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1

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

NASA Technical Reports Server (NTRS)

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.

Weber, Arthur L.

2004-01-01

2

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

NASA Technical Reports Server (NTRS)

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.

Weber, Arthur L.

2003-01-01

3

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

NASA Technical Reports Server (NTRS)

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 (deltaG > +3.5 kcal/mol); and (3) the dependence of carbon group transformation energy on the functional group class (i.e., oxidation state) of participating groups that in turn is contingent on prior reactions and precursors in the synthetic pathway.

Weber, Arthur L.

2002-01-01

4

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

PubMed

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. PMID:24762698

Ren, Yanlin; Fan, Guangyin; Wang, Chenyu

2014-06-15

5

The Pd-catalyzed hydrodechlorination of chlorophenols in aqueous solutions under mild conditions: a promising approach to practical use in wastewater.  

PubMed

Catalytic hydrotreating of chlorophenols was carried out in water with Pd/C at 25 degrees C under atmospheric pressure. 1.0% (w/w) monocholophenols was completely dechlorinated within 60 min. Phenol, cyclohexanone and cyclohexanol were formed. In contrast to the dechlorination of monochlorophenols, the hydrogenation reaction of polychlorinated phenols became difficult and reaction rates were strongly dependent upon the number of the chlorine atoms. The solvent property had a considerably important influence on the dechlorination reaction. Water as a solvent showed more advantages than organic solvents. It was much easier to be hydrodechlorinated for chlorophenols in aqueous solutions. However, the presence of THF, dioxane, DMSO or DMF in water was disadvantageous to the reaction and easily to cause Pd/C deactivation. Additionally, when different halogenated organic compounds were present in aqueous solution, the dehalogenation reaction was the competitive hydrogenation process. PMID:19477071

Xia, Chuanhai; Liu, Ying; Zhou, Shiwei; Yang, Cuiyun; Liu, Sujing; Xu, Jie; Yu, Junbao; Chen, Jiping; Liang, Xinmiao

2009-09-30

6

Selective hydrogen production from methanol with a defined iron pincer catalyst under mild conditions.  

PubMed

Molecularly well-defined iron pincer complexes promote the aqueous-phase reforming of methanol to carbon dioxide and hydrogen, which is of interest in the context of a methanol and hydrogen economy. For the first time, the use of earth-abundant iron complexes under mild conditions for efficient hydrogen generation from alcohols is demonstrated. PMID:24339396

Alberico, Elisabetta; Sponholz, Peter; Cordes, Christoph; Nielsen, Martin; Drexler, Hans-Joachim; Baumann, Wolfgang; Junge, Henrik; Beller, Matthias

2013-12-23

7

Solvolytic liquefaction of wood under mild conditions  

SciTech Connect

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.

Yu, S.M.

1982-04-01

8

Corrosion inhibition of mild steel in neutral aqueous solution by new triazole derivatives  

Microsoft Academic Search

Selected triazole derivatives have been synthesised and evaluated as corrosion inhibitors for mild steel in natural aqueous environment by weight loss, potentiodynamic polarisation and ac impedance methods. All the condensed products showed good inhibition efficiency (IE). The effect of changing functional groups of some triazole derivatives on their inhibition efficiency was also reported using weight loss and potentiodynamic technique. 3-Salicylalidene

S Ramesh; S Rajeswari

2004-01-01

9

Dialkylimidazolium ionic liquids hydrolyze cellulose under mild conditions.  

PubMed

The average molecular weight of cellulose derived from filter paper, poplar, and Avicel decreases by up to two orders of magnitude during typical mild dissolution protocols using ionic liquids (ILs). About an order of magnitude greater cellulose depolymerization rate during ionic liquid dissolution occurs in 1-butyl-3-methylimidazolium chloride (BmimCl) and 1-ethyl-3-methylimidazolium chloride (EmimCl) compared to 1-ethyl-3-methylimidazolium acetate (EmimOAc), and, unintuitively, greater IL purity results in greater cellulose depolymerization. The following data support the mechanism of cellulose hydrolysis to be acid-catalyzed: (i) increase in number of reducing ends following cellulose dissolution in IL; (ii) addition of N-methylimidazolium base suppresses cellulose depolymerization during dissolution in IL; (iii) small amounts of glucose and traces of hydroxymethyl furfural are present following cellulose dissolution in IL. The acid is presumably synthesized via IL decomposition to generate a carbene and proton, consistent with hypothesis derived from molecular modeling. Titration experiments conducted here measure the amount of acid synthesized to be in the 4000 ppm range for high-purity BmimCl IL during mild processing conditions for cellulose dissolution. This data is relevant for understanding the extent of IL decomposition during biomass dissolution. PMID:22550059

Gazit, Oz M; Katz, Alexander

2012-08-01

10

Uranium dioxide dissolution under acidic aqueous conditions  

SciTech Connect

Understanding of the long-term dissolution of waste forms in groundwater is required for the safe disposal of high level nuclear waste in a geologic repository, because waste-form radionuclides could be released by dissolution and transported in groundwater. The dissolution of the uranium dioxide (UO{sub 2}) matrix in spent nuclear fuel is considered the rate-limiting step for release of radioactive fission products. The intrinsic UO{sub 2} dissolution rate sets an upper limit on the aqueous radionuclide release rate. Unsaturated spent fuel tests have shown that pH`s of leachates have decreased to a range of 4 to 6, presumably due to air radiolysis that oxidizes nitrogen, producing nitric acid. Dissolution rates under such acidic conditions may be different than those previously reported for alkaline groundwater conditions. No dissolution rate measurements of UO{sub 2} or spent fuel have been reported for acidic conditions possibly relevant to a geologic repository. The purpose of our work has been to measure the intrinsic dissolution rates of uranium dioxide under acidic conditions that are relevant to a repository and allow for modeling. Experiments have been completed at room-temperature and 75 C, pH`s of 4 and 6, and air and oxygen saturated aqueous solutions. These are compared with earlier work on spent fuel and UO{sub 2} using alkaline solutions.

Steward, S.A.; Mones, E.T.

1995-11-20

11

Palladium-catalyzed alkenylation of ketone enolates under mild conditions.  

PubMed

A protocol for a mild, catalytic, intermolecular alkenylation of ketone enolates has been developed using a Pd/Q-Phos catalyst. Efficient intermolecular coupling of a variety of ketones with alkenyl bromides was achieved with a slight excess of LiHMDS and temperatures down to 0 °C. PMID:25032503

Grigalunas, Michael; Ankner, Tobias; Norrby, Per-Ola; Wiest, Olaf; Helquist, Paul

2014-08-01

12

Sodium nitrite catalyzed aerobic oxidative deoximation under mild conditions.  

PubMed

A mild, simple process for the effective deoximation of a wide range of ketoximes and aldoximes has been developed, which utilizes available NaNO(2) as the catalyst and molecular oxygen as the green oxidant. Notably Amberlyst-15, which acts as the initiator of NaNO(2), can be reused without regeneration. This environmentally benign protocol could provide a valuable synthetic method for practical applications. PMID:21528915

Zhang, Guofu; Wen, Xin; Wang, Yong; Mo, Weimin; Ding, Chengrong

2011-06-01

13

Explosivity Conditions of Aqueous Solutions and L. Mercury2  

E-print Network

1 Explosivity Conditions of Aqueous Solutions R. Thiéry1 and L. Mercury2 Revised version February of explosive boiling and gas exsolution of aqueous solutions from a thermodynamic point of view. Indeed, the kinetic nature of these processes, hence their explosivity, can be assessed by considering their relation

Paris-Sud XI, Université de

14

Pd-Catalyzed Synthesis of Ar-SCF3 Compounds under Mild Conditions  

E-print Network

Good to excellent yields of aryl trifluoromethyl sulfides, which are an important class of compounds in both the pharmaceutical and agrochemical areas, can be achieved under mild conditions by the Pd-catalyzed reaction of ...

Teverovskiy, Georgiy

15

Integration of advanced oxidation processes at mild conditions in wet scrubbers for odourous sulphur compounds treatment.  

PubMed

The effectiveness of different advanced oxidation processes on the treatment of a multicomponent aqueous solution containing ethyl mercaptan, dimethyl sulphide and dimethyl disulphide (0.5 mg L(-1) of each sulphur compound) was investigated with the objective to assess which one is the most suitable treatment to be coupled in wet scrubbers used in odour treatment facilities. UV/H2O2, Fenton, photo-Fenton and ozone treatments were tested at mild conditions and the oxidation efficiency obtained was compared. The oxidation tests were carried out in magnetically stirred cylindrical quartz reactors using the same molar concentration of oxidants (hydrogen peroxide or ozone). The results show that ozone and photo-Fenton are the most efficient treatments, achieving up to 95% of sulphur compounds oxidation and a mineralisation degree around 70% in 10 min. Furthermore, the total costs of the treatments taking into account the capital and operational costs were also estimated for a comparative purpose. The economic analysis revealed that the Fenton treatment is the most economical option to be integrated in a wet scrubber to remove volatile organic sulphur compounds, as long as there are no space constraints to install the required reactor volume. In the case of reactor volume limitation or retrofitting complexities, the ozone and photo-Fenton treatments should be considered as viable alternatives. PMID:24873715

Vega, Esther; Martin, Maria J; Gonzalez-Olmos, Rafael

2014-08-01

16

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

PubMed

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

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

2014-12-01

17

Preparation and Characterization of Colloidal Silica Particles under Mild Conditions  

ERIC Educational Resources Information Center

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…

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

2012-01-01

18

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

PubMed

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

Cohen, Daniel T; Buchwald, Stephen L

2015-01-16

19

CHEMOSELECTIVE N-NITROSATION OF SECONDARY AMINES UNDER MILD AND HETEROGENEOUS CONDITIONS  

Microsoft Academic Search

A combination of iodic or periodic acids and sodium nitrite in the presence of wet SiO2 was used as an effective nitrosating agent for the nitrosation of secondary amines to their corresponding nitroso derivatives under mild and heterogeneous conditions in excellent yields.

Mohammad Ali Zolfigol; Arash Ghorbani Choghamarani; Farhad Shirini; Hassan Keypour; Sadegh Salehzadeh

2001-01-01

20

N-NITROSATION OF SECONDARY AMINES UNDER MILD AND HETEROGENEOUS CONDITIONS  

Microsoft Academic Search

A combination of potassium monopersulfate and sodium nitrite in the presence of wet SiO2 was used as an effective nitrosating agent for the nitrosation of secondary amines to their corresponding nitroso derivatives under mild and heterogeneous conditions in excellent yields.

Mohammad Ali Zolfigol; Mojtaba Bagherzadeh; Arash Ghorbani Choghamarani; Hassan Keypour; Sadegh Salehzadeh

2001-01-01

21

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

NASA Technical Reports Server (NTRS)

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 3.9. Fe hydrolysis reactions on Mars is another source of protons that would have contributed to acidity. The presence of SO2 from volcanic processes could also have contributed to geochemical acidification. These sources of acidity competed with base-forming cations that resulted in mildly acidic solutions that were not favorable for carbonate formation but may have allowed for Fe/Mg smectite formation. Noachian to early Hesperian Mars could have been mildly acidic, allowing Fe/Mg smectite formation but preventing widespread carbonate deposition. This paradigm shift from an early Mars that was neutral-alkaline to mildly acidic may possibly explain why there is a disparity between the occurrence of carbonate and Fe/Mg smectites. Potential microbiological activity would not be eliminated under a mildly acidic Mars; however, there could be tighter constraints as to the type and species of microbiology that could exist.

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

2011-01-01

22

Corrosion inhibition of mild steel by schiff base compounds in various aqueous solutions: part 1  

Microsoft Academic Search

The corrosion inhibition by Schiff base compounds derived from diamines and o-hydroxy, o-methoxy aromatic aldehydes was investigated by weight loss, electrochemical measurements and surface analysis of SS 400 in various aqueous solutions such as tap water (LC), concentrated tap water (HC) and HCl solutions. The maximum inhibition efficiency (?) of N,N?-bis (salicylaldehyde)-1,12-diaminododecane (Saldn) for SS 400 in HCl solution approached

H Shokry; M Yuasa; I Sekine; R. M Issa; H. Y El-baradie; G. K Gomma

1998-01-01

23

Selective formation of adjacent stereocenters by allylboration of ketones under mild neutral conditions.  

PubMed

Allylboronic acids readily react with a broad variety of ketones, affording homoallylic alcohols with adjacent quaternary and tertiary stereocenters. The reaction proceeds with very high anti stereoselectivity even if the substituents of the keto group have a similar size. ?-Keto acids react with syn stereoselectivity probably due to the formation of acyl boronate intermediates. The allylation reactions proceed without added acids/bases under mild conditions. Because of this, many functionalities are tolerated even with in situ generated allylboronic acids. PMID:23621130

Alam, Rauful; Raducan, Mihai; Eriksson, Lars; Szabó, Kálmán J

2013-05-17

24

Corrosion Mechanisms of Mild Steel in Aqueous CO2 SolutionsThu Tran Institute for Corrosion and Multiphase Technology, Ohio University  

E-print Network

Corrosion Mechanisms of Mild Steel in Aqueous CO2 SolutionsThu Tran Institute for Corrosion," Corrosion Science 41, (1999): pp. 117-139. [2] E. Remita, B. Tribollet, E. Sutter, V. Vivier, F. Ropital contribution of the buffering effect," Corrosion Science 50, (2008): pp. 1433-1440. [3] C. DeWaard and D

Botte, Gerardine G.

25

Mild-condition synthesis of allenes from alkynes and aldehydes mediated by tetrahydroisoquinoline (THIQ).  

PubMed

A practical 1,2,3,4-tetrahydroisoquinoline (THIQ)-mediated synthesis of 1,3-disubstituted allenes from terminal alkynes and aldehydes under mild conditions in the presence of CuBr first and then ZnI2 was reported. This telescoped allene synthesis reaction includes three consecutive steps and two reactions: first, a room-temperature CuBr-catalyzed synthesis of propargylamines, exo-yne-THIQs, from terminal alkynes, aldehydes, and THIQ, then filtration of the CuBr catalyst, and finally the ZnI2-mediated allene synthesis from the generated exo-yne-THIQs under mild conditions (either at room temperature or heating at 50 or 75 °C). A wide range of aliphatic or aromatic aldehydes and terminal alkynes are tolerated, affording the allene products in up to 92% yield. Especially, temperature-sensitive aldehydes can be used in the reaction system. Preliminary exploration of the asymmetric allene synthesis has also been conducted, and a moderate enantioselectivity has been achieved. Finally, the relative reactivities of several secondary amines were compared with THIQ, showing that THIQ is the best of these amines in the synthesis of allenes under mild reaction conditions. PMID:24266693

Jiang, Guo-Jie; Zheng, Qin-Heng; Dou, Meng; Zhuo, Lian-Gang; Meng, Wei; Yu, Zhi-Xiang

2013-12-01

26

Self-assembled monolayers of flufenaminate anions on mild steel surface formed in aqueous solution  

NASA Astrophysics Data System (ADS)

Adsorption of derivative of phenylanthranilic acid - flufenamic acid (FFA) on the "oxide-free" and oxidized surface of mild steel in neutral borate buffer solution was studied by ellipsometry and XPS. Anodic polarization curves reveal that complete suppression of the anodic dissolution of iron is achieved at FFA concentration Cin = 3.8 mM. Besides, adding FFA substantially shifts the pitting potential from 0.06 V to 0.67 V. Ellipsometric studies have shown that at the applied potential -0.65 V, when the surface is free from the oxide layer, FFA forms monomolecular layer. To characterize the surface layers formed after exposing the sample in 5 mM FFA solution the XPS was used to assess the composition and the thickness of the layers. Using the intensities of the Fe 2p, Fe 3p, N 1s, F 1s, O 1s and C 1s and analyzing the angle resolved XPS data the FFA molecules have been shown to form monomolecular layer in which FFA is (vertically or slightly inclined) anchored by iron cations through oxygen atoms of carboxyl group to the surface and the fluorine atoms of CF 3 groups form the utmost layer. Similar orientation is also assumed for FFA molecules adsorbed on the oxidized iron surface. It seems that the layer formed by FFA or similar molecules may serve a robust interface for grafting other substances on such a functionalized surface.

Kazansky, Leonid P.; Kuznetsov, Yuri I.; Andreeva, Nina P.; Bober, Yana G.

2010-12-01

27

Au(I)/Au(III)-catalyzed Sonogashira-type reactions of functionalized terminal alkynes with arylboronic acids under mild conditions  

PubMed Central

Summary A straightforward, efficient, and reliable redox catalyst system for the Au(I)/Au(III)-catalyzed Sonogashira cross-coupling reaction of functionalized terminal alkynes with arylboronic acids under mild conditions has been developed. PMID:21804876

Qian, Deyun

2011-01-01

28

Novel ?-arylnitriles synthesis via Ni-catalyzed cross-coupling of ?-bromonitriles with arylboronic acids under mild conditions.  

PubMed

An applicable and easy-handling Ni-catalyst can be used to promote direct arylation of ?-bromonitriles with various arylboronic acids to construct ?-arylnitriles under mild conditions. The methodology tolerates ?-hydrogens and functional groups in the substrates. PMID:21677998

Yang, Yingying; Tang, Shan; Liu, Chao; Zhang, Huimin; Sun, Zhexun; Lei, Aiwen

2011-08-01

29

Efficient Chemisorption of Organophosphorous Redox Probes on Indium Tin Oxide Surfaces under Mild Conditions.  

PubMed

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. PMID:25611977

Forget, Amélie; Limoges, Benoît; Balland, Véronique

2015-02-17

30

Organic cation transporter inhibition increases medial hypothalamic serotonin under basal conditions and during mild restraint  

PubMed Central

The dorsomedial hypothalamus (DMH) has been implicated in the coordination of stress responses. Restraint stress or systemic corticosterone (CORT) treatment induces a rapid increase in tissue concentrations of serotonin (5-hydroxytryptamine; 5-HT) in the DMH. Although the mechanism for rapid changes in 5-HT concentrations in the DMH is not clear, earlier results suggest that stress-induced increases in CORT may inhibit 5-HT transport from the extracellular fluid by acting on corticosterone-sensitive organic cation transporters (OCTs). We tested the hypothesis that perfusion of the medial hypothalamus (MH), which includes the DMH, with the OCT blocker decynium 22 (D-22) would potentiate the effects of mild restraint on extracellular 5-HT. Male Sprague-Dawley rats, implanted with a microdialysis probe into the MH, were treated with reverse-dialysis of D-22 (20 ?M; 40 min) or vehicle and subjected to either 40 min mild restraint or undisturbed control conditions. Perfusates collected from a separate group of rats were evaluated for the effect of restraint on extracellular CORT concentrations in the MH. Reverse dialysis of D-22 induced an increase (200%) in extracellular 5-HT concentrations in the MH in undisturbed control rats. Restraint in the absence of D-22 did not significantly affect MH CORT or 5-HT concentrations. However, perfusion of the MH with D-22 during restraint led to an increased magnitude and duration of extracellular 5-HT concentrations, relative to D-22 by itself. These results are consistent with the hypothesis that OCTs in the DMH contribute to the clearance of 5-HT from the extracellular fluid under both baseline conditions and mild restraint. PMID:20171957

Feng, Na; Lowry, Christopher A.; Lukkes, Jodi L.; Orchinik, Miles; Forster, Gina L.; Renner, Kenneth J.

2010-01-01

31

Analysis of saccharification in Brachypodium distachyon stems under mild conditions of hydrolysis  

PubMed Central

Background Brachypodium distachyon constitutes an excellent model species for grasses. It is a small, easily propagated, temperate grass with a rapid life cycle and a small genome. It is a self-fertile plant that can be transformed with high efficiency using Agrobacteria and callus derived from immature embryos. In addition, considerable genetic and genomic resources are becoming available for this species in the form of mapping populations, large expressed sequence tag collections, T-DNA insertion lines and, in the near future, the complete genome sequence. The development of Brachypodium as a model species is of particular value in the areas of cell wall and biomass research, where differences between dicots and grasses are greatest. Here we explore the effect of mild conditions of pretreatment and hydrolysis in Brachypodium stem segments as a contribution for the establishment of sensitive screening of the saccharification properties in different genetic materials. Results The non-cellulosic monosaccharide composition of Brachypodium is closely related to grasses of agricultural importance and significantly different from the dicot model Arabidopsis thaliana. Diluted acid pretreatment of stem segments produced significant release of sugars and negatively affected the amount of sugars obtained by enzymatic hydrolysis. Monosaccharide and oligosaccharide analysis showed that the hemicellulose fraction is the main target of the enzymatic activity under the modest hydrolytic conditions used in our assays. Scanning electron microscopy analysis of the treated materials showed progressive exposure of fibrils in the stem segments. Conclusion Results presented here indicate that under mild conditions cellulose and hemicellulose are hydrolysed to differing extents, with hemicellulose hydrolysis predominating. We anticipate that the sub-optimal conditions for hydrolysis identified here will provide a sensitive assay to detect variations in saccharification among Brachypodium plants, providing a useful analytical tool for identifying plants with alterations in this trait. PMID:18945335

Gomez, Leonardo D; Bristow, Jennifer K; Statham, Emily R; McQueen-Mason, Simon J

2008-01-01

32

Mild solutions to a measure-valued mass evolution problem with flux boundary conditions  

E-print Network

We investigate the well-posedness and approximation of mild solutions to a class of linear transport equations on the unit interval $[0,1]$ endowed with a linear discontinuous production term, formulated in the space $\\mathcal{M}([0,1])$ of finite Borel measures. Our working technique includes a detailed boundary layer analysis in terms of a semigroup representation of solutions in spaces of measures able to cope with the passage to the singular limit where thickness of the layer vanishes. We obtain not only a suitable concept of solutions to the chosen measure-valued evolution problem, but also derive convergence rates for the approximation procedure and get insight in the structure of flux boundary conditions for the limit problem.

Joep H. M. Evers; Sander C. Hille; Adrian Muntean

2014-12-20

33

Modification of neodymium-doped ZnO hybrid nanoparticles under mild hydrothermal conditions  

NASA Astrophysics Data System (ADS)

The morphology and particle size of neodymium-doped ZnO hybrid nanoparticles were tailored through fabrication under mild hydrothermal conditions (T = 150-250 °C, P = autogeneous, t = 18 h) for the first time using two surface modifiers: caprylic acid and n-butylamine. Characterization of these nanoparticles was carried out using powder XRD, FTIR, SEM, zeta-potential analysis and UV-vis spectroscopy. The results revealed that modification of ZnO nanoparticles using neodymium as a dopant and caprylic acid or n-butylamine as a surfactant could change the optical and physical properties of the surface-modified neodymium-doped ZnO hybrid nanoparticles. The work proved the efficiency of caprylic acid and n-butylamine as suitable surfactants for surface modification of neodymium-doped ZnO hybrid nanoparticles.

Shahmoradi, Behzad; Soga, K.; Ananda, S.; Somashekar, R.; Byrappa, K.

2010-07-01

34

Continuous D-fructose dehydration to 5- hydroxymethylfurfural under mild conditions.  

PubMed

The dehydration of D-fructose to 5-hydroxymethylfurfural was studied under single-phase conditions in the low boiling solvent 1,4-dioxane at moderate temperatures in the presence of the solid acid-catalyst Amberlyst-15. The reaction was first examined and optimized under batch conditions, where it was found that the yield could be increased up to 75?% by adding small amounts of DMSO. Subsequently, the reaction was performed under continuous flow in a fixed bed reactor. Internal and external mass transfer limitations could be eliminated by changing the particle size and by adjusting the flow rate. Under continuous conditions, the HMF yield could be further increased to 92?%; the space-time yield was found to be 75 times higher compared to the batch case. A long-term stability test (96?h), including solvent regeneration, demonstrated that the catalyst is stable over time. Additionally, it was shown that even small amounts of water have a negative effect on the HMF yield. Overall, the present system shows a good alternative to other systems presented in literature because high space-time yields and selectivities were obtained under relatively mild and continuous conditions. PMID:22761084

Aellig, Christof; Hermans, Ive

2012-09-01

35

Enzymatic Formulation Capable of Degrading Scrapie Prion under Mild Digestion Conditions  

PubMed Central

The prion agent is notoriously resistant to common proteases and conventional sterilisation procedures. The current methods known to destroy prion infectivity such as incineration, alkaline and thermal hydrolysis are harsh, destructive, environmentally polluting and potentially hazardous, thus limit their applications for decontamination of delicate medical and laboratory devices, remediation of prion contaminated environment and for processing animal by-products including specified risk materials and carcases. Therefore, an environmentally friendly, non-destructive enzymatic degradation approach is highly desirable. A feather-degrading Bacillus licheniformis N22 keratinase has been isolated which degraded scrapie prion to undetectable level of PrPSc signals as determined by Western Blot analysis. Prion infectivity was verified by ex vivo cell-based assay. An enzymatic formulation combining N22 keratinase and biosurfactant derived from Pseudomonas aeruginosa degraded PrPSc at 65°C in 10 min to undetectable level -. A time-course degradation analysis carried out at 50°C over 2 h revealed the progressive attenuation of PrPSc intensity. Test of residual infectivity by standard cell culture assay confirmed that the enzymatic formulation reduced PrPSc infectivity to undetectable levels as compared to cells challenged with untreated standard scrapie sheep prion (SSBP/1) (p-value?=?0.008 at 95% confidence interval). This novel enzymatic formulation has significant potential application for prion decontamination in various environmentally friendly systems under mild treatment conditions. PMID:23874511

Okoroma, Emeka A.; Purchase, Diane; Garelick, Hemda; Morris, Roger; Neale, Michael H.; Windl, Otto; Abiola, Oduola O.

2013-01-01

36

Facile one-step fabrication of magnetite particles under mild hydrothermal conditions  

NASA Astrophysics Data System (ADS)

Hydrophilic magnetite particles for biological applications were synthesized by hydrothermal method in the presence of D-Glucose as both reducing and capping agent in a facile, one-step, low energy and environmentally friendly route. The role of D-Glucose as a reducing agent in the formation of magnetite particles under mild hydrothermal conditions has been investigated. The absence of D-Glucose results in the formation of hematite. The magnetite particles synthesized were characterized using powder X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy, High Resolution Scanning Electron Microscopy (HR-SEM), Dynamic Light Scattering (DLS) and Vibrating Sample Magnetometery (VSM). The influence of the quantity of D-Glucose used and the reaction duration on the formation of magnetite were studied. DLS and HR-SEM results show that the size of the particles was in nano- to micron range. The antioxidant potency of the particles was confirmed using DPPH assay, where 2,2- Diphenyl-1-picrylhydrazyl was used as a source of free radicals. Hence the magnetite particles obtained could be considered for the use in various biological applications.

Keerthana, D. Shanthini; Namratha, K.; Byrappa, K.; Yathirajan, H. S.

2015-03-01

37

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

38

Indole synthesis from N-allenyl-2-iodoanilines under mild conditions mediated by samarium(II) diiodide.  

PubMed

A novel method for indole skeleton synthesis under mild conditions mediated by samarium(ii) diiodide has been developed. The reaction of N-allenyl-2-iodoaniline derivatives with SmI2 in the presence of HMPA and i-PrOH at 0 °C afforded indole derivatives in high yields. PMID:25072695

Iwasaki, Hiroki; Suzuki, Kenji; Yamane, Mitsunari; Yoshida, Shohei; Kojima, Naoto; Ozeki, Minoru; Yamashita, Masayuki

2014-09-21

39

Aryl ether as a Negishi coupling partner: an approach for constructing C-C bonds under mild conditions.  

PubMed

An etheric Negishi coupling: The first cross-coupling reaction between aryl alkyl ethers and dianion-type zincate reagents to afford biaryl compounds through selective cleavage of the etheric C(sp(2))-O bond was developed. Dianion-type zincates showed excellent reactivity toward the aromatic ethers under mild conditions, with good functional group compatibility (see scheme). PMID:22374683

Wang, Chao; Ozaki, Takashi; Takita, Ryo; Uchiyama, Masanobu

2012-03-19

40

ANTIBODY PURIFICATION USING CAPRYLIC ACID In mildly acidic conditions, the addition of short-chain fatty acids such as caprylic  

E-print Network

ANTIBODY PURIFICATION USING CAPRYLIC ACID In mildly acidic conditions, the addition of short-chain fatty acids such as caprylic acid to serum will precipitate most serum proteins with the exception or ammonium sulfate precipitation, caprylic acid will yield a relatively pure antibody preparation. 1. Measure

Mecham, Robert

41

X-ray photoelectron spectroscopic study of surface chemistry of dibenzyl disulfide on steel under mild and severe wear conditions  

NASA Technical Reports Server (NTRS)

X-ray photoelectron spectroscopy was used to characterize the chemical composition of 304 stainless steel surfaces run in oil containing dibenzyl disulfide under both mild and severe wear conditions. In severe wear a sulfide was formed at the expense of the normal oxide. This was due to either chemical attack on the oxide or reaction with clean metal exposed by the wear process. In the mild wear scars there was no evidence of either sulfide or mercaptide. The oxide, however, was approximately twice as thick as the normal oxide on an unworn surface. The change in surface chemistry was primarily a function of wear rate rather than load.

Wheeler, D. R.

1978-01-01

42

Mild pre-heating of organic cation-exchanged clays enhances their interactions with nitrobenzene in aqueous environment  

Microsoft Academic Search

Aqueous sorption kinetics and equilibrium isotherms of nitrobenzene were studied on two series of sorbents that were prepared\\u000a by (i) replacing inorganic exchangeable cations in Wyoming bentonite with tetraethylammonium (TEA) and benzyltrimethylammonium\\u000a (BTMA) and (ii) heating synthesized complexes in air at different temperatures (between 150 and 420°C). The aim of this work\\u000a was to examine recently observed enhancement of aqueous

Mikhail Borisover; Nadezhda Bukhanovsky; Isaak Lapides; Shmuel Yariv

2010-01-01

43

Formation of flavor components by the reaction of amino acid and carbonyl compounds in mild conditions.  

PubMed

This work describe products of reactions between four alpha-dicarbonyl compounds (diacetyl, pentan-2,3-dione, glyoxal, and methylglyoxal) or two alpha-hydroxy ketones, (acetoine and acetol) and amino acids present in wines. The results shows the formation of odorous products or strong-smelling additives resulting from the Maillard and Strecker reaction in a primarily aqueous medium, at low temperature and low pH ( approximately pH 3.5) of the wine. GC/FID, GC/FPD, GC/NPD and GC/MS techniques were used. The olfactive characteristics of the products are described. In the presence of sulfur amino acids and in particular cysteine, many products were formed with a heterocycle production such as pyrazines and methylpyrazines, methylthiazoles, acetylthiazoles, acetylthiazolines, acetylthiazolidines, trimethyloxazole, and dimethylethyloxazoles. These various compounds present odors of sulfur, cornlike, pungent, nut, popcorn, roasted hazelnut, toasted, roasted, and ripe fruits. The chemical conditions of the model reactions are specified. The influence of temperature and pH on the reactions in the presence of cysteine were also studied. PMID:10995267

Pripis-Nicolau, L; de Revel, G; Bertrand, A; Maujean, A

2000-09-01

44

Controlled copper-mediated chlorination of phenol rings under mild conditions.  

PubMed

The very unusual case of copper-mediated chlorination of phenol rings under mild conditions at room temperature is reported. Reaction of the ligand 1,7-bis(2-hydroxyphenyl)-2,6-diaza-4-hydroxylheptane (H3L1) with CuCl2 in acetonitrile leads to either the formation of a tetranuclear copper(II) complex [Cu4(HL3)2(mu-Cl)2Cl2](CH3CN) (1) or a linear trinuclear complex [Cu3(HL1)2Cl2(CH3CN)2](CH3CN)2 (2), depending on the reaction conditions. Both compounds have been fully characterized, including the determination of their 3D structures by X-ray diffraction. The unprecedented tetranuclear compound 1 is constituted of a dichlorido-bridged dimer of di-mu-phenoxido-dinuclear species, whereas the trinuclear complex 2 presents a linear array of copper(II) ions, held together through di-mu-phenoxido bridges of the central and external ions. The magnetic susceptibility of the two compounds was investigated, revealing either very strong (J<-500 cm-1) or strong (J value around -370(1) cm-1) antiferromagnetic dominant interactions among the CuII ions for 1 and 2, respectively. The tetranuclear complex 1 is obtained, under dry conditions, through the in situ formation of ligand HL3 (H3L3=1,7-bis(2-hydroxy-5-chlorophenyl)-2,6-diaza-4-hydroxylheptane) by oxidative chlorination of (HL1)2-. In the presence of traces of water, 1 is partially hydroxylated at the ortho position of one of the phenyl rings. The use of trimethylorthoformate as the dehydrating agent prevents the formation of hydroxylated ligands. Several partly chlorinated/hydroxylated products (identified as H3L2) have also been obtained through slight variations of the synthetic procedures (presence or absence of water and/or triethylamine in the reaction mixtures). These partially chlorinated and/or hydroxylated coordination species are mutually isomorphous to either 1 or 2. Several "modified" ligands have been isolated and characterized by 1H NMR and MS, after reaction with sodium sulfide of the complexes formed. PMID:17497851

Song, Yu-Fei; van Albada, Gerard A; Tang, Jinkui; Mutikainen, Ilpo; Turpeinen, Urho; Massera, Chiara; Roubeau, Olivier; Costa, José Sanchez; Gamez, Patrick; Reedijk, Jan

2007-06-11

45

Incidence of Postconcussion Symptoms in Psychiatric Diagnostic Groups, Mild Traumatic Brain Injury, and Comorbid Conditions  

Microsoft Academic Search

The constellation of physical, cognitive, and emotional symptoms, collectively known as postconcussion syndrome (PCS), is not uniquely associated with concussion, making the etiology of chronic postconcussion symptoms controversial. The current study compared percentages of individuals meeting symptom-based criteria for PCS in a population-based sample of veterans composed of subgroups with various psychiatric diagnoses, a history of mild traumatic brain injury

Alison J. Donnell; Michelle S. Kim; Marc A. Silva; Rodney D. Vanderploeg

2012-01-01

46

Denaturation and partial renaturation of a tightly tetramerized DsRed protein under mildly acidic conditions  

E-print Network

Denaturation and partial renaturation of a tightly tetramerized DsRed protein under mildly acidic by denaturation followed by partial renaturation of the protein. Further, analytical ultracen- trifugation by Elsevier Science B.V. All rights reserved. Key words: Red £uorescent protein; pH dependence; Denaturation

Verkhusha, Vladislav V.

47

Assessment and Diagnosis of Mild Traumatic Brain Injury, Posttraumatic Stress Disorder, and Other Polytrauma Conditions: Burden of Adversity Hypothesis  

Microsoft Academic Search

Objective\\/Method: Military personnel returning from Iraq and Afghanistan have been exposed to physical and emotional trauma. Challenges related to assessment and intervention for those with posttraumatic stress disorder (PTSD) and\\/or history of mild traumatic brain injury (TBI) with sequelae are discussed, with an emphasis on complicating factors if conditions are co-occurring. Existing literature regarding cumulative disadvantage is offered as a

Lisa A. Brenner; Rodney D. Vanderploeg; Heidi Terrio

2009-01-01

48

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

PubMed

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. PMID:25116442

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

2014-09-17

49

Oxygen Tension in the Aqueous Humor of Human Eyes under Different Oxygenation Conditions  

PubMed Central

Purpose To measure oxygen tension in the aqueous humor of human eyes under different oxygenation conditions. Methods This prospective comparative interventional case series consisted of two parts. In the first part, 120 consecutive patients scheduled for cataract surgery were randomized into group I (control group) in which surgery was performed under local anesthesia inhaling 21% oxygen; group II in whom general anesthesia using 50% oxygen was employed; and group III receiving general anesthesia with 100% oxygen. After aspirating 0.2 ml aqueous humor under sterile conditions, the aqueous sample and a simultaneously drawn arterial blood sample were immediately analyzed using a blood gas analyzer. In part II the same procedures were performed in 10 patients after fitting a contact lens and patching the eye for 20 minutes (group IV) and in 10 patients after transcorneal delivery of oxygen at a flow rate of 5 L/min (group V). Results Mean aqueous PO2 in groups I, II and III was 112.3±6.2, 141.1±20.4, and 170.1±27 mmHg, respectively (P values <0.001) and mean arterial PO2 was 85.7±7.9, 184.6±46, and379.1±75.9 mmHg, respectively (P values <0.001). Aqueous PO2 was 77.2±9.2 mmHg in group IV and 152.3±10.9 mmHg in group V (P values <0.001). There was a significant correlation between aqueous and blood PO2 (r=0.537, P<0.001). The contribution of atmospheric oxygen to aqueous PO2 was 23.7%. Conclusion Aqueous oxygen tension is mostly dependent on the systemic circulation and in part on the atmosphere. Increasing inspiratory oxygen and transcorneal oxygen delivery both increase aqueous PO2 levels. PMID:23943686

Sharifipour, Farideh; Idani, Esmaeil; Zamani, Mitra; Helmi, Toktam; Cheraghian, Bahman

2013-01-01

50

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

PubMed

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

Pastore, Carlo; Lopez, Antonio; Mascolo, Giuseppe

2014-03-01

51

Surface grafting of poly(ethylene glycol) onto poly(acrylamide-co-vinyl amine) cross-linked films under mild conditions.  

PubMed

Poly(ethylene glycol) (PEG) was grafted onto poly(acrylamide-co-vinyl amine) (poly(AM-co-VA)) film using tresylated PEG (TPEG) at 37 degrees C in aqueous buffers (pH 7.4) with a view to surface-modifying microencapsulated mammalian cells. Poly(AM-co-VA) film was synthesized by Hofmann degradation of a cross-linked poly(acrylamide) film. Conversion to vinyl amine on the surface of the film was approximately 50%, but bulk conversion was not observed; surface specificity was thought to be the result of cleavage of aminated polymer chains at the surface due to chain scission. Reaction between primary amine and TPEG gave a graft yield of 2 mol% (based on XPS) with respect to available surface amine groups, equivalent to 54 mol% ethylene oxide based on monomer units. Physical adsorption of non-activated polymer was done under identical conditions as a control and the difference in oxygen content was significant compared to TPEG. The type of buffer agent and buffer concentration did not influence graft yields. This graft reaction, which was completed in as little as 2 h was considered to be mild enough to be used for a surface modification of microcapsules containing cells without affecting their viability. Such a surface modification technique may prove to be a useful means of enhancing the biocompatibility of microcapsules (or any tissue engineering construct) even after cell encapsulation or seeding. PMID:9648025

Yamamoto, Y; Sefton, M V

1998-01-01

52

Synthesis of graphene-based Pt nanoparticles by a one-step in situ plasma approach under mild conditions  

SciTech Connect

Herein, a one-step in situ plasma approach to synthesize the highly dispersed Pt nanoparticles on graphene under mild conditions is reported. The graphene oxide (GO) was transformed into graphene and H{sub 2}PtCl{sub 6} was simultaneously transformed into Pt nanoparticles under argon plasma conditions. The synthesized graphene-based Pt nanoparticles were characterized by scanning electron microscopy, atomic force microscopy, x-ray diffraction, and Fourier transform infrared spectroscopy. The analysis showed that the Pt nanoparticles were deposited on graphene as a form of face-centered cubical structure and the oxygen groups on graphene oxide were partially removed. The results of x-ray photoelectron spectroscopy analysis further confirmed the results.

Wang Qi; Song Mingming; Chen Changlun; Wei Yu; Zuo Xiao; Wang Xiangke [Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China)

2012-07-16

53

A New Class of Single-Component Absorbents for Reversible Carbon Dioxide Capture under Mild Conditions.  

PubMed

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. PMID:25410150

Barzagli, Francesco; Lai, Sarah; Mani, Fabrizio

2014-11-19

54

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

DOEpatents

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.

Giese, R.W.; Wang, P.

1996-04-30

55

A New Biarylphosphine Ligand for the Pd-Catalyzed Synthesis of Diaryl Ethers under Mild Conditions  

E-print Network

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 ...

Salvi, Luca

56

Effects of Mass Transfer and Flow Conditions on SRB Corrosion of Mild Steel  

Microsoft Academic Search

Microbiologically Influenced Corrosion (MIC) is a growing problem in the oil and gas industry resulting in huge financial losses. Sulfate Reducing Bacteria (SRB) are often the culprits although many other microorganisms can also be directly or indirectly involved. From the bioprocess engineering angle, mass transfer and flow conditions are very important in SRB biofilm formation and MIC corrosion rates. Experiments

Tingyue Gu; Srdjan Nesic; Jie Wen; Kaili Zhao

2006-01-01

57

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

PubMed

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. PMID:23926242

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

2013-10-01

58

Rapid and effective oxidative pretreatment of woody biomass at mild reaction conditions and low oxidant loadings  

PubMed Central

Background One route for producing cellulosic biofuels is by the fermentation of lignocellulose-derived sugars generated from a pretreatment that can be effectively coupled with an enzymatic hydrolysis of the plant cell wall. While woody biomass exhibits a number of positive agronomic and logistical attributes, these feedstocks are significantly more recalcitrant to chemical pretreatments than herbaceous feedstocks, requiring higher chemical and energy inputs to achieve high sugar yields from enzymatic hydrolysis. We previously discovered that alkaline hydrogen peroxide (AHP) pretreatment catalyzed by copper(II) 2,2?-bipyridine complexes significantly improves subsequent enzymatic glucose and xylose release from hybrid poplar heartwood and sapwood relative to uncatalyzed AHP pretreatment at modest reaction conditions (room temperature and atmospheric pressure). In the present work, the reaction conditions for this catalyzed AHP pretreatment were investigated in more detail with the aim of better characterizing the relationship between pretreatment conditions and subsequent enzymatic sugar release. Results We found that for a wide range of pretreatment conditions, the catalyzed pretreatment resulted in significantly higher glucose and xylose enzymatic hydrolysis yields (as high as 80% for both glucose and xylose) relative to uncatalyzed pretreatment (up to 40% for glucose and 50% for xylose). We identified that the extent of improvement in glucan and xylan yield using this catalyzed pretreatment approach was a function of pretreatment conditions that included H2O2 loading on biomass, catalyst concentration, solids concentration, and pretreatment duration. Based on these results, several important improvements in pretreatment and hydrolysis conditions were identified that may have a positive economic impact for a process employing a catalyzed oxidative pretreatment. These improvements include identifying that: (1) substantially lower H2O2 loadings can be used that may result in up to a 50-65% decrease in H2O2 application (from 100 mg H2O2/g biomass to 35–50 mg/g) with only minor losses in glucose and xylose yield, (2) a 60% decrease in the catalyst concentration from 5.0 mM to 2.0 mM (corresponding to a catalyst loading of 25 ?mol/g biomass to 10 ?mol/g biomass) can be achieved without a subsequent loss in glucose yield, (3) an order of magnitude improvement in the time required for pretreatment (minutes versus hours or days) can be realized using the catalyzed pretreatment approach, and (4) enzyme dosage can be reduced to less than 30 mg protein/g glucan and potentially further with only minor losses in glucose and xylose yields. In addition, we established that the reaction rate is improved in both catalyzed and uncatalyzed AHP pretreatment by increased solids concentrations. Conclusions This work explored the relationship between reaction conditions impacting a catalyzed oxidative pretreatment of woody biomass and identified that significant decreases in the H2O2, catalyst, and enzyme loading on the biomass as well as decreases in the pretreatment time could be realized with only minor losses in the subsequent sugar released enzymatically. Together these changes would have positive implications for the economics of a process based on this pretreatment approach. PMID:23971902

2013-01-01

59

Highly efficient C-H hydroxylation of carbonyl compounds with oxygen under mild conditions.  

