autism but rules out selection for congenital deafness. PB will not give clear answers; the ruling of PB depends to a large extent on expected social, cultural and political developments. We will argue that PC is preferable to PB. We will discuss arguments for the value of mild autism for individuals who have this condition and argue that they are able to lead a life with human dignity provided autism-friendly social circumstances are present. Neither PC nor PB yields strong reasons for prospective parents to seek to prevent the birth of children who are disposed to mild autism spectrum disorder.

  16. Human capabilities, mild autism, deafness and the morality of embryo selection.

    PubMed

    Jaarsma, Pier; Welin, Stellan

    2013-11-01

    A preimplantation genetic test to discriminate between severe and mild autism spectrum disorder might be developed in the foreseeable future. Recently, the philosophers Julian Savulescu and Guy Kahane claimed that there are strong reasons for prospective parents to make use of such a test to prevent the birth of children who are disposed to autism or Asperger's disorder. In this paper we will criticize this claim. We will discuss the morality of selection for mild autism in embryo selection in a hypothetical in vitro fertilization (IVF) situation where preimplantation genetic diagnosis is performed and compare this with a similar selection for congenital deafness. To do this we first discuss relevant human differences. We then introduce the principle of human capabilities (PC) and compare this principle with the principle of procreative beneficence (PB) introduced by Savulescu and Kahane. We apply the two principles to selection for mild autism and selection for congenital deafness. We argue that PC allows for the selection for mild autism but rules out selection for congenital deafness. PB will not give clear answers; the ruling of PB depends to a large extent on expected social, cultural and political developments. We will argue that PC is preferable to PB. We will discuss arguments for the value of mild autism for individuals who have this condition and argue that they are able to lead a life with human dignity provided autism-friendly social circumstances are present. Neither PC nor PB yields strong reasons for prospective parents to seek to prevent the birth of children who are disposed to mild autism spectrum disorder. PMID:23334404

  17. Tau Reduction Diminishes Spatial Learning and Memory Deficits after Mild Repetitive Traumatic Brain Injury in Mice

    PubMed Central

    Cheng, Jason S.; Craft, Ryan; Yu, Gui-Qiu; Ho, Kaitlyn; Wang, Xin; Mohan, Geetha; Mangnitsky, Sergey; Ponnusamy, Ravikumar; Mucke, Lennart

    2014-01-01

    Objective Because reduction of the microtubule-associated protein Tau has beneficial effects in mouse models of Alzheimer's disease and epilepsy, we wanted to determine whether this strategy can also improve the outcome of mild traumatic brain injury (TBI). Methods We adapted a mild frontal impact model of TBI for wildtype C57Bl/6J mice and characterized the behavioral deficits it causes in these animals. The Barnes maze, Y maze, contextual and cued fear conditioning, elevated plus maze, open field, balance beam, and forced swim test were used to assess different behavioral functions. Magnetic resonance imaging (MRI, 7 Tesla) and histological analysis of brain sections were used to look for neuropathological alterations. We also compared the functional effects of this TBI model and of controlled cortical impact in mice with two, one or no Tau alleles. Results Repeated (2-hit), but not single (1-hit), mild frontal impact impaired spatial learning and memory in wildtype mice as determined by testing of mice in the Barnes maze one month after the injury. Locomotor activity, anxiety, depression and fear related behaviors did not differ between injured and sham-injured mice. MRI imaging did not reveal focal injury or mass lesions shortly after the injury. Complete ablation or partial reduction of tau prevented deficits in spatial learning and memory after repeated mild frontal impact. Complete tau ablation also showed a trend towards protection after a single controlled cortical impact. Complete or partial reduction of tau also reduced the level of axonopathy in the corpus callosum after repeated mild frontal impact. Interpretation Tau promotes or enables the development of learning and memory deficits and of axonopathy after mild TBI, and tau reduction counteracts these adverse effects. PMID:25551452

  18. [Status of mild hypertension guidelines in Japan and abroad].

    PubMed

    Matsuoka, Hiroaki

    2008-08-01

    Historically patients with systolic blood pressure level 140 to 159 mmHg or diastolic blood pressure level 90 to 99 mmHg had been defined as mild hypertension. However, the word of mild hypertension is not used in recent guidelines, such as JNC 7 and ESH/ESC 2007, although it is still used in JSH2004 and BHS IV. Patients with mild hypertension in JSH2004 are diagnosed as high risk hypertension if these patients are complicated cardiovascular organ damage, cardiovascular disease, or diabetes mellitus etc. Personally, I think the word of mild hypertension should be changed to another word or applied to patients with low risk hypertension. PMID:18700542

  19. THE MECHANISM OF AQUEOUS HUMOR FORMATION INFERRED FROM CHEMICAL STUDIES ON BLOOD-AQUEOUS HUMOR DYNAMICS

    PubMed Central

    Kinsey, V. Everett; Grant, W. Morton

    1942-01-01

    The importance of considering the effect of a possible flow out of the anterior chamber before inferring any mechanism of aqueous humor formation from the relative concentration of a substance in the aqueous humor and plasma under equilibrium conditions has been stressed. Several processes to account for the chemical equilibria between aqueous humor and blood based on the ultrafiltration and secretion hypotheses with a possible simultaneous loss of aqueous humor by flow have been outlined. On the basis of these processes, equations were formulated which would relate the rates of transfer into and out of the anterior chamber to the ratio of concentration of a substance in the aqueous to that in the blood at various intervals after its introduction into the blood. The explanation of equilibrium ratios above and below one for aqueous constituents is made apparent from the mathematical formulations. For each substance tested a determination was made of the best fit when the concentration in the aqueous humor is plotted against time. This fit was obtained by plotting the rate of transfer in against the rate of transfer out of the anterior chamber for all of the experimentally found concentration ratios on the basis of both the ultrafiltration and secretory hypotheses. Two sets of values were obtained from these calculations, one set for each hypothesis. The substantial agreement of all the experimental data with an assumed rate of leakage out of the anterior chamber of approximately 4 c. mm. per minute was shown to be compatible only with the idea that all the monovalent electrolytes tested entered the anterior chamber as a result of secretory process. It could not be decided from these chemical studies whether the non-electrolytes and the one multivalent electrolyte tested enter the anterior chamber by ultrafiltration or secretion. Experimental findings from other sources were cited which would suggest that non-electrolytes enter the anterior chamber as a result of

  20. Fenton chemistry at aqueous interfaces

    PubMed Central

    Enami, Shinichi; Sakamoto, Yosuke; Colussi, Agustín J.

    2014-01-01

    In a fundamental process throughout nature, reduced iron unleashes the oxidative power of hydrogen peroxide into reactive intermediates. However, notwithstanding much work, the mechanism by which Fe2+ catalyzes H2O2 oxidations and the identity of the participating intermediates remain controversial. Here we report the prompt formation of O=FeIVCl3− and chloride-bridged di-iron O=FeIV·Cl·FeIICl4− and O=FeIV·Cl·FeIIICl5− ferryl species, in addition to FeIIICl4−, on the surface of aqueous FeCl2 microjets exposed to gaseous H2O2 or O3 beams for <50 μs. The unambiguous identification of such species in situ via online electrospray mass spectrometry let us investigate their individual dependences on Fe2+, H2O2, O3, and H+ concentrations, and their responses to tert-butanol (an ·OH scavenger) and DMSO (an O-atom acceptor) cosolutes. We found that (i) mass spectra are not affected by excess tert-butanol, i.e., the detected species are primary products whose formation does not involve ·OH radicals, and (ii) the di-iron ferryls, but not O=FeIVCl3−, can be fully quenched by DMSO under present conditions. We infer that interfacial Fe(H2O)n2+ ions react with H2O2 and O3 >103 times faster than Fe(H2O)62+ in bulk water via a process that favors inner-sphere two-electron O-atom over outer-sphere one-electron transfers. The higher reactivity of di-iron ferryls vs. O=FeIVCl3− as O-atom donors implicates the electronic coupling of mixed-valence iron centers in the weakening of the FeIV–O bond in poly-iron ferryl species. PMID:24379389

  1. Reduction kinetics of aqueous U(VI) in acidic chloride brines to uraninite by methane, hydrogen or C-graphite under hydrothermal conditions: Implications for the genesis of unconformity-related uranium ore deposits

    NASA Astrophysics Data System (ADS)

    Dargent, Maxime; Truche, Laurent; Dubessy, Jean; Bessaque, Gilles; Marmier, Hervé

    2015-10-01

    The formation of hydrothermal uranium ore deposits involves the reduction of dissolved U(VI)(aq) to uraninite. However, the nature of the reducing agent and the kinetics of such a process are currently unknown. These questions are addressed through dedicated experiments performed under conditions relevant for the genesis of unconformity-related uranium (URU) deposits. We tested the efficiency of the following potential reductants supposed to be involved in the reaction: H2, CH4, C-graphite and dissolved Fe(II). Results demonstrate the great efficiency of H2, CH4 and C-graphite to reduce U(VI)(aq) into uraninite in acidic chloride brines, unlike dissolved Fe(II). Times needed for H2 (1.4 bar), CH4 (2.4 bar) and C-graphite (water/carbon mass ratio = 10) to reduce 1 mM of U(VI)(aq) in an acidic brine (1 m LiCl, pH ≈ 1 fixed by HCl) to uraninite at 200 °C are 12 h, 3 days and 4 months, respectively. The effects of temperature (T) between 100 °C and 200 °C, H2 partial pressure (0.14, 1.4, and 5.4 bar), salinity (0.1, 1 and 3.2 m LiCl) and pH at 25 °C (0.8 and 3.3) on the reduction rate were also investigated. Results show that increasing temperature and H2 partial pressure increase the reaction rate, whereas increasing salinity or pH have the reverse effect. The reduction of uranyl to uraninite follows an apparent zero-order with respect to time, whatever the considered electron donor. From the measured rate constants, the following values of activation energy (Ea), depending on the nature of the electron donor, have been derived: EaC-graphite = 155 ± 3 kJ mol-1, EaCH4 = 143 ± 6 kJ mol-1, and EaH2 = 124 ± 15 kJ mol-1 at T < 150 °C and 32 ± 6 kJ mol-1 at T > 150 °C. An empirical relationship between the reaction rate, the hydrogen partial pressure, the uranyl speciation, and the temperature is also proposed. This allows an estimation of the time of formation of a giant U ore deposit such as McArthur River (Canada). The duration of the mineralizing event is

  2. Aqueous solution synthesis of Pt-M (M = Fe, Co, Ni) bimetallic nanoparticles and their catalysis for the hydrolytic dehydrogenation of ammonia borane.

    PubMed

    Wang, Shuai; Zhang, Duo; Ma, Yanyun; Zhang, Hui; Gao, Jing; Nie, Yuting; Sun, Xuhui

    2014-08-13

    Platinum-based bimetallic nanocatalysts have attracted much attention due to their high-efficiency catalytic performance in energy-related applications such as fuel cell and hydrogen storage, for example, the hydrolytic dehydrogenation of ammonia borane (AB). In this work, a simple and green method has been demonstrated to successfully prepare Pt-M (M = Fe, Co, Ni) NPs with tunable composition (nominal Pt/M atomic ratios of 4:1, 1:1, and 1:4) in aqueous solution under mild conditions. All Pt-M NPs with a small size of 3-5 nm show a Pt fcc structure, suggesting the bimetallic formation (alloy and/or partial core-shell), examined by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray absorption fine structure (XAFS) analysis. The catalytic activities of Pt-M NPs in the hydrolytic dehydrogenation of AB reveal that Pt-Ni NPs with a ratio of 4:1 show the best catalytic activity and even better than that of pure Pt NPs when normalized to Pt molar amount. The Ni oxidation state in Pt-Ni NPs has been suggested to be responsible for the corresponding catalytic activity for hydrolytic dehydrogenation of AB by XAFS study. This strategy for the synthesis of Pt-M NPs is simple and environmentally benign in aqueous solution with the potential for scale-up preparation and the in situ catalytic reaction. PMID:25058566

  3. Cartilage Tissue Engineering Application of Injectable Gelatin Hydrogel with In Situ Visible-Light-Activated Gelation Capability in Both Air and Aqueous Solution

    PubMed Central

    Lin, Hang; Cheng, Anthony Wai-Ming; Alexander, Peter G.; Beck, Angela M.

    2014-01-01

    Chondroprogenitor cells encapsulated in a chondrogenically supportive, three-dimensional hydrogel scaffold represents a promising, regenerative approach to articular cartilage repair. In this study, we have developed an injectable, biodegradable methacrylated gelatin (mGL)–based hydrogel capable of rapid gelation via visible light (VL)–activated crosslinking in air or aqueous solution. The mild photocrosslinking conditions permitted the incorporation of cells during the gelation process. Encapsulated human-bone-marrow-derived mesenchymal stem cells (hBMSCs) showed high, long-term viability (up to 90 days) throughout the scaffold. To assess the applicability of the mGL hydrogel for cartilage tissue engineering, we have evaluated the efficacy of chondrogenesis of the encapsulated hBMSCs, using hBMSCs seeded in agarose as control. The ability of hBMSC-laden mGL constructs to integrate with host tissues after implantation was further investigated utilizing an in vitro cartilage repair model. The results showed that the mGL hydrogel, which could be photopolymerized in air and aqueous solution, supports hBMSC growth and TGF-β3-induced chondrogenesis. Compared with agarose, mGL constructs laden with hBMSCs are mechanically stronger with time, and integrate well with native cartilage tissue upon implantation based on push-out mechanical testing. VL-photocrosslinked mGL scaffold thus represents a promising scaffold for cell-based repair and resurfacing of articular cartilage defects. PMID:24575844

  4. Aqueous phase synthesis of upconversion nanocrystals through layer-by-layer epitaxial growth for in vivo X-ray computed tomography.

    PubMed

    Li, Feifei; Li, Chunguang; Liu, Jianhua; Liu, Xiaomin; Zhao, Lan; Bai, Tianyu; Yuan, Qinghai; Kong, Xianggui; Han, Yu; Shi, Zhan; Feng, Shouhua

    2013-08-01

    Lanthanide-doped core-shell upconversion nanocrystals (UCNCs) have tremendous potential for applications in many fields, especially in bio-imaging and medical therapy. As core-shell UCNCs are mostly synthesized in organic solvents, tedious organic-aqueous phase transfer processes are usually needed for their use in bio-applications. Herein, we demonstrate the first example of one-step synthesis of highly luminescent core-shell UCNCs in the "aqueous" phase under mild conditions using innocuous reagents. A microwave-assisted approach allowed for layer-by-layer epitaxial growth of a hydrophilic NaGdF4 shell on NaYF4:Yb, Er cores. During this process, surface defects of the nanocrystals could be gradually passivated by the homogeneous shell deposition, resulting in obvious enhancement in the overall upconversion emission efficiency. In addition, the up-down conversion dual-mode luminescent NaYF4:Yb, Er@NaGdF4:Ce, Ln (Eu, Tb, Sm, Dy) nanocrystals were also synthesized to further validate the successful formation of the core-shell structure. More significantly, based on their superior solubility and stability in water solution, high upconversion efficiency and Gd-doped predominant X-ray absorption, the as-prepared NaYF4:Yb, Er@NaGdF4 core-shell UCNCs exhibited high contrast in in vitro cell imaging and in vivo X-ray computed tomography (CT) imaging, demonstrating great potential as multiplexed luminescent biolabels and CT contrast agents.

  5. ASSESSMENT OF LIQUID EMULSION MEMBRANE FOR CLEAN UP OF AQUEOUS WASTE EFFLUENTS FROM HAZARDOUS ELEMENTS

    SciTech Connect

    El-Reefy, Sohair A.; Selim, Y.T.; Hassan, M.A.; Aly, H.F.

    2003-02-27

    Four liquid emulsion membrane (LEM) systems are given to remove different hazardous elements such as uranium, thorium, cobalt, copper, lead, and cadmium from different aqueous waste effluents. The optimum conditions for use of these systems are deduced. The potentiality of LEM for removal of hazardous pollutants from aqueous waste solutions is given.

  6. Flow measurements in a model of the mildly curved femoral artery of man

    NASA Technical Reports Server (NTRS)

    Back, L. H.; Kwack, E. Y.; Crawford, D. W.

    1990-01-01

    The effects of curvature on the flow rate near the wall in the vicinity of the mildly curved femoral artery of man, and on the pressure distributions along the curved segment, were investigated using glass and tygon flow models constructed to conform to the shape of the femoral angiogram of a human subject. The test fluid was 33 percent aqueous sucrose. Steady flow observations, made using a dye flow visualization system, revealed a flow pattern like that observed in coiled pipes. A double helical type flow was found to develop, with converging streamlines in the wall vicinity from the upper and lower plane of curvature merging asymptotically along the inner curvature in a stable manner. Pressure measurements for steady flow revealed progressively larger pressure drops with distance along the entrance region of the curved segment, relative to that for a straight lumen.

  7. Diminished supraspinal pain modulation in patients with mild traumatic brain injury

    PubMed Central

    Shukla, Shivshil; Yang, Eric; Canlas, Bryan; Kadokana, Mawj; Heald, Jason; Davani, Ariea; Song, David; Lin, Lisa; Polston, Greg; Tsai, Alice; Lee, Roland

    2016-01-01

    Background Chronic pain conditions are highly prevalent in patients with mild traumatic brain injury. Supraspinal diffuse axonal injury is known to dissociate brain functional connectivity in these patients. The effect of this dissociated state on supraspinal pain network is largely unknown. A functional magnetic resonance imaging study was conducted to compare the supraspinal pain network in patients with mild traumatic brain injury to the gender and age-matched healthy controls with the hypothesis that the functional connectivities of the medial prefrontal cortices, a supraspinal pain modulatory region to other pain-related sensory discriminatory and affective regions in the mild traumatic brain injury subjects are significantly reduced in comparison to healthy controls. Results The mild traumatic brain injury group (N = 15) demonstrated significantly (P < 0.01, cluster threshold > 150 voxels) less activities in the thalamus, pons, anterior cingulate cortex, insula, dorsolateral prefrontal cortex, and medial prefrontal cortices than the healthy control group (N = 15). Granger Causality Analyses (GCA) indicated while the left medial prefrontal cortices of the healthy control group cast a noticeable degree of outward (to affect) causality inference to multiple pain processing related regions, this outward inference pattern was not observed in the mild traumatic brain injury group. On the other hand, only patients’ bilateral anterior cingulate cortex received multiple inward (to be affected) causality inferences from regions including the primary and secondary somatosensory cortices and the inferior parietal lobe. Resting state functional connectivity analyses indicated that the medial prefrontal cortices of the mild traumatic brain injury group demonstrated a significantly (P < 0.01, F = 3.6, cluster size > 150 voxels) higher degree of functional connectivity to the inferior parietal lobe, premotor and secondary somatosensory cortex

  8. Making sense of nonsense: experiences of mild cognitive impairment.

    PubMed

    Beard, Renée L; Neary, Tara M

    2013-01-01

    Alzheimer's disease (AD) is a stigmatised condition popularly assumed to be a death sentence for diagnosed individuals. Consequently, people with AD are often deemed incapable (and perhaps unworthy) of contributing to the social discourse surrounding their illness experience. Data from qualitative interviews with 18 people diagnosed with the potential precursor of AD known as mild cognitive impairment (MCI) are examined. Using grounded theory methods, analysis revealed overarching themes of uncertainty concerning definitions of memory loss, MCI, and AD as well as distinctions between normal ageing and dementia. While this confusion over the terminology and prognosis mirrors the lack of scientific consensus about nosology and appropriate treatment regimens, such ambiguity creates social and psychological tensions for diagnosed individuals. Arguably, participants' unequivocal fear of and subsequent desire to differentiate their experiences from Alzheimer's, however, stems from the exclusively negative social constructions of AD. Drawing from Goffman, these findings demonstrate the psychosocial impact of 'framing contests' and how 'courtesy stigma' can apply not only to associated persons but also associated conditions, such as MCI to AD. Given the underlying nosological creep - or medicalisation - of the recent diagnostic guidelines proposing two new pre-dementia stages, understanding the illness narratives of MCI is critical.

  9. Interference Impacts Working Memory in Mild Cognitive Impairment

    PubMed Central

    Aurtenetxe, Sara; García-Pacios, Javier; del Río, David; López, María E.; Pineda-Pardo, José A.; Marcos, Alberto; Delgado Losada, Maria L.; López-Frutos, José M.; Maestú, Fernando

    2016-01-01

    Mild cognitive impairment (MCI) is considered a transitional stage between healthy aging and dementia, specifically Alzheimer's disease (AD). The most common cognitive impairment of MCI includes episodic memory loss and difficulties in working memory (WM). Interference can deplete WM, and an optimal WM performance requires an effective control of attentional resources between the memoranda and the incoming stimuli. Difficulties in handling interference lead to forgetting. However, the interplay between interference and WM in MCI is not well-understood and needs further investigation. The current study investigated the effect of interference during a WM task in 20 MCIs and 20 healthy elder volunteers. Participants performed a delayed match-to-sample paradigm which consisted in two interference conditions, distraction and interruption, and one control condition without any interference. Results evidenced a disproportionate impact of interference on the WM performance of MCIs, mainly in the presence of interruption. These findings demonstrate that interference, and more precisely interruption, is an important proxy for memory-related deficits in MCI. Thus, the current findings reveal novel evidence regarding the causes of WM forgetting in MCI patients, associated with difficulties in the mechanisms of attentional control. PMID:27790082

  10. Effect of acute mild dehydration on cognitive-motor performance in golf.

    PubMed

    Smith, Mark F; Newell, Alex J; Baker, Mistrelle R

    2012-11-01

    Whether mild dehydration (-1 to 3% body mass change [ΔBM]) impairs neurophysiological function during sport-specific cognitive-motor performance has yet to be fully elucidated. To investigate this within a golfing context, 7 low-handicap players (age: 21 ± 1.1 years; mass: 76.1 ± 11.8 kg; stature: 1.77 ± 0.07 m; handicap: 3.0 ± 1.2) completed a golf-specific motor and cognitive performance task in a euhydrated condition (EC) and dehydrated condition (DC) (randomized counterbalanced design; 7-day interval). Dehydration was controlled using a previously effective 12-hour fluid restriction, monitored through ΔBM and urine color assessment (UCOL). Mild dehydration reduced the mean BM by 1.5 ± 0.5% (p = 0.01), with UCOL increasing from 2 (EC) to 4 (DC) (p = 0.02). Mild dehydration significantly impaired motor performance, expressed as shot distance (114.6 vs. 128.6 m; p < 0.001) and off-target accuracy (7.9 vs. 4.1 m; p = 0.001). Cognitive performance, expressed as the mean error in distance judgment to target increased from 4.1 ± 3.0 m (EC) to 8.8 ± 4.7 m (DC) (p < 0.001). The findings support those of previous research that indicates mild dehydration (-1 to 2% ΔBM) significantly impairs cognitive-motor task performance. This study is the first to show that mild dehydration can impair distance, accuracy, and distance judgment during golf performance.

  11. 21 CFR 522.1881 - Sterile prednisolone acetate aqueous suspension.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... milliliter of sterile aqueous suspension contains 25 milligrams of prednisolone acetate. (b) Sponsor. See No.... (1) The drug is indicated in the treatment of dogs, cats, and horses for conditions requiring an anti... therapy. The drug is administered to dogs and cats intramuscularly at a dosage level of 10 to...

  12. 21 CFR 522.1881 - Sterile prednisolone acetate aqueous suspension.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... milliliter of sterile aqueous suspension contains 25 milligrams of prednisolone acetate. (b) Sponsor. See No.... (1) The drug is indicated in the treatment of dogs, cats, and horses for conditions requiring an anti... therapy. The drug is administered to dogs and cats intramuscularly at a dosage level of 10 to...

  13. Electrodeposition of Californium Using Isobutanol and Aqueous Ammonium Acetate

    NASA Astrophysics Data System (ADS)

    Matoš, Milan; Boll, Rose A.; Phelps, Clarice E.; Torrico, Matthew N.; van Cleve, Shelley M.; Lewis, Benjamin E.

    2013-10-01

    Californium sources and targets are used in many applications in research and industry. Molecular deposition (commonly referred to as electrodeposition) is an experimental technique suitable for production of californium thin films. We are investigating molecular depositions using isobutanol and aqueous ammonium acetate solvents at various conditions to optimize for the best deposition efficiency and repeatability. Results of those tests will be presented.

  14. Biomechanical strategies implemented to compensate for mild leg length discrepancy during gait.

    PubMed

    Resende, Renan A; Kirkwood, Renata N; Deluzio, Kevin J; Cabral, Silvia; Fonseca, Sérgio T

    2016-05-01

    Although mild leg length discrepancy is related to lower limb injuries, there is no consensus regarding its effects on the biomechanics of the lower limbs during gait. Biomechanical data of 19 healthy participants were collected while they walked under different conditions as described: (1) control condition-wearing flat thick sandals; (2) short limb condition-wearing a flat thick sandal on the left and a flat thin sandal on the right foot; (3) long limb condition: wearing flat thin sandal on the left and flat thick sandal on the right foot. The thick and thin sandals had 1.45cm of mean thickness difference. The right lower limb data were analyzed for all conditions. Ankle, knee, hip and pelvis kinematics and internal moments were measured with a motion capture system and six force platforms. Principal component analysis was used to compare differences between conditions. The scores of the principal components were compared between conditions using one-way repeated measures ANOVA. Twelve gait variables were different between conditions: rearfoot dorsiflexion and inversion (p<0.001); ankle dorsiflexion and inversion moments (p<0.001); knee flexion angle and moment (p<0.001); knee adduction moment (p<0.001); hip flexion angle and moment (p<0.001); hip adduction angle (p=0.001) and moment (p=0.022); and pelvic ipsilateral drop (p<0.001). Mild leg length discrepancy caused compensatory changes during gait, apparently to equalize the functional length of the lower limbs. However, these strategies did not fully succeed, since both short and long limb conditions affected pelvic motion in the frontal plane. These results suggest that mild leg length discrepancy should not be overlooked in clinical settings. PMID:27131193

  15. Get Well Care: Guidelines for Programs Serving Mildly Ill Children.

    ERIC Educational Resources Information Center

    Montanari, Ellen Orton, Ed.

    Although child care programs for mildly ill children are proliferating around the country, very few states have developed regulations for these types of programs, and no states have developed standards or guidelines. Based upon this concern, a group of medical and early childhood professionals, parents, and directors of programs for mildly ill…

  16. Predicting Mild and Severe Husband-to-Wife Physical Aggression.

    ERIC Educational Resources Information Center

    Pan, Helen S.; And Others

    1994-01-01

    Estimated odds of mild and severe husband-to-wife physical aggression in 11,870 white men. Being younger, having lower income, and having alcohol problem significantly increased odds of either mild or severe physical aggression. Drug problem uniquely increased risk of severe physical aggression. Marital discord and depression further increased…

  17. Mild Aphasia: Is This the Place for an Argument?

    ERIC Educational Resources Information Center

    Armstrong, Elizabeth; Fox, Sarah; Wilkinson, Ray

    2013-01-01

    Purpose: Individuals with mild aphasia often report significant disruption to their communication despite seemingly minor impairment. This study explored this phenomenon through examining conversations of a person with mild aphasia engaging in argumentation--a skill she felt had significantly deteriorated after her stroke. Method: A person with…

  18. Low Elevated Lead Levels and Mild Mental Retardation.

    ERIC Educational Resources Information Center

    Marlowe, Mike; And Others

    To investigate the relation between low level lead absorption and mild mental retardation, hair lead concentrations were compared in a group of 40 mildly retarded children "etiology unknown" with a control group of 20 children. Children with probable cause for retardation were excluded from the sample as were children with a history of lead…

  19. Impaired Verb Fluency: A Sign of Mild Cognitive Impairment

    ERIC Educational Resources Information Center

    Ostberg, Per; Fernaeus, Sven-Erik; Hellstrom, Ake; Bogdanovic, Nenad; Wahlund, Lars Olof

    2005-01-01

    We assessed verb fluency vs. noun and letter-based fluency in 199 subjects referred for cognitive complaints including Subjective Cognitive Impairment, Mild Cognitive Impairment, and Alzheimer's disease. ANCOVAs and factor analyses identified verb, noun, and letter-based fluency as distinct tasks. Verb fluency performance in Mild Cognitive…

  20. Mild-split SUSY with flavor

    NASA Astrophysics Data System (ADS)

    Eliaz, Latif; Giveon, Amit; Gudnason, Sven Bjarke; Tsuk, Eitan

    2013-10-01

    In the framework of a gauge mediated quiver-like model, the standard model flavor texture can be naturally generated. The model — like the MSSM — has furthermore a region in parameter space where the lightest Higgs mass is fed by heavy stop loops, which in turn sets the average squark mass scale near 10 - 20TeV. We perform a careful flavor analysis to check whether this type of mild-split SUSY passes all flavor constraints as easily as envisioned in the original type of split SUSY. Interestingly, it turns out to be on the border of several constraints, in particular, the branching ratio of μ → eγ and, if order one complex phases are assumed, also ɛ K , neutron and electron EDM. Furthermore, we consider unification as well as dark matter candidates, especially the gravitino. Finally, we provide a closed-form formula for the soft masses of matter in arbitrary representations of any of the gauge groups in a generic quiver-like model with a general messenger sector.