PubMed

A transition-metal-free Cs2 CO3 -catalyzed ?-hydroxylation of carbonyl compounds with O2 as the oxygen source is described. This reaction provides an efficient approach to tertiary ?-hydroxycarbonyl compounds, which are highly valued chemicals and widely used in the chemical and pharmaceutical industry. The simple conditions and the use of molecular oxygen as both the oxidant and the oxygen source make this protocol very environmentally friendly and practical. This transformation is highly efficient and highly selective for tertiary C(sp(3) )?H bond cleavage. PMID:24281892

Liang, Yu-Feng; Jiao, Ning

2014-01-01

60

Hydrolysis of dilute acid-pretreated cellulose under mild hydrothermal conditions.  

PubMed

The hydrolysis of dilute acid-pretreated cellulose was investigated in a conventional oven and under microwave heating. Two acids--sulfuric and oxalic--were studied. For both hydrothermal conditions (oven and microwave) the resultant total organic carbon (TOC) values obtained by the hydrolysis of the cellulose pretreated with sulfuric acid were higher than those obtained by the hydrolysis of the cellulose pretreated with oxalic acid. However, the dicarboxylic acid exhibited higher hydrolytic efficiency towards glucose. The hydrolysis of cellulose was greatly promoted by microwave heating. The Rietveld method was applied to fit the X-ray patterns of the resultant cellulose after hydrolysis. Oxalic acid preferentially removed the amorphous region of the cellulose and left the crystalline region untouched. On the other hand, sulfuric acid treatment decreased the ordering of the cellulose by partially disrupting its crystalline structure. PMID:25037336

Chimentão, R J; Lorente, E; Gispert-Guirado, F; Medina, F; López, F

2014-10-13

61

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

PubMed

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. PMID:17605134

Herrmann, Andreas

2007-01-01

62

Solvothermal synthesis of perovskites and pyrochlores: crystallisation of functional oxides under mild conditions.  

PubMed

In this critical review we consider the large literature that has accumulated in the past 5-10 years concerning solution-mediated crystallisation of complex oxide materials using hydrothermal, or more generally solvothermal, reaction conditions. The aim is to show how the synthesis of dense, mixed-metal oxide materials, usually prepared using the high temperatures associated with solid-chemistry, is perfectly feasible from solution in one step reactions, typically at temperatures as low as 200 °C, and that important families of oxide materials have now been reported to crystallise using such synthetic approaches. We will focus on two common structures seen in oxide chemistry, ABO(3) perovskites and A(2)B(2)O(6)O' pyrochlores, and include a systematic survey of the variety of chemical elements now included in these two prototypical structure types, from transition metals, in families of materials that include titanates, niobates, manganites and ferrites, to main-group elements in stannates, plumbates and bismuthates. The significant advantages of solution-mediated crystallisation are well illustrated by the recent literature: examples are provided of elegant control of crystal form from the nanometre to the micron length scale to give thin films, anisotropic crystal morphologies, or hierarchical structures of materials with properties desirable for many important contemporary applications. In addition, new metastable materials have been reported, not stable once high temperatures and pressures are applied and hence not amenable using conventional synthesis. We critically discuss the possible control offered by solvothermal synthesis from crystal chemistry to crystal form and how the discovery of new materials may be achieved. Computer simulation, combinatorial synthesis approaches and in situ methods to follow crystallisation will be vital in providing the predictability in synthesis that is needed for rational design of new materials (232 references). PMID:20532260

Modeshia, Deena R; Walton, Richard I

2010-11-01

63

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

PubMed

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). PMID:25479067

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

2014-12-23

64

Solubility of platinum in aqueous solutions at 25C and pHs 4 to 10 under oxidizing conditions  

E-print Network

Solubility of platinum in aqueous solutions at 25°C and pHs 4 to 10 under oxidizing conditions to those found in such environments. The solubility of platinum metal was measured at 25°C in several strength of the aqueous solutions did not exceed 0.30 (molal scale). The interpretation of the solubility

Boyer, Edmond

65

Impact of imposed anaerobic conditions and microbial activity on aqueous-phase solubility of polycyclic aromatic hydrocarbons from soil.  

PubMed

The influence of anaerobic conditions on aqueous-phase polycyclic aromatic hydrocarbon (PAH) bioavailability was investigated in laboratory microcosms. Highly aged (>70 years), PAH-contaminated soil was incubated under anaerobic conditions by using various anaerobic headspaces, anaerobic headspaces with an oxygen-scavenging complex (titanium(III) citrate) in the aqueous phase, or anaerobic headspaces with electron-acceptor amendments in the aqueous phase. Incubation of soil solely under anaerobic conditions resulted in increased aqueous concentrations of all PAHs tested (fluoranthene, pyrene, benz[a]anthracene, and benzo[a]pyrene). Benz[a]anthracene and benzo[a]pyrene extractable concentrations were above aqueous solubility, by as much as an order of magnitude for the latter. The degree of solubility increase observed was a function of molecular weight of the PAH regardless of initial soil concentration, suggesting formation of stable PAH-soluble organic matter associations. The soil samples incubated aerobically for 90 d before imposition of anaerobic conditions did not release PAHs to the aqueous phase. Methanogenic organisms and sulfate-reducing bacteria were seen to have the most significant effect on increases in aqueous-phase PAHs. Polycyclic aromatic hydrocarbons made more soluble under anaerobic conditions was available to be degraded or transformed under aerobic conditions. PMID:15719987

Pravecek, Tasha L; Christman, Russell F; Pfaender, Frederic K

2005-02-01

66

Palladium-pyridyl catalytic films: A highly active and recyclable catalyst for hydrogenation of styrene under mild conditions.  

PubMed

Palladium-pyridyl catalytic films, (PdCl2/bpy)n, were created by alternating immersions of a substrate in PdCl2 and bpy (bpy=4, 4'-bipyridyl) solutions. The as-prepared (PdCl2/bpy)10 catalyst demonstrated a remarkable catalytic activity toward hydrogenation of styrene under mild conditions and the turnover frequency (TOF) is as high as 6944h(-1). Pd(II) ions of (PdCl2/bpy)n films are in situ reduced to Pd nanoparticles (NPs) during the hydrogenation of styrene process, which results in the catalytic activity of the films. The results of X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) further demonstrate that Pd(II) ions of (PdCl2/bpy)n films were gradually converted to Pd(0) states. The catalytic activity is related to bilayer numbers and the activity increases with the number of bilayers below 10 bilayers. The solid substrates coated with (PdCl2/bpy)n multilayer catalysts were easily removed from the reaction mixture without separation filtration. Moreover, (PdCl2/bpy)n catalysts were reused for 10 consecutive reactions without loss of activity. The present (PdCl2/bpy)n heterogeneous catalysts have the advantages of easy separation and good recyclability. PMID:25490567

Gao, Shuiying; Li, Weijin; Cao, Rong

2015-03-01

67

Aryl-copper(III)-acetylides as key intermediates in Csp2-Csp model couplings under mild conditions.  

PubMed

The mechanism of copper-mediated Sonogashira couplings (so-called Stephens-Castro and Miura couplings) is not well understood and lacks clear comprehension. In this work, the reactivity of a well-defined aryl-Cu(III) species (1ClO4) with p-R-phenylacetylenes (R = NO2, CF3, H) is reported and it is found that facile reductive elimination from a putative aryl-Cu(III)-acetylide species occurs at room temperature to afford the Caryl-Csp coupling species (IR), which in turn undergo an intramolecular reorganisation to afford final heterocyclic products containing 2H-isoindole (P?NO2, P?CF3, PHa) or 1,2-dihydroisoquinoline (PHb) substructures. Density Functional Theory (DFT) studies support the postulated reductive elimination pathway that leads to the formation of C?sp2-Csp bonds and provide the clue to understand the divergent intramolecular reorganisation when p-H-phenylacetylene is used. Mechanistic insights and the very mild experimental conditions to effect Caryl-Csp coupling in these model systems provide important insights for developing milder copper-catalysed Caryl-Csp coupling reactions with standard substrates in the future. PMID:25042813

Rovira, Mireia; Font, Marc; Acuña-Parés, Ferran; Parella, Teodor; Luis, Josep M; Lloret-Fillol, Julio; Ribas, Xavi

2014-08-01

68

Silica Sulfuric Acid\\/Wet SiO2 as a Novel Heterogeneous System for Cleavage of Carbon Nitrogen Double Bonds Under Mild Conditions  

Microsoft Academic Search

Silica sulfuric acid in the presence of wet SiO2 was caused to react with oximes, hydrazones, semicarbazones, azines, and Schiff-bases. It was observed that it converts them to their corresponding carbonyl compounds in good to excellent yields under mild and heterogeneous conditions.

Mohammad Ali Zolfigol; Iraj Mohammad Poor-Baltork; Bibi Fatemeh Mirjalili; Farhad Shirini; Sadegh Salehzadeh; Hassan Keypour; Arash Ghorbani-Choghamarani; Mohammad Hassan Zebarjadian; Kamal Mohammadi; Azizeh Hazar

2003-01-01

69

Theoretical study of the dimerization of calcium carbonate in aqueous solution under natural water conditions  

NASA Astrophysics Data System (ADS)

First principles calculations have been used to investigate the condensation reactions of hydrated calcium bicarbonate monomers in a simulated aqueous environment. The reaction pathway for the calcium bicarbonate dimerization process has been computed at the density functional theory-PBE level with the COSMO dielectric continuum model to simulate the hydrated environment. The results indicate that calcium bicarbonate dimers form via an associative mechanism: the first step involves a sevenfold calcium bicarbonate intermediate followed by the loss of one water molecule from the first coordination shell of calcium. Both steps are characterised by a low energy barrier of approximately 2 kcal mol -1, suggesting that the dimerization process is not kinetically hindered in aqueous solution. However, the Gibbs free energies for the condensation reactions to form the calcium bicarbonate dimers and the species Ca(HCO 3) 2(H 2O) 4, Ca(HCO 3) 3(H 2O) 3- and Ca 2(HCO 3)(H 2O) 103+, computed using the PBE and mPW1B95 density functional theory levels for the gas-phase component and the UAHF-CPCM solvation model for the hydration contribution, are all positive, which indicates that the formation of these early calcium bicarbonate clusters is thermodynamically unfavourable in aqueous solutions. Our calculations therefore suggest that the oligomerization of calcium carbonate is not spontaneous in water, at the conditions considered in our simulations, i.e. T = 298 K and neutral pH, which indicates that the nucleation of calcium carbonate cannot occur through a homogeneous process when calcium-bicarbonate ion pairs are the major source of CaCO 3 in the aqueous environment.

Di Tommaso, Devis; de Leeuw, Nora H.

2009-09-01

70

CO? carbonation under aqueous conditions using petroleum coke combustion fly ash.  

PubMed

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. PMID:25000300

González, A; Moreno, N; Navia, R

2014-12-01

71

A 5' Leader of Rbm3, a Cold Stress-induced mRNA, Mediates Internal Initiation of Translation with Increased Efficiency under Conditions of Mild Hypothermia.  

PubMed

Although mild hypothermia generally reduces protein synthesis in mammalian cells, the expression of a small number of proteins, including Rbm3, is induced under these conditions. In this study, we identify an Rbm3 mRNA with a complex 5' leader sequence containing multiple upstream open reading frames. Although these are potentially inhibitory to translation, monocistronic reporter mRNAs containing this leader were translated relatively efficiently. In addition, when tested in the intercistronic region of dicistronic mRNAs, this leader dramatically enhanced second cistron translation, both in transfected cells and in cell-free lysates, suggesting that the Rbm3 leader mediates cap-independent translation via an internal ribosome entry site (IRES). Inasmuch as Rbm3 mRNA and protein levels are both increased in cells exposed to mild hypothermia, the activity of this IRES was evaluated at a cooler temperature. Compared to 37 degrees C, IRES activity at 33 degrees C was enhanced up to 5-fold depending on the cell line. Moderate enhancements also occurred with constructs containing other viral and cellular IRESes. These effects of mild hypothermia on translation were not caused by decreased cell growth, as similar effects were not observed when cells were serum starved. The results suggest that cap-independent mechanisms may facilitate the translation of particular mRNAs during mild hypothermia. PMID:11470798

Chappell, S A; Owens, G C; Mauro, V P

2001-10-01

72

Semiconducting Polymer Encapsulated Mesoporous Silica Particles with Conjugated Europium Complexes: Toward Enhanced Luminescence under Aqueous Conditions.  

PubMed

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 ?-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 (?Ln = 39%) and longer lifetime (?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. PMID:25289897

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

2014-11-12

73

Structure of a Novel Enzyme That Catalyzes Acyl Transfer to Alcohols in Aqueous Conditions  

SciTech Connect

The unusual architecture of the enzyme (MsAcT) isolated from Mycobacterium smegmatis forms the mechanistic basis for favoring alcoholysis over hydrolysis in water. Unlike hydrolases that perform alcoholysis only under anhydrous conditions, MsAcT demonstrates alcoholysis in substantially aqueous media and, in the presence of hydrogen peroxide, has a perhydrolysis:hydrolysis ratio 50-fold greater than that of the best lipase tested. The crystal structures of the apoenzyme and an inhibitor-bound form have been determined to 1.5 {angstrom} resolution. MsAcT is an octamer in the asymmetric unit and forms a tightly associated aggregate in solution. Relative to other structurally similar monomers, MsAcT contains several insertions that contribute to the oligomerization and greatly restrict the shape of the active site, thereby limiting its accessibility. These properties create an environment by which MsAcT can catalyze transesterification reactions in an aqueous medium and suggests how a serine hydrolase can be engineered to be an efficient acyltransferase.

Mathews, I.; Soltis, M.; Saldajeno, M.; Ganshaw, G.; Sala, R.; Weyler, W.; Cervin, M.A.; Whited, G.; Bott, R.

2009-06-03

74

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

SciTech Connect

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)

Yaohiro Inagaki; Toshitaka Imamura; Kazuya Idemitsu; Tatsumi Arima [Kyushu University, Fukuoka, 819-0395 (Japan); Osamu Kato [Kobe Steel Inc., Kobe, 657-0845 (Japan); Hidekazu Asano; Tsutomu Nishimura [RWMC, Tokyo, 105-0001 (Japan)

2007-07-01

75

The behaviour of an old catalyst revisited in a wet environment: Co ions in APO-5 split water under mild conditions.  

PubMed

Samples of the activated microporous aluminophosphate Co-APO-5, featuring ca. 20% of Co(3+) cations, when immersed in water evolve molecular oxygen at room temperature in an endothermic process, without the need for either light or a sacrificial reactant. Successive drying of the sample at temperatures around 520 K releases molecular hydrogen, with recovery of the initial conditions. Several hydration-dehydration cycles may be performed without loss of activity, i.e. water is split in a thermal cycle under relatively mild conditions. PMID:24615513

Bonelli, Barbara; Armandi, Marco; Hernandez, Simelys; Vankova, Svetoslava; Celasco, Edvige; Tomatis, Maura; Saracco, Guido; Garrone, Edoardo

2014-04-21

76

Oxidative degradation of organic pollutants in aqueous solution using zero valent copper under aerobic atmosphere condition.  

PubMed

Oxidative degradation of organic pollutants and its mechanism were investigated in aqueous solution using zero valent copper (ZVC) under aerobic atmosphere condition. Diethyl phthalate (DEP) was completely oxidized after 120 min reaction by ZVC at initial pH 2.5 open to the air. DEP degradation followed the pseudo-first-order kinetics after the lag period, and the degradation rate of DEP increased gradually with the increase of ZVC dosage, and the decrease of initial pH from 5.8 to 2.0. ZVC required a shorter induction time and exhibited persistent oxidation capacity compared to that of zero valent iron and zero valent aluminium. The mechanism investigation showed that remarkable amount of Cu(+)/Cu(2+) and H2O2 were formed in ZVC acidic system, which was due to the corrosive dissolution of ZVC and the concurrent reduction of oxygen. The addition of tert-butanol completely inhibited the degradation of DEP and the addition of Fe(2+) greatly enhanced the degradation rate, which demonstrated that hydroxyl radical was mainly responsible for the degradation of DEP in ZVC acidic system under aerobic atmosphere condition, and the formation of hydroxyl radical was attributed to the Fenton-like reaction of in situ formed Cu(+) with H2O2. PMID:24857902

Wen, Gang; Wang, Sheng-Jun; Ma, Jun; Huang, Ting-Lin; Liu, Zheng-Qian; Zhao, Lei; Xu, Jin-Lan

2014-06-30

77

Dynamic nuclear polarization of 13C in aqueous solutions under ambient conditions  

NASA Astrophysics Data System (ADS)

The direct enhancement of the 13C NMR signal of small molecules in solution through Overhauser-mediated dynamic nuclear polarization (DNP) has the potential to enable studies of systems where enhanced signal is needed but the current dissolution DNP approach is not suitable, for instance if the sample does not tolerate a freeze-thaw process or if continuous flow or rapid re-polarization of the molecules is desired. We present systematic studies of the 13C DNP enhancement of 13C-labeled small molecules in aqueous solution under ambient conditions, where we observe both dipolar and scalar-mediated enhancement. We show the role of the three-spin effects from enhanced protons on 13C DNP through DNP experiments with and without broadband 1H decoupling and by comparing DNP results with H 2O and D 2O. We conclude that the efficiency of 13C Overhauser DNP in small molecules strongly depends on the distance of closest approach between the electron and 13C nucleus, the presence of a scalar contribution to the coupling factor, and the magnitude of the three-spin effect due to adjacent polarized protons. The enhancement appears to depend less on the translational dynamics of the 13C-labeled small molecules and radicals.

Lingwood, Mark D.; Han, Songi

2009-12-01

78

Diverse Aqueous Conditions on Mars from New Orbital Detections of Carbonate and Sulfate  

NASA Astrophysics Data System (ADS)

Diverse aqueous environments on ancient Mars have been a key inference from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on NASA's Mars Reconnaissance Orbiter, which has identified many alteration minerals in a range of settings [e.g., 1-4]. Here we report two new minerals detected using CRISM. In the southern highlands northwest of the Hellas basin, a mid-sized crater exposes carbonate in its central uplift. Spectral absorptions at 1, 2.33, and 2.53 microns are most consistent with Fe-carbonate, distinct from the Mg-carbonates identified from orbit by [5]. Fe-carbonate is associated with Mg-phyllosilicate in fractured materials formerly buried kilometers beneath the surface, and--like the Mg/Fe-carbonate found by the Spirit rover [6]--suggests a reducing, neutral-to-alkaline alteration environment. One of the largest phyllosilicate exposures on Mars occurs in the Mawrth Vallis region [e.g., 7]. We identify bassanite (Ca-sulfate hemihydrate) in layers underlying the phyllosilicate-bearing beds [8], a stratigraphy distinct from that predicted by global models of martian aqueous history [9]. Bassanite could have formed via acid-sulfate alteration of Ca-carbonate, through dehydration of gypsum, or under hydrothermal conditions [10]. These detections expand the known mineralogic diversity of Mars and the range of environments to explore for past habitability. [1] Mustard, J. F. et al. (2008) Nature 454, 305-309. [2] Murchie, S. L. et al. (2009) J. Geophys. Res. 114, E00D06. [3] Ehlmann, B. L. et al. (2009) J. Geophys. Res. 114, E00D08. [4] Wray, J. J. et al. (2009) Geology 37, 1043-1046. [5] Ehlmann, B. L. et al. (2008) Science 322, 1828-1832. [6] Morris, R. V. et al. Science, in press, doi:10.1126/science.1189667. [7] Poulet, F. et al. (2005) Nature 438, 623-627. [8] Wray, J. J. et al. Icarus, in press, doi:10.1016/j.icarus.2010.06.001. [9] Bibring, J.-P. et al. (2006) Science 312, 400-404. [10] Vaniman, D. T. et al. (2009) LPSC 40, 1654.

Wray, James J.; Squyres, S. W.

2010-10-01

79

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

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, ?, 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.

Schaef, Herbert T.; McGrail, B. Peter

2009-05-01

80

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...

81

Mild Salt Stress Conditions Induce Different Responses in Root Hydraulic Conductivity of Phaseolus vulgaris Over-Time  

PubMed Central

Plants respond to salinity by altering their physiological parameters in order to maintain their water balance. The reduction in root hydraulic conductivity is one of the first responses of plants to the presence of salt in order to minimize water stress. Although its regulation has been commonly attributed to aquaporins activity, osmotic adjustment and the toxic effect of Na+ and Cl? have also a main role in the whole process. We studied the effects of 30 mM NaCl on Phaseolus vulgaris plants after 9 days and found different responses in root hydraulic conductivity over-time. An initial and final reduction of root hydraulic conductivity, stomatal conductance, and leaf water potential in response to NaCl was attributed to an initial osmotic shock after 1 day of treatment, and to the initial symptoms of salt accumulation within the plant tissues after 9 days of treatment. After 6 days of NaCl treatment, the increase in root hydraulic conductivity to the levels of control plants was accompanied by an increase in root fructose content, and with the intracellular localization of root plasma membrane aquaporins (PIP) to cortex cells close to the epidermis and to cells surrounding xylem vessels. Thus, the different responses of bean plants to mild salt stress over time may be connected with root fructose accumulation, and intracellular localization of PIP aquaporins. PMID:24595059

Calvo-Polanco, Monica; Sánchez-Romera, Beatriz; Aroca, Ricardo

2014-01-01

82

Highly Chemoselective Reduction of Amides (Primary, Secondary, Tertiary) to Alcohols using SmI2/Amine/H2O under Mild Conditions  

PubMed Central

Highly chemoselective direct reduction of primary, secondary, and tertiary amides to alcohols using SmI2/amine/H2O is reported. The reaction proceeds with C–N bond cleavage in the carbinolamine intermediate, shows excellent functional group tolerance, and delivers the alcohol products in very high yields. The expected C–O cleavage products are not formed under the reaction conditions. The observed reactivity is opposite to the electrophilicity of polar carbonyl groups resulting from the nX ? ?*C=O (X = O, N) conjugation. Mechanistic studies suggest that coordination of Sm to the carbonyl and then to Lewis basic nitrogen in the tetrahedral intermediate facilitate electron transfer and control the selectivity of the C–N/C–O cleavage. Notably, the method provides direct access to acyl-type radicals from unactivated amides under mild electron transfer conditions. PMID:24460078

2014-01-01

83

Highly chemoselective reduction of amides (primary, secondary, tertiary) to alcohols using SmI2/amine/H2O under mild conditions.  

PubMed

Highly chemoselective direct reduction of primary, secondary, and tertiary amides to alcohols using SmI2/amine/H2O is reported. The reaction proceeds with C-N bond cleavage in the carbinolamine intermediate, shows excellent functional group tolerance, and delivers the alcohol products in very high yields. The expected C-O cleavage products are not formed under the reaction conditions. The observed reactivity is opposite to the electrophilicity of polar carbonyl groups resulting from the n(X) ? ?*(C?O) (X = O, N) conjugation. Mechanistic studies suggest that coordination of Sm to the carbonyl and then to Lewis basic nitrogen in the tetrahedral intermediate facilitate electron transfer and control the selectivity of the C-N/C-O cleavage. Notably, the method provides direct access to acyl-type radicals from unactivated amides under mild electron transfer conditions. PMID:24460078

Szostak, Michal; Spain, Malcolm; Eberhart, Andrew J; Procter, David J

2014-02-12

84

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

PubMed Central

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

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

2014-01-01

85

Asian dust particles converted into aqueous droplets under remote marine atmospheric conditions  

PubMed Central

The chemical history of dust particles in the atmosphere is crucial for assessing their impact on both the Earth’s climate and ecosystem. So far, a number of studies have shown that, in the vicinity of strong anthropogenic emission sources, Ca-rich dust particles can be converted into aqueous droplets mainly by the reaction with gaseous HNO3 to form Ca(NO3)2. Here we show that other similar processes have the potential to be activated under typical remote marine atmospheric conditions. Based on field measurements at several sites in East Asia and thermodynamic predictions, we examined the possibility for the formation of two highly soluble calcium salts, Ca(NO3)2 and CaCl2, which can deliquesce at low relative humidity. According to the results, the conversion of insoluble CaCO3 to Ca(NO3)2 tends to be dominated over urban and industrialized areas of the Asian continent, where the concentrations of HNO3 exceed those of HCl ([HNO3/HCl] >  ? 1). In this regime, CaCl2 is hardly detected from dust particles. However, the generation of CaCl2 becomes detectable around the Japan Islands, where the concentrations of HCl are much higher than those of HNO3 ([HNO3/HCl] <  ? 0.3). We suggest that elevated concentrations of HCl in the remote marine boundary layer are sufficient to modify Ca-rich particles in dust storms and can play a more important role in forming a deliquescent layer on the particle surfaces as they are transported toward remote ocean regions. PMID:20921372

Tobo, Yutaka; Zhang, Daizhou; Matsuki, Atsushi; Iwasaka, Yasunobu

2010-01-01

86

Enzyme mediated silicon-oxygen bond formation; the use of Rhizopus oryzae lipase, lysozyme and phytase under mild conditions.  

PubMed

The potential for expanding the variety of enzymic methods for siloxane bond formation is explored. Three enzymes, Rhizopus oryzae lipase (ROL), lysozyme and phytase are reported to catalyse the condensation of the model compound, trimethylsilanol, formed in situ from trimethylethoxysilane, to produce hexamethyldisiloxane in aqueous media at 25 °C and pH 7. Thermal denaturation and reactant inhibition experiments were conducted to better understand the catalytic role of these enzyme candidates. It was found that enzyme activities were significantly reduced following thermal treatment, suggesting a potential key-role of the enzyme active sites in the catalysis. Similarly, residue-specific modification of the key-amino acids believed to participate in the ROL catalysis also had a significant effect on the silicon bio-catalysis, indicating that the catalytic triad of the lipase may be involved during the enzyme-mediated formation of the silicon-oxygen bond. E. coli phytase was found to be particularly effective at catalysing the condensation of trimethylsilanol in a predominantly organic medium consisting of 95% acetonitrile and 5% water. Whereas the use of enzymes in silicon chemistry is still very much a developing and frontier activity, the results presented herein give some grounds for optimism that the variety of enzyme mediated reactions will continue to increase and may one day become a routine element in the portfolio of the synthetic silicon chemist. PMID:20683529

Abbate, Vincenzo; Bassindale, Alan R; Brandstadt, Kurt F; Lawson, Rachel; Taylor, Peter G

2010-10-21

87

Transdermal drug delivery using microemulsion and aqueous systems: influence of skin storage conditions on the in vitro permeability of diclofenac from aqueous vehicle systems.  

PubMed

The objective of this study was to evaluate the transdermal delivery potential of diclofenac-containing microemulsion system in vivo and in vitro. It was found that the transdermal administration of the microemulsion to rats resulted in 8-fold higher drug plasma levels than those obtained after application of Voltaren Emulgel. After s.c. administration (3.5 mg/kg), the plasma levels of diclofenac reached a peak of 0.94 microg/ml at t=1 h and decreased rapidly to 0.19 microg/ml at t=6 h, while transdermal administration of the drug in microemulsion maintained constant levels of 0.7-0.9 microg/ml for at least 8 h. The transdermal fluxes of diclofenac were measured in vitro using skin excised from different animal species. In three rodent species, penetration fluxes of 53.35+/-8.19 (furry mouse), 31.70+/-3.83 (hairless mouse), 31.66+/-4.45 (rat), and 22.89+/-6.23 microg/cm(2)/h (hairless guinea pig) were obtained following the application of the microemulsion. These fluxes were significantly higher than those obtained by application of the drug in aqueous solution. In contrast to these results, a 'flip-flop' phenomenon was observed when frozen porcine skin (but not fresh skin) was significantly more permeable to diclofenac-in-water than to the drug-in-microemulsion. In fact, the drug penetration from the microemulsion was not affected by the skin storage conditions, but it was increased when an aqueous solution was applied. However, this unusual phenomenon observed in non-freshly used porcine skin places a question mark on its relevancy for in vitro penetration studies involving aqueous vehicle systems. PMID:16431047

Sintov, Amnon C; Botner, Shafir

2006-03-27

88

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

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

Ruch, Susanne; Irrgang, Torsten; Kempe, Rhett

2014-10-01

89

Findings of electroencephalographic brain mapping in mild to moderate dementia of the Alzheimer type during resting, motor, and music-perception conditions.  

PubMed

Sixteen-channel electroencephalographic (EEG) brain mapping studies were carried out under resting conditions in 41 patients with mild to moderate dementia of the Alzheimer type, diagnosed according to DSM-III-R criteria. The patients showed diffuse patterns of EEG slowing, as known from the literature. They showed increases of theta power in large bilateral brain areas and bitemporal increases of delta power as compared with both age-matched and younger control subjects. In addition, the patients had increased beta activity in comparison with the younger control group, but not with the age-matched control subjects. Functional brain mapping revealed decreases of EEG power during manual-motor and music-perception tasks in delta frequencies for patients, which was not seen in either of the two control groups. All frequency bands revealed major gender-related differences in EEG activity, which should receive more attention in future research. PMID:8272452

Günther, W; Giunta, R; Klages, U; Haag, C; Steinberg, R; Satzger, W; Jonitz, L; Engel, R

1993-10-01

90

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

SciTech Connect

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.

Gao Lizhen [School of Mechanical Engineering M050, University of Western Australia, 35 Stirling Highway, Crawley WA 6009 (Australia)]. E-mail: lizhen@mech.uwa.edu.au; Wang Xiaolin [School of Mechanical Engineering M050, University of Western Australia, 35 Stirling Highway, Crawley WA 6009 (Australia); Chua, H.T. [School of Mechanical Engineering M050, University of Western Australia, 35 Stirling Highway, Crawley WA 6009 (Australia); Kawi, Sibudjing [Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576 (Singapore)

2006-07-15

91

Nitrosation of Phenolic Substrates under Mildly Basic Conditions: Selective Preparation of p-Quinone Monooximes and Their Antiviral Activities.  

PubMed

Nitrosation of 3-methoxyphenol and 1-naphthol were examined under both acidic (NaNO(2)-EtCO(2)H-H(2)O) and basic (i-AmNO(2)-K(2)CO(3)-DMF) conditions. Acidic nitrosations afforded ortho-directed products, whereas para-directed nitrosations were observed under basic conditions to yield p-quinone monooximes. The basic para-directed nitrosation was further examined using 15 phenols, two naphthols, and four phenolic heterocyclics. A one-pot operation of the basic nitrosation followed by methylation with dimethyl sulfate gave the corresponding methyl ethers in high yield. Two p-quinone monooximes derived from 3-methoxyphenol and 8-hydroxyquinoline showed a moderate activity against HSV-1, and the latter oxime was also effective against HSV-2. On the other hand, p-quinone monooximes derived from methyl salicylate, 1-naphthol, 7-hydroxy-2-methylbenzo[b]furan, and 8-hydroxycoumarin showed the comparable activity to that of DDI against HIV-1. PMID:11667112

Ishikawa, Tsutomu; Watanabe, Toshiko; Tanigawa, Hisashi; Saito, Tatsuru; Kotake, Ken-Ichiro; Ohashi, Yoshiaki; Ishii, Hisashi

1996-04-19

92

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

SciTech Connect

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.

Rard, J.A.

1989-10-01

93

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

PubMed Central

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

2011-01-01

94

Amino acid/KI as multi-functional synergistic catalysts for cyclic carbonate synthesis from CO2 under mild reaction conditions: a DFT corroborated study.  

PubMed

Naturally occurring amino acids were identified as efficient co-catalysts for the alkali metal halide-mediated synthesis of cyclic carbonates from carbon dioxide and epoxides under mild, solvent free reaction conditions. The binary system of histidine/potassium iodide gave an appreciable turnover number of 535 for propylene oxide in 3 h. Detailed studies evaluating a variety of amino acids revealed that the basic amino acids afforded better conversion rates. The formation of a seven membered ring involving the zwitterionic ends of the amino acid, the metal halide, and the epoxide was considered to accelerate the catalysis rate. Density functional theory calculations were performed for the first time on amino acid co-catalyzed cycloaddition to provide further evidence for this hypothesis. The iodide ions of the alkali metal halide displayed excellent synergism with the hydrogen bonding groups of the amino acids in the production of cyclic carbonates, whereas bromide and chloride anions functioned less efficiently. The utilization of amino acids to enhance the catalytic activity of the cheap and eco-friendly alkali metal halides for cyclic carbonate synthesis represents a cost-effective, greener route towards the chemical fixation of carbon dioxide. PMID:24270098

Roshan, Kuruppathparambil Roshith; Kathalikkattil, Amal Cherian; Tharun, Jose; Kim, Dong Woo; Won, Yong Sun; Park, Dae Won

2014-02-01

95

Fe(ClO 4 ) 3 · 6H 2 O: a mild and efficient catalyst for one-pot three component synthesis of ? -acetamido carbonyl compounds under solvent-free conditions  

Microsoft Academic Search

A one-pot multi-component reaction for the synthesis of ?-acetamido carbonyl compounds is reported. The reaction uses a variety of aldehydes, acetophenone derivatives or methyl acetoacetate,\\u000a acetonitrile, and acetyl chloride in the presence of ferric perchlorate, a mild, efficient and inexpensive catalyst effective\\u000a under solvent free conditions.

Majid M. Heravi; Farahnaz K. Behbahani; Mansoureh Daraie; Hossein A. Oskooie

2009-01-01

96

Diffusion behavior of lysozyme in aqueous ammonium sulfate solutions under varying solution conditions as determined by dynamic light scattering  

SciTech Connect

As proteins gain significance in commercial applications such as pharmaceuticals, detergents, organic waste management and cosmetics, efficient and economical recovery of these valuable biomolecules is of increasing importance. the salting-out process has found widespread application in the area of protein separations. To date, salt-induced precipitation of proteins from complex aqueous solutions remains largely an empirical process; no comprehensive model exists to predict salting-out phase equilibria in protein solutions. Rational predictive models for salt-induced precipitation will therefore be of great value in protein purification, both on the preparative and the analytical scale. Any attempt to model theoretically salt-induced protein precipitation must include the known physics of protein interactions in aqueous solution. With this in mind, it is crucial to acknowledge that protein precipitation is fundamentally an aggregation process. In order to incorporate aggregation effects into ongoing efforts to model salting out of proteins, it is necessary to quantify the degree of aggregation as a function of solution conditions. Therefore, dynamic light scattering measurements were performed with a well-studied protein, hen-egg-white lysozyme, under several solution conditions.

Fornefeld, U.M.; Kuehner, D.E.; Blanch, H.W.; Prausnitz, J.M. (Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering Lawrence Berkeley Lab., CA (United States). Chemical Sciences Div.)

1994-12-01

97

Oxidation of 1,4-dichloro-2-butene by aqueous sodium hypochlorite under phase transfer conditions  

SciTech Connect

In the industrial process for the production of chloroprene from butadiene, the problem of reducing the organic impurities in the waste water to 2000 mg/liter has not yet been solved. A method has been patented for the oxidation of organic compounds by sodium hypochlorite at high temperatures and high pressure but this method is limited by the oxidation of soluble organic compounds. The oxidation of 1,4-dichloro-2-butene by aqueous sodium hypochlorite was studied. A sharp increase in the reaction rate was found in the presence of phase transfer catalysts and surfactants. The involvement of oxygen as a cooxiant and the effect of surfactants on the absorption of atmospheric oxygen by the reaction system were demonstrated.

Grigoryan, G.S.; Karoyan, I.L.; Malkhasyan, A.Ts.; Martirosyan, G.T.; Artamkina, G.A.; Beletskaya, I.P.

1987-11-10

98

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

PubMed

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. PMID:17456420

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

2007-05-15

99

Photochemical processing of aldrin and dieldrin in frozen aqueous solutions under arctic field conditions.  

PubMed

Organochlorine (OC) contaminants are transported to the Polar Regions, where they have the potential to bioaccumulate, presenting a threat to the health of wildlife and indigenous communities. They deposit onto snowpack during winter, and accumulate until spring, when they experience prolonged solar irradiation until snowmelt occurs. Photochemical degradation rates for aldrin and dieldrin, in frozen aqueous solution made from MilliQ water, 500 ?M hydrogen peroxide solution or locally-collected melted snow were measured in a field campaign near Barrow, AK, during spring-summer 2008. Significant photoprocessing of both pesticides occurs; the reactions depend on temperature, depth within the snowpack and whether the predominant phase is ice or liquid water. The effect of species present in natural snowpack is comparable to 500 ?M hydrogen peroxide, pointing to the potential significance of snowpack-mediated reactions. Aldrin samples frozen at near 0 °C were more reactive than comparable liquid samples, implying that the microenvironments experienced on frozen ice surfaces are an important consideration. PMID:21396757

Rowland, Glenn A; Bausch, Alexandra R; Grannas, Amanda M

2011-05-01

100

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

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. PMID:25468707

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

2015-01-01

101

Common Clinical Conditions – Age, Low BMI, Ritonavir Use, Mild Renal Impairment - Affect Tenofovir Pharmacokinetics in a Large Cohort of HIV-Infected Women  

PubMed Central

Objective Tenofovir is used commonly in HIV treatment and prevention settings, but factors that correlate with tenofovir exposure in real-world setting are unknown. Design Intensive pharmacokinetic (PK) studies of tenofovir in a large, diverse cohort of HIV-infected women over 24-hours at steady-state were performed and factors that influenced exposure (assessed by areas-under-the-time-concentration curves, AUCs) identified Methods HIV-infected women (n=101) on tenofovir-based therapy underwent intensive 24-hour PK sampling. Data on race/ethnicity, age, exogenous steroid use, menstrual cycle phase, concomitant medications, recreational drugs and/or tobacco, hepatic and renal function, weight and body mass index (BMI) were collected. Multivariable models using forward stepwise selection identified factors associated with effects on AUC. Glomerular filtration rates (GFR) prior to starting tenofovir were estimated by the CKD-EPI equation using both creatinine and cystatin-C measures Results The median (range) of tenofovir AUCs was 3350 (1031–13,911) ng x h/mL. Higher AUCs were associated with concomitant ritonavir use (1.33-fold increase, p 0.002), increasing age (1.21-fold increase per decade, p=0.0007) and decreasing BMI (1.04-fold increase per 10% decrease in BMI). When GFR was calculated using cystatin-C measures, mild renal insufficiency prior to tenofovir initiation was associated with higher subsequent exposure (1.35-fold increase when pre-tenofovir GFR <70mL/min, p=0.0075). Conclusions Concomitant ritonavir use, increasing age, decreasing BMI and lower GFR prior to tenofovir initiation as estimated by cystatin C were all associated with elevated tenofovir exposure in a diverse cohort of HIV-infected women. Clinicians treating HIV-infected women should be aware of common clinical conditions that affect tenofovir exposure when prescribing this medication. PMID:24275255

BAXI, Sanjiv M.; GREENBLATT, Ruth M.; BACCHETTI, Peter; SCHERZER, Rebecca; MINKOFF, Howard; HUANG, Yong; ANASTOS, Kathryn; COHEN, Mardge; GANGE, Stephen J.; YOUNG, Mary; SHLIPAK, Michael G.; GANDHI, Monica

2014-01-01

102

Mild traumatic brain injury.  

PubMed

Mild traumatic brain injury (mTBI) can have a profoundly negative effect on the injured person's quality of life, producing cognitive, physical, and psychological symptoms; impeding postinjury family reintegration; creating psychological distress among family members; and often having deleterious effects on spousal and parental relationships. This article reviews the most commonly reported signs and symptoms of mTBI, explores the condition's effects on both patient and family, and provides direction for developing nursing interventions that promote patient and family adjustment. PMID:25319524

Hyatt, Kyong S

2014-11-01

103

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

USGS Publications Warehouse

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.

Bassett, W.A.; Anderson, A.J.; Mayanovic, R.A.; Chou, I.-M.

2000-01-01

104

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...

105

X-ray photoelectron spectroscopic study of surface chemistry of dibenzyl-disulfide on steel under mild and severe wear conditions  

NASA Technical Reports Server (NTRS)

Wear tests were performed on 304 stainless steel lubricated with pure mineral oil with and without dibenzyl-disulfide. Both mild and severe wear were observed. The type of wear was distinguished by a marked change in wear rate, friction coefficient, and wear scar appearance. The chemical composition of the wear scar surface was examined with X-ray photoelectron spectroscopy in conjunction with argon ion sputter etching. In severe wear scars, a sulfide was formed at the expense of the normal oxide layer. In mild wear scars, there were only superficial sulfur compounds, but there was a substantial increase in the oxide thickness.

Wheeler, D. R.

1977-01-01

106

Inhibitory Effect of Berberis vulgaris Aqueous Extract on Acquisition and Reinstatement Effects of Morphine in Conditioned Place Preferences (CPP) in Mice  

PubMed Central

Background: It has been elucidated that Berberis vulgaris (barberry) can alleviate morphine withdrawal syndrome. Also it has been reported that aqueous extract of barberry possibly have inhibitory effect on NMDA receptors. Objectives: In this study, we decided to evaluate the effects of aqueous extract of B. vulgaris fruit on morphine tendency in mice using conditioned place preference (CPP) method. Materials and Methods: In experiment 1 (acquisition phase), mice underwent morphine-induced conditioned place preference (CPP) training with injections of morphine (40 mg/kg). In experiment 2 (extinction and reinstatement phases), mice underwent the same CPP training as in experiment 1 and subsequent extinction training on day 16th a reinstatement by CPP was done by injection of reminding 10 mg/kg morphine. Results: The administration of morphine (40 mg/kg for four days) produced place preference. In the first method, the aqueous extract of barberry (200 mg/kg) prevented morphine tendency to white cell in CPP method. In the second method, after inter-peritoneal injection of aqueous extracts of barberry at 100 and 200 mg/kg, the animals tendency toward the white cells of CPP chamber on the sixteenth day (after a reminder injection of morphine 10 mg/kg) was significantly reduced. Conclusions: These results show that aqueous extract of barberry can reduce the acquisition and reinstatement of morphine-induced conditioned place preference. PMID:25237645

Imenshahidi, Mohsen; Qaredashi, Reza; Hashemzaei, Mahmoud; Hosseinzadeh, Hossein

2014-01-01

107

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

NASA Astrophysics Data System (ADS)

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.