  1. Mild cognitive impairment: a concept in evolution

    PubMed Central

    Petersen, Ronald C.; Caracciolo, Barbara; Brayne, Carol; Gauthier, Serge; Jelic, Vesna; Fratiglioni, Laura

    2014-01-01

    The construct of mild cognitive impairment (MCI) has evolved over the past 10 years since the publication of the new MCI definition at the Key Symposium in 2003, but the core criteria have remained unchanged. The construct has been extensively used worldwide, both in clinical and research settings, to define the grey area between intact cognitive functioning and clinical dementia. A rich set of data regarding occurrence, risk factors, and progression of MCI has been generated. Discrepancies between studies can be mostly explained by differences in the operationalization of the criteria, differences in the setting where the criteria have been applied, selection of subjects, and length of follow-up in longitudinal studies. Major controversial issues that remain to be further explored are: algorithmic versus clinical classification, reliability of clinical judgment, temporal changes in cognitive performances, and predictivity of putative biomarkers. Some suggestions to further develop the MCI construct include the tailoring of the clinical criteria to specific populations and to specific contexts. The addition of biomarkers to the clinical phenotypes is promising but requires deeper investigation. Translation of findings from the specialty clinic to the population setting, although challenging, will enhance uniformity of outcomes. More longitudinal population-based studies on cognitive aging and MCI need to be performed to clarify all these issues. PMID:24605806

  2. Mild Cognitive Impairment: Pathology and mechanisms

    PubMed Central

    Mufson, Elliott J.; Binder, Lester; Counts, Scott E.; DeKosky, Steven T.; deTolledo-Morrell, Leyla; Ginsberg, Stephen D.; Ikonomovic, Milos D.; Perez, Sylvia E.; Scheff, Stephen W.

    2012-01-01

    Mild cognitive impairment (MCI) is rapidly becoming one of the most common clinical manifestations affecting the elderly. The pathologic and molecular substrate of people diagnosed with MCI is not well established. Since MCI is a human specific disorder and neither the clinical nor the neuropathological course appears to follows a direct linear path, it is imperative to characterize neuropathology changes in the brains of people who came to autopsy with a well-characterized clinical diagnosis of MCI. Herein, we discuss findings derived from clinical pathologic studies of autopsy cases with various subtypes of MCI antemortem. The heterogeneity of clinical MCI imparts significant challenges to any review of this subject. The pathologic substrate of MCI is equally complex and must take into account not only conventional plaque and tangle pathology but also a wide range of cellular biochemical and molecular deficits many of which relate to cognitive decline as well as compensatory responses to the progressive disease process. The multifaceted nature of the neuronal disconnection syndrome associated with MCI, suggests that there is no single event, which precipitates this prodromal stage of AD. In fact, it can be argued that neuronal degeneration initiated at different levels of the central nervous system drive cognitive decline as a final common pathway at this stage of the dementing disease process. PMID:22101321

  3. Mild coal pretreatment to improve liquefaction reactivity

    SciTech Connect

    Miller, R.L.

    1991-01-01

    This report describes work completed during the fifth quarter of a three year project to study the effects of mild chemical pretreatment on coal dissolution reactivity during low severity liquefaction or coal/oil coprocessing. The overall objective of this research is to elucidate changes in the chemical and physical structure of coal by pretreating with methanol or other simple organic solvent and a trace amount of hydrochloric acid and measure the influence of these changes on coal dissolution reactivity. Work this quarter focused on analytical characterization of untreated and treated Wyodak subbituminous coal and Illinois {number sign}6 bituminous coal. Mossbauer spectroscopy and x-ray diffraction techniques were used to study the effect of methanol/HCl pretreatment on the composition of each coal's inorganic phase. Results from these studies indicated that calcite is largely removed during pretreatment, but that other mineral species such as pyrite are unaffected. This finding is significant, since calcite removal appears to directly correlate with low severity liquefaction enhancement. Further work will be performed to study this phenomenon in more detail.

  4. Bacterial phosphating of mild (unalloyed) steel.

    PubMed

    Volkland, H P; Harms, H; Müller, B; Repphun, G; Wanner, O; Zehnder, A J

    2000-10-01

    Mild (unalloyed) steel electrodes were incubated in phosphate-buffered cultures of aerobic, biofilm-forming Rhodococcus sp. strain C125 and Pseudomonas putida mt2. A resulting surface reaction leading to the formation of a corrosion-inhibiting vivianite layer was accompanied by a characteristic electrochemical potential (E) curve. First, E increased slightly due to the interaction of phosphate with the iron oxides covering the steel surface. Subsequently, E decreased rapidly and after 1 day reached -510 mV, the potential of free iron, indicating the removal of the iron oxides. At this point, only scattered patches of bacteria covered the surface. A surface reaction, in which iron was released and vivianite precipitated, started. E remained at -510 mV for about 2 days, during which the vivianite layer grew steadily. Thereafter, E increased markedly to the initial value, and the release of iron stopped. Changes in E and formation of vivianite were results of bacterial activity, with oxygen consumption by the biofilm being the driving force. These findings indicate that biofilms may protect steel surfaces and might be used as an alternative method to combat corrosion.

  5. [Toxicity studies of mild gasification products]. [Quarterly report, October 1, 1992--December 31, 1992

    SciTech Connect

    Not Available

    1992-12-31

    Mild gasification of coal is a technology being developed by the United States Department of Energy and private industry with the hope that a cleaner method of coal use can help meet future energy needs. As the technology develops and its commercial use becomes a more viable possibility, efforts are being made to study the safety or possible toxicity of the mild gasification products. DOE and the National Institute for occupational Safety and Health (NIOSH) are cooperating through an interagency agreement to examine some of these products for their genotoxic potential. NIOSH has studied the mutagenicity of several mild gasification product samples using the Ames Salmonella/microsomal assay. As reported earlier PSIS{number_sign}830331 failed to demonstrate genotoxic activity in the Ames assay under all conditions tested. Since the mild gasification products are complex mixtures, interactions between various components are likely to occur. Such interactions between various components of complex mixtures may increase or decrease genotoxic activity in short-term assays like the Ames test. Although all synergistic interactions may not be detailed, the separate analysis of those components in several classes provides a more accurate view of the genotoxicity of each component and better allows for chemical characterization of the possible mutagens in the mixture. NIOSH has performed mutagenicity studies on the subfractions of PSIS{number_sign}830331. The results of those studies are detailed in this report.

  6. Insights into early treatment of mild asthma: do inhaled corticosteroids make a difference?

    PubMed

    Tan, Wan C

    2007-01-01

    Approaches to the management of moderate-to-severe persistent asthma in both children and adults are widely accepted but the treatment of mild persistent asthma remains controversial because of the lack of agreement on what constitutes mild asthma and whether regular treatment is required at all. Recent evidence indicates that 'mild asthma' may not be as benign a condition as was widely believed and should be treated to improve asthma control and to prevent the significant burden of exacerbation and progression of disease. This is supported by compelling evidence from histologic and clinical studies that have attributed irreversible pathologic and functional airway changes to consequences of persistent airway inflammation and under-treated asthma. This article focuses on the rationale of early treatment of mild persistent asthma, and discusses the various findings from the largest randomized, early-intervention trial with inhaled corticosteroids as regular treatment in patients with asthma of recent onset--the START (inhaled Steroid Treatment As Regular Therapy in early asthma) study. A brief review of the background of the natural history of asthma, the findings from key longitudinal epidemiologic studies on disease progression in children and adults, and the effect of inhaled corticosteroids on this progression are included, to provide further insight into the impact of early treatment on asthma management guidelines.

  7. Sleep deprivation does not affect neuronal susceptibility to mild traumatic brain injury in the rat

    PubMed Central

    Caron, Aimee M; Stephenson, Richard

    2015-01-01

    Mild and moderate traumatic brain injuries (TBIs) (and concussion) occur frequently as a result of falls, automobile accidents, and sporting activities, and are a major cause of acute and chronic disability. Fatigue and excessive sleepiness are associated with increased risk of accidents, but it is unknown whether prior sleep debt also affects the pathophysiological outcome of concussive injury. Using the “dark neuron” (DN) as a marker of reversible neuronal damage, we tested the hypothesis that acute (48 hours) total sleep deprivation (TSD) and chronic sleep restriction (CSR; 10 days, 6-hour sleep/day) affect DN formation following mild TBI in the rat. TSD and CSR were administered using a walking wheel apparatus. Mild TBI was administered under anesthesia using a weight-drop impact model, and the acute neuronal response was observed without recovery. DNs were detected using standard bright-field microscopy with toluidine blue stain following appropriate tissue fixation. DN density was low under home cage and sleep deprivation control conditions (respective median DN densities, 0.14% and 0.22% of neurons), and this was unaffected by TSD alone (0.1%). Mild TBI caused significantly higher DN densities (0.76%), and this was unchanged by preexisting acute or chronic sleep debt (TSD, 0.23%; CSR, 0.7%). Thus, although sleep debt may be predicted to increase the incidence of concussive injury, the present data suggest that sleep debt does not exacerbate the resulting neuronal damage. PMID:26124685

  8. Sleep deprivation does not affect neuronal susceptibility to mild traumatic brain injury in the rat.

    PubMed

    Caron, Aimee M; Stephenson, Richard

    2015-01-01

    Mild and moderate traumatic brain injuries (TBIs) (and concussion) occur frequently as a result of falls, automobile accidents, and sporting activities, and are a major cause of acute and chronic disability. Fatigue and excessive sleepiness are associated with increased risk of accidents, but it is unknown whether prior sleep debt also affects the pathophysiological outcome of concussive injury. Using the "dark neuron" (DN) as a marker of reversible neuronal damage, we tested the hypothesis that acute (48 hours) total sleep deprivation (TSD) and chronic sleep restriction (CSR; 10 days, 6-hour sleep/day) affect DN formation following mild TBI in the rat. TSD and CSR were administered using a walking wheel apparatus. Mild TBI was administered under anesthesia using a weight-drop impact model, and the acute neuronal response was observed without recovery. DNs were detected using standard bright-field microscopy with toluidine blue stain following appropriate tissue fixation. DN density was low under home cage and sleep deprivation control conditions (respective median DN densities, 0.14% and 0.22% of neurons), and this was unaffected by TSD alone (0.1%). Mild TBI caused significantly higher DN densities (0.76%), and this was unchanged by preexisting acute or chronic sleep debt (TSD, 0.23%; CSR, 0.7%). Thus, although sleep debt may be predicted to increase the incidence of concussive injury, the present data suggest that sleep debt does not exacerbate the resulting neuronal damage. PMID:26124685

  9. Radio frequency radiation-induced hyperthermia using Si nanoparticle-based sensitizers for mild cancer therapy.

    PubMed

    Tamarov, Konstantin P; Osminkina, Liubov A; Zinovyev, Sergey V; Maximova, Ksenia A; Kargina, Julia V; Gongalsky, Maxim B; Ryabchikov, Yury; Al-Kattan, Ahmed; Sviridov, Andrey P; Sentis, Marc; Ivanov, Andrey V; Nikiforov, Vladimir N; Kabashin, Andrei V; Timoshenko, Victor Yu

    2014-01-01

    Offering mild, non-invasive and deep cancer therapy modality, radio frequency (RF) radiation-induced hyperthermia lacks for efficient biodegradable RF sensitizers to selectively target cancer cells and thus avoid side effects. Here, we assess crystalline silicon (Si) based nanomaterials as sensitizers for the RF-induced therapy. Using nanoparticles produced by mechanical grinding of porous silicon and ultraclean laser-ablative synthesis, we report efficient RF-induced heating of aqueous suspensions of the nanoparticles to temperatures above 45-50 °C under relatively low nanoparticle concentrations (<1 mg/mL) and RF radiation intensities (1-5 W/cm(2)). For both types of nanoparticles the heating rate was linearly dependent on nanoparticle concentration, while laser-ablated nanoparticles demonstrated a remarkably higher heating rate than porous silicon-based ones for the whole range of the used concentrations from 0.01 to 0.4 mg/mL. The observed effect is explained by the Joule heating due to the generation of electrical currents at the nanoparticle/water interface. Profiting from the nanoparticle-based hyperthermia, we demonstrate an efficient treatment of Lewis lung carcinoma in vivo. Combined with the possibility of involvement of parallel imaging and treatment channels based on unique optical properties of Si-based nanomaterials, the proposed method promises a new landmark in the development of new modalities for mild cancer therapy. PMID:25391603

  10. Radio frequency radiation-induced hyperthermia using Si nanoparticle-based sensitizers for mild cancer therapy.

    PubMed

    Tamarov, Konstantin P; Osminkina, Liubov A; Zinovyev, Sergey V; Maximova, Ksenia A; Kargina, Julia V; Gongalsky, Maxim B; Ryabchikov, Yury; Al-Kattan, Ahmed; Sviridov, Andrey P; Sentis, Marc; Ivanov, Andrey V; Nikiforov, Vladimir N; Kabashin, Andrei V; Timoshenko, Victor Yu

    2014-11-13

    Offering mild, non-invasive and deep cancer therapy modality, radio frequency (RF) radiation-induced hyperthermia lacks for efficient biodegradable RF sensitizers to selectively target cancer cells and thus avoid side effects. Here, we assess crystalline silicon (Si) based nanomaterials as sensitizers for the RF-induced therapy. Using nanoparticles produced by mechanical grinding of porous silicon and ultraclean laser-ablative synthesis, we report efficient RF-induced heating of aqueous suspensions of the nanoparticles to temperatures above 45-50 °C under relatively low nanoparticle concentrations (<1 mg/mL) and RF radiation intensities (1-5 W/cm(2)). For both types of nanoparticles the heating rate was linearly dependent on nanoparticle concentration, while laser-ablated nanoparticles demonstrated a remarkably higher heating rate than porous silicon-based ones for the whole range of the used concentrations from 0.01 to 0.4 mg/mL. The observed effect is explained by the Joule heating due to the generation of electrical currents at the nanoparticle/water interface. Profiting from the nanoparticle-based hyperthermia, we demonstrate an efficient treatment of Lewis lung carcinoma in vivo. Combined with the possibility of involvement of parallel imaging and treatment channels based on unique optical properties of Si-based nanomaterials, the proposed method promises a new landmark in the development of new modalities for mild cancer therapy.

  11. Radio frequency radiation-induced hyperthermia using Si nanoparticle-based sensitizers for mild cancer therapy

    NASA Astrophysics Data System (ADS)

    Tamarov, Konstantin P.; Osminkina, Liubov A.; Zinovyev, Sergey V.; Maximova, Ksenia A.; Kargina, Julia V.; Gongalsky, Maxim B.; Ryabchikov, Yury; Al-Kattan, Ahmed; Sviridov, Andrey P.; Sentis, Marc; Ivanov, Andrey V.; Nikiforov, Vladimir N.; Kabashin, Andrei V.; Timoshenko, Victor Yu

    2014-11-01

    Offering mild, non-invasive and deep cancer therapy modality, radio frequency (RF) radiation-induced hyperthermia lacks for efficient biodegradable RF sensitizers to selectively target cancer cells and thus avoid side effects. Here, we assess crystalline silicon (Si) based nanomaterials as sensitizers for the RF-induced therapy. Using nanoparticles produced by mechanical grinding of porous silicon and ultraclean laser-ablative synthesis, we report efficient RF-induced heating of aqueous suspensions of the nanoparticles to temperatures above 45-50°C under relatively low nanoparticle concentrations (<1 mg/mL) and RF radiation intensities (1-5 W/cm2). For both types of nanoparticles the heating rate was linearly dependent on nanoparticle concentration, while laser-ablated nanoparticles demonstrated a remarkably higher heating rate than porous silicon-based ones for the whole range of the used concentrations from 0.01 to 0.4 mg/mL. The observed effect is explained by the Joule heating due to the generation of electrical currents at the nanoparticle/water interface. Profiting from the nanoparticle-based hyperthermia, we demonstrate an efficient treatment of Lewis lung carcinoma in vivo. Combined with the possibility of involvement of parallel imaging and treatment channels based on unique optical properties of Si-based nanomaterials, the proposed method promises a new landmark in the development of new modalities for mild cancer therapy.