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

2009-08-01

108

In situ Raman study and thermodynamic model of aqueous carbonate speciation in equilibrium with aragonite under subduction zone conditions  

NASA Astrophysics Data System (ADS)

Carbonate minerals may be recycled into the mantle at subduction zones. However, the evolution of carbonate minerals in equilibrium with aqueous fluids as well as the nature of the chemical species of dissolved carbon in the deep crust and mantle at high PT conditions are still unknown. In this study, we report an integrated experimental and theoretical study of the equilibration of CaCO3 minerals with pure water at subduction zone conditions over the pressure and temperature ranges 5-80 kbar and 300-400 °C. The fluid speciation was studied using in situ Raman spectroscopy. The relative amounts of dissolved carbonate and bicarbonate were estimated from the corrected areas of the Raman bands of the carbonate and bicarbonate ions and used to constrain a theoretical thermodynamic model of the fluid speciation and solubility of aragonite. At 300-400 °C, our results indicate that the proportion of dissolved C present as CO2 strongly decreases in fluids in equilibrium with aragonite at P > 10 kbar. CO2 is replaced by HCO3- and CaHCO3+ which predominate until P > 40 kbar, where CO32- and CaCO30 become the dominant C-species. At higher temperatures, the theoretical model indicates that CO2 again becomes a major species in fluids in equilibrium with aragonite depending on the pressure.

Facq, Sébastien; Daniel, Isabelle; Montagnac, Gilles; Cardon, Hervé; Sverjensky, Dimitri A.

2014-05-01

109

Corrosion phenomena on alloy 625 in aqueous solutions containing hydrochloric acid and oxygen under subcritical and supercritical conditions  

SciTech Connect

Supercritical Water Oxidation (SCWO) is a very effective process to destroy hazardous aqueous wastes containing organic contaminants. The main target applications in the USA are the destruction of DOD and DOE wastes such as rocket fuels and explosives, warfare agents and organics present in low level radioactive liquid wastes. Alloy 625 is frequently used as reactor material for Supercritical Water Oxidation (SCWO) applications. This is due to the favorable combination of mechanical properties, corrosion resistance, price and availability. Nevertheless, the corrosion of alloy 625 like the corrosion of other Ni-base alloys during oxidation of hazardous organic waste containing chloride proceeds too fast and is a major problem in SCWO applications. In these experiments high pressure, high-temperature resistant tube reactors made of alloy 625 were used as specimens. They were exposed to SCWO conditions, without organics, at temperatures up to 500 C and pressures up to 37 MPa for up to 150 h. Simultaneously, coupons also made from alloy 625 are exposed inside the test tubes. The most important corrosion problem for alloy 625 is pitting and intercrystalline corrosion at temperatures near the critical temperature, i.e. in the preheater and cooling sections of the test tubes. Under certain conditions, stress corrosion cracking appears and leads to premature failure of the test reactors. The corrosion products were insoluble in supercritical water and formed thick layers in the supercritical part of the reactor. Under these layers only minor corrosion occurred. 33 refs.

Boukis, N.; Kritzer, P. [Forschungszentrum Karlsruhe (Germany)

1997-08-01

110

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

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

111

Diffusion and polymerization of styrene in an aqueous solution of potassium persulfate under static conditions  

SciTech Connect

The potassium persulfate-initiated polymerization of styrene in a mechanically agitated mixture of water and monomer leads to the formation of a stable, monodisperse latex. In order to explain the mechanism of the stabilization of the latex particles in this system, the authors present a detailed investigation of the polymerization of styrene in a specially constructed electrochemical cell under static conditions. A schematic of the cell is shown. Results show that the capacity of the electrical double layer on the platinum electrode remains constant with time in a system containing only a solution of electrolyte, either K/sub 2/SO/sub 4/ or K/sub 2/S/sub 2/O/sub 8/.

Oganesyan, A.A.; Boyadzhyan, V.G.; Gritskova, I.A.; Gukasyan, A.V.; Matsoyan, S.G.; Pravednikov, A.N.

1985-10-01

112

Solubility of aqueous methane under metastable conditions: implications for gas hydrate nucleation.  

PubMed

To understand the prenucleation stage of methane hydrate formation, we measured methane solubility under metastable conditions using molecular dynamics simulations. Three factors that influence solubility are considered: temperature, pressure, and the strength of the modeled van der Waals attraction between methane and water. Moreover, the naturally formed water cages and methane clusters in the methane solutions are analyzed. We find that both lowering the temperature and increasing the pressure increase methane solubility, but lowering the temperature is more effective than increasing the pressure in promoting hydrate nucleation because the former induces more water cages to form while the latter makes them less prevalent. With an increase in methane solubility, the chance of forming large methane clusters increases, with the distribution of cluster sizes being exponential. The critical solubility, beyond which the metastable solutions spontaneously form hydrate, is estimated to be ~0.05 mole fraction in this work, corresponding to the concentration of 1.7 methane molecules/nm(3). This value agrees well with the cage adsorption hypothesis of hydrate nucleation. PMID:23639139

Guo, Guang-Jun; Rodger, P Mark

2013-05-30

113

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

USGS Publications Warehouse

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.

Mayanovic, R.A.; Anderson, A.J.; Bassett, W.A.; Chou, I.-M.

1999-01-01

114

Weathering and dissolution rates among Pb shot pellets of differing elemental compositions exposed to various aqueous and soil conditions.  

PubMed

The present study was performed to investigate the weathering and dissolution rates of Pb shot pellets differing in elemental composition (Pb, Sb, and As) exposed under various aqueous and soil conditions using five commercial shot pellet preparations. Upon immersion in distilled water, the dissolution rates of shot pellets, calculated from the difference in weight before versus after immersion, decreased with increasing Sb + As contents and the dominant precipitate was hydrocerussite. These subsidiary ingredients may be related to the difficulty of metallic Pb oxidation (transformation to PbO). Weight losses standardized by the amount of rainfall upon exposure to rainfall on open grassland and under canopies of Japanese cedar (Cryptomeria japonica) and bamboo-leafed oak (Quercus myrsinaefolia) were 1.11, 1.07, and 7.35 mg g pellets(-1) year(-1) L(-1), respectively, and was also related to Sb + As contents in shot pellets. However, annual dissolution rates of Pb standardized by the amount of rainfall as the soluble fraction at the same sites were 0.72, 0.33, and 0.40 mg Pb g pellets(-1) year(-1) L(-1) in the same order. These trends seemed to be related to the rainfall pH, which induces precipitation of Pb dissolved as PbCO(3) under conditions of higher pH at the Q. myrsinaefolia site or organic matter released from leaves, etc., which can form metal complexes. Dissolution rates of shot pellets buried in soils (Cambisol, Fluvisol, Regosol, Andosol) also seemed to be related to the soil pH and dissolved organic matter contents but were about sixfold faster than those with exposure to rainfall. PMID:20039167

Takamatsu, Takejiro; Murata, Tomoyoshi; Koshikawa, Masami K; Watanabe, Mirai

2010-07-01

115

Peptide synthesis in aqueous environments: the role of extreme conditions and pyrite mineral surfaces on formation and hydrolysis of peptides.  

PubMed

A comprehensive study of free energy landscapes and mechanisms of COS-mediated polymerization of glycine via N-carboxy anhydrides (NCAs, "Leuchs anhydrides") and peptide hydrolysis at the water-pyrite interface at extreme thermodynamic conditions is presented. Particular emphasis is set on the catalytic effects of the mineral surface including the putative role of the ubiquitous sulfur vacancy defects. It is found that the mere presence of a surface is able to change the free energetics of the elementary reaction steps. This effect can be understood in terms of a reduction of entropic contributions to the reactant state by immobilizing the reactants and/or screening them from bulk water in a purely geometric ("steric") sense. Additionally, the pyrite directly participates chemically in some of the reaction steps, thus changing the reaction mechanism qualitatively compared to the situation in bulk water. First, the adsorption of reactants on the surface can preform a product-like structure due to immobilizing and scaffolding them appropriately. Second, pyrite can act as a proton acceptor, thus replacing water in this role. Third, sulfur vacancies are found to increase the reactivity of the surface. The finding that the presence of pyrite speeds up the rate-determining step in the formation of peptides with respect to the situation in bulk solvent while stabilizing the produced peptide against hydrolysis is of particular interest to the hypothesis of prebiotic peptide formation at hydrothermal aqueous conditions. Apart from these implications, the generality of the studied organic reactions are of immediate relevance to many fields such as (bio)geochemistry, biomineralization, and environmental chemistry. PMID:21561111

Schreiner, Eduard; Nair, Nisanth N; Wittekindt, Carsten; Marx, Dominik

2011-06-01

116

Steady-state ?-radiolysis of aqueous methyl ethyl ketone (2-butanone) under postulated nuclear reactor accident conditions  

Microsoft Academic Search

The steady-state ?-radiolysis of aqueous solutions containing 1×10?3 mol dm?3 methyl ethyl ketone (MEK) has been studied at a dose rate of 0.12 Gy s?1, 25°C and an initial pH of 10. Experiments were conducted in air-, Ar- or N2O-purged aqueous solutions, or in Ar-purged solutions with added tert-butanol. MEK, its radiolytic products, and the change in pH resulting from

P. Driver; G. Glowa; J. C. Wren

2000-01-01

117

Influence of processing and curing conditions on beads coated with an aqueous dispersion of cellulose acetate phthalate.  

PubMed

The influence of fluidized-bed processing conditions, as well as curing parameters with and without humidity, on drug release from beads coated with cellulose acetate phthalate (CAP) aqueous dispersion was investigated. Theophylline beads prepared by extrusion-spheronization were coated with diethyl phthalate (DEP)-plasticized CAP dispersion (Aquacoat CPD) using a Strea-1 fluidized-bed coater. The parameters investigated were plasticizer level, outlet temperature, spray rate during coating application and fluidizing air velocities using a half-factorial design. The processing temperature during coating applications was identified as a critical factor among the variables investigated. The release rate significantly decreased when the beads were coated at 36 degrees C compared to those coated at 48 degrees C (P<0.01). Higher coating efficiencies and better coalescence of films were obtained at the lower coating temperature. Above the minimum film-formation temperature (MFFT), drug release in acid decreased as the coating temperature was decreased. Curing at 60 degrees C significantly reduced the drug release for beads coated at 32 degrees C, but had no significant effect on drug release for beads coated at temperatures above 36 degrees C. Curing at 50 degrees C in an atmosphere containing 75% RH (relative humidity), irreversibly converted poor film formation into better coalescence, and increased the mechanical toughness of films. Subsequent removal of the moisture absorbed from beads did not significantly alter the enteric profiles obtained through heat-humidity curing. The extent of coalescence via heat-humidity curing was dependent on the curing temperature, % humidity, curing time and coating temperature. The results demonstrated the importance of the selection of coating temperature for CAP-coated beads and the role of moisture on CAP film formation. Curing with humidity was found to be more effective than without. PMID:10799816

Williams, R O; Liu, J

2000-05-01

118

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

PubMed

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, ?, 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. PMID:25031185

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

2014-09-01

119

Efficient Solid-Phase Synthesis of 3-Substituted-5-Oxo-5H-Thiazolo[2,3-b]Quinazoline-8-Carboxamide under Mild Conditions with Two Diversity Positions  

PubMed Central

Highly efficient solid-phase synthesis of thiazolo[2,3,b]quinazolines under mild conditions was developed using resin-bound 2-amino-terephthalamic acid, Fmoc-NCS, and bromoketones. Primary amines immobilized to an acid-cleavable backbone amide linker were acylated with 1-methyl-2-aminoterephtalate. Following cleavage of the methyl ester, Fmoc-NCS was used to form a resin-bound thiourea. Bromoketones were subsequently added to form an aminothiazole ring and the cyclization was performed using DIC/HOBt to afford thiazolo[2,3,b]quinazolines. Highly efficient solid-phase synthesis is amenable to high throughput/combinatorial synthesis. PMID:17907790

Bouillon, Isabelle; Krch?ák, Viktor

2008-01-01

120

Caustic Stress Corrosion Cracking of Mild Steel  

Microsoft Academic Search

The stress corrosion cracking (SCC) behavior of cold worked mild steel in hot, aqueous, 33 pct NaOH solutions was studied\\u000a with prefatigue cracked double cantilever beam specimens. SCC kinetics were studied under freely corroding potentials (E\\u000a corr ? ?1.00 VSHE) and potentiostatic potentials of ?0.76 VSHE near the active-passive transition. The pH of the liquid within the crack was determined

Douglas Singbeil; Desmond Tromans

1982-01-01

121

Modeling Mild Collisions  

NASA Astrophysics Data System (ADS)

It is a surprisingly common phenomenon that two objects collide with each other and emerge only mildly altered. We motivate a dynamic-independent, analytical framework to study these mild collisions through two specific examples: (1) Head-on collision between two non-integrable solitons, and (2) Gravitational self-interaction for a collapsing shell of radiation.

Yang, I.-Sheng

2015-01-01

122

Relationship of fatigue-crack growth rate in an aqueous corrosive medium to the electrochemical conditions at the crack tip  

Microsoft Academic Search

p of this data with the fatiguecrack growth rate in samples of 40Kh13 steel in an aqueous solution with pH 8 was studied. The electrochemical investigations and cyclic crack resistance tests were made on i0  20  150 mm beam samples of rectangular cross section of 40Kh13 steel, the chemical composition, heat-treat cycles, and mechanical properties of which were

V. V. Panasyuk; L. V. Ratych; I. N. Dmytrakh

1984-01-01

123

Mild Cognitive Impairment Research  

MedlinePLUS Videos and Cool Tools

... Media Text Size Videos and Media Virtual Library Brain Tour Facts & Figures Spotlight on Researchers Web Links ... early diagnosis Mild Cognitive Impairment Research Inside the brain Genetics in Alzheimer's Advances in brain imaging Diet ...

124

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

USGS Publications Warehouse

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.

Mayanovic, R.A.; Jayanetti, S.; Anderson, A.J.; Bassett, W.A.; Chou, I.-M.

2003-01-01

125

Kinetics of OH-initiated oxidation of some oxygenated organic compounds in the aqueous phase under tropospheric conditions  

NASA Astrophysics Data System (ADS)

The interest for multiphase interactions of Volatile Organic Compounds (VOCs) in the troposphere has increased for a few years. Inside the clouds water droplets, soluble VOCs can be oxidized by free radicals thus modifying the droplet composition. This reactivity has an impact on the tropospheric oxidizing capacity as well as the aerosols' properties. In the present work, we measured aqueous phase OH-initiated oxidation rate constants of several oxygenated organic compounds relevant to the atmosphere or chosen as test compounds (ethanol, t-butanol, 1-butanol, iso-propanol, 1-propanol, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, phenol, ethyl ter-butyl ether (ETBE), n-propyl acetate, acetone, methyl ethyl ketone (MEK), methyl iso-butyl ketone (MIBK), ethyl formate). Experiments took place in an aqueous phase photoreactor. The rate constants were determinated using the relative kinetic method. Different OH-radical sources were tested, as well as different reference compounds in order to detect any artifact. The results have shown validation of the experimental protocol on test compounds. The overall results allowed to propose a structure reactivity method in order to predict OH-oxidation rate constant of new compounds. Finally, tropospheric life times of the studied compounds were compared inside and outside a cloud.

Poulain, L.; Grubert, S.; François, S.; Monod, A.; Wortham, H.

2003-04-01

126

Unprecedented one-pot sequential thiolate substitutions under mild conditions leading to a red emissive BODIPY dye 3,5,8-tris(PhS)-BODIPY.  

PubMed

The simple reaction of phenylthiol with 8-MeS-BODIPY (1) in dichloromethane was readily accomplished to form 8-PhS-BODIPY (2). If the reaction is performed in THF 3,8-bis(phenylthio)-BODIPY (3) and 3,5,8-tris(phenylthio)-BODIPY (4) are sequentially formed in an unprecedented reaction. This provides a simple new methodology for the introduction of the phenylthio-moiety in the 3- and 5-positions. Alkyl thiols do not form multi-thiolated products under identical conditions, as exemplified using EtSH, where only 8-EtS-BODIPY (5) is formed. PMID:25429697

Roacho, Robinson I; Metta-Magaña, Alejandro; Peña-Cabrera, Eduardo; Pannell, Keith

2015-01-28

127

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

PubMed Central

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

2014-01-01

128

Corrosion phenomena of alloy 625 in aqueous solutions containing sulfuric acid and oxygen under subcritical and supercritical conditions  

SciTech Connect

Corrosion phenomena of alloy 625 pressure tubes were investigated in aqueous solutions containing up to 0.2 mol/kg sulfuric acid and up to 1.44 mol/kg oxygen. Applied maximum temperatures and pressures were 500 C, and 38 MPa, respectively. Corrosion started at temperatures around 150 C with intergranular attack. Above 250 C, the whole surface of the alloy was attacked, shallow pits and deep intergranular attack appeared. This behavior can be explained by transpassive dissolution of the protecting Cr(III) oxide layer and leads to severe material loss. The upper temperature limit of severe corrosion at an experimental pressure of 24 MPa was about 390 C. As temperature was increased further and the density of the solution dropped to low values, only slight corrosion was detected.

Kritzer, P.; Boukis, N.; Dinjus, E. [Forschungszentrum Karlsruhe (Germany)

1998-12-31

129

Mild cognitive impairment and mild dementia: a clinical perspective.  

PubMed

Mild cognitive impairment and mild dementia are common problems in the elderly. Primary care physicians are the first point of contact for most patients with these disorders and should be familiar with their diagnosis, prognosis, and management. Both mild cognitive impairment and mild dementia are characterized by objective evidence of cognitive impairment. The main distinctions between mild cognitive impairment and mild dementia are that in the latter, more than one cognitive domain is invariably involved and substantial interference with daily life is evident. The diagnosis of mild cognitive impairment and mild dementia is based mainly on the history and cognitive examination. The prognosis for mild cognitive impairment and mild dementia is an important motivation for diagnosis because in both, there is a heightened risk for further cognitive decline. The etiology of mild cognitive impairment and mild dementia can often be established through the clinical examination, although imaging and other laboratory tests may also contribute. Although Alzheimer disease is the most common cause of both, cerebrovascular disease and Lewy body disease make important contributions. Pharmacological treatments are of modest value in mild dementia due to Alzheimer disease, and there are no approved pharmacological treatments for mild cognitive impairment of any etiology. Nonetheless, new-onset cognitive impairment is a worrisome symptom to patients and families that demands answers and advice. If a patient is having difficulties managing medications, finances, or transportation independently, diagnosis and intervention are necessary to ensure the health and safety of the patient. PMID:25282431

Knopman, David S; Petersen, Ronald C

2014-10-01

130

Looking for the best experimental conditions to detail the protein solvation shell in a binary aqueous solvent via small angle scattering  

NASA Astrophysics Data System (ADS)

Protein hydration features attract particular interest in different fields, from biology up to physics, crossing chemistry and medicine. Particular attention is devoted to proteins dissolved in binary aqueous mixtures, since the presence of cosolvent can induce modifications in structural and functional properties. We have recently developed a methodology to obtain a quantitative description on protein solvation shell by a set of in-solution small angle scattering experiments, simultaneously analysed by a global-fit approach. In this paper, numerical simulations of small angle scattering curves are presented to figure out the sensitivity of the technique to different experimental conditions. Simulations concern two model proteins of different molecular weights and an unique cosolvent. A reliability test is introduced in order to find the best experimental conditions to be investigated, together with the most suitable scattering probe (neutrons or X-rays).

Grazia Ortore, Maria; Sinibaldi, Raffaele; Spinozzi, Francesco; Carbini, Andrea; Carsughi, Flavio; Mariani, Paolo

2009-06-01

131

Partial complex I deficiency due to the CNS conditional ablation of Ndufa5 results in a mild chronic encephalopathy but no increase in oxidative damage.  

PubMed

Deficiencies in the complex I (CI; NADH-ubiquinone oxidoreductase) of the respiratory chain are frequent causes of mitochondrial diseases and have been associated with other neurodegenerative disorders, such as Parkinson's disease. The NADH-ubiquinone oxidoreductase 1 alpha subcomplex subunit 5 (NDUFA5) is a nuclear-encoded structural subunit of CI, located in the peripheral arm. We inactivated Ndufa5 in mice by the gene-trap methodology and found that this protein is required for embryonic survival. Therefore, we have created a conditional Ndufa5 knockout (KO) allele by introducing a rescuing Ndufa5 cDNA transgene flanked by loxP sites, which was selectively ablated in neurons by the CaMKII?-Cre. At the age of 11 months, mice with a central nervous system knockout of Ndufa5 (Ndufa5 CNS-KO) showed lethargy and loss of motor skills. In these mice cortices, the levels of NDUFA5 protein were reduced to 25% of controls. Fully assembled CI levels were also greatly reduced in cortex and CI activity in homogenates was reduced to 60% of controls. Despite the biochemical phenotype, no oxidative damage, neuronal death or gliosis were detected in the Ndufa5 CNS-KO brain at this age. These results showed that a partial defect in CI in neurons can lead to late-onset motor phenotypes without neuronal loss or oxidative damage. PMID:24154540

Peralta, Susana; Torraco, Alessandra; Wenz, Tina; Garcia, Sofia; Diaz, Francisca; Moraes, Carlos T

2014-03-15

132

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

Synchrotron X-ray spectroscopy experiments were made on the Gd(III) aqua and chloro complexes in low pH aqueous solutions at temperatures ranging from 25 to 500????C and at pressures up to 480??MPa using a hydrothermal diamond anvil cell. Analysis of fluorescence Gd L3-edge X-ray absorption fine structure (XAFS) spectra measured from a 0.006m Gd/0.16m HNO3 aqueous solution at temperatures up to 500????C and at pressures up to 260??MPa shows that the Gd-O distance of the Gd3+ aqua ion decreases steadily at a rate of ??? 0.007??A??/100????C whereas the number of coordinated H2O molecules decreases from 9.0 ?? 0.5 to 7.0 ?? 0.4. The loss of water molecules in the Gd3+ aqua ion inner hydration shell over this temperature range (a 22% reduction) is smaller than exhibited by the Yb3+ aqua ion (42% reduction) indicating that the former is significantly more stable than the later. We conjecture that the anomalous enrichment of Gd reported from measurement of REE concentrations in ocean waters may be attributed to the enhanced stability of the Gd3+ aqua ion relative to other REEs. Gd L3-edge XAFS measurements of 0.006m and 0.1m GdCl3 aqueous solutions at temperatures up to 500????C and pressures up to 480??MPa reveal that the onset of significant Gd3+-Cl- association occurs around 300????C. Partially-hydrated stepwise inner-sphere complexes most likely of the type Gd(H2O)??-nCln+3-n occur in the chloride solutions at higher temperatures, where ?? ??? 8 at 300????C decreasing slightly to an intermediate value between 7 and 8 upon approaching 500????C. This is the first direct evidence for the occurrence of partially-hydrated REE Gd (this study) and Yb [Mayanovic, R.A., Jayanetti, S., Anderson, A.J., Bassett, W.A., Chou, I-M., 2002a. The structure of Yb3+ aquo ion and chloro complexes in aqueous solutions at up to 500 ??C and 270 MPa. J. Phys. Chem. A 106, 6591-6599.] chloro complexes in hydrothermal solutions. The number of chlorides (n) of the partially-hydrated Gd(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.

Mayanovic, R.A.; Anderson, A.J.; Bassett, W.A.; Chou, I.-M.

2007-01-01

133

Adsorption of Trace Levels of Arsenic from Aqueous Solutions by Conditioned Layered Double Hydroxides: Batch and Flow  

E-print Network

calcined layered double hydroxide (LDH) adsorbents. Conditioning the adsorbent significantly reduced the dissolution observed with uncalcined and calcined LDH3. The adsorption rates and isotherms have been invariant with particle size4. The removal of As(V) on conditioned, calcined LDH adsorbents was also

Southern California, University of

134

Corrosion inhibition of mild steel by plant extract in dilute HCl medium  

Microsoft Academic Search

The inhibition effect of Zenthoxylum alatum plant extract on the corrosion of mild steel in 5% and 15% aqueous hydrochloric acid solution has been investigated by weight loss and electrochemical impedance spectroscopy (EIS). The corrosion inhibition efficiency increases on increasing plant extract concentration till 2400ppm. The effect of temperature on the corrosion behaviour of mild steel in 5% and 15%

L. R. Chauhan; G. Gunasekaran

2007-01-01

135

The secondary formation of inorganic aerosols in the droplet mode through heterogeneous aqueous reactions under haze conditions  

NASA Astrophysics Data System (ADS)

Secondary inorganic aerosols play important roles in visibility reduction and in regional haze pollution. To investigate the characteristics of size distributions of secondary sulfates and nitrates as well as their formation mechanisms under hazes, size-resolved aerosols were collected using a Micro-Orifice Uniform Deposit Impactor (MOUDI) at an urban site in Jinan, China, in all four seasons (December 2007-October 2008). In haze episodes, the secondary sulfates and nitrates primarily formed in fine particles, with elevated concentration peaks in the droplet mode (0.56-1.8 ?m). The fine sulfates and nitrates were completely neutralized by ammonia and existed in the forms of (NH4)2SO4 and NH4NO3, respectively. The secondary formation of sulfates, nitrates and ammonium (SNA) was found to be related to heterogeneous aqueous reactions and was largely dependent on the ambient humidity. With rising relative humidity, the droplet-mode SNA concentration, the ratio of droplet-mode SNA to the total SNA, the fraction of SNA in droplet-mode particles and the mass median aerodynamic diameter of SNA presented an exponential, logarithmic or linear increase. Two heavily polluted multi-day haze episodes in winter and summer were analyzed in detail. The secondary sulfates were linked to heterogeneous uptake of SO2 followed by the subsequent catalytic oxidation by oxygen together with iron and manganese in winter. The fine nitrate formation was strongly associated with the thermodynamic equilibrium among NH4NO3, gaseous HNO3 and NH3, and showed different temperature-dependences in winter and summer.

Wang, Xinfeng; Wang, Wenxing; Yang, Lingxiao; Gao, Xiaomei; Nie, Wei; Yu, Yangchun; Xu, Pengju; Zhou, Yang; Wang, Zhe

2012-12-01

136

Wettability of steel surfaces at CO{sub 2} corrosion conditions. 1: Effect of surface active compounds in aqueous and hydrocarbon media  

SciTech Connect

The wettability of carbon steel surfaces with aqueous media (distilled water, brines) and hydrocarbon media (crude oils) was studied under CO{sub 2} corrosion conditions at 75 and 80 C and 5 bar CO{sub 2} with respect to the effect of surface active compounds (inhibitors, demulsifiers) by quasi-insitu and insitu contact angle measurements in a high pressure test cell. Fatty alcohol ethoxylates, quats, amines and imidazolines influence the hydro-philic/hydrophobic properties of carbonate scales on corroding carbon steel, but inhibiting mechanisms cannot be explained by hydrophobing effects alone. The method yields easy and quick information on substance effects, specifically in case of insitu measurements in oil-in-water systems.

Schmitt, G. [Iserlohn Univ. of Applied Sciences (Germany). Lab. for Corrosion Protection; Stradmann, N. [Corp. para la Investigation de la Corrosion, Bucamaranga (Colombia)

1998-12-31

137

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

PubMed

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

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

2012-10-12

138

Physiatric Management of Mild Traumatic Brain Injury  

Microsoft Academic Search

Mild traumatic brain injury (MTBI) is a common condition, afflicting as many as 1.5 million Americans yearly. Most individuals sustain MTBI as a result of motor vehicle collisions, but it may also occur as a result of falls, physical assault or sporting accidents. Problems related to MTBI include various pain syndromes, cognitive impairments, disorders of affect, cranial nerve dysfunction, and

STEVEN FLANAGAN

1999-01-01

139

Homocystinuria: what about mild hyperhomocysteinaemia?  

PubMed Central

Hyperhomocysteinaemia is associated with an increased risk of atherosclerotic vascular disease and thromboembolism, in both men and women. A variety of conditions can lead to elevated homocysteine levels, but the relation between high levels and vascular disease is present regardless of the underlying cause. Pooled data from a large number of studies demonstrate that mild hyperhomocysteinaemia after a standard methionine load is present in 21% of young patients with coronary artery disease, in 24% of patients with cerebrovascular disease, and in 32% of patients with peripheral vascular disease. From such data an odds ratio of 13.0 (95% confidence interval 5.9 to 28.1), as an estimate of the relative risk of vascular disease at a young age, can be calculated in subjects with an abnormal response to methionine loading. Furthermore, mild hyperhomo-cysteinaemia can lead to a two- or three-fold increase in the risk of recurrent venous thrombosis. Elevated homocysteine levels can be reduced to normal in virtually all cases by simple and safe treatment with vitamin B6, folic acid, and betaine, each of which is involved in methionine metabolism. A clinically beneficial effect of such an intervention, currently under investigation, would make large-scale screening for this risk factor mandatory. Images Figure 2 PMID:8949585

van den Berg, M.; Boers, G. H.

1996-01-01

140

Properties of aqueous solutions of lithium and calcium chlorides: formulations for use in air conditioning equipment design  

Microsoft Academic Search

The dehydration of air, for air conditioning purposes, either for human comfort or for industrial processes, is done most of the times by making it contact a surface at a temperature below its dew point. In this process not only is it necessary to cool that surface continuously, but also the air is cooled beyond the temperature necessary to the

Manuel R. Conde

2004-01-01

141

Initial results from dissolution rate testing of N-Reactor spent fuel over a range of potential geologic repository aqueous conditions  

SciTech Connect

Hanford N-Reactor spent nuclear fuel (HSNF) may ultimately be placed in a geologic repository for permanent disposal. To determine whether the engineered barrier system that will be designed for emplacement of light-water-reactor (LWR) spent fuel will also suffice for HSNF, aqueous dissolution rate measurements were conducted on the HSNF. The purpose of these tests was to determine whether HSNF dissolves faster or slower than LWR spent fuel under some limited repository-relevant water chemistry conditions. The tests were conducted using a flowthrough method that allows the dissolution rate of the uranium matrix to be measured without interference by secondary precipitation reactions that would confuse interpretation of the results. Similar tests had been conducted earlier with LWR spent fuel, thereby allowing direct comparisons. Two distinct corrosion modes were observed during the course of these 12 tests. The first, Stage 1, involved no visible corrosion of the test specimen and produced no undissolved corrosion products. The second, Stage 2, resulted in both visible corrosion of the test specimen and left behind undissolved corrosion products. During Stage 1, the rate of dissolution could be readily determined because the dissolved uranium and associated fission products remained in solution where they could be quantitatively analyzed. The measured rates were much faster than has been observed for LWR spent fuel under all conditions tested to date when normalized to the exposed test specimen surface areas. Application of these results to repository conditions, however, requires some comparison of the physical conditions of the different fuels. The surface area of LWR fuel that could potentially be exposed to repository groundwater is estimated to be approximately 100 times greater than HSNF. Therefore, when compared on the basis of mass, which is more relevant to repository conditions, the HSNF and LWR spent fuel dissolve at similar rates.

Gray, W.J.; Einziger, R.E.

1998-04-01

142

Application of Zero-Valent Iron Nanoparticles for the Removal of Aqueous Zinc Ions under Various Experimental Conditions  

PubMed Central

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

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

2014-01-01

143

A Rootstock Provides Water Conservation for a Grafted Commercial Tomato (Solanum lycopersicum L.) Line in Response to Mild-Drought Conditions: A Focus on Vegetative Growth and Photosynthetic Parameters  

PubMed Central

The development of water stress resistant lines of commercial tomato by breeding or genetic engineering is possible, but will take considerable time before commercial varieties are available for production. However, grafting commercial tomato lines on drought resistant rootstock may produce drought tolerant commercial tomato lines much more rapidly. Due to changing climates and the need for commercial production of vegetables in low quality fields there is an urgent need for stress tolerant commercial lines of vegetables such as tomato. In previous observations we identified a scion root stock combination (‘BHN 602’ scion grafted onto ‘Jjak Kkung’ rootstock hereafter identified as 602/Jjak) that had a qualitative drought-tolerance phenotype when compared to the non-grafted line. Based on this initial observation, we studied photosynthesis and vegetative above-ground growth during mild-drought for the 602/Jjak compared with another scion-rootstock combination (‘BHN 602’ scion grafted onto ‘Cheong Gang’ rootstock hereafter identified as 602/Cheong) and a non-grafted control. Overall above ground vegetative growth was significantly lower for 602/Jjak in comparison to the other plant lines. Moreover, water potential reduction in response to mild drought was significantly less for 602/Jjak, yet stomatal conductance of all plant-lines were equally inhibited by mild-drought. Light saturated photosynthesis of 602/Jjak was less affected by low water potential than the other two lines as was the % reduction in mesophyll conductance. Therefore, the Jjak Kkung rootstock caused aboveground growth reduction, water conservation and increased photosynthetic tolerance of mild drought. These data show that different rootstocks can change the photosynthetic responses to drought of a high yielding, commercial tomato line. Also, this rapid discovery of one scion-rootstock combination that provided mild-drought tolerance suggests that screening more scion-rootstock combination for stress tolerance may rapidly yield commercially viable, stress tolerant lines of tomato. PMID:25531435

Nilsen, Erik T.; Freeman, Joshua; Grene, Ruth; Tokuhisa, James

2014-01-01

144

A Rootstock Provides Water Conservation for a Grafted Commercial Tomato (Solanum lycopersicum L.) Line in Response to Mild-Drought Conditions: A Focus on Vegetative Growth and Photosynthetic Parameters.  

PubMed

The development of water stress resistant lines of commercial tomato by breeding or genetic engineering is possible, but will take considerable time before commercial varieties are available for production. However, grafting commercial tomato lines on drought resistant rootstock may produce drought tolerant commercial tomato lines much more rapidly. Due to changing climates and the need for commercial production of vegetables in low quality fields there is an urgent need for stress tolerant commercial lines of vegetables such as tomato. In previous observations we identified a scion root stock combination ('BHN 602' scion grafted onto 'Jjak Kkung' rootstock hereafter identified as 602/Jjak) that had a qualitative drought-tolerance phenotype when compared to the non-grafted line. Based on this initial observation, we studied photosynthesis and vegetative above-ground growth during mild-drought for the 602/Jjak compared with another scion-rootstock combination ('BHN 602' scion grafted onto 'Cheong Gang' rootstock hereafter identified as 602/Cheong) and a non-grafted control. Overall above ground vegetative growth was significantly lower for 602/Jjak in comparison to the other plant lines. Moreover, water potential reduction in response to mild drought was significantly less for 602/Jjak, yet stomatal conductance of all plant-lines were equally inhibited by mild-drought. Light saturated photosynthesis of 602/Jjak was less affected by low water potential than the other two lines as was the % reduction in mesophyll conductance. Therefore, the Jjak Kkung rootstock caused aboveground growth reduction, water conservation and increased photosynthetic tolerance of mild drought. These data show that different rootstocks can change the photosynthetic responses to drought of a high yielding, commercial tomato line. Also, this rapid discovery of one scion-rootstock combination that provided mild-drought tolerance suggests that screening more scion-rootstock combination for stress tolerance may rapidly yield commercially viable, stress tolerant lines of tomato. PMID:25531435

Nilsen, Erik T; Freeman, Joshua; Grene, Ruth; Tokuhisa, James

2014-01-01

145

Hepatotoxicity of mild analgesics  

PubMed Central

1 Hepatotoxicity is rare when mild analgesics are used in normal therapeutic doses. 2 The potential of aspirin and salicylates to cause hepatotoxicity has been only recently recognized. 3 Salicylate hepatitis is often asymptomatic, and may only be revealed by finding elevated levels of aminotransferases. 4 Most cases have occurred in children or young adults with connective tissue diseases, who take high doses of salicylates for long periods. 5 Hepatic injury is not recognized as a complication of acute aspirin poisoning. 6 Following overdosage of paracetamol, a toxic intermediate metabolite causes acute hepatic necrosis which may be fatal. 7 Cysteamine, methionine and N-acetylcysteine confer protection against this severe liver damage, but the time between overdosage and treatment is critical. 8 The chronic therapeutic use of paracetamol should be considered a potential but very rare cause of active chronic hepatitis. 9 There is no clear evidence of phenacetin hepatotoxicity in man. 10 Phenylbutazone may cause liver injury and other analgesics can cause hypersensitivity reactions in which the liver is involved. ImagesFigure 2 PMID:7002191

Prescott, L. F.

1980-01-01

146

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

PubMed

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. PMID:22674537

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

2012-07-01

147

A mild, convenient, and inexpensive procedure for conversion of vinyl halides to alpha-haloketones.  

PubMed

Treatment of a vinyl chloride with commercially available aqueous sodium hypochlorite solution in a 2:5 mixture of acetic acid/acetone at 0 degrees C for about 1 h cleanly leads to the corresponding alpha-chloroketone. Similarly, if a vinyl bromide is exposed to sodium hypobromite (freshly prepared from bromine and sodium hydroxide) at 0 degrees C in 2:5 acetic acid/acetone as solvent, an alpha-bromoketone is produced. This methodology has been applied to a number of vinyl chlorides and vinyl bromides, and the transformations generally proceed in high yields. The mild reaction conditions are compatible with a variety of functional groups including amides, esters, and imines. PMID:12688812

VanBrunt, Michael P; Ambenge, Reuben O; Weinreb, Steven M

2003-04-18

148

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

PubMed Central

Summary ?-Cyclodextrin (?-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 ?-CD units in a single step and in aqueous/organic media, under mild conditions and with good yields. A three-carbon spacer between the ?-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 ?-CD cavities were capable of guest encapsulation, as shown by titration experiments: the binding constant with 1-adamantylamine was similar to that of natural ?-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 ?-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

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

2014-01-01

149

A simple hydrophilic palladium(II) complex as a highly efficient catalyst for room temperature aerobic Suzuki coupling reactions in aqueous media.  

PubMed

A study on room temperature Suzuki cross-coupling in an aqueous medium was carried out using a simple hydrophilic palladium (II) complex, trans-PdCl2(NH2CH2COOH)2 as catalyst in the presence of K2CO3 in air. This approach with a comparatively inexpensive and hydrophilic catalyst, mild reaction condition and aqueous media exhibits excellent catalytic activity towards the Suzuki coupling of aryl bromides and arylboronic acids, and good yields were obtained in the Suzuki coupling of activated aryl chlorides. PMID:24853715

Guo, Mengping; Liu, Shiwen; Zhou, Xiuling; Lv, Meiyun; Chen, Sanbao; Xiao, Daoan

2014-01-01

150

Electrochemical behaviour of 1024 mild steel in slightly alkaline bicarbonate solutions  

Microsoft Academic Search

The electrochemical behaviour of 1024 mild steel electrodes is investigated in the presence of 0.05–0.5 M sodium bicarbonate in aqueous solution at pH 8.9 and 25°C. Voltammograms are obtained with a rotating gold ring-mild steel electrode and the effect of the NaHCO3 concentration, the potential limits and the rotation speed of the disc electrode is considered. The voltammograms display an

S. SIMARD; M. DROGOWSKA; H. ME´NARD; L. BROSSARD

1997-01-01

151

Modelling paradigms for MILD combustion  

E-print Network

, CB2 1PZ, UK. E-mail: ns341@cam.ac.uk. Phone: +44(0)1223 332586. Fax: +44(0)1223 339906. Running Title: Modelling of MILD combustion Submitted to International Journal of Advances in Engineering Sciences and Applied Mathematics (Special Issue... Modelling paradigms for MILD combustion Y. Minamoto and N. Swaminathan? Department of Engineering, Cambridge University, Cambridge, CB2 1PZ, UK. ?Corresponding author: Department of Engineering, Cambridge University, Trumpington Street, Cambridge...

Minamoto, Y.; Swaminathan, N.

2014-04-26

152

Synthesis of aluminum oxides from the products of the rapid thermal decomposition of hydrargillite in a centrifugal flash reactor: III. Properties of aluminum hydroxides and oxides obtained via the mild rehydration of the products of the centrifugal thermal activation of hydrargillite  

Microsoft Academic Search

The interaction between the amorphous product of the centrifugal thermal activation of hydrargillite (CTA HG) and aqueous\\u000a electrolytes (pH 5–11) under mild conditions (15–35C, atmospheric pressure) has been investigated by a variety of physicochemical\\u000a methods. This interaction causes material morphologic and phase changes in CTA HG, and the product composition is governed\\u000a by the pH of the electrolyte and by

I. V. Kharina; L. A. Isupova; G. S. Litvak; E. M. Moroz; G. N. Kryukova; N. A. Rudina; Yu. Yu. Tanashev; V. N. Parmon

2007-01-01

153

Conditions?  

Microsoft Academic Search

Research interests in feral hogs typically involve their negative impacts on ecosystems or their potential as a disease reservoir, especially with disease transmission to domestic swine. Authors within scientific literature state that feral hogs were captured as part of their research, but usually fail to mention specific conditions in which hogs were captured. Novice researchers of feral hogs must rely

A. Christy Wyckoff; Scott E. Henke; Kurt C. VerCauteren

154

A review of catalytic issues and process conditions for renewable hydrogen and alkanes by aqueous-phase reforming of oxygenated hydrocarbons over supported metal catalysts  

Microsoft Academic Search

We have recently developed a single-step, low-temperature process for the catalytic production of fuels, such as hydrogen and\\/or alkanes, from renewable biomass-derived oxygenated hydrocarbons. This paper reviews our work in the development of this aqueous-phase reforming (APR) process to produce hydrogen or alkanes in high yields. First, the thermodynamic and kinetic considerations that form the basis of the process are

R. R. Davda; J. W. Shabaker; G. W. Huber; R. D. Cortright; J. A. Dumesic

2005-01-01

155

Eco friendly inhibitor for corrosion inhibition of mild steel in phosphoric acid medium  

Microsoft Academic Search

The inhibition effect of Zenthoxylum alatum plant extract on the corrosion of mild steel in 20, 50 and 88% aqueous orthophosphoric acid has been investigated by weight loss and electrochemical impedance spectroscopy (EIS). Plant extract is able to reduce the corrosion of steel more effectively in 88% phosphoric acid than in 20% phosphoric acid. The effect of temperature on the

G Gunasekaran; L. R Chauhan

2004-01-01

156

Educating Students with Mild Disabilities.  

ERIC Educational Resources Information Center

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"…

Meyen, Edward L., Ed.; And Others

157

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

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.

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

2006-01-01

158

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)

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.

Smith, Micholas Dean

159

Development of mild gasification process  

SciTech Connect

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.

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

1987-11-01

160

Development of mild gasification process  

SciTech Connect

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.

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

1989-01-01

161

Development of mild gasification process  

SciTech Connect

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.

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

1988-02-01

162

Development of mild gasification process  

SciTech Connect

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.