  12. Thermoseparating aqueous two-phase systems: Recent trends and mechanisms.

    PubMed

    Leong, Yoong Kit; Lan, John Chi-Wei; Loh, Hwei-San; Ling, Tau Chuan; Ooi, Chien Wei; Show, Pau Loke

    2016-02-01

    Having the benefits of being environmentally friendly, providing a mild environment for bioseparation, and scalability, aqueous two-phase systems (ATPSs) have increasingly caught the attention of industry and researchers for their application in the isolation and recovery of bioproducts. The limitations of conventional ATPSs give rise to the development of temperature-induced ATPSs that have distinctive thermoseparating properties and easy recyclability. This review starts with a brief introduction to thermoseparating ATPSs, including its history, unique characteristics and advantages, and lastly, key factors that influence partitioning. The underlying mechanism of temperature-induced ATPSs is covered together with a summary of recent applications. Thermoseparating ATPSs have been proven as a solution to the demand for economically favorable and environmentally friendly industrial-scale bioextraction and purification techniques. PMID:26447739

  13. [Medical therapy of osteoporosis in patients with mildly to moderate decreased renal function].

    PubMed

    Eiken, Pia A; Vestergaard, Peter

    2012-11-19

    Both chronic kidney disease and osteoporosis are frequent conditions in the general population. Most drugs for treating osteoporosis seem safe in terms of affecting renal function for patients with mildly to moderate decreased renal function. There are very few data on the efficacy (reduction in fracture risk) or safety in patients with severely decreased renal function (glomerular filtration rate < 30 ml/min) or on dialysis. PMID:23171789

  14. [Extraction of alpha-cypermethrin from aqueous methanol solutions].

    PubMed

    Shormanov, V K; Chigareva, E N; Belousova, O V

    2010-01-01

    Alpha cypermethrin was extracted from aqueous methanol solutions using hydrophobic organic solvents. The efficiency of extraction was shown to depend on the chemical nature of the solvent, the water to methanol ratio, and saturation of the aqueous methanol layer with an electrolyte. Optimal extraction of alpha-cypermethrin was achieved using toluene as the solvent under desalinization conditions. The extraction factor for the removal of the sought amount of alpha-cypermethrin from the water-methanol solution (4:1) using various solvents was calculated.

  15. Electroresponsive aqueous silk protein as "smart" mechanical damping fluid.

    PubMed

    Jose, Rod R; Elia, Roberto; Tien, Lee W; Kaplan, David L

    2014-05-14

    Here we demonstrate the effectiveness of an electroresponsive aqueous silk protein polymer as a smart mechanical damping fluid. The aqueous polymer solution is liquid under ambient conditions, but is reversibly converted into a gel once subjected to an electric current, thereby increasing or decreasing in viscosity. This nontoxic, biodegradable, reversible, edible fluid also bonds to device surfaces and is demonstrated to reduce friction and provide striking wear protection. The friction and mechanical damping coefficients are shown to modulate with electric field exposure time and/or intensity. Damping coefficient can be modulated electrically, and then preserved without continued power for longer time scales than conventional "smart" fluid dampers. PMID:24750065

  16. Removal of phosphate from aqueous solutions by electro-coagulation.

    PubMed

    Bektaş, Nihal; Akbulut, Hilal; Inan, Hatice; Dimoglo, Anatoly

    2004-01-30

    The aim of this paper was to investigate the feasibility of the removal of phosphate from aqueous solution by electro-coagulation (EC). The current density (CD) between 2.5 and 10 mA cm(-2) and duration in the limits of 5-20 min were tried for different concentrations. In order to determine optimal operating conditions, the EC process used for the phosphate removal was examined in dependence with the CD, initial concentrations and time. The results of the experimental batch processing showed high effectiveness of the EC method in removing phosphate from aqueous solutions. PMID:15177098

  17. [Extraction of alpha-cypermethrin from aqueous methanol solutions].

    PubMed

    Shormanov, V K; Chigareva, E N; Belousova, O V

    2010-01-01

    Alpha cypermethrin was extracted from aqueous methanol solutions using hydrophobic organic solvents. The efficiency of extraction was shown to depend on the chemical nature of the solvent, the water to methanol ratio, and saturation of the aqueous methanol layer with an electrolyte. Optimal extraction of alpha-cypermethrin was achieved using toluene as the solvent under desalinization conditions. The extraction factor for the removal of the sought amount of alpha-cypermethrin from the water-methanol solution (4:1) using various solvents was calculated. PMID:20734789

  18. Removal of phosphate from aqueous solutions by electro-coagulation.

    PubMed

    Bektaş, Nihal; Akbulut, Hilal; Inan, Hatice; Dimoglo, Anatoly

    2004-01-30

    The aim of this paper was to investigate the feasibility of the removal of phosphate from aqueous solution by electro-coagulation (EC). The current density (CD) between 2.5 and 10 mA cm(-2) and duration in the limits of 5-20 min were tried for different concentrations. In order to determine optimal operating conditions, the EC process used for the phosphate removal was examined in dependence with the CD, initial concentrations and time. The results of the experimental batch processing showed high effectiveness of the EC method in removing phosphate from aqueous solutions.

  19. Aqueous Alteration of Basalts: Earth, Moon, and Mars

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W.

    2007-01-01

    the aqueous alteration of lunar materials and simulants (e.g., Keller and Huang, 1971; Eick et al., 1996). Lunar basalts are void of water and highly reduced, hence, these materials are initially very reactive when exposed to water under oxidizing conditions.

  20. Polyelectrolyte brushes: a novel stable lubrication system in aqueous conditions.

    PubMed

    Kobayashi, Motoyasu; Terada, Masami; Takahara, Atsushi

    2012-01-01

    Surface-initiated controlled radical copolymerizations of 2-dimethylaminoethyl methacrylate (DMAEMA), 2-(methacryloyloxy)ethyl phosphorylcholine (MPC), 2-(methacryloyloxy)ethyltrimethylammonium chloride) (MTAC), and 3-sulfopropyl methacrylate potassium salt (SPMK) were carried out on a silicon wafer and glass ball to prepare polyelectrolyte brushes with excellent water wettability. The frictional coefficient of the polymer brushes was recorded on a ball-on-plate type tribometer by linear reciprocating motion of the brush specimen at a selected velocity of 1.5 x 10(-3) m s-1 under a normal load of 0.49 N applied to the stationary glass ball (d = 10 mm) at 298 K. The poly(DMAEMA-co-MPC) brush partially cross-linked by bis(2-iodoethoxy)ethane maintained a relatively low friction coefficient around 0.13 under humid air (RH > 75%) even after 200 friction cycles. The poly(SPMK) brush revealed an extremely low friction coefficient around 0.01 even after 450 friction cycles. We supposed that the abrasion of the brush was prevented owing to the good affinity of the poly(SPMK) brush for water forming a water lubrication layer, and electrostatic repulsive interactions among the brushes bearing sulfonic acid groups. Furthermore, the poly(SPMK-co-MTAC) brush with a chemically cross-linked structure showed a stable low friction coefficient in water even after 1400 friction cycles under a normal load of 139 MPa, indicating that the cross-linking structure improved the wear resistance of the brush layer.

  1. Desorption of cesium from granite under various aqueous conditions.

    PubMed

    Wang, Tsing-Hai; Li, Ming-Hsu; Wei, Yuan-Yaw; Teng, Shi-Ping

    2010-12-01

    In this work the desorption of cesium ions from crushed granite in synthetic groundwater (GW) and seawater (SW) was investigated. Results were compared with those obtained in deionized water (DW) and in two kinds of extraction solutions, namely: MgCl(2) and NaOAc (sodium acetate). In general, the desorption rate of Cs from crushed granite increased proportionally with initial Cs loadings. Also, amounts of desorbed Cs ions followed the tendency in the order SW>GW>NaOAc approximately equal MgCl(2)>DW solutions. This indicated that the utilization of extraction reagents for ion exchange will underestimate the Cs desorption behavior. Fitting these experimental data by Langmuir model showed that these extraction reagents have reduced Cs uptake by more than 90%, while only less than 1% of adsorbed Cs ions are still observed in GW and SW solutions in comparison to those in DW. Further SEM/EDS mapping studies clearly demonstrate that these remaining adsorbed Cs ions are at the fracture areas of biotite.

  2. Polyelectrolyte brushes: a novel stable lubrication system in aqueous conditions.

    PubMed

    Kobayashi, Motoyasu; Terada, Masami; Takahara, Atsushi

    2012-01-01

    Surface-initiated controlled radical copolymerizations of 2-dimethylaminoethyl methacrylate (DMAEMA), 2-(methacryloyloxy)ethyl phosphorylcholine (MPC), 2-(methacryloyloxy)ethyltrimethylammonium chloride) (MTAC), and 3-sulfopropyl methacrylate potassium salt (SPMK) were carried out on a silicon wafer and glass ball to prepare polyelectrolyte brushes with excellent water wettability. The frictional coefficient of the polymer brushes was recorded on a ball-on-plate type tribometer by linear reciprocating motion of the brush specimen at a selected velocity of 1.5 x 10(-3) m s-1 under a normal load of 0.49 N applied to the stationary glass ball (d = 10 mm) at 298 K. The poly(DMAEMA-co-MPC) brush partially cross-linked by bis(2-iodoethoxy)ethane maintained a relatively low friction coefficient around 0.13 under humid air (RH > 75%) even after 200 friction cycles. The poly(SPMK) brush revealed an extremely low friction coefficient around 0.01 even after 450 friction cycles. We supposed that the abrasion of the brush was prevented owing to the good affinity of the poly(SPMK) brush for water forming a water lubrication layer, and electrostatic repulsive interactions among the brushes bearing sulfonic acid groups. Furthermore, the poly(SPMK-co-MTAC) brush with a chemically cross-linked structure showed a stable low friction coefficient in water even after 1400 friction cycles under a normal load of 139 MPa, indicating that the cross-linking structure improved the wear resistance of the brush layer. PMID:23285641

  3. Nutritional condition of Northern Yellowstone Elk

    USGS Publications Warehouse

    Cook, R.C.; Cook, J.G.; Mech, L.D.

    2004-01-01

    Ultrasonography and body condition scoring was used to estimate nutritional condition of northern Yellowstone elk in late winter. Probability of pregnancy was related to body fat, and lactating cows had 50% less fat than non-lactating cows. For mild to normal winters, most of the elk were in good condition.

  4. A Study on the Aqueous Formation of Secondary Organic Aerosols

    NASA Astrophysics Data System (ADS)

    Sinclair, K.; Tsigaridis, K.

    2013-12-01

    The effect aerosols have on radiative forcing in the atmosphere is recognized as one of the largest uncertainties in the radiation budget. About 80% of organic aerosol mass in the atmosphere is estimated to be created though secondary processes. Recently, the aqueous formation of secondary organic aerosols (SOA) has become recognized as important when considering the source, transformation and radiative impacts of SOA. This work focuses on implementing a mechanism for aqueous SOA formation that can be used in atmospheric chemistry and models of all scales, from box to global. A box model containing a simplified chemical mechanism for the aqueous production of precursors of aqueous SOA (Myriokefalitakis et al. (2011) is coupled to gas-phase chemistry which uses the carbon bond mechanism (CBM) IV is presented. The model implements aqueous chemistry of soluble gases, both in-cloud and aerosol water, including organic compounds such as glyoxal and methylglyoxal, which have been shown as potentially significant sources for dissolved secondary organic aerosols. This mechanism implements aqueous phase mass transfer and molecular dissociation. The model's performance is evaluated against previous box model studies from the literature. A comparison is conducted between the detailed GAMMA model (McNeill et al., 2012), which is constrained with chamber experiments and the one developed here. The model output under different atmospheric conditions is explored and differences and sensitivities are assessed. The objective of this work is to create a robust framework for simulating aqueous phase formation of SOA and maximizing the computational efficiency of the model, while maintaining accuracy, in order to later use the exact mechanism in global climate simulations.

  5. Aqueous Alteration on Mars: Evidence from Landed Missions

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W.; Morris, Richard V.; Clark, Benton C., III; Yen, Albert S.; Gellert, Ralf

    2015-01-01

    Mineralogical and geochemical data returned by orbiters and landers over the past 15 years have substantially enhanced our understanding of the history of aqueous alteration on Mars. Here, we summarize aqueous processes that have been implied from data collected by landed missions. Mars is a basaltic planet. The geochemistry of most materials has not been “extensively” altered by open-system aqueous processes and have average Mars crustal compositions. There are few examples of open-system alteration, such as Gale crater’s Pahrump Hills mudstone. Types of aqueous alteration include (1) acid-sulfate and (2) hydrolytic (circum-neutral/alkaline pH) with varying water-to-rock ratios. Several hypotheses have been suggested for acid-sulfate alteration including (1) oxidative weathering of ultramafic igneous rocks containing sulfides; (2) sulfuric acid weathering of basaltic materials; (3) acid fog weathering of basaltic materials; and (4) near-neutral pH subsurface solutions rich in Fe (sup 2 plus) that rapidly oxidized to Fe (sup 3 plus) producing excess acidity. Meridiani Planum’s sulfate-rich sedimentary deposit containing jarosite is the most “famous” acid-sulfate environment visited on Mars, although ferric sulfate-rich soils are common in Gusev crater’s Columbia Hills and jarosite was recently discovered in the Pahrump Hills. An example of aqueous alteration under circum-neutral pH conditions is the formation of Fe-saponite with magnetite in situ via aqueous alteration of olivine in Gale crater’s Sheepbed mudstone. Circum-neutral pH, hydrothermal conditions were likely required for the formation of Mg-Fe carbonate in the Columbia Hills. Diagenetic features (e.g., spherules, fracture filled veins) indicate multiple episodes of aqueous alteration/diagenesis in most sedimentary deposits. However, low water-to-rock ratios are prominent at most sites visited by landed missions (e.g., limited water for reaction to form crystalline phases possibly

  6. Aqueous Corrosion Rates for Waste Package Materials

    SciTech Connect

    S. Arthur

    2004-10-08

    The purpose of this analysis, as directed by ''Technical Work Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]), is to compile applicable corrosion data from the literature (journal articles, engineering documents, materials handbooks, or standards, and national laboratory reports), evaluate the quality of these data, and use these to perform statistical analyses and distributions for aqueous corrosion rates of waste package materials. The purpose of this report is not to describe the performance of engineered barriers for the TSPA-LA. Instead, the analysis provides simple statistics on aqueous corrosion rates of steels and alloys. These rates are limited by various aqueous parameters such as temperature (up to 100 C), water type (i.e., fresh versus saline), and pH. Corrosion data of materials at pH extremes (below 4 and above 9) are not included in this analysis, as materials commonly display different corrosion behaviors under these conditions. The exception is highly corrosion-resistant materials (Inconel Alloys) for which rate data from corrosion tests at a pH of approximately 3 were included. The waste package materials investigated are those from the long and short 5-DHLW waste packages, 2-MCO/2-DHLW waste package, and the 21-PWR commercial waste package. This analysis also contains rate data for some of the materials present inside the fuel canisters for the following fuel types: U-Mo (Fermi U-10%Mo), MOX (FFTF), Thorium Carbide and Th/U Carbide (Fort Saint Vrain [FSVR]), Th/U Oxide (Shippingport LWBR), U-metal (N Reactor), Intact U-Oxide (Shippingport PWR, Commercial), aluminum-based, and U-Zr-H (TRIGA). Analysis of corrosion rates for Alloy 22, spent nuclear fuel, defense high level waste (DHLW) glass, and Titanium Grade 7 can be found in other analysis or model reports.

  7. Converting sugars to sugar alcohols by aqueous phase catalytic hydrogenation

    DOEpatents

    Elliott, Douglas C.; Werpy, Todd A.; Wang, Yong; Frye, Jr., John G.

    2003-05-27

    The present invention provides a method of converting sugars to their corresponding sugar alcohols by catalytic hydrogenation in the aqueous phase. It has been found that surprisingly superior results can be obtained by utilizing a relatively low temperature (less than 120.degree. C.), selected hydrogenation conditions, and a hydrothermally stable catalyst. These results include excellent sugar conversion to the desired sugar alcohol, in combination with long life under hydrothermal conditions.

  8. Remission of Cognitive Deficits in Parkinson's Disease: Recovery from a Nonamnestic Mild Cognitive Impairment or Psychiatric Symptoms Remission?

    PubMed Central

    de Paula, Jonas Jardim; Cintra, Marco Túlio Gualberto; Miranda, Débora Marques; Bicalho, Maria Aparecida Camargos; Moares, Edgar Nunes; Malloy-Diniz, Leandro Fernandes

    2012-01-01

    Mild cognitive impairment is a clinical condition more frequent in patients with Parkinson's disease than in general population. The nonamnestic presentations, usually characterized by executive dysfunction, are most prevalent. We present a case report of a Parkinson's disease patient diagnosed with nonamnestic mild cognitive impairment that showed complete remission of cognitive symptoms after one year. We discuss the possible causes for the remission, focusing on the treatment of medical conditions such as a major depressive episode and vitamin B12 deficiency, in addition to the change of pharmacological treatment. In a third assessment, cognitive performance remained normal. The case report highlights the importance of controlling clinical comorbidities on the assessment and followup of mild cognitive impairment, especially on Parkinson's disease. PMID:23193494

  9. NMR Studies on the Aqueous Phase Photochemical Degradation of TNT

    SciTech Connect

    Thorn, Kevin A.; Cox, Larry G.

    2008-04-06

    Aqueous phase photochemical degradation of 2,4,6-trinitrotoluene (TNT) is an important pathway in several environments, including washout lagoon soils, impact craters from partially detonated munitions that fill with rain or groundwater, and shallow marine environments containing unexploded munitions that have corroded. Knowledge of the degradation products is necessary for compliance issues on military firing ranges and formerly used defense sites. Previous laboratory studies have indicated that UV irradiation of aqueous TNT solutions results in a multicomponent product mixture, including polymerization compounds, that has been only partially resolved by mass spectrometric analyses. This study illustrates how a combination of solid and liquid state 1H, 13C, and 15N NMR spectroscopy, including two dimensional analyses, provides complementary information on the total product mixture from aqueous photolysis of TNT, and the effect of reaction conditions. Among the degradation products detected were amine, amide, azoxy, azo, and carboxylic acid compounds.

  10. Aqueous-phase source of formic acid in clouds

    NASA Technical Reports Server (NTRS)

    Chameides, W. L.; Davis, D. D.

    1983-01-01

    The coupled gas- and aqueous-phase cloud chemistry of HCOOH were examined for controlling factors in the acidity of cloud and rainwater. Attention was given to the aqueous OH/HO2 system that yields an OH species that is highly reactive with other species, notably SO2 and the formaldehyde/formic acid complex. A numerical model was developed to simulate the cloud chemistry in the remote troposphere, with considerations given to CH4-CO-NO(x)-O3-H(x)O(y) system. It was determined that aqueous phase OH radicals can produce and destroy formic acid droplets in daylight conditions, as well as control formic acid levels in rainwater. It is sugested that the same types of reactions may be involved in the control of acetic acid and other organic acids.

  11. Sleep Habits in Mild Cognitive Impairment

    PubMed Central

    Hayes, Tamara L.; Riley, Thomas; Mattek, Nora; Pavel, Misha; Kaye, Jeffrey A.

    2013-01-01

    We explored the relationship between sleep disturbances and mild cognitive impairment (MCI) in community-dwelling seniors. Recent evidence suggests that sleep habits are differentially compromised in different subtypes of MCI, but the relationship between sleep disruption and MCI remains poorly understood. We gathered daily objective measures of sleep disturbance from 45 seniors, including 16 with MCI (mean age 86.9 ± 4.3 years), over a six month period. We also collected self-report measures of sleep disturbance. Although there were no differences between groups in any of our self-report measures, we found that amnestic MCI (aMCI) volunteers had less disturbed sleep than both non-amnestic MCI (naMCI) and cognitively intact volunteers, as measured objectively by movement in bed at night (F2,1078=4.30, p=0.05), wake after sleep onset (F2,1078=41.6, p<0.001), and times up at night (F2,1078=26.7, p<0.001). The groups did not differ in total sleep time. In addition, the aMCI group had less day-to-day variability in these measures than the intact and naMCI volunteers. In general, the naMCI volunteers showed a level of disturbed sleep that was intermediate to that of aMCI and intact volunteers. These differences in sleep disruption between aMCI and naMCI may be related to differences in the pathology underlying these MCI subtypes. PMID:24145694

  12. DEVELOPMENT OF A CO2 SEQUESTRATION MODULE BY INTEGRATING MINERAL ACTIVATION AND AQUEOUS CARBONATION

    SciTech Connect

    M. Mercedes Maroto-Valer; John M. Andresen; George Alexander

    2004-11-15

    Mineral carbonation is a promising concept for permanent CO{sub 2} sequestration due to the vast natural abundance of the raw minerals, the permanent storage of CO{sub 2} in solid form as carbonates, and the overall reaction being exothermic. However, the primary drawback to mineral carbonation is the reaction kinetics. To accelerate the reaction, aqueous carbonation processes are preferred, where the minerals are firstly dissolved in solution. In aqueous carbonation, the key step is the dissolution rate of the mineral, where the mineral dissolution reaction is likely to be surface controlled. In order to accelerate the dissolution process, the serpentine can be ground to very fine particle size (<37 {micro}m), but this is a very energy intensive process. Alternatively, magnesium could be chemically extracted in aqueous solution. Phase I showed that chemical surface activation helps to dissolve the magnesium from the serpentine minerals (particle size {approx}100 {micro}m), and furthermore, the carbonation reaction can be conducted under mild conditions (20 C and 650 psig) compared to previous studies that required >185 C, >1850 psig and <37 {micro}m particle size. Phase I also showed that over 70% of the magnesium can be extracted at ambient temperature leaving amorphous SiO{sub 2} with surface areas {approx} 330m{sup 2}/g. The overall objective of Phase 2 of this research program is to optimize the active carbonation process developed in Phase I in order to design an integrated CO{sub 2} sequestration module. During the current reporting period, Task 1 ''Mineral activation'' was initiated and focused on a parametric study to optimize the operation conditions for the mineral activation, where serpentine and sulfuric acid were reacted, as following the results from Phase 1. Several experimental factors were outlined as having a potential influence on the mineral activation. This study has focused to date on the effects of varying the acid concentration, particle

  13. Germanium: An aqueous processing review

    SciTech Connect

    Lier, R.J.M. van; Dreisinger, D.B.

    1995-08-01

    In industrial aqueous solutions, germanium generally occurs in trace amounts amid high concentrations of other metals, such as zinc, copper and iron. Separation of germanium from these metals as well as its isolation from gallium and indium pose a real challenge to the hydrometallurgist. After a brief discussion of the aqueous chemistry of germanium, this paper reviews the flowsheet of the Apex Mine in Utah. The Apex property was the only mine in the world to be operated primarily for production of gallium and germanium, but apparently closed due to great operating difficulties. Several process variants proposed for the treatment of the Apex ore, including bioleaching methods, are addressed. Following a more general description of the behavior of germanium in hydrometallurgical zinc processing streams, available technology for its recovery from aqueous solutions is summarized. Precipitation, solvent extraction, ion exchange, electrowinning, ion flotation and liquid-membrane separation are all outlined in terms of the aqueous chemistry of germanium. Finally, the production of high purity germanium dioxide and metal is briefly discussed. 61 refs.

  14. Aqueous Processing Material Accountability Instrumentation

    SciTech Connect

    Robert Bean

    2007-09-01

    Increased use of nuclear power will require new facilities. The U.S. has not built a new spent nuclear fuel reprocessing facility for decades. Reprocessing facilities must maintain accountability of their nuclear fuel. This survey report on the techniques used in current aqueous reprocessing facilities, and provides references to source materials to assist facility design efforts.

  15. CESIUM RECOVERY FROM AQUEOUS SOLUTIONS

    DOEpatents

    Goodall, C.A.

    1960-09-13

    A process is given for precipitating cesium on zinc ferricyanide (at least 0.0004 M) from aqueous solutions containing mineral acid in a concentration of from 0.2 N acidity to 0.61 N acid-deficiency and advantageously, but not necessarily, also aluminum nitrate in a concentration of from l to 2.5 M.

  16. Aqueous-Spray Cleaning System

    NASA Technical Reports Server (NTRS)

    Morgan, Gene E.; Hoult, William S.; Simpson, Gareth L.

    1996-01-01

    Simple aqueous-spray cleaning system with overall dimensions comparable to large kitchen refrigerator constructed for use in cleaning hardware in shop. Made of commercially available parts and materials. Incorporates economical cleaner-and-rinse-recycling subsystem, as well as programmable logic-controller device for either manual or automatic operation.

  17. The ultrasound-assisted aqueous extraction of rice bran oil.

    PubMed

    Khoei, Maryam; Chekin, Fereshteh

    2016-03-01

    In this work, aqueous extraction of rice bran oil was done without and with ultrasound pretreatment. Key factors controlling the extraction and optimal operating conditions were identified. The highest extraction efficiency was found at pH=12, temperature of 45°C, agitation speed of 800rpm and agitation time of 15min, ultrasound treatment time of 70min and ultrasound treatment temperature of 25°C. Moreover, extraction yields were compared to ultrasound-assisted aqueous extraction and Soxhlet extraction. The results showed that the yield of rice bran oil at ultrasound-assisted aqueous extraction was close to the yield of oil extracted by hexane Soxhlet extraction. This result implied that the yield of rice bran oil was significantly influenced by ultrasound. With regard to quality, the oil extracted by ultrasound-assisted aqueous process had a lower content of free fatty acid and lower color imparting components than the hexane-extracted oil. Also, effect of parboiling of paddy on hexane and ultrasound-assisted aqueous extraction was studied. Both extraction methods gives higher percentage of oil from par boiled rice bran compared with raw rice bran. This may be due to the fact that parboiling releases the oil.

  18. The ultrasound-assisted aqueous extraction of rice bran oil.

    PubMed

    Khoei, Maryam; Chekin, Fereshteh

    2016-03-01

    In this work, aqueous extraction of rice bran oil was done without and with ultrasound pretreatment. Key factors controlling the extraction and optimal operating conditions were identified. The highest extraction efficiency was found at pH=12, temperature of 45°C, agitation speed of 800rpm and agitation time of 15min, ultrasound treatment time of 70min and ultrasound treatment temperature of 25°C. Moreover, extraction yields were compared to ultrasound-assisted aqueous extraction and Soxhlet extraction. The results showed that the yield of rice bran oil at ultrasound-assisted aqueous extraction was close to the yield of oil extracted by hexane Soxhlet extraction. This result implied that the yield of rice bran oil was significantly influenced by ultrasound. With regard to quality, the oil extracted by ultrasound-assisted aqueous process had a lower content of free fatty acid and lower color imparting components than the hexane-extracted oil. Also, effect of parboiling of paddy on hexane and ultrasound-assisted aqueous extraction was studied. Both extraction methods gives higher percentage of oil from par boiled rice bran compared with raw rice bran. This may be due to the fact that parboiling releases the oil. PMID:26471585

  19. Modeling a set of heavy oil aqueous pyrolysis experiments

    SciTech Connect

    Thorsness, C.B.; Reynolds, J.G.

    1996-11-01

    Aqueous pyrolysis experiments, aimed at mild upgrading of heavy oil, were analyzed using various computer models. The primary focus of the analysis was the pressure history of the closed autoclave reactors obtained during the heating of the autoclave to desired reaction temperatures. The models used included a means of estimating nonideal behavior of primary components with regard to vapor liquid equilibrium. The modeling indicated that to match measured autoclave pressures, which often were well below the vapor pressure of water at a given temperature, it was necessary to incorporate water solubility in the oil phase and an activity model for the water in the oil phase which reduced its fugacity below that of pure water. Analysis also indicated that the mild to moderate upgrading of the oil which occurred in experiments that reached 400{degrees}C or more using a FE(III) 2-ethylhexanoate could be reasonably well characterized by a simple first order rate constant of 1.7xl0{sup 8} exp(-20000/T)s{sup {minus}l}. Both gas production and API gravity increase were characterized by this rate constant. Models were able to match the complete pressure history of the autoclave experiments fairly well with relatively simple equilibria models. However, a consistent lower than measured buildup in pressure at peak temperatures was noted in the model calculations. This phenomena was tentatively attributed to an increase in the amount of water entering the vapor phase caused by a change in its activity in the oil phase.