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

1988-07-01

163

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

164

Cholinergic Enhancement of Frontal Lobe Activity in Mild Cognitive Impairment  

ERIC Educational Resources Information Center

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…

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

2004-01-01

165

Music Enhances Autobiographical Memory in Mild Alzheimer's Disease  

ERIC Educational Resources Information Center

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…

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

2012-01-01

166

Music Enhances Autobiographical Memory in Mild Alzheimer's Disease  

Microsoft Academic Search

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 Seasons, and (c) after being exposed

Mohamad El Haj; Virginie Postal; Philippe Allain

2012-01-01

167

Is Vanadate Reduced by Thiols under Biological Conditions?: Changing The Redox Potential of V(V)/V(IV) by Complexation in Aqueous solution  

PubMed Central

Although dogma states that vanadate is readily reduced by glutathione, cysteine and other thiols, there are several examples documenting that vanadium(V)-sulfur complexes can form and be observed. This conundrum has impacted life scientists for more than two decades. Investigation of this problem requires an understanding of both the complexes that form from vanadium(IV) and (V) and a representative thiol in aqueous solution. The reactions of vanadate and hydrated vanadyl cation with 2-mercaptoethanol have been investigated using multinuclear NMR, EPR and UV-vis spectroscopy. Vanadate forms a stable complex of 2:2 stoichiometry with 2-mercaptoethanol at neutral and alkaline pH. In contrast, vanadate can oxidize 2-mercaptoethanol; this process is favored at low pH and high solute concentrations. The complex that forms between aqueous vanadium(IV) and 2-mercaptoethanol has a 1:2 stoichiometry and can be observed at high pH and high 2-mercaptoethanol concentration. The solution structures have been deduced and speciation diagrams prepared. This work demonstrates that both vanadium(IV) and (V)-thiol complexes form and that redox chemistry also takes place. Whether reduction of vanadate takes place is governed by a combination of parameters: pH, solute- and vanadate-concentrations and the presence of other complexing ligands. Based on these results it is now possible to understand the distribution of vanadium in oxidation states (IV) and (V) in the presence of glutathione, cysteine and other thiols and begin to evaluate the forms of the vanadium compounds that exert a particular biological effect including the insulin-enhancing agents, anti-amoebic agents and interactions with vanadium binding proteins. PMID:20359175

Crans, Debbie C.; Zhang, Boyan; Gaidamauskas, Ernestas; Keramidas, Anastasios D.; Willsky, Gail R.; Roberts, Chris R.

2010-01-01

168

Procedures for Increasing Sustained Attention in Adults with Mild Intellectual Disabilities  

ERIC Educational Resources Information Center

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…

Doughty, Adam H.; Williams, Dean C.

2013-01-01

169

Standard partial molar volumes of some aqueous alkanolamines and alkoxyamines at temperatures up to 325 degrees C: functional group additivity in polar organic solutes under hydrothermal conditions.  

PubMed

Apparent molar volumes of dilute aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), N,N-dimethylethanolamine (DMEA), ethylethanolamine (EAE), 2-diethylethanolamine (2-DEEA), and 3-methoxypropylamine (3-MPA) and their salts were measured at temperatures from 150 to 325 degrees C and pressures as high as 15 MPa. The results were corrected for the ionization and used to obtain the standard partial molar volumes, Vo2. A three-parameter equation of state was used to describe the temperature and pressure dependence of the standard partial molar volumes. The fitting parameters were successfully divided into functional group contributions at all temperatures to obtain the standard partial molar volume contributions. Including literature results for alcohols, carboxylic acids, and hydroxycarboxylic acids yielded the standard partial molar volume contributions of the functional groups >CH-, >CH2, -CH3, -OH, -COOH, -O-, -->N, >NH, -NH2, -COO-Na+, -NH3+Cl-, >NH2+Cl-, and -->NH+Cl- over the range (150 degrees C aqueous organic solutes composed of these groups at temperatures up to approximately 310 degrees C and pressures of 10-20 MPa to within a precision of +/-5 cm3 x mol(-1). The model could not be extended to higher temperatures because of uncertainties caused by thermal decomposition. At temperatures above approximately 250 degrees C, the order of the group contributions to Vo2 changes from that observed at 25 degrees C, to become increasingly consistent with the polarity of each functional group. The effect of the dipole moment of each molecule on the contribution to Vo2 from long-range solvent polarization was calculated from the multipole expansion of the Born equation using dipole moments estimated from restricted Hartree-Fock calculations with Gaussian 03 (Gaussian, Inc., Wallingford, CT) and the Onsager reaction-field approximation for solvent effects. Below 325 degrees C, the dipole contribution was found to be less than 2 cm3 x mol(-1) for all the solute molecules studied. At higher temperatures and pressures near steam saturation, the effect is much larger and may explain anomalies in functional group additivity observed in small, very polar solutes. PMID:18412415

Bulemela, E; Tremaine, Peter R

2008-05-01

170

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

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. PMID:24411094

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

2014-01-31

171

Mars aqueous chemistry experiment  

NASA Technical Reports Server (NTRS)

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.

Clark, Benton C.; Mason, Larry W.

1993-01-01

172

Ionic liquid-aqueous solution ultrasonic-assisted extraction of three kinds of alkaloids from Phellodendron amurense Rupr and optimize conditions use response surface.  

PubMed

In this paper, we chose diffident kinds of ionic liquids to optimal selection an optimal one to extract alkaloids from Phellodendron amurense Rupr. Four ionic liquids with diffident carbon chains or anions have been investigated and 1-butyl-3-methylimidazolium bromide with best productivity. Then, selections have been optimized in different conditions, including concentration of ionic liquid, time for ultrasonic treatment, ultrasonic power and solid-liquid ratio. Moreover, three conditions have been comprehensively assessment by response surface methodology, the optimal conditions were determined as follows ultrasonic power 100W, extraction time 75min and ratio of solvent to raw material 1:14. Under these conditions, the yield% (MIX) was 106.7% (extracted by heat reflux being defined 100%). Comparing with other methods, the advantages are saving conserving, time saving, high yield% and especially pollution-free. PMID:25443277

Wang, Wenchao; Li, Qingyong; Liu, Yuhui; Chen, Binbin

2015-05-01

173

Benign convulsion with mild gastroenteritis  

PubMed Central

Benign convulsion with mild gastroenteritis (CwG) is a type of afebrile seizure that occurs in children. CwG is defined as a convulsion in a previously healthy child with no known central nervous system infection or encephalopathy, accompanying mild diarrhea without fever, electrolyte imbalance, or moderate to severe dehydration. Convulsions in CwG are characterized by multiple brief episodes of generalized or focal seizures. Although the etiology and pathophysiology have yet to be fully explained, many pathogenic mechanisms have been proposed including the possibility of direct invasion of the central nervous system by a gastrointestinal virus such as rotavirus or the possibility of indirect influence by the production and effects of certain mediators. The electroencephalogram findings are benign and long-term antiepileptic treatment is typically not required. Long-term prognosis has been favorable with normal psychomotor development. This review provides a general overview of CwG with the goal of allowing physicians practicing in the field of pediatrics to better recognize this unique entity and, ultimately, to minimize unnecessary evaluation and treatment. PMID:25114690

Kang, Ben

2014-01-01

174

Bioenhanced dissolution of dense non-aqueous phase of trichloroethylene as affected by iron reducing conditions: Model systems and environmental samples.  

PubMed

The anaerobic biotransformation of trichloroethylene (TCE) can be affected by competing electron acceptors such as Fe (III). This study assessed the role of Fe (III) reduction on the bioenhanced dissolution of TCE dense non-aqueous phase liquid (DNAPL). Columns were set up as 1-D diffusion cells consisting of a lower DNAPL layer, a layer with an aquifer substratum and an upper water layer that is regularly refreshed. The substrata used were either inert sand or sand coated with 2-line ferrihydrite (HFO) or two environmental Fe (III) containing samples. The columns were inoculated with KB-1 and were repeatedly fed with formate. In none of the diffusion cells, vinyl chloride or ethene was detected while dissolved and extractable Fe (II) increased strongly during 60d of incubation. The cis-DCE concentration peaked at 4.0cm from the DNAPL (inert sand) while it was at 3.4cm (sand+HFO), 1.7cm and 2.5cm (environmental samples). The TCE concentration gradients near the DNAPL indicate that the DNAPL dissolution rate was larger than that in an abiotic cell by factors 1.3 (inert sand), 1.0 (sand+HFO) and 2.2 (both environmental samples). This results show that high bioavailable Fe (III) in HFO reduces the TCE degradation by competitive Fe (III) reduction, yielding lower bioenhanced dissolution. However, Fe (III) reduction in environmental samples was not reducing TCE degradation and the dissolution factor was even larger than that of inert sand. It is speculated that physical factors, e.g. micro-niches in the environmental samples protect microorganisms from toxic concentrations of TCE. PMID:25460750

Paul, Laiby; Smolders, Erik

2015-01-01

175

Aqueous foam toxicology evaluation and hazard review  

SciTech Connect

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.

Archuleta, M.M.

1995-10-01

176

ENCOAL Mild Coal Gasification project  

SciTech Connect

Commissioning of the plant dominated the activities of the ENCOAL field group during this reporting period. The operator training classes were completed, initial plant start-up commenced. On June 17, 1992 all systems were fully integrated and the ENCOAL Mild Gasification Plant became fully operational. The plant operated continuously for 24 hours, and both PDF and CDL were produced. Construction of the project was 100% complete by the end of May. As a result of the construction progress, demobilization of KCI and their subcontractors was concluded. An electrical and instrumentation contract was also awarded during the quarter. This contract, combined with the mechanical maintenance contract awarded earlier, provided excellent assistance for plant commissioning and final construction activities.

Frederick, J.P.

1992-01-01

177

Aetiology of mild mental retardation.  

PubMed Central

A clinical and family study was carried out in 169 children attending schools for the mildly mentally retarded in Southampton to assess the prevalence of recognised medical risk factors; 71 children (42%) had such risk factors. These were prenatal in 22, perinatal in 41, and postnatal in eight. Risk factors of possible, but less certain, significance were found in a further 63 children (37%). In 86 families (51%) there was a history of serious educational problems in both parents. The prevalence of both types of risk factor was higher in the children whose parents had no educational problems. There were, however, 25 children (15%) whose parents had no history of educational problems and in whom medical risk factors were either absent or minimal. PMID:3178264

Lamont, M A; Dennis, N R

1988-01-01

178

Slowing down after a mild traumatic brain injury: a strategy to improve cognitive task performance?  

PubMed

Long-term persistent attention and memory difficulties following a mild traumatic brain injury (TBI) often go undetected on standard neuropsychological tests, despite complaints by mild TBI individuals. We conducted a visual Repetition Detection working memory task to digits, in which we manipulated task difficulty by increasing cognitive load, to identify subtle deficits long after a mild TBI. Twenty-six undergraduate students with a self-report of one mild TBI, which occurred at least 6 months prior, and 31 non-head-injured controls took part in the study. Participants were not informed until study completion that the study's purpose was to examine cognitive changes following a mild TBI, to reduce the influence of "diagnosis threat" on performance. Neuropsychological tasks did not differentiate the groups, though mild TBI participants reported higher state anxiety levels. On our working memory task, the mild TBI group took significantly longer to accurately detect repeated targets on our task, suggesting that slowed information processing is a long-term consequence of mild TBI. Accuracy was comparable in the low-load condition and, unexpectedly, mild TBI performance surpassed that of controls in the high-load condition. Temporal analysis of target identification suggested a strategy difference between groups: mild TBI participants made a significantly greater number of accurate responses following the target's offset, and significantly fewer erroneous distracter responses prior to target onset, compared with controls. Results suggest that long after a mild TBI, high-functioning young adults invoke a strategy of delaying their identification of targets in order to maintain, and facilitate, accuracy on cognitively demanding tasks. PMID:22068441

Ozen, Lana J; Fernandes, Myra A

2012-01-01

179

Coordination Modes of Multidentate Ligands in fac-[Re(CO)3(polyaminocarboxylate)] Analogues of 99mTc Radiopharmaceuticals. Dependence on Aqueous Solution Reaction Conditions  

PubMed Central

We study Re analogues of 99mTc renal agents to interpret previous results at the 99mTc tracer level. The relative propensities of amine donors vs. carboxylate oxygen donors of four L = polyaminocarboxylate ligands to coordinate in fac-[ReI(CO)3L]n complexes were assessed by examining the reaction of fac-[ReI(CO)3(H2O)3]+ under conditions differing in acidity and temperature. All four L [N,N-bis-(2-aminoethyl)glycine (DTGH), N,N-ethylenediaminediacetic acid, diethylenetriamine-N-malonic acid, and diethylenetriamine-N-acetic acid] can coordinate as tridentate ligands while creating a dangling chain terminated in a carboxyl group. Dangling carboxyl groups facilitate renal clearance in fac-[99mTcI(CO)3L]n agents. Under neutral conditions, the four ligands each gave two fac-[ReI(CO)3L]n products with HPLC traces correlating well with known traces of the fac-[99mTcI(CO)3L]n mixtures. Such mixtures are common in renal agents because the needed dangling carboxyl group can compete for a coordination site. However, the HPLC separations needed to assess the biodistribution of a single tracer are impractical in a clinical setting. One goal in investigating this Re chemistry is to identify conditions for avoiding this problem of mixtures in preparations of fac-[99mTcI(CO)3L]n renal tracers. After separation and isolation of the fac-[ReI(CO)3L]n products, NMR analysis of all products and single crystal X-ray crystallographic analysis of both DTGH products as well as one product each from the other L allowed us to establish coordination mode unambiguously. The product favored in acidic conditions has a dangling amine chain and more bound oxygen. The product favored in basic conditions has a dangling carboxyl chain and more bound nitrogen. At the elevated temperatures used for simulating tracer preparation, equilibration was facile (ca. one hour or less), allowing selective formation of one product by utilizing acidic or basic conditions. The results of this fundamental study offer protocols and guidance useful for the design and preparation of fac-[99mTcI(CO)3L]n agents consisting of a single tracer. PMID:20201565

Lipowska, Malgorzata; He, Haiyang; Xu, Xiaolong; Taylor, Andrew T.; Marzilli, Patricia A.; Marzilli, Luigi G.

2010-01-01

180

Efficient synthesis of 2,3-disubstituted-2,3-dihydroquinazolin-4(1H)-ones catalyzed by dodecylbenzenesulfonic acid in aqueous media under ultrasound irradiation.  

PubMed

Synthesis of 2,3-disubstituted-2,3-dihydroquinazolin-4(1H)-one derivatives catalyzed by dodecylbenzenesulfonic acid was carried out in 80-92% yields at 40-42°C within 1-2h in aqueous media via one-pot three-component condensation of isatoic anhydride, aromatic aldehyde and amine under ultrasound irradiation. Convenient work-up procedures, mild reaction conditions, avoiding the use of organic solvents, and friendly to environment are the salient features of this protocol. PMID:25224856

Chen, Bao-Hua; Li, Ji-Tai; Chen, Guo-Feng

2015-03-01

181

Nanoheterogeneous catalytic hydrogenation of N-, O- or S-heteroaromatic compounds by re-usable aqueous colloidal suspensions of rhodium(0)  

Microsoft Academic Search

The hydrogenation of various nitrogen-, oxygen- or sulfur-heterocyclic aromatic compounds by various surfactant-stabilized aqueous rhodium(0) colloidal suspensions was investigated. The nanocatalysts in the size range of 2.1–2.4 nm have been synthesized by reducing RhCl3·3H2O with sodium borohydride and were stabilized by highly water soluble N,N-dimethyl-N-cetyl-N-(2-hydroxyethyl)ammonium bromide or chloride salts. The catalytic reactions were performed under mild reaction conditions, namely room

Vincent Mévellec; Alain Roucoux

2004-01-01

182

Prospective Memory Impairment in Mild Cognitive Impairment: An Analytical Review  

Microsoft Academic Search

Mild cognitive impairment (MCI) is a heterogeneous condition characterized by the presence in an otherwise healthy elderly\\u000a individual of cognitive deficits involving specific domains in the absence of significant functional impairments. Reports\\u000a indicate that prospective memory (PM), that is, the ability to remember to execute delayed intentions, is impaired in individuals\\u000a with MCI. The present review discusses the current debate

Alberto Costa; Carlo Caltagirone; Giovanni Augusto Carlesimo

183

Non syndromic gingival fibromatosis in a mild mental retardation child  

PubMed Central

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

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

2012-01-01

184

Separation of products from mild coal gasification processes  

SciTech Connect

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.

Wallman, P.H.

1991-09-11

185

Submerged arc fillet welds between mild steel and stainless steel  

SciTech Connect

Submerged arc fillet welds between mild steel and Type 304 stainless steel, made with ER309L wire, may contain no ferrite and be at risk of hot cracking, or they may be sufficiently diluted that they transform to martensite with both hot cracking risk and low ductility. This situation is most prevalent when direct current electrode positive (DCEP) polarity is used and when the flange is the mild steel part of the T-joint. A flux that adds chromium to the weld can somewhat alleviate this tendency. Direct current electrode negative (DCEN) polarity greatly reduces this tendency by limiting dilution. Fillet weld compositions and dilutions are obtained for a number of welding conditions and fluxes.

Kotecki, D.J.; Rajan, V.B. [Lincoln Electric Co., Cleveland, OH (United States)

1997-02-01

186

Effect of Machining Parameters on Oxidation Behavior of Mild Steel  

NASA Astrophysics Data System (ADS)

This study aims to find out a correlation between machining parameters, resultant microstructure, and isothermal oxidation behavior of lathe-machined mild steel in the temperature range of 660-710 °C. The tool rake angles "?" used were +20°, 0°, and -20°, and cutting speeds used were 41, 232, and 541 mm/s. Under isothermal conditions, non-machined and machined mild steel samples follow parabolic oxidation kinetics with activation energy of 181 and ~400 kJ/mol, respectively. Exaggerated grain growth of the machined surface was observed, whereas, the center part of the machined sample showed minimal grain growth during oxidation at higher temperatures. Grain growth on the surface was attributed to the reduction of strain energy at high temperature oxidation, which was accumulated on the sub-region of the machined surface during machining. It was also observed that characteristic surface oxide controlled the oxidation behavior of the machined samples. This study clearly demonstrates the effect of equivalent strain, roughness, and grain size due to machining, and subsequent grain growth on the oxidation behavior of the mild steel.

Majumdar, P.; Shekhar, S.; Mondal, K.

2015-01-01

187

Effect of Machining Parameters on Oxidation Behavior of Mild Steel  

NASA Astrophysics Data System (ADS)

This study aims to find out a correlation between machining parameters, resultant microstructure, and isothermal oxidation behavior of lathe-machined mild steel in the temperature range of 660-710 °C. The tool rake angles "?" used were +20°, 0°, and -20°, and cutting speeds used were 41, 232, and 541 mm/s. Under isothermal conditions, non-machined and machined mild steel samples follow parabolic oxidation kinetics with activation energy of 181 and ~400 kJ/mol, respectively. Exaggerated grain growth of the machined surface was observed, whereas, the center part of the machined sample showed minimal grain growth during oxidation at higher temperatures. Grain growth on the surface was attributed to the reduction of strain energy at high temperature oxidation, which was accumulated on the sub-region of the machined surface during machining. It was also observed that characteristic surface oxide controlled the oxidation behavior of the machined samples. This study clearly demonstrates the effect of equivalent strain, roughness, and grain size due to machining, and subsequent grain growth on the oxidation behavior of the mild steel.

Majumdar, P.; Shekhar, S.; Mondal, K.

2014-11-01

188

Breathing during sleep with mild hypoxia.  

PubMed

To investigate ventilatory response to mild hypoxia during non-rapid-eye-movement sleep, we administered approximately 16% O2 (which corresponds to concentrations found in commercial high altitude air craft) to 12 normal subjects by using a Venturi mask, which did not alter the breathing pattern during this study. Under mild hypoxia, inspiratory minute ventilation during sleep showed an initial rapid increase (P less than 0.001) but then declined significantly (P less than 0.001) and stabilized. Stable levels differed among individuals and, compared with those measured before hypoxia, were significantly lower in some subjects, higher in one, and essentially unchanged in the others. The initial rapid increase in minute ventilation after mild hypoxia during sleep correlated with the respective values of hypoxic ventilatory response during the awake state (P less than 0.01), but the final lowered levels did not. We conclude that the ventilatory response after mild hypoxia during sleep is biphasic and hypoxic depression exerts considerable influence on ventilation under mild hypoxia during sleep. So we should take hypoxic depression into consideration to evaluate the response to hypoxia during sleep. PMID:2507505

Chin, K; Ohi, M; Hirai, M; Kuriyama, T; Sagawa, Y; Kuno, K

1989-09-01

189

Laboratory studies of the aqueous-phase oxidation of polyols: submicron particles vs. bulk aqueous solution  

NASA Astrophysics Data System (ADS)

Oxidation in the atmospheric aqueous phase (cloud droplets and deliquesced particles) has received recent attention as a potential pathway for the formation of highly oxidized organic aerosol. Most laboratory studies of aqueous-phase oxidation, however, are carried out in bulk solutions rather than aqueous droplets. Here we describe experiments in which aqueous oxidation of polyols (water-soluble species with chemical formula CnH2n+2On) is carried out within submicron particles in an environmental chamber, allowing for significant gas-particle partitioning of reactants, intermediates, and products. Dark Fenton chemistry is used as a source of hydroxyl radicals, and oxidation is monitored using a high-resolution aerosol mass spectrometer (AMS). Aqueous oxidation is rapid, and results in the formation of particulate oxalate; this is accompanied by substantial loss of carbon to the gas phase, indicating the formation of volatile products. Results are compared to those from analogous oxidation reactions carried out in bulk solution. The bulk-phase chemistry is similar to that in the particles, but with substantially less carbon loss. This is likely due to differences in partitioning of early-generation products, which evaporate out of the aqueous phase under chamber conditions (in which liquid water content is low), but remain in solution for further aqueous processing in the bulk phase. This work suggests that the product distributions from oxidation in aqueous aerosol may be substantially different from those in bulk oxidation experiments. This highlights the need for aqueous oxidation studies to be carried out under atmospherically relevant partitioning conditions, with liquid water contents mimicking those of cloud droplets or aqueous aerosol.

Daumit, K. E.; Carrasquillo, A. J.; Hunter, J. F.; Kroll, J. H.

2014-05-01

190

Laboratory studies of the aqueous-phase oxidation of polyols: submicron particles vs. bulk aqueous solution  

NASA Astrophysics Data System (ADS)

Oxidation in the atmospheric aqueous phase (cloud droplets and deliquesced particles) has received recent attention as a potential pathway for the formation of highly oxidized organic aerosol. Most laboratory studies of aqueous-phase oxidation, however, are carried out in bulk solutions rather than aqueous droplets. Here we describe experiments in which aqueous oxidation of polyols (water-soluble species with chemical formula CnH2n+2On) is carried out within submicron particles in an environmental chamber, allowing for significant gas-particle partitioning of reactants, intermediates, and products. Dark Fenton chemistry is used as a source of hydroxyl radicals, and oxidation is monitored using a high-resolution aerosol mass spectrometer (AMS). Aqueous oxidation is rapid, and results in the formation of particulate oxalate; this is accompanied by substantial loss of carbon to the gas phase, indicating the formation of volatile products. Results are compared to those from analogous oxidation reactions carried out in bulk solution. The bulk-phase chemistry is similar to that in the particles, but with substantially less carbon loss. This is likely due to differences in partitioning of early-generation products, which evaporate out of the aqueous phase under chamber conditions (in which liquid water content is low), but remain in solution for further aqueous processing in the bulk phase. This work suggests that the product distributions from oxidation in aqueous aerosol may be substantially different from those in bulk oxidation experiments. This highlights the need for aqueous oxidation studies to be carried out under atmospherically relevant partitioning conditions, with liquid water contents mimicking those of cloud droplets or aqueous aerosol.

Daumit, K. E.; Carrasquillo, A. J.; Hunter, J. F.; Kroll, J. H.

2014-10-01

191

Mild and General Palladium-Catalyzed Synthesis of Methyl Aryl Ethers Enabled by the Use of a Palladacycle Precatalyst  

E-print Network

A general method for the Pd-catalyzed coupling of methanol with (hetero)aryl halides is described. The reactions proceed under mild conditions with a wide range of aryl and heteroaryl halides to give methyl aryl ethers in ...

Cheung, Chi Wai

192

Ions in Aqueous Solution  

NSDL National Science Digital Library

This 11-page PDF document is part of an environmental geochemistry course taught by Dr. David Sherman at the University of Bristol. Topics include the aqueous behavior of ions based on their size and charge, the meaning of activity of ions in aqueous solution, the equilibrium constant, complexation of ions and hydrolysis of cations. Also included are informative illustrations, diagrams and equations.

Sherman, David M.; Bristol, University O.

193

Mild Traumatic Brain Injury: Educational Techniques  

Microsoft Academic Search

The awareness of mild traumatic brain injury as a health concern has increased across a multitude of athletic settings due to a plethora of research and clinical findings that indicate the serious threat concussions pose, particularly to young athletes. The need to provide risk reduction and health promotion education to athletes and parents necessitates an innovative approach. This study explores

Katherine R Racanelli; Folse

2012-01-01

194

Mild Cognitive Impairment: Clinical Characterization and Outcome  

Microsoft Academic Search

Results: The primary distinction between control sub- jects and subjects with MCI was in the area of memory, while other cognitive functions were comparable. How- ever, when the subjects with MCI were compared with the patients with very mild AD, memory performance was similar, but patients with AD were more impaired in other cognitive domains as well. Longitudinal performance dem-

Ronald C. Petersen; Glenn E. Smith; Stephen C. Waring; Robert J. Ivnik; Eric G. Tangalos; Emre Kokmen

1999-01-01

195

Mildly Retarded Adults: Their Attitudes Toward Retardation  

ERIC Educational Resources Information Center

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)

Gan, Jennifer; And Others

1977-01-01

196

Structural correlates of mild cognitive impairment  

Microsoft Academic Search

The structural correlates of mild cognitive impairment (MCI) were examined in 105 elderly subjects whose cognitive function ranged from intact to demented, including 38 subjects with MCI. Hippocampal volumes (left and right HcV), brain volume (BV), and grey matter volume (GMV) and white matter volume (WMV) were segmented from high resolution magnetic resonance data sets and normalised to intracranial volume

Henrike Wolf; Anke Hensel; Frithjof Kruggel; Steffi G. Riedel-Heller; Thomas Arendt; Lars-Olof Wahlund; Hermann-Josef Gertz

2004-01-01

197

Educating Students with Mild Mental Retardation.  

ERIC Educational Resources Information Center

This article examines the history of educating students with mild mental retardation and includes discussion of general demographic trends, contextual factors that influenced this process, assessment and instructional practices, and teacher roles and preparation. It then examines these same features currently and offers recommendations for…

Patton, James R.; Polloway, Edward A.; Smith, Tom E. C.

2000-01-01

198

Selective extraction of metal ions from aqueous phase to ionic liquids: a novel thermodynamic approach to separations.  

PubMed

The selective extraction of metals from aqueous mixtures has generally relied on the use of selective ionophores. We present an alternative strategy that exploits a recently developed approach to extraction into an ionic liquid phase, and show that a high degree of control over selectivity can be obtained by tuning the relative concentrations of extraction agents. A thermodynamic model for the approach is presented, and an experimental separation of strontium and potassium ions is performed. It is shown that tuning the concentrations of the species involved can shift the ratio of potassium to strontium in the ionic liquid phase from 4:1 to 3:4. This extraction is performed under mild conditions with relatively common reagents. The result is a proof-of-concept for a novel separations scheme that could have great importance in a wide range of technological applications. PMID:25155578

Janssen, Camiel H C; Sánchez, Antonio; Kobrak, Mark N

2014-11-10

199

Behavior of cellulose and xylan in aqueous ammonia pretreatment.  

PubMed

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. PMID:25245678

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

2014-12-01

200

Development of an advanced, continuous mild gasification process for the production of co-products  

SciTech Connect

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.

Wolfe, R.A.; Wright, R.E.; Im, C.J.; Henkelman, M.R.; O`Neal, G.W.

1992-11-01

201

Corrosion inhibited aqueous slurries  

SciTech Connect

This invention relates to the use of phospho-compositions, for example phosphates, pyrophosphates, polyphosphates, organophosphates, etc., as corrosion inhibitors in oxygen-containing aqueous systems of particulate matter such as slurries of solids, such as coal, etc.

French, E.; Braga, Th.G.

1985-02-19

202

Mechanism of chitosan adsorption on silica from aqueous solutions.  

PubMed

We present a study of the adsorption of chitosan on silica. The adsorption behavior and the resulting layer properties are investigated by combining optical reflectometry and the quartz crystal microbalance. Exactly the same surfaces are used to measure the amount of adsorbed chitosan with both techniques, allowing the systematic combination of the respective experimental results. This experimental protocol makes it possible to accurately determine the thickness of the layers and their water content for chitosan adsorbed on silica from aqueous solutions of varying composition. In particular, we study the effect of pH in 10 mM NaCl, and we focus on the influence of electrolyte type and concentration for two representative pH conditions. Adsorbed layers are stable, and their properties are directly dependent on the behavior of chitosan in solution. In mildly acidic solutions, chitosan behaves like a weakly charged polyelectrolyte, whereby electrostatic attraction is the main driving force for adsorption. Under these conditions, chitosan forms rigid and thin adsorption monolayers with an average thickness of approximately 0.5 nm and a water content of roughly 60%. In neutral solutions, on the other hand, chitosan forms large aggregates, and thus adsorption layers are significantly thicker (?10 nm) as well as dissipative, resulting in a large maximum of adsorbed mass around the pK of chitosan. These films are also characterized by a substantial amount of water, up to 95% of their total mass. Our results imply the possibility to produce adsorption layers with tailored properties simply by adjusting the solution chemistry during adsorption. PMID:24725003

Tiraferri, Alberto; Maroni, Plinio; Rodríguez, Diana Caro; Borkovec, Michal

2014-05-01

203

Nova outbursts in the case of mild hibernation  

SciTech Connect

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.

Livio, M.; Shankar, A.; Truran, J.W.

1988-02-01

204

A Modified Controlled Cortical Impact Technique to Model Mild Traumatic Brain Injury Mechanics in Mice  

PubMed Central

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

Chen, YungChia; Mao, Haojie; Yang, King H.; Abel, Ted; Meaney, David F.

2014-01-01

205

Reflectance of aqueous solutions  

NASA Technical Reports Server (NTRS)

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.

Querry, M. R.

1972-01-01

206

Disposable baby wipes: efficacy and skin mildness.  

PubMed

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

Odio, M; Streicher-Scott, J; Hansen, R C

2001-04-01

207

Maternal non-phenylketonuric mild hyperphenylalaninemia  

Microsoft Academic Search

Unlike maternal phenylketonuria (PKU) which produces severe birth defects when untreated during pregancy, maternal non-PKU\\u000a mild hyperphenylalaninemia (MHP) has a less severe impact but whether it is benign or may have long-term consequences for\\u000a offspring has been unclear. From an international survey of maternal MHP we obtained information about 86 mothers (blood phenylalanine\\u000a (Phe) 150–720 µmol\\/1), their 219 untreated pregnancies

H. L. Levy; S. E. Waisbren; D. Lobbregt; E. Allred; A. Leviton; R. Koch; W. B. Hanley; B. Rouse; R. Matalon; F. de la Cruz

1996-01-01

208

The evolution of mild parkinsonian signs in aging  

PubMed Central

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

Mahoney, Jeannette R.; Verghese, Joe; Holtzer, Roee

2014-01-01

209

The new DSM-5 diagnosis of mild neurocognitive disorder and its relation to research in mild cognitive impairment.  

PubMed

The Diagnostic Statistical Manual-5 (DSM-5) has included a category named the neurocognitive disorder which was formally known in DSM-IV as 'dementia, delirium, amnestic, and other cognitive disorders'. The DSM-5 distinguishes between 'mild' and 'major' neurocognitive disorders. Major neurocognitive disorder replaces the DSM-IV's term 'dementia or other debilitating conditions'. A pivotal addition is 'mild neurocognitive disorder (mNCD)' defined by a noticeable decrement in cognitive functioning that goes beyond normal changes seen in aging. It is a disorder that may progress to dementia - importantly, it may not. Presently, our understanding of mNCD is derived from research on mild cognitive impairment (MCI). Whereas there is currently no clear treatment for mNCD, many experimental therapies now and into the future will focus upon secondary prevention, namely decreasing the risk of progression to major NCD. In this article, we will focus on mNCD by reviewing the relevant literature on MCI. We will review the research on the incidence and prevalence of MCI, conversion rates from MCI to dementia, risk factors for conversion of MCI to dementia, comorbidity of MCI with other neuropsychiatric disorders (NPS), and the development of treatment strategies for neuropsychiatric disorders in MCI. The presence of NPS is common among individuals with MCI and is an important risk for progression to dementia. However, there has been little research on effective treatments for NPS in MCI. Clinicians and investigators must determine if the treatment of the NPS in mNCD will improve quality of life and help reduce the progression of the cognitive impairment. PMID:24914889

Sachs-Ericsson, Natalie; Blazer, Dan G

2015-01-01

210

Size and shape-controlled synthesis of colloidal gold through autoreduction of the auric cation by poly(ethylene oxide) poly(propylene oxide) block copolymers in aqueous solutions at ambient conditions  

Microsoft Academic Search

Gold nanoparticles with an average diameter in the range 5-20 nm have been synthesized from hydrogen tetrachloroaureate (III) hydrate (HAuCl4·3H2O) in air-saturated aqueous PEO-PPO-PEO block copolymer solutions at ambient temperature in the absence of any other reducing agent (PEO: poly(ethylene oxide), PPO: poly(propylene oxide)). The particle size was controlled by the block copolymer concentration and PEO and PPO block lengths.

Toshio Sakai; Paschalis Alexandridis

2005-01-01

211

People with Mild to Moderate Intellectual Disability Talking about Their Diabetes and How They Manage  

ERIC Educational Resources Information Center

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…

Cardol, M.; Rijken, M.; van Schrojenstein Lantman-de Valk, H.

2012-01-01

212

Ultra-mild wear of a hypereutectic Al–18.5 wt.% Si alloy  

Microsoft Academic Search

Material removal rate from an automotive engine bore surface should not exceed a few nanometers per running hour. This corresponds to the ultra-mild wear (UMW) conditions. Understanding the role of the microstructure on the wear mechanisms in the UMW regime is essential for the development of lightweight automotive engines. In this work, sliding wear tests were performed on a hypereutectic

M. Chen; A. T. Alpas

2008-01-01

213

Simulation of mild wear in boundary lubricated spherical roller thrust bearings  

Microsoft Academic Search

Owing to the curved contact surfaces in a spherical roller thrust bearing, the rollers will undergo sliding. For an unskewed roller there will be two points along each contact where the sliding velocity is zero. At all other points along the contact, sliding is present. Under boundary lubricated conditions the sliding can give rise to mild wear. Experimental results show

Ulf Olofsson; Sören Andersson; Stefan Björklund

2000-01-01

214

Understanding failure of visual paired associate learning in amnestic mild cognitive impairment  

Microsoft Academic Search

Impairment in visual paired associate learning occurs often in with amnestic mild cognitive impairment (aMCI), a condition considered to be an early stage of Alzheimer's disease (AD). To date, studies of aMCI have characterized impaired visual paired associate learning only in terms of summary scores such as total errors or total trials to criterion. The aim of this study was

Jade ODonnell; Robert H. Pietrzak; Kathryn C. Ellis; Peter J. Snyder; Paul Maruff

2011-01-01

215

The Croydon Assessment of Learning Study: Prevalence and Educational Identification of Mild Mental Retardation  

ERIC Educational Resources Information Center

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…

Simonoff, Emily; Pickles, Andrew; Chadwick, Oliver; Gringras, Paul; Wood, Nicky; Higgins, Siobhan; Maney, Julie-Ann; Karia, Nisha; Iqbal, Huma; Moore, Anne

2006-01-01

216

Increasing the Probability of Stimulus Equivalence with Adults with Mild Mental Retardation  

ERIC Educational Resources Information Center

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…

Saunders, Richard R.; McEntee, Julie, E.

2004-01-01

217

Association between Elevated Homocysteine Concentration and Alzheimer's Disease, Vascular Dementia, and Mild Cognitive Impairment  

Microsoft Academic Search

Background: Alzheimer's disease (AD) and vascular dementia (VaD) are the common causes of dementia. Mild cognitive impairment (MCI) refers to the clinical condition between normal aging and dementia. Recent studies have appraised the possibility that homocysteine might play a r ole in the pathogeneses not only of VaD but also of AD. The purpose of this study was to investigate

Sun-Young Cho; Sang-Beom Kim; Mi-Sun Lee; Hee Jin Kim; Jiyoung Yun; Kunha Kim; Kyoung-Gyu Choi; Byung-Ok Choi

2006-01-01

218

Is Mild Dementia Related to Unsafe Street-Crossing Decisions?  

PubMed

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. PMID:25494367

Dommes, Aurélie; Wu, Ya-Huei; Aquino, Jean-Pierre; Pitti-Ferrandi, Hélène; Soleille, Martine; Martineau-Fleury, Sophie; Samson, Michel; Rigaud, Anne-Sophie

2014-12-01

219

Fast and sensitive detection of protein concentration in mild environments.  

PubMed

Determination of protein concentration in mild environments is of great significance in the clinic diagnose and bioassay. Herein, a simple, fast and sensitive method for protein quantitative determination in neutral solution (pH 7.0) is developed. This assay is based on competition adsorption of the sample protein and fluorescently labeled dog serum albumin (FITC-DSA) onto gold nanoparticles (AuNPs). As the competitor FITC-DSA molecules are added into the mixture solution of sample protein conjugated AuNPs, they will compete for active sites of AuNPs, resulting in decrease in fluorescence intensity due to the quenching effect of AuNPs via fluorescence resonance energy transfer (FRET). Thus, quantitative determination of sample protein concentration can be achieved. Under the optimum conditions, the decrease in fluorescence intensity of the solution is related to the concentration of sample protein and a low detection limit of 0.01µg/mL BSA can be achieved in 5min. For the validation of our strategy in practical applications, the total protein content in human serum was determined using the as-proposed method. The result is in well agreement with that of measured by other conventional methods, suggesting a simple, accurate, and mild approach for protein detection in bioassay. PMID:25640132

Wang, Chen; Zhou, Yue; Zhang, Ke-Xin; Nie, Xing-Guo; Xia, Xing-Hua

2015-04-01

220

An update of corrosion inhibitors for mild steel exposed to 32-0-0 UAN solution  

SciTech Connect

This is a continuation of corrosion studies on the effectiveness of commercial and newly-developed corrosion inhibitors for use with mild steel exposed to urea-ammonium nitrate (UAN) solution. This paper provides updated information on five newly-developed corrosion inhibitors. Tests were conducted with mild steel exposed to 32-0-0 UAN solution containing each corrosion inhibitor at ambient temperature and under static conditions. Real-time corrosion of the test specimens was monitored using AC impedance techniques. Corrosion performance of the inhibitors was evaluated based on comparison of the corrosion rate of specimens exposed to 32-0-0 UAN solution with and without a corrosion inhibitor.

Nguyen, D.T.; Nichols, D.E. [Tennessee Valley Authority, Muscle Shoals, AL (United States); Lohry, E.J. [Nutra-Flo Co., Sioux City, IA (United States)

1994-10-01

221

A Clinical Index to Predict Progression from Mild Cognitive Impairment to Dementia Due to Alzheimer's Disease  

PubMed Central

Background Mild cognitive impairment is often a precursor to dementia due to Alzheimer's disease, but many patients with mild cognitive impairment never develop dementia. New diagnostic criteria may lead to more patients receiving a diagnosis of mild cognitive impairment. Objective To develop a prediction index for the 3-year risk of progression from mild cognitive impairment to dementia relying only on information that can be readily obtained in most clinical settings. Design and Participants 382 participants diagnosed with amnestic mild cognitive impairment enrolled in the Alzheimer's Disease Neuroimaging Initiative (ADNI), a multi-site, longitudinal, observational study. Main Predictors Measures Demographics, comorbid conditions, caregiver report of participant symptoms and function, and participant performance on individual items from basic neuropsychological scales. Main Outcome Measure Progression to probable Alzheimer's disease. Key Results Subjects had a mean (SD) age of 75 (7) years and 43% progressed to probable Alzheimer's disease within 3 years. Important independent predictors of progression included being female, resisting help, becoming upset when separated from caregiver, difficulty shopping alone, forgetting appointments, number of words recalled from a 10-word list, orientation and difficulty drawing a clock. The final point score could range from 0 to 16 (mean [SD]: 4.2 [2.9]). The optimism-corrected Harrell's c-statistic was 0.71(95% CI: 0.68–0.75). Fourteen percent of subjects with low risk scores (0–2 points, n?=?124) converted to probable Alzheimer's disease over 3 years, compared to 51% of those with moderate risk scores (3–8 points, n?=?223) and 91% of those with high risk scores (9–16 points, n?=?35). Conclusions An index using factors that can be obtained in most clinical settings can predict progression from amnestic mild cognitive impairment to probable Alzheimer's disease and may help clinicians differentiate between mild cognitive impairment patients at low vs. high risk of progression. PMID:25486250

Lee, Sei J.; Ritchie, Christine S.; Yaffe, Kristine; Stijacic Cenzer, Irena; Barnes, Deborah E.

2014-01-01

222

Corrosion inhibitor for aqueous ammonia absorption system  

DOEpatents

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.

Phillips, Benjamin A. (Benton Harbor, MI); Whitlow, Eugene P. (St. Joseph, MI)

1998-09-22

223

Corrosion inhibitor for aqueous ammonia absorption system  

DOEpatents

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.

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

1998-09-22

224

Rechargeable hybrid aqueous batteries  

NASA Astrophysics Data System (ADS)

A new aqueous rechargeable battery combining an intercalation cathode with a metal (first order electrode) anode has been developed. The concept is demonstrated using LiMn2O4 and zinc metal electrodes in an aqueous electrolyte containing two electrochemically active ions (Li+ and Zn2+). The battery operates at about 2 V and preliminarily tests show excellent cycling performance, with about 90% initial capacity retention over 1000 charge-discharge cycles. Use of cation-doped LiMn2O4 cathode further improves the cyclability of the system, which reaches 95% capacity retention after 4000 cycles. The energy density for a prototype battery, estimated at 50-80 Wh kg-1, is comparable or superior to commercial 2 V rechargeable batteries. The combined performance attributes of this new rechargeable aqueous battery indicate that it constitutes a viable alternative to commercial lead-acid system and for large scale energy storage application.

Yan, Jing; Wang, Jing; Liu, Hao; Bakenov, Zhumabay; Gosselink, Denise; Chen, P.

2012-10-01

225

Rheology of aqueous foams  

NASA Astrophysics Data System (ADS)

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"

Dollet, Benjamin; Raufaste, Christophe

2014-10-01

226

Responsive aqueous foams.  