  20. Antiarthritic effect of aqueous and ethanolic leaf extracts of Pistia stratiotes in adjuvant-induced arthritis in Sprague-Dawley rats

    PubMed Central

    Kyei, Samuel; Koffuor, George A; Boampong, Johnson N

    2012-01-01

    Background Pistia stratiotes has been used effectively to treat a number of inflammatory conditions. This study aims to determine the antiarthritic effect of aqueous and ethanolic leaf extracts of P. stratiotes. Methods Arthritis was induced in Sprague-Dawley rats, paw swelling was measured, and arthritis indices were estimated in rats treated with aqueous and ethanolic leaf extracts of P. stratiotes (AQ PSE and ET PSE, respectively), methotrexate, diclofenac, dexamethasone, and normal saline-treated rats. Radiologic imaging, hematological assessment of red and white blood cells, C-reactive protein and erythrocyte sedimentation rate, as well as histopathological studies were also done. The data were analyzed using GraphPad Prism 5. Results The 30, 100, and 300 mg/kg doses of AQ PSE and the 30 and 100 mg/kg doses of ET PSE caused a significant (P ≤ 0.05–0.001) reduction in ipsilateral paw swelling, similar to the effects of methotrexate, dexamethasone, and diclofenac. Only the 30 mg/kg dose of AQ PSE caused a significant (P ≤ 0.01) reduction in contralateral paw swelling. Arthritic indices reduced significantly (P ≤ 0.05–0.001) at all drug doses, except for the 100 and 300 mg/kg doses of ET PSE. White blood cell levels decreased significantly (P ≤ 0.05–0.01) in arthritic rats treated with the 30 mg/kg dose of AQ PSE and those treated with methotrexate. Erythrocyte sedimentation rate and C-reactive protein levels were significantly (P ≤ 0.01–0.001) lower in all the treatment groups except for the rats treated with AQ PSE 300 mg/kg and ET PSE 100 and 300 mg/kg doses. The arthritic animals treated with 30 mg/kg of the aqueous extract showed no inflammatory changes in the ipsilateral paw, while the contralateral paw showed only foci of mild chronic inflammatory changes, as seen with the reference drug treatment in histopathological studies. Conclusion This study establishes that aqueous and ethanolic extracts of P. stratiotes have antiarthritic

  1. Dual Tasking for the Differentiation between Depression and Mild Cognitive Impairment

    PubMed Central

    Metzger, Florian G.; Hobert, Markus A.; Ehlis, Ann-Christine; Hasmann, Sandra E.; Hahn, Tim; Eschweiler, Gerhard W.; Berg, Daniela; Fallgatter, Andreas J.; Maetzler, Walter

    2016-01-01

    Differentiation of mild cognitive impairment from depression in elderly adults is a clinically relevant issue which is not sufficiently solved. Gait and dual task (DT) parameters may have the potential to complement current diagnostic work-up, as both dementia and depression are associated with changes of gait and DT parameters. Methods: Seven hundred and four participants of the TREND study (Tübinger evaluation of Risk factors for Early detection of NeuroDegeneration) aged 50–80 years were assessed using the Consortium to Establish a Registry for Alzheimer's Disease Plus test battery for testing cognition and Beck's Depression Inventory for evaluation of depression. Based on these results, four groups were defined: acute depressed (N = 53), cognitively mildly impaired (N = 97), acute depressed, and cognitively mildly impaired (N = 15), and controls (N = 536). Participants underwent a 20 m walk and checking boxes task under single (ST) and DT conditions. ST and DT performance and dual task costs (DTC) were calculated. Due to the typical age of increasing incidence of depressive and also cognitive symptoms, the 7th decade was calculated separately. Results: ST speeds of gait and checking boxes, DT walking speed, and walking DTC were significantly different between groups. Healthy controls were the fastest in all paradigms and cognitively mildly impaired had higher DTC than depressed individuals. Additionally, we constructed a multivariate predictive model differentiating the groups on a single-subject level. Conclusion: DT parameters are simply and comfortably measureable, and DTC can easily be determined. The combination of these parameters allows a differentiation of depressed and cognitively mildly impaired elderly adults. PMID:27790136

  2. Characterizing Fullerene Nanoparticles in Aqueous Suspensions

    EPA Science Inventory

    Studies have indicated that fullerenes can form stable colloidal suspensions in water when introduced to the aqueous phase through solvent exchange, sonication, or extended mixing. The colloidal suspensions created using these techniques have effective aqueous phase concentratio...

  3. Models of globular proteins in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Wentzel, Nathaniel James

    Protein crystallization is a continuing area of research. Currently, there is no universal theory for the conditions required to crystallize proteins. A better understanding of protein crystallization will be helpful in determining protein structure and preventing and treating certain diseases. In this thesis, we will extend the understanding of globular proteins in aqueous solutions by analyzing various models for protein interactions. Experiments have shown that the liquid-liquid phase separation curves for lysozyme in solution with salt depend on salt type and salt concentration. We analyze a simple square well model for this system whose well depth depends on salt type and salt concentration, to determine the phase coexistence surfaces from experimental data. The surfaces, calculated from a single Monte Carlo simulation and a simple scaling argument, are shown as a function of temperature, salt concentration and protein concentration for two typical salts. Urate Oxidase from Asperigillus flavus is a protein used for studying the effects of polymers on the crystallization of large proteins. Experiments have determined some aspects of the phase diagram. We use Monte Carlo techniques and perturbation theory to predict the phase diagram for a model of urate oxidase in solution with PEG. The model used includes an electrostatic interaction, van der Waals attraction, and a polymerinduced depletion interaction. The results agree quantitatively with experiments. Anisotropy plays a role in globular protein interactions, including the formation of hemoglobin fibers in sickle cell disease. Also, the solvent conditions have been shown to play a strong role in the phase behavior of some aqueous protein solutions. Each has previously been treated separately in theoretical studies. Here we propose and analyze a simple, combined model that treats both anisotropy and solvent effects. We find that this model qualitatively explains some phase behavior, including the existence of

  4. Neurobehavioral aspects of postconcussive symptoms after mild head injury.

    PubMed

    Bohnen, N; Jolles, J

    1992-11-01

    The sequelae of severe closed head injury have received much attention in the literature, but the effects of mild closed head injury (MHI) are less well established. There is a subgroup of patients who complain of persisting postconcussive symptoms (PCS) beyond the first weeks of recovery. Although the symptoms generally develop in the absence of clear neurological abnormalities, the condition of PCS can be chronic and disabling. It has been assumed that PCS result from an interaction between organic and psychological factors. Differentiating between the effect of primary neurological injury and secondary psychosocial problems is often difficult for clinicians and engenders controversy. Neuropsychological, neurophysiological, and neuroimaging measures can be helpful in selecting patients at risk of developing PCS. Assessment of the level of cognitive functioning, individual susceptibility to stress, and environmental demands may be beneficial in treating symptomatic patients. It is true that the vague and aspecific nature of the postconcussion syndrome may have given rise to the controversy over this entity, but the many methodological inconsistencies in the experimental approaches to the syndrome have certainly enhanced the confusion about this issue. The ensuing controversy surrounding research on the outcome of MHI and the postconcussion syndrome reflects ambiguities in definition, inconsistencies in criteria for patient selection, variation in procedures for neurobehavioral assessment, and difficulty in obtaining follow-up data. PMID:1431820

  5. Mild Metal-Free Hydrosilylation of Secondary Amides to Amines.

    PubMed

    Huang, Pei-Qiang; Lang, Qi-Wei; Wang, Yan-Rong

    2016-05-20

    The combination of amide activation by Tf2O with B(C6F5)3-catalyzed hydrosilylation with TMDS constitutes a method for the one-pot reduction of secondary amides to amines under mild conditions. The method displays a broad applicability for the reduction of many types of substrates, and shows good compatibility and excellent chemoselectivity for many sensitive functional groups. Reductions of a multifunctionalized α,β-unsaturated amide obtained from another synthetic methodology, and a C-H functionalization product produced the corresponding amines in good to excellent yield. Chemoselective reduction of enantiomeric pure (ee >99%) tetrahydro-5-oxo-2-furaneamides yielded 5-(aminomethyl)dihydrofuran-2(3H)-ones in a racemization-free manner. The latter were converted in one pot to N-protected 5-hydroxypiperidin-2-ones, which are building blocks for the synthesis of many natural products. Further elaboration of an intermediate led to a concise four-step synthesis of (-)-epi-pseudoconhydrine. PMID:27100232

  6. Mild cognitive impairment: Conceptual, assessment, ethical, and social issues

    PubMed Central

    Werner, Perla; Korczyn, Amos D

    2008-01-01

    Mild cognitive impairment (MCI) is defined as a condition characterized by newly acquired cognitive decline to an extent that is beyond that expected for age or educational background, yet not causing significant functional impairment. The concept of MCI has received considerable attention in the literature over the past few years, and aspects related to its definition, prevalence, and evolution have been extensively studied and reviewed. Here we attempt to synthesize the implications of the current status of this entity, focusing on the conceptual, methodological, and, in particular, the social and ethical aspects of MCI which have attracted less attention. We discuss the weaknesses of the concept of MCI, which is heterogeneous in etiology, manifestations, and outcomes, and suggest that the emergence of the syndrome at this stage reflects industrial interests related to possible development of drugs for this disorder. On the other hand, the formal diagnosis of MCI, with its implications that the person may develop dementia, may have a grave impact on the psychological state of the individual, at a stage when prediction of outcome is tenuous and possibilities of useful interventions are meager. We present suggestions for the direction of future research in these areas. PMID:18982912

  7. Mild cognitive impairment and its management in older people

    PubMed Central

    Eshkoor, Sima Ataollahi; Hamid, Tengku Aizan; Mun, Chan Yoke; Ng, Chee Kyun

    2015-01-01

    Mild cognitive impairment (MCI) is a common condition in the elderly. It is characterized by deterioration of memory, attention, and cognitive function that is beyond what is expected based on age and educational level. MCI does not interfere significantly with individuals’ daily activities. It can act as a transitional level of evolving dementia with a range of conversion of 10%–15% per year. Thus, it is crucial to protect older people against MCI and developing dementia. The preventive interventions and appropriate treatments should improve cognitive performance, and retard or prevent progressive deficits. The avoidance of toxins, reduction of stress, prevention of somatic diseases, implementation of mental and physical exercises, as well as the use of dietary compounds like antioxidants and supplements can be protective against MCI. The modification of risk factors such as stopping smoking, as well as the treatment of deficiency in vitamins and hormones by correcting behaviors and lifestyle, can prevent cognitive decline in the elderly. The progressive increase in the growth rate of the elderly population can enhance the rate of MCI all over the world. There is no exact cure for MCI and dementia; therefore, further studies are needed in the future to determine causes of MCI and risk factors of progression from MCI to dementia. This will help to find better ways for prevention and treatment of cognitive impairment worldwide. PMID:25914527

  8. Exceptionally cold and mild winters in Europe (1951-2010)

    NASA Astrophysics Data System (ADS)

    Twardosz, Robert; Kossowska-Cezak, Urszula

    2016-07-01

    Extreme thermal conditions appear to occupy an important place among research subjects at a time of climate warming. This study investigates the frequency, duration and spatial extent of thermally anomalous winters in Europe during the 60 years between 1951 and 2010. Exceptionally cold winters (ECWs) and exceptionally mild winters (EMWs) were identified using the statistical criterion of plus/minus two standard deviations from the long-term winter temperature (January-December) recorded at 60 weather stations. It was demonstrated that ECWs have occurred more frequently and covered larger territories than EMWs and that they may occur anywhere in Europe, while EMWs were limited to its southern and western parts. ECWs are characterised by greater absolute temperature anomalies, as anomalies greater than |6.0 °C| account for 35 % of ECWs, but only for 8 % of EMWs. The greatest anomalies are found in the east of the continent. The largest territory affected by an ECW included 24 stations in 1962/1963, while the equivalent among the EMWs included 11 stations in 2006/2007. The study also confirmed an expected trend whereby ECWs diminished in frequency in favour of EMWs in the second half of the 60-year study period.

  9. Aqueous alteration of the Nakhla meteorite

    SciTech Connect

    Gooding, J.L.; Zolensky, M.E.; Wentworth, S.J. Lockheed Engineering and Sciences Co., Houston, TX )

    1991-06-01

    Interior samples of three different Nakhla specimens contain an iron-rich silicate 'rust' (which includes a tentatively identified smectite), Ca-carbonate (probably calcite), Ca-sulfate (possibly gypsum or bassanite), Mg-sulfate (possibly epsomite or kieserite), and NaCl (halite); the total abundance of these phases is estimated as less than 0.01 weight percent of the bulk meteorite. Rust veins are truncated and decrepitated by fusion crust and are preserved as faulted segments in partially healed olivine crystals, indicating that the rust is preterrestrial in origin. Because Ca-carbonate and Ca-sulfate are intergrown with the rust, they are also indicated to be of preterrestrial origin. Similar textural evidence regarding origins of the NaCl and Mg-sulfate is lacking. Impure and poorly crystallized sulfates and halides on the fusion crust of the meteorite suggest leaching of interior (preterrestrial) salts from the interior after Makhla arrived on earth, but coincidental addition of these same salts by terrestrial contamination cannot be exluded. At least the clay-like silicate 'rust', Ca-carbonate, and Ca-sulfate were formed by precipitation from water-based solutions on the Nakhla parent planet, although temperature and pressure conditions of aqueous precipitation are unconstrained by currently available data. It is possible that aqueous alteration on the parent body was responsible for the previously observed disturbance of the Rb-Sr geochronometer in Nakhla at or near 1.3 Ga. 21 refs.

  10. Corrosion problems with aqueous coolants, final report

    SciTech Connect

    Diegle, R B; Beavers, J A; Clifford, J E

    1980-04-11

    The results of a one year program to characterize corrosion of solar collector alloys in aqueous heat-transfer media are summarized. The program involved a literature review and a laboratory investigation of corrosion in uninhibited solutions. It consisted of three separate tasks, as follows: review of the state-of-the-art of solar collector corrosion processes; study of corrosion in multimetallic systems; and determination of interaction between different waters and chemical antifreeze additives. Task 1 involved a comprehensive review of published literature concerning corrosion under solar collector operating conditions. The reivew also incorporated data from related technologies, specifically, from research performed on automotive cooling systems, cooling towers, and heat exchangers. Task 2 consisted of determining the corrosion behavior of candidate alloys of construction for solar collectors in different types of aqueous coolants containing various concentrations of corrosive ionic species. Task 3 involved measuring the degradation rates of glycol-based heat-transfer media, and also evaluating the effects of degradation on the corrosion behavior of metallic collector materials.

  11. Halogen production from aqueous tropospheric particles.

    PubMed

    Herrmann, H; Majdik, Z; Ervens, B; Weise, D

    2003-07-01

    Box model studies have been performed to study the role of aqueous phase chemistry with regard to halogen activation for marine and urban clouds and the marine aerosol as well. Different chemical pathways leading to halogen activation in diluted cloud droplets and highly concentrated sea salt aerosol particles are investigated. The concentration of halides in cloud droplets is significantly smaller than in sea-salt particles, and hence different reaction sequences control the overall chemical conversions. In diluted droplets radical chemistry involving OH, NO(3), Cl/Cl(2)(-)/ClOH(-), and Br/Br(2)(-)/BrOH(-) gains in importance and pH independent pathways lead to the release of halogens from the particle phase whereas the chemistry in aerosol particles with high electrolyte concentrations is controlled by non-radical reactions at high ionic strengths and relatively low pH values. For the simulation of halogen activation in tropospheric clouds and aqueous aerosol particles in different environments a halogen module was developed including both gas and aqueous phase processes of halogen containing species. This module is coupled to a base mechanism consisting of RACM (Regional Atmospheric Chemistry Mechanism) and the Chemical Aqueous Phase Radical Mechanism CAPRAM 2.4 (MODAC-mechanism). Phase exchange is described by the resistance model by Chemistry of Multiphase Atmospheric Systems, NATO ASI Series, 1986. It can be shown that under cloud conditions the bromine atom is mainly produced by OH initiated reactions, i.e. its concentration maximum is reached at noon. In contrast, the concentration level of chlorine atoms is linked to NO(3) radical chemistry leading to a smaller amplitude between day and night time concentrations. The contribution of radical processes to halogen atom formation in the particle phase is evident, e.g. by halogen atoms which undergo direct phase transfer. Furthermore, the application of the multiphase model for initial concentrations for sea

  12. 21 CFR 886.3920 - Aqueous shunt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Aqueous shunt. 886.3920 Section 886.3920 Food and... OPHTHALMIC DEVICES Prosthetic Devices § 886.3920 Aqueous shunt. (a) Identification. An aqueous shunt is an... Review Guidance of 2/12/90 (K90-1),” and (3) “Aqueous Shunts—510(k) Submissions.”...

  13. Sporostatic and Sporocidal Properties of Aqueous Formaldehyde

    PubMed Central

    Trujillo, Ralph; David, Thomas J.

    1972-01-01

    Aqueous formaldehyde is shown to exert both sporostatic and sporocidal effects on Bacillus subtilis spores. The sporostatic effect is a result of the reversible inhibition of spore germination occasioned by aqueous formaldehyde; the sporocidal effect is due to temperature-dependent inactivation of these spores in aqueous formaldehyde. The physicochemical state of formaldehyde in solution provides a framework with which to interpret both the sporostatic and sporocidal properties of aqueous formaldehyde. PMID:4623282

  14. Dissolution of K-feldspar at CO2-saturated conditions

    NASA Astrophysics Data System (ADS)

    Rosenqvist, Jörgen; Kilpatrick, Andrew D.; Yardley, Bruce W. D.; Rochelle, Christopher A.

    2014-05-01

    Underground storage of carbon dioxide on a very large scale is widely considered to be an essential part of any strategy to reduce greenhouse gas emissions to the atmosphere. Aquifers in deep sedimentary basins have been identified as suitable targets for geological carbon dioxide storage, especially aquifers located in sandstone host rock. This has led to renewed interest in studying the interaction between sandstone minerals and aqueous fluids, as there is a paucity of data for CO2-containing systems at relevant conditions. In an attempt to improve data coverage for important silicate minerals, we have measured the dissolution kinetics of K-feldspar in CO2-saturated fluids over a range of temperatures. K-feldspar fragments were hand-picked from a larger sample, crushed to a narrow size range and cleaned. The grains were reacted with water in batch-type reactors at temperatures from 20°C to 200°C and pressures up to 200 bar, and the dissolution was followed by periodic withdrawal of aliquots of solution. The mineral grains were allowed to react with pure water for a number of weeks before injection of CO2 into the system. Excess CO2 was provided to ensure CO2 saturation in the experimental systems. While the reaction time before injection was not long enough to attain complete equilibrium, it did considerably lower the degree of undersaturation with respect to K-feldspar and helped highlight the effect of CO2 injection into a rock-equilibrated aqueous fluid. At all temperatures studied, injection of CO2 resulted in a rapid increase in the soluble concentrations of K and Si (and also Na from a plagioclase component). The dissolution then reached apparent steady state conditions after a few days, with observed dissolution rates in the range of 1E-9 to 1E-12 mol/m2/s over the temperature range studied. The CO2-saturated solutions maintained mildly acidic conditions throughout the experiments and the observed rates therefore fall roughly between rates measured in

  15. Pretreatment of rapeseed straw by soaking in aqueous ammonia.

    PubMed

    Kang, Kyeong Eop; Jeong, Gwi-Taek; Sunwoo, Changshin; Park, Don-Hee

    2012-01-01

    Pretreatment of lignocellulosic biomass has gained attention for production of biofuels. In this study, pretreatment by soaking in aqueous ammonia was adopted for pretreatment of biomass for ethanol production. A central composite design of response surface methodology was used for optimization of the pretreatment condition of rapeseed straw, with respect to catalyst concentration, pretreatment time, and pretreatment temperature. The most optimal condition for pretreatment of rapeseed straw by soaking in aqueous ammonia was 19.8% of ammonia water, 14.2 h of pretreatment time, and a pretreatment temperature of 69.0 °C. Using these optimal factor values under experimental conditions, 60.7% of theoretical glucose was obtained, and this value was well within the range predicted by the model. SEM results showed that SAA pretreatment of rapeseed straw resulted in increased surface area and pore size, as well as enhanced enzymatic digestibility.

  16. Gold supported on zirconia polymorphs for hydrogen generation from formic acid in base-free aqueous medium

    NASA Astrophysics Data System (ADS)

    Bi, Qing-Yuan; Lin, Jian-Dong; Liu, Yong-Mei; He, He-Yong; Huang, Fu-Qiang; Cao, Yong

    2016-10-01

    Formic acid (FA) has attracted considerable attention as a safe and convenient hydrogen storage material for renewable energy transformation. However, development of an efficient heterogeneous catalyst for selective FA decomposition for ultraclean H2 gas in the absence of any alkalis or additives under mild conditions remains a major challenge. Based on our previous work on Au/ZrO2 as a robust and efficient catalyst for FA dehydrogenation in amine system, we report here ZrO2 with different nanocrystal polymorphs supported Au nanoparticles can achieve near completion of FA dehydrogenation in base-free aqueous medium. Of significant importance is that an excellent rate of up to 81.8 L H2 gAu-1 h-1 in open system and highly pressurized gas of 5.9 MPa in closed one can be readily attained at 80 °C for Au/m-ZrO2. In situ diffuse reflectance infrared Fourier transform (DRIFT) and CO2-temperature programmed desorption (TPD) techniques revealed that Au/m-ZrO2 exhibits a higher density of surface basic sites than Au/t-ZrO2 and Au/a-ZrO2. Basic sites in surface can substantially facilitate crucial FA deprotonation process which appears to be a key factor for achieving high dehydrogenation activity. The H/D exchange between solvent of H2O and substrate of FA was observed by the kinetic isotope effect experiments.

  17. Does ultra-mild wear play any role for dry friction applications, such as automotive braking?

    PubMed

    Osterle, Werner; Dmitriev, A I; Kloss, H

    2012-01-01

    Nanostructured third body films and/or storage of wear debris at the surfaces of the first bodies are deemed as prerequisites of sliding under ultra-mild wear conditions. Since such features have been observed experimentally on brake pads and discs, attempts were undertaken to study their sliding behaviour by modelling on the nanoscopic scale with an approach based on Movable Cellular Automata (MCA). The model rendered the possibility to study the influence of different nanostructures systematically and to assess the impact of different brake pad ingredients on the sliding behaviour, velocity accommodation and friction force stabilization at a sliding contact. Besides providing a review on previously published modelling results, some additional new graphs enabling better visualization of dynamic processes are presented. Although ultra-mild wear conditions were considered to be essential for achieving the desired tribological properties, transitions to mesoscopic and macroscopic wear mechanisms were studied as well. The final conclusion is that ultra-mild wear and corresponding smooth sliding behaviour play an important role during automotive braking, even though temporarily and locally events of severe wear may cause friction instabilities, surface damage and release of coarse wear particles.

  18. Promotion of Viral IRES-Mediated Translation Initiation under Mild Hypothermia

    PubMed Central

    Licursi, Maria; Carmona-Martinez, Ricardo A.; Razavi, Seyd; Hirasawa, Kensuke

    2015-01-01

    Internal ribosome entry site (IRES)-mediated translation is an essential replication step for certain viruses. As IRES-mediated translation is regulated differently from cap-dependent translation under various cellular conditions, we sought to investigate whether temperature influences efficiency of viral IRES-mediated translation initiation by using bicistronic reporter constructs containing an IRES element of encephalomyocarditis virus (EMCV), foot-and-mouth disease virus (FMDV), hepatitis C virus (HCV), human rhinovirus (HRV) or poliovirus (PV). Under mild hypothermic conditions (30 and 35°C), we observed increases in the efficiency of translation initiation by HCV and HRV IRES elements compared to translation initiation at 37°C. The promotion of HRV IRES activity was observed as early as 2 hours after exposure to mild hypothermia. We also confirmed the promotion of translation initiation by HRV IRES under mild hypothermia in multiple cell lines. The expression levels and locations of polypyrimidine tract-binding protein (PTB) and upstream of N-Ras (unr), the IRES trans-acting factors (ITAFs) of HCV and HRV IRES elements, were not modulated by the temperature shift from 37°C to 30°C. Taken together, this study demonstrates that efficiency of translation initiation by some viral IRES elements is temperature dependent. PMID:25951166

  19. Effects of Concept Mapping Instruction on the Vocabulary Acquisition Skills of Seventh-Graders with Mild Disabilities: A Replication Study

    ERIC Educational Resources Information Center

    Palmer, Jessica; Boon, Richard T.; Spencer, Vicky G.

    2014-01-01

    The present investigation replicates and extends an earlier study comparing 2 conditions, a dictionary approach versus a concept mapping model, on the learning of vocabulary words among 4 students with mild disabilities (i.e., emotional and/or behavioral disorders and other health impairments) attending a middle school. An A-B-A-B design was used…

  20. Mild Airflow Limitation during N2 Sleep Increases K-complex Frequency and Slows Electroencephalographic Activity

    PubMed Central

    Nguyen, Chinh D.; Wellman, Andrew; Jordan, Amy S.; Eckert, Danny J.

    2016-01-01

    Study Objectives: To determine the effects of mild airflow limitation on K-complex frequency and morphology and electroencephalogram (EEG) spectral power. Methods: Transient reductions in continuous positive airway pressure (CPAP) during stable N2 sleep were performed to induce mild airflow limitation in 20 patients with obstructive sleep apnea (OSA) and 10 healthy controls aged 44 ± 13 y. EEG at C3 and airflow were measured in 1-min windows to quantify K-complex properties and EEG spectral power immediately before and during transient reductions in CPAP. The frequency and morphology (amplitude and latency of P200, N550 and N900 components) of K-complexes and EEG spectral power were compared between conditions. Results: During mild airflow limitation (18% reduction in peak inspiratory airflow from baseline, 0.38 ± 0.11 versus 0.31 ± 0.1 L/sec) insufficient to cause American Academy of Sleep Medicine-defined cortical arousal, K-complex frequency (9.5 ± 4.5 versus 13.7 ± 6.4 per min, P < 0.01), N550 amplitude (25 ± 3 versus 27 ± 3 μV, P < 0.01) and EEG spectral power (delta: 147 ± 48 versus 230 ± 99 μV2, P < 0.01 and theta bands: 31 ± 14 versus 34 ± 13 μV2, P < 0.01) significantly increased whereas beta band power decreased (14 ± 5 versus 11 ± 4 μV2, P < 0.01) compared to the preceding non flow-limited period on CPAP. K-complex frequency, morphology, and timing did not differ between patients and controls. Conclusion: Mild airflow limitation increases K-complex frequency, N550 amplitude, and spectral power of delta and theta bands. In addition to providing mechanistic insight into the role of mild airflow limitation on K-complex characteristics and EEG activity, these findings may have important implications for respiratory conditions in which airflow limitation during sleep is common (e.g., snoring and OSA). Citation: Nguyen CD, Wellman A, Jordan AS, Eckert DJ. Mild airflow limitation during N2 sleep increases k-complex frequency and slows

  1. Secondary Organic Aerosol Produced from Aqueous Reactions of Phenols in Fog Drops and Deliquesced Particles

    NASA Astrophysics Data System (ADS)

    Smith, J.; Anastasio, C.

    2014-12-01

    The formation and evolution of secondary organic aerosol (SOA) in atmospheric condensed phases (i.e., aqueous SOA) can proceed rapidly, but relatively little is known of the important aqueous SOA precursors or their reaction pathways. In our work we are studying the aqueous SOA formed from reactions of phenols (phenol, guaiacol, and syringol), benzene-diols (catechol, resorcinol, and hydroquinone), and phenolic carbonyls (e.g., vanillin and syringaldehyde). These species are potentially important aqueous SOA precursors because they are released in large quantities from biomass burning, have high Henry's Law constants (KH = 103 -109 M-1 atm-1) and are rapidly oxidized. To evaluate the importance of aqueous reactions of phenols as a source of SOA, we first quantified the kinetics and SOA mass yields for 11 phenols reacting via direct photodegradation, hydroxyl radical (•OH), and with an excited organic triplet state (3C*). In the second step, which is the focus of this work, we use these laboratory results in a simple model of fog chemistry using conditions during a previously reported heavy biomass burning event in Bakersfield, CA. Our calculations indicate that under aqueous aerosol conditions (i.e., a liquid water content of 100 μg m-3) the rate of aqueous SOA production (RSOA(aq)) from phenols is similar to the rate in the gas phase. In contrast, under fog/cloud conditions the aqueous RSOA from phenols is 10 times higher than the rate in the gas phase. In both of these cases aqueous RSOA is dominated by the oxidation of phenols by 3C*, followed by direct photodegradation of phenolic carbonyls, and then •OH oxidation. Our results suggest that aqueous oxidation of phenols is a significant source of SOA during fog events and also during times when deliquesced aerosols are present.

  2. Detection of mild inherited disorders of blood coagulation: current options and personal recommendations.

    PubMed

    Lippi, Giuseppe; Pasalic, Leonardo; Favaloro, Emmanuel J

    2015-08-01

    Although assessment of prior personal and familial bleeding history is an important aspect of the diagnosis of bleeding disorders, patients with mild inherited bleeding disorders are sometimes clinically asymptomatic until presented with a hemostatic challenge. However, bleeding may occur after incursion of trauma or surgery, so detection of these conditions reflects an important facet of clinical and laboratory practice. Mild bleeding disorders may be detected as a result of family studies or following identification of abnormal values in first-line screening tests such as activated partial thromboplastin time, prothrombin time, fibrinogen and global platelet function screen testing, such as the platelet function analyzer. Following determination of abnormal screening tests, subsequent investigation should follow a systematic approach that targets specific diagnostic tests, and including factor assays, full platelet function assays and more extensive specialized hemostasis testing. The current report provides a personal overview on inherited disorders of blood coagulation and their detection.

  3. Rapid and mild purification method for nanoparticles from a dispersed solution using a monolithic silica disk.

    PubMed

    Itoh, Naoki; Santa, Tomofumi; Kato, Masaru

    2015-07-24

    A rapid and mild purification method for nanoparticles using the commercially available monolithic silica disk, MonoSpin(®), was developed. The nanoparticles were purified from a dispersed solution by filtration with the aid of centrifugation at 2290×g for 2min. The purification conditions were rapid, mild, and simple compared with those of the conventional purification methods such as ultracentrifugation, dialysis, size exclusion chromatography, and ultrafiltration. The method was shown to be applicable for the purification of various nanoparticles, regardless of their size (from 21 to 100nm), composition material (silica, polyethylene glycol, and pegylated liposome), and encapsulated molecule (rhodamine 110 and doxorubicin). It was shown that this method is applicable to the purification of a wide range of nanoparticles in many different fields.