PubMed

Remarkable properties have emerged recently for aqueous foams, including ultrastability and responsiveness. Responsive aqueous foams refer to foams for which the stability can be switched between stable and unstable states with a change in environment or with external stimuli. Responsive foams have been obtained from various foam stabilizers, such as surfactants, proteins, polymers, and particles, and with various stimuli. Different strategies have been developed to design this type of soft material. We briefly review the two main approaches used to obtain responsive foams. The first approach is based on the responsiveness of the interfacial layer surrounding the gas bubbles, which leads to responsive foams. The second approach is based on modifications that occur in the aqueous phase inside the foam liquid channels to tune the foam stability. We will highlight the most sophisticated approaches, which use light, temperature, and magnetic fields and lead to switchable foam stability. PMID:25384466

Fameau, Anne-Laure; Carl, Adrian; Saint-Jalmes, Arnaud; von Klitzing, Regine

2015-01-12

227

Atomistic insights into aqueous corrosion of copper  

NASA Astrophysics Data System (ADS)

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- 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.

Jeon, Byoungseon; Sankaranarayanan, Subramanian K. R. S.; van Duin, Adri C. T.; Ramanathan, Shriram

2011-06-01

228

Atomistic insights into aqueous corrosion of copper.  

PubMed

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(-) 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. PMID:21702575

Jeon, Byoungseon; Sankaranarayanan, Subramanian K R S; van Duin, Adri C T; Ramanathan, Shriram

2011-06-21

229

Atomistic insights into aqueous corrosion of copper.  

SciTech Connect

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.

Jeon, B.; Sankaranarayanan, S. K. R. S.; van Duin, A. C. T.; Ramanathan, S. (Center for Nanoscale Materials); (Harvard Univ.); (Penn State Univ.)

2011-06-21

230

Microfluidic culture platform for studying neuronal response to mild to very mild axonal stretch injury.  

PubMed

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

Yap, Yiing C; Dickson, Tracey C; King, Anna E; Breadmore, Michael C; Guijt, Rosanne M

2014-07-01

231

Aqueous carbonaceous slurries  

SciTech Connect

Aqueous carbonaceous slurries having reduced viscosity, a stabilized network of coal in water and improved pumpability are obtained by having present a salt of naphthalenesulfonic acid formaldehyde condensate and at least one water soluble polymer selected from the group consisting of gum karaya, mixtures of gum karaya and polyacrylamide and polysaccaride modified with polyacrylate. For example, a mixture of 61.5% by weight of ammonium naphthalenesulfonic acid formaldehyde condensate and 38.5% by weight of gum karaya can be added to an aqueous coal slurry in an amount of 0.13% by weight of the slurry.

Schick, M.J.; Knitter, K.A.

1983-11-15

232

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)

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 ? - ? (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.

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

2015-01-01

233

Bound states in mildly curved layers  

NASA Astrophysics Data System (ADS)

It has been shown recently that a nonrelativistic quantum particle constrained to a hard-wall layer of constant width built over a geodesically complete simply connected noncompact curved surface can have bound states, provided the surface is not a plane. In this paper we study the weak-coupling asymptotics of these bound states, i.e., the situation when the surface is a mildly curved plane. Under suitable assumptions about regularity and decay of surface curvatures we derive the leading order in the ground-state eigenvalue expansion. The argument is based on Birman-Schwinger analysis of Schrödinger operators in a planar hard-wall layer.

Exner, P.; Krejcirík, D.

2001-08-01

234

Effect of aqueous fraction of Rosa damascena on ileum contractile response of guinea pigs  

PubMed Central

Objective: The use of drugs with herbal origin is increasing for treatment of gastrointestinal (GI) disorders. Rosa damascena (R. damascena) is a well-known plant suggested to have beneficial effect on GI system. In this study, the effect of aqueous fraction of R. damascena on the contractions of isolated guinea pig ileum was investigated. Materials and Methods: Aqueous fraction of plant was obtained from ethanolic extract after ethyl acetate and n-butanol fractions were discarded. To evaluate effect of this fraction on ileum contraction, guinea pig ileum was removed and mounted on organ bath and its contraction was recorded. Effect of various concentrations (0.66, 0.83, and 1.3 mg/ml) of aqueous fraction on ileum contraction in comparison with Ach in presence and absence of atropine, a muscarinic antagonist of cholinergic, was evaluated. The response of ileum to 1 µg/ml of acetylcholine was considered as 100% response. Results: Our results showed that aqueous fractions of R. damascena dose-dependently increased basal guinea pigs ileum contractions (p<0.05 to p<0.001). Maximal contraction of fraction (1.3 mg/ml) induced 23.4 % of maximal Ach response. The contraction of ileum to aqueous fraction was significant decreased in presence 0.001 µg/ml of atropine. Conclusion: It is concluded that aqueous fraction of R. damascena has mild excitatory effect on ileum contraction and this fraction may be beneficial as a mild laxative agent. PMID:25050281

Dolati, Karim; Rakhshandeh, Hassan; Shafei, Mohammad Naser

2013-01-01

235

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

NASA Astrophysics Data System (ADS)

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.

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

236

Continuous aqueous tritium monitor  

DOEpatents

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.

McManus, Gary J. (Idaho Falls, ID); Weesner, Forrest J. (Idaho Falls, ID)

1989-05-30

237

ENCOAL mild coal gasification project. Annual report  

SciTech Connect

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.

Not Available

1993-10-01

238

Diagnosis and treatment of dementia: 3. Mild cognitive impairment and cognitive impairment without dementia  

PubMed Central

Background Mild cognitive impairment and cognitive impairment, no dementia, are emerging terms that encompass the clinical state between normal cognition and dementia in elderly people. Controversy surrounds their characterization, definition and application in clinical practice. In this article, we provide physicians with practical guidance on the definition, diagnosis and treatment of mild cognitive impairment and cognitive impairment, no dementia, based on recommendations from the Third Canadian Consensus Conference on the Diagnosis and Treatment of Dementia, held in March 2006. Methods We developed evidence-based guidelines using systematic literature searches, with specific criteria for study selection and quality assessment, and a clear and transparent decision-making process. We selected studies published from January 1996 to December 2005 that had mild cognitive impairment or cognitive impairment, no dementia, as the outcome. Subsequent to the conference, we searched for additional articles published between January 2006 and January 2008. We graded the strength of evidence using the criteria of the Canadian Task Force on Preventive Health Care. Results We identified 2483 articles, of which 314 were considered to be relevant and of good or fair quality. From a synthesis of the evidence in these studies, we made 16 recommendations. In brief, family physicians should be aware that most types of dementia are preceded by a recognizable phase of mild cognitive decline. They should be familiar with the concepts of mild cognitive impairment and of cognitive impairment, no dementia. Patients with these conditions should be closely monitored because of their increased risk for dementia. Leisure activities, cognitive stimulation and physical activity could be promoted as part of a healthy lifestyle in elderly people and those with mild cognitive impairment. Vascular risk factors should be treated optimally. No other specific therapies can yet be recommended. Interpretation Physicians will increasingly see elderly patients with mild memory loss, and learning an approach to diagnosing states such as mild cognitive impairment is now warranted. Close monitoring for progression to dementia, promotion of a healthy lifestyle and treatment of vascular risk factors are recommended for the management of patients with mild cognitive impairment. Articles to date in this series Chertkow H. Diagnosis and treatment of dementia: Introduction. Introducing a series based on the Third Canadian Consensus Conference on the Diagnosis and Treatment of Dementia. CMAJ 2008;178:316-21. Patterson C, Feightner JW, Garcia A, et al. Diagnosis and treatment of dementia: 1. Risk assessment and primary prevention of Alzheimer disease. CMAJ 2008;178:548-56. Feldman HH, Jacova C, Robillard A, et al. Diagnosis and treatment of dementia: 2. Diagnosis. CMAJ 2008;178:825-36. PMID:18458258

Chertkow, Howard; Massoud, Fadi; Nasreddine, Ziad; Belleville, Sylvie; Joanette, Yves; Bocti, Christian; Drolet, Valérie; Kirk, John; Freedman, Morris; Bergman, Howard

2008-01-01

239

Solubilization of native integral membrane proteins in aqueous buffer by non-covalent chelation with monomethoxy polyethylene glycol (mPEG) polymers  

PubMed Central

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

Janaratne, Thamara K.; Okach, Linda; Brock, Ansgar; Lesley, Scott A.

2011-01-01

240

Adsorption of dyestuff from aqueous solutions through oxalic acid-modified swede rape straw: adsorption process and disposal methodology of depleted bioadsorbents.  

PubMed

Swede rape straw (Brassica napus L.) was modified by oxalic acid under mild conditions producing an efficient dye adsorbent (SRSOA). This low-cost and environmental friendly bioadsorbent was characterized by various techniques and then applied to purify dye-contaminated aqueous solutions. Equilibrium study showed that the Langmuir model demonstrated the best fit to the equilibrium data and the methylene blue (MB) adsorption capacity calculated by this model was 432mgg(-1). The adsorption process and mechanism is also discussed. To properly deal with the dye-loaded bioadsorbents, the disposal methodology is discussed and a biochar based on depleted bioadsorbents was for the first time produced and examined. This method both solved the disposal problem of contaminant-loaded bioadsorbents and produced an useful adsorbent thereafter. The study indicates that SRSOA is a promising substitute for ACs in purifying dye-contaminated wastewater and that producing biochars from contaminant-loaded bioadsorbents maybe a feasible disposal method. PMID:23612179

Feng, Yanfang; Dionysiou, Dionysios D; Wu, Yonghong; Zhou, Hui; Xue, Lihong; He, Shiying; Yang, Linzhang

2013-06-01

241

Tau Reduction Diminishes Spatial Learning and Memory Deficits after Mild Repetitive Traumatic Brain Injury in Mice  

PubMed Central

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

Cheng, Jason S.; Craft, Ryan; Yu, Gui-Qiu; Ho, Kaitlyn; Wang, Xin; Mohan, Geetha; Mangnitsky, Sergey; Ponnusamy, Ravikumar; Mucke, Lennart

2014-01-01

242

In Vitro Analyses of Mild Heat Stress in Combination with Antifungal Agents against Aspergillus fumigatus Biofilm  

PubMed Central

Aspergillus fumigatus biofilms still present a challenge for effective treatment in clinical settings. While mild heat stress has been introduced as a treatment for infectious diseases, the effectiveness of mild heat stress on A. fumigatus biofilm formation and antifungal susceptibility is still unknown. In the present study, confocal laser scanning microscopy (CLSM) was used to image and quantify Aspergillus fumigatus biofilm formation under three different regimens of continuous mild heat stress: at 37, 39, and 41°C. Furthermore, fungal growth has been investigated under the above conditions in combination with antifungal drugs (amphotericin B [AMB], micafungin [MCF], and voriconazole [VOC]) at early and late stages. CLSM analysis showed that higher temperatures induce earlier germination and greater hyphal elongation but poorer polar growth and reduced biofilm thickness. In the early stage of biofilm formation, the combination of treatment at 39 or 41°C with MCF or VOC produced no visible difference in biomass formation from similar treatments at 37°C with the same drug. Interestingly, AMB treatment at 37°C inhibited early stage biofilm formation to a much greater extent than at 39 and 41°C. At the late stage of biofilm formation, the mild heat treatments at 39 and 41°C with AMB, MCF, and VOC inhibited biomass formation compared to that at 37°C. The present data show that mild heat stress has a negative regulatory effect on biofilm formation in vitro, and antifungal drug improvement with mild heat treatment at late-stage biofilm formation provides useful indications of possible effective strategies for clinical management of aspergillosis. PMID:24342649

Zeng, Rong; Li, Min; Chen, Qing; Wang, Le; Zhan, Ping; Wang, Chong; Lv, Guixia; Shen, Yongnian

2014-01-01

243

Mild coal pretreatment to improve liquefaction reactivity  

SciTech Connect

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.

Miller, R.L.

1991-01-01

244

Aqueous chemistry of iodine  

SciTech Connect

The chemistry of iodine has been examined in aqueous solutions of pH 6 to 10 containing 2500 ppM boron as H/sub 3/BO/sub 3/ at temperatures up to 150/sup 0/C using absorption spectrophotometry to identify and monitor the iodine species present. Kinetic rate constants for the disproportionation of the HOI intermediate, 3HOI= IO/sub 3//sup -/ + 2I/sup -/ + 3H/sup +/, have been measured as a function of pH even though no direct spectral evidence for HOI itself has been observed. An HOI partition coefficient >10/sup 4/ has been estimated; results of ionic strength tests are consistent with HOI being present as an uncharged triatomic species in solution. Redox and radiation effects on the aqueous iodine chemistry have also been described. 11 refs., 2 figs., 3 tabs.

Toth, L.M.; Pannell, K.D.; Kirkland, O.L.

1984-01-01

245

Tunable Aqueous Virtual Micropore  

SciTech Connect

A charged microparticle can be trapped in an aqueous environment by forming a narrow virtual pore - a cylindrical space region in which the particle motion in the radial direction is limited by forces emerging from dynamical interactions of the particle charge and dipole moment with an external radiofrequency quadrupole electric field. If the particle satisfies the trap stability criteria, its mean motion is reduced exponentially with time due to the viscosity of the aqueous environment; thereafter the long-time motion of particle is subject only to random, Brownian fluctuations, whose magnitude, influenced by the electrophoretic and dielectrophoretic effects and added to the particle size, determines the radius of the virtual pore, which is demonstrated by comparison of computer simulations and experiment. The measured size of the virtual nanopore could be utilized to estimate the charge of a trapped micro-object.

Park, Jae Hyun nmn [ORNL; Guan, Weihau [Yale University; Reed, Mark A [Yale University; Krstic, Predrag S [ORNL

2012-01-01

246

Continuous aqueous tritium monitor  

DOEpatents

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.

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

1987-10-19

247

Mild Hyperthermia Worsens the Neuropathological Damage Associated with Mild Traumatic Brain Injury in Rats  

PubMed Central

Abstract The effects of slight variations in brain temperature on the pathophysiological consequences of acute brain injury have been extensively described in models of moderate and severe traumatic brain injury (TBI). In contrast, limited information is available regarding the potential consequences of temperature elevations on outcome following mild TBI (mTBI) or concussions. One potential confounding variable with mTBI is the presence of elevated body temperature that occurs in the civilian or military populations due to hot environments combined with exercise or other forms of physical exertion. We therefore determined the histopathological effects of pre- and post-traumatic hyperthermia (39°C) on mTBI. Adult male Sprague-Dawley rats were divided into 3 groups: pre/post-traumatic hyperthermia, post-traumatic hyperthermia alone for 2?h, and normothermia (37°C). The pre/post-hyperthermia group was treated with hyperthermia starting 15?min before mild parasagittal fluid-percussion brain injury (1.4–1.6 atm), with the temperature elevation extending for 2?h after trauma. At 72?h after mTBI, the rats were perfusion-fixed for quantitative histopathological evaluation. Contusion areas and volumes were significantly larger in the pre/post-hyperthermia treatment group compared to the post-hyperthermia and normothermic groups. In addition, pre/post-traumatic hyperthermia caused the most severe loss of NeuN-positive cells in the dentate hilus compared to normothermia. These neuropathological results demonstrate that relatively mild elevations in temperature associated with peri-traumatic events may affect the long-term functional consequences of mTBI. Because individuals exhibiting mildly elevated core temperatures may be predisposed to aggravated brain damage after mTBI or concussion, precautions should be introduced to target this important physiological variable. PMID:22026555

Sakurai, Atsushi; Atkins, Coleen M.; Alonso, Ofelia F.; Bramlett, Helen M.

2012-01-01

248

Making sense of nonsense: experiences of mild cognitive impairment.  

PubMed

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. PMID:22554111

Beard, Renée L; Neary, Tara M

2013-01-01

249

Aqueous Humor Dynamics: A Review  

PubMed Central

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

Goel, Manik; Picciani, Renata G; Lee, Richard K; Bhattacharya, Sanjoy K

2010-01-01

250

Aqueous humor dynamics: a review.  

PubMed

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

Goel, Manik; Picciani, Renata G; Lee, Richard K; Bhattacharya, Sanjoy K

2010-01-01

251

Emergence of cognitive deficits after mild traumatic brain injury due to hyperthermia.  

PubMed

Mild elevations in core temperature can occur in individuals involved in strenuous activities that are risky for potentially sustaining a mild traumatic brain injury (mTBI) or concussion. Recently, we have discovered that mild elevations in brain temperature can significantly aggravate the histopathological consequences of mTBI. However, whether this exacerbation of brain pathology translates into behavioral deficits is unknown. Therefore, we investigated the behavioral consequences of elevating brain temperature to mildly hyperthermic levels prior to mTBI. Adult male Sprague Dawley rats underwent mild fluid-percussion brain injury or sham surgery while normothermic (37 °C) or hyperthermic (39 °C) and were allowed to recover for 7 days. Animals were then assessed for cognition using the water maze and cue and contextual fear conditioning. We found that mTBI alone at normothermia had no effect on long-term cognitive measures whereas mTBI animals that were hyperthermic for 15 min prior to and for 4h after brain injury were significantly impaired on long-term retention for both the water maze and fear conditioning. In contrast, hyperthermic mTBI animals cooled within 15 min to normothermia demonstrated no significant long-term cognitive deficits. Mild TBI irrespective of temperature manipulations resulted in significant short-term working memory deficits. Cortical atrophy and contusions were detected in all mTBI treatment groups and contusion volume was significantly less in hyperthermic mTBI animals that were cooled as compared to hyperthermic mTBI animals that remained hyperthermic. These results indicate that brain temperature is an important variable for mTBI outcome and that mildly elevated temperatures at the time of injury result in persistent cognitive deficits. Importantly, cooling to normothermia after mTBI prevents the development of long-term cognitive deficits caused by hyperthermia. Reducing temperature to normothermic levels soon after mTBI represents a rational approach to potentially mitigate the long-term consequences of mTBI. PMID:25447938

Titus, David J; Furones, Concepcion; Atkins, Coleen M; Dietrich, W Dalton

2015-01-01

252

Flow measurements in a model of the mildly curved femoral artery of man  

NASA Technical Reports Server (NTRS)

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.

Back, L. H.; Kwack, E. Y.; Crawford, D. W.

1990-01-01

253

Atlas-Based Hippocampus Segmentation In Alzheimer's Disease and Mild  

E-print Network

Atlas-Based Hippocampus Segmentation In Alzheimer's Disease and Mild Cognitive Impairment Owen T subjects with Alzheimer's Disease (AD) and mild cognitive impairment (MCI). Methods. Struc- tural MR images with MCI were collected at the University of Pitts- burgh Alzheimer's Disease Research Center. Hippocampi

254

Mild Depression: Its Relation to Stress, Coping and Gender.  

ERIC Educational Resources Information Center

This study investigated the relationship of mild depression to global stress, specific stressors, problem-focused coping, emotion-focused coping, and gender. Existing theory supported expectations that non-depressed and mildly depressed persons would use different coping styles, and perceptions of stressful events and the quantity of stressful…

Hartley, Duane L.; Kolenc, Koleen

255

Impaired Verb Fluency: A Sign of Mild Cognitive Impairment  

ERIC Educational Resources Information Center

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…

Ostberg, Per; Fernaeus, Sven-Erik; Hellstrom, Ake; Bogdanovic, Nenad; Wahlund, Lars Olof

2005-01-01

256

Mild Aphasia: Is This the Place for an Argument?  

ERIC Educational Resources Information Center

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…

Armstrong, Elizabeth; Fox, Sarah; Wilkinson, Ray

2013-01-01

257

Teaching Elementary Social Studies to Students with Mild Disabilities.  

ERIC Educational Resources Information Center

Explains what mild disabilities are and discusses the issue of mainstreaming within the realm of elementary school social studies. Provides strategies for social studies teachers to use when addressing the needs of students with learning disabilities, emotional and behavioral disorders, mild mental retardation, and other health impairments. (CMK)

Taylor, Howard E.; Larson, Susan M.

2000-01-01

258

Recurrent posterior circulatory emboli from a mildly stenosed bicuspid aortic valve.  

PubMed

Bicuspid aortic valve (BAV) is a common condition but is only rarely associated with embolic complications. We describe a 42-year-old man with recurrent posterior circulatory ischemic strokes that resulted in ataxia and cognitive impairment. Transesophageal echocardiography demonstrated a BAV with mild stenosis, moderate calcification, and a dilated ascending aorta. The degree of calcification and the valve phenotype might be important factors implicating the BAV as a rare cause of ischemic stroke. PMID:20833085

Purvis, John; Gordon, Patricia; Flynn, Peter; McCarron, Mark

2011-11-01

259

Effect of mild hypothermia on blood brain barrier disruption induced by oleic acid in rats  

Microsoft Academic Search

The blood-brain barrier (BBB) is essential for the normal function of the central nervous system. The pathological conditions\\u000a induced by brain diseases including cerebral ischemia result in the alteration of BBB integrity. This alteration of BBB is\\u000a relieved by mild hypothermia that has been regarded as an effective therapy for brain injury. Experimental fat embolism by\\u000a intra-arterial administration of fatty

Kyung Min Lee; Jae Hee Jang; Jae Sik Park; Dong Sun Kim; Hyung Soo Han

2009-01-01

260

Exposure to mild stress enhances the reinforcing efficacy of intravenous heroin self-administration in rats  

Microsoft Academic Search

The effect of a mild footshock on intravenous heroin self-administration was examined in male rats. Animals in the stress condition were exposed to 10 min of intermittent footshock (0.5 mA; 0.5 s on, with a mean off period of 40 s) before each of four daily self-administration sessions. Animals in the control group were not exposed to footshock. Following acquisition

Yavin Shaham; Jane Stewart

1994-01-01

261

Mild coal pretreatment to improve liquefaction reactivity  

SciTech Connect

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.

Miller, R.L.

1991-01-01

262

Defective Artemis causes mild telomere dysfunction  

PubMed Central

Background Repair of DNA double strand breaks by non-homologous end joining (NHEJ) requires several proteins including Ku, DNA-PKcs, Artemis, XRCC4, Ligase IV and XLF. Two of these proteins, namely Ku and DNA-PKcs, are also involved in maintenance of telomeres, chromosome end-structures. In contrast, cells defective in Ligase IV and XRCC4 do not show changes in telomere length or function suggesting that these proteins are not involved in telomere maintenance. Since a mouse study indicated that defective Artemis may cause telomere dysfunction we investigated the effects of defective Artemis on telomere maintenance in human cells. Results We observed significantly elevated frequencies of telomeric fusions in two primary fibroblast cell lines established from Artemis defective patients relative to the control cell line. The frequencies of telomeric fusions increased after exposure of Artemis defective cells to ionizing radiation. Furthermore, we observed increased incidence of DNA damage at telomeres in Artemis defective cells that underwent more than 32 population doublings using the TIF (Telomere dysfunction Induced Foci) assay. We have also inhibited the expression levels of DNA-PKcs in Artemis defective cell lines by either using synthetic inhibitor (IC86621) or RNAi and observed their greater sensitivity to telomere dysfunction relative to control cells. Conclusion These results suggest that defective Artemis causes a mild telomere dysfunction phenotype in human cell lines. PMID:20678254

2010-01-01

263

Structural correlates of mild cognitive impairment  

E-print Network

The structural correlates of mild cognitive impairment (MCI) were examined in 105 elderly subjects whose cognitive function ranged from intact to demented, including 38 subjects with MCI. Hippocampal volumes (left and right HcV), brain volume (BV), and grey matter volume (GMV) and white matter volume (WMV) were segmented from high resolution magnetic resonance data sets and normalised to intracranial volume (ICV). Hippocampal volume reductions, but not global brain, white or grey matter atrophy, were associated with MCI. White matter lesion severity did not differ over cognitive states. In multiple logistic regression models, normalised HcV and ICV (indicating premorbid brain volume) were significant predictors of MCI versus normality. Normalised BV and ICV significantly predicted dementia versus MCI. Absolute volumetric measures of HcV and BV yielded comparable classification accuracies. Hippocampal atrophy may be the crucial step for the transition from normality to MCI. Widespread brain atrophy may be the step to determine the transition from MCI to dementia. Brain volume reserve effects appear to be involved in both of these steps.

Henrike Wolf A; Anke Hensel A; Frithjof Kruggel B; Steffi G. Riedel-heller A; Thomas Arendt C; Lars-olof Wahlund D; Hermann-josef Gertz A

264

Structure and Dynamics in Aqueous Solutions of Amphiphilic Sodium Maleate-Containing Alternating Copolymers  

Microsoft Academic Search

The structure of aqueous solutions of sodium maleate copolymers with comonomers of variable hydrophobicity are examined using a combination of small-angle neutron scattering, small-angle X-ray scattering, and rheometry. Semidilute solutions of the copolymers made with mildly hydrophobic comonomers exhibit scattering and rheology that are typical of flexible polyelectrolytes, with a correlation length scaling with polymer concentration as c-R with R)

E. Di Cola; N. Plucktaveesak; T. A. Waigh; R. H. Colby; J. S. Tan; W. Pyckhout-Hintzen; R. K. Heenan

2004-01-01

265

A new concept hybrid electrochemical surpercapacitor: Carbon\\/LiMn 2O 4 aqueous system  

Microsoft Academic Search

We present a new concept hybrid electrochemical surpercapacitor technology in which the activated carbon was used as a negative electrode and a lithium-ion intercalated compound LiMn2O4 as a positive electrode in a mild Li2SO4 aqueous electrolyte. The charge\\/discharge process is associated with the transfer of Li-ion between two electrodes. The hybrid cell exhibits a sloping voltage profile from 0.8 to

Yong-gang Wang; Yong-yao Xia

2005-01-01

266

Radio frequency radiation-induced hyperthermia using Si nanoparticle-based sensitizers for mild cancer therapy.  

PubMed

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

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

267

Radio frequency radiation-induced hyperthermia using Si nanoparticle-based sensitizers for mild cancer therapy  

NASA Astrophysics Data System (ADS)

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.

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

268

Reaction kinetics of hydrothermal depolymerization of poly(ethylene naphthalate), poly(ethylene terephthalate), and polycarbonate with aqueous ammonia solution  

Microsoft Academic Search

Poly(ethylene naphthalate) (PEN), poly(ethylene terephthalate) (PET) and poly(carbonate) (PC) were depolymerized in a semi-batch reactor with a 0.6M aqueous ammonia solution under hydrothermal conditions, at 433–553K and 10MPa, compared with aqueous alkaline (NaOH and KOH) solutions and water alone. The polymers studied were almost completely converted into monomers in an aqueous ammonia solution as well as aqueous NaOH and KOH

Risa Arai; Kentaro Zenda; Kohei Hatakeyama; Kazuko Yui; Toshitaka Funazukuri

2010-01-01

269

Inverse Compton Scattering in Mildly Relativistic Plasma  

NASA Technical Reports Server (NTRS)

We investigated the effect of inverse Compton scattering in mildly relativistic static and moving plasmas with low optical depth using Monte Carlo simulations, and calculated the Sunyaev-Zel'dovich effect in the cosmic background radiation. Our semi-analytic method is based on a separation of photon diffusion in frequency and real space. We use Monte Carlo simulation to derive the intensity and frequency of the scattered photons for a monochromatic incoming radiation. The outgoing spectrum is determined by integrating over the spectrum of the incoming radiation using the intensity to determine the correct weight. This method makes it possible to study the emerging radiation as a function of frequency and direction. As a first application we have studied the effects of finite optical depth and gas infall on the Sunyaev-Zel'dovich effect (not possible with the extended Kompaneets equation) and discuss the parameter range in which the Boltzmann equation and its expansions can be used. For high temperature clusters (k(sub B)T(sub e) greater than or approximately equal to 15 keV) relativistic corrections based on a fifth order expansion of the extended Kompaneets equation seriously underestimate the Sunyaev-Zel'dovich effect at high frequencies. The contribution from plasma infall is less important for reasonable velocities. We give a convenient analytical expression for the dependence of the cross-over frequency on temperature, optical depth, and gas infall speed. Optical depth effects are often more important than relativistic corrections, and should be taken into account for high-precision work, but are smaller than the typical kinematic effect from cluster radial velocities.

Molnar, S. M.; Birkinshaw, M.

1998-01-01

270

Environmental Conditions Environmental Conditions  

E-print Network

Environmental Conditions Environmental Conditions Appendix II The unique geology, hydrology and instream habitat. This chapter examines how environmental conditions in the Deschutes watershed affect, the discussion characterizes the environmental conditions within three watershed areas: the Lower Deschutes

271

Improved intratumoral nanoparticle extravasation and penetration by mild hyperthermia.  

PubMed

Accumulation of nanoparticles in solid tumors depends on their extravasation. However, vascular permeability is very heterogeneous within a tumor and among different tumor types, hampering efficient delivery. Local hyperthermia at a tumor can improve nanoparticle delivery by increasing tumor vasculature permeability, perfusion and interstitial fluid flow. The aim of this study is to investigate hyperthermia conditions required to improve tumor vasculature permeability, subsequent liposome extravasation and interstitial penetration in 4 tumor models. Tumors are implanted in dorsal skin flap window chambers and observed for liposome (~85 nm) accumulation by intravital confocal microscopy. Local hyperthermia at 41°C for 30 min initiates liposome extravasation through permeable tumor vasculature in all 4 tumor models. A further increase in nanoparticle extravasation occurs while continuing heating to 1h, which is a clinically relevant duration. After hyperthermia, the tumor vasculature remains permeable for 8h. We visualize gaps in the endothelial lining of up to 10 ?m induced by HT. Liposomes extravasate through these gaps and penetrate into the interstitial space to at least 27.5 ?m in radius from the vessel walls. Whole body optical imaging confirms HT induced extravasation while liposome extravasation was absent at normothermia. In conclusion, a thermal dose of 41°C for 1h is effective to induce long-lasting permeable tumor vasculature for liposome extravasation and interstitial penetration. These findings hold promise for improved intratumoral drug delivery upon application of local mild hyperthermia prior to administration of nanoparticle-based drug delivery systems. PMID:23391444

Li, Li; ten Hagen, Timo L M; Bolkestein, Michiel; Gasselhuber, Astrid; Yatvin, Jeremy; van Rhoon, Gerard C; Eggermont, Alexander M M; Haemmerich, Dieter; Koning, Gerben A

2013-04-28

272

Neurobehavioral aspects of postconcussive symptoms after mild head injury.  

PubMed

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

Bohnen, N; Jolles, J

1992-11-01

273

Organic acids enhance halogen activation on mildly acidic water surfaces  

NASA Astrophysics Data System (ADS)

Iodine species of marine origin are ubiquitous in the marine boundary layer (MBL). They are found over the open ocean (even in the absence of biogenic sources), the Antarctic coast, in rain, aerosols, ice, and snow, and participate in HOx/NOx cycles in the MBL. Surface-active organic acids coating the surface marine microlayer (SML) and marine aerosols could affect their chemical/physical properties. Recent field measurements show that organic acids represent ˜50% of the mass of fog waters collected in the US Gulf Coast. Here we report that I2(g) emissions from the heterogeneous reactions of O3(g) with I- (aq) are dramatically enhanced in the presence of surface-active organic acids under mildly acidic condition that are typical of fine marine aerosols. The amphiphilic weak carboxylic acids appear to promote I2(g) emissions by donating the interfacial protons more efficiently than water itself. We infer that the organic acids coating aerosol particles ejected from ocean's surface films could enhance I2(g) production in the MBL.

Hayase, S.; Enami, S.; Yabushita, A.; Kawasaki, M.; Hoffmann, M. R.; Colussi, A. J.

2011-12-01

274

Plasmon-driven sequential chemical reactions in an aqueous environment  

PubMed Central

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

Zhang, Xin; Wang, Peijie; Zhang, Zhenglong; Fang, Yurui; Sun, Mengtao

2014-01-01

275

Nanofibrous architecture of silk fibroin scaffolds prepared with a mild self-assembly process  

PubMed Central

Besides excellent biocompatibility and biodegradability, a useful tissue engineering scaffold should provide suitable macropores and nanofibrous structure, similar to extracellular matrix (ECM), to induce desired cellular activities and to guide tissue regeneration. In the present study, a mild process to prepare porous and nanofibrous silk based scaffolds from aqueous solution is described. Using collagen to control the self-assembly of silk, nanofibrous silk scaffolds were firstly achieved through lyophilization. Water annealing was used to generate insolubility in the silk based scaffolds, thereby avoiding the use of organic solvents. The nano-fibrils formed in the silk-collagen scaffolds had diameters of 20-100 nanometers, similar with native collagen in ECM. The silk-collagen scaffolds dissolved slowly in PBS solution, with about a 28% mass lost after 4 weeks. Following the dissolution or degradation, the nanofibrous structure inside the macropore walls emerged and interacted with cells directly. During in vitro cell culture, the nanofibrous silk-collagen scaffolds containing 7.4% collagen demonstrated significantly improved cell-compatibility when compared with salt-leached silk scaffolds and silk-collagen scaffolds containing 20% collagen that emerged less nano-fibrils. Therefore, this new process provides useful scaffolds for tissue engineering applications. Furthermore, the process involves all-aqueous, room temperature and pressure processing without the use of toxic chemicals or solvents, offering new green chemistry approaches, as well as options to load bioactive drugs or growth factors into process. PMID:20970185

Lu, Qiang; Wang, Xiuli; Lu, Shenzhou; Li, Mingzhong; Kaplan, David L; Zhu, Hesun

2010-01-01

276

Aqueous shunts for glaucoma  

PubMed Central

Background Aqueous shunts are employed for intraocular pressure (IOP) control in primary and secondary glaucomas that fail medical, laser, and other surgical therapies. Objectives This review compares aqueous shunts for IOP control and safety. Search strategy We searched CENTRAL, MEDLINE, PubMed, EMBASE, NRR in January 2006, LILACS to February 2004 and reference lists of included trials. Selection criteria We included all randomized and quasi-randomized trials in which one arm of the study involved shunts. Data collection and analysis Two authors independently extracted data for included studies and a third adjudicated discrepancies. We contacted investigators for missing information. We used fixed-effect models and summarized continuous outcomes using mean differences. Main results We included fifteen trials with a total of 1153 participants with mixed diagnoses. Five studies reported details sufficient to verify the method of randomization but only two had adequate allocation concealment. Data collection and follow-up times were variable. Meta-analysis of two trials comparing Ahmed implant with trabeculectomy found trabeculectomy resulted in lower mean IOPs 11 to 13 months later (mean difference 3.81 mm Hg, 95% CI 1.94 to 5.69 mm Hg). Meta-analysis of two trials comparing double-plate Molteno implant with the Schocket shunt was not done due to substantial heterogeneity. One study comparing ridged with standard double-plate Molteno implants found no clinically significant differences in outcome. Two trials investigating the effectiveness of adjunctive mitomycin (MMC) with the Molteno and Ahmed implants found no evidence of benefit with MMC. Two trials that investigated surgical technique variations with the Ahmed found no benefit with partial tube ligation or excision of Tenon's capsule. One study concluded there were outcome advantages with a double versus a single-plate Molteno implant and one trial comparing the 350 mm2 and 500 mm2 Baerveldt shunts found no clinically significant advantage of the larger device but neither of these trials included all patients randomized. One study suggested improved clinical outcome when MMC was employed with a newly described shunt including ultrasound supporting the conclusion. One small study did not demonstrate an outcome advantage to systemic steroid use postoperatively with single-plate Molteno shunts. One study comparing endocyclophotocoagulation (ECP) with Ahmed implant in complicated glaucomas found no evidence of better IOP control with Ahmed implant over ECP. Authors' conclusions Relatively few randomized trials have been published on aqueous shunts and methodology and data quality among them is poor. To date there is no evidence of superiority of one shunt over another. PMID:16625616

Minckler, Don; Vedula, Satyanarayana S; Li, Tianjing; Mathew, Milan; Ayyala, Ramesh; Francis, Brian

2014-01-01

277

Poly(ethylene glycol) as reaction medium for mild Mizoroki-Heck reaction in a ball-mill.  

PubMed

Phosphine-free palladium-catalyzed Mizoroki-Heck reaction was performed using ball-milling in polyethylene glycol under mild conditions. Good to excellent yields of coupling products were obtained. This activation technique also allowed the concomitant formation of round shaped Pd-PEG nanoparticles that were characterized by TEM analysis. PMID:23104100

Declerck, Valérie; Colacino, Evelina; Bantreil, Xavier; Martinez, Jean; Lamaty, Frédéric

2012-12-14

278

Effect of Mild Nitric Acid Oxidation on Dispersability, Size, and Structure of Single-Walled Carbon Nanotubes  

E-print Network

Effect of Mild Nitric Acid Oxidation on Dispersability, Size, and Structure of Single-Walled Carbon) with nitric acid increases their dispersability in water, methanol, and N,N-dimethylformamide. Two oxidation conditions carefully. Nitric acid has been the most frequently utilized agent for oxidation of carbon

Resasco, Daniel

279

Training of attentional control in mild cognitive impairment with executive deficits: Results from a double-blind randomised controlled study  

Microsoft Academic Search

This study evaluated the efficacy of a cognitive intervention for attentional control in older adults with mild cognitive impairment (MCI) with an executive deficit. It also sought to verify if the benefits of training generalised to primary and secondary outcome measures. Participants (n?=?24) were randomly assigned to a training programme or active control condition. The experimental group completed a computer-based

Lyssa G. Gagnon; Sylvie Belleville

2012-01-01

280

Factors affecting emulsion stability and quality of oil recovered from enzyme-assisted aqueous extraction of soybeans.  

PubMed

The objectives of the present study were to assess how the stability of the emulsion recovered from aqueous extraction processing of soybeans was affected by characteristics of the starting material and extraction and demulsification conditions. Adding endopeptidase Protex 6L during enzyme-assisted aqueous extraction processing (EAEP) of extruded soybean flakes was vital to obtaining emulsions that were easily demulsified with enzymes. Adding salt (up to 1.5 mM NaCl or MgCl(2)) during extraction and storing extruded flakes before extraction at 4 and 30 degrees C for up to 3 months did not affect the stabilities of emulsions recovered from EAEP of soy flour, flakes and extruded flakes. After demulsification, highest free oil yield was obtained with EAEP of extruded flakes, followed by flour and then flakes. The same protease used for the extraction step was used to demulsify the EAEP cream emulsion from extruded full-fat soy flakes at concentrations ranging from 0.03% to 2.50% w/w, incubation times ranging from 2 to 90 min, and temperatures of 25, 50 or 65 degrees C. Highest free oil recoveries were achieved at high enzyme concentrations, mild temperatures, and short incubation times. Both the nature of enzyme (i.e., protease and phospholipase), added alone or as a cocktail, concentration of enzymes (0.5% vs. 2.5%) and incubation time (1 vs. 3 h), use during the extraction step, and nature of enzyme added for demulsifying affected free oil yield. The free oil recovered from EAEP of extruded flakes contained less phosphorus compared with conventional hexane-extracted oil. The present study identified conditions rendering the emulsion less stable, which is critical to increasing free oil yield recovered during EAEP of soybeans, an environmentally friendly alternative processing method to hexane extraction. PMID:19570674

Jung, S; Maurer, D; Johnson, L A

2009-11-01

281

Chronic mild stress eliminates the neuroprotective effect of Copaxone after CNS injury  

PubMed Central

Copolymer (Cop)-1, also known as glatiramer acetate, is an active compound of Copaxone, a drug widely used by patients with multiple sclerosis (MS). Copaxone functions in MS through two mechanisms of action, namely immunomodulation and neuroprotection. Because the immune system is suppressed or altered in depressed individuals, and since depression is often associated with neurological conditions, we were interested in examining whether the neuroprotective effect of Copaxone persists under conditions of stress-induced depressive behavior. We exposed mice to unpredictable chronic mild stress for 4 weeks and then treated them with three doses of Copaxone at 3-day intervals, with the last dose given immediately before the mice underwent a crush injury to the optic nerve. Whereas nonstressed mice exhibited a strong neuroprotective response after Copaxone treatment, this effect was completely absent in mice that underwent chronic mild stress. Interestingly, when Copaxone was combined with Prozac, the neuroprotective effect of Copaxone was regained, suggesting that chronic mild stress interferes with the neuroprotective effect of Copaxone. These results may shed a light on mechanism of action of Copaxone and lead to new combined therapies for neurodegenerative and neuroinflammatory disorders. PMID:23295266

Smirnov, Igor; Walsh, James T.; Kipnis, Jonathan

2013-01-01

282

Nutritional condition of Northern Yellowstone Elk  

USGS Publications Warehouse

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.

Cook, R.C.; Cook, J.G.; Mech, L.D.

2004-01-01

283

Permeability of aqueous foams  

NASA Astrophysics Data System (ADS)

We perform forced-drainage experiments in aqueous foams and compare the results with data available in the literature. We show that all the data can be accurately compared together if the dimensionless permeability of the foam is plotted as a function of liquid fraction. Using this set of coordinates highlights the fact that a large part of the published experimental results corresponds to relatively wet foams ( \\varepsilon ˜ 0.1). Yet, most of the foam drainage models are based on geometrical considerations only valid for dry foams. We therefore discuss the range of validity of the different models in the literature and their comparison to experimental data. We propose extensions of these models considering the geometry of foam in the relatively wet-foam limit. We eventually show that if the foam geometry is correctly described, forced drainage experiments can be understood using a unique parameter -the Boussinesq number.

Lorenceau, E.; Louvet, N.; Rouyer, F.; Pitois, O.

2009-03-01

284

Late Postpartum HELLP Syndrome 60 Hours after Delivery Associated with Mild Pre-eclampsia  

PubMed Central

The purpose of this report is to present a case of mild Pre-eclampsia which was complicated with postpartum HELLP syndrome. A 25-years-old pregnant woman with mild Pre-eclampsia at 36 weeks of gestation was admitted to our clinic with uterine contractions. A caesarean section was performed, due to her previous caesarean section history. Postpartum period was uneventful until the 2nd day after the caesarean section. Epigastric pain, nausea and vomiting appeared two days after her delivery. In evaluation of the case, laboratory findings which were associated with HELLP syndrome were found to include haemolysis, elevated liver enzymes and low platelet counts. The general condition and laboratory findings of the case returned to normal with supportive and steroid treatment after 3 days. It should be noted that HELLP syndrome can develop in the postpartum period. Therefore, caution should be exercised in patients with pre-eclampsia, for the development of the postpartum HELLP syndrome. PMID:24551706

Cakmak, Bulent; Toprak, Muhammet; Nacar, Mehmet Can; Karatas, Ahmet

2013-01-01

285

Late Postpartum HELLP Syndrome 60 Hours after Delivery Associated with Mild Pre-eclampsia.  

PubMed

The purpose of this report is to present a case of mild Pre-eclampsia which was complicated with postpartum HELLP syndrome. A 25-years-old pregnant woman with mild Pre-eclampsia at 36 weeks of gestation was admitted to our clinic with uterine contractions. A caesarean section was performed, due to her previous caesarean section history. Postpartum period was uneventful until the 2nd day after the caesarean section. Epigastric pain, nausea and vomiting appeared two days after her delivery. In evaluation of the case, laboratory findings which were associated with HELLP syndrome were found to include haemolysis, elevated liver enzymes and low platelet counts. The general condition and laboratory findings of the case returned to normal with supportive and steroid treatment after 3 days. It should be noted that HELLP syndrome can develop in the postpartum period. Therefore, caution should be exercised in patients with pre-eclampsia, for the development of the postpartum HELLP syndrome. PMID:24551706

Cakmak, Bulent; Toprak, Muhammet; Nacar, Mehmet Can; Karatas, Ahmet

2013-12-01

286

Colonoscopy without prior preparation in mild to moderate active ulcerative colitis.  

PubMed

We evaluated the effect of different types of preparations on the diagnostic yield of colonoscopy (total or limited) in mild to moderate active ulcerative colitis. Our ability to determine the extent of disease and see the mucosa beyond the inflamed areas was assessed in patients receiving no preparation (group A, 72 examinations) and those receiving diphosphosoda enemas (group B, 181 examinations). There were three failures in group A and 11 in group B. In the majority of patients (71% of group A, 83% of group B) the scope could be passed under optimal viewing conditions at least one segment beyond the involved area. In group A the cecum was reached in 16% of the procedures and in group B in 18%. We conclude that in mild to moderate active ulcerative colitis, colonoscopy can be performed without preparation, and still achieve the same results as with preparatory enemas. PMID:2007744

Bat, L; Pines, A; Ron, E; Rosenblum, Y; Levo, Y; Shemesh, E

1991-02-01

287

Mild intellectual disability associated with a progeny of father-daughter incest: genetic and environmental considerations.  

PubMed

We report the case of a 34-year-old female resulting from a father-daughter sexual abuse and presenting a phenotype of mild intellectual disability with minor dysmorphic features. Karyotyping showed a normal 46, XX constitution. Array-based comparative genomic hybridization (array-CGH) revealed a heterozygote 320kb 6p22.3 microdeletion in the proband, encompassing only one known gene, and therefore unlikely to be the cause of the phenotype. However, the role of other genetic factors, such as a recessive condition, could not be ruled out as a putative cause for the phenotype. On the other hand, the role played by a heavily detrimental familial situation on the development and outcome, and possibly leading or contributing to a mild intellectual disability, should be taken into account. PMID:20509080

Ansermet, Francois; Lespinasse, James; Gimelli, Stefania; Béna, Frédérique; Paoloni-Giacobino, Ariane

2010-05-01

288

Aqueous solution synthesis of Pt-M (M = Fe, Co, Ni) bimetallic nanoparticles and their catalysis for the hydrolytic dehydrogenation of ammonia borane.  

PubMed

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

Wang, Shuai; Zhang, Duo; Ma, Yanyun; Zhang, Hui; Gao, Jing; Nie, Yuting; Sun, Xuhui

2014-08-13

289

Cartilage tissue engineering application of injectable gelatin hydrogel with in situ visible-light-activated gelation capability in both air and aqueous solution.  

PubMed

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-?3-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

Lin, Hang; Cheng, Anthony Wai-Ming; Alexander, Peter G; Beck, Angela M; Tuan, Rocky S

2014-09-01

290

Thermal conductivity of aqueous foam  

SciTech Connect

Thermal conductivity plays an important part in the response of aqueous foams used as geothermal drilling fluids. The thermal conductivity of these foams was measured at ambient conditions using the thermal conductivity probe technique. Foam densities studied were from 0.03 to 0.2 g/cm/sup 3/, corresponding to liquid volume fractions of the same magnitude. Microscopy of the foams indicated bubble sizes in the range 50 to 300 ..mu..m for nitrogen foams, and 30 to 150 ..mu..m for helium foams. Bubble shapes were observed to be polyhedral at low foam densities and spherical at the higher densities. The measured conductivity values ranged from 0.05 to 0.12 W/m-K for the foams studied. The predicted behavior in foam conductivity caused by a change in the conductivity of the discontinuous gas phase was observed using nitrogen or helium gas in the foams. Analysis of the probe response data required an interpretation using the full intergral solution to the heat conduction equation, since the thermal capacity of the foam was small relative to the thermal mass of the probe. The measurements of the thermal conductivity of the foams were influenced by experimental effects such as the probe input power, foam drainage, and the orientation of the probe and test cell. For nitrogen foams, the thermal conductivity vs liquid volume fraction was observed to fall between predictions based on the parallel ordering and Russell models for thermal conduction in heterogeneous materials.

Drotning, W.D.; Ortega, A.; Havey, P.E.

1982-05-01

291

Pink Eye: Usually Mild and Easy to Treat  

MedlinePLUS

... Submit What's this? Submit Button CDC Features Pink Eye: Usually Mild and Easy to Treat Language: English ... reddish color. What Are the Symptoms of Pink Eye? The signs and symptoms of pink eye may ...

292

Mild Cognitive Impairment and Progession to Dementia: New Findings  

MedlinePLUS

... C.S. Breitner Mild cognitive impairment and progression to dementia: New findings This information is current as of ... assessment_of_cognitive_dis Assessment of cognitive disorders/dementia entia http://www.neurology.org//cgi/collection/all_ ...

293

No Sustained Improvement in Tumor Oxygenation After Localized Mild Hyperthermia  

Microsoft Academic Search

\\u000a This study has attempted to address the controversy concerning sustained increases in tumor oxygenation upon localized mild\\u000a hyperthermia. While some previous studies have reported transient increases, others have reported persistent increases in\\u000a tumor oxygenation, lasting for upto 2 days after application of mild hyperthermia. In order to determine changes in oxygenation\\u000a at clinically relevant tumor temperatures, experimental tumors in rats

Debra K. Kelleher; Peter Vaupel

294

Johnson - Cook Strength Models for Mild and DP 590 Steels  

Microsoft Academic Search

Automotive steels, Mild and Dual Phase590 (DP590) are characterized in tension at room temperature, using the quasi-static and split Hopkinson bar techniques at various strain rates ranging from ~10-3\\/s to ~1800\\/s. Tension stress-strain data for both the steels are analyzed to determine the Johnson-Cook Strength model constants, J-C strength model constants for mild steel are A=217 MPa, B = 234

K. Vedantam; D. Bajaj; N. S. Brar; S. Hill

2006-01-01

295

Slight\\/Mild Sensorineural Hearing Loss in Children  

Microsoft Academic Search

OBJECTIVE.The goal was to determine the prevalence and effects of slight\\/mild bilateral sensorineural hearing loss among children in elementary school. METHODS.A cross-sectional, cluster-sample survey of 6581 children (response: 85%; grade 1: n 3367; grade 5: n 3214) in 89 schools in Melbourne, Australia, was performed. Slight\\/mild bilateral sensorineural hearing loss was defined as a low- frequency pure-tone average across 0.5,

Melissa Wake; Sherryn Tobin; Barbara Cone-Wesson; Hans-Henrik Dahl; Lynn Gillam; Lisa McCormick; Zeffie Poulakis; Field W. Rickards; Kerryn Saunders; Obioha C. Ukoumunne; Joanne Williams

2010-01-01

296

Development of a Simulation Model for Fluidized Bed Mild Gasifier  

Microsoft Academic Search

A mild gasification method has been developed to provide an innovative clean coal technology. The objective of this study is to developed a numerical model to investigate the thermal-flow and gasification process inside a specially designed fluidized-bed mild gasifier using the commercial CFD solver ANSYS\\/FLUENT. Eulerain-Eulerian method is employed to calculate both the primary phase (air) and secondary phase (coal

AKM Monayem Hossain Mazumder

2010-01-01

297

Microfluidics with aqueous two-phase systems.  

PubMed

An overview is given about research activities in which aqueous two phase systems (ATPSs) are utilized in microfluidic setups. ATPSs consist of two immiscible aqueous phases and have traditionally been used for the separation and purification of biological material such as proteins or cells. Microfluidic implementations of such schemes are usually based on a number of co-flowing streams of immiscible phases in a microchannel, thereby replacing the standard batch by flow-through processes. Some aspects of the stability of such flow patterns and the recovery of the phases at the channel exit are reviewed. Furthermore, the diffusive mass transfer and sample partitioning between the phases are discussed, and corresponding applications are highlighted. When diffusion is superposed by an applied electric field normal to the liquid/liquid interface, the transport processes are accelerated, and under specific conditions the interface acts as a size-selective filter for molecules. Finally, the activities involving droplet microflows of ATPSs are reviewed. By either forming ATPS droplets in an organic phase or a droplet of one aqueous phase inside the other, a range of applications has been demonstrated, extending from separation/purification schemes to the patterning of surfaces covered with cells. PMID:21897979

Hardt, Steffen; Hahn, Thomas

2012-02-01

298

Photolysis of oxyfluorfen in aqueous methanol.  

PubMed

Photolysis of oxyfluorfen, an herbicide of the nitrodiphenyl ether class, was studied in aqueous methanol under UV and sunlight. UV irradiation was carried out in a borosilicate glass photoreactor (containing 250 ppm oxyfluorfen in 50% aqueous methanol) equipped with a quartz filter and 125 watt mercury lamp (maximum output 254 nm) at 25 ± 1°C. Sunlight irradiation was conducted at 28 ± 1°C in borosilicate Erlenmeyer flasks containing 250 ppm oxyfluorfen in 50% aqueous methanol. The samples from both the irradiated conditions were withdrawn at a definite time interval and extracted to measure oxyfluorfen content by gas chromatography-flame ionization detector for rate study. The half-life values were 20 hours and 2.7 days under UV and sunlight exposure, respectively. Photolysis of oxyfluorfen yielded 13 photoproducts of which three were characterized by infrared spectrophotometer and (1)H NMR and (13)C NMR spectroscopy. The rest of the photoproducts were identified by gas chromatography-mass spectrometry (GC-MS) and thin layer chromatography (TLC). An ionization potential 70 eV was used for electron impact-mass spectrometry (EI-MS) and methane was used as reagent gas for chemical ionization-mass spectrometry (CI-MS). Two of the photoproducts were also synthesized for comparison. The main phototransformation pathways of oxyfluorfen involved nitro reduction, dechlorination, and hydrolysis as well as nucleophiles displacement reaction. PMID:23998303

Chakraborty, Subhasish K; Chakraborty, Savitri; Bhattacharyya, Anjan; Chowdhury, Ashim

2013-01-01

299

Mars Aqueous Processing System  

NASA Technical Reports Server (NTRS)

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 ore concentrate, which demonstrates that lunar-derived material can be used in a manner similar to conventional terrestrial iron. Metallic iron was also produced from the Mars soil simulant. The aluminum and magnesium oxide products produced by MAPS from lunar and Mars soil simulants exhibited excellent thermal stability, and were shown to be capable of use for refractory oxide structural materials, or insulation at temperatures far in excess of what could be achieved using unrefined soils. These materials exhibited the refractory characteristics needed to support iron casting and forming operations, as well as other thermal processing needs. Extraction residue samples contained up to 79 percent silica. Such samples were successfully fused into a glass that exhibited high light transmittance.

Berggren, Mark; Wilson, Cherie; Carrera, Stacy; Rose, Heather; Muscatello, Anthony; Kilgore, James; Zubrin, Robert

2012-01-01

300

Photochemical Oxidation of Aqueous ?-Pinene SOA with Fe  

NASA Astrophysics Data System (ADS)

Current atmospheric models, which largely utilize gas- and gas-particle reactions, have difficulty predicting the degree of oxidation of ambient organic-bearing particles, suggesting unidentified oxidation mechanisms. To account for these discrepancies, recent studies have shown that aqueous-phase oxidation chemistry occurring in cloud and fog droplets contributes to the formation and processing of organic aerosol. Given that organic-bearing particles have been shown to be hygroscopic at high relative humidity, and that known oxidant precursors (e.g. peroxides, nitrate, soluble iron) are common components of ambient particles, it has been suggested that aqueous particles are efficient media for aqueous oxidation chemistry, due to the higher concentrations of solutes as compared to cloud and fog droplets. The objective of this work is to investigate whether aqueous SOA can undergo oxidative reactions. Laboratory results conducted with an environmental chamber show that particles with water-soluble organics from ?-pinene ozonolysis, ammonium sulfate and iron, can be further oxidized in the presence of UV-B light under high relative humidity conditions. The effects of relative humidity and light on this aqueous aerosol processing mechanism will also be presented. These experimental results demonstrate that aqueous organic particles can undergo photochemically driven oxidative processing in the atmosphere when soluble iron or other OH precursors are present.

Wong, J. P.; Zhou, S.; Abbatt, J.

2013-12-01

301

Aromatization of Hantzsch 1,4-Dihydropyridines with Al(NO3)3·9H2O and\\/or Fe(NO3)3·9H2O in the Presence of Silica Sulfuric Acid Under Mild and Heterogeneous Conditions  

Microsoft Academic Search

A simple and convenient method for the aromatization of Hantzsch 1,4-dihydropyridines to the corresponding pyridines is achieved via combination of aluminum or ferric nitrates and silica sulfuric acid as environmentally friendly and novel oxidizing media. This oxidation was carried out in dichloromethane under heterogeneous conditions with good to excellent yields.

Arash Ghorbani-Choghamarani; Javad Zeinivand

2010-01-01

302

Aqueous chlorination of resorcinol  

USGS Publications Warehouse

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.

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

303

Aqueous photolysis of niclosamide  

USGS Publications Warehouse

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.

Graebing, P.W.; Chib, J.S.; Hubert, T.D.; Gingerich, W.H.

2004-01-01

304

ASSESSMENT OF LIQUID EMULSION MEMBRANE FOR CLEAN UP OF AQUEOUS WASTE EFFLUENTS FROM HAZARDOUS ELEMENTS  

SciTech Connect

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.

El-Reefy, Sohair A.; Selim, Y.T.; Hassan, M.A.; Aly, H.F.

2003-02-27

305

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)

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.

Etale, Anita; Tutu, Hlanganani; Drake, Deanne C.

2014-06-01

306

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...

307

ENCOAL Mild Coal Gasification Demonstration Project. Annual report, October 1993--September 1994  

SciTech Connect

ENCOAL Corporation, a wholly-owned subsidiary of SMC Mining Company (formerly Shell Mining Company, now owned by Zeigler Coal Holding Company), has completed the construction and start-up 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). The LFC technology uses a mild pyrolysis or mild gasification process which involves heating the coal under carefully controlled conditions. The process causes chemical changes in the feed coal in contrast to conventional drying, which leads only to physical changes. Wet subbituminous coal contains considerable water, and conventional drying processes physically remove some of this moisture, causing the heating value to increase. The deeper the coal is physically dried, the higher the heating value and the more the pore structure permanently collapses, preventing resorption of moisture. However, deeply dried Powder River Basin coals exhibit significant stability problems when dried by conventional thermal processes. The LFC process overcomes these stability problems by thermally altering the solid to create PDF and CDL. Several of the major objectives of the ENCOAL Project have now been achieved. The LFC Technology has been essentially demonstrated. Significant quantities of specification CDL have been produced from Buckskin coal. Plant operation in a production mode with respectable availability (approaching 90%) has been demonstrated.

NONE

1995-03-01

308

Patients with mild to moderate body dysmorphic disorder may benefit from rhinoplasty.  

PubMed

Body dysmorphic disorder (BDD) is one of the most common psychiatric conditions found in patients seeking cosmetic surgery. BDD is also a challenge for plastic surgeons because it is still an underdiagnosed mental disorder. The aims of this study were to prospectively investigate whether patients with mild to moderate BDD are suitable for rhinoplasty, and to assess BDD severity and patient satisfaction with the surgical outcome 1 year after the intervention. All women (n = 116) seeking rhinoplasty at a university hospital between September 2009 and August 2010 were recruited for the study and assessed for BDD. The final sample consisted of 31 patients aged 32 (standard deviation (SD), 10) years with mild to moderate BDD who underwent rhinoplasty. The participants were assessed preoperatively (baseline) and 1 year postoperatively with the Body Dysmorphic Disorder Examination (BDDE). Most patients (22/31, 71%) were of African descent. Socio-demographic variables and the extent of the nasal deformities had no effect on the severity of BDD symptoms and patient satisfaction with surgery outcome. At the 1-year postoperative follow-up, there was a significant decrease from baseline in BDDE scores and time spent by patients worrying about their appearance; 25 (25/31, 81%) patients experienced complete remission from BDD and 28 (28/31, 90%) were satisfied with the results of surgery. Rhinoplasty may be indicated in the treatment of female patients with mild to moderate BDD. PMID:24508222

Felix, Gabriel Almeida Arruda; de Brito, Maria José Azevedo; Nahas, Fabio Xerfan; Tavares, Hermano; Cordás, Táki Athanássios; Dini, Gal Moreira; Ferreira, Lydia Masako

2014-05-01

309

Scale-up of mild gasification to a process development unit  

SciTech Connect

The work performed during the second quarterly reporting period (February 21 through May 20, 1992) on the research program, Scale-Up of Mild Gasification to a Process Development Unit'' is presented in this report. The overall objective of this project is to develop the IGT Mild-Gasification (MILDGAS) process for near-term commercialization. The specific objectives of the program are to: (1) design, construct, and operate a 24-tons/day adiabatic process development unit (PDU) to obtain process performance data suitable for further design scaleup. (2) obtain large batches of coal-derived co-products for industrial evaluation. (3) prepare a detailed design of a demonstration unit. (4) develop technical and economic plans for commercialization of the MILDGAS process. The MILDGAS process is a continuous closed system for producing liquid and solid (char) co-products at mild operating conditions up to 50 psig and 1300[degrees]F. It is capable of processing a wide range of both eastern caking and western noncaking coals. The PDU to be constructed is comprised of a 2.5-ft ID adiabatic gasifier for the production of char, coal liquids, and gases; a thermal cracker for upgrading of the coal liquids; and a hot briquetting unit for the production of form coke and smokeless fuel briquettes. The facility will also incorporate support equipment for environmentally acceptable disposal of process waste.

Campbell, J.A.L.; Carty, R.H.; Saladin, N.; Foster, H.

1992-06-01

310

Mild chemical oxidation of reactive uranium for disposal or recovery  

SciTech Connect

Large quantities (thousands of drums) of waste uranium metal or alloyed metals as scrap or chips and turnings are generated annually in the DOE complex. The high surface areas of this waste renders it highly reactive with both air and moisture. Storage of the materials is hazardous and expensive, but most DOE sites are forced to store the waste, because no adequate treatment or recycle technology is available. Los Alamos National Laboratory (LANL) currently has over 200 55-gal drums of reactive uranium awaiting treatment or recovery. To address this problem, LANL has developed a process for the low-temperature conversion of waste uranium metal to uranium oxide. The basis of our technology is a mild solution oxidation using sodium hypochlorite (bleach). Divided uranium metal or alloys are excellent candidates for this type of oxidation because of their high chemical reactivity. uranium turnings react rapidly with dilute solutions of sodium hypochlorite to form an insoluble uranium (VI) oxide, UO{sub 2}(OH){sub 2}, as a finely divided yellow powder. The resulting powder is suitable for disposal after solidification or for recycle. Designs for a suitable reactor system for this process have been completed in the Waste Management Group at LANL. The skid-mounted mobile unit will be capable of treating up to 100 kg of metal or alloy per batch. This paper summarizes the details of the process, including formation and characterization of the uranium product, identification of process operating conditions, and reactor design. Included is a description of the steps for permitting the process.

Sauer, N.N.; Lussiez, G.

1994-12-31

311

Depression of Cortical Activity in Humans by Mild Hypercapnia  

PubMed Central

The effects of neural activity on cerebral hemodynamics underlie human brain imaging with functional magnetic resonance imaging and positron emission tomography. However, the threshold and characteristics of the converse effects, wherein the cerebral hemodynamic and metabolic milieu influence neural activity, remain unclear. We tested whether mild hypercapnia (5% CO2) decreases the magnetoencephalogram response to auditory pattern recognition and visual semantic tasks. Hypercapnia induced statistically significant decreases in event-related fields without affecting behavioral performance. Decreases were observed in early sensory components in both auditory and visual modalities as well as later cognitive components related to memory and language. Effects were distributed across cortical regions. Decreases were comparable in evoked versus spontaneous spectral power. Hypercapnia is commonly used with hemodynamic models to calibrate the blood oxygenation level-dependent response. Modifying model assumptions to incorporate the current findings produce a modest but measurable decrease in the estimated cerebral metabolic rate for oxygen change with activation. Because under normal conditions, low cerebral pH would arise when bloodflow is unable to keep pace with neuronal activity, the cortical depression observed here may reflect a homeostatic mechanism by which neuronal activity is adjusted to a level that can be sustained by available bloodflow. Animal studies suggest that these effects may be mediated by pH-modulating presynaptic adenosine receptors. Although the data is not clear, comparable changes in cortical pH to those induced here may occur during sleep apnea, sleep, and exercise. If so, these results suggest that such activities may in turn have generalized depressive effects on cortical activity. PMID:21500313

Thesen, Thomas; Leontiev, Oleg; Song, Tao; Dehghani, Nima; Hagler, Donald J; Huang, Mingxiong; Buxton, Richard; Halgren, Eric

2013-01-01

312

Depression of cortical activity in humans by mild hypercapnia.  

PubMed

The effects of neural activity on cerebral hemodynamics underlie human brain imaging with functional magnetic resonance imaging and positron emission tomography. However, the threshold and characteristics of the converse effects, wherein the cerebral hemodynamic and metabolic milieu influence neural activity, remain unclear. We tested whether mild hypercapnia (5% CO2 ) decreases the magnetoencephalogram response to auditory pattern recognition and visual semantic tasks. Hypercapnia induced statistically significant decreases in event-related fields without affecting behavioral performance. Decreases were observed in early sensory components in both auditory and visual modalities as well as later cognitive components related to memory and language. Effects were distributed across cortical regions. Decreases were comparable in evoked versus spontaneous spectral power. Hypercapnia is commonly used with hemodynamic models to calibrate the blood oxygenation level-dependent response. Modifying model assumptions to incorporate the current findings produce a modest but measurable decrease in the estimated cerebral metabolic rate for oxygen change with activation. Because under normal conditions, low cerebral pH would arise when bloodflow is unable to keep pace with neuronal activity, the cortical depression observed here may reflect a homeostatic mechanism by which neuronal activity is adjusted to a level that can be sustained by available bloodflow. Animal studies suggest that these effects may be mediated by pH-modulating presynaptic adenosine receptors. Although the data is not clear, comparable changes in cortical pH to those induced here may occur during sleep apnea, sleep, and exercise. If so, these results suggest that such activities may in turn have generalized depressive effects on cortical activity. PMID:21500313

Thesen, Thomas; Leontiev, Oleg; Song, Tao; Dehghani, Nima; Hagler, Donald J; Huang, Mingxiong; Buxton, Richard; Halgren, Eric

2012-03-01

313

[New aqueous humor drainage systems].  

PubMed

The use of drainage systems in glaucoma treatment progressively increase, mainly in case of failure of medical treatment and/or laser and/or trabeculectomy. They aimed to improve aqueous humor drainage through the trabecular meshwork. New drainage concepts are regularly proposed, either with biomaterial implants, inert or non absorbent, or with approaches to bypass trabecular resistance and facilitate aqueous humor outflow directly in Schlemm canal. The aim of this article is to present and discuss these new approaches. PMID:19515341

Robe-Collignon, N

2009-03-01

314

Viscosity-stabilized aqueous solutions  

SciTech Connect

Selected sulfur-containing compounds function as solution viscosity stabilizers in aqueous compositions of solid acrylamide polymers contain a redox couple or components which can produce a redox couple in the presence of the solution. The aqueous compositions are useful in post-primary oil recovery involving the use of thickened fluids as mobility buffers and mobility control agents. Specific examples are thiourea, 2-mercaptoethanol, and sodium n,n-dimethyldithiocarbamate. Improved resistance to thermal and oxidative degradation is obtained. 17 claims.

Bruning, D.D.

1982-03-02

315

All-aqueous multiphase microfluidics  

PubMed Central

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

Song, Yang; Sauret, Alban; Cheung Shum, Ho

2013-01-01

316

Photochemistry of aqueous pyruvic acid  

PubMed Central

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 ?-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. PMID:23821751

Griffith, Elizabeth C.; Carpenter, Barry K.; Shoemaker, Richard K.; Vaida, Veronica

2013-01-01

317

Dissolution of K-feldspar at CO2-saturated conditions  

NASA Astrophysics Data System (ADS)

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 strong acids and rates measured in unbuffered aqueous solution. However, our rates are slightly slower than those predicted based solely on pH, a fact that we preliminary attribute to our choice to pre-react the mineral and fluid before the CO2 injection. The exact cause of this effect is still under investigation.

Rosenqvist, Jörgen; Kilpatrick, Andrew D.; Yardley, Bruce W. D.; Rochelle, Christopher A.

2014-05-01

318

Adsorption of dysprosium ions on activated charcoal from aqueous solutions  

Microsoft Academic Search

The adsorption of dysprosium ions onto activated charcoal from aqueous solution has been investigated in relation to pertinent variables, such as shaking time, pH, concentration of dysprosium ions, and temperature. The conditions leading to maximum adsorption have been established. The adsorption of dysprosium ions obeys the Langmuir and the Dubinin-Radushkevich isotherm equations. Thermodynamic quantities, namely AH and AS, have been

Riaz Qadeer; Javed Hanif

1995-01-01

319

Fenton chemistry at aqueous interfaces  

PubMed Central

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 ?s. 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

Enami, Shinichi; Sakamoto, Yosuke; Colussi, Agustín J.

2014-01-01

320

Could mild hypoxia impair pilot decision making in emergencies?  

PubMed

The decreased pressure in the cabin of a pressurised aircraft (typically equivalent to ~8000 ft) reduces the oxygen level so that the blood oxygen saturation of all occupants falls from >97% (normoxia) at sea-level to below 92% (mild hypoxia). Although exposure to mild hypoxia does not affect well-learned cognitive and motor performance of aircrew, it has been proposed that it can affect the performance of some complex cognitive performance tasks involving multiple demands typical of emergency tasks that may have to be performed by pilots. In order to simulate some of these complex cognitive demands, 25 student volunteers participated in an experiment which assessed performance of complex logical reasoning and and multiple memory tasks before and after 2 hours of exposure to normoxia and mild hypoxia. Performance for the more difficult components of the complex reasoning task, especially involving conflict decisions, were marginally significantly degraded by mild hypoxia. Since the effects were only marginally significant future studies should investigate the effects of mild hypoxia on more subtle complex decision-making tasks. PMID:22316722

Legg, Stephen; Hill, Stephen; Mundel, Toby; Gilbey, Andrew; Schlader, Zac; Raman, Aaron

2012-01-01

321

Mild Lafora disease: Clinical, neurophysiologic, and genetic findings.  

PubMed

We report clinical, neurophysiologic, and genetic features of an Italian series of patients with Lafora disease (LD) to identify distinguishing features of those with a slowly progressive course. Twenty-three patients with LD (17 female; 6 male) were recruited. Mean age (± SD) at the disease onset was 14.5 ± 3.9 years and mean follow-up duration was 13.2 ± 8.0 years. NHLRC1 mutations were detected in 18 patients; EPM2A mutations were identified in 5. Patients who maintained >10 years gait autonomy were labeled as "mild" and were compared with the remaining LD patients with a typical course. Six of 23 patients were mild and presented significantly delay in the age at onset, lower neurologic disability score at 4 years after the onset, less severe seizure phenotype, lower probability of showing both photoparoxysmal response on electroencephalography (EEG) and giant somatosensory evoked potentials, as compared to patients with typical LD. However, in both mild and typical LD patients, EEG showed disorganization of background activity and frequent epileptiform abnormalities. Mild LD patients had NHLRC1 mutations and five of six carried homozygous or compound heterozygous D146N mutation. This mutation was found in none of the patients with typical LD. The occurrence of specific NHLRC1 mutations in patients with mild LD should be taken into account in clinical practice for appropriate management and counseling. PMID:25270369

Ferlazzo, Edoardo; Canafoglia, Laura; Michelucci, Roberto; Gambardella, Antonio; Gennaro, Elena; Pasini, Elena; Riguzzi, Patrizia; Plasmati, Rosaria; Volpi, Lilia; Labate, Angelo; Gasparini, Sara; Villani, Flavio; Casazza, Marina; Viri, Maurizio; Zara, Federico; Minassian, Berge A; Turnbull, Julie; Serratosa, Jose M; Guerrero-López, Rosa; Franceschetti, Silvana; Aguglia, Umberto

2014-12-01

322

Activity restriction in mild COPD: a challenging clinical problem.  

PubMed

Dyspnea, exercise intolerance, and activity restriction are already apparent in mild chronic obstructive pulmonary disease (COPD). However, patients may not seek medical help until their symptoms become troublesome and persistent and significant respiratory impairment is already present; as a consequence, further sustained physical inactivity may contribute to disease progression. Ventilatory and gas exchange impairment, cardiac dysfunction, and skeletal muscle dysfunction are present to a variable degree in patients with mild COPD, and collectively may contribute to exercise intolerance. As such, there is increasing interest in evaluating exercise tolerance and physical activity in symptomatic patients with COPD who have mild airway obstruction, as defined by spirometry. Simple questionnaires, eg, the modified British Medical Research Council dyspnea scale and the COPD Assessment Test, or exercise tests, eg, the 6-minute or incremental and endurance exercise tests can be used to assess exercise performance and functional status. Pedometers and accelerometers are used to evaluate physical activity, and endurance tests (cycle or treadmill) using constant work rate protocols are used to assess the effects of interventions such as pulmonary rehabilitation. In addition, alternative outcome measurements, such as tests of small airway dysfunction and laboratory-based exercise tests, are used to measure the extent of physiological impairment in individuals with persistent dyspnea. This review describes the mechanisms of exercise limitation in patients with mild COPD and the interventions that can potentially improve exercise tolerance. Also discussed are the benefits of pulmonary rehabilitation and the potential role of pharmacologic treatment in symptomatic patients with mild COPD. PMID:24940054

O'Donnell, Denis E; Gebke, Kevin B

2014-01-01

323

Functional disorganization of small-world brain networks in mild Alzheimer's Disease and amnestic Mild Cognitive Impairment: an EEG study using Relative Wavelet Entropy (RWE).  

PubMed

Previous neuroscientific findings have linked Alzheimer's Disease (AD) with less efficient information processing and brain network disorganization. However, pathological alterations of the brain networks during the preclinical phase of amnestic Mild Cognitive Impairment (aMCI) remain largely unknown. The present study aimed at comparing patterns of the detection of functional disorganization in MCI relative to Mild Dementia (MD). Participants consisted of 23 cognitively healthy adults, 17 aMCI and 24 mild AD patients who underwent electroencephalographic (EEG) data acquisition during a resting-state condition. Synchronization analysis through the Orthogonal Discrete Wavelet Transform (ODWT), and directional brain network analysis were applied on the EEG data. This computational model was performed for networks that have the same number of edges (N = 500, 600, 700, 800 edges) across all participants and groups (fixed density values). All groups exhibited a small-world (SW) brain architecture. However, we found a significant reduction in the SW brain architecture in both aMCI and MD patients relative to the group of Healthy controls. This functional disorganization was also correlated with the participant's generic cognitive status. The deterioration of the network's organization was caused mainly by deficient local information processing as quantified by the mean cluster coefficient value. Functional hubs were identified through the normalized betweenness centrality metric. Analysis of the local characteristics showed relative hub preservation even with statistically significant reduced strength. Compensatory phenomena were also evident through the formation of additional hubs on left frontal and parietal regions. Our results indicate a declined functional network organization even during the prodromal phase. Degeneration is evident even in the preclinical phase and coexists with transient network reorganization due to compensation. PMID:25206333

Frantzidis, Christos A; Vivas, Ana B; Tsolaki, Anthoula; Klados, Manousos A; Tsolaki, Magda; Bamidis, Panagiotis D

2014-01-01

324

A mild, ferrocene-catalyzed C-H imidation of (hetero)arenes.  

PubMed

A simple method for direct C-H imidation is reported using a new perester-based self-immolating reagent and a base-metal catalyst. The succinimide products obtained can be easily deprotected in situ (if desired) to reveal the corresponding anilines directly. The scope of the reaction is broad, the conditions are extremely mild, and the reaction is tolerant of oxidizable and acid-labile functionality, multiple heteroatoms, and aryl iodides. Mechanistic studies indicate that ferrocene (Cp2Fe) plays the role of an electron shuttle in the decomposition of the perester reagent, delivering a succinimidyl radical ready to add to an aromatic system. PMID:24654983

Foo, Klement; Sella, Eran; Thomé, Isabelle; Eastgate, Martin D; Baran, Phil S

2014-04-01

325

Johnson - Cook Strength Models for Mild and DP 590 Steels  

SciTech Connect

Automotive steels, Mild and Dual Phase590 (DP590) are characterized in tension at room temperature, using the quasi-static and split Hopkinson bar techniques at various strain rates ranging from {approx}10-3/s to {approx}1800/s. Tension stress-strain data for both the steels are analyzed to determine the Johnson-Cook Strength model constants, J-C strength model constants for mild steel are A=217 MPa, B = 234 MPa, n = 0.643 and C = 0.076 and for DP590 steel are A = 430 MPa, B = 824 MPa, n = 0.510 and C = 0.017. Higher value of strain rate sensitivity constant C for mild steel (0.076) compared to DP 590 (0.017) is also reflected in the stress- strain data at various strain rates.

Vedantam, K.; Brar, N. S. [Mechanical and Aerospace Engineering and Research Institute, University of Dayton, Dayton, OH 45469-0182 (United States); Bajaj, D. [University of Maryland, Baltimore County, Baltimore, MD 21250 (United States); Hill, S. [University of Dayton Research Institute, University of Dayton, OH 45460-0135 (United States)

2006-07-28

326

Electroresponsive aqueous silk protein as "smart" mechanical damping fluid.  

PubMed

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

Jose, Rod R; Elia, Roberto; Tien, Lee W; Kaplan, David L

2014-05-14

327

Blow-up in multidimensional aggregation equations with mildly singular interaction kernels  

NASA Astrophysics Data System (ADS)

We consider the multidimensional aggregation equation ut - ?· (u?K * u) = 0 in which the radially symmetric attractive interaction kernel has a mild singularity at the origin (Lipschitz or better). In the case of bounded initial data, finite time singularity has been proved for kernels with a Lipschitz point at the origin (Bertozzi and Laurent 2007 Commun. Math. Sci. 274 717-35), whereas for C2 kernels there is no finite-time blow-up. We prove, under mild monotonicity assumptions on the kernel K, that the Osgood condition for well-posedness of the ODE characteristics determines global in time well-posedness of the PDE with compactly supported bounded nonnegative initial data. When the Osgood condition is violated, we present a new proof of finite time blow-up that extends previous results, requiring radially symmetric data, to general bounded, compactly supported nonnegative initial data without symmetry. We also present a new analysis of radially symmetric solutions under less strict monotonicity conditions. Finally, we conclude with a discussion of similarity solutions for the case K(x) = |x| and some open problems. This paper is published as part of a collection in honour of Todd Dupont's 65th birthday.

Bertozzi, Andrea L.; Carrillo, José A.; Laurent, Thomas

2009-03-01

328

Converting sugars to sugar alcohols by aqueous phase catalytic hydrogenation  

DOEpatents

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.

Elliott, Douglas C. (Richland, WA); Werpy, Todd A. (West Richland, WA); Wang, Yong (Richland, WA); Frye, Jr., John G. (Richland, WA)

2003-05-27

329

Electrooxidation of Aqueous p Methoxyphenol on Lead Oxide Electrodes  

Microsoft Academic Search

Oxidation of p-methoxyphenol (pmp) in aqueous solution on bismuth-doped lead oxide was studied, and the effects of the initial pmp concentration, applied potential and hydrodynamic conditions upon the oxidation rate were identified. Under all conditions studied, the concentration decay of pmp during electrooxidation follows first—order reaction kinetics. Through analysis of rotating ring-disc currents, the faradaic efficiencies for oxidation at various

C. Borrás; P. Rodríguez; T. Laredo; J. Mostany; B. R. Scharifker

2004-01-01

330

Recent Analysis of UCAPs in Mild Hybrids (Presentation)  

SciTech Connect

This report presents the analysis of ultracapacitors for mild/moderate hybrid electric vehicle (HEV) performance. The objectives of this report are to: (1) review the fuel economy improvement trends of today's HEVs with respect to degree of hybridization; (2) perform analysis to see the extent of fuel economy improvement possible with various strategies in mild/moderate HEVs, with no engine downsizing, using either batteries or ultracapacitors; (3) identify energy requirements of various driving events/functions--what matches a limited ucap's energy; and (4) discuss potential roles for high-voltage ultracapacitors in HEVs, if any.

Pesaran, A.; Gonder, J.

2006-05-01

331

Modeling a set of heavy oil aqueous pyrolysis experiments  

SciTech Connect

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.

Thorsness, C.B.; Reynolds, J.G.

1996-11-01

332

Solubility Measurements of Crystalline NiO in Aqueous Solution as a Function of Temperature and pH  

Microsoft Academic Search

Results of solubility experiments involving crystalline nickel oxide (bunsenite) in aqueous solutions are reported as functions\\u000a of temperature (0 to 350?°C) and pH at pressures slightly exceeding (with one exception) saturation vapor pressure. These\\u000a experiments were carried out in either flow-through reactors or a hydrogen-electrode concentration cell for mildly acidic\\u000a to near neutral pH solutions. The results were treated successfully

Donald A. Palmer; Pascale Bénézeth; Caibin Xiao; David J. Wesolowski; Lawrence M. Anovitz

2011-01-01

333

Aqueous Alteration of Basalts: Earth, Moon, and Mars  

NASA Technical Reports Server (NTRS)

The geologic processes responsible for aqueous alteration of basaltic materials on Mars are modeled beginning with our knowledge of analog processes on Earth, i.e., characterization of elemental and mineralogical compositions of terrestrial environments where the alteration and weathering pathways related to aqueous activity are better understood. A key ingredient to successful modeling of aqueous processes on Mars is identification of phases that have formed by those processes. The purpose of this paper is to describe what is known about the elemental and mineralogical composition of aqueous alteration products of basaltic materials on Mars and their implications for specific aqueous environments based upon our knowledge of terrestrial systems. Although aqueous alteration has not occurred on the Moon, it is crucial to understand the behaviors of basaltic materials exposed to aqueous environments in support of human exploration to the Moon over the next two decades. Several methods or indices have been used to evaluate the extent of basalt alteration/weathering based upon measurements made at Mars by the Mars Exploration Rover (MER) Moessbauer and Alpha Particle X-Ray Spectrometers. The Mineralogical Alteration Index (MAI) is based upon the percentage of total Fe (Fe(sub T)) present as Fe(3+) in alteration products (Morris et al., 2006). A second method is the evaluation of compositional trends to determine the extent to which elements have been removed from the host rock and the likely formation of secondary phases (Nesbitt and Young, 1992; Ming et al., 2007). Most of the basalts that have been altered by aqueous processes at the two MER landing sites in Gusev crater and on Meridiani Planum have not undergone extensive leaching in an open hydrolytic system with the exception of an outcrop in the Columbia Hills. The extent of aqueous alteration however ranges from relatively unaltered to pervasively altered materials. Several experimental studies have focused upon 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.

Ming, Douglas W.

2007-01-01

334

Synergistic effect of mixed cationic and anionic surfactants on the corrosion inhibitor behavior of mild steel in 3.5% NaCl  

NASA Astrophysics Data System (ADS)

The corrosion inhibition characteristics of cation-rich and anion-rich catanionic mixtures of cetyltrimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), as corrosion inhibitor of mild steel (MS), in aqueous solution of 3.5% NaCl were investigated using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and scanning electron microscopy (SEM). Solutions of CTAB/SDS mixtures showed more appropriate inhibition properties compared to the solutions of the individual surfactants, due to strong adsorption on the metal surface and formation of a protective film. Potentiodynamic polarization investigations indicated that the inhibitors studied were mixed type inhibitors. Adsorption of the inhibitors on the mild steel surface obeyed the Flory-Huggins adsorption isotherm. Furthermore, the values of the adsorption free energy (?G°ads) in both mixtures decreased compared with a single surfactant which is attributed to stronger interactions in mixtures.

Javadian, Soheila; Yousefi, Ali; Neshati, Jaber

2013-11-01

335

A Study on the Aqueous Formation of Secondary Organic Aerosols  

NASA Astrophysics Data System (ADS)

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.

Sinclair, K.; Tsigaridis, K.

2013-12-01

336

Aqueous-phase source of formic acid in clouds  

NASA Technical Reports Server (NTRS)

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.

Chameides, W. L.; Davis, D. D.

1983-01-01

337

NMR Studies on the Aqueous Phase Photochemical Degradation of TNT  

SciTech Connect

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.

Thorn, Kevin A.; Cox, Larry G.

2008-04-06

338

Photorelease of phosphates: Mild methods for protecting phosphate derivatives  

PubMed Central

Summary We have developed a new photoremovable protecting group for caging phosphates in the near UV. Diethyl 2-(4-hydroxy-1-naphthyl)-2-oxoethyl phosphate (14a) quantitatively releases diethyl phosphate upon irradiation in aq MeOH or aq MeCN at 350 nm, with quantum efficiencies ranging from 0.021 to 0.067 depending on the solvent composition. The deprotection reactions originate from the triplet excited state, are robust under ambient conditions and can be carried on to 100% conversion. Similar results were found with diethyl 2-(4-methoxy-1-naphthyl)-2-oxoethyl phosphate (14b), although it was significantly less efficient compared with 14a. A key step in the deprotection reaction in aq MeOH is considered to be a Favorskii rearrangement of the naphthyl ketone motif of 14a,b to naphthylacetate esters 25 and 26. Disruption of the ketone-naphthyl ring conjugation significantly shifts the photoproduct absorption away from the effective incident wavelength for decaging of 14, driving the reaction to completion. The Favorskii rearrangement does not occur in aqueous acetonitrile although diethyl phosphate is released. Other substitution patterns on the naphthyl or quinolin-5-yl core, such as the 2,6-naphthyl 10 or 8-benzyloxyquinolin-5-yl 24 platforms, also do not rearrange by aryl migration upon photolysis and, therefore, do not proceed to completion. The 2,6-naphthyl ketone platform instead remains intact whereas the quinolin-5-yl ketone fragments to a much more complex, highly absorbing reaction mixture that competes for the incident light. PMID:25246963

Senadheera, Sanjeewa N; Yousef, Abraham L

2014-01-01

339

Aqueous Corrosion Rates for Waste Package Materials  

SciTech Connect

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.

S. Arthur

2004-10-08

340

Limiting iron availability confers neuroprotection from chronic mild carbon monoxide exposure in the developing auditory system of the rat.  