  4. Surface Changes in Mild Steel Coupons from the Action of Corrosion-Causing Bacteria

    PubMed Central

    Obuekwe, Christian O.; Westlake, Donald W. S.; Cook, Fred D.; William Costerton, J.

    1981-01-01

    Changes which occur on the surface of mild steel coupons submerged in cultures of an Fe(III)-reducing bacterium, isolated from corroded pipe systems carrying crude oil, were studied microscopically to investigate the interaction between the corrosion-causing bacterium and the corroding mild steel coupon. Under micro-aerobic conditions and in the absence of the bacteria, a dense, crystalline, amorphous coat formed on the surface of the steel coupons. In the presence of bacteria the surface coat was extensively removed, exposing the bare metal to the environment. After about 2 weeks of exposure, the removal of the surface coating was followed by colonization of the metal surface by the bacteria. Colonization was mediated by fibrous, exopolysaccharidic material formed by the bacteria. Extension of studies to other bacteria isolated from crude oil and corroded pipes reveals that the formation of exopolysaccharide fibers and possession of adherent properties are common characteristics of bacteria from crude oil systems. Images PMID:16345735

  5. Effects of mild hypoxia in aviation on mood and complex cognition.

    PubMed

    Legg, S J; Gilbey, A; Hill, S; Raman, A; Dubray, A; Iremonger, G; Mündel, T

    2016-03-01

    Thirty six volunteer air force personnel were sequentially exposed in a randomized balanced order in a hypobaric chamber to 30 min of baseline (sea level) and mild hypoxia induced by a specified altitude (sea level, 8000 ft and 12,000 ft), followed immediately by breathing 100% oxygen from an oro-nasal mask. Mood and complex cognition were assessed. Analysis of variance indicated that mood (fatigue and vigour) remained the same at 8000 ft but fatigue was increased (p = 0.001) and vigour reduced (p = 0.035) at 12,000 ft and was restored by supplementary oxygen. Complex cognition was not significantly altered by the test conditions. The results of this study do not support prior evidence that mild hypoxia equivalent to either 8000 or 12,000 ft, impairs complex cognition, but suggests that some aspects of mood may be affected at 12,000 ft and can be restored by breathing 100% oxygen.

  6. Inferential reading abilities of mildly mentally retarded and nonretarded students.

    PubMed

    Bos, C S; Tierney, R J

    1984-07-01

    The inferential operations of mildly mentally retarded students reading at the intermediate level were investigated using methods based on discourse comprehension theory. We hypothesized that problems encountered in reading by these students are related to difficulties in generating logical inferences. Mildly retarded junior-high students and nonretarded third-grade students of the same reading comprehension level read and recalled a descriptive expository and a narrative passage. On the expository passage mildly retarded students generated the same quantity of inferences as did nonretarded students, but the inferences were qualitatively inferior. On the narrative passage the differences between the two groups were not significant. These findings were discussed in relation to the cognitive functioning of mildly retarded students.

  7. Cognitive vulnerability in moderate, mild, and low seasonality.

    PubMed

    Rohan, Kelly J; Nillni, Yael I; Mahon, Jennifer N; Roecklein, Kathryn A; Sitnikov, Lilya; Haaga, David A F

    2011-12-01

    This study examined the association between cognitive vulnerability factors and seasonality. Students (N = 88), classified based on the Seasonal Pattern Assessment Questionnaire as experiencing moderate (n = 26) or mild (n = 32) seasonality, and nondepressed, low-seasonality controls (n = 30) completed explicit (i.e., dysfunctional attitudes, automatic negative thoughts, seasonal attitudes, and rumination) and implicit (i.e., implicit associations test) measures of cognitive vulnerability at one winter and one nonwinter assessment. Relative to low- and mild-seasonality participants, moderate-seasonality participants endorsed more automatic thoughts and rumination in winter and more dysfunctional attitudes across both seasons. Moderate- and mild-seasonality participants endorsed more maladaptive seasonal attitudes than did low-seasonality participants. All groups demonstrated increased dysfunctional attitudes, automatic thoughts, and rumination and stronger implicit associations about light and dark during the winter. The findings support a possible cognitive mechanism of winter depression onset and/or maintenance unique to individuals with moderate, as opposed to mild, seasonality.

  8. Mild, Moderate, Severe Asthma: What Do Grades Mean?

    MedlinePlus

    ... Text Size Email Print Share Mild, Moderate, Severe Asthma: What Do Grades Mean? Page Content Article Body ... is when assessed at follow-up visits. Intermittent Asthma A child who has symptoms of wheezing and ...

  9. Reading Improvement for Mainstreamed Children Who Are Mildly Mentally Handicapped.

    ERIC Educational Resources Information Center

    Buttery, Thomas J.; Mason, George E.

    1979-01-01

    Covers two major aspects of reading instruction for mildly mentally handicapped children in the regular classroom: a review of their reading characteristics and a presentation of questioning techniques useful for promoting their reading comprehension. (FL)

  10. Toxicity of calcium salts to aqueous microorganisms

    SciTech Connect

    Lakhina, K.G.; Dolganova, A.V.; Yakobi, L.K.

    1983-03-01

    This article investigates the toxicity of calcium to aqueous microogranisms by means of a procedure developed by VNII VODGEO (All-Union Scientific-Research Institute of Water Supply, Sewer Systems, Hydrotechnical Facilities, and Engineering Hydrogeology), with certain changes in the preparation of the culture water. Proposes that with this method, calcium toxicity can be determined for groups of microorganisms that are among the most important in biochemical wastewater treatment and self-purification of water bodies (saprophytes, phase I and II nitrifiers). Finds that calcium in the form of the hydroxide and chloride is nontoxic under the following conditions: for protozoa in concentrations up to 2 g/liter, for saprophytic bacteria up to 3 g/liter, for phase I nitrifiers up to 1 g/liter, and for phase II nitrifiers up to 0.1 g/liter.

  11. Pulse Radiolysis of Aqueous Thiocyanate Solution

    SciTech Connect

    Milosavljevic, Bratoljub H.; LaVerne, Jay A.

    2005-01-13

    The pulse radiolysis of N2O saturated aqueous solutions of KSCN was studied under neutral pH conditions. The observed optical absorption spectrum of the SCN• radical in solution is more complex than previously reported, but it is in good agreement with that measured in the gas phase. Kinetic traces at 330 nm and 472 nm corresponding to SCN• and (SCN)2•¯, respectively, were fit using a Monte Carlo simulation kinetic model. The rate coefficient for the oxidation of SCN¯ ions by OH radicals, an important reaction used in competition kinetics measurements, was found to be 1.4 ± 0.1 x 1010 M-1 s-1, about 30 % higher than the normally accepted value. A detailed discussion of the reaction mechanism is presented.

  12. Exertional compartment syndrome in covert mild hemophilia. A case report.

    PubMed

    Tountas, C P; Ferris, F O; Cobb, S W

    1992-07-01

    A 37-year-old white male experienced unexpected postoperative bleeding after fasciotomy and decompression for left pronator and compartment syndromes of the forearm. He was subsequently diagnosed with a mild form of hemophilia A. One year later, surgery was required for right pronator and compartment syndromes. Pre- and postoperative cryoprecipitate infusions controlled bleeding following the second operation until the patient discontinued his infusions, resulting in a wound hematoma. Covert mild hemophilia is implicated in the pathogenesis of his compartment syndromes.

  13. Cesium recovery from aqueous solutions

    DOEpatents

    Goodhall, C. A.

    1960-09-13

    A process for recovering cesium from aqueous solutions is given in which precipitation on zinc ferricyanide is used. The precipitation is preferably carried out in solutions containing at least 0.0004M zinc ferricyanide, an acidity ranging from 0.2N mineral acid to 0.61N acid deficiency, and 1 to 2.5M aluminum nitrate. (D.L.C.)

  14. The Melting of Aqueous Foams

    NASA Technical Reports Server (NTRS)

    Durian, Douglas J.; Gopal, Anthony D.; Vera, Moin U.; Langer, Stephen A.

    1996-01-01

    Diffusing-wave spectroscopy measurements show that ordinarily solid aqueous foams flow by a series of stick-slip avalanche-like rearrangements of neighboring bubbles from one tight packing configuration to another. Contrary to a recent prediction, the distribution of avalanche sizes do not obey a power-law distribution characteristic of self-organized criticality. This can be understood from a simple model of foam mechanics based on bubble-bubble interactions.

  15. Stabilized aqueous hydrogen peroxide solution

    SciTech Connect

    Malin, M.J.; Sciafani, L.D.

    1988-05-17

    This patent describes a stabilized aqueous hydrogen peroxide solution having a pH below 7 and an amount of Ferric ion up to about 2 ppm comprising hydrogen peroxide, acetanilide having a concentration which ranges between 0.74 M Mol/L and 2.22 mMol/L, and o-benzene disulfonic acid or salt thereof at a concentration between about 0.86 mMol/L to about 1.62 mMol/L.

  16. A better mild traumatic brain injury model in the rat.

    PubMed

    Takeuchi, Satoru; Nawashiro, Hiroshi; Sato, Shunichi; Kawauchi, Satoko; Nagatani, Kimihiro; Kobayashi, Hiroaki; Otani, Naoki; Osada, Hideo; Wada, Kojiro; Shima, Katsuji

    2013-01-01

    The primary pathology associated with mild -traumatic brain injury (TBI) is selective axonal injury, which may characterize the vast majority of blast-induced TBIs. Axonal injuries in cases of mild TBI have been considered to be the main factors responsible for the long-lasting memory or attentional impairment in affected subjects. Among these axonal injuries, recent attention has been focused on the cingulum bundle (CB). Furthermore, recent studies with diffusion tensor MR imaging have shown the presence of injuries of the CB in cases of mild TBI in humans. This study aimed to provide a better laboratory model of mild TBI.Sprague-Dawley rats were subjected to mild TBI using laser-induced shock waves (LISW) (sham, 0.5 J/cm(2), or 1.0 J/cm(2); n = 4 per group). Bodian-stained brain sections 14 days after LISW at 0.5 J/cm(2) or 1.0 J/cm(2) showed a decrease in the CB axonal density compared with the sham group, whereas there were no differences in the axonal density of the corpus callosum.The present study shows that this model is capable of reproducing the histological changes associated with mild TBI. PMID:23564112

  17. Mild extractability and bioavailability of polycyclic aromatic hydrocarbons in soil

    SciTech Connect

    Tang, J.; Alexander, M.

    1999-12-01

    A study was conducted to determine the relationship between bioavailability of unaged and aged polycyclic aromatic hydrocarbons (PAHs) in soil and the amounts detected by mild solvent extraction. More aged than unaged anthracene remained in Lima loam following introduction of earthworms (Eisenia foetida), a mixed culture containing anthracene-degrading microorganisms, or earthworms or wheat after bacterial biodegradation of the compound. Aging decreased the percentage of anthracene recovered by mild extraction with n-butanol from soil following introduction of earthworms, growth of wheat, biodegradation by bacteria, or when maintained sterile. Biodegradation resulted in a marked decrease in the percentage of aged and unaged anthracene recovered from soil by mild extraction with n-butanol or ethyl acetate. Aging of fluoranthene and pyrene decreased the amount removed by mild extraction with n-butanol, ethyl acetate, and propanol. The uptake of aged and unaged anthracene, fluoranthene, and pyrene by earthworms was correlated with the amounts recovered from soil by mild extraction with n-butanol, propanol, and ethyl acetate. The retention of aged and unaged anthracene by wheat and barley was correlated with the amounts recovered from soil by the same procedure. The authors suggest that mild extraction with organic solvents can be used to predict the bioavailability of PAHs in soil.

  18. Pyrrolidine as a cogwheel-like scaffold for the deployment of diverse functionality through cycloaddition reactions of metallo-1,3-dipoles in aqueous media.

    PubMed

    Hanessian, S; Bayrakdarian, M

    2000-03-01

    The reaction of glycinatocopper complexes with cinnamaldehydes under mildy basic aqueous conditions, affords polysubstituted prolines, which can be systematically modified in a number of chemoselective transformations. PMID:10743941

  19. Geochemical Modeling Of Aqueous Systems

    1995-09-07

    EQ3/6 is a software package for geochemical modeling of aqueous systems. This description pertains to version 7.2b. It addresses aqueous speciation, thermodynamic equilibrium, disequilibrium, and chemical kinetics. The major components of the package are EQ3NR, a speciation-solubility code, and EQ6 a reaction path code. EQ3NR is useful for analyzing groundwater chemistry data, calculating solubility limits, and determining whether certain reactions are in states of equilibrium or disequilibrium. It also initializes EQ6 calculations. EQ6 models themore » consequences of reacting an aqueous solution with a specified set of reactants (e.g., minerals or waste forms). It can also model fluid mixing and the effects of changes in temperature. Each of five supporting data files contain both standard state and activity coefficient-related data. Three support the use of the Davies or B-dot equations for the activity coefficients; the other two support the use of Pitzer''s equations. The temperature range of the thermodynamic data on the data files varies from 25 degrees C only to 0-300 degrees C.« less

  20. Brain perfusion correlates of visuoperceptual deficits in Mild Cognitive Impairment and mild Alzheimer’s disease

    PubMed Central

    Alegret, Montserrat; Vinyes-Junqué, Georgina; Boada, Mercè; Martínez-Lage, Pablo; Cuberas, Gemma; Espinosa, Ana; Roca, Isabel; Hernández, Isabel; Valero, Sergi; Rosende-Roca, Maitée; Mauleón, Ana; Becker, James T.; Tárraga, Lluís

    2012-01-01

    Background Visuoperceptual processing is impaired early in the clinical course of Alzheimer’s disease (AD). The 15-Objects Test (15-OT) detects such subtle performance deficits in Mild Cognitive Impairment (MCI) and mild AD. Reduced brain perfusion in the temporal, parietal and prefrontal regions have been found in early AD and MCI patients. Objectives To confirm the role of the 15-OT in the diagnosis of MCI and AD, and to investigate the brain perfusion correlates of visuoperceptual dysfunction (15-OT) in subjects with MCI, AD and normal aging. Methods Forty-two AD, 42 MCI and 42 healthy elderly control (EC) subjects underwent a brain Single Photon Emission Tomography (SPECT) and separately completed the 15-OT. An analysis of variance compared 15-OT scores between groups. SPM5 was used to analyse the SPECT data. Results 15-OT performace was impaired in the MCI and AD patients. In terms of the SPECT scans, AD patients showed reduced perfusion in temporal-parietal regions, while the MCI subjects had decreased perfusion in the middle and posterior cingulate. When MCI and AD groups were compared, a significant brain perfusion reduction was found in temporo-parietal regions. In the whole sample, 15-OT performance was significantly correlated with the clinical dementia rating scores, and with the perfusion in the bilateral posterior cingulate and the right temporal pole, with no significant correlation in each separate group. Conclusion Our findings suggest that the 15-OT performance provides a useful gradation of impairment from normal aging to AD, and it seems to be related to perfusion in the bilateral posterior cingulate and the right temporal pole. PMID:20555146