PubMed

Iron deficiency and chronic mild carbon monoxide (CO) exposure are nutritional and environmental problems that can be experienced simultaneously. We examined the effects of chronic mild CO exposure and iron availability on auditory development in the rat. We propose that chronic mild CO exposure creates an oxidative stress condition that impairs the spiral ganglion neurons. The CO-exposed rat pups had decreased neurofilament proteins and increased copper, zinc-superoxide dismutase (SOD1) in the spiral ganglion neurons. We conclude that the increased amount of SOD1 causes an increase in hydrogen peroxide production that allows the Fenton reaction to occur. This reaction uses both iron and hydrogen peroxide to generate hydroxyl radicals and leads to the development of oxidative stress that impairs neuronal integrity. However, rat pups with decreased iron and CO exposure (ARIDCO) exhibited in their cochlea an up-regulation of transferrin, whereas their expression of neurofilament proteins and SOD1 were similar to control. Consequently, reduced iron availability and the normal expression of SOD1 do not promote oxidative stress in the cochlea. By using basal c-Fos expression as a marker for cellular activation we found a significant reduction in c-Fos expression in the central nucleus of the inferior colliculus in iron-adequate rat pups exposed to CO. By contrast, rather than being reduced, c-Fos expression in the ARIDCO group is the same as for controls. We conclude that the cochlea of rat pups with normal iron availability is selectively affected by mild CO exposure, causing a chronic oxidative stress, whereas limiting iron availability ameliorates the effect caused by mild CO exposure by averting conditions that facilitate oxidative stress. PMID:15880490

Webber, Douglas S; Lopez, Ivan; Korsak, Rose A; Hirota, Sean; Acuna, Dora; Edmond, John

2005-06-01

341

Polyelectrolyte brushes: a novel stable lubrication system in aqueous conditions.  

PubMed

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

Kobayashi, Motoyasu; Terada, Masami; Takahara, Atsushi

2012-01-01

342

Aqueous slurries of carbonaceous materials  

SciTech Connect

Aqueous carbonaceous slurries having reduced viscosity, a stabilized network of carbonaceous material in water and improved pumpability are obtained by having present a salt of naphthalenesulfonic acid formaldehyde condensate and at least one water soluble polymer selected from the group consisting of sodium alginate, guar gum, locust bean gum, carboxymethylhydroxypropyl guar gum, hydroxypropyl guar gum and guarpak guar gum. For example, a mixture of 96.8% by weight of ammonium naphthalenesulfonic acid formaldehyde condensate and 3.2% by weight of sodium alginate can be added to an aqueous coal slurry in an amount of 0.31% by weight of the slurry.

Schick, M.J.; Knitter, K.A.

1984-03-13

343

Teaching Library Skills to Students with Mild and Moderate Handicaps.  

ERIC Educational Resources Information Center

A direct instruction model is applied to the teaching of library skills to students with mild/moderate handicaps. The model involves determining students' skill levels, setting objectives, providing instruction, and monitoring student progress. A team approach is recommended, involving the library media specialist and the special education…

Wesson, Caren L.; Keefe, Margaret

1989-01-01

344

Corrosion inhibition of mild steel by aerobic biofilm  

Microsoft Academic Search

Mild steel electrodes were incubated in phosphate-buffered basal salt solution (BSS) having two different aerobic bacteria, viz. Pseudomonas alcaligenes and Pseudomonas cichorii. In the medium containing P. cichorii, significant reduction in the corrosion rate was observed due to the surface reaction leading to the formation of corrosion inhibiting bacterial biofilm. With a view to understand the mechanism of microbially influenced

Shobhana Chongdar; G. Gunasekaran; Pradeep Kumar

2005-01-01

345

Working Memory in Mild Alzheimer's Disease and Early Parkinson's Disease  

E-print Network

Working Memory in Mild Alzheimer's Disease and Early Parkinson's Disease Elizabeth A. Kensinger of Technology Alzheimer's disease (AD) and Parkinson's disease (PD) impair working memory (WM). It is unclear an expanding interest in how neurological diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD

Corkin, Suzanne

346

Counting Ability of Moderately and Mildly Handicapped Children.  

ERIC Educational Resources Information Center

The study examined basic counting competencies, difficulties, skill progressions, and variation among 36 moderately retarded and 64 mildly retarded students (ages 5-14). Quantitative and qualitative analyses indicated deficiencies in basic counting competencies and systematic oral- and object-counting errors. Striking individual differences in…

Baroody, Arthur J.

1986-01-01

347

Mild cognitive impairment: hope for stability, plan for progression.  

PubMed

Mild cognitive impairment (MCI) is a common heterogeneous syndrome that in some cases is transitional between normal age-related cognitive changes and dementia. Identifying it early may lead to prompt recognition of reversible causes and allows for timely future planning. This article describes definitions of MCI and its evaluation, differential diagnosis, and management. PMID:23208990

Patel, Birju B; Holland, N Wilson

2012-12-01

348

Classwide Peer Tutoring with Mildly Handicapped High School Students.  

ERIC Educational Resources Information Center

Fourteen mildly handicapped (learning-disabled or behavior-disordered) and 36 nondisabled students in grade 10 social studies classrooms participated in a classwide peer tutoring program. Performance on weekly tests was significantly improved; 60 percent of all students earned "A" grades, and failing grades were virtually eliminated. (Author/JDD)

Maheady, Larry; And Others

1988-01-01

349

Predicting Alzheimer dementia in mild cognitive impairment patients  

Microsoft Academic Search

A correct clinical diagnosis in the early stage of Alzheimer disease is not only of importance given the current available treatment with acetylcholine esterase inhibitors, but would be the basis for disease-modifying therapy slowing down or arresting the degenerative process. Moreover, in the last years, several efforts have been made to determine if a patient with mild cognitive impairment has

Barbara Borroni; Monica Di Luca; Alessandro Padovani

2006-01-01

350

ORIGINAL CONTRIBUTION Mediterranean Diet and Mild Cognitive Impairment  

E-print Network

ORIGINAL CONTRIBUTION Mediterranean Diet and Mild Cognitive Impairment Nikolaos Scarmeas, MD Background: Higher adherence to the Mediterranean diet (MeDi) may protect from Alzheimer disease (AD to AD. We recently demonstrated that higher adherence to the Mediterranean diet (MeDi) (a diet

351

Mild traumatic brain injury: a risk factor for neurodegeneration  

Microsoft Academic Search

ABSTRACT: Recently, it has become clear that head trauma can lead to a progressive neurodegeneration known as chronic traumatic encephalopathy. Although the medical literature also implicates head trauma as a risk factor for Alzheimer's disease, these findings are predominantly based on clinical diagnostic criteria that lack specificity. The dementia that follows head injuries or repetitive mild trauma may be caused

Brandon E Gavett; Robert A Stern; Robert C Cantu; Christopher J Nowinski; Ann C McKee

2010-01-01

352

Mild Intellectual Deficits in a Child with 49,XXXXY.  

ERIC Educational Resources Information Center

Although most males with a 49,XXXXY karyotype will have significant mental retardation, the case of an affected boy having mild-cognitive and motor delays and age-appropriate adaptive skills at 59 months is presented. Guarded optimism may be justified in affected males demonstrating close to or age-appropriate developmental skills through early…

Hersh, Joseph H.; And Others

1988-01-01

353

“Good Old Days” Bias Following Mild Traumatic Brain Injury  

Microsoft Academic Search

A small percentage of people with a mild traumatic brain injury (MTBI) report persistent symptoms and problems many months or even years following injury. Preliminary research suggests that people who sustain an injury often underestimate past problems (i.e., “good old days” bias), which can impact their perceived level of current problems and recovery. The purpose of this study was to

Grant L. Iverson; Rael T. Lange; Brian L. Brooks; V. Lynn Ashton Rennison

2010-01-01

354

Verbal Working Memory in Children with Mild Intellectual Disabilities  

ERIC Educational Resources Information Center

Background: Previous research into working memory of individuals with intellectual disabilities (ID) has established clear deficits. The current study examined working memory in children with mild ID (IQ 55-85) within the framework of the Baddeley model, fractionating working memory into a central executive and two slave systems, the phonological…

Van der Molen, M. J.; Van Luit, J. E. H.; Jongmans, M. J.; Van der Molen, M. W.

2007-01-01

355

Profound Retrograde Amnesia Following Mild Head Injury: Organic or Functional?  

Microsoft Academic Search

This paper describes a 56 year old female patient (JJ) who suffered a minor head injury at work and presented with profound retrograde amnesia for both public events and autobiographical material spanning her entire life. In addition, she complained of word-finding difficulties and anterograde memory impairment and neuropsychological assessment found evidence of mild executive dysfunction. Neurological investigations (CT and EEG)

Sarah Mackenzie Ross

2000-01-01

356

Numerical Magnitude Processing in Children with Mild Intellectual Disabilities  

ERIC Educational Resources Information Center

The present study investigated numerical magnitude processing in children with mild intellectual disabilities (MID) and examined whether these children have difficulties in the ability to represent numerical magnitudes and/or difficulties in the ability to access numerical magnitudes from formal symbols. We compared the performance of 26 children…

Brankaer, Carmen; Ghesquiere, Pol; De Smedt, Bert

2011-01-01

357

Consumer attitudes towards hypoallergenic apples that alleviate mild apple allergy  

Microsoft Academic Search

The development of genetically modified (GM) foods with benefits for consumers may be more acceptable than GM foods with benefits that accrue to industry or producers. The Santana apple is a novel hypoallergenic product suitable for many apple allergic consumers with mild symptomology. The Santana also needs fewer pesticides to be applied in production. A survey was conducted among consumers

Martijn F. Schenk; Marinus P. van der Maas; Marinus J. M. Smulders; Luud J. W. J. Gilissen; Arnout R. H. Fischer; Ivo A. van der Lans; Evert Jacobsen; Lynn J. Frewer

2011-01-01

358

Use of Lithium Hexafluoroisopropoxide as a Mild Base for  

E-print Network

Use of Lithium Hexafluoroisopropoxide as a Mild Base for Horner-Wadsworth-Emmons Olefination The weak base lithium 1,1,1,3,3,3-hexafluoroisopropoxide (LiHFI) is shown to be highly effective utility of fluorinated alkoxides as bases for intermolecular HWE (1) (a) Horner, L.; Hoffmann, H.; Wippel

359

Surgical treatment of asymptomatic and mildly symptomatic mitral regurgitation  

Microsoft Academic Search

Objective: The purpose of this study was to review the risk-benefit ratio of mitral valve repair in patients with severe mitral regurgitation and no or mild symptoms.Methods: From January 1989 to December 1994, 584 patients were operated on for mitral regurgitation. Of these, 175 patients were in New York Heart Association class I or II with grade 3 to 4

Miguel Sousa Uva; Gilles Dreyfus; Giuseppe Rescigno; Nadji al Aile; Roberto Mascagni; Mauro La Marra; Fréderic Pouillart; Shirish Pargaonkar; Evelyne Palsky; Radwan Raffoul; Marcio Scorsin; Giorgio Noera; Arrigo Lessana

1996-01-01

360

Congenital Syndromes and Mildly Handicapped Students: Implications for Special Educators.  

ERIC Educational Resources Information Center

Many learning disabilities or cases of mild retardation are due to medically diagnosable, congenital syndromes, such as fetal alcohol syndrome, sex chromosome abnormalities, multiple anomaly syndromes, phenylketonuria, and Tourette Syndrome. These syndromes are discussed, and suggestions are given for special education management. (Author/JDD)

Smith, Sandra M.

1989-01-01

361

Directed forgetting of autobiographical memory in mild Alzheimer's disease  

Microsoft Academic Search

Using the autobiographical directed forgetting method (Barnier et al., 2007), the present paper addressed the intentional inhibitory processes of episodic and semantic autobiographical memory in Alzheimer's disease (AD). Mild AD patients and healthy elderly people were instructed to either forget or to continue remembering previously generated autobiographical events. In a later recall test they were asked to reconstruct the early-generated

Mohamad El Haj; Virginie Postal; Didier Le Gall; Philippe Allain

2011-01-01

362

Prognostic factors in unintentional mild carbon monoxide poisoning  

Microsoft Academic Search

Objectives: To identify early predictors of recovery from mild carbon monoxide poisoning, and to search for qualitative interactions between subsets of patients and treatment effects. Design and setting: Inception cohort study from a 4-year, randomised, controlled trial, which compared normobaric oxygen therapy to the combination of normobaric plus hyperbaric oxygen therapy in 307 patients. Study was conducted at a hyperbaric

Djillali Annane; Sylvie Chevret; Marie Jars-Guincestre; Patrick Chillet; David Elkharrat; Philippe Gajdos; Jean Raphael

2001-01-01

363

Olfactory function after mild head injury in children.  

PubMed

Olfactory impairment has been shown to be linked to head injury. In addition, it is believed that measurement of olfactory function after head trauma represents a sensitive tool for measuring frontal brain damage. Aim of the study was to evaluate the effect of mild head trauma in children on olfactory function over a time period of up to 1 year after head trauma. The olfactory function of 114 children who suffered mild head trauma according to the Glasgow Coma Scale was assessed 3 times with an interval of 4 months. In addition, healthy, age-matched controls were tested for comparison of olfactory function. Patients scored significantly lower on the odor threshold test compared to the control group-but still within normal range. Between the 2 groups, no difference was found for suprathreshold testing. Neither olfactory threshold scores nor olfactory discrimination scores changed significantly over the study period of 1 year. This data prove an impact of mild head trauma on olfactory function of children. It seems unlikely that children who suffered mild head trauma will become hyposmic or anosmic. PMID:24554732

Schriever, Valentin A; Studt, Friederike; Smitka, Martin; Grosser, Kay; Hummel, Thomas

2014-05-01

364

Cognitive vulnerability in moderate, mild, and low seasonality.  

PubMed

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. PMID:22134455

Rohan, Kelly J; Nillni, Yael I; Mahon, Jennifer N; Roecklein, Kathryn A; Sitnikov, Lilya; Haaga, David A F

2011-12-01

365

Care Partner Responses to the Onset of Mild Cognitive Impairment  

ERIC Educational Resources Information Center

Purpose: We examined characteristics, responses, and psychological well-being of care partners who support and assist older adults recently diagnosed with mild cognitive impairment (MCI). Design and Methods: Based on a sample of 106 care partners of community residents diagnosed with MCI at memory clinics, we conducted face-to-face interviews…

Blieszner, Rosemary; Roberto, Karen A.

2010-01-01

366

Promoting Intensive Socialization of Mildly Retarded Within an Institution.  

ERIC Educational Resources Information Center

Eight papers report on the project at Austin State School, funded by a Hospital Improvement (HIP) grant, which used a multidisciplinary team to implement socialization programs for institutionalized mildly retarded persons exhibiting socially inept behavior. Two papers consider social rehabilitation and the task of trying to move residents out…

Graebner, Oliver E.; And Others

367

Six Postschool Case Studies of Mildly Learning Handicapped Young Adults.  

ERIC Educational Resources Information Center

Six mildly learning-handicapped young adults were observed for one year following graduation from high school. All six floundered from job to job and from class to class at a community college. They expressed discontent and frustration with their present situation, but were unable to plan realistically for the future. (Author/JDD)

Zetlin, Andrea G.; Hosseini, Ashraf

1989-01-01

368

Human Capability, Mild Perfectionism and Thickened Educational Praxis  

ERIC Educational Resources Information Center

This paper argues for a mild perfectionism in applying Amartya Sen's capability approach for an education transformative of student agency and well-being. Key to the paper is the significance of education as a process of being and becoming in the future, and education's fundamental objective of a positively changed human being. The capability…

Walker, Melanie

2008-01-01

369

Socially Assistive Robotics for Stroke and Mild TBI Rehabilitation  

E-print Network

recovery after stroke and mild traumatic brain injury. Our approach is original and promising- operative cardiac care, post-stroke rehabilitation, traumatic brain injury, and obesity mitigation. Intense neurorehabilitation from stroke, as well as unilateral brain damage from traumatic brain injury, tumors affecting arm

Mataric, Maja J.

370

Targeting norepinephrine in mild cognitive impairment and Alzheimer's disease  

PubMed Central

The Alzheimer's disease (AD) epidemic is a looming crisis, with an urgent need for new therapies to delay or prevent symptom onset and progression. There is growing awareness that clinical trials must target stage-appropriate pathophysiological mechanisms to effectively develop disease-modifying treatments. Advances in AD biomarker research have demonstrated changes in amyloid-beta (A?), brain metabolism and other pathophysiologies prior to the onset of memory loss, with some markers possibly changing one or two decades earlier. These findings suggest that amyloid-based therapies would optimally be targeted at the earliest clinically detectable stage (such as mild cognitive impairment (MCI)) or before. Postmortem data indicate that tau lesions in the locus coeruleus (LC), the primary source of subcortical norepinephrine (NE), may be the first identifiable pathology of AD, and recent data from basic research in animal models of AD indicate that loss of NE incites a neurotoxic proinflammatory condition, reduces A? clearance and negatively impacts cognition - recapitulating key aspects of AD. In addition, evidence linking NE deficiency to neuroinflammation in AD also exists. By promoting proinflammatory responses, suppressing anti-inflammatory responses and impairing A? degradation and clearance, LC degeneration and NE loss can be considered a triple threat to AD pathogenesis. Remarkably, restoration of NE reverses these effects and slows neurodegeneration in animal models, raising the possibility that treatments which increase NE transmission may have the potential to delay or reverse AD-related pathology. This review describes the evidence supporting a key role for noradrenergic-based therapies to slow or prevent progressive neurodegeneration in AD. Specifically, since MCI coincides with the onset of clinical symptoms and brain atrophy, and LC pathology is already present at this early stage of AD pathogenesis, MCI may offer a critical window of time to initiate novel noradrenergic-based therapies aimed at the secondary wave of events that lead to progressive neurodegeneration. Because of the widespread clinical use of drugs with a NE-based mechanism of action, there are immediate opportunities to repurpose existing medications. For example, NE transport inhibitors and NE-precursor therapies that are used for treatment of neurologic and psychiatric disorders have shown promise in animal models of AD, and are now prime candidates for early-phase clinical trials in humans. PMID:23634965

2013-01-01

371

Models of globular proteins in aqueous solutions  

NASA Astrophysics Data System (ADS)

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 a lower critical point under certain conditions.

Wentzel, Nathaniel James

372

Effects of aqueous soil-biochar extracts on representative aquatic organisms: a first evaluation  

NASA Astrophysics Data System (ADS)

Increasing considerations of biochar application to soils has raised concerns over implications to overall environmental quality, associated to some of its components. The heterogeneity of biochar composition is well documented in relation to co-existing chemical species, as a function of feedstock and pyrolysis conditions. Robust ecotoxicology studies with focus on bioavailable biochar components in soil remain scarce and have only started to emerge. This pilot study provides an insight into the potential ecotoxicological effects of aqueous extracts of biochar-amended soil on a range of aquatic organisms (Vibrio fischeri, Pseudokirchneriella subcapitata and Daphnia magna), using a battery of standard aquatic bioassays. The use of such bioassays in environmental risk assessment of soil-biochar elutriates is here suggested as a crucial tool, to bridge the gap between biochar's 'inert' fraction in soil and that bioavailable to edaphic organisms. Aqueous extracts were obtained from LUFA 2.2 standard soil (control) and following amendment with pine biochar at common field application rates (80 ton ha-1). Acute exposure to soil-biochar extracts allowed estimating toxicity parameters and developing dose-response curves for all tested species, through well-established methodological guidelines. The bioluminescent bacteria V. fischeri showed negligible EC50 (effect concentration corresponding to 50% luminescence decline) values in the MICROTOX® basic test (independent of exposure time), suggesting low susceptibility to soil-biochar extracts. Mild toxicity was also observed in the microalgae P. subcapitata growth inhibition test, where significant deleterious effects on growth rate occurred only at the highest (100%) extract concentration (p<0.05). Among the tested species, toxicity was generally more marked in the primary consumer D. magna, with an EC50 (effect concentration corresponding to 50% immobilisation) of 2.95%. The pattern and extent of observed effects were species-specific, thus the use of multiple test species, as part of an integrative ecotoxicological approach, has shown relevance. Preliminary results suggest potential trophic unbalances in aquatic systems, as a result of exposure to leachates from biochar-amended soils.

Bastos, A. C.; Abrantes, N.; Prodana, M.; Verheijen, F.; Keizer, J. J.; Soares, A. M. V. M.; Loureiro, S.

2012-04-01

373

Corrosion problems with aqueous coolants, final report  

SciTech Connect

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.

Diegle, R B; Beavers, J A; Clifford, J E

1980-04-11

374

Study of Corrosion Behavior of Arc Sprayed Aluminum Coating on Mild Steel  

NASA Astrophysics Data System (ADS)

In the current study, aluminum coating was deposited on mild steel by arc spraying. A well-adhered coating with low level of porosity was successfully obtained. To evaluate the corrosion behavior of the coating, electrochemical impedance spectroscopy (EIS) and polarization tests in 3.5% NaCl solution were carried out. The as-coated samples were also subjected to a 1500-h salt spray assay. Polarization tests indicated that the corrosion current density of the aluminum coating is more than that of bulk aluminum. This could be due to the penetration of the electrolyte through open pores, resulted in the acceleration of aluminum corrosion. EIS measurements showed that the corrosion performance of the coating is improved during a long time immersion and exposure to saline mist. This could be due to plugging of pores by corrosion products which hinder further penetration of the electrolyte through the coating. The results obtained indicated that twin wire arc sprayed aluminum coatings can reliably protect steel structures against corrosion in chloride-containing aqueous solutions.

Abedi Esfahani, Erfan; Salimijazi, Hamidreza; Golozar, Mohamad A.; Mostaghimi, Javad; Pershin, Larry

2012-12-01

375

Diagnostic procedures in mild traumatic brain injury: results of the who collaborating centre task force on mild traumatic brain injury  

Microsoft Academic Search

We examined diagnostic procedures in mild traumatic brain injury by a systematic literature search. After screening 38,806 abstracts, we critically reviewed 228 diagnostic studies and accepted 73 (32%). The estimated prevalence of intracranial CT scan abnormalities is 5% in patients presenting to hospital with a Glasgow Coma Scale score of 15 and 30% or higher in patients presenting with a

Jörgen Borg; Lena Holm; J. David Cassidy; Paul M. Peloso; Linda J. Carroll; Hans von Holst; Kaj Ericson

2004-01-01

376

Aqueous Processing Material Accountability Instrumentation  

SciTech Connect

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.

Robert Bean

2007-09-01

377

27 CFR 21.96 - Ammonia, aqueous.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Ammonia, aqueous. 21.96 Section 21...Specifications for Denaturants § 21.96 Ammonia, aqueous. (a) Alkalinity. Strongly alkaline to litmus. (b) Ammonia content. 27 to 30...

2010-04-01

378

27 CFR 21.96 - Ammonia, aqueous.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Ammonia, aqueous. 21.96 Section 21...Specifications for Denaturants § 21.96 Ammonia, aqueous. (a) Alkalinity. Strongly alkaline to litmus. (b) Ammonia content. 27 to 30...

2012-04-01

379

27 CFR 21.96 - Ammonia, aqueous.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Ammonia, aqueous. 21.96 Section 21...Specifications for Denaturants § 21.96 Ammonia, aqueous. (a) Alkalinity. Strongly alkaline to litmus. (b) Ammonia content. 27 to 30...

2013-04-01

380

27 CFR 21.96 - Ammonia, aqueous.  

...2014-04-01 2014-04-01 false Ammonia, aqueous. 21.96 Section 21...Specifications for Denaturants § 21.96 Ammonia, aqueous. (a) Alkalinity. Strongly alkaline to litmus. (b) Ammonia content. 27 to 30...

2014-04-01

381

27 CFR 21.96 - Ammonia, aqueous.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Ammonia, aqueous. 21.96 Section 21...Specifications for Denaturants § 21.96 Ammonia, aqueous. (a) Alkalinity. Strongly alkaline to litmus. (b) Ammonia content. 27 to 30...

2011-04-01

382

A "catch-and-release" protocol for alkyne-tagged molecules based on a resin-bound cobalt complex for peptide enrichment in aqueous media.  

PubMed

The development of new and mild protocols for the specific enrichment of biomolecules is of significant interest from the perspective of chemical biology. A cobalt-phosphine complex immobilised on a solid-phase resin has been found to selectively bind to a propargyl carbamate tag, that is, "catch", under dilute aqueous conditions (pH?7) at 4?°C. Upon acidic treatment of the resulting resin-bound alkyne-cobalt complex, the Nicholas reaction was induced to "release" the alkyne-tagged molecule from the resin as a free amine. Model studies revealed that selective enrichment of the alkyne-tagged molecule could be achieved with high efficiency at 4?°C. The proof-of-concept was applied to an alkyne-tagged amino acid and dipeptide. Studies using an alkyne-tagged dipeptide proved that this protocol is compatible with various amino acids bearing a range of functionalities in the side-chain. In addition, selective enrichment and detection of an amine derived from the "catch and release" of an alkyne-tagged dipeptide in the presence of various peptides has been accomplished under highly dilute conditions, as determined by mass spectrometry. PMID:24788842

Miyazaki, Ayako; Asanuma, Miwako; Dodo, Kosuke; Egami, Hiromichi; Sodeoka, Mikiko

2014-06-23

383

Chemically synthesized glycosides of hydroxylated flavylium ions as suitable models of anthocyanins: binding to iron ions and human serum albumin, antioxidant activity in model gastric conditions.  

PubMed

Polyhydroxylated flavylium ions, such as 3',4',7-trihydroxyflavylium chloride (P1) and its more water-soluble 7-O-?-d-glucopyranoside (P2), are readily accessible by chemical synthesis and suitable models of natural anthocyanins in terms of color and species distribution in aqueous solution. Owing to their catechol B-ring, they rapidly bind FeIII, weakly interact with FeII and promote its autoxidation to FeIII. Both pigments inhibit heme-induced lipid peroxidation in mildly acidic conditions (a model of postprandial oxidative stress in the stomach), the colorless (chalcone) forms being more potent than the colored forms. Finally, P1 and P2 are moderate ligands of human serum albumin (HSA), their likely carrier in the blood circulation, with chalcones having a higher affinity for HSA than the corresponding colored forms. PMID:25514218

Al Bittar, Sheiraz; Mora, Nathalie; Loonis, Michèle; Dangles, Olivier

2014-01-01

384

Mild caloric restriction up-regulates the expression of prohibitin: A proteome study  

SciTech Connect

Research highlights: {yields} Proteomic analysis was performed to elucidate physiological alterations induced by mild CR. {yields} The results suggest good reproducibility and possibility to grasp the important response of CR. {yields} The increase in prohibitin abundance was observed in CR groups by proteomic analysis. {yields} We hypothesize that prohibitin might be involved in the longevity induced by CR. -- Abstract: Caloric restriction (CR) is well known to expand lifespan in a variety of species and to retard many age-related diseases. The effects of relatively mild CR on the proteome profile in relation to lifespan have not yet been reported, despite the more extensive studies of the stricter CR conditions. Thus, the present study was conducted to elucidate the protein profiles in rat livers after mild CR for a relatively short time. Young growing rats were fed CR diets (10% and 30% CR) for 1 month. We performed the differential proteomic analysis of the rat livers using two-dimensional electrophoresis combined with MALDI-TOF mass spectrometry. The most remarkable protein among the differentially expressed proteins was found to be prohibitin, the abundance of which was increased by 30% CR. Prohibitin is a ubiquitously expressed protein shown to suppress cell proliferation and to be related to longevity. The increase in prohibitin was observed both in 10% and 30% CR by Western blot analysis. Furthermore, induction of AMP-activated kinase (AMPK) protein, related to the actions of prohibitin in promoting longevity, was observed. The increased prohibitin level in response to subtle CR suggests that this increase may be one of the early events leading to the expansion of lifespan in response to CR.

Takahashi, Shoko; Masuda, Junko; Shimagami, Hiroshi [Department of Applied Biological Chemistry, The University of Tokyo, Tokyo (Japan)] [Department of Applied Biological Chemistry, The University of Tokyo, Tokyo (Japan); Ohta, Yutaka; Kanda, Tomomasa [Research Laboratories for Health and Gustatory Science, Asahi Breweries Limited, Ibaraki (Japan)] [Research Laboratories for Health and Gustatory Science, Asahi Breweries Limited, Ibaraki (Japan); Saito, Kenji [Department of Applied Biological Chemistry, The University of Tokyo, Tokyo (Japan) [Department of Applied Biological Chemistry, The University of Tokyo, Tokyo (Japan); Corporate Sponsored Research Program 'Food for Life', The University of Tokyo, Tokyo (Japan); Kato, Hisanori, E-mail: akatoq@mail.ecc.u-tokyo.ac.jp [Department of Applied Biological Chemistry, The University of Tokyo, Tokyo (Japan) [Department of Applied Biological Chemistry, The University of Tokyo, Tokyo (Japan); Corporate Sponsored Research Program 'Food for Life', The University of Tokyo, Tokyo (Japan)

2011-02-18

385

Removal and regeneration of aqueous divalent cations by boehmite.  

PubMed

Boehmite (Al(OH)O) was employed for the removal of aqueous Mg(2+), Cu(2+), Cd(2+), Pb(2+), and Co(2+) at 298 K. Although boehmite was able to remove these divalent cations, the greater removal rate with boehmite of Pb(2+) (28.7%) than with Mg(2+), Cu(2+), Cd(2+), and Co(2+) (5.6, 25.3, 10.9, and 13.3%, respectively) was observed under acidic conditions. Under stronger alkaline conditions, in which the lead species was completely dissolved, a greater removal rate of Pb(2+) (more than 80%) was observed under the corresponding conditions employed for the acidic conditions. The removed lead species could not be dissolved from boehmite in an acidic solution while an evident dissolution of lead species was detected using an aqueous NaOH solution. The results shown in the present study reveal that boehmite can be employed as a reagent for the removal and regeneration of aqueous metal cations. PMID:18295777

Sugiyama, Shigeru; Kanda, Yuki; Ishizuka, Hisaaki; Sotowa, Ken-Ichiro

2008-04-15

386

Acute intoxication and illness due to mild analgesics  

PubMed Central

1 Acute intoxication with mild analgesics is relatively uncommon in France. In fact, these drugs have accounted for only about 3.5% of acute drug intoxications seen at the Fernand Widal Hospital, Paris, over the past 10 years. 2 On the other hand, 23% of adverse reactions recorded by a drug monitoring service have been attributed to mild analgesics. 3 It is very difficult to establish the true incidence of acute toxicity and adverse reactions caused by these drugs. They are usually taken without medical supervision; it is often difficult to ascribe toxicity to a single agent when combination products are taken so frequently; and the underlying illness and the use of other drugs must also be considered. 4 The methods currently used to obtain adverse reaction and toxicity data have many disadvantages and shortcomings. PMID:7437278

Fournier, E. P.

1980-01-01

387

Managing Radiation Therapy Side Effects: What to Do about Mild Skin Changes  

MedlinePLUS

... AND HUMAN SERVICES National Institutes of Health Managing Radiation Therapy Side Effects What To Do About Mild Skin ... nurse how to care for these areas. Managing Radiation Therapy Side Effects:What To Do About Mild Skin ...

388

Abundance analysis of barium and mild barium stars  

E-print Network

High signal to noise, high resolution spectra were obtained for a sample of normal, mild barium, and barium giants. Atmospheric parameters were determined from the FeI and FeII lines. Abundances for Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, La, Ce, Nd, Sm, Eu, and Gd, were determined from equivalent widths and model atmospheres in a differential analysis, with the red giant Eps Vir as the standard star. The different levels of s-process overabundances of barium and mild barium stars were earlier suggested to be related to the stellar metallicity. Contrary to this suggestion, we found in this work no evidence of barium and mild barium to having different range in metallicity. However, comparing the ratio of abundances of heavy to light s-process elements, we found some evidence that they do not share the same neutron exposure parameter. The exact mechanism controlling this difference is still not clear. As a by-product of this analysis we identify two normal red giants misclassified as mild barium stars. The relevance of this finding is discussed. Concerning the suggested nucleosynthetic effects possibly related to the s-process, for elements like Cu, Mn, V and Sc, we found no evidence for an anomalous behavior in any of the s-process enriched stars analyzed here. However, further work is still needed since a clear [Cu/Fe] vs. [Ba/H] anticorrelation exists for other s-process enriched objects.

R. Smiljanic; G. F. Porto de Mello; L. da Silva

2007-04-02

389

Metal alkoxide primers in the adhesive bonding of mild steel  

Microsoft Academic Search

The effects of metal alkoxide type and relative humidity on the durability of alkoxide-primed, adhesively bonded steel wedge crack specimens have been determined. Aluminum tri-secbutoxide, aluminum tri-tert-butoxide, tetrabutyl orthosilicate, and titanium(IV ) butoxide were used as alkoxide primers. Grit-blasted, acetone-rinsed mild steel adherends were the substrates bonded with epoxy and polyethersulfone. The two aluminum alkoxides significantly enhanced the durability of

Beena Menon; R. A. Pike; J. P. Wightman

1991-01-01

390

Specific cognitive deficits in mild frontal variant frontotemporal dementia  

Microsoft Academic Search

Summary Eight patients with relatively mild frontal variant frontotemporal dementia (fvFTD) were compared with age- and IQ-matched control volunteers on tests of executive and mnemonic function. Tests of pattern and spatial recognition memory, spatial span, spatial working memory, planning, visual discrimination learning\\/ attentional set-shifting and decision-making were employed. Patients with fvFTD were found to have deficits in the visual discrimination

Shibley Rahman; Barbara J. Sahakian; John R. Hodges; Robert D. Rogers; Trevor W. Robbins

1999-01-01

391

Differential Hypometabolism Patterns according to Mild Cognitive Impairment Subtypes  

Microsoft Academic Search

Aims: The present study investigated cerebral glucose metabolism and structural atrophy in controls and subjects with mild cognitive impairment (MCI). Methods: The study included 13 controls, 7 MCI subjects considered as prodromal Alzheimer’s disease (MCI of the Alzheimer type, aMCI) and 7 MCI subjects having cognitive decline due to other causes, established by clinical evaluation (MCI of the non-Alzheimer type,

Anne M. Jauhiainen; Tuija Kangasmaa; Minna Rusanen; Eini Niskanen; Susanna Tervo; Miia Kivipelto; Ritva L. Vanninen; Jyrki T. Kuikka; Hilkka Soininen

2008-01-01

392

Reaction zones and their structure in MILD combustion  

E-print Network

Reaction zones and their structure in MILD combustion Y. Minamoto, N. Swaminathan?, R. S. Cant, T. Leung Department of Engineering, Cambridge University, Cambridge, CB2 1PZ, UK. ?Corresponding author: Department of Engineering, Cambridge University... high combustion efficiency with low levels of both chemical and noise pollu- tion (Wu¨nning & Wu¨nning, 1997; Katsuki & Hasegawa, 1998; Cavaliere & de Joannon, 2004). This technology is used mainly in furnaces predominantly employing internal...

Minamoto, Y.; Swaminathan, N.; Cant, R. S.; Leung, T.

2014-06-26

393

Vascular Risk Factors in Mild Cognitive Impairment Subtypes  

Microsoft Academic Search

Background and Aim: To investigate the role of vascular risk factors in different subtypes of mild cognitive impairment (MCI) in a multicentric, clinic-based, cross-sectional study. Methods: Two-hundred and seven subjects with MCI were included in the study: 33 with single non-memory MCI (snmMCI), 42 with multiple-domain amnestic MCI (mdMCI-a) and 132 with amnestic MCI (aMCI). Several clinical vascular risk factors

E. Mariani; R. Monastero; S. Ercolani; F. Mangialasche; M. Caputo; F. T. Feliziani; D. F. Vitale; U. Senin; P. Mecocci

2007-01-01

394

The diagnostic value of electroencephalography in mild senile Alzheimer's disease  

Microsoft Academic Search

Objective: We investigated the diagnostic value of the visually assessed electroencephalogram (EEG) in patients with mild Alzheimer's disease (AD), using the grand total of EEG (GTE) score.Methods: Forty-nine non-demented control subjects with and without minimal cognitive impairment from the general population and 86 probable AD patients (NINCDS-ADRDA criteria), consecutively referred to a memory clinic, participated in this study.Results: Frequency of

J. J. Claus; R. L. M. Strijers; E. J. Jonkman; B. W. Ongerboer De Visser; C. Jonker; G. J. M. Walstra; P. H. Scheltens; W. A van Gool

1999-01-01

395

Reflective training and causal attributions in impulsive mildly retarded children  

Microsoft Academic Search

Modification of an impulsive conceptual tempo in a population of 30 mildly retarded young (MA=8.17) and older (MA=10.13) children was examined. An operant treatment, involving contingent social reinforcement, was not effective in reducing impulsive responding on the MFFT. Limited and extended self?instructional training did produce a posttrain?ing increase in reflective responding which was maintained two weeks after training ceased. Age?related

Clarissa S. Holmes

1981-01-01

396

Sustained mild hypergravity reduces spontaneous cardiac baroreflex sensitivity.  

PubMed

Head-to-foot gravitational force >1G (+Gz hypergravity) augments venous pooling in the lower body and reduces central blood volume during exposure, compared with 1Gz. Central hypovolemia has been reported to reduce spontaneous cardiac baroreflex sensitivity. However, no investigations have examined spontaneous cardiac baroreflex sensitivity during exposure to sustained mild +Gz hypergravity. We therefore hypothesized that mild +Gz hypergravity would reduce spontaneous cardiac baroreflex sensitivity, compared with 1Gz. To test this hypothesis, we examined spontaneous cardiac baroreflex sensitivity in 16 healthy men during exposure to mild +Gz hypergravity using a short-arm centrifuge. Beat-to-beat arterial blood pressure (tonometry) and R-R interval (electrocardiography) were obtained during 1Gz and 1.5Gz exposures. Spontaneous cardiac baroreflex sensitivity was assessed by sequence slope and transfer function gain. Stroke volume was calculated from the arterial pressure waveform using a three-element model. All indices of spontaneous cardiac baroreflex sensitivity decreased significantly (up slope: 18.6±2.3?12.7±1.6ms/mmHg, P<0.001; down slope: 19.0±2.5?13.2±1.3ms/mmHg, P=0.002; transfer function gain in low frequency: 14.4±2.2?10.1±1.1ms/mmHg, P=0.004; transfer function gain in high frequency: 22.2±7.5?12.4±3.5ms/mmHg, P<0.001). Stroke volume decreased significantly (88±5?80±6ml, P=0.025). Moreover, although systolic arterial pressure variability increased, R-R interval variability did not increase. These results suggest that even mild +Gz hypergravity reduces spontaneous cardiac baroreflex sensitivity, increasing the risk of cardiovascular disturbance during the exposure. PMID:25156804

Yanagida, Ryo; Ogawa, Yojiro; Ueda, Kaname; Aoki, Ken; Iwasaki, Ken-ichi

2014-10-01

397

A new synthesis of TATB using inexpensive starting materials and mild reaction conditions  

SciTech Connect

TATB is currently manufactured in US by nitration of the expensive TCB to give 2,4,6-trichloro-1,3,5-trinitrobenzene which is then aminated to yield TATB. Elevated temperatures (150 C) are required for both reactions. There is a need for a more economical synthesis of TATB that also addresses current environmental issues. We have recently found that 1,1,1-trimethylhydrazinium iodide (TMHI) allows the amination of nitroarenes at ambient temperature via Vicarious Nucleophilic Substitution of hydrogen. TMHI reacts with picramide in presence of strong base (NaOMe or t-BuOK) to give TATB in over 95% yield. TMHI and picramide can be obtained from either inexpensive starting materials or surplus energetic materials from demilitarization activities, such as the 30,000 metric tons of UDMH (surplus rocket propellant) from the former Soviet Union.

Mitchell, A.R.; Pagoria, P.F.; Schmidt, R.D.

1996-04-01

398

Sonocatalyzed facile and mild one pot synthesis of gem-dichloroaziridine derivatives under alkaline conditions.  

PubMed

In this research, rapid and efficient preparation of 2,2-dichloro-1,3-diarylaziridines through the reaction of Schiff base compounds with dichlorocarbene yielded in situ from chloroform and sodium hydroxide without any phase transfer catalyst under ultrasonic irradiation is described. The advantages of this reaction are very short reaction times, excellent product yields, simplicity of the method and high purity of products. PMID:21775185

Naeimi, Hossein; Rabiei, Khadijeh

2012-01-01

399

Controlled synthesis of porous coordination-polymer microcrystals with definite morphologies and sizes under mild conditions.  

PubMed

Herein, we report a facile and convenient method for the synthesis of the porous coordination polymer MOF-14 [Cu3 (BTB)2 ] (H3 BTB=4,4',4''-benzene-1,3,5-triyl-tribenzoic acid) as microcrystals with definite shapes and crystal facets controlled by the reaction medium at room temperature. The amount of sodium acetate added to the reaction system plays a crucial role in the shape evolution of MOF-14 from rhombic dodecahedrons to truncated rhombic dodecahedrons and cubes with truncated edges and then to cubes. The addition of a base could accelerate the formation rate of crystal growth and increase the supersaturation of crystal growth, thus resulting in the formation of MOF-14 cube crystals with high-energy crystal facets. The morphological evolution was also observed for HKUST-1 [Cu3 (BTC)2 ] (H3 BTC=1,3,5-benzenetricarbocylic acid) from octahedrons to cubes, thus verifying the probable mechanism of the morphological transformation. The gas-adsorption properties of MOF-14 with different shapes were studied and reveal that the porous coordination-polymer microcrystals display excellent and morphology-dependent sorption properties. PMID:25224902

Liu, Qing; Yang, Ji-Min; Jin, Li-Na; Sun, Wei-Yin

2014-11-01

400

Rhodium-Catalyzed Ketone Methylation Using Methanol Under Mild Conditions: Formation of ?-Branched Products**  

PubMed Central

The rhodium-catalyzed methylation of ketones has been accomplished using methanol as the methylating agent and the hydrogen-borrowing method. The sequence is notable for the relatively low temperatures that are required and for the ability of the reaction system to form ?-branched products with ease. Doubly alkylated ketones can be prepared from methyl ketones and two different alcohols by using a sequential one-pot iridium- and rhodium-catalyzed process. PMID:24288297

Chan, Louis K M; Poole, Darren L; Shen, Di; Healy, Mark P; Donohoe, Timothy J

2014-01-01

401

One-step degradation of cellulose to 5-hydroxymethylfurfural in ionic liquid under mild conditions.  

PubMed

One-step conversion of cellulose to HMF (5-hydroxymethylfurfural) has been achieved by using metal chlorides (CrCl3, CuCl2, SnCl4, WCl6) in [BMIM]Cl. The effects of temperature, reaction time, amount of catalysts, and the purity of [BMIM]Cl on the performance have been studied and discussed in detail. More than 63% yield of HMF and 80% yield of TRS (total reducing sugar) were obtained in [BMIM]Cl with CrCl3 at 120°C under atmospheric pressure. Filter paper and cotton were also used as a source for cellulose degradation to HMF, but only a moderate yield of HMF was obtained (40% for filter paper and 12% for cotton). The reutilization of this system was examined and the reaction mechanism was also discussed. PMID:25498690

Zhou, Lilong; He, Yiming; Ma, Zhanwei; Liang, Runjuan; Wu, Tinghua; Wu, Ying

2015-03-01

402

Shape-controlled synthesis of wurtzite ZnS microstructures under mild solvothermal condition.  

PubMed

Through a facile solvothermal route using zinc chloride and thiourea as reactants, wurtzite ZnS and its precursor ZnS . (en)0.5 (en = ethylenediamine) with various morphologies and sizes were grown, which were characterized by XRD, SEM, TEM and N2 adsorption and so on. The phase evolution, composition and morphologies of the products are highly dependent on the concentration of en. By keeping the en-water volume ratio at 1/2 to 1, the nanostripes-flower or nanorod-spheric wurtzite ZnS were easily obtained under 120 degrees C for 6-24 h, which possess relatively higher specific surface area and larger total pore volume. PMID:19441422

Duan, L M; Quan, Z W; Yang, P P; Wang, H; Lin, J

2009-02-01

403

Untreated mild traumatic brain injury in a young adult population.  

PubMed

The current study was conducted to determine (a) the demographic and injury characteristics of individuals who did not receive treatment for mild brain injury and (b) the reasons these individuals do not receive or seek treatment. In a large sample of undergraduate students initially surveyed via an on-line questionnaire (n = 1,853), 35% of those who responded to a subsequent survey acknowledged that they had experienced at least one mild traumatic brain injury (TBI) for which they were not treated. Compared with those who were treated for each TBI, those who were untreated were more likely to be men and were less likely to report persisting symptoms 3 months after the injury. There were no differences in demographics or injury characteristics (e.g., length of time unconscious) between groups. Of those with an untreated TBI, the most common reasons for not seeking treatment were that the symptoms resolved quickly and that they were neither bothersome nor disruptive. Findings are discussed in terms of research on recovery from mild TBI. PMID:20197295

Demakis, George J; Rimland, Casey A

2010-05-01

404

Sedimentary basin inversion: mild reactivation to intraplate orogenesis  

NASA Astrophysics Data System (ADS)

"Basin inversion" describes the shortening and - at least partial - uplift and erosion of sedimentary basins initially formed as extensional basins, typically as rift basins. It represents an important mode of tectonic deformation of continental lithosphere away from active plate margins where most of the causative driving forces are generated. A key expression of basin inversion often preserved by the intraplate sedimentary record is the reactivation ("inversion") of initially normal, rift-related, basement and intra-sedimentary faults as reverse faults during the shortening phase. Even where these deformations are shallow and mild it is generally understood that deeper, lithosphere-scale, processes are involved that link them with stresses generated at plate boundaries. This implies that such intraplate deformation may progress beyond mild fault reactivations and inversion-related folding to structural styles at a crustal or lithosphere scale and, with sufficient shortening, mimicking those formed at collisional orogens. This postulated continuum of intraplate deformation of sedimentary basins, from mild basin inversion to intraplate orogenesis, is investigated in this presentation by considering a number of geological examples from the literature and the author's own experience. It is concluded that many large-scale compressional features within long-lived zones of convergence, usually interpreted to be indicative of plate boundary formation and formal subduction of short-lived but, nevertheless, implicitly mature ocean basins, are in fact the expressions of large-scale "mega" sedimentary basin inversion occurring in an intraplate setting.

Stephenson, Randell

2014-05-01

405

Overlapping MERS and mild AESD caused by HHV-6 infection.  

PubMed

We report the case of an overlapping encephalopathy syndrome consisting of clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) and a mild form of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) caused by human herpesvirus-6. A previously healthy 17-month-old girl was admitted to our hospital as a precaution because of seizures that had developed more than 25hours (h) after fever. Brain diffusion-weighted images (DWI) showed high signal intensity in the central splenial region on Day 2. She regained consciousness 16h after the second seizure. On Day 6, she had a secondary cluster of partial seizures. DWI showed resolution of the splenial lesion and revealed reduced diffusion in the fronto-subcortical white matter. She regained consciousness 36h after the secondary cluster of seizures without any sequelae. A third DWI performed on Day 15 showed that the fronto-subcortical white matter lesions had completely disappeared. Based on the clinicoradiological findings, we diagnosed the patient with overlapping MERS and mild AESD. Our case, together with previous reports, suggests that patients can develop combined encephalopathy syndromes as a phenotype. Many encephalopathy syndromes have been established and classified; however, some may not present as independent syndromes. PMID:24856142

Hatanaka, Mari; Kashiwagi, Mitsuru; Tanabe, Takuya; Nakahara, Hiroshi; Ohta, Kazumi; Tamai, Hiroshi

2015-03-01

406

Hormetic Modulation of Aging and Longevity by Mild Heat Stress  

PubMed Central

Aging is characterized by a stochastic accumulation of molecular damage, progressive failure of maintenance and repair, and consequent onset of age-related diseases. Applying hormesis in aging research and therapy is based on the principle of stimulation of maintenance and repair pathways by repeated exposure to mild stress. In a series of experimental studies we have shown that repetitive mild heat stress has anti-aging hormetic effects on growth and various other cellular and biochemical characteristics of human skin fibroblasts undergoing aging in vitro. These effects include the maintenance of stress protein profiles, reduction in the accumulation of oxidatively and glycoxidatively damaged proteins, stimulation of the proteasomal activities for the degradation of abnormal proteins, improved cellular resistance to ethanol, hydrogenperoxide and ultraviolet-B rays, and enhanced levels of various antioxidant enzymes. Anti-aging hormetic effects of mild heat shock appear to be facilitated by reducing protein damage and protein aggregation by activating internal antioxidant, repair and degradation processes. PMID:18648625

Rattan, Suresh I. S.

2005-01-01

407

Automatic morphometry in Alzheimer's disease and mild cognitive impairment???  

PubMed Central

This paper presents a novel, publicly available repository of anatomically segmented brain images of healthy subjects as well as patients with mild cognitive impairment and Alzheimer's disease. The underlying magnetic resonance images have been obtained from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. T1-weighted screening and baseline images (1.5 T and 3 T) have been processed with the multi-atlas based MAPER procedure, resulting in labels for 83 regions covering the whole brain in 816 subjects. Selected segmentations were subjected to visual assessment. The segmentations are self-consistent, as evidenced by strong agreement between segmentations of paired images acquired at different field strengths (Jaccard coefficient: 0.802 ± 0.0146). Morphometric comparisons between diagnostic groups (normal; stable mild cognitive impairment; mild cognitive impairment with progression to Alzheimer's disease; Alzheimer's disease) showed highly significant group differences for individual regions, the majority of which were located in the temporal lobe. Additionally, significant effects were seen in the parietal lobe. Increased left/right asymmetry was found in posterior cortical regions. An automatically derived white-matter hypointensities index was found to be a suitable means of quantifying white-matter disease. This repository of segmentations is a potentially valuable resource to researchers working with ADNI data. PMID:21397703

Heckemann, Rolf A.; Keihaninejad, Shiva; Aljabar, Paul; Gray, Katherine R.; Nielsen, Casper; Rueckert, Daniel; Hajnal, Joseph V.; Hammers, Alexander

2011-01-01

408

Caregivers' quality of life in mild and moderate dementia.  

PubMed

Objective To investigate quality of life (QoL) of caregivers of mild and moderate dementia and the aspects related to QoL. Method Cross-sectional assessment of dyads of people with dementia (PwD) and family caregivers (n=88). Results Burden (p<0.05) and depressive symptoms (p<0.001) were related to caregivers' QoL in both stages of dementia. In mild dementia, caregivers' depressive symptoms (p<0.001) and PwD neuropsychiatric symptoms (p<0.001) were related to burden. PwD aberrant motor activity (p<0.001) and anxiety (p<0.001), and caregiver-reported QoL domains of friends (p<0.001) and mood (p<0.05) were related to depressive symptoms. In moderate dementia, self-reported QoL (p<0.01) and anxiety (p<0.01), and PwD anxiety (p<0.01) were related to burden. Caregivers' anxiety (p<0.001) and self-reported QoL (p<0.001) were related to depressive symptoms. Conclusion Burden and depressive symptoms were related to QoL of caregivers of mild and moderate dementia. However, they are driven by different factors according to dementia severity. PMID:25517642

Santos, Raquel Luiza; Sousa, Maria Fernanda Barroso de; Simões-Neto, José Pedro; Nogueira, Marcela Lima; Belfort, Tatiana T; Torres, Bianca; Rosa, Rachel Dias Lopes da; Laks, Jerson; Dourado, Marcia Cristina Nascimento

2014-12-01

409

Cerebrovascular regulation, exercise, and mild traumatic brain injury.  

PubMed

A substantial number of people who sustain a mild traumatic brain injury report persistent symptoms. Most common among these symptoms are headache, dizziness, and cognitive difficulties. One possible contributor to sustained symptoms may be compromised cerebrovascular regulation. In addition to injury-related cerebrovascular dysfunction, it is possible that prolonged rest after mild traumatic brain injury leads to deconditioning that may induce physiologic changes in cerebral blood flow control that contributes to persistent symptoms in some people. There is some evidence that exercise training may reduce symptoms perhaps because it engages an array of cerebrovascular regulatory mechanisms. Unfortunately, there is very little work on the degree of impairment in cerebrovascular control that may exist in patients with mild traumatic brain injury, and there are no published studies on the subacute phase of recovery from this injury. This review aims to integrate the current knowledge of cerebrovascular mechanisms that might underlie persistent symptoms and seeks to synthesize these data in the context of exploring aerobic exercise as a feasible intervention to treat the underlying pathophysiology. PMID:25274845

Tan, Can Ozan; Meehan, William P; Iverson, Grant L; Taylor, J Andrew

2014-10-28

410

[Extraction of rifamycin B from native and aqueous solutions].  

PubMed

Optimal conditions for extraction of rifamycin B from aqueous solutions and fermentation broth filtrates at pH values within 2.0-7.0 were determined. When the antibiotic was extracted from the aqueous solutions, the highest yield was obtained at pH 2.0. When the antibiotic was extracted from the fermentation broth filtrates, it was found that chloroform was the most selective solvent with respect to rifamycin B, the chloroform selectivity being increased at pH 3.5-4.0. It was shown that rifamicin B passed from the buffer solutions with a concentration of 3-20 mg/ml to chloroform in amounts of 6-7 mg/ml and to ethylacetate and butanol in amounts of 20 mg/ml. Such conditions of chloroform and butanol (9 : 1) increased the rifamycin B contents in the extract up to 40 mg/ml. PMID:237467

Tolstykh, I V; Konstantinova, N V; Grishin, I A; Pokras, L S

1975-03-01

411

Aqueous Humor Rapidly Stimulates Myocilin Secretion from Human Trabecular Meshwork Cells  

PubMed Central

Myocilin, a protein associated with the development of glaucoma, is expressed in most eye tissues with highest expression observed in trabecular meshwork cells. In culture, primary human trabecular meshwork cells incubated in 10% fetal bovine serum have reduced myocilin expression compared to in vivo, but incubation in human aqueous humor, their normal in vivo nutrient source, restores myocilin expression to near in vivo levels. To investigate the mechanism by which human aqueous humor stimulates myocilin accumulation in conditioned media from normal human trabecular meshwork cells, three independent trabecular meshwork cell lines were cultured in Dulbecco’s Modified Eagle’s Medium (DMEM) containing various supplements: fetal bovine serum (10%), human serum (0.2%), porcine aqueous humor (50%), bovine serum albumin (0.1%), dexamethasone (10?7 M), human aqueous humor (50%) or heat-inactivated human aqueous humor (50%). Conditioned media from cultured primary trabecular meshwork cells following incubation in human aqueous humor showed significant accumulation of myocilin in a time- (15 minutes) and dose-dependent manner (half maximal effective concentration ~ 30%) while intracellular myocilin levels decreased. Minimal myocilin accumulation was observed in conditioned media isolated from trabecular meshwork cells cultured in DMEM containing fetal bovine or human serum, bovine serum albumin, porcine aqueous humor, dexamethasone or DMEM alone. Heat inactivation of human aqueous humor nearly eliminated human aqueous humor-stimulated myocilin secretion. Inhibitors of new protein synthesis, gene transcription, the endoplasmic reticulum/Golgi system and endocytic/exocytic secretory pathways failed to inhibit human aqueous humor-stimulated myocilin secretion. Using immunolabeling and transmission electron microscopy, myocilin was found associated with 70–90 nm vesicle-like structures within the cytoplasm of human aqueous humor treated trabecular meshwork cells. These studies suggest that myocilin secretion from trabecular meshwork cells occurs in a Golgi-independent manner following human aqueous humor treatment. Heat-labile factors in human aqueous humor are responsible for the time- and dose-dependent release of myocilin from vesicle-like structures within the cytoplasm of trabecular meshwork cells. PMID:20932969

Resch, Zachary T.; Hann, Cheryl R.; Cook, Kimberly A.; Fautsch, Michael P.

2010-01-01

412

Mild ArI-catalyzed C(sp²)-H or C(sp³)-H functionalization/C-O formation: an intriguing catalyst-controlled selectivity switch.  

PubMed

A tandem C(sp(2))-H and C(sp(3))-H functionalization/C-O bond formation catalyzed by iodine(III) reagents generated in situ has been developed. The method shows wide scope under mild conditions and exhibits an unprecedented selectivity profile that can be switched depending on the catalyst employed. PMID:25156610

Wang, Xueqiang; Gallardo-Donaire, Joan; Martin, Ruben

2014-10-01

413

Standard potentials in aqueous solution  

Microsoft Academic Search

Each of the 24 chapters of this book on standard electrode potentials in aqueous solutions was prepared by knowledgeable specialized experts and reviewed by referees who are credited herein. For the sake of space, discretion was exercised as to which half-reactions would be included for a given element, data have been limited to a single temperature, 25°C, and no attempt

A. J. Bard; R. Parsons; J. Jordan

1985-01-01

414

Protein Hydration in Aqueous Solution  

Microsoft Academic Search

High-resolution proton nuclear magnetic resonance studies of protein hydration in aqueous solution show that there are two qualitatively different types of hydration sites. A well-defined, small number of water molecules in the interior of the protein are in identical locations in the crystal structure and in solution, and their residence times are in the range from about 10-2 to 10-8

Gottfried Otting; Edvards Liepinsh; Kurt Wuthrich

1991-01-01

415

Aqueous acetone extraction of cottonseed  

Microsoft Academic Search

Extraction of cottonseed flakes with acetone containing 25-30% water removes essentially all of the gossypol, most of the\\u000a free fatty acids, about half the raffinose, and negligible quanti-ties of neutral oil and protein. After drying and re-flaking\\u000a of the aqueous acetone extracted marc, the oil may be removed either by hexane extrac-tion or pressing to produce light-colored\\u000a meals exceptionally low

Walter A. Pons; Paul H. Eaves

1967-01-01

416

The Melting of Aqueous Foams  

NASA Technical Reports Server (NTRS)

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.

Durian, Douglas J.; Gopal, Anthony D.; Vera, Moin U.; Langer, Stephen A.

1996-01-01

417

fMRI studies of associative encoding in young and elderly controls and mild Alzheimer's disease  

E-print Network

PAPER fMRI studies of associative encoding in young and elderly controls and mild Alzheimer activation seen in normal aging and in mild Alzheimer's disease by functional magnetic resonance imaging (f with mild Alzheimer's disease were studied using fMRI during a face­name association encoding task. The f

Schacter, Daniel

418

Quantitative Electroencephalography Power and Coherence in Alzheimer's Disease and Mild Cognitive Impairment  

Microsoft Academic Search

In this study the best combination of quantitative electroencephalographic variables (qEEG) for the discrimination of groups with mild to moderate Alzheimer's disease (AD), mild cognitive impairment and healthy subjects was defined and related to neuropsychological performance. The study population included 18 patients with mild to moderate probable AD, 19 subjects with objective memory disturbances, 17 subjects with subjective memory complaints

Vesna Jelic; Masahiro Shigeta; Per Julin; Ove Almkvist; Bengt Winblad; Lars-Olof Wahlund

1996-01-01

419

Low-heat, mild alkaline pretreatment of switchgrass for anaerobic digestion.  

PubMed

This study examines the effectiveness of alkaline pretreatment under mild heat conditions (100°C or 212°F) on the anaerobic co-digestion of switchgrass. The effects of alkaline concentration, types of alkaline, heating time and rinsing were evaluated. In addition to batch studies, continuous-feed studies were performed in triplicate to identify potential digester operational problems caused by switchgrass co-digestion while accounting for uncertainty due to digester variability. Few studies have examined anaerobic digestion of switchgrass or the effects of mild heating to enhance alkaline pretreatment prior to biomass digestion. Results indicate that pretreatment can significantly enhance digestion of coarse-ground (? 0.78 cm particle size) switchgrass. Energy conversion efficiency as high as 63% was observed, and was comparable or superior to fine-grinding as a pretreatment method. The optimal NaOH concentration was found to be 5.5% (wt/wt alkaline/biomass) with a 91.7% moisture level. No evidence of operational problems such as solids build-up, poor mixing, or floating materials were observed. These results suggest the use of waste heat from a generator could reduce the concentration of alkaline required to adequately pretreat lignocellulosic feedstock prior to anaerobic digestion. PMID:24410687

Jin, Guang; Bierma, Tom; Walker, Paul M

2014-01-01

420

Mild Anastomotic Stenosis in Patient-Specific CABG Model May Enhance Graft Patency: A New Hypothesis  

PubMed Central

It is well known that flow patterns at the anastomosis of coronary artery bypass graft (CABG) are complex and may affect the long-term patency. Various attempts at optimal designs of anastomosis have not improved long-term patency. Here, we hypothesize that mild anastomotic stenosis (area stenosis of about 40–60%) may be adaptive to enhance the hemodynamic conditions, which may contribute to slower progression of atherosclerosis. We further hypothesize that proximal/distal sites to the stenosis have converse changes that may be a risk factor for the diffuse expansion of atherosclerosis from the site of stenosis. Twelve (12) patient-specific models with various stenotic degrees were extracted from computed tomography images using a validated segmentation software package. A 3-D finite element model was used to compute flow patterns including wall shear stress (WSS) and its spatial and temporal gradients (WSS gradient, WSSG, and oscillatory shear index, OSI). The flow simulations showed that mild anastomotic stenosis significantly increased WSS (>15 dynes?cm?2) and decreased OSI (<0.02) to result in a more uniform distribution of hemodynamic parameters inside anastomosis albeit proximal/distal sites to the stenosis have a decrease of WSS (<4 dynes?cm?2). These findings have significant implications for graft adaptation and long-term patency. PMID:24058488

Huo, Yunlong; Luo, Tong; Guccione, Julius M.; Teague, Shawn D.; Tan, Wenchang; Navia, José A.; Kassab, Ghassan S.

2013-01-01

421

Neural correlates of saccadic inhibition in healthy elderly and patients with amnestic mild cognitive impairment  

PubMed Central

Performance on tasks that require saccadic inhibition declines with age and altered inhibitory functioning has also been reported in patients with Alzheimer's disease. Although mild cognitive impairment (MCI) is assumed to be a high-risk factor for conversion to AD, little is known about changes in saccadic inhibition and its neural correlates in this condition. Our study determined whether the neural activation associated with saccadic inhibition is altered in persons with amnestic mild cognitive impairment (aMCI). Functional magnetic resonance imaging (fMRI) revealed decreased activation in parietal lobe in healthy elderly persons compared to young persons and decreased activation in frontal eye fields in aMCI patients compared to healthy elderly persons during the execution of anti-saccades. These results illustrate that the decline in inhibitory functions is associated with impaired frontal activation in aMCI. This alteration in function might reflect early manifestations of AD and provide new insights in the neural activation changes that occur in pathological ageing. PMID:23898312

Alichniewicz, K. K.; Brunner, F.; Klünemann, H. H.; Greenlee, M. W.

2013-01-01

422

If Cooperation Is Likely Punish Mildly: Insights from Economic Experiments Based on the Snowdrift Game  

PubMed Central

Punishment may deter antisocial behavior. Yet to punish is costly, and the costs often do not offset the gains that are due to elevated levels of cooperation. However, the effectiveness of punishment depends not only on how costly it is, but also on the circumstances defining the social dilemma. Using the snowdrift game as the basis, we have conducted a series of economic experiments to determine whether severe punishment is more effective than mild punishment. We have observed that severe punishment is not necessarily more effective, even if the cost of punishment is identical in both cases. The benefits of severe punishment become evident only under extremely adverse conditions, when to cooperate is highly improbable in the absence of sanctions. If cooperation is likely, mild punishment is not less effective and leads to higher average payoffs, and is thus the much preferred alternative. Presented results suggest that the positive effects of punishment stem not only from imposed fines, but may also have a psychological background. Small fines can do wonders in motivating us to chose cooperation over defection, but without the paralyzing effect that may be brought about by large fines. The later should be utilized only when absolutely necessary. PMID:23741367

Jiang, Luo-Luo; Perc, Matjaž; Szolnoki, Attila

2013-01-01

423

31P NMR Kinetics Study of Cardiac Metabolism under Mild Hypoxia  

NASA Astrophysics Data System (ADS)

The effects of mild hypoxia on the metabolic and mechanical functions of isovolumic perfused rat hearts have been studied. 31P NMR has been used to follow the metabolite concentrations as well as the intracellular pH. Additionally, the energy transfer through the creatine kinase reaction was estimated by the magnetization-transfer technique. The needs of myofibrillar energy and of mitochondrial ATP production have been assessed through mechanical activity and oxygen-consumption rate. It has been observed that mild hypoxia simultaneously impairs contractile and metabolic functions. The aerobic ATP production is maintained under these conditions while anaerobic energy metabolism seems accelerated. The accumulation of some metabolites (ADP and P i) and the decrease of creatine kinase forward flux ( Vfor) tend, however, to prove that ATP availability for myofibrils is lowered. The large aerobic energy production observed must therefore be explained by an energy wastage in the mitochondria. In spite of normal ATP concentration, a contractile dysfunction is observed and can be explained by the P i accumulation, which is known to impair the use of the myofibrillar ATP. Another hypothesis supported by the magnetization transfer experiments is the poor ATP availability resulting from the ATP wastage in the mitochondria and from the inefficient energy transport by the PCr-Cr shuttle.

Goudemant, J. F.; Elst, L. V.; Vanhaverbeke, Y.; Muller, R. N.

424

Deletion of TRIM32 protects mice from anxiety- and depression-like behaviors under mild stress.  

PubMed

Chronic stress causes a variety of psychiatric disorders such as anxiety and depression, but its mechanism is not well understood. Tripartite motif-containing protein 32 (TRIM32) was strongly associated with autism spectrum disorder, attention deficit hyperactivity disorder, anxiety and obsessive compulsive disorder based on a study of copy number variation, and deletion of TRIM32 increased neural proliferation and reduced apoptosis. Here, we propose that TRIM32 is involved in chronic stress-induced affective behaviors. Using a chronic unpredictable mild stress mouse depression model, we studied expression of TRIM32 in brain tissue samples and observed behavioral changes in Trim32 knockout mice. The results showed that TRIM32 protein but not its mRNA was significantly reduced in hippocampus in a time-dependent manner within 8 weeks of chronic stress. These stress-induced affective behaviors and reduction of TRIM32 protein expression were significantly reversed by antidepressant fluoxetine treatment. In addition, Trim32 knockout mice showed reduced anxiety and depressive behaviors and hyperactivities compared with Trim32 wild-type mice under normal and mild stress conditions. We conclude that TRIM32 plays important roles in regulation of hyperactivities and positively regulates the development of anxiety and depression disorders induced by chronic stress. PMID:24839933

Ruan, Chun-Sheng; Wang, Shu-Fen; Shen, Yan-Jun; Guo, Yi; Yang, Chun-Rui; Zhou, Fiona H; Tan, Li-Tao; Zhou, Li; Liu, Jian-Jun; Wang, Wen-Yue; Xiao, Zhi-Cheng; Zhou, Xin-Fu

2014-08-01

425

If cooperation is likely punish mildly: insights from economic experiments based on the snowdrift game.  

PubMed

Punishment may deter antisocial behavior. Yet to punish is costly, and the costs often do not offset the gains that are due to elevated levels of cooperation. However, the effectiveness of punishment depends not only on how costly it is, but also on the circumstances defining the social dilemma. Using the snowdrift game as the basis, we have conducted a series of economic experiments to determine whether severe punishment is more effective than mild punishment. We have observed that severe punishment is not necessarily more effective, even if the cost of punishment is identical in both cases. The benefits of severe punishment become evident only under extremely adverse conditions, when to cooperate is highly improbable in the absence of sanctions. If cooperation is likely, mild punishment is not less effective and leads to higher average payoffs, and is thus the much preferred alternative. Presented results suggest that the positive effects of punishment stem not only from imposed fines, but may also have a psychological background. Small fines can do wonders in motivating us to chose cooperation over defection, but without the paralyzing effect that may be brought about by large fines. The later should be utilized only when absolutely necessary. PMID:23741367

Jiang, Luo-Luo; Perc, Matjaž; Szolnoki, Attila

2013-01-01

426

The role of hepcidin in chronic mild stress-induced depression.  

PubMed

Depression is one of the most prevalent challenges of mental conditions. Yet its exact etiology has not been clear. Chronic stress increases the production of cytokines, which can lead to depression. Hepcidin, an iron modulator, is involved in the inflammation process as well as iron homeostasis. This study was designed to investigate the role of hepcidin, on stress-induced depression. 60 male wistar rats were entered the experiment. We used a chronic unpredictable mild stress (for 28 days) as a rat model of depression. In stressed group, three subgroups were treated with three different doses of dalteparin (a hepcidin inhibitor): 70IU/kg, 100IU/kg and 140IU/kg daily, for 4 weeks. The animals in the stressed group had more depressive-like behavior than the control group. Moreover, chronic mild stress produced an increased serum interleukin-6 levels. These effects were accompanied by an obvious increase in hepcidin mRNA level and iron content in the hippocampus. These changes were blocked by the injection of dalteparin. In conclusion, inhibition of hepcidin may reduce many pathological changes seen in stress-induced depressive disorders. PMID:25576700

Farajdokht, Fereshteh; Soleimani, Mansoureh; Mehrpouya, Sara; Barati, Mahmood; Nahavandi, Arezo

2015-02-19

427

Chromate removal from aqueous wastes by reduction with ferrous ion  

Microsoft Academic Search

Experimental measurements of reaction stoichiometries indicate that optimum conditions for chromate removal from oxygenated, 25°C aqueous wastes by reduction with ferrous ion occur at pH less than 10.0 in solutions containing the following anions: ClOâ⁻, Cl⁻, F⁻, NOâ⁻, and POâ\\/sup 3 -\\/. At pH greater than 10.0 and at lower pH in solutions that contain greater than 10⁻⁴ M total

L. E. Eary; Dhanpat Rai

1988-01-01

428

Specular reflectance of aqueous solutions.  

NASA Technical Reports Server (NTRS)

Description of two laboratory instruments for measuring the specular reflectance of aqueous solutions. The instruments are an organic-dye-laser spectrophotometer for the 360- to 650-nm wavelength region and a reflectometer accessory for a Perkin-Elmer E-system spectrophotometer which will operate in the 0.2- to 20-micron wavelength region. The reflectometer accessory has been used to measure the relative infrared specular reflectance in limited spectral regions for aqueous solutions of NaCl, K2SO4, ZnSO4, (NH4)2SO4, and NH4H2PO4 with radiant flux incident at about 70 deg and polarized perpendicular to the plane of incidence. The laser spectrometer has been used to measure the absolute reflectance of aqueous solutions of NaCl in the wavelength region from 575 to 610 nm for light incident at angles of about 60, 65, and 70 deg and polarized parallel to the plane of incidence.

Querry, M. R.; Waring, R. C.; Holland, W. E.; Mansell, G. R.

1971-01-01

429

Investigation of low and mild temperature for synthesis of high quality carbon nanotubes by chemical vapor deposition  

NASA Astrophysics Data System (ADS)

The low reaction temperature for synthesis of carbon nanotubes (CNTs) with high quality was investigated by Ni/MgO catalytic decomposition of CH4 using a home-designed micro-fluidized bed reactor. It was found that the low and mild temperature at 500 ? 550 °C would bring the dynamic equilibrium between the rate of CH4 decomposition and the rate of carbon diffusion over Ni catalyst for continuous precipitation of CNTs in the micro-fluidized bed condition. The CNTs synthesized at the corresponding conditions exhibited high quality with relatively small and mean outer diameter, less defect, and high purity.

Fu, Xu; Cui, Xiangzhong; Wei, Xianhua; Ma, Jiangning

2014-02-01

430

Effect of Mild Hypoinsulinemia on Renal Hypertrophy: Growth Hormone/Insulin-Like Growth Factor I System in Mild Streptozotocin Diabetes  

PubMed Central

The metabolic aberrations associated with diabetes mellitus profoundly alter the growth hormone/insulin-like growth factor I (GH/IGF-I) system. In severe experimental diabetes, serum IGF-I level is reduced, reflecting altered hepatic expression. On the other hand, increased levels of kidney IGF-I have been implicated in the development of diabetic kidney disease. This study aimed to examine the effect of mild experimental diabetes with hypoinsulinemia on both the systemic and renal GH/IGF-I systems in a low-dose streptozotocin (STZ)-induced diabetic rat. Diabetic animals with mild hypoinsulinemia developed renal hyperfiltration within 3 days of diabetes, whereas the renal size increased significantly only between 30 and 48 days of diabetes. Plasma GHlevels were unchanged during the entire course of the study, but a decrease in serum IGF-I, IGF-binding protein 3 (IGFBP-3), and IGF-binding protein 4 (IGFBP-4) occurred after 10, 30, and 48 days. Kidney IGF-I and IGF-binding protein 1 (IGFBP-1) mRNA expression increased after 10 and 30 days of diabetes. A significant increase in kidney IGFBP-1/2, IGFBP-3, and IGFBP-4 proteins was seen after 48 days of diabetes.Apositive correlations was found between renal growth and insulin/glucose ratio (r = .57), kidney IGF-I (r = .57), IGFBP-1 mRNA(r = .43), IGFBP-1/2 (r = .41), and IGFBP-4 levels (r = .40). These results demonstrate hyperfiltration within 3 days of diabetes and a similar response in the IGF-I system in mildly and severely hypoinsulinemic rats; however, renomegaly develops slower in mildly diabetic rats at least partly due to delayed changes in the renal IGF and IGF BPs. PMID:12546279

Khamaisi, Mogher; Flyvbjerg, Allan; Haramati, Ziv; Raz, Gadi; Wexler, Isaiah D.; Raz, Itamar

2002-01-01

431

40 CFR 180.1276 - Tobacco mild green mosaic tobamovirus (TMGMV); temporary exemption from the requirement of a...  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Tobacco mild green mosaic tobamovirus (TMGMV); temporary...Tolerances § 180.1276 Tobacco mild green mosaic tobamovirus (TMGMV); temporary...established for residues of tobacco mild green mosaic tobamovirus in or on all...

2010-07-01

432

Self-Ordered Nanopore Arrays with 300-400 nm Interpore Distances Formed by High Field Accelerated Mild Anodization  

NASA Astrophysics Data System (ADS)

High field accelerated mild anodization was used to fabricate self-ordered nanoporous alumina arrays. The phosphoric acid with various concentrations was used in a wide range of anodization voltages. Two different temperatures for both sides of the samples were employed to maintain a mid level of current density during the anodization process. The interpore distances were seen to vary from 300 to 400 nm when the anodization voltages changed from 150 to 190 V. A nonlinear-inverse relation between electrolyte concentrations of phosphoric acid and anodization voltages was found in the optimum self-ordering conditions. Similar to the hard anodization, the ratio of interpore distance to voltage was 2 nm/V in high field accelerated mild anodization technique.

Ramazani, Abdolali; Almasi Kashi, Mohammad; Maleki, Keyvan; Mohammadniaei, Mohsen

2011-03-01

433

Investigating the enhancing effect of music on autobiographical memory in mild Alzheimer's disease.  

PubMed

The enhancing effect of music on autobiographical memory recall in mild Alzheimer's disease individuals (n = 10; Mini-Mental State Examination score >17/30) and healthy elderly matched individuals (n = 10; Mini-Mental State Examination score 25-30) was investigated. Using a repeated-measures design, each participant was seen on two occasions: once in music condition (Vivaldi's 'Spring' movement from 'The Four Seasons') and once in silence condition, with order counterbalanced. Considerable improvement was found for Alzheimer individuals' recall on the Autobiographical Memory Interview in the music condition, with an interaction for condition by group (p < 0.005). There were no differences in terms of overall arousal using galvanic skin response recordings or attentional errors during the Sustained Attention to Response Task. A significant reduction in state anxiety was found on the State Trait Anxiety Inventory in the music condition (p < 0.001), suggesting anxiety reduction as a potential mechanism underlying the enhancing effect of music on autobiographical memory recall. PMID:16717466

Irish, Muireann; Cunningham, Conal J; Walsh, J Bernard; Coakley, Davis; Lawlor, Brian A; Robertson, Ian H; Coen, Robert F

2006-01-01

434

Detection of free radicals in aqueous extracts of cigarette tar by electron spin resonance  

Microsoft Academic Search

Aqueous extracts of cigarette tar (ACT) autooxidize to produce semiquinone, hydroxyl, and superoxide radicals in air-saturated buffered aqueous solutions. The semiquinone species were detected by direct electron spin resonance (ESR) measurements and identified as o-and p-benzosemiquinone radicals by comparison with the ESR signals of catechol and hydroquinone radicals under similar conditions. The rate of formation of these radicals was dependent

Lun-Yi Zang; Koni Stone; William A. Pryor

1995-01-01

435

Ion spatial distributions at the liquid-vapor interface of aqueous potassium fluoride solutions  

Microsoft Academic Search

X-ray photoemission spectroscopy operating under ambient pressure conditions is used to probe ion distributions throughout the interfacial region of a free-flowing aqueous liquid micro-jet of 6 M potassium fluoride. Varying the energy of the ejected photoelectrons by carrying out experiments as a function of x-ray wavelength measures the composition of the aqueous-vapor interfacial region at various depths. The F to

Matthew A. Brown; R DAuria; I.-F. William Kuo; Maria J. Krisch; David E. Starr; Hendrik Bluhm; Douglas J. Tobias; John C. Hemminger

2008-01-01

436

Oxidation of Glyoxal in the Aqueous Phase  

NASA Astrophysics Data System (ADS)

Large amounts of volatile organic compounds (VOCs) are emitted into the atmosphere from biogenic and anthropogenic sources. The emitted VOCs can be further oxidized in the gas phase as well as in the aqueous phase (cloud droplets, fog, rain and deliquescent particles) to form semivolatile carbonyl compounds. For example, the carbonyl compound glyoxal can be produced by the oxidation process of isoprene. Additionally, these semivolatile carbonyl compounds might be important for the formation of secondary organic aerosol (SOA) by partitioning between gas- and liquid phase of pre-existing particles. In the gas phase as well as in the aqueous phase (cloud droplets, fog, rain and deliquescent particles) these compounds can be further oxidized, e.g., by radicals (OH and NO3) leading to peroxy radicals and then to substituted organics. Two concepts exist in the literature to describe the glyoxal oxidation pathway via alkyl radicals to the peroxy radicals by the addition of molecular oxygen. The first one[1] states that peroxy radical formation occurs with a rate constant of k = 1 × 109 M-1 s-1. The second concept[2] assumes that this is a minor reaction pathway because of the lower rate constant of k = 1 × 106 M-1 s-1. The difference in the rate constants of the oxygen addition is of about three orders of magnitude which might lead to different oxidation products and yields in aqueous solution. In the present work, the formation and the decay of the formed glyoxyl radicals and glyoxyl peroxy radicals were studied in low and high concentrated oxygen solutions using a laser photolysis long path absorption setup (LP-LPA). To clarify the difference a method introduced by Adams et al., 1969[3] to measure the rate constant of the oxygen addition on alkyl radical was modified for laser flash photolysis conditions and successfully applied. In this study a rate constant for the addition reaction of molecular oxygen of k = 8 × 108 M-1 s-1 was measured. This clearly indicates that the oxidation of glyoxal by OH radicals via H abstraction reaction to the glyoxyl alkyl radical followed by the addition of oxygen to the glyoxyl peroxyl radical which, in conclusion, can be well described by the concept of Buxton et al., 1997[1]. 1 Buxton, G. V., T. N. Malone, and G. A. Salmon (1997), J. Chem. Soc. Faraday Trans., 93 (16), 2889-2891. 2 Lim, Y. B., Y. Tan, M. J. Perri, S. P. Seitzinger, and B. J. Turpin (2010), Atmos. Chem. Phys., 10, 10521-10539. 3 Adams, G. E., and R. L. Willson (1969), Trans. Faraday Soc., 65, 2981-2987

Schaefer, Thomas; Herrmann, Hartmut

2014-05-01

437

Direct exfoliation of graphite to graphene in aqueous media with diazaperopyrenium dications.  

PubMed

The 2,9-dimethyldiazaperopyrenium dication can be made from a ubiquitous and inexpensive feedstock in three simple steps as its chloride salt. When mixed with powdered graphite at 23 °C, this behemoth of a molecular compound exfoliates graphite to graphene in water under mild conditions. PMID:23553617

Sampath, Srinivasan; Basuray, Ashish N; Hartlieb, Karel J; Aytun, Taner; Stupp, Samuel I; Stoddart, J Fraser

2013-05-21

438

Aqueous aerosol SOA formation: impact on aerosol physical properties.  

PubMed

Organic chemistry in aerosol water has recently been recognized as a potentially important source of secondary organic aerosol (SOA) material. This SOA material may be surface-active, therefore potentially affecting aerosol heterogeneous activity, ice nucleation, and CCN activity. Aqueous aerosol chemistry has also been shown to be a potential source of light-absorbing products ("brown carbon"). We present results on the formation of secondary organic aerosol material in aerosol water and the associated changes in aerosol physical properties from GAMMA (Gas-Aerosol Model for Mechanism Analysis), a photochemical box model with coupled gas and detailed aqueous aerosol chemistry. The detailed aerosol composition output from GAMMA was coupled with two recently developed modules for predicting a) aerosol surface tension and b) the UV-Vis absorption spectrum of the aerosol, based on our previous laboratory observations. The simulation results suggest that the formation of oligomers and organic acids in bulk aerosol water is unlikely to perturb aerosol surface tension significantly. Isoprene-derived organosulfates are formed in high concentrations in acidic aerosols under low-NO(x) conditions, but more experimental data are needed before the potential impact of these species on aerosol surface tension may be evaluated. Adsorption of surfactants from the gas phase may further suppress aerosol surface tension. Light absorption by aqueous aerosol SOA material is driven by dark glyoxal chemistry and is highest under high-NO(x) conditions, at high relative humidity, in the early morning hours. The wavelength dependence of the predicted absorption spectra is comparable to field observations and the predicted mass absorption efficiencies suggest that aqueous aerosol chemistry can be a significant source of aerosol brown carbon under urban conditions. PMID:24601011

Woo, Joseph L; Kim, Derek D; Schwier, Allison N; Li, Ruizhi; McNeill, V Faye

2013-01-01

439

CSF biomarker changes precede symptom onset of mild cognitive impairment  

PubMed Central

Objective: This study evaluated longitudinal CSF biomarker measures collected when participants were cognitively normal to determine the magnitude and time course of biomarker changes before the onset of clinical symptoms in subjects with mild cognitive impairment (MCI). Methods: Longitudinal CSF collection and cognitive assessments were performed on a cohort of 265 participants who were cognitively normal at their baseline assessment and subsequently developed MCI or dementia. CSF ?-amyloid 1–42 (A?1–42), total tau (t-tau), and phosphorylated tau (p-tau) were determined longitudinally. Consensus diagnoses were completed annually. Cox regression analyses were performed, with baseline CSF values and time-dependent rate of change in CSF values as covariates (adjusted by baseline age, race, and education), in relation to time to onset of mild cognitive symptoms. Results: The mean time from baseline to onset of mild cognitive symptoms was 5.41 years. Increased risk of progressing from normal cognition to onset of clinical symptoms was associated with baseline values of A?1–42, p-tau, and the ratios of p-tau/A?1–42 and t-tau/A?1–42 (p < 0.002). Additionally, the rate of change in the ratios of t-tau/A?1–42 (p < 0.004) and p-tau/A?1–42 (p < 0.02) was greater among participants who were subsequently diagnosed with MCI. Conclusions: Baseline differences in CSF values were predictive of clinical symptoms that were a harbinger of a diagnosis of MCI more than 5 years before symptom onset, and continue to show longitudinal changes as cognitive symptoms develop, demonstrating that baseline and longitudinal changes in CSF biomarkers are evident during the preclinical phase of Alzheimer disease. PMID:24132375

Moghekar, Abhay; Li, Shanshan; Lu, Yi; Li, Ming; Wang, Mei-Cheng; O’Brien, Richard

2013-01-01

440

A rodent model of mild traumatic brain blast injury.  

PubMed

One of the criteria defining mild traumatic brain injury (mTBI) in humans is a loss of consciousness lasting for less than 30 min. mTBI can result in long-term impairment of cognition and behavior. In rats, the length of time it takes a rat to right itself after injury is considered to be an analog for human return to consciousness. This study characterized a rat mild brain blast injury (mBBI) model defined by a righting response reflex time (RRRT) of more than 4 min but less than 10 min. Assessments of motor coordination relying on beam-balance and foot-fault assays and reference memory showed significant impairment in animals exposed to mBBI. This study's hypothesis is that there are inflammatory outcomes to mTBI over time that cause its deleterious effects. For example, mBBI significantly increased brain levels of interleukin (IL)-1? and tumor necrosis factor-? (TNF?) protein. There were significant inflammatory responses in the cortex, hippocampus, thalamus, and amygdala 6 hr after mBBI, as evidenced by increased levels of the inflammatory markers associated with activation of microglia and macrophages, ionized calcium binding adaptor 1 (IBA1), impairment of the blood-brain barrier, and significant neuronal losses. There were significant increases in phosphorylated Tau (p-Tau) levels, a putative precursor to the development of neuroencephalopathy, as early as 6 hr after mBBI in the cortex and the hippocampus but not in the thalamus or the amygdala. There was an apparent correlation between RRRTs and p-Tau protein levels but not IBA1. These results suggest potential therapies for mild blast injuries via blockade of the IL-1? and TNF? receptors. © 2014 Wiley Periodicals, Inc. PMID:25410497

Perez-Polo, J R; Rea, H C; Johnson, K M; Parsley, M A; Unabia, G C; Xu, G-Y; Prough, D; DeWitt, D S; Spratt, H; Hulsebosch, C E

2014-11-